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Volume II – Section VI: Employer’s Requirements: Contract 16 - 132/33kV Substations and Bays

Chapter 9: 11kV and 33kV Outdoor Isolators and Disconnectors

Page 5 Kenya Power and Lighting Company Limited Substation Bidding Documents – April, 2011

closing. They shall also be capable of withstanding all torsional and bending stresses due tooperation of the isolator. Wherever supported the operating rods shall be provided with bearingson either ends. The operating rods/ pipes shall be provided with suitable universal couplings toaccount for any angular misalignment.

All rotating parts shall be provided with grease packed roller or ball bearings in sealed housingsdesigned to prevent the ingress of moisture, dirt or other foreign matter. Bearings pressure shallbe kept low to ensure long life and ease of operation. Locking pins wherever used shall berustproof.

Signalling of closed position shall not take place unless it is certain that the movable contacts,have reached a position in which rated normal current, peak withstand current and short timewithstand current can be carried safely. Signalling of open position shall not take place unlessmovable contacts have reached a position such that clearance between contacts is at least 80%of the isolating distance.

The position of movable contact system (main blades) of each of the Isolators and earthingswitches shall be indicated by a mechanical indicator at the lower end of the vertical rod of shaft

for the Isolators and earthing switch. The indicator shall be of metal and shall be visible fromoperating level.

The Contractor shall furnish the following details along with quality norms, during detailedengineering stage.

Current transfer arrangement from main blades of isolator along with mV drop immediatelyacross transfer point.

Details to demonstrate smooth transfer of rotary motion from motor shaft to the insulatoralong with stoppers to prevent over travel.

9.5.7 Name Plates

Each disconnector shall be provided with a name plate on which all the information in accordancewith IEC standards.

9.6 Testing and Commissioning

All routine tests shall be carried out in accordance with IEC62271-102. All routine/acceptancetests shall be witnessed by the Employer/his authorised representative. The tests shall include thefollowing:

a) Routine/Acceptance Tests (all units)

Mechanical Operation tests

Power frequency voltage withstand test (dry)

Tests on auxiliary & control circuits

Measurement of resistance of the main circuit.

b) Type Tests:

General requirements are specified in Sub-chapter 3.12 and as follows:

Dielectric test

Temperature test

Measurement of resistance of the main circuit

Short-time withstand and peak withstand current test Mechanical endurance tests, 1000 operations

Mechanical terminal load tests




Chapter 9: 11kV and 33kV Outdoor Isolators and Disconnectors


The Contractor shall submit to the Project Manager two copies of a complete type-testreport of the quoted disconnectors, according to the IEC standards.

The type-test must include also the mechanical endurance test 1000 times open-closeoperating cycles and the mechanical terminal load test.

The type test certificates shall testify that the equipment confirms to all characteristics, asdescribed in this specification.

The type test certificates shall specify the actual values measured during the type tests. Itshall state the names and have the signatures of those responsible for the test result.

c) Test Certificates

Copies of routine/acceptance test certificates shall be produced with the endorsement ofthe inspecting authority to the Employer before effecting despatch. The test report shallcontain the following information.

Complete identification data, including serial No. of the breaker.

Method of application, where applied, duration and interpretation of results in eachtest.

9.7 Compliance with Specification

If the technical requirements are not met or the performance of the circuit breaker during test donot meet the guarantees stated in the technical particulars subject to tolerances specified inrelevant IEC Standards, the Employer shall have the right to reject the faulty component orthe entire breaker. The Contractor shall replace the same in full compliance with the specification.

9.8 Technical Data Sheet

Refer to Chapter 26



SECTION VI: TECHNICAL SPECIFICATIONS

10. TECHNICAL SPECIFICATION FOR STATION AUXIALIARY

TRANSFORMER




Chapter 10: Auxiliary Station Transformers

Page i Kenya Power and Lighting Company Limited Substation Bidding Documents – April 2011

Contents

10 AUXILIARY STATION TRANSFORMERS ............................................ 1

10.1 Scope ............................................................................................................ 1

10.2 Particulars of Electrical System ............ .............. ............. ............. ............. . 1

10.3 Particulars of Environment .............. ............. ............. ............. ............. ........ 1

10.4 Standards, Units and Language ............ .............. ............. ............. ............. . 2

10.5 Detailed Specification .................................................................................. 2

10.5.1 General ............................................................................................................. 2

10.5.2 Windings .......................................................................................................... 3

10.5.3 Cores ................................................................................................................ 3

10.5.4 Tap Changing .................................................................................................. 3 10.5.5 Bushings .......................................................................................................... 4

10.5.6 Tanks and Conservators ................................................................................. 4

10.5.7 Accessories and Fittings ......... ......... .......... ......... ......... .......... ......... .......... ..... 5

10.5.8 Insulating Oil .................................................................................................... 6

10.5.9 Overloading Capability ......... .......... ......... .......... ......... .......... ......... ......... ......... 6

10.5.10 Noise Pollution ................................................................................................ 7

10.5.11 Tests ................................................................................................................. 7

10.6 Packing and Transport................................................................................. 8 10.7 Drawings and Diagrams .............................................................................. 8

10.7.1 Drawings to be supplied .......... ......... .......... ......... ......... .......... ......... .......... ..... 8

10.7.2 Drawings to be supplied with the Contract ................ ......... ......... .......... ....... 8

10.8 Maximum Dimensions and Weights Required ............. .............. ............. ... 9

10.9 Evaluation of Losses ................................................................................... 9

10.9.1 Guaranteed Output and Losses, Liquidated Damages ......... ......... .......... ..... 9

10.9.2 Transformer Output ......................................................................................... 9

10.9.3 Transformer Losses ........................................................................................ 9 10.9.4 Rejection Limits ......... .......... ......... .......... ......... .......... ......... .......... ......... .......... 9

10.9.5 Cost for Evaluation of Losses ......... ......... .......... ......... ......... .......... ......... ....... 9

10.10 Compliance with Specification ............ ............. ............. .............. ............. . 10

10.11 Technical Data Sheet ............ .............. ............. ............. ............. ............. .... 10





Page 1 Kenya Power and Lighting Company Limited Substation Bidding Documents – April 2011

10 AUXILIARY STATION TRANSFORMERS

10.1 S cope

This specification covers the manufacture, testing, supply and delivery of 33kV and 11kVtransformers to be used for Station Auxiliary AC Supplies in substations as well as the spares forthese transformers. All transformers shall be capable of being loaded continuously at the fullrating at maximum 35 0C ambient temperatures while exposed to direct tropical sun.

The station auxiliary transformers shall be of outdoor, mounted type, self-cooled and equippedwith oil level indicator, thermometer, air de-humidifier and all other equipment essential for safeand satisfactory operation.

All materials used in the manufacture of the transformers shall be new and of high commercialquality.

The transformers shall be manufactured to high quality standards.

Type test certificates are to be submitted with the tender for each transformer rating and voltage.Type tests are either to be witnessed by or carried out by an internationally recognised TestInstitute. A minimum requirement is that the Test Institute is unbiased with no direct connection toany private industries and that the institute is engaged in type tests on behalf of internationalclients.

The transformers shall be sourced from manufacturers who have ISO 9001 Certification.Documentary evidence of the ISO 9001 Certification shall be provided with the bid.Manufacturers who cannot submit such certification are liable to be rejected.

Full details including name, place and country of manufacture shall be provided and whether ornot the transformers are produced under license, in which case licence holders name shall bestated.

The relevant Technical Data Sheets in Chapter 26 shall be completed in full to verify or clarify

compliance or otherwise with these Employer requirements. All data will be filled out in the forms.Spares as recommended by the supplier should be included in the scope of supply.

10.2 Particulars of Electrical System

The Plant shall be capable of operation under the general electrical parameters as specified inSub-chapter 3.6.2.

The Auxiliary transformers shall be installed in the substation with the primary to be fed in one ofthe following:

a) From a Three phase overhead-line construction and underground cable systemb) From the 33kV or 11kV busbar through fused links (depending on the LV Voltage at

the substation)

c) From the 33kV or 11kV tertiary winding of the main transformer (depending on thetertiary Voltage of the main transformer)

10.3 Particulars of Environment

The Plant shall be capable of operation under the atmospheric conditions as specified in Sub-chapter 3.6.1.

It is jointly the Contractors and manufacturer’s responsibility to be familiar with any other climaticand physical conditions pertaining to the specific sites as defined in Chapters 1-3 and to allow forall conditions in designs.






Particular attention should be paid in the design of all equipment to ensure that there is nodamage to working parts or insulation through the ingress of dust, insects, vermin which areprevalent for long periods in the year. All orifices and air vents should be covered by easilyreplaceable weather resisting, fine mesh wire where practicable.

Additional Environmental Factors

The design shall be de-rated to allow for reduced cooling effect due to high altitude.

The transformers will be exposed to direct tropical sunlight.

10.4 Standards, Units and Language

All equipment shall be designed, constructed and tested in accordance with requirements of thelatest version of the standards specified herein except to the extent explicitly modified in thespecification and shall be in accordance with the requirements in Chapters 2 and 3.

IEC 60076 and its applicable parts

SI Units of measurements and the English language shall be used throughout.

10.5 Detailed Specification

10.5.1 General

The Transformers shall be of the mineral oil immersed core type suitable for outdoor use withONAN cooling.

All components, all equipment as well as the total plant shall be suitable for operation outdoorsspecifically under these conditions and in general under sub-tropical conditions at altitudes of upto 2200m above sea level, to the conditions stated in Sub-chapters 10.2 and 10.3 and shall have

the characteristics as given in Chapter 26 Technical Data Sheets .Equipment and components as well as the total plant shall withstand the thermal and mechanicalstresses forced by the rated continuous currents as well as the over currents as specified above.

Defect liability and warranties shall be as specified in Sub-chapter 3.13 .

All transformers shall have a guaranteed life span of at least 25 years operating continuouslyunder full rated power at specified ambient temperatures on any tapping under the followingconditions:

a) With the voltage of the untapped winding at normal, without the need to de-rate thetransformer at the extreme tap positions and without oil temperature rise exceeding55 C at the top of the transformer. The winding temperature rise shall not exceed60 C.

b) With voltage applied up to 10% in excess of the rated tapping voltages and withoutinjurious overheating.

c) Transformers shall be connected in accordance with BS 171: three phasetransformers to Vector Group reference Dyn11.

The LV neutrals shall be brought out of the tank to a readily accessible terminal and shall not beearthed inside the tank, unless otherwise specified in the enquiry.

Transformers on a particular contract with similar kVA rating, voltage ratios and connections shallbe suitable for parallel operation on all relevant taps under which conditions they should share theload in proportion to their ratings subject to the tolerances on impedance laid down in IEC 60076or BS 171.Normally it shall not be required to parallel Auxiliary transformers in a substation. However, if it isrequired to parallel any transformers then full details of any existing transformers will be provided






when tenders are placed.

Low impedance transformers are preferred, a maximum of 5% being envisaged on any size withno plus tolerance.

An oil gauge shall be provided for non-sealed transformers.

Sealed transformers shall not be accepted.

10.5.2 Windings

Taps shall be provided in the HV windings, preferably in the electrical centre of the windings, topermit variation of the number of HV turns without any variation in the kVA rating. The variationsshall be effected by means of a manually operated tapping switch to be provided in accordancewith Sub-chapter 10.5.4.

All windings and terminations shall be fully insulated and those for service above 1000 volts shallbe designed for impulse voltage tests.

Designs shall be such that electrical stresses are as uniform as possible throughout the windingsunder impulse conditions.

Windings shall be vacuum impregnated and insulating materials shall not be liable to soften,shrink, become brittle, carbonise, deteriorate, or collapse in any way during service.

LV windings of Aluminium sheet are not acceptable. Transformers with such windings will berejected.

10.5.3 Cores

The magnetic circuit shall be earthed to the core clamping structure, at one point only, and thecore assembly to the tank cover. Where transformers are not sealed, readily accessibleremovable bolted links shall be employed for the earthing connections.

The general construction of the cores, framework and the clamping arrangements shall be robust

and such that they will be capable of withstanding completely any stresses which may occur dueto handling, transport or service. All cores and yokes shall be terminated and clamped by meansof a suitable framework. Suitable means shall be provided for lifting the cores from the tanks.

It shall not be possible for the core to move relative to the tank during handling or transport.Designs that contravene this requirement will be rejected.

Particular attention shall be paid to maintaining low core loss consistent with sound design.

10.5.4 Tap Changing

Transformers shall be provided with approved off-circuit type tap changing equipment. A fullyinsulated off circuit externally manually operated ganged tapping switch shall be separatelycapable of withstanding the specified impulse voltage when connected to the transformerwindings.Clearly visible tap position indication shall be provided. The tapping switch shall be operated bymeans of an external handle, which can be positively located and locked in each operatingposition.

The switch shall be mechanically robust and provided with a device between the handle and theswitch to permit operation without strain in the event of imperfect alignment between switch andhandle. The switch-operating shaft shall be fully insulated as between tank and switch and shallbe provided with a suitable oil and vacuum tight gland where it passes through the tank.

The use of wood shall be avoided wherever possible and all the supports and terminal boardsshall be completely unaffected by hot oil and shall be non-moisture absorbent.

High grade insulating materials shall be used in the construction of tapping switches, which shallbe designed with special attention to the elimination of points where tracking is likely to occur.

Tap switches shall be mounted on supports made of suitable high strength insulating material and






shall be provided with self-aligning spring loaded wiping contacts capable of maintaining goodelectrical contact without the need for periodic maintenance.

All clearance between tapping switch contacts and leads shall be indicated on drawings submittedat the time of tendering and such clearances shall be sufficient to prevent tracking or flashover inthe event of carbon or sludge deposits forming on leakage paths.

Five (5) tap positions shall be provided on the H.V winding as follows: Minus 5%; Minus 2.5%; 0%(Normal); Plus 2.5%; and Plus 5%.

10.5.5 Bushings

All line terminals and neutral connections where specified, shall be brought out to porcelainoutdoor type terminal bushings. The bushings shall be the outdoor type.

Arcing horns with equal double gaps shall be fitted on all transformer bushings above 660 volt.The total gap length (for two gaps) shall be set at 60 to 70mm for 11kV and 140 to 150mm for33kV nominal voltage.

The bushings shall have minimum Creepage distances of 670mm and 250mm for nominalvoltages of 33kV and 11kV respectively.

10.5.6 Tanks and Conservators

10.5.6.1 General

Drain valves may be either screwed or flanged whilst conservator isolator valves shall be flanged.Drain valves shall be complete with captive plugs which shall be either of non-ferrous metal orgalvanised.

All internal steel surfaces or tanks and conservators shall be shot blasted and cleaned, and a coatof protecting compound, unaffected by hot oil, should be applied.

All external surfaces and parts made of steel are to be thoroughly shot blasted and cleaned, after

which two coats of priming paint, preferably of zinc chromate, one intermediate coat, and one coatof finishing paint are to be applied. The colour of the finishing coat shall be medium Sea Grey,Colour No. 637 to BS 381C or near equivalent as may be approved by the Project Manager.

Transformers on which the paints are found to flake off or deteriorate within the guarantee periodshall be suitably cleaned and repainted free of charge by the Contractor. The Contractor shallprovide an undertaking to carry out this corrective work should the deterioration occur.Contractors providing such transformers will not in the future be given the opportunity to offertransformers to the Employer.

10.5.6.2 Tanks

Each transformer shall be housed in a tank of welded steel plate construction suitably stiffened

where necessary but with a flat base.Wheels as rollers shall be provided for transformers rated above 500kVA. Transformers ratedequal to or less than 500kVA shall not be provided with wheels as rollers.

The lifting lugs shall be suitable for lifting the transformer bodily by means of a hoist or cranewhen it is completely assembled and ready for service.

All transformers up to and including 315kVA rating shall be provided with four fixing lugs on thebase drilled with 16mm holes for bolting to a platform.

The fixing holes shall project beyond the ends of the tank and be placed to provide the mostpracticable stable arrangement.

10.5.6.3 Conservators

Conservators, shall be dimensioned such that oil expansion may occur over the working range oftemperature from no load with the transformer cold to full load at specified ambient airtemperature ranges while the sump pipe remains covered and the oil level is visible or indicated.






Drain plugs shall preferably incorporate approved sampling facilities, and shall be mounted at thelowest part of the conservator tank and so designed that the sampling device can be readilycleared in the event of its being blocked by an accumulation of sludge etc., without the necessityof having to dismantle the device completely.

Oil level gauges on conservator tanks shall be of the refracting plate glass or other approved type,marked with the level at 20 OC at no-load and capable of indicating the level of oil over the

specified working range.Where dehydrating breathers are specified they shall be of the Silica gel type which giveindication of moisture absorption by change in colour of the charge.

An inspection window shall be provided and mounted in a position convenient for inspection. Thebreather is to incorporate an oil seal to prevent contact with the external air when breathing is nottaking place. The breather is to be fitted on the LV end of the transformer.

10.5.7 Accessories and Fittings

All transformers shall be provided with accessories and fittings in accordance with the tablesbelow, unless otherwise specified in Chapter 26 Technical Data Sheets.

In the following table: ‘Y’ means Y es (To be provided)

‘N’ means No (Not to be provided)

Table 10.5.7: Accessories and Fittings for Auxiliary TransformersTRANSFORMER TANK FITTINGS Transformer Nominal Ratings

11kV Primary Voltage 33kV PrimaryVoltage

< 100 kVA ≥100<500

kVA

≥500kVA

<500kVA

≥500kVA

FreeBreathing

Sealed

1 Conservator N N Y Y Y Y

2 Drain valve with captive sealing plug Y N Y Y Y Y

3 Lifting lugs Y Y Y Y Y Y

4 Thermometer Pocket N N N Y N Y

5 Rating and Diagram plate Y Y Y Y Y Y

6 Hanger irons Y Y N N N N

7 Platform mounting lugs Y Y Y N Y N

8 Earthing Terminal Y Y Y Y Y Y9 Lightning arrestor brackets N N N Y N Y

10 Dial type thermometer N N N Y N Y

11 Jacking pads N N Required only when the mass of thecomplete transformer is ≥1000 kg

12 Plain breather Y N N N N N

13 Oil gauge Y Y On Conservator

14 Mounting plate for Item 6 to be suitablefor mounting marshalling box Item 17)

N N N Y N Y

15 Lashing down facilities Y Y Y Y Y Y16 Marshalling box for Item 10 of Tank

fitting and Item 7 of ConservatorN N N Y N Y






TRANSFORMER TANK FITTINGS Transformer Nominal Ratings

11kV Primary Voltage 33kV PrimaryVoltage

< 100 kVA ≥100<500kVA

≥500kVA

<500kVA

≥500kVA

Free

Breathing

Sealed

fittings

Conservator fittings

1 Drain plugs N/A Y Y Y Y

2 Sampler N/A Y Y Y Y

3 Separate filling hole with caps N/A Y Y Y Y

4 Dehydrating breather N/A >100kVA

Y Y Y

5 Plain breather N/A 100

kVA

N N N

6 Oil gauge N/A Y Y Y Y

7 Gas and oil actuated relay N/A N Y N Y

8 Conservator isolating valve N/A N Y N Y

Rating and diagram plates shall be of engraved brass or other approved non-corroding materialand shall be placed on the L.V side of the transformer.

Where a thermometer pocket is provided, it shall be of a thin walled metal mounted in the tankcover. The pocket shall project 25mm outside of the tank and shall be threaded along the wholeprojecting portion with a 19mm B.S.P. male thread, a screwed cap shall be provided to cover thepocket when not in use. The pocket shall have internal dimensions of not less than 19mmdiameter and 115mm length.

Hanger irons, where specified, shall be suitable for suspending the transformer from a 102mm x51mm Mild Steel Channel cross-arm, bolted to the vertical legs of an 'H' pole. A suitable stop shallbe provided at the base of the tank to enable the transformer to be suspended vertically, and restagainst a similar 102mm x 51mm Channel provided on the 'H' pole at a lower level for thispurpose. The hanger irons shall be drilled for an M16 bolt to enable them to be bolted to thevertical web of the cross-arm and thereby prevent any lateral movement of the transformer. Thehanger irons shall be mounted on the LV side of the transformer tank.

10.5.8 Insulating Oil

The transformers shall be supplied with low viscosity mineral insulating oil, which complies inevery respect with the provisions of BS 148, IEC: 60156 and IEC: 60296.

10.5.9 Overloading Capability

The transformer shall be capable of overload at 35 C ambient temperature without reduction inthe anticipated working life of the transformer, as shown in the curve below.






TRANSFORMER OVERLOAD CAPABILITY

100

105

110

115

120

125

130

135

140

145

150

2 4 6 8 1 0

1 2

1 4

1 6

1 8

2 0

2 2

2 4

Hours

P e r c e n

t a g e

L o

a d

% load

The maximum load at other periods is assumed to be 70% of the transformer rating for the abovetransformer overload capability curve.

10.5.10 Noise Pollution

The maximum values for the noise levels of the various distribution transformers shall be as givenin the table below:

Transformer Rating kVA Maximum NoiseLevel dB(A)

Less than or equal to 50kVA 48Between 50 and 315kVA 55

Between 315 and 500kVA 56




Above 1600kVA 61

Transformers with Noise Pollution levels higher than that given above will be rejected.

10.5.11 Tests

Electrical tests are to be carried out according to IEC 60076 and its parts. Routine covering testcertificates shall be submitted immediately after completion of tests in the factory, for each andevery identical group of transformers.

The following tests shall be carried out in addition to the routine tests:

a) As a type test, a temperature rise test on each different rating of transformer.

b) As a special test, an impulse voltage withstand test including chopped waves on each

different rating of transformer.






10.8 Maximum Dimensions and Weights Required

The dimensions of the transformers are as shown on the drawings specified above.

The dimensions referred to above shall mean the following:

Maximum height shall be denoted by (h1)

Maximum width shall be denoted by (a1) Maximum depth shall be denoted by (b)

The maximum dimensions in mm and weights in kg shall be as indicated in the table below. Anytransformer whose dimensions and weights exceed the stated values will be rejected.

Rating kVA Ratio kV Height (h1) Depth (b) Width (a1) Weight (kg)

200 11/0.4 1725 1300 1300 1074

315 11/0.4 1850 1330 1400 1757

500 11/0.4 1920 1890 1650 1990

200 33/0.4 2140 1620 1620 1847315 33/0.4 2240 1610 1700 2208

500 33/0.4 2260 2290 1940 3114

10.9 Evaluation of Losses

10.9.1 Guaranteed Output and Losses, Liquidated Damages

Failure to meet the guaranteed outputs and losses shall be dealt with as follows:

10.9.2 Transformer OutputIf the guaranteed continuous output at rated voltage of any transformer has to be reduced belowthe guaranteed value in order to maintain the temperature rises of any part of the transformerwithin the guaranteed limits, liquidated damages shall be paid at the rate used in 10.9.5 below indetermining the liquidated damages for functional guarantees related to deficiency in transformercapacity below(above) the guaranteed figures

10.9.3 Transformer Losses

If the total transformer losses of any transformer, as determined by these, without any tolerances,at rated voltage, frequency and 100% rated kVA (on principal tapping) exceed the guaranteedtotal losses, the excess in losses shall be capitalised at the rates stated in Sub-Clause 13.2 belowand the resulting amount shall be paid as liquidated damages.The payment on account of failure of one or more transformer to meet the guaranteed output andguaranteed losses shall be applied individually, as the case may be, and shall therefore beunderstood to be cumulative.

10.9.4 Rejection Limits

Should any transformer fail to meet the guaranteed output by more than 5% (five per cent) or thetotal losses should exceed the total guaranteed losses by more than 1/5 (one fifth), and shouldthe Contractor fail within a reasonable time to modify the transformer in order to increase theoutput and/or reduce the losses sufficiently, THE EMPLOYER shall have the option to reject thetransformer. Test certificates shall be submitted to verify the test results.

10.9.5 Cost for Evaluation of Losses

Transformer losses will be evaluated based on the following figures:






RATING (KVA) PHASE HIGHESTSYSTEMVOLTAGE (KV)

NO LOADLOSSES$/KW

FULL LOADLOSSES$/KW

200 3 36 1070 4300

NB:- Where tenders are being compared, losses will be capitalized at the above rate and added to

the bid evaluated price of the transformer.


If the technical requirements are not met or the performance of the circuit breaker during test donot meet the guarantees stated in the technical particulars subject to tolerances specified inrelevant IEC Standards, the Employer shall have the right to reject the faulty component orthe entire breaker. The Contractor shall replace the same in full compliance with the specification.


Refer to Chapter 26




11. TECHNICAL SPECIFICATION FOR INSTRUMENT

TRANSFORMERS



Volume II – Section VI : Employer’s Requirements : Contract 16Contract 16 - 132/33kV Substations and Bays

Chapter 11: Instrument Transformers

Page i Kenya Power and Lighting Company Limited Substation Bidding Documents – October ’09

Contents

11 INSTRUMENT TRANSFORMERS ...................................................... 1

11.1

General .......................................................................................................... 1

11.2 Particulars of Electrical System ............ ............. ............ ............. ............. ... 1

11.3 Particulars of Environment .......................................................................... 1

11.4 Standards, Units and Language ............ ............. ............ ............. ............. ... 2

11.5 General Specification of Instrument Transformers ............. ............. ......... 2

11.5.1 General ............................................................................................................. 2

11.5.2 Bushing/Insulators .......................................................................................... 2

11.5.3 Insulating Oil .................................................................................................... 2

11.5.4 Nameplate ........................................................................................................ 2 11.5.5 Spare Parts and Maintenance Equipment ......... ......... .......... ......... ......... ........ 3

11.6 Detailed Specification of Current Transformers ........... ............. ............. ... 3

11.6.1 Specific Requirements .......... ......... ......... ......... .......... ......... ......... .......... ......... 3

11.6.2 Additional Type Tests ......... ......... .......... ......... ......... .......... ......... ......... ......... .. 4

11.6.3 Routine (Type) Tests ....................................................................................... 5

11.6.4 Commissioning Tests ..................................................................................... 5

11.6.5 Technical Parameters for Current Transformers .............. ......... .......... ......... 5

11.7 Detailed Specification of Voltage Transformers ........... ............. ............. ... 6 11.7.1 Specific Requirement ........ .......... ......... ......... .......... ......... ......... ......... .......... ... 6

11.7.2 Additional Type Tests ......... ......... .......... ......... ......... .......... ......... ......... ......... .. 7

11.7.3 Routine Tests ................................................................................................... 7

11.7.4 Commissioning Tests for VTs and CVTs ........ .......... ......... ......... .......... ......... 7

11.7.5 Technical Parameters of Capacitive Voltage Transformers Rated132 kV and above ............................................................................................. 8

11.8 Compliance with Specification ............ ............. ............ ............. ............. ..... 8

11.9 Technical Data Sheet ............. ............. ............ .............. ............ ............. ....... 8





Page 1 Kenya Power and Lighting Company Limited Substation Bidding Documents – October ’09

11 INSTRUMENT TRANSFORMERS

11.1 General

This Chapter covers the technical requirements of instrument transformers to be installed inoutdoor switchyards.

The supply of instrument transformers shall be complete with all apparatus and requisiteaccessories, including a terminal box for each unit and a common marshalling box for a set of 3instrument transformers, fixing materials etc.

The Steel structure, concrete foundations for apparatus supports, cable ducts and trenches arepart of the civil engineering works and are specified in Chapters 23 and 24: Civil Works andSteel Structures respectively.

Material and workmanship throughout shall comply with Chapter 3.

Provisions shall be made in the design of the instrument transformers to ensure that the properoperation of these items and their accessories is not impaired by vermin, insects, small animals

and birds, etc. All exposed surfaces of frames, etc. which normally would be painted when in service, shall haveone rust-protective coat of paint and at least one coat of a synthetic resin having excellent waterresisting properties. Total paint thickness shall not be less than 0.06 mm. All exposed parts of theisolators shall be weather proof.

All individual parts and subassemblies of instrument transformers of the same type and ratingshall be completely interchangeable without affecting its performance.

The instrument transformer tank along with top metallics shall be hot dip galvanised or painted asper IS - 5, shade 697.

The impregnation details along with tests/checks to ensure successful completion of impregnation

cycle shall be furnished for approval.




The Plant shall be capable of operation under the atmospheric conditions as specified in Sub-

chapter 3.6.1. It is jointly the Contractors and manufacturer’s responsi bility to be familiar with any other climaticand physical conditions pertaining to the specific sites as defined in Chapters 1-3 and to allow forall conditions in designs.


Additional Environmental Factors

The design shall be de-rated to allow for reduced cooling effect due to high altitude.

The transformers will be exposed to direct tropical sunlight.







All equipment shall be designed, constructed and tested in accordance with requirements of thelatest version of the standards specified below except to the extent explicitly modified in thespecification:

Current transformers IEC 60044-1

Voltage transformers IEC 60044-2


11.5 General Specification of Instrument Transformers

11.5.1 General

Instrument transformers shall be oil filled, with shedded porcelain bushings/ Insulators suitable foroutdoor service and upright mounting on steel structures.

Polyconcrete instrument transformers are not acceptable. The ratings and design criteria for theplant and equipment shall be in accordance with the requirements in Chapters 2 and 3.

All components, all equipment as well as the total plant shall be suitable for operation outdoorsspecifically under these conditions and in general under sub-tropical conditions at altitudes of upto 2200m above sea level, to the conditions stated in Sub-chapters Error! Reference sourcenot found. and Error! Reference source not found. and shall have the characteristics as givenin Chapter 26 Technical Data Sheets .

Equipment and components as well as the total plant shall withstand the thermal and mechanicalstresses forced by the rated continuous currents as well as the over currents as specified above.

All transformers shall have a guaranteed life span of at least 25 years operating continuouslyunder full rated power at specified ambient temperatures.


The features and constructional details of the equipment shall be in accordance with requirementsstipulated hereunder.

11.5.2 Bushing/Insulators

Bushings/Insulators shall conform to requirements stipulated in Sub-chapter 3.27. Thebushing/insulator for CT shall be one piece without any metallic flange joint.

Bushings shall be provided with oil filling and drain plugs, oil sight glass of CT and forelectromagnetic unit of CVT, etc. The bushing/insulator of instrument transformer shall havecantilever strength of not less than 350 kg for Instrument transformers.

Instruments transformers shall be hermetically sealed units. The Contractor shall furnish details ofthe arrangements made for the sealing of instrument transformers.

The Contractor shall also furnish the details of site tests to check the effectiveness of hermeticsealing for approval.

Polarity marks shall indelibly be marked on each instrument transformer and at the lead terminalsat the associated terminal block.

11.5.3 Insulating Oil

Insulating oil to be used for instrument transformers (required for first filling) shall be of EHV gradeand shall conform to IEC: 60156 and IEC: 60296 or equivalent international standard.

11.5.4 Nameplate

Nameplate shall conform to the requirements of IEC incorporating the year of manufacture. The






rated current, extended current rating in case of current transformers and rated voltage, voltagefactor in case of voltage Transformers shall be clearly indicated on the nameplate. The ratedthermal current in case of CT shall also be marked on the nameplate.

The intermediate voltage in case of capacitor voltage transformer shall be indicated on thenameplate.

11.5.5 Spare Parts and Maintenance EquipmentThe Contractor shall include under this project, spare parts and special maintenance equipment inaccordance with Sub-chapter 3.16.

11.6 Detailed Specification of Current Transformers

11.6.1 Specific Requirements

The current transformers shall be single-phase, oil-immersed mounted in one insulator (33 and 11kV can be resin encapsulated). They shall be mounted on lattice steel support structures.

The characteristics of the current transformers shall comply with the provisions stipulated in theIEC standards.

Current transformers shall have single primary either ring type, or hair pin type and suitablydesigned for bringing out the secondary terminals in a weather proof (IP 55) terminal box at thebottom. These secondary terminals shall be terminated to stud type non disconnecting terminalblocks inside the terminal box

Each current transformer shall be equipped with an oil level gauge to be easily visible from theground.

The current transformers shall be supplied including oil filling.

The oil of the current transformer shall be hermetically sealed against the ambient air. The sealingmethod shall be described in the documentation of the CT, as well as the method ofcompensation for changes in the oil volume due to temperature changes.

The CT shall be designed as to achieve the minimum risks of explosion in service. TheContractor shall clearly indicate what measures are provided for relieving dangerous pressurerises that may develop due to an internal electrical fault.

The expansion chamber at the top of the porcelain insulators should be suitable for expansion ofoil.

The primary connections shall be silver-plated.

Facilities shall be provided at terminal blocks in the marshalling box for star delta formation, short

circuiting and grounding of CT secondary terminals. An earth connection to the housing shall alsobe provided.

The current transformers shall be designed to carry continuously a current of 120% of the ratedcurrent. For 400 kV, 330 kV and 132 kV class CTs, the rated extended primary current shall be120% (or 150% if applicable) on all cores of the CTs

The rated current of the secondary windings shall be 1 A unless otherwise specifies in Section 2-III, Scope of Works.

The different cores shall have the following characteristics:

a) The core(s) for measuring:

i) Accuracy class 0.5ii) Instrument security factor equal

to or less than 5






b) The core (s) for metering

i) Accuracy

ii) Instrument security factor equal

c) The core(s) for protection:

Class 0.25

i) Accuracy class 5 P

ii) Accuracy limit factor equal to orgreater than

iii) Burden

20

30VA

d) The core(s) for busbar protection,differential, restricted earth fault:

i) Accuracy class X

ii) Knee point voltage scheme Vkn=250 volts, Imag=8mA30VA

Different ratios specified shall be achieved by secondary taps only and primary reconnection shallnot be accepted.

The current transformers shall be suitable for high speed auto reclosing. The Contractor shalldemonstrate that the current transformers selected will ensure correct functioning of the associatedprotective equipment.

Core lamination shall be of cold rolled grain oriented silicon steel or other equivalent alloys. Thecores used for protection shall produce undistorted secondary current under transient conditionsat all ratios with specified CT parameters

The output of the current transformers for measuring and protection purposes shall be determinedaccording to the technical requirements, but shall not be less than 125% of the overall computed(design) burden of the connected apparatus and conductors.

For current transformer, characteristics shall be such as to provide satisfactory performance ofburdens ranging from 25% to 100% of rated burden over a range of 10% to 100% of rated currentin case of metering CTs and up to the accuracy limit factor/knee point voltage in case of relayingCTs. The guaranteed burdens and accuracy class are to be intended as simultaneous for allcores.

The instrument security factor at all ratios shall be less than five (5) for metering core. The wiringdiagram plate for the interconnections of the three single phase CTs shall be provided inside the

marshalling box Power frequency test voltage on secondary windings, 1 min. 2kV

Overvoltage inter-turn test, 1 min. 3.5 kV peak

The current transformer shall be suitable for horizontal transportation. It shall be ensured that theCT is able to withstand all the stresses imposed on it while transporting and there shall be nodamage in transit. The Contractor shall submit the details of packing design to theEmployer/Engineer for review.

11.6.2 Additional Type Tests

In accordance with the requirements in Sub-chapter 3.12, Current Transformers should havebeen type tested and shall be subjected to routine tests in accordance with IEC 60044-1 (orequivalent).

The test reports of the type tests and the following additional type tests shall also be submitted for






11.7 Detailed Specification of Voltage Transformers

11.7.1 Specific Requirement

Voltage transformers for 132 kV and above shall be of capacitor voltage divider (CVT) type withelectromagnetic units and shall be suitable for carrier coupling. Where carrier coupling is specifiedfor 66 kV, a CVT type Voltage transformers shall also be provided.

The single-phase voltage transformers shall be oil immersed and shall be mounted in one insulator.(33 kV and 11 kV can be resin encapsulated) They shall be mounted on steel structures.

The voltage transformers shall be supplied including oil filling.

The oil of the voltage transformers shall be hermetically sealed against the ambient air. The sealingmethods shall be described in the documentation of the CVT, as well as the method ofcompensation for changes in the oil volume due to temperature changes.

The Contractor shall indicate what measures are provided for relieving dangerous pressure risesthat may develop due to an internal electrical fault.

Each voltage transformer shall be equipped with an oil level gauge to be easily visible from ground

level.Voltage transformers secondaries shall be protected by HRC cartridge type fuses for all thewindings. In addition fuses shall be provided for the protection and metering windings for fuse onmonitoring scheme. The secondary terminals of the CVTs shall be terminated to the stud type non- disconnecting terminal blocks in the individual phase secondary boxes via the fuse.

CVTs shall be suitable for high frequency (HF) coupling required for power line carriercommunication. Carrier signal must be prevented from flowing into potential transformer (EMU)circuit by means of a RF choke/reactor suitable for effectively blocking the carrier signals over theentire carrier frequency range i.e. 40 to 500 KHz. Details of the arrangement shall be shown onthe design. H.F. terminal of the CVT shall be brought out through a suitable bushing and shall beeasily accessible for connection to the coupling filters of the carrier communication equipment,when utilised. Further earthing link with fastener to be provided for HF terminal.The electromagnetic unit comprising compensating reactor, intermediate transformer andprotective and damping devices shall have separate terminal box with all the secondary terminalsbrought out.

The damping device that shall be permanently connected to one of the secondary windings shallbe capable of suppressing the ferro-resonance oscillations.

The accuracy of 0.2 on secondary III should be maintained throughout the entire burden range upto 100 VA on all the windings without any adjustments during operation.

All secondary connections shall be connected to a terminal block that shall be located in adust-proof and watertight terminal box and shall be clearly labelled. It should be ensured thataccess to secondary terminals is without any danger of access to high voltage circuit.

The primary connections shall be silver-plated.

A protective surge arrester shall be provided to prevent breakdown of insulation by incomingsurges and to limit abnormal rise of terminal voltage of shunt capacitor/primary winding, tuningreactor/RF choke etc. due to short circuit in transformer secondaries. In case of an alternatearrangement, the Contractor shall provide the details for consideration by the Employer/Engineer.

The wiring diagram for the interconnection of the three single phase CVTs shall be providedinside the marshalling box in such a manner that it does not deteriorate with time.

An earth connection to the housing shall be provided.

The windings for measuring purposes shall be designed for an accuracy according to class 0.2.Rated secondary voltage shall be 110 / 3 V.

The voltage transformers shall have two additional secondary windings for the protective purposesdesigned for an accuracy according to class 3P.






The secondaries shall be provided with miniature circuit breakers with alarm contacts.

The characteristics of the voltage transformers shall comply with the provisions stipulated in IEC60044-2.

The capacities of all windings shall be determined according to the technical requirements, but shallnot be less than 125% of the overall computed (design) burden of the connected apparatus and

conductors.Power frequency test voltage on secondary windings, 1 min. 2 kV.

11.7.2 Additional Type Tests

In accordance with the requirements in Sub-chapter 3.12, Voltage Transformers should havebeen type tested and shall be subjected to routine tests in accordance with IEC 60044-2.

The test reports of the type tests and the following additional type tests shall also be submitted forthe Employer/Engineer's review:

a) High frequency capacitance and equivalent series resistance measurement;

b) Seismic withstand test;

c) Stray capacitance and stray conductance measurement of the low voltage terminal;

d) Determination of temperature coefficient test;.

e) Radio interference test.

11.7.3 Routine Tests

The current and voltage transformer shall be subjected to the following routine/site tests inaddition to routine tests as per IEC 60060 and 60044.

a) Capacitance and loss angle measurement before and after voltage;

b) Partial discharge test on capacitor dividers;

c) Sealing test;

d) Natural frequency of capacitor unit determination (Resonant frequency of capacitorunits).

11.7.4 Commissioning Tests for VTs and CVTs

An indicative list of tests is given below. The Contractor shall be responsible for any additionaltest (including all the associated costs) based on specialities of the items as per the fieldQ.P./Instructions of the equipment Supplier or the Employer/Project Manager. The Contractorshall arrange all instruments required for conducting these tests along with calibration certificatesand shall furnish the list of instruments to the Employer/Project Manager for approval.

a) Insulation Resistance test for primary (if applicable) and secondary winding.

b) Polarity test

c) Ratio test

d) Dielectric test of oil (wherever applicable).

e) Tan delta and capacitance measurement between:

i) HV - HF point

ii) HF Point - Ground point of Intermediate Transformer.

iii) HV - Ground point of Intermediate Transformer primary winding

f) Secondary winding resistance measurement.






11.7.5 Technical Parameters of Capacitive Voltage Transformers Rated 132 kV andabove

System fault level 31.5 kA for 1 second

Standard reference range 96% to 102% for protection and 99% of

frequencies for which the accuracies arevalid

High frequency capacitance for entire carrierfrequency range

Within 80% to 150% of rated capacitance

Equivalent series resistance over the entirecarrier frequency range

Less than 40 ohms.

Stray capacitance and stray conductance of theLV terminal over entire carrier frequency range

As per IEC

One minute power frequency withstand voltage:

i) Between LV(HF) terminal and earthterminal 10 kV (rms) for exposed terminals and 4 KV(rms) for terminals enclosed in a weatherproof box

ii) For secondary winding 3 kV (rms)

Maximum temperature rise over design ambienttemperature

As per IEC

Number of terminals in Control cabinet All terminals of CVT are wired up tomarshalling box plus12 terminals exclusivelyfor the Employer's use.

Rated Total Thermal burden (VA) 400 VA


If the technical requirements are not met or the performance of the equipment during test do notmeet the guarantees stated in the technical particulars subject to tolerances specified in relevantIEC Standards, the Employer shall have the right to reject the faulty component or the entireitem. The Contractor shall replace the same in full compliance with the specification.


Refer to Chapter 26




Chapter 12: Lighting Arresters


Contents

12 LIGHTNING ARRESTERS .................................................................. 1

12.1 General .......................................................................................................... 1 12.2 Particulars of Electrical System ............ ............. ............ ............. ............. ... 1




12.5.1 General ............................................................................................................. 1

12.5.2 Duty Requirements ......... .......... ......... ......... .......... ......... ......... ......... .......... ...... 2

12.5.3 Constructional Features ................................................................................. 2

12.5.4 Fittings and Accessories ........ .......... ......... .......... ......... ......... ......... .......... ...... 3

12.6 Testing and Commissioning ....................................................................... 3

12.6.1 Type Tests ........................................................................................................ 3

12.6.2 Acceptance Tests .......... ......... .......... ......... ......... ......... ......... .......... ......... ........ 4

12.6.3 Special Acceptance Test .......... ......... ......... .......... ......... ......... ......... .......... ...... 4

12.6.4 Routine Tests ................................................................................................... 4

12.6.5 Test on Surge Monitors ................................................................................... 4

12.6.6 Test on insulators ............................................................................................ 4


12.7 Compliance with Specification .................................................................... 4







12 LIGHTNING ARRESTERS

12.1 General

This Chapter covers the technical requirements of lightning arresters to be installed in outdoorswitchyards.

The Surge arresters shall metal oxide gapless type conforming to IEC 60099-4 except to theextent modified in the specification and shall also be in accordance with requirements underChapters 2 and 3.

Arresters shall be of hermetically sealed units, self-supporting construction, suitable for mountingon tubular.

The relevant Technical Data Sheets in Chapter 26 shall be completed in full to verify or clarifycompliance or otherwise with these Employer requirements. All data will be filled out in the forms.

Spares as recommended by the supplier should be included in the scope of supply.





It is jointly the Contractors and manufacture r’s responsibility to be familiar with any other climatic

and physical conditions pertaining to the specific sites as defined in Chapters 1-3 and to allow forall conditions in designs.



All equipment shall be designed, constructed and tested in accordance with requirements of the

latest version of the standards herein except to the extent explicitly modified in this specification: IEC 60099-4



12.5.1 General

The lightning arresters shall be of the metal oxide gapless type, complying with IEC 60099-4. Asall other main parts of the switchyard they shall be mounted on steel structures.

The ratings and design criteria for the plant and equipment shall be in accordance with therequirements in Chapters 2 and 3.

All components, all equipment as well as the total plant shall be suitable for operation outdoors






specifically under these conditions and in general under sub-tropical conditions at altitudes of upto 2200m above sea level, to the conditions stated in Sub-chapters 12.2 and 12.3 and shall havethe characteristics as given in Chapter 26 Technical Data Sheets .



The features and constructional details of the equipment shall be in accordance with requirementsstipulated hereunder.

12.5.2 Duty Requirements

The surge arresters shall be of heavy-duty station class and gapless type without any series orshunt gaps.

The surge arresters shall be capable of discharging over-voltages occurring during switching ofunloaded transformers, reactors and long lines.

132kV and 33kV class arresters shall be capable for discharging energy equivalent to class 3 ofIEC on two successive operations.

The surge arresters shall be suitable for withstanding forces as defined in IEC Standards.

The reference current of the arresters shall be high enough to eliminate the influence of gradingand stray capacitance on the measured reference voltage.

The surge arresters shall be capable of protecting substation equipment.

The duty cycle of Circuit Breakers to be installed in the proposed system shall be O-0.3 sec-CO-3min-CO. The Surge Arresters shall be suitable for such circuit breaker duties in the system.

12.5.3 Constructional Features

The features and constructional details of surge arresters shall be in accordance with requirement

stipulated hereunder:a) The non-linear blocks shall be of sintered metal oxide material. These shall be

provided in such a way as to obtain robust construction, with excellent mechanical andelectrical properties even after repeated operations.

b) The surge arresters shall be fitted with pressure relief devices suitable for preventingshattering of porcelain housing and providing path for flow of rated fault currents in theevent of arrester failure. Details shall be furnished in the bids along with qualitychecks.

c) The arresters shall not fail due to arrester insulator contamination.

d) Seals shall be provided in such a way that these are always effectively maintainedeven when discharging rated lightning current.

e) Outer insulators made from porcelain shall conform to requirements stipulated in Sub-chapter 3.27. Non-hygroscopic composite insulators which conform to relevantinternational standards may also be used for the outer insulator and must alsogenerally conform to the requirements of Sub-chapter 3.27.

f) Terminal connectors shall conform to requirements stipulated under Sub-Chapter3.28. The arrester housing shall be so coordinated that external flashover will notoccur due to application of any impulse or switching surge voltage up to the maximumdesign value for arrester.

g) The end fittings shall be made of corrosion proof material and preferably be

nonmagnetic.h) The nameplate shall conform to the requirements of IEC Standards incorporating the

year of manufacture.






i) The heat treatment cycle details along with necessary quality checks used forindividual blocks along with insulation layer formed across each block are to befurnished. Metalizing coating thickness for reduced resistance between adjacentdiscs is to be furnished with additional information schedule of bid proposal sheetsalong with procedure for checking the same. Details of thermal stability test foruniform distribution of current on individual disc is to be furnished.

j) The manufacturer (through the Contractor) will submit Data for rejection rate of ZnOblocks during manufacturing/operation for the past three years.

12.5.4 Fittings and Accessories

All lightning arresters shall be complete with insulating base having provision for bolting to flatsurface of structure.

The lightning arresters shall be fitted with a pressure relief device.

Surge counters shall be supplied for each single phase arrester, suitably enclosed for outdoor useand requiring no auxiliary or battery supply for operation shall be provided along with necessaryconnection.

The earth conductor from the arrester to the counter as well as the in-terminal of the counter shallbe suitably insulated or screen protected against accidental touching.

Suitable leakage current meters should also be supplied within the same enclosure. The readingof milliammeter and counters shall be visible through an inspection glass panel.

The terminals shall be robust and of adequate size and shall be so located that incoming andoutgoing connections are made with minimum possible bends. The design of the surge monitorshall be such that it is possible to tilt the surge monitor downwards by an angle of up to 45degrees from Horizontal plane.

Microprocessor based instruments for monitoring resistive current or watt-loss of the arrester shallhave to be supplied, if required.

Surge monitor consisting of discharge counters and milliammeters should be suitable to bemounted on support structure of the arrester and should be tested for IP55 degree of protection.The standard supporting structure for surge arrester should be provided with a mounting pad, forfixing the surge monitor. The surge monitor should be suitable for mounting on this standardmounting pad. Also all nuts, bolts, washers etc. required for fixing the surge monitor shall have tobe supplied by the Contractor.

Grading/corona rings shall be provided on each complete arrester unit as required. Suitableterminal connectors shall be supplied by the Contractor.


12.6.1 Type Tests

In accordance with the requirements stipulated under Sub-Chapter 3.12, the surge arrestersshould have been type tested as per IEC Standard and shall be subjected to routine andacceptance tests in accordance with IEC document. The test reports of the type tests and thefollowing additional type tests shall also be submitted for the Employer/Engineer's review.

i) Radio interference voltage test.

ii) Seismic withstand test.

iii) Contamination test.

iv) Temporary over voltage withstands test procedure to be mutually agreed)v) Each metal oxide block of surge arresters shall be tested for the guaranteed

specific energy capability in addition to the routine/acceptance test as per IEC-60099-4.






12.6.2 Acceptance Testsi) Measurement of power frequency reference voltage of the arrester units.

ii) Lightning Impulse Residual voltage on arrester units (IEC clause 6.3.2).

iii) Internal Ionisation or partial Discharge test.

12.6.3 Special Acceptance Testi) Thermal stability test on three sections (IEC Clause 7.2.2).

ii) Aging & Energy Capability test on blocks (procedure to be mutually agreed).

iii) Watt loss test.

12.6.4 Routine Testsi) Measurement of reference voltage.

ii) Residual voltage test of arrester unit.

iii) Internal Ionisation test or partial discharge test.

iv) Sealing test.v) Verticality check on completely assembled Surge arresters as a sample test on

each lot.

12.6.5 Test on Surge Monitors

The Surge monitors shall also be connected in series with the test specimens during residualvoltage and current Impulse with-stand tests to verify efficacy of the same. Additional routine/functional tests with one 100A and 10kA current impulse, (8/20 micro sec.) shall also beperformed on the Surge monitor.

12.6.6 Test on insulators

All routine tests shall be conducted on the hollow column insulators as per IEC. The followingadditional tests shall be carried out on insulators:

i) Ultrasonic test as a routine test.

ii) Pressure test as a routine test.

iii) Bending load test in 4 directions at 50% specified bending load as a routine test.

iv) Bending load test in 4 directions at 100% specified bending load as a sampletest on each lot.

v) Burst pressure test as a sample test on each lot.

12.6.7 Commissioning Tests An indicative list of tests is given below. The Contractor shall responsible for any additional tests(including the associated costs) based on specialities of the items as per the fieldQ.P./Instructions of the equipment Supplier or the Employer. The Contractor shall arrange allinstruments required for conducting these tests along with calibration certificates and shall furnishthe list of instruments to the Employer/Engineer for approval.

a) Leakage current measurement.

b) Resistance of ground connection.

12.7 Compliance with SpecificationIf the technical requirements are not met or the performance of the equipment during test do notmeet the guarantees stated in the technical particulars subject to tolerances specified in relevantIEC Standards, the Employer shall have the right to reject the faulty component or the entire






item. The Contractor shall replace the same in full compliance with the specification.


Refer to Chapter 26




13. TECHNICAL SPECIFICATION FOR 132kV XLPE CABLE




Chapter 13: 132kV XLPE Cable

Page i Kenya Power and Lighting Company Limited Substation Bidding Documents – April, 2011

Contents

13 General ............................................................................................... 3




13.4 General Requirement ................................................................................... 4

13.4.1 Conductor ........................................................................................................ 4

13.4.2 Conductor Screen ........................................................................................... 4

13.4.3 Insulation ......................................................................................................... 5

13.4.4 Insulation Screen ............................................................................................. 5

13.4.5 Water Barriers .................................................................................................. 5

13.4.6 Metallic Sheath ................................................................................................ 5

13.4.7 Oversheath ....................................................................................................... 6

13.4.8 Anti- Termite Protection .................................................................................. 6

13.4.9 Fire Resistance ................................................................................................ 6

13.5 Electrical System Design Parameters ........................................................ 7

13.5.1 Thermal Rating design parameters .......... ......... ......... ......... .......... ......... ........ 7

13.5.2 Ground thermal resistivity .............................................................................. 7

13.5.3

Continuous Ratings ........................................................................................ 7

13.5.4 Short Circuit Rating ........ .......... ......... ......... .......... ......... ......... ......... .......... ...... 8

13.5.5 Cyclic Ratings .................................................................................................. 8

13.5.6 Emergency Rating ......... ......... .......... ......... ......... ......... ......... .......... ......... ........ 8

13.6 Requirements for 132kV XLPE Cable Accessories ............. ............. ......... 9

13.6.1 Outdoor Terminations ......... ......... .......... ......... ......... .......... ......... ......... ......... .. 9

13.6.2 Gas Immersed termination.............................................................................. 9

13.6.3 Transformer Terminations .......... ......... ......... .......... ......... ......... ......... .......... ... 9

13.6.4 Straight joints .................................................................................................. 9 13.7 132kV Cable System Tests ........................................................................ 10

13.7.1 General ........................................................................................................... 10

13.7.2 Type Tests ...................................................................................................... 10

13.7.3 Schedule of Type Tests ................................................................................. 10

13.7.4 Electrical Tests .............................................................................................. 11

13.7.5 Tests on Cable components ......................................................................... 11

13.8 Routine Test Requirements for 132 kV XLPE Insulated

cable ............................................................................................................ 11

13.8.1 General ........................................................................................................... 11





Page ii Kenya Power and Lighting Company Limited Substation Bidding Documents – April, 2011

13.8.2 Voltage Test ................................................................................................... 12

13.8.3 Partial Discharge Test ................................................................................... 12

13.8.4 Dielectric loss angle ...................................................................................... 12

13.8.5 Conductor Examination ................................................................................ 12

13.8.6 Measurement of the Electrical of the Conductor ......... ......... ......... .......... .... 12

13.8.7 Overshealth Voltage withstand test ......... ......... ......... ......... .......... ......... ...... 12

13.8.8 Additional Regular Tests ........ .......... ......... .......... ......... ......... ......... .......... .... 12

13.8.9 Frequency of Tests ......... .......... ......... ......... .......... ......... ......... ......... .......... .... 13

13.8.10 Repetition of Tests ........................................................................................ 13

13.8.11 Measurement of Insulation Thickness ......... .......... ......... ......... ......... .......... . 13

13.8.12 Measurement of Insulation Concentricity ......... ......... .......... ......... ......... ...... 13

13.8.13 Measurement of Insulation Purity ......... ......... ......... ......... .......... ......... ......... 13

13.8.14 Measurement of Insulation & Screen Moisture Content ................. ......... ... 14

13.8.15 Hot Set Test fir XLPE Insulation ........ .......... ......... ......... ......... .......... ......... ... 14

13.8.16 Insulation Shrinkage Test ............................................................................. 14

13.8.17 Measurement of the Resistivity of the Semi ConductingScreens .......................................................................................................... 14

13.8.18 Measurement of Semi Conducting Screen Protrusion ..... ......... .......... ....... 14

13.8.19 Measurement of Capacitance ....................................................................... 15

13.8.20 Measurement of Crosslinking By- Product Concentractionin XLPE Cables .............................................................................................. 15

13.8.21 XLPE Material Characterisation ......... .......... ......... ......... ......... .......... ......... ... 15

13.8.22 Sample Tests ................................................................................................. 16

13.9 Routine Test Requirements for 132kV XLPE insulatedCable accessories ...................................................................................... 16

13.9.1 One- Piece Premoulded Joints and three pice Prefabricated joints ......... ......... .......... ......... ......... .......... ......... ......... .......... ......... ......... ......... 16

13.9.2 Additional Tests on One Piece joints .......... ......... ......... ......... .......... ......... ... 16

13.9.3 Commissioning Tests ................................................................................... 17

13.9.4 High Voltage AC Filed Acceptance Test ......... .......... ......... ......... .......... ....... 17 13.9.5 Additiional Tests ............................................................................................ 17

13.10 Marking........................................................................................................ 18

13.11 Dispatch ...................................................................................................... 18

13.12 Site Survey .................................................................................................. 18

13.13 Crossing with other utilities and interference with pipelines ............ ..... 19






13 GeneralThis Chapter covers the technical requirements of single core XLPE insulated copper cablesand their accessories for operation at 50Hz ac voltages of 76.2kV between any conductorand sheath or earth, 132kV between phase conductors and maximum sustained powerfrequency voltage between phase conductors of 145kV.

The specification stipulates the minimum requirements for 132kV single core XLPE insulatedcopper cables and their accessories acceptable for use in the company and it shall be theresponsibility of the Manufacturer to ensure adequacy of the design, good workmanship andgood engineering practice in the manufacture of the cables for KETRACO.

Equipment shall generally be in accordance with requirements under Chapters 2 and 3.

The relevant Technical Data Sheets in Chapter 26 shall be completed in full to verify orclarify compliance or otherwise with these Employer requirements. All data will be filled outin the forms.



The Plant shall be capable of operation under the general electrical parameters as specifiedin Sub-chapter 3.6.2.


The Plant shall be capable of operation under the atmospheric conditions as specified inSub-chapter 3.6.1.

It is jointly the Contractors and manufacturer s responsibility to be familiar with any otherclimatic and physical conditions pertaining to the specific sites as defined in Chapters 1-3and to allow for all conditions in designs.

Particular attention should be paid in the design of all equipment to ensure that there is nodamage to working parts or insulation through the ingress of dust, insects, vermin which areprevalent for long periods in the year. All orifices and air vents should be covered by easily

replaceable weather resisting, fine mesh wire where practicable.


All equipment shall be designed, constructed and tested in accordance with requirements ofthe latest version of the standards specified herein except to the extent explicitly modified inthis specification:


IEC 60840: Power cables with extruded insulation and their accessories for rated voltagesabove 30kV (Um = 36kV) up to 150kV (Um = 170kV) – Test methods and requirements






IEC 60228: Conductors of insulated cables.

13.4 General Requirement

The cable shall comply with the requirements of IEC 60840, IEC 60228 plus any additionalrequirements specified hereafter.

The cable shall be designed for reliable service life of at least 40 years.

All materials used shall be compatible and suitable for the continuous operating temperatureof the cable of 90°C and short circuit temperature of 250°C (5 seconds duration).

13.4.1 ConductorConductors shall be stranded, annealed, high conductivity copper. The copper wire beforeshaping shall be smooth, uniform in quality, free from scale, inequalities, spills, splits andother defects and should comply with the requirements of international application IEC60228.

The term „annealed signifies that the wire before stranding is capable of at least 15 per centelongation without fracture, the test piece being not less than 150mm and not more than300mm.

When made of from shaped wires the conductor shall be clean and uniform in size andshape and its surface shall be free from sharp edges and unless otherwise approved shall

be taped with a layer of conducting a layer of conducting or semiconducting material..Not more than two joints shall be allowed in any of the single wires forming each length ofconductor and no joint shall be within 300mm of any other joint in the same layer. The

jointing of the wires shall be by brazing, silver soldering cold welding or electrical welding.No joint shall be made in the wire after it has been formed up into the required length.

The conductor will be water blocked to meet the requirements of IEC 60840, using waterblocking tapes and / or yarns. The use of water blocking powder on its own is not permitted.

13.4.2 Conductor Screen

A conductor screen shall be used to provide a smooth interface between the conductor andthe cable insulation. A suitable semiconducting binder tape will be applied over theconductor to prevent the extruded screen from falling between the interstices of theconductor strands.

The semi-conducting screen will have a spot minimum thickness of 1.0mm

The conductor screen will be made from semiconducting crosslinked polyethylene

(XLPE) using either acetylene black or carbon black material and will be applied as part of atriple extrusion process.

The conductor screen shall be extruded and consist of a black, semi-conducting thermosetmaterial fully compatible with the conductor and extruded insulation. The outer surface of thesemi-conducting screen shall be super smooth, cylindrical and firmly bonded to the overlyinginsulation.






The extruded conductor screen shall be applied in the same operation as the insulation andbe fully bonded to the insulation

13.4.3 Insulation

The insulation shall be cross-linked polyethylene (XLPE) conforming to the requirements ofIEC 60840.

The insulation shall be an extruded cross-linked polyethylene (XLPE) material forming aconcentric dielectric surrounding the conductor.

The use of insulation based on pure LDPE is preferred to the use of insulation based onCo-polymer.

The materials for the manufacture of 132kV cables shall be delivered in clean bulkcontainers.

The preferred manufacturing process is the vertical continuous vulcanisation (VCV) linehowever cable manufactured with either MDCV or CCV lines will also be considered. Thecable shall be manufactured using low viscosity, ultra clean grades of material.

Every effort is to be made by the manufacturer to ensure the purity of the insulation extrudedon the cable core. The preferred method for material handling is the use of fully integratedand enclosed material filtration and compounding facilities that are connected directly to theextrusion line. Frequent sampling during compound manufacture should take place.

The insulation shall be applied by extrusion and cross-linked to form a compact andhomogeneous layer.

The colour of the insulation shall be such that it is easily distinguishable from the screeningmaterials.

13.4.4 Insulation Screen

The insulation screen shall be extruded and consist of a black, semiconducting thermosetmaterial fully compatible with the extruded insulation. The interface between the insulationand the semiconducting screen shall be super smooth, cylindrical and firmly bonded.

13.4.5 Water Barriers

The core shall be taped overall with semiconducting cushioning tapes to prevent possiblemechanical damage of the cable core caused by thermal expansion during normal operationof the cable.

Provision should be made to prevent the longitudinal penetration of water along the interfacebetween the cable core and the metallic sheath by the application of suitable water swellabletapes applied over the cable core.

13.4.6 Metallic Sheath

The sheath is required to fulfil the following requirements;

To provide a radial watertight barrier to the ingress of moisture into the extruded cablecore.






Provide low resistance path for cable charging current

Provide protection against minor accidental damage caused by third party interferencewith the cable during installation or service

Be capable of sustaining the specified earth fault currents for the time stipulated bythe user.

The water impervious sheath shall consist of a seamless and continuously extruded tube oflead alloy. The lead alloy used for the sheath shall be alloy 1/2C. A thin layer of bitumenshall be applied over the sheath.

Lead alloy sheath of best quality metal, free from pinhole flaws and other imperfections shallbe tightly extruded over the water blocking layer.

The minimum thickness at any point shall not fall below the specified nominal thickness bymore than 0.1mm or 5% of the nominal thickness.

For the purpose of increasing the total short circuit current rating of the cable, a copper wirescreen of suitable cross sectional area may be applied between the core bedding layer andthe lead sheath. A copper tape shall be applied directly over the copper wires in an oppositelay to the lay of the copper wires, to ensure equal current sharing in the copper wire screen.

A suitable binder tape shall be applied over the copper wire screen.

13.4.7 Oversheath

The cable serving shall be robust enough to prevent unnecessary damage during installationand shall insulate the cable from earth.

The outer covering shall preferably be of medium density polyethylene, except for theclosing sections that enter buildings, which shall be of a low smoke, zero halogen material(LSOH).

The minimum average thickness and minimum thickness at a point shall comply with IEC60840 and not less than the value stated in the schedule.

An outer conductive coating (graphite coating or extruded layer) shall be applied to thecovering to serve as an electrode for the voltage test on the outer covering .

13.4.8 Anti- Termite Protection

All cables installed in concrete troughs within a substation shall have suitable anti-termiteprotection, to be approved by KETRACO

13.4.9 Fire Resistance

All cable sections installed in air will have an oversheath with a fire performance thatconforms to the requirements of,

IEC 60332-1 (Fire) IEC 60332-3A (Fire) IEC 61034 (Smoke) IEC 60754 (Minimal Halogen)






Ideally, oversheath materials will also have an oxygen index of less than 30% and atemperature index of greater than 260

13.5 Electrical System Design ParametersThe standard sizes and characteristics of the cables shall be as follows:

The following electrical design parameters shall be used in the design of the 132kV cablecircuit.

Nominal System voltage: 132kV

Max. / Min voltage variation +5% / -5%

Loading capability of the 132kV cable circuits 90 MVA

Short circuit level 31.5kA for 1sec

13.5.1 Thermal Rating design parameters

The environmental parameters shall be as advised in clause 13.2

The following installation parameters should be used unless otherwise stated in the projectspecification

Depth to the top of cable 1100mm

Phase spacing: 250mm

Circuit Spacing: thermal independence

13.5.2 Ground thermal resistivity

Ground conditions around the Kindaruma region are made up of red loamish soils.

All cable circuits are to be installed using a selected sand backfill that has a guaranteeddried-out TR of no greater than 2.7Km/W. The contractor will advise the guaranteed dried-out TR of the selected sand backfill that they choose.

13.5.3 Continuous Ratings

Continuous rating calculations are to be performed in accordance with IEC 60840.

Contractors are required to state clearly the value of ac resistance used for XLPE cableconductors and justify the value used.

Contractors are required as part of their site survey works to identify any utilities in closeproximity to the new cable circuit that may derate the cable circuit and to calculate the

derating effect and propose a solution to negate this effect.






Cable rating calculations shall be submitted along with the offer based on the data providedunder Clause 13.5.1. The calculations shall be reconfirmed and approved after the siteinvestigations and before the

manufacture.

13.5.4 Short Circuit Rating

Short circuit ratings must be calculated using the adiabatic methods described in IEC 60949 .Short-circuit levels for the different system voltages are as follows;

System Voltage Short Circuit level

132kV 31.5 kA for 1 second

13.5.5 Cyclic Ratings

Cyclic ratings should be calculated in accordance to IEC 60840

13.5.6 Emergency Rating

Emergency or overload rating should be calculated in accordance with IEC 60840

13.6 Calculation of Induced Voltages

13.6.1 Effects on auxiliary cables

Contractors are required as part of site survey works identify any existing cooper conductortype auxiliary cables e.g. pilot & telephone cables that run in close proximity to the newcables circuits and calculate the induced voltages that could be imposed on the insulatedcores of the auxiliary cable.

13.6.2 Effects on Pipelines

Contractor are required as part of their site survey works to identify any metallic pipelinesrunning in close parallel proximity to the new cable circuits and to,

i) Calculate any induced voltages that could be imposed on the pipeline, both understeady state and fault conditions.

ii) Determine the influence of any such induced voltages on the cathodic protectionsystem used on the pipeline






13.7 Calculation of other Cable System Parameters

i) Positive, Negative and zero sequence impedances and,

ii) Thermal time constant (for the setting of cable overload protection).

13.8 Requirements for 132kV XLPE Cable Accessories

13.8.1 Outdoor Terminations

Termination insulators must be manufactured from Porcelain materials, all materials shall befully factory tested during production. In accordance with IEC 60815 the pollution levelspecified is „very heavy .

The stress control method must allow for the thermal expansion of the cable and thetenderer must state how this is achieved. The sealing ends shall be filled with high viscositypolyisobutylene, silicone oil, or equivalent and expansion devices shall be provided wherenecessary.

Corona shields and arcing rings or horns shall be provided at the top of each open typetermination and a horn or ring at the base. The base itself shall be insulated from supportingsteelwork by mounting upon porcelain pedestal type insulators.

13.8.2 Gas Immersed termination

Gas immersed terminations at the SF6 switchgear shall comply with the requirements of thelatest version of IEC 60859. The Supplier shall demonstrate that terminations meet themechanical loading of IEC60859. The terminations may be of "dry type" or “wet type”construction, containing an epoxy resin insulator and an elastomeric stress cone. Theinsulator shall have a blind-ended construction to eliminate the possibility of SF6 gas leakinginto the cable termination via the conductor connection.

The cable glands of the sealing ends shall be insulated from the SF6 switchgear, andtransformers

13.8.3 Transformer Terminations

The terminations may be of "dry type" or “wet type” construction, containing an epoxy resininsulator and an elastomeric stress cone. The insulator shall have a blind-endedconstruction to eliminate the possibility of transformer oil leaking into the cable terminationvia the conductor connection.

The cable glands of the sealing ends shall be insulated from the transformers.

The cable manufacturer will liaise fully with the transformer manufacturer to ensure that thecable sealing ends will interface correctly with the transformer.

13.8.4 Straight joints

The conductor connection will be made using a compression ferrule.

The following types of joint only will be considered for offer;






Premoulded One – Piece Extrusion Moulded Prefabricated Three – Piece

The design of joint will accommodate insulation retraction and expansion.

The design of joint will include an internal partial discharge (PD) sensor.

The joint shall be provided with a copper joint shell suitable for a metallic seal to theextruded metallic sheath of the cable.

Cable joints buried in the ground shall be enclosed in a fibreglass casing and the spacebetween the joint and casing shall be completely filled with bituminous compound ofapproved grade. Alternative methods of insulating and protecting the joint e.g. heat shrinksleeve, rubber tape, may be offered subject to demonstration of development tests and typetests.

13.9 132kV Cable System Tests

13.9.1 General

132kV cable and cable accessories shall be tested together as a complete system for typetest and prequalification test purposes. Commissioning tests will inherently test thesecomponents as a complete system.

13.9.2 Type Tests

The appropriate type tests specified in this clause shall be made before the manufacturersupplies on a general commercial basis the type of cable described in this specification inorder to demonstrate satisfactory performance requirements.

These tests excepting those which are also required as additional regular tests need not berepeated once they have been performed successfully, unless alterations are made to cabledesign or materials which might affect the performance.

The accessory manufacturer must demonstrate by type test approval tests on the specificcable that any joint or termination that it is intended for use with the cable supplied for aspecific contract is compatible with that cable.

Tests are required to demonstrate satisfactory performance characteristics of the basicaccessory design.

Designs suitably tested may be used for applications where the electrical design stressesare the same or lower than those tested.

Type Testing will be in full accordance with IEC 60840.

13.9.3 Schedule of Type Tests

The type tests shall comprise electrical tests on complete cable and the appropriate tests oncable components.

The electrical tests shall be carried out in sequence on one sample of cable. The bendingtest shall be included in this sequence of tests to check that the electrical properties of the

cable after bending are satisfactory.






13.9.4 Electrical Tests

The normal sequence of tests shall be:

Bending test followed by partial discharge test (IEC Publication 60840)

Tan delta measurement (IEC Publication 60840) Heating cycle voltage test, followed by partial discharge measurement (IEC

Publication 60840)

Impulse withstand test followed by power frequency voltage test (IECPublication

60840)

An AC withstand test on cable only of 5Uo for 1 hour.

13.9.5 Tests on Cable components

The following tests should be completed on the cable components:

Measurement of thickness of insulation Measurement of insulation concentricity Measurement of insulation purity Measurement of moisture content in extruded insulation and screens Hot set test for XLPE insulation Shrinkage test

Measurement of resistivity of semiconducting screens Measurement of screen protrusion Tests for determining the mechanical properties of the insulation before and

after ageing (IEC Publication 60840) Ageing tests on pieces of complete cable to check compatibility of materials

(IEC Publication 60840) Impact test on metallic sheath Water penetration test (IEC Publication 60840)

13.9.5.1 Add itional Tests for Accesso ries

Upon completion of the Type Test the joint will be fully dismantled and examined for anysigns of distress or disruption not detected by the Type Test.

The sheath insulation used to enclose the joint will be subjected to the following tests;

Impulse tests in accordance with Engineering Recommendation C55/4„Insulated Sheath Power Cable Systems from the Electricity Council, UK.

Water penetration tests in accordance with CENELEC HD 632 S1:1998PART 2, section 6.2.9 (page 2-61).

13.10 Routine Test Requirements for 132 kV XLPE Insulated cable

13.10.1 General

The following tests shall be carried out on every dispatch drum of cable, to check that thewhole of each length complies with the requirements.






Voltage test Partial discharge test Dielectric loss angle

Conductor examination Measurement of electrical resistance of conductor Oversheath voltage withstand test

13.10.2 Voltage Test

The voltage test shall be conducted in accordance with the IEC publication 60840.

13.10.3 Partial Discharge Test

The partial discharge test shall be conducted in accordance with IEC Publication 60840.Measurements shall be made at least after initial voltage energisation and at the end of the

specified test period.

13.10.4 Dielectric loss angle

This shall be measured at 1.5Uo. The value shall be less than or equal to 0.0005.

13.10.5 Conductor Examination

Compliance with the requirements of IEC Publication 60228 for conductor construction shallbe checked by inspection and measurement.

13.10.6 Measurement of the Electrical resistance of the Conductor

The measurement of the electrical resistance of the conductor shall be made in accordancewith IEC Publication 60840. The measured resistance of the conductor should comply withthe value specified in IEC Publication 60228.

13.10.7 Overshealth Voltage withstand test

Each drum length of completed cable shall withstand a voltage of 25kV DC for one minutebetween the metal sheath and the external conducting surface

13.10.8 Additional Regular Tests

The following tests shall be made on each completed cable length (or dispatch drum length):

Measurement of thickness of insulation Measurement of insulation concentricity Measurement of insulation purity Measurement of moisture content in extruded insulation and screens Hot set test for XLPE insulation Shrinkage test

Measurement of resistivity of semiconducting screens Measurement of screen protrusions






Measurement of capacitance Measurement of crosslinking by product concentration in XLPE cables XLPE Material Characterisation

13.10.9 Frequency of Tests

Additional tests 1, 2, 3, 4, 5, 6, 8 and 10 will be performed on both ends of every dispatchdrum.

13.10.10 Repetition of Tests

If the samples from any length selected for the tests should fail in any of the tests in thisclause, further samples shall be taken from two further lengths of the same batch andsubjected to the same tests as those in which the original sample failed. Should bothadditional cables pass the tests, the other cables in the batch from which they were takenshall be regarded as having complied with the specified requirements. Should either fail, thisbatch of cables shall be regarded as having failed to comply.

Further re-sampling and testing should then become a matter for negotiation between theuser and the manufacturer.

13.10.11 Measurement of Insulation Thickness

The thickness of the insulation shall be measured in accordance with IEC Publication 60840.

The minimum thickness of the insulation measured at any point shall not fall below thespecified minimum average thickness by more than 10% of the minimum average thickness.

13.10.12 Measurement of Insulation Concentricity

A 50mm sample shall be taken from the cable core. The sample shall be cut into wafersapproximately 12.5mm thick and viewed under magnification. The samples shall beexamined at six points equally spaced around the cable with one of the points correspondingto the point of minimum insulation thickness, tmin. The maximum allowable deviationbetween the thickness at the point of minimum thickness, tmin, and the maximum measuredthickness value, tmax, shall be less than 8% of the measured minimum average thickness.

tmax - tmin < 0.1 x minimum average thickness

13.10.13 Measurement of Insulation Purity

A sample approximately 50mm long shall be taken from the cable core. This sample shall becut into 25 wafers approximately 2mm thick. The entire area of each wafer shall beexamined with a minimum 15 power magnification microscope by transmitted light.






13.10.19 Measurement of Capacitance

The capacitance of the completed cable shall be measured between the conductor and themetallic sheath.

The measured value shall not exceed the nominal value specified by the manufacturer bymore than 8%.

13.10.20 Measurement of Crosslinking by- Product Concentration in XLPE Cables

Excessive by-product concentration adversely affects the electrical performance of the cableand could diffuse out of the cable core and pressurise external cable protection/accessories.

The test is to be conducted using TGA (Thermo-Gravimetric Analyser) apparatus. A 20mginsulation sample is required. The test is to be conducted for 30 minutes at 150oC. The %loss of weight of the sample is to be recorded. Five samples are to be taken, the result beingthe average of five tests.

The cable is at a stable by-product level if:

The total weight change of the test sample after a period of 30 minutes is less

than 1.25% of the original sample weight.

The rate of change is less than 0.14% minimum in the first five minutes of the

test.

Between the time period of 15-30 minutes the average rate of change ofsample weight does not exceed 0.01%.

13.10.21 XLPE Material Characterisation

All insulating and semi-conducting XLPE materials used to manufacture all cables to besupplied into Kenya as part of this contract shall be identical to those used to manufacturethe Type Test Cable. In order to demonstrate compliance, the Contractor shall „finger printsamples from the Type Test Cable and all cables manufactured under the contract. Thecharacterisation shall include the following methods;

I. Fourier Transform Infrared Spectroscopy (FTIR) to characterise the insulatingpolymer.

II. Differential Scanning Calorimetry to characterise the material processing.

III. Thermogravimetric Analysis (TGA) on the incoming semiconducting material to

characterise the carbon black content.

IV. Cleanliness measurement on the incoming insulation material.

V. Thermogravimetric Analysis (TGA) on the incoming semiconducting material to

characterise the carbon black content.






Test i) and ii) will be conducted on both ends of every despatch drum. Tests iii), iv) and v)will be conducted on every batch of incoming material.

13.10.22 Sample TestsThe sample test requirements of IEC 60840 shall be performed with the followingexceptions;

Tests that are already specified under section 13.8 .8 „Additional Regular Tests shall not

be repeated as a Sample Test.

The lightning impulse followed by power frequency voltage test shall be replaced with just

a power frequency voltage test of 5Uo for 1 hour. The frequency of this test shall be on

one 20m sample from every extrusion run or every 6km, whichever is the lower.

13.11 Routine Test Requirements for 132kV XLPE insulated Cable accessories

13.11.1 One- Piece Premoulded Joints and three piece Prefabricated joints

The insulation and screening material used for all one-piece premoulded joints and rubberstress cone components of three-piece prefabricated joints shall be identical to those usedto manufacture the Type Test accessories. The characterisation of the insulation andscreening material shall include

Fourier Transform Infrared Spectroscopy (FTIR) to characterise the insulatingpolymer.

Cleanliness measurement on the incoming insulation material

DLA measurement of insulation at 90ºC. Thermogravimetric Analysis (TGA) on the incoming semiconducting materialcharacterise the carbon black content

The above tests will be carried out on one joint in every ten manufactured for the contract.

The following, additional tests, will be conducted on every one piece joint or rubber stresscone;

HV Withstand Test at 2Uo for 30 minutes. Partial Discharge Measurement at 2Uo. Discharge to be < 10pC with background

noise level of 2pC

13.11.2 Additional Tests on One Piece joints

The following, additional tests, will be conducted on every one piece joint only;

Mechanical stretch of each rubber component over a mandrel equal in diameter tothe Contractors site assembly mandrel.

Resistance of outer semi-conducting screen < 20kohms.






Cross-bonding configuration checks

13.12 Marking

The following information will be clearly printed with indelible ink on the semiconductingXLPE screen of every cable;

„132kV XLPE Cable – KETRACO – Cable No.XXXXX - Date

The oversheath should be legibly embossed along its length with the following information:

„132000V Electric Cable, (Manufacturer), (Year of Manufacture) PROPERTY OF KETRACO

The embossed letters and figures shall be raised and consist of upright block charactersalong two or more lines, approximately equally spaced around the circumference of thecable.

For both the semiconducting XLPE screen and the oversheath, the maximum size of thecharacters shall be 13 mm and the minimum size not less than 15 per cent of the nominal orspecified external diameter of the cable or 3 mm, whichever is the greater.

For both the semiconducting XLPE screen and the oversheath, the spacing between the endof one set of embossed characters and the beginning of the next on the legend shall notexceed 150 mm. Any additional information embossed on the sheath (e.g. theManufacturer s name) shall not affect the spacing between repetitions of the legend.

13.13 Dispatch

Both ends of the cable shall be rendered fully watertight by fitting a metallic end cap and apulling eye which are plumbed to the cable metallic sheath. The pulling eye shall be directlyconnected to the conductor and be capable of withstanding a tensile load of 100N/mm² ofconductor area up to a maximum of 6 tonnes. When requested by the user, pulling eyes

shall be fitted to both ends of the cable.

The cable shall be dispatched on a drum of suitable construction of minimum hub diameter20D (where D is the overall diameter of the cable). The drum shall be fully enclosed byeither adjacent fitting wooden battens or continuous metallic cladding.

13.14 Site SurveyThe Contractor shall carry out, at his own expense, moisture content, water table level, andsoil thermal resistivity tests along the 132kV cable route and such other tests as he may

consider necessary, sufficiently in advance of the manufacture of any cable, to satisfyhimself that the conditions on site and his proposed arrangement of cables and method ofinstallation are such that the maximum current carrying capacity can be maintained. If the






Contractor considers that the conditions and the proximity to other power cables, spacingand method of installation are likely to reduce the maximum current carrying capacity belowthe declared value he shall immediately notify KETRACO as to what the maximum currentcarrying capacity would be under these conditions and shall not proceed with the work on

that portion of the route affected until KETRACO has given its permission.

Within a reasonable time after the Contract has come into force, the Contractor shall agree afinal route with KETRACO and confirm the arrangements.

The Contractor shall open trial pits at approved positions, to determine the most suitabledetailed route and position for the trenches. The width of trial pit shall be sufficient todetermine the cable route, but not smaller than that of cable trench.

All routes shall be defined precisely, and shown in drawings at a scale of 1:500. The stablestructures shall be indicated clearly as well as distances. The crossings with roads andunderground installation shall be shown. Joint locations shall be identified clearly andsufficient section views shall be provided where necessary. The dates of installation of cable

joints, cable drum serial numbers, name of jointers, shall be i ncluded in the “AS -BUILT”drawings. Cable section lengths shall also be given.

All drawings shall be subject to KETRACO s approval.

The quantity of cables, accessories etc. to be supplied shall be based upon this survey. Theprogramme for route survey works shall be agreed upon with KETRACO prior tocommencement of works.

13.15 Crossing with other utilities and interference with pipelines

In case of crossings with the other installation the following shall be observed:

The service authorities may imply additional requirements (mechanical protection,etc.) through a work permit procedure. The Contractor shall comply with thisrequirement, and it is considered included in the Contract Price.

In cases where other heat sources are to be crossed special attention shall be paid

to cable current rating calculations, and additional measures shall be applied

Details of the typical crossing arrangements are given in Section VI, Appendix A. KETRACOstandards shall be followed for working in the vicinity of power cables.

At crossings with existing installations the new cable shall be preferably installed beneath,always taking into account the current rating requirements. If necessary, the phase spacingcould be increased at the crossing point.

After opening existing installations and before cable laying and installation, the sketch of thefinal arrangement shall be approved.

Each crossing point shall be clearly marked with the route markers, after backfilling.






During installation, when crossing other heat sources, or laying at depths deeper than 1.1 mat the crossings or such similar conditions, the Contractor shall maintain the specified rating,either by application of the special stabilised backfill or by increasing the phase spacing. For

every situation the arrangement with relevant calculations shall be submitted to KETRACOfor approval, prior to installation


Tests shall be in accordance with applicable international standards and provisions of Sub-chapter 3.12.


If the technical requirements are not met or the performance of the equipment during test donot meet the guarantees stated in the technical particulars subject to tolerances specified inrelevant IEC Standards, the Employer shall have the right to reject the faulty component orthe entire item. The Contractor shall replace the same in full compliance with thespecification.


Refer to Chapter 26



Volume II – Section VI: Employer’s Requirements: Contract 16 - 132/33Kv Substations andBays

Chapter 13: Line Traps





14. TECHNICAL SPECIFICATION FOR COPPER BUS TUBES,

CONDUCTORS AND ACCESSORIES




Chapter 14: Busbars, Conductors and Accessories


Contents

14 BUSBARS TUBES , CONDUCTORS AND ACCESSORIES .............. 1

14.1

General .......................................................................................................... 1

14.2 Particulars of Electrical System ............. ............. ............. ............. ............. . 1


14.4 Standards, Units and Language ............. ............. ............. ............. ............. . 1


14.5.1 General ............................................................................................................. 1

14.6 Copper tubes ................................................................................................ 2

14.6.1 General ............................................................................................................. 2

14.6.2 Materials and Construction............................................................................. 2 14.6.3 Dimensions ...................................................................................................... 2

14.6.4 Electrical and Mechanical Properties ......... .......... ......... ......... ......... .......... ..... 3

14.6.5 Mechanical Properties .......... ......... ......... .......... ......... .......... ......... ......... .......... 3

14.7 TESTS AND INSPECTION ............................................................................ 3

14.8 Shield Wire .................................................................................................... 3

14.9 Insulators ...................................................................................................... 3

14.9.1 General ............................................................................................................. 3

14.9.2 Dead-End and Suspension Type Insulators ......... ......... .......... ......... ......... .... 4

14.9.3 Post-Type Insulators ......... ......... ......... .......... ......... .......... ......... ......... ......... .... 5

14.9.4 String Insulators .............................................................................................. 5

14.9.5 Accessories ..................................................................................................... 6

14.10 Testing and Commissioning ....................................................................... 6

14.10.1 Tests on the Switchyard on Site ......... .......... ......... ......... .......... ......... ......... .... 6


14.12

Technical Data Sheet .............. ............. ............. ............. ............. ............. ..... 6






14 BUSBARS TUBES, CONDUCTORS AND ACCESSORIES

14.1 General

This Chapter gives specifications for conductors, accessories and hardware to be used on thebusbars to be installed in the outdoor yards of the substations under this project.

Generally, the busbars shall be designed to achieve the desired basic insulation levels in thegeographic and meteorological conditions as specified in Chapter 3: General TechnicalSpecifications after applying the relevant de-rating factors for high altitude as per IEC Standards.

The supply shall comprise all apparatus and requisite accessories, conductors, insulators,clamps and connections and earth wires. Steel structure and concrete foundations for thestructures are part of the civil engineering works and are specified in Chapters 23 and 24: CivilWorks and Steel Structures respectively.

Material and workmanship throughout shall be of best quality and in accordance with acceptedmodern practice. The design shall be such that installation, replacement and general operationand maintenance may be safely undertaken with a minimum of time. Liberal factor of safety shall

be used throughout the design.




The Plant shall be capable of operation under the atmospheric conditions as specified in Sub-

chapter 3.6.1. It is jointly the Contractors and manufacturer’s responsibility to be familiar with any other climaticand physical conditions pertaining to the specific sites as defined in Chapters 1-3 and to allowfor all conditions in designs.


14.4 Standards, Units and Language All equipment shall be designed, constructed and tested in accordance with requirements of thelatest version of the standards specified below except to the extent explicitly modified in thespecification and shall be in accordance with the requirements in Chapters 2 and 3.

As further specified within this Chapter



14.5.1 General All components, all equipment as well as the total plant shall be suitable for operation outdoorsspecifically under these conditions and in general under sub-tropical conditions at altitudes of upto 2200m above sea level, to the conditions stated in Sub-chapters 14.2 and 14.3 and shall






14.6.4 Electrical and Mechanical Properties

The copper tubes shall be of electrolytic tough pitch high conductivity material (Cu-ETP)with the following properties as per BS EN 13600:

Condition Volume Resistivity at

20°C (Ωxmm²/m), max

Conductivity

(%)R290 0.01786 96.6

*expressed as % of the standard value for annealed high conductivity copper as laiddown by the International Electrotechnical Commission. Copper having a volumeresistivity at 20°C of 0.017 241μΩm is said to have a conductivity of 100% IACS(International Annealed Copper Standard) .

14.6.5 Mechanical Properties

The minimum and maximum tensile strength of the copper tubes shall be 290N/mm² and360N/mm² respectively as per BS EN 13600.

14.7 TESTS AND INSPECTION

The copper tubes shall be tested in accordance with BS EN 13600 and the requirements of thisspecification. It shall be the responsibility of the manufacturer to perform or to have performed allthe relevant tests.

Certified true copies of previous test reports by the relevant International or National

Testing/Standards Authority of the country of manufacture (or ISO/IEC 17025 accreditedlaboratory) shall be submitted with the offer for evaluation (all in English Language). A copy ofaccreditation certificate for the laboratory shall also be submitted.

Copies of test reports to be submitted shall include dimensions, tensile strength and electricalresistivity tests. The Manufacturer’s Declaration of Conformity to the reference standard shallalso be submitted.

14.8 Shield Wire

The stranded steel conductor to be supplied shall conform to the requirements of IEC 62219 orequivalent standards, and to the characteristics described Chapter 26.

14.9 Insulators

14.9.1 General

The insulators shall be of high impact strength, glazed, wet process porcelain type conforming tothe requirement of IEC 60383, IEC 60305, IEC 60471, IEC 61284 and other relevant IEC or otherinternationally accepted Standards. The insulators shall be made of Wet process homogenousporcelain. Glass insulators shall not be accepted.

Alternatively, hydrophobic composite insulators conforming to the requirements of IEC 60383,IEC 60437, IEC 61109 and other relevant internationally accepted Standards such as AS1154and AS4435 may be used.

Each insulator shall be marked with the initials or trademark of the manufacturer and with theguaranteed electromechanical strength of each insulator. All markings shall be plainly legible anddurable.






Porcelain insulators shall be glazed in a uniform shade of brown, free of such imperfections asblisters and burns.

The insulators shall be free of laminations, cavities or other flaws affecting the mechanical andelectrical strength, and shall be well vitrified, tough and impervious to moisture

In general the contours of the metal and porcelain parts shall be such as to eliminate areas orpoints of high electrical flux concentration. All surfaces of metal parts shall be smooth with noprojecting points or irregularities.

All ferrous material that is not made of stainless steel shall be hot-dip galvanised in accordancewith BS 729 or equivalent International Standards.

The required leakage distance shall be chosen carefully to avoid designs in which skirts are me-chanically fragile.

Minimum factors of safety shall be:

For complete insulators based on electro-mechanical failing load test (IEC 60383) 2.5

For insulator metal fittings based on elastic limit2.5

14.9.2 Dead-End and Suspension Type Insulators

The entire exposed surface shall be glazed and free from imperfections. The insulators shallhave clevis and tongue fittings, securely connected to insulators.

The design of the insulators shall be such that breakage of the porcelain cannot materially affectthe mechanical strength of the insulators.

Dead-end/tension and suspension-type insulators for insulator assemblies shall comply with therequirements of IEC Standards and/or other internationally accepted Standards such as DINVDE standards. The creepage distance of the assembly shall be minimum 31 mm/kV line to

ground.The insulator shall be of modern fog-type design, embodying deeper outer skirts and shallowinner grooves. The Contractor shall prove, to the satisfaction of the Engineer, that thecontamination collection properties of the insulator unit are 50-60% of the standard 254x146 mmdisc.

The insulator assembly shall be of single string. The string insulator units shall comply with theprovisions of IEC 60120, IEC 60305 and IEC 60372. The type of insulator and the characteristics ofthe discs and the number of discs per string shall be chosen according to the electrical andmechanical requirements

Tests shall include all applicable tests specified in IEC and/or DIN VDE standards. Each insulatorshall also be subject to a tension proof test at the minimum load of half the mechanical andelectrical strength of insulators.

For verification of design, ten insulator units shall be selected at random from each lot, and shallbe tested for thermal mechanical performance in accordance with the latest version of IEC60575, except temperature variations, which shall be from -5 to 50 °C.

The criteria for acceptance of the insulators shall be the following:

The results of the performance tests shall match the results of ordinary electromechanicalor mechanical failing load tests. Thus, the specified electromechanical or mechanicalfailing load that applies to the ordinary electromechanical or mechanical failing load testshould be reached also in the performance tests.

Fracture pattern shall not change. Electrical puncture should not occur before reaching the maximum load and the ultimate

fracture.






The quality index Qs should be equal to or greater than the acceptance constant K toreach the requirements of the test. The acceptance constant K shall be three for a samplesize of ten insulators. The quality index is defined by:

S

RsRQs

R = Mean value of the testRs = Specified electromechanical or mechanical failing load (rated load value)S = Standard deviation

Characteristics of the dead-end and suspension type insulator are given in Chapter 26.

The socket shall be of galvanised malleable cast iron or ductile cast iron and the pin of galvanisedsteel.

Ball and socket connections shall be provided with cotter pins, which effectively lock the connectionagainst accidental uncoupling without detracting from its flexibility. The cotter pin shall be ofstainless steel or bronze.

Socket and pin shall be of such design that they will not yield or distort under the specified

mechanical loading in such a manner as to add undue stresses to the porcelain shells.14.9.3 Post-Type Insulators

The insulators shall be of outdoor, solid core, station-post type. They shall conform as a minimumto the applicable requirements of IEC 60168, latest edition, and other IEC recommendations orequivalent standards. The post insulators shall be dimensioned in accordance with the latestaddition of IEC 60273. They shall comprise fully interchangeable units of either the pedestal orsolid core cylindrical type and shall be designed so that they can be used either upright or inverted.

The maximum forces encountered during a full short circuit plus own weight of insulators andconnected equipment such as clamps and conductors/tubes shall not exceed the maximumcantilever for the insulator.

The radius of the conductor's grooves must bear such a ratio to the conductor radius that anabrasive contact be produced on the current-carrying connector components.

The bearing of the conductor in the support clamps should be thermally stable friction bearings oflow friction coefficient. A permanent and reliable transmission of charging current to the supportmust be ensured.

The deflection angle in the suspension clamps must be 8 degrees in all directions. Expansion inthe expansion clamps must not be impeded. In case the provided expansion is exceeded, thelocking device must prevent the conductor from falling out of the suspension clamp.

The maximum force encountered during normal service (own weight + wind load + switching loadof insulator and connected equipment) shall not exceed 40% of the maximum cantilever strength.

IEC 60865 shall apply.Porcelain shall be manufactured in wet process and shall be one piece, non-porous,homogenous and free from cavities or other flaws. The glazing shall be uniform in brown colourand free from blisters, burns and other defects, and shall meet all applicable requirements of IEC60273. The characteristics are described in Chapter 26.

The metal parts shall be designed to transmit the mechanical stresses to the porcelain bycompression and to develop maximum and uniform mechanical strength of the insulator.

14.9.4 String Insulators

For connecting the incoming/outgoing overhead lines to the substation switchyard, string

insulator assemblies on the dead-end gantries shall suspend the respective conductors. Theyshall be of cap-pin type, porcelain string insulator sets, assembled from insulator units. Thespecific creepage distance shall be at least 2.5 cm/kV (related to the max. phase to earthvoltage, as per IEC 60071/2). The insulators shall be assembled with all necessary bolts and






fittings. The electrical and mechanical design shall comply with relevant IEC recommendations.

14.9.5 Accessories

For all accessories as clamps, connections, etc., care shall be taken to fulfil all conditionsrequired concerning current carrying capacity, mechanical strength, glow dischargecharacteristics, corrosion resistivity and easy mounting, etc.

All accessories shall comply with the requirements of IEC 61284, other relent IEC Standards andthe VDE Standard 0210 and 0212 (with the corresponding DIN specifications) where they amplifythe IEC Standards. All accessories shall be tested according to these specifications or to othersimilar and approved specifications.


Tests shall be made in accordance with the applicable standards and the requirements stipulatedunder Sub-Chapter 3.12 .

14.10.1 Tests on the Switchyard on Site

All electrical equipment and installations shall be tested for correct connections of thehigh-voltage circuits as well as of the control and measuring circuits, installation, insulation, andearthing.

All electrical equipment and installations shall be subjected to a complete operational test tocheck the correct operation thereof in terms of the operational requirements specified in theseSpecifications.




Refer to Chapter 26



Volume II – Section VI: Employer’s Requirements: Contract 16 - 132/33kV & 33/11kV Substations

Chapter 15: Low Voltage A.C. and D.C. Auxiliary Power Supplies

Page 1 Kenya Power and Lighting Company Limited Lot 4-Transmission Line Bidding Documents – April 2011

Contents

15 LOW VOLTAGE 400/220 V AC AND DC AUXILIARYSUPPLIES ........................................................................................... 1

15.1 General .......................................................................................................... 1




15.5 General Specification ................................................................................... 1

15.6 415/240 AC Supply ....................................................................................... 2

15.6.1 General ............................................................................................................. 2

15.6.2

Ratings and Design Criteria ............................................................................ 2

15.6.3 Switchboards and Panels ......... ......... .......... ......... ......... .......... ......... ......... ..... 3

15.6.4 Circuit Breakers .......... ......... ......... .......... ......... ......... ......... .......... ......... ......... .. 4

15.6.5 Current Transformers.......... ......... .......... ......... ......... .......... ......... ......... ......... .. 4

15.6.6 Instruments and Relays ......... .......... ......... ......... ......... .......... ......... ......... ........ 4

15.7 Lighting System ........................................................................................... 5

15.7.1 General ............................................................................................................. 5

15.7.2 Switchyard Lighting ........................................................................................ 5

15.7.3

Lighting fixture ................................................................................................ 5

15.7.4 Lamps ............................................................................................................... 5

15.7.5 Ballasts ............................................................................................................ 5

15.7.6 Cables .............................................................................................................. 5

15.7.7 Lighting Control ............................................................................................... 5

15.7.8 Lighting Level .................................................................................................. 6

15.7.9 Indoor Lighting ................................................................................................ 6

15.7.10 Emergency Lighting ......... ......... .......... ......... ......... ......... ......... .......... ......... ..... 7

15.7.11 Hand Lamps and Portable Hand sets .......... ......... ......... ......... .......... ......... ..... 7 15.7.12 Tests ................................................................................................................. 7

15.8 Clock ............................................................................................................. 7

15.9 DC Supply ..................................................................................................... 7

15.9.1 General ............................................................................................................. 7

15.9.2 Batteries ........................................................................................................... 8

15.9.3 Chargers ........................................................................................................ 10

15.9.4 DC Switchboards and Panels ......... .......... ......... ......... ......... .......... ......... ...... 13

15.9.5 Circuit Breakers .......... ......... ......... .......... ......... ......... ......... .......... ......... ......... 14 15.9.6 Instruments and Relays ................................................................................ 14

15.9.7 Battery Conductors and Fuses ......... ......... .......... ......... ......... ......... ......... ..... 15






15.10 Power and Protective Sockets .................................................................. 15

15.10.1 General ........................................................................................................... 15

15.10.2 Power Socket Box ......................................................................................... 15

15.10.3 Domestic Power Outlets (Sockets) ......... ......... .......... ......... ......... .......... ....... 15

15.11 Testing and Commissioning ..................................................................... 16

15.12 Compliance with Specification .................................................................. 16

15.13 Technical Data Sheet ............. ............. ............ .............. ............ ............. ..... 16






15 LOW VOLTAGE 400/220 V AC AND DC AUXILIARY SUPPLIES

15.1 General

This chapter covers the requirements for the design, manufacture, supply, erection, testing andcommissioning of the AC and DC auxiliary power supply system, including switchyard lighting. Allequipment under this chapter shall be manufactured and tested in accordance with the latestrevision of the relevant IEC or other acceptable International standards. The Contractor shalldesign the complete AC and DC system according to the basic requirements mentioned hereinand shall submit his design calculations to justify the ratings and characteristics of the offeredequipment. The Contractor shall deliver under this contract all materials and equipmentnecessary for the proper functioning of the AC and DC auxiliary power supply system.





It is jointly the Contractors and manufacturer’s responsibility to be familiar with any other climaticand physical conditions pertaining to the specific sites as defined in Chapters 1-3 and to allowfor all conditions in designs.

Particular attention should be paid in the design of all equipment to ensure that there is no

damage to working parts or insulation through the ingress of dust, insects, vermin which areprevalent for long periods in the year. All orifices and air vents should be covered by easilyreplaceable weather resisting, fine mesh wire where practicable.


All equipment shall be designed, constructed and tested in accordance with requirements of thelatest version of the standards specified except to the extent explicitly modified in thisspecification.


15.5 General Specification


All components, all equipment as well as the total plant shall be suitable for operation outdoorsspecifically under these conditions and in general under sub-tropical conditions at altitudes of upto 2200m above sea level, to the conditions stated in Sub-chapters 15.2 and 15.3 and shallhave the characteristics as given in Chapter 26 Technical Data Sheets .



The features and constructional details of the equipment shall be in accordance withrequirements stipulated hereunder.






15.6 415/240 AC Supply

15.6.1 General

The Station service is to be supplied from the auxiliary (station) transformers connected to the

33kV or 11kV busbars through fused links. Where only one transformer is installed the othersupply shall come from the distribution system from backup feeder.

At least two auxiliary (station) transformers shall be required to provide auxiliary supplies at thesubstation. The minimum size of the auxiliary transformers shall be 100kVA. A 4-core steel-wirearmoured cable of suitable rating to carry the full load of the transformer shall be provided.

The transformers will not normally be paralleled as only one station transformer shall beconnected to the main low voltage switchboard bus at any time. However, the transformers shallbe suitable for parallel operation.

The main feeds from the station transformers shall be connected to an automatic changeoverbox which will automatically change over to an alternative auxiliary (station) transformer (or otheralternative supply) in the event that the main voltage is lost. The main AC Distribution board willbe fed from the changeover box.

The technical characteristics of the 0.4kV indoor switchgear are described below. Additionaltechnical data are given in Chapter 26 .

15.6.2 Ratings and Design Criteria

The system is to be a 50 Hz, 415 V, 3-phase, 4-wire system with grounded neutrals (TN-S). Forsingle phase wall plug circuits and lighting purposes and all other small power, 240 V AC shall beused.

The ratings and design criteria for any component, any equipment as well as the total plant shallbe:

i) Service voltage 415 V

ii) Power frequency test voltage 1 minute (when nototherwise specified) 2.5 kV

iii) Current carrying capacity of main transformer circuitbreaker not less than 150 A

iv) Short circuit capacities of the main Switchboards shallnot be less than:

Short circuit current, symmetrical r.m.s. value 31.5 kA

Dynamic current, peak 80 kA

Thermal current, 1 second 31.5 kA

The temperature rise of the conductors above ambient air shall not exceed 40 oC at rated current150 A in the three phases. The complete installation shall be designed for continuous operationat 40°C ambient temperature.

The short circuit capacities of the main distribution boards, sub-distribution boards and panelsshall be based on the above mentioned 31.5 kA short circuit current of the main switchboard, but

may be adapted, subject to approval by the Employer/Project Manager, to the reduction of theshort circuit currents caused by intermediate cables and /or by current limiting circuit breakers.

Continuous current rating of the phases and neutral from the transformer and of the busbars inthe main switchboard shall be at least 150 A. The current rating of the feeders shall be ample for






the actual load and have at least 50% reserve capacity compared to the actual load. The figuresgiven in these specifications and on the single line diagrams are indicative only. Only a limitednumber of different makes, types and ratings shall be used, for the purpose of standardisationand interchangeability.

15.6.3 Switchboards and Panels

The switchboards and panels shall be designed, constructed and tested in accordance with IEC60439: Low-voltage Switchgear and Control gear Assemblies.

The boards and panels shall be self-ventilated. No ventilating fans shall be used.

Permissible temperature rise shall not be exceeded even when the free space available for futurefeeders is mounted with feeder equipment and loaded with rated current.

The covers (outside covers and doors, including hinges and locks) shall safely withstand theoverpressure caused by short circuit currents and shall protect personnel against injury.

The main switchboards and the larger ones of the sub-distributions shall be of the floor mountedprefabricated metal enclosed type, with separate compartments for each feeder, etc. Smallsub-distributions may be of the wall mounted steel sheet or cast metal type.

All boards and panels shall be designed for easy access to the equipment, cable terminals, etc.during erection, maintenance, disassembly and extensions.

In addition to the required number of outgoing circuits, The Contractor shall ensure that aminimum of 5% of fully equipped ready for connection of future circuits and 20% of not-equippedreserve capacity is available in the switchgear installation.

The main switchboard shall be designed so that additional panels can be added in the future (i.e.possibilities for extending the busbars).

Operating handles, operating switches and push buttons, signalling lamps, position indicators,instruments, etc., shall be placed on the fronts. Relays that are not incorporated on the circuitbreakers shall be placed in separated compartments, metal shielded from the current carryingparts.The busbars shall be of copper and shall have three phases and neutral. A grounding bar ofcopper shall also be provided and a grounding conductor connection shall be brought to eachfeeder compartment, where the feeder-grounding conductor can be connected to it.

The switchgear cabinets shall be metal-enclosed and partitioned and generally have the followingcomponents:

single busbar system with the necessary current transformers;

busbar earthing pins, including earthing fittings;

a heating/cooling system for each cabinet, controlled by the relative air humidity, with the

possibility of bypassing the control device by a switch except that the heater shall not berequired if the board is installed in an air-conditioned control building;

circuit breaker unit for in-feed with adequate discrimination against the circuit breaker atthe changeover box;

the necessary outgoing units with fuses, contactors, MCBs, instrument transformers,measuring instruments, etc.;

in the partitioned cable connection part, the necessary cable connection fittings shall beprotected against accidental contact, including the necessary attachment components forthe cable end fittings;

one 230 V/10A single-phase three-pin convenience outlet;

ventilation slots;

voltage measuring on in-feed.






Current transformers with cast-resin insulation shall be used. The current transformers mustwithstand dynamic and thermal short circuit stresses. Intermediate transformers shall be avoided.

Only square shape measuring instruments shall be used. The incoming feeder fitted with circuitbreaker shall be equipped with a triple moving iron ammeter and with a single volt meter withfour-way change-over switch for measuring between phases and phase to neutral.

15.6.4 Circuit BreakersIn general, circuit breakers shall be used for all feeders and distribution circuits.

Miniature circuit breakers, MCB's, may be used on small circuits.

Fuses may be used in exceptional cases such as on very light loaded circuits, or in combinationwith small contactors and where the use of fuses is justified for the purpose of selectivity.

In the design of the distribution systems and in the selection of circuit breakers, MCB's, fuses andprotection relays due attention shall be paid to the selectivity of breaker tripping at overloads andat short circuits.

Full selectivity shall be achieved, only the feeder or circuit that has an overload or short circuitshall trip.

Undelayed MCB's shall be used only as the last breaker of a circuit. Selectivity between MCB'sand fuses shall be proved, with ample margin.

The circuit breakers shall be manually operated, except for the breakers in the feeders from theauxiliary transformers and automatic changeover box that shall be electrically operated.

All circuit breakers and MCB's shall have three-phase overload and short circuit protection to beprovided as a part of the breaker assembly or provided separately as for the transformer circuitbreaker (in this case separate current transformers shall be included). The ratings of theoverload and the short circuit protections shall be selected according to the current rating of thecable or circuit to be protected, and in accordance with the requirements of the selectivity asstated above.

15.6.5 Current Transformers

The current transformers shall have synthetic resin insulation or equivalent dry insulation.

The cores for measuring purposes of current transformers shall have accuracy class 1 andinstrument security factor less than or equal to 5. The cores for protection shall have accuracyclass 5P and accuracy limit factor greater than or equal to 10.

Power frequency test voltages, 1 minute:

Primaries 3 kV

Secondaries 2 kV

15.6.6 Instruments and Relays

The instruments shall be 96 x 96 mm square pattern with (at least) 90 o pointer deflection.

Instruments shall be of the three-element type, for unbalanced three-phase load and loadedneutral conductor.

The relays shall preferably be of the solid-state type.

The instruments and relays shall, as far as applicable, be of the same make and type as those ofthe other parts of the plant.






15.7 Lighting System

15.7.1 General

All lighting fittings and all equipment comprising the lighting sub-distribution units must fully meetthe operating requirements at an ambient temperature of 40 °C and at a relative humidity of up to99%. The lighting fittings shall be designed for an operating voltage of 240 V. For protection

against contact with live components, all lighting fixtures must have the following protectionequipment:

protective conductor against connection, or

protective installation,

and must visibly carry the accepted symbol to indicate this.

In substation areas subject to danger of explosion (i.e. battery rooms), the necessary explosion-proof lighting fittings, cable connection boxes and push buttons should be used, in accordancewith IEC 60079. In such rooms or areas, no sub-distribution units shall be installed.

The technical characteristics for the lighting and power installation are described below.

Additional technical data is given Chapter 26. 15.7.2 Switchyard Lighting

The switchyard lighting shall be by means of floodlights with 400 W for bay lighting and 70 W forperimeter lighting.

The switch bay and transformer illumination level shall be 50 Lux at 0.85m height in theswitchyard and for the transformers. The perimeter illumination level shall be 5 Lux. Theperimeter lighting shall be controlled by photocells. All necessary supports, fixing material andcabling from the distribution board shall be included.

15.7.3 Lighting fixture

Lighting fixture shall be of outdoor, flood type, and symmetrical beam spread of not less than2x30 degrees, with built-in ballast. The housing shall be high-pressure die-cast aluminium with anon-corrosive finish; the reflector shall be high-grade aluminium or etched vandal-resistantpolycarbonate. A cat aluminium door frame shall be designed for easy re-lamping. The front glassshall be heat shock-resistant, with a gasket for jet and dust-proof sealing. The enclosureprotection shall be min. IP65.

15.7.4 Lamps

The lamps shall be non colour-corrected, high pressure mercury vapour, 400 W, 240 V and shallhave minimum luminous flux of 20,000 Lm with 16,000 hours service life.

15.7.5 BallastsBallasts shall be suitable for use with 400 W lamps, 240 V, 50 Hz, and shall have at least 90%power factor, sound level not higher than 45 dB. Ballasts shall be designed to ensure very lowoperating temperatures and low losses.

15.7.6 Cables

Wiring cables shall be single core, direct burial. They shall be laid underground or in a cabletrench. Those cables rising along the steel structures should be run in conduits adequatelysecured using bend-it strap.

15.7.7 Lighting Control

Control panels shall be installed inside the control room except that outdoor type junction boxesshall be provided for making connection to the lighting components. The indoor control panelsshall comply with the specifications given in Chapter 2: General Specifications while the outdoortype junction boxes shall be galvanised as specified.






The over current protective devices shall be moulded case circuit breaker. The ON/OFFoperation of the switchyard lighting shall be manual for the switch bay lighting and photocell-controlled for the perimeter fence lighting. The photocell shall be provided with a bypass facility.

The arrangement of lighting branch circuits shall be reliable and easy to maintain.

15.7.8 Lighting Level

Switchyard lighting level shall be designed in such a way that it shall maintain lighting intensity ofat least 50 Lux at 0.85m height on the working areas such as around the transformer and at aminimum of 20 Lux at all other sections.

15.7.9 Indoor Lighting

In general, lighting fixtures wired for three-phase supply and fitted with compensated fluorescenttubes shall be provided for the control building. It should be possible to use them for single orstrip lighting.

Room lights shall generally be controlled by wall mounted light switches of industrial grade.These switches must be located at the access doors of the appropriate rooms.

The internal lighting must achieve lighting intensities as given in the following table. An agingfactor of 20% must be taken into account. Therefore, the lighting intensities of the fittings whennew (new value) must be achieved as a minimum during the acceptance tests.

Location/Room Type of Lighting Fixture*Lighting Utility in Lux

(new / aging)

Control room 3 600/500

switchgear room 2 300/250

AC/DC room 2 300/250

Battery room 2 240/200

Toilets 2 120/100

Store 1, 2 or 4 120/100

Corridors, passage ways 3 120/100*1. free-beaming fluorescent lighting fitting, protection IP 322. water-tight fluorescent lighting fitting, protection IP 543. fluorescent lighting fitting, protection IP 32, with cover4. lighting fitting with halogen lamp, protection IP 54

Fluorescent lighting fittings should be equipped with fluorescent lamps of 1x58 W or 2x58 W.Halogen lighting fittings should be equipped with halogen lamps of 1x250 W or 1x400 W.

The colour of the light must be selected according to the requirements. If different lamps (e.g.halogen and fluorescent lamps) are used in the same room, the used lamps should produce thesame light colour.

Internal lights must be connected in three-phase circuits so that only every third lamp fails when asingle phase fails. Lighting cables for fluorescent lamps should have a cross section of at least2.5 mm².

All luminaries shall be supplied, installed and tested by the electrical subcontractor.

All metal work on the luminaries shall be connected to an insulated earth protective conductor.

Lighting control switches shall be flush pattern with white finished plates.

Grid switches shall have 5 or 10 amp rating; generally where fluorescent discharge luminaries

are controlled switches shall have 10 amp rating, whereas with low energy PL lamp, 5 ampswitches shall be installed.






15.7.10 Emergency Lighting

The emergency lighting shall be operated from the 110 V DC station battery systems. In theevent of a blackout, the emergency system shall be automatically switched on. A manualchangeover facility shall also be provided. The emergency lighting shall be designed simply, asemergency escape route lighting. At least one emergency light must be visible from every point inthe room. Lighting density must be at least 50 Lux.

The Costumer shall ensure that the plants as a whole will function properly under the conditionswhich will occur due to outfall of the substation transformer refer Chapter 2, which requiresminimum 10 hour service time for batteries.

Emergency lighting is provided for in Chapter 4-Civil Works.

15.7.11 Hand Lamps and Portable Hand sets

The hand lamps shall be for additional AC lighting during maintenance works, etc. They shall; beinsulating material. The lens shall be screened against mechanical damage.

The portable battery handsets are for additional DC lighting during maintenance works, etc., inthe case of AC failure. A locker, with the provisions of housing two handsets, shall be placed in

the entrance of the substation. AC socket outlets shall be fitted in the locker for continuouscharging of the batteries. The charging control shall be automatic and a pilot lamp shall indicatethat charging is on. The handsets shall be provided with on/off switch.

The handset shall give flow of approximately 200 lumen, and the battery shall have the capacityof running the lamp for two hours. A type with a short fluorescent tube is preferred.

15.7.12 Tests

The tests shall be made in accordance with the applicable International Standards.

15.8 Clock A clock shall be installed in the control room. It shall be of an analogue type, having continuouslymoving hands. For temperature variations between – 1 and +40 0C with ambient relative humidityof up to 80%, the clock shall be better that +/- 2 seconds deviation in 30 days.

15.9 DC Supply

15.9.1 General

This Section covers the technical requirements of the batteries and battery chargers, the mainDC switchboards and the sub-distribution boards and panel for the dc auxiliary supply of theplants.

110V DC shall be used for the main circuits of the control and protection and for the DC motors,as specified in Sub-chapter 3.29.

48 V DC shall be used as supply voltage for the communication equipment and SCADA facilities.

Single line diagrams for the batteries and chargers and main DC boards are included in thedrawings.

In HV Substation, the 110V DC shall comprise of two independent systems i.e. double batteriesand chargers following one system to carry all loads while the other system is out of services orwhen boost charging one battery.

Under normal operational conditions the two systems shall each carry 50% of their load. Trip 1circuits and trip 2 circuits shall be connected to separate systems.

All boards and panels shall be supplied with the necessary internal wiring. Battery connectionsand cabling in the battery rooms shall also be included.






Tripping all circuit breakers, sounding of alarms and indicating all signals in the substationsimultaneously at the end of the discharge period,

The normal standing load for the full discharge period,

The emergency lights for a period of half an hour during the discharge period.

Alarms shall be provided for the battery faults. These alarms shall generally be available at the

Control Centres.Each cell shall have an individual container of clear plastic (so that the acid level, the plates andthe bottom of the container are clearly visible).The container shall be completely closed and beprovided with an acid spray preventing vent plug. Each group of four containers shall stand in aplastic basin with sufficient volume for collecting all acid from one of the four cells in case of aleakage. The polarity of the cells, and of the complete battery, shall be engraved and easilylegible.

Each battery assembly shall; be complete with wood bases, covered by a double coat of varnishresistant to sulphuric acid.

Bolted insulated interconnections between the cells shall be included.

The battery shall be suitable for more than 1,200 cycles. The Contractor is responsible forcalculating a battery rating which is adequate for all the above duties. Rating calculations shall besubmitted to the Employer/Engineer for approval.

The Contractor shall also determine the number of cells, depending on their nominal voltage,their discharge rate, their final voltage and voltage tolerance. The number of cells shall beselected so that the battery does not exceed 110% of the rated voltage during the float charging.

The Contractor shall deliver authenticated test data proving that batteries of the proposed designand rating have successfully met all test requirements and have satisfactorily been in service forat least 10 years. The end of service life shall be the time when the battery will no longer deliver80% of its rated capacity. Batteries shall have a guaranteed life expectancy of 20 years.

15.9.2.2 Desig n

The battery shall be of compact design with a low weight-to-capacity ratio. Its construction shallensure minimum self-discharge and low internal resistance during the complete lifetime.

Adequate measures shall be taken to prevent internal short circuits and for protection of theelements against mechanical damage.

Positive electrodes shall be of tubular-plate type and shall be made of lead calcium alloy. Thenegative electrodes shall be pasted flat-plate type, made of lead calcium alloy. Posts and internalcell connectors shall be of adequate size to safely handle the rated one-minute current of thebattery. Internal cell connectors shall be lead plated copper, covered with plastic insulatingsheath. Cell containers shall be moulded in strong, impact- and temperature-resistant,transparent plastic boxes with high insulating strength.

Positive cell terminals shall be plainly and durably marked "POS+", negative cell terminals "NEG-". Terminal and cell connectors shall be of corrosion-resistant material. Furthermore, each cellshall be permanently marked with at least the following information:

cell number,

year and month of production,

manufacturer, battery type, rated voltage and capacity,

Serial number.

15.9.2.3 Battery Acc esso ries

Batteries shall be supplied complete with cell connectors, bolts, cable sockets, cell and standinsulators and identification discs. Assembly wrenches, harnesses for lifting and all special toolsrequired for installation and maintenance shall be supplied, too. All required equipment to fill the






cells with electrolyte on the site shall be supplied (if applicable). The accessories shall include,but should not be limited, to the following items:

installation and maintenance instruction in English and the national language,

hydrometer and thermometer (if applicable),

DC volt meter,

hand-operated siphon tube with suction bulb and funnel for emptying any cell into acontainer (if applicable),

anti-corrosive grease,

Safety equipment (eye washer, goggles, gloves, apron, etc.).

These accessories shall be housed in a stable box which is suitable for wall mounting.

15.9.2.4 Rack s

Battery cells shall be arranged on appropriate racks. These racks shall be prefabricated, welded,acid-resistant, plastic-coated steel constructions for assembly on site, and shall be equipped with

devices for fixing on the floor and/or wall. The racks shall be designed according to thedimensions and weights of the battery cells, according to the available space and climaticconditions on site. Racks should be suitable for withstanding earthquakes of M8 class. Thebattery cells shall be arranged in tiers, so that each cell will be readily accessible for maintenanceand inspection.

15.9.2.5 Deliv ery

The battery cells shall be fully pre-charged by the Manufacturer prior to shipment. The packingshall be shockproof and suitable for shipment over rough country roads. The exact method ofdelivery shall be specified in the Bid.

15.9.3 Chargers

15.9.3.1 General

Two full-capacity battery chargers shall be delivered for the redundant supply of 110 V. Theyshall be of static rectifier, fully automatic and solid state type, regulated 415 V, 50 Hz, threephase/four wire input voltage. They shall be without fan or moving parts. The rated current of thebattery chargers shall be selected to allow for recharging a fully discharged battery in 5 hours, inaddition to simultaneously supplying the DC load.

The rectifier shall be of full wave bridge type, using silicon thyristors. AC and DC circuit breakersof adequate capacities shall be provided to protect the charger against overload and shortcircuits.

The charger shall be connected to the 110 V battery system and shall be powered through thebus of the 415 V AC station auxiliary supply. It shall be designed for the ratings andcharacteristics specified in the technical data sheet mentioned above. In addition, it shall complywith the following technical data and requirements:

Power Supply 15V AC three-phase or 240V AC single-phase.

Output voltage adjustable between 110V = 15% resp. (for protection and control etc.)

Stability of the output voltage Less than +/- 1% for the maximum input voltageand frequency variations, and from 1% to 95% ofrated output current.

Maximum deviation of currentlimitation +/- 2% of rated current

Ripple of output voltage






o without the batteryconnected

Less than 4% peak-peak of the rated outputvoltage

o with battery connected less than 1% peak-peak of the rated output voltage

Dry type transformers and solid state (thyristor or transistor) rectifiers shall be used throughout.Each charger shall be supplied with reactor to reduce ripples.

The chargers shall be completely equipped for fully automatic and controlled charging and floatcharging of the batteries, and shall be of a constant voltage type with current limiting device.

Each of the chargers for the 110V batteries shall be rated to maintain normal charging and floatcharging of both batteries.

The Contractor shall be responsible for calculating the required DC output current, consideringthe DC load required to maintain the battery fully charged. The offered chargers shall beadequately rated for all required duties.

The technical characteristics of the charger are described below. Additional technical data aregiven in Chapter 26.

15.9.3.2 Tech nic al Characteris ticsIn normal operation, the chargers shall maintain the battery normally floating so that no dischargeoccurs and the battery remains fully charged. Operation of the chargers shall follow the I/Ucharacteristics according to the latest IEC recommendations.

The charger voltage shall be regulated so that it shall maintain the float charge automatically,irrespective of the variations in voltage/frequency of the AC supply and the DC load within thespecified limits.

The voltage/current characteristics of boost charge shall have tapering characteristics in order tominimize gasification. Maximum boost charge current shall be marked on the provided ammeter.

The chargers shall be capable of charging a totally discharged battery to at least 80% of fullcharge level in a maximum of 5 hours while supplying connected loads. During boost charging ofthe battery, maximum voltage supplied to the loads shall be limited. The design shall also containprovisions for initial charging of the battery.

The charger shall be protected against overloads and shall limit the output typically to 125% of itsmaximum rating on short circuits of the DC output. A current limit circuit shall protect a dischargebattery from overcharging when connected to the charger.

Fast-acting fuses shall be incorporated in the charger to protect the thyristor bridges againstdamage due to capacitor failure in the output circuit.

Efficiency of the charger shall not be less than 80%. The Contractor shall specify the charger effi-ciency and input power factor at both full and lightly loaded conditions.

a) Float Charging

The output voltage regulator shall be adjustable within limits and shall be designed insuch a way that no special tools are required for such adjustment. The voltagereference point for control of the charger output voltage shall not be obtained from acharger-external source.

The output for the charger on float charge shall be equal to the normal batterystanding load plus the recommended finishing charge rate. The charger shall haveelectronic protection to avoid discharging the battery through the charger, should thelatter become defective.

b) Boost Charging

Under boost charging conditions, the charger shall fully recharge the battery after aheavy discharge without gassing or damage to the battery. A timer relay graduatedfrom 0 to 48 hours shall be incorporated in the design for selecting and setting of






boost charge rates. Boost voltage and boost timer settings shall be chosen to ensurethat a discharged battery can be fully charged within the period specified above.

It is not permissible to disconnect the load from the supply during boost charging.Thus, it may become necessary to use such devices as voltage dropping diodeswhich are switched in and out by means of a voltage sensing relay and contactor inorder to ensure that the load voltage does not rise above the upper limit.

Manual boost charging shall be required in the following instances:

i) during the initial charging of the battery, prior to its operation,

ii) during maintenance of the charger or

iii) After a prolonged mains AC shutdown or outage,

iv) Prior to battery capacity tests.

15.9.3.3 Cons tru ctio n

The charger cabinet shall be a metal-clad cubicle with front door, floor mounted, indoor type. Allequipment shall be accessible from the front side. The cabinet shall be adequately ventilated andshall be completely vermin-proof. The degree of protection shall be in accordance with IEC60529.

Each charger shall be complete with instruments, breakers and protection, including but notlimited to:

Breakers and protection on AC and DC side, with alarm contacts.

One lamp indicating that the charger is charging.

Alarms as specified below

The following equipment shall be mounted at the front of the charger cabinet; each componentshall be labelled for identification:

An ON/OFF main switch with green lamp/LED for ON position,

A four-position output selector switch for the following settings:

o OFF,

o FLOAT,

o BOOST,

o AUTOMATIC,

A red lamp/LED to indicate boost operation,

The following flush-mounted meters with appropriate scales:

o One DC volt meter

o One DC ampere meter

o One AC volt meter with phase selector switch.

o One AC Ammeter (the phase on which it is connected shall be indicated).

The following fault conditions shall be indicated and shall activate a signal/alarm to the controlsystem; the alarms shall also be transferred to the Control Centres:

Charger failure,

Undervoltage,

Overvoltage,

Loss of DC supply,






Earth fault.

By means of an automatic change over switch the charger shall change from normal chargingand float charging to boost charging of the battery.

All non current-carrying metallic parts of the cabinet shall be suitably and effectively connected tothe grounding system. A hinged door with locking shall be provided for accessing the equipmentfrom the front side of the charger. The door shall be connected to the enclosure by means ofseparate flexible grounding straps.

A name plate of corrosion-resistant material shall be fixed to the front side of the cabinet. It shallcarry the following information, legibly marked in English and Swahili:

Manufacturer's name or trademark with type designation,

Serial number,

Rated direct current,

Rated DC voltage of the charger,

Rated AC supply voltage with number of input phase,

Rated frequency,

Range of adjustments for float voltage, boost voltage, current limited,

Degree of protection.

A circuit diagram of the complete charger equipment shall be fixed at a suitable place inside thecharger cabinet for inspection. All components represented by parts, symbol and subscriptfigures of letters in the circuit diagram shall be identified by the same symbols and subscriptsmarked at or close to the locations where they are installed.

In addition, all test points to be used for trouble shooting shall be suitably identified.

15.9.4 DC Switchboards and Panels

These panels will be required for power and lighting distribution circuits. The Contractor shalldetermine the actual number of outgoing circuits according to the requirements of the design.The panels shall be designed to ensure safety during operation, inspection and maintenance.

The provisions of Sub-chapter 3.25 and 15.6.3, shall apply for the DC boards. Reference shall bemade to these provisions.

The following modifications are applicable:

a) Circuit breakers on the main DC switchboards, which are rated 50A and higher shallbe withdrawable.

b) The DC busbars shall have two poles. The bars and the connection conductors to thebreakers shall be insulated.

The 110 V distribution panel shall be of sheet steel, floor mounted type. The cabinet shall beadequately ventilated and shall be completely vermin-proof. The degree of protection shall be inaccordance with IEC 60529.

All non-current-carrying metallic parts of the cabinet shall be suitably and effectively connected tothe grounding system. A hinged door with locking shall be provided for access to the componentsfrom the front of the charger. The door shall be connected to the enclosure by means of separateflexible grounding straps.

All busbars shall be copper, rated and braced to withstand available short circuit currents to thepanel board, but in no case rated less than 18 kA for 1 second. Separate chambers shall be

provided for busbars, feeders and cable connections.The outgoing feeders shall be equipped with cable connection facilities, appropriate for the cross-sections of the cables used for the particular purpose.






Circuit breakers shall be of moulded case, manually operated type, with quick make quick break,trip-free operating mechanism and an automatic thermal/magnetic trip device.

The number and rating of circuits shall be adequate to meet the Contractor's design. This shallbe supported by design calculations subject to approval of the Employer/Engineer.

Circuit breakers shall be designed for panel board mounting and shall be provided with suitableclamp-type connectors.

Double-pole breakers shall have a single operating handle which shall operate all polessimultaneously to close or trip the breaker. The operating handles shall clearly indicate whetherthe breakers are in "on", "off" or "tripped" position.

Fuses shall be provided for all fusible devices. They shall be of current-limiting, high-interruptingcapacity type.

The following flush-mounted meters with appropriate scales shall be provided:

1 DC volt meter,

1 DC ampere meter.

A name plate made from corrosion-resistant material shall be fixed on the front side of thecabinet. It shall carry the following information in English and the national language:

Manufacturer's name or trade mark with type designation,

serial number,

rated service voltage,

rated current,

short circuit rating,

degree of protection

15.9.5 Circuit BreakersThe provisions of Sub-chapter 15.6.4 shall apply also for the DC breakers. Reference should bemade to these provisions.

The following modifications and additions are applicable.

a) All circuit breakers shall be manually operated.

b) The breakers shall be two-pole, and with thermal overload and magnetic short circuitprotection in both poles.

c) All circuit breakers, miniature circuit breakers, switches, contactors, fuses, etc. shallbe of a type specially designed for the use on DC, and on dynamic current and the

making and breaking shall be ample for the short-circuit power of the batteries.d) Due attention shall be paid to the selectivity of breaker tripping.

e) All circuit breakers, miniature circuit breakers, switches and contactors shall have analarm contact.

f) On circuits protected by fuses an under voltage relay with alarm contact shall beprovided.

15.9.6 Instruments and Relays

The provisions of Sub-chapter 15.6.6 shall apply wherever applicable. Reference should bemade to these provisions.

In addition each main DC switchboard shall be provided with a voltage-monitoring device withalarm contacts and signal lamps, one lamp for each type of fault. The device shall monitormaximum and minimum voltages as well as ground faults on both poles.






15.9.7 Battery Conductors and Fuses

Conductors from the batteries to the fuse boxes shall be mounted with short circuit and earthfault proof. That is, the conductors shall be single pole insulated and in addition placed oninsulators, separate for each pole. All conductors shall be placed at minimum 5 cm distance fromeach other, even at crossings.

The conductors shall lead through insulating pipes in the wall of the battery room to closed fuseboxes made of insulating material on the wall outside the battery room. For the 110V DC systemthere shall be one box for each pole. The water hole shall be tightened against gas intrusion.

Conductor insulation, insulators and pipes shall be resistant to sulphuric acid.

15.10 Power and Protective Sockets

15.10.1 General

The power and protective sockets are intended for the plug-in connection of mobile electricalequipment for repair and maintenance of any kind. The mobile electrical equipment must be fitted

with the necessary three-phase and earthing contact plugs.

15.10.2 Power Socket Box

The power supply to the power socket box shall be provided from the sub-distribution board. Ineach substation, at least one power socket shall be installed. Plugs and sockets must be inaccordance with CEE form. Power sockets shall have stainless steel metal casings, resistant toimpact such as direct sun, etc. They shall be suitable for wall mounting. The sockets shall be ofoutdoor type even if installed indoors, and shall operate satisfactorily under direct sunlight. Eachsocket shall be equipped as follows as a minimum requirement:

with the necessary wire inlets at the top of the power socket casing for the incoming andoutgoing feeders, including necessary glands or blanking plugs,

with the necessary fuses in the top of the metal casing,

with the necessary main manual switch, before the fuses of the socket circuits, placed inthe top of the metal casing,

with one three-phase socket, 400 V, 32 A, 5-pole (three-phases, neutral and earth) inCEE form, in the bottom of the metal casing

with two AC single-phase sockets, 230 V, 16 A each, screwed, 3.pole (phase, neutral andearth) in CEE form, in the bottom of the metal casing,

with all necessary fuse bases, connections and its intermediate terminals and any otherattachment fittings.

All sockets shall be provided with plugs. The power supply of the sockets shall be provided withthe PVC power cables. For the internal wiring in the metal casing, stranded copper conductorswith PVC insulation shall be used.

15.10.3 Domestic Power Outlets (Sockets)

In rooms such as switchgear, battery and control rooms, offices, etc., an adequate number ofsurface-mounted domestic power outlets (sockets) shall be provided. In corridors, one poweroutlet must be available very 10 meters. Power supply shall be provided from the lightingdistribution boards. Power outlets must be 13 A, three-pole type, i.e. phase, neutral and earth. Allsockets must be in accordance with CEE form. Generally, plastic-insulated power outlets for 230V AC shall be provided.

The power outlets (sockets) shall be supplied via the single-pole MCBs of the lighting distributionunits via three-core cables. Not more than 5 power outlets (sockets) may be supplied from onecircuit. The conductor cross section of the cables supplying the sockets must be at least 2.5 mm².







Tests shall be in accordance with applicable international standards and provisions of Sub-chapter 3.12.

Special tests on site: Tests to verify the breaker tripping selectivity.




Refer to Chapter 26




16. TECHNICAL SPECIFICATION FOR SCMS



Volume II – Section VI: Employ er’s Requirements: Contract 16 - 132/33kV Substations and Bays

Chapter 16: Substation Control and Monito ring System


Contents

16 SUBSTATION CONTROL and MONITORING SYSTEM .................... 1

16.1 General ............................................................................................................ 1

16.2 Particulars of Electrical System ................................................................... 2

16.3 Particulars of Environment ........................................................................... 2

16.4 Standards , Unit s and Language ................................................................... 2

16.5 Detailed Specification .................................................................................... 3

16.5.1 General ............................................................................................................... 3

16.5.2 Syst em Conf igurat ion ....................................................................................... 3

16.5.3 Cont rol Func tions ............................................................................................. 4

16.5.4 Man-Machine Int erface/Subst ation Computer ................................................ 8 16.5.5 Data Logging ................................................................................................... 10

16.5.6 Software development t ool s and maint enance ............................................ 10

16.5.7 Subs tat ion gatew ay ........................................................................................ 10

16.5.8 Bay Cont rol Unit s ............................................................................................ 11

16.5.9 Unin terrupt ible Power Supply (UPS) ............................................................. 13

16.5.10 Spares .............................................................................................................. 13

16.6 Training ......................................................................................................... 13

16.7 Compliance with Specification ................................................................... 13

16.8 Technical Data Sheet .................................................................................... 14






proper and trouble-free operation from the bay units (installed in the control and protectioncubicles and in the metal-clad cubicles) with position indicators for all circuit breakers,isolating switches, and working earth switches,

all alarms and indicators associated to protection tripping,

all metering and billing instruments,

all items for control, monitoring, remote control, protection and interlocking circuits,

communication links to the National Control Centres and Area Control Centres, etc.,

protection management,

event recording.

The Contractor shall ensure that after handing over, a minimum of 35% spare function capacity(hardware and software) and 20% spare parts for future extensions are available, at least one foreach type of component.

The control, metering and protection equipment shall be placed in separate panels

The panels shall not be unnecessarily crowded with instruments, but shall have space for amoderate extension. The number of panels to be included in the boards shall be decided by theContractor. Accompanying drawings showing in sufficient detail the types of boards and mimicdiagram proposed for each project with all necessary switches, position indicators and instrumentsshall be provided.

The supplied and installed instruments, relays, switches and other equipment shall properly matchthe equipment to which it shall be connected, and which is included in the sections dealing with thedifferent types of switchgear for transformers, transmission lines and other items. Likewise thehardware and software used shall be such that it will be able to interface with instruments withoutthe excessive use of protocol converters.

16.2 Particulars of Electri cal System




It is jointly the Contractors and manufacturer’s responsibility to be familiar with any other climaticand physical conditions pertaining to the specific sites as defined in Chapters 1-3 and to allowfor all conditions in designs.



All equipment shall be designed, constructed and tested in accordance with requirements of thelatest version of the standards specified herein except to the extent explicitly modified in thisspecification








16.5.1 General


All components, all equipment as well as the total plant shall be suitable for operation outdoorsspecifically under these conditions and in general under sub-tropical conditions at altitudes of upto 2200m above sea level, to the conditions stated in Sub-chapters 16.2 and 16.3 and shallhave the characteristics as given in Chapter 26 Techni cal Data Sheets .



The features and constructional details of the equipment shall be in accordance withrequirements stipulated hereunder.

16.5.2 System Configurati on

The basic configurations as outlined in Figures 1 below shall be acceptable. The Contractor shallprovide solutions based on these suggested configurations. The Contractor’s solution shall be tothe Employer/Project Manager’s approval.

The conf iguration has the protection and control panels located in the control room with cablesrunning from the various pieces of equipment in the switchyard to the control room. Theprotection and control functions may be separated in separated panels or they can be integratedinto common panels. The substation control computer will also be located in the control room.

Simplif ied Station Supervisory Control Control RCC/NCC

(PC or Lap Top)Communication Protocol IEC 60870-5-101

Local Robust Communication Ring BusSuporting IEC 60870-5-101 Protocol

Teleprotection Chanel(s)Control and Relay Panel/Instrument Section

Cables fromYard to control Room

LINE 1 BAY LINE 2 BAYTRANSFORMER 1 BAY TRANSFORMER 2 BAY

Bays with Combined Control & Protection Bays with Seperate Control & Protection

Microprocessor Based Control System Archtecture - Alternative 1

LOCALCONTROL

UNIT

PrimaryComponets- Tr ansf orme r s- OL TC- Circ u i t Br e ake r s- D isconnec to r s- Ear th ing Switc hes- Measuring Transformers

LOCALCONTROL

UNIT

PrimaryComponets- Cir cu i t Br e ake r s- D isconnec to r s- Ea rth ing Swi tche s- Measuring Transformers

LOCALCONTROL

UNIT

Primary Componets- Cir cu i t Br e a ke r s- D isconnec to r s- Ear th ing Swi tc he s- Measuring Transformerss

LOCALCONTROL

UNIT

Primary Componets- Tr ansf orme rs- OL TC- Circ u i t Br e ake r s- D isc onnec to r s- Ear th ing Swi tc hes- Measuring Transducers

SUBSTATIONGATEWAY

TELEPROTECTION






In general, all essential alarms, indications, electrical measurements including energy(accumulators) and controls required in the local control room are required remotely at theControl Centres.

The Contractor is fully responsible for the integration of the Substation Control System with theexisting SCADA/EMS systems of the Employer at the Control Centres and a takeover certif icatewill not be issued until the supervisory functions are successfully accomplished.

The Employer will however, do database updating at the Control Centres to accommodate thenew substations, while the contractor shall program his SCMS according to format agreed uponwith the employer.

16.5.3.2 General Functions

The HV substations shall be provided with a microprocessor based substation control andsignalling system. The system shall accommodate control, data acquisition, alarm handling andtrend analysis.

The control of HV and MV circuit breakers, isolating switches and tap changers shall take placein a hierarchy with four levels where from each level one may block access from higher levels:

Local control from the HV individual equipment and MV switchgear metal-clad cubicles,

Remote control level 1: from the cubicles in the Control room or from the bay units, Remote control level 2: from the substation control and monitoring system,

Remote control level 3: from the regional control centre.

All earthing switches shall only be operated locally.

The substation control system shall be designed to provide the following:

Control of circuit breakers, isolators and grounding devices.

Bay-oriented interlocking

Station interlocking

Run time supervision

Process supervision and measuring

Event logging and storing (minimum 3 months storage)

Measurement functions (1Ph and 3PH MW and MVar, Frequency)

Tap-changer control (Raise/Lower commands for LV voltage control)

Interface with Transformer and Tap changer Management systems.

Interface with Protection Relays (IEDs)

Voltage regulation functions.

General Description

This specification calls for a microprocessor based Substation Control and monitoring System(SCS) for HV substations. The supplier is to obtain all necessary licenses and documentationfrom the original protocol manufacturer to allow communication with the National Control Centre.The offered substation control system shall have high usability and availability.

A substation computer must be available for analysis, maintenance, trend logging, control andextensive reporting functions.

The SCS system adopted shall have dual redundant serial communication with the ControlCentre(s) (CCs) through a substation gateway, via fibre based telecommunications system. TheSCS will be configured in a loop with other RTUs at the Control Centre Front Ends.

The Control System shall be able to communicate with the master stations at the Control Centres






(Regional or National). All local data on status indications, measured values, protection signalsand energy shall be transferred to the master station at the Control Centres. It shall be possibleto control all co ntrollable objects remotely from the station computer. All relevant auxiliaryinterposing relays, bi-stable relays and transducers shall be provided.

The SCS shall be prepared for future extensions with new bays where Distributed bay Controlunit communicates with the SCADA/EMS system by an open standard protocol IEC 60870-5-101. All hardware shall be specially designed for application in high voltage plants andreferences for such applications shall be submitted.

16.5.3.3 Specific Functions

16.5.3.3.1 Inherent Safety Features

The SCS is to be designed with a self-monitoring system with diagnosis that can continuouslysupervise vital functions on the main processor and distributed control units. The faults are to bedisplayed centrally on the station computer , locally on the faulty equipment and to the NationalControl Centre through the substation gateway.

The software is to be provided with a possibility of introducing passwords for the most centralfunctions to avoid unintentional operation of the plant by unauthorized personnel.

All commands shall follow a logical sequence and the software shall be designed in such a waythat the user is guided step by step through each sequence by identifying visually the remainingvalid entries (ref. IEC 60870-5-5 section 6.8, "Command Transmission") .

A prerequisite for successful execution of a command shall be that the bay con trol unit hasreceived the telegram selecting the object to be operated , that all interlocking criteria are f ulfilledand that the selection relay for the particular object has operated. The selection and commandcircuits are to be continuously monitored.

In general "fail safe" procedures are to be introduced throughout , meaning that if a failure on thesystem arises, the system shall immediately revert to a safe mode.

No fault in the gateway, the substation computer or the interfaces between the systems shallinterrupt or affect the running of the station. No fault in any one Bay Control Unit or in thecommunication equipment shall interfere with the other Bay Control Units or interrupt orotherwise block the operation and protection of the substation unless it is a fail-safe procedure.The failure on the substation workstation must not affect communications with Control Centres oroperations from the Control Centres in any way.

Backup copying and program maintenance shall be possible without interfering with the actualoperation of the control system.

All control and monitoring functions necessary for a secure and reliable operation of thesubstation shall be provided. The following are the minimum functions required and this list maynot be exhaustive:

Input of binary and analogue values,

Control, interlocking and supervision of the individual bays and the entire substation,

Tap changer control of power transformers including automatic voltage regulator (avr),

Alarm handling in the bay computers and in the station computer,

Analogue value processing,

Indication of bay and substation status,

Indication of measured and processed analogue values,

Accumulator values

Station control via video display system,






Automatic chronological control of standard switching routines,

All hardware, software and telecommunication facilities for future remote control andsupervision of the substations from the SCADA system control centre,

Emergency control of each bay from the related bay units,

Synchro-check function for all breakers,

Display of trend values, Fault indication,

Event recording,

Evaluation and archiving of historical data (loads, faults).

An integrated voltage- and synchro-check function shall also be provided for manual closing ofcircuit breakers. The voltage-check function shall include life-bus/dead-line conditions, dead-bus/live-line conditions and dead-bus/dead-line conditions. It shall be possible to set or selectany combination of these conditions that will allow closing. For live-bus/live-line conditions, thesynchronise check function shall take precedence.

The synchronise check function shall allow circuit breaker closing only if the voltages on both

sides of the breaker fulfil the preset conditions as to magnitude, phase and frequency difference.The voltages shall be considered in synchronism when their phase angles are measured to bewithin the angle, adjustable from 20 to 60 degrees. During synchronising, a closing order shallonly be accepted if the synchronising conditions are fulfilled.

All data and parameters specified to the individual distributed control units shall be stored in anon-volatile memory so no local logic or information will be lost due to power supply failure.

16.5.3.3.2 Response Time

The control system shall satisfy the response time criteria stipulated below.

Time to regenerate the total status information for the station by updating all databaseswith the total signal information from all bay computers:

Maximum 10 seconds

16.5.3.3.3 Interlocking

The Bidder shall explain in detail the interlocking system and the underlying philosophies-Theinterlocking system shall be made as fail safe as possible and if a software logic system in part ofthe interlock ing chain , the software shall be thoroughly tested prior to installation anddocume ntatio n shall be provided that similar systems have been in operation in other plants.

Elements, which require a comprehensive description, pertain to:

Basic functions (computer logic or ordinary relay techniques).

How inter-bay communication is built up.

Power supply. Emergency procedures in case of power supply failure or other equipment failure.

The interlocking conditions shall be checked by the computer. The operator can execute anycommand only if the device is not blocked and no interlocking condition is violated. Aftercommand execution, the operator shall receive a message, either about the new switchingposition or about the refused switching.

16.5.3.3.4 Redundancy

The Bidder shall explain in detail all system redundancy functions included in the SCS offer.Redundancy functions that are not part of the offered configurations, but will increase the






operational reliability and safety shall be of f ered as options.

16.5.3.3.5 Time Synchronizing

Events and alarms shall be time tagged in local bay control units and relay protection units, andshall be transferred to the remote and supervisory control system with this time tag. All timetagged events and alarms should have a reso lution equal to or better than 1ms

The Bidder shall describe how to synchronise bay control units. Accuracy limits with typicalvalues as well as maximum deviations are to be stated in the offer for time difference betweenstation master control unit and the Control Centres and between station master control unit andbay units/protection units.

Synchronising the control units shall be handled using GPS.

16.5.3.3.6 Trend Curves and Limi t Monitoring of Analogue Measurements

It shall be possible to monitor all electrical measurements and transformer taps as trend curves.The Bidder shall describe resolution of real time trend curves, standard resolution on storagetrend curves and storage capacity-

At least two upper and two lower set point limits shall be provided for all analoguemeasurements. Continuous monitoring of these limits shall be possible. The set points shall beadjustable via the VDU display in the control room. Blocking and deblocking of associatedalarms shall be possible.

16.5.3.3.7 Prior iti es

Commands, indications and measurements shall be on the following prioritisation

i) Commands

ii) Indications

iii) Measurements

Irrespective of what is displayed on the VDU the last alarm shall be shown. It shall be possible toretrieve and sort selected parts of the alarm and event listings, and also group alarms on a bay

basis or on the basis of type of alarm, e.g. protection, overload, etc.16.5.3.3.8 Status Indic ations - Protocols/List ings

All events are to be stored sequentially on a mass storage medium in the station master controlunit. In addition they are to be logged sequentially on the printer in the control room. Alarms andfaults are to be given priority in relation to status changes. In the archive in the mass storagemedium status indications and fault indications (from protection relays) are to be loggedseparately in different files. All events are to be transmitted to the Control Centres.

All alarm indications are to be presented on a separate alarm list on the VDU, with normalacknowledgement routines. The list is to be divided into two sections displaying non-fleeting andfleeting faults.

It shall be possible to display only sections or subsections of the overall alarm list. It shall bepossible to acknowledge alarms from the keyboard. Acknowledged alarms shall be marked in thelist. Faults that appear and disappear without being acknowledged shall be specially marked inthe alarm list. The alarm list shall be displayed on the screen, and printouts shall be possible.

Acknowledged and unacknowledged alarms shall be given separate colours.

A signal is to initiate the alarm bell in the control room in case of an alarm, when the stationlocal/remote switch is in local position.

Alarms shall also be available on bay unit level.

16.5.4 Man-Machine Interface/Substati on Computer

The man machine interface between the substation control room and the high voltage system






shall be the workstation . The workstation shall be equipped with VDU, PC, keyboard , mouse, andprinter for complete remote monitoring and control functions from the substation control room.

All remote control for the substation shall be based on graphic displays in the VDU. The displaysshall be organized in a hierarchical manner. The displays shall give the possibilities to control allcircuit breakers, isolators and transformer taps. In addition all breaker positions, electricalmeasurements and transformer taps shall be shown in the displays. All substation events andalarms shall be presented in separate displays.

At minimum the workstation shall include the following displays:

Substation overview with limited number of measurements and control possibilities.

Separate display for each voltage level giving all available information about the bays andgiving possibilities to control circuit breakers, isolators and transformer taps.

Separate display showing status for each bay control unit, master control unit, SCADAinterface and communication network.

Separate display for events and alarms.

Separate display for trend curves.

One display shall be capable of showing a single line with all relevant data (at least 50 switching

devices such as circuit breakers, disconnectors, earthing devices; 20 measuring values, 40additional indications). Such a typical display shall be completed at least within 1 second afterselection by the operator. Layouts of the displays are subject to the approval of the Employer.

Displays for the different voltage levels shall also allow the blocking of the supervisory control.Blocking of supervisory control shall be possible for each bay separately, and also for all bays ateach voltage level. Status supervisory control blocked / not blocked shall be shown in thedisplays.

It should be possible to turn remote and supervisory control on/off using a selector switch in thecontrol panels. Status remote /supervisory control on /off should be shown in display.

Dynamic change of colours in the display shall indicate the status of the grid. Different colours onmimic diagram shall indicate the different voltage levels. Circuit breaker, isolator and earthswitch position shall be indicated using different colours of the breaker symbols. Any trip alarmfor a particular circuit breaker shall also be indicated. Bays with communication errors shall beindicat e d using separate colours on the mimic diagram.

No displays should be unnecessarily crowded w ith information and control features. Ifnecessary, displays should be divided into different layers organised in a hierarchical way withinformation organised in different layers. The Bidder shall describe the offered solution withnumbers of displays and examples of organizing.

The system shall have a possibility of introducing passwords giving different categories of users ' access to the following levels:

Access to status only

Permission to execute commands

Permission to change and program protection relays

Permission to authorize other users

Permission to engineer/modify the system

Any other permission level the Contractor may recommend

Details regarding use of passwords are to be finalized by the Employer/Project Manager. Anyinvalid entry shall be detected by the system and an explanatory message displayed on the VDU.The system shall have help support functions.

In addition to VDU, keyboard , mouse and PC, the man-machine interface shall be provided witha printer that logs all events in the same sequence they are reported from the bay control units,






including an attempted violation of password-oriented permissions.

16.5.5 Data Logging

The Control System shall have event and data logging facilities (hard -disc) for analogue anddigital signals with a capacity of at least 3 months storage. Date and time of all events shall beindicated. The time shall be displayed to a resolution of two decimal digits of the second. It shallbe possible to retrieve data for storage on an external storage medium for future reference andanalysis.Recalling of data from the data logger memory for display on the VDU shall be possible. The datashall be made available either in a tabular form or as selected variables on a trend display.Printed information may be either in a tabular form or in a perforated report form and may beautomatic at specific times or on request.

Comparison of real time data and historical data trends shall be possible on the display withoutaffecting the on-line data logging.

16.5.6 Softw are development too ls and maintenance

Program development editing, compilations and linking shall be available on the workstation andlaptop. This implies that all source files containing source programs must be supplied to enable

future software development and modification. All program development and support functions to be supplied shall be described in detail, so asshall the manner in which personnel would use such facilities to create, debug and integrate anew program into the system.

A detailed description of the interface of the bay control units and protection relays in the SCSshall also be included.

The programming languages supported by the system shall be stated.

Any apparatus that enables testing, configuration and diagnosis of bay control units, gateway andsubstation LAN e.g. laptops, communication devices is to be included in the tender.

16.5.7 Substati on gateway

The Substation Gateway shall include a computer for superior functions and designed forprotection fault processing. This computer shall be equipped with a high-performancemicroprocessor and real time operating system. It shall have access to all subsystems at baylevel, shall collect signals and information, issue commands and perform the signal processingrequired for the connected substation. This computer, together with all necessary input/outputequipment, shall be placed in panels in the control room. It shall be supplied by 110 V DC fromthe station UPS power supply. LEDs on the front of each input/output module of the SubstationGateway shall indicate the status of the respective circuits. Power supply to the SubstationGateway shall be redundant.

The offered Gateway must :

Be configured to operate with a suitable protocol that shall enable it to communicate withthe Employer’s existing Control Platforms.

Emulate one of the RTU types used by the Employer so that it can be controlled in a slveconfiguration.

Operate in a loop configuration towards the Control Centres also being able to relaytelegrams between other substations and the Control Centres.

Communicate with future SCADA/EMS system by an open standard protocol like IEC61850, IEC 60870-5-101.

Communicate with metering, bay control units and protection relays by an open protocolaccording IEC 61850 standard protocols.






Communicate with RTUs at nearby substations as Master and relaying the data to theSCADA/EMS system at the National Control Centres and at the substation workstation.

16.5.8 Bay Contro l Units

16.5.8.1 General

The bay computers shall be based on a microprocessor technology and real time operatingsystem. Power supply for the computers shall come from the station battery and shall beredundant.

All breakers, isolators (including bypass and busbar isolators) and transformer taps as well asalarms from the particular bay are input to the bay control unit.

The bay computers shall perform all bay-internal programmes, command sequences, collectionof signals and information, outputs of commands and signal processing required for the differentswitchgear units of the corresponding bays. All commands from the remote and supervisorycontrol are given to bay control unit, which will execute the commands. External interlocks shouldbe software in the bay control units but the existing mechanical interlocks shall be maintained.

All alarms and events from relay protection equipment should either be transferred to workstation, submaster control unit or control unit using the communication network. Signals from

protection equipment can alternatively be hardwired to the bay control unit.Generally, the following tasks shall be performed:

signal acquisition,

acquisition of measured and counted values,

monitoring of execution of commands,

data pre-processing,

data communication to the station computer and connected subsystems,

calculation of derived operational measured values,

generation of group signals,

Self-monitoring routines.

The bay control units must have synchro-check function for feeders, automatic tap-changer,voltage control for transformer bay and must have a programming function that allows theEmployer’s personnel to design their own programs e.g. load shedding and tap-changer voltagecontrol.

The emergency control shall require a special key. Normal control of the bay from the stationcomputer shall be disabled if the emergency select key is in emergency operation position.

The electronic systems shall be equipped with self-supervision and testing functions. Each circuitboard shall contain circuits for automatic testing of its own function. These circuits shall interactwith a test and diagnostic programme controlled by the central unit.

Faults in a unit shall be indicated by a red LED on the front edge of the unit. Time for fault tracingand replacement of a faulty unit shall be reduced to a minimum. The supervision shall alsocomprise the power supply system, the internal system bus and the ability of the central unit tocommunicate with different circuit boards.

The power supply system shall have test terminals for all the voltages used in the system.

The switchgear interlocking systems shall be hardware interlocking with parallel copper cabling; itshall be extremely reliable and safe.

Check-before-operate procedures shall be applied to the circuit breakers. Perfect collection andprocessing of all switchgear positions of the whole substation must be ensured at all times.Unclear information such as intermediate switchgear positions, switchgear faults, faulty data






transfer, etc., must never allow unintentional switching operations. Control, regulation andsynchronising functions shall deliver perfect collection and processing of all information of thesubstation. The information must be up-to-date and valid. Malfunction of control and regulationfacilities such as on-load switching of a disconnector, switching on in asynchronous state, etc.,shall be avoided. In case the station level control and regulation facilities fail, back-up controlshall be possible.

16.5.8.2 Auxiliary Supply110V DC shall be used for power supply, input and output contacts on the bay control units. Theunits shall take a voltage range of 36-312V DC.

The voltage bridging time shall be greater than 50ms and load on the station battery shall not bemore than 50W.

16.5.8.3 Binary Inputs

Potential-free Opto-coupler inputs are preferred.

Input voltage should be at least in the range of 90 to 312V DC.

The operating time shall be 1ms at most.

16.5.8.4 Signal OutputsMaximum operating voltage shall be at least 250V AC or DC

Continuous rating shall at least be 5A.

16.5.8.5 Analogue Inputs

The rated frequency shall be 50Hz and input current of 1A.

Thermal rating:

Current Circuit continuous 4A

10s 30A

1s 100A

Voltage circuit continuous 130V

10s 200V

16.5.8.6 Configuration and settings

The configurations and operator programs shall be in English.

They shall be done using an IBM compatible laptop with the recent operating system.

The operator program shall also be operated by remote control via a modem. Operating System, configuration and diagnosis software and necessary licenses shall be

required together with the necessary hardware.

16.5.8.7 Other information

Operating temperature range -10 C to +55 C (minimum range)

Humidity 93%, 40 C, 4 days (minimum)

Insulation test 2kV, 50Hz, 1min (minimum)






1kV across open contacts

Surge Voltage 5kV, 1,2/50 s

Leakage resistance >100M , 500V DC

Immunity to magnetic interference at power system frequencies shall be according

to IEC and EN 61000-4-8 (1998)

16.5.9 Uninterrupt ible Power Supply (UPS)

A UPS system shall be supplied consisting of an inverter connected to the 110V station batterywith static and manual by-pass switches connected to the AC mains supply. The load on theUPS shall be kept to an absolute minimum.

UPS load shall be supplied via the inverter during normal operation. Should an overload or faultoccur on the inverter feeding circuit the static by-pass switch shall automatically switch over tothe AC mains supply. The static by-pass switch shall be synchronised to the mains' frequency sothat an automatic change over does not cause an interruption to the load. Once normal supply isresumed the static by-pass switch shall change over to the previous position. For maintenancereasons the manual switch shall be capable of changing over the load without interruption ofsupply.

16.5.10 Spares

The supplier shall provide spares considered necessary for the bay control units, gateway andother equipment that the Employer may require to replace damaged components in order to bringback the system to full operation. The bidder shall include any special tools and test equipmentrequired for maintenance of the system. The spare parts list shall be subdivided into:

Short-term spare parts that are necessary for two (2) years of operation. These spare partsshall be included in the contract and shall comprise at least one spare module for suppliedequipment and basic tools for system maintenance.

Long-term spare parts that are necessary for ten (10) years of operation. These shall be

recommended.

16.6 Training

Factory acceptance tests and training on the installation, Engineering tools, operations anddiagnosis bay control units, HMI and communication equipment shall be required. Training on theSCMS shall be at manufacturer’s training facilities for 4 Engineers for minimum 2 weeks. Thetraining program shall be approved by the Project manager.

The Bidder shall provide complete documentation including circuit description, circuit diagramsand maintenance manuals. The manuals shall be in English.

Thorough transfer of technology shall be affected for all supplied equipment to cater for future

expansions.









Refer to Chapter 26




17. TECHNICAL SPECIFICATION FOR PROTECTION



Volume II – Section VI : Employer’s Requirements : Contract 16 - 132/33kV Substations and Bays

Chapter 17: Protection Systems

Page i Kenya Power and Lighting Company Limited Substation Bidding Documents – October 09

Contents

17 PROTECTION SYSTEMS ................................................................... 1

17.1 General .......................................................................................................... 1





17.5.1 General Requirements .................................................................................... 1

17.5.2 Relay Construction and Mounting ......... ......... ......... ......... .......... ......... ......... .. 3

17.5.3 Commissioning and Routine Testing Facilities ......... .......... ......... ......... ........ 5

17.5.4 Relay Settings .................................................................................................. 6

17.5.5 Main Protection................................................................................................ 6

17.5.6 Fault Clearing Time ........ .......... ......... ......... .......... ......... ......... ......... .......... ...... 7

17.5.7 Autoreclose ...................................................................................................... 7

17.5.8 Circuit Breaker Failure .................................................................................... 8

17.5.9 Busbar Protection ........................................................................................... 8

17.5.10 Trip Circuits ..................................................................................................... 8

17.5.11 Fault Recorder and Fault Locators ......... ......... .......... ......... ......... .......... ......... 9

17.5.12 Bus Coupler Bypass Tripping Logic ......... .......... ......... ......... ......... .......... ...... 9

17.5.13 Supervision ...................................................................................................... 9

17.5.14 132kV Transmission Line Protection .......... ......... ......... ......... .......... ......... ..... 9

17.5.15 Transformer Protection ......... ......... ......... ......... .......... ......... ......... .......... ....... 11

17.5.16 Breaker Failure relay protection Relay .......... ......... .......... ......... ......... ......... 13

17.5.17 33kV Distribution feeder Protection ......... ......... ......... ......... .......... ......... ...... 13

17.5.18 11 kV feeder Protection ................................................................................. 13

17.5.19 Protection, Control and Metering Panels ........ .......... ......... ......... .......... ....... 13

17.5.20 Synchronizing Equipment ............................................................................ 14

17.5.21 Signals and Alarms ........ .......... ......... ......... .......... ......... ......... ......... .......... .... 15

17.5.22 Indicating and Metering Instruments and Metering Transducers .............. 15

17.6 132/33 kV Substation Protection and Supervisory RequirementSchedule ..................................................................................................... 15

17.6.1 General ........................................................................................................... 15

17.6.2 Substation Signals ........................................................................................ 15

17.7 Testing and Commissioning ..................................................................... 17

17.8 Compliance with Specification .................................................................. 17






Page ii Kenya Power and Lighting Company Limited Substation Bidding Documents – October 09





Page 1 Kenya Power and Lighting Company Limited Substation Bidding Documents – October 09

17 PROTECTION SYSTEMS

17.1 General

This Chapter covers the technical requirements of Protection systems including relays an dofsupervisory requirements.

Equipment shall generally be in accordance with requirements under Chapters 2 and 3.

The relevant Technical Data Sheets in Chapter 26 shall be completed in full to verify or clarifycompliance or otherwise with these Employer requirements. All data will be filled out in the forms.






It is jointly the Contractors and manufacturer s responsibility to be familiar with any other climaticand physical conditions pertaining to the specific sites as defined in Chapters 1-3 and to allowfor all conditions in designs.



All equipment shall be designed, constructed and tested in accordance with requirements of thelatest version of the standards specified herein except to the extent explicitly modified in thisspecification:



17.5.1 General Requirements

The relays to be installed for the protection of transmission lines, transformers and otherequipment shall be of robust type, insensitive to changes of temperature, vibration, etc. Inputfrom the measuring transformers shall be based on 1A, 110 V AC. The Contractor shallendeavour to standardise the equipment by using as few different types of instruments, relays,switches and other devices as possible. Preference shall be given to numeric relays.

For the protection equipment supplied under this contract and its associated software, theSupplier shall provide a conclusive number of reference installations at similar voltage levels aswell as references for at least two years of operational experience in a HV substation.






All protection relays shall be fully numerical. The protection relays shall be separate devices fromthe bay control units. The relays shall indicate and store measured service values and faultevents. Main and back-up protections have to be done by different relays.

The scope of supply shall include two laptops including original software to commission and

reprogram all delivered protection relays. The Contractor shall complete all necessary TechnicalData Sheets in Chapter 26.

A dedicated OPGW (specified elsewhere in these specifications) shall be provided for thecoupling of the distance and differential protection relays to the remote end. The serial workinginterface for the asynchronous transmission shall have a Hamming distance of 4. The equipmentshall be selected to allow for 20% attenuation reserve in the end-to-end transmission. Allnecessary additional devices, plug connectors, conventional and short copper or fibre-opticconnections up to the terminals of the fibre optic cable are part of this supply.

The following shall be required for serial interfacing:

system interface, potential-free, suitable for asynchronous connection via local fibre opticconnection to the central systems;

all devices, connectors and fibre optic connections up to the SCMS;

operator interface such RS232/RS485 terminal shall be required for parametrising,setting, and retrieving of stored event records via hand terminal or PC.

The working and system interfaces as well as the associated interface devices shall withstand allinsulation tests as specified.

The device used shall have self-supervision facilities that include but not limited to the followingfeatures:

self-supervision of the main hardware components and of the serial communication to theremote end. The "device faulty" and "channel faulty" alarms shall be made available to theSCMS (Substation Control and Monitoring System)

Locally LED-indication;

"channel faulty" alarm which shall be time- delayed (1… 50s).

local LED indications (seal-in) or readable on the LCD display shall include:

o in operation (green)

o device faulty (red)

o channel faulty (red)

o direct transfer trip (red)

o trip (red)

o or readable LCD

resettable by local push button or via centralised SCMS

Typical alarms available at the SCMS shall include:

o device faulty

o channel faulty

o direct transfer trip

o trip

As a minimum the relays shall have the following functions/components:

disturbance and event recording, cyclic overwriting, min. event time 2s, with pre-faulthistory, transferable to the SCMS on request or retrievable menu-guided from the PC; the






event recording shall be time-tagged by an included real-time clock synchronized to theSCMS;

Settings, parameters and event records shall be stored in a non-volatile memory (with acapacity to store events for at least 100 successive events).

one-end test facilities, display of the phase and zero-sequence service currents.

external switch with the positions "in/out" (trip circuit interrupted).

heavy duty trip contacts suitable for the double-pole direct trip with station battery voltageof the main circuit breaker.

The Numerical Relays will be equipped with an RS232 Communication Port on the front tofacilitate connection to a Laptop. There shall be two extra ports at the rear forcommunication to Regional Control Centre and National Control Centre independently

Protection cubicles shall be of self-ventilating type and shall comply with all constructionrequirements laid down in the abovementioned civil works chapter. The Contractor shall ensure

that in the event of failure of the air conditioning system, the protective relaying systems and theirassociated signalling, monitoring, control and alarm equipment remain in full operation.

In his case, suitable heating elements in the relay cubicles, controlled by humidity detectors,must prevent any condensation while keeping the temperature inside the cubicle within theoperating limits of the devices.

17.5.2 Relay Construction and Mounting

The relays shall comply with the requirements of IEC 60255 and such national standards as maybe appropriate in the country of manufacture. Modular constructed equipment (example, rackmounted solid state relaying equipment) shall be tested as a complete assembly and details ofsuch tests shall be agreed with The Employer when details of the construction are known.

Particular attention shall be given to resonant frequency scanning. Constructional details shallsatisfy the following requirements as appropriate:

a) Means shall be provided to positively locate each withdrawable unit in the 'service'position. It shall not be possible to remove any unit without first rendering the relayoutputs inoperative.

b) Each protection relay, or protection scheme shall be provided with an adequatenumber of output contacts of suitable rating to carry out the prescribed trippingfunctions as may be necessary for the initiation of automatic reclosing or automaticswitching control, etc.. In all cases, the swell of the output contacts shall be not lessthan 50 ms and they shall have a rating appropriate to the maximum possible duty,due account being taken of the range of voltage variation in the d.c. supply source of

the associated circuit. For contacts intended to be used to directly energise circuitbreaker tripping coils the peak value of the permissible peak current shall be statedon the appropriate Technical Data Sheet in Chapter 27 by the Contractor/Bidder.Where appropriate, details shall also be given of the operating characteristics of anyreinforcing contactor and, in particular, the pick-up and drop-off threshold levels of aseries connected (current dependent) contactor. The Contractor/Bidder shall alsoquote the maximum breaking capability of the trip output circuit (in mA) whenassociated with an inductive burden having a time constant of not less than 40 ms ata rated voltage of 125 volts d.c..

c) All static protection relays shall be designed to withstand the high voltage interferencewhich is normally experience in high voltage switching stations. Static protections

which require an independent low voltage d.c. supply shall preferably used.c./a.c./d.c. converter power pack for this purpose. Separate power packs arepreferred for each individual discriminative relay unit.

d) If the power pack is separately housed from the relay unit(s) which it is supplying,






care must be taken that the cabling between the power pack and the relay unit isadequately screened and physically separate from all "power type" circuits associatedwith the CT, VT and d.c. tripping circuits. All interconnecting screened cables shallpreferably be terminated by plugs and sockets.

e) It shall not be possible to gain direct access by means of external connection to anylow voltage d.c. power supply without first removing an appropriate protective coversuitably engraved with a warning that high voltage tests shall not be applied. That is,there shall be a degree of mechanical segregation between the "Power type" circuitsassociated with the CT, VT and d.c. tripping connections and low voltage circuits.

f) All input and output terminals of the power packs which are connected to "powertype" circuits shall be subjected to the same overvoltage, impulse and interferencetests as specified for the static protection.

g) The low voltage supply to each discriminative relay unit shall be continuouslymonitored and an alarm shall be given whenever the voltage exceeds the limits forreliable protection operation.

h) In order to minimise the high voltage interference to acceptable level, the stationmulticore cables shall be screened and earthed according to the latest standards forhigh voltage switching stations.

i) Each relay, or relay scheme shall be provided with an adequate number of indicationsto facilitate post fault analysis including identification of the faulted phase and faultedzone, etc. Mechanically operated output indications are acceptable but considerationshall be given to other methods of presentation provided that:

i) Long term storage of the indication is not dependent upon an auxiliary supply.

ii) Means are provided to ensure that the indication is complete, e.g. relays whichare provided with lamp indicators must have lamp testing facilities.

iii) Each indicator, whether of the electrically or mechanically operated type, shallbe capable of being reset without opening the relay case.

iv) Each indicator shall be so designed that it cannot move before the relay hascompleted its operation.

v) Unless otherwise approved, indication shall only be given by the protection(s)which causes the fault to be cleared.

vi) All indication shall be clearly visible without opening of relay cases or relaypanel doors.

All relays which are of the hand reset type shall be capable of being reset without the necessity

of opening the case.Wherever practicable the design of the relay schemes shall be based on the "fail-safe" principle.For example, care shall be taken to ensure that loss of d.c. supply or an open circuit does notcause incorrect opening or closing of circuit breaker. Circuit breaker or isolator repeat relaysshould be of the latching type and a discrepancy alarm shall be provided to check correctoperation of the relays following a circuit breaker or isolator operation.

All tripping relays shall be of the heavy duty type suitable for panel mounting and shall haveoperating coils rated to a sufficiently high value that they are suitable to work in conjunction withseries trip flags. "Cut-throat" contacts, when provided on the relays, shall be delayed in operationsufficiently long as to ensure that the series flag relays, if fitted, operate correctly.

All other contacts on the tripping relay shall operate within the prescribed time for the particularcategory which shall not, in any case, exceed 10 milliseconds from the time at which theoperating coil of the relay is first energised.

The lockout tripping relays shall be of the latching type and shall be hand and electrically reset.






In order to achieve a high degree of security in function, the protection system of each highvoltage main component (lines, power transformers, shunt reactors, etc.) shall consist of twoseparated protection sets, main and back-up where applicable. The two protection sets shall bedivided into two electrically and mechanically separate parts by means of:

Separated DC power supply, Separated boards,

Separated current transformer cores,

Separated voltage circuits,

Separated tripping devices,

Separated cables,

Separated relay protection channels.

All primary faults which are of such magnitude that they jeopardise continued operation of the

grid, represent a risk to persons or could cause appreciable material damage to plant or to thesystem, shall be isolated. Also in the event of a single failure in the relay protection equipment,its supply of measuring quantities, auxiliary voltage, etc. or primary breakers shall be isolated.

All protection relays shall be mounted in 19" rack or enclosed in case and shall have silver platedcontacts. The relays shall be of the modular, plugged type. The plug mechanism shall be suchthat when the relays or part of the relays which are connected to the current transformer circuitsare pulled out, the circuits of the current transformers are automatically shunted.

Each relay protection shall have test facilities of a type enabling testing of the entire relaycombination when the protected part is in service. Furthermore it shall be possible to switch offthe tripping impulses by means of switches or links. Relays with integral test facilities or testblocks will be preferred.

Indications shall be provided on each individual relay to show if they have operated and tofacilitate analysis of the fault including identification of the faulted phase and faulted zone.Portable test equipment shall be provided to facilitate testing of the relays at site. For static typerelays, trip test facilities shall be provided.

All necessary intermediate current and voltage transformers, converters and auxiliary powersupply units shall form part of this supply.

17.5.3 Commissioning and Routine Testing Facilities

Each functional relay scheme shall be so arranged that operation and calibration checks can becarried out when the associated primary circuit(s) is(are) in service and form part of theoperational network. Adequate test facilities shall be provided at the front of the relay panel toenable the protective equipment and auto-reclosing equipment to be tested whilst the primarycircuit is on load, without having to disturb any wiring. Adequate facilities shall be provided at thefront of each relay panel to isolate all d.c. and a.c. incoming and outgoing circuits so that workmay be carried out on the equipment with complete safety to personnel and without loss ofsecurity in the operation of the switching station.

All test equipment required for commissioning and routine testing of the offered protectionequipment shall be provided and four complete sets (Hard copy) and one (1) soft copy handedover to the Employer.

This shall include such injection transformers, test leads and plugs as are necessary to carry outsecondary injection tests on each type of relay scheme and, for the more complex schemes,

such special test equipment as may be necessary to verify the accuracy of timing and verify theeffective operating characteristics of the equipment.

For solid state measuring equipment the Contractor shall list such tests and provide training asmay be required to carry out on-site investigations into the performance of individual modules or






printed circuit cards.

At least two complete sets of any special test equipment shall be included in this project togetherwith such additional connections, dummy extension boards, etc., as may be necessary.

17.5.4 Relay SettingsThe protection setting philosophy and policy as well as the system parameters requiredshall be provided by The Employer. The Contractor shall calculate the setting to ensuregrading within the new substation and also with the existing system setting. The settingscalculations shall be supplied three (3) months before the start of any commissioning forapproval. This is a hold point. The relay settings shall be applied to the equipment by theContractor, prior to making all commissioning tests.

17.5.5 Main Protection

The new overhead line feeder circuits shall be provided with fully duplicated main protectionsystem that comprises of:

Main 1- One set of numerical distance protection operating in permissive mode (PUTT).The Main1 shall incorporate directional earth fault protection operating in blocked mode.

Main 2- One set of optical fibre current differential protection, with integral distance protectionelements to provide Zone-2 remote busbar back up protection and Zone -3 remote circuit backup (if necessary). The current differential protection shall remain stable during current charginginrush and with the presence of steady state charging current.

Main 1 and Main 2 shall be provided by different manufacturers.

17.5.5.1 Distance Protection signalling

For distance relays, where the length of the OHL permits, the main distance protection shall

preferably be designed for direct interfacing to a pair of optical fibres for teleprotectioncommunication. Should line length be a limiting factor then a digital teleprotection signalling unitor Multiplexer shall provide the necessary teleprotection communications between circuit-endrelays. The distance protection should preferably be provided with an integral, two-way, high-speed, high-security intertripping channel, where energisation of an intertrip send optical isolatorof one relay will cause dedicated intertrip receive contacts of the remote relay to operate.

Alternatively, a separate intertrip channel shall be provided via dedicated intertripping equipment.

17.5.5.2 Current Differential Protection Signalling

Current differential relays shall be designed for direct interfacing to a pair of optical fibres toprovide the necessary digital communications between circuit-end relays. For OHL circuits whererelay to relay direct fibre connection cannot be provided, due to length or no OPGW, then digitalcommunication shall be achieved by connection to a Multiplexer.

The current differential protection should be provided with an integral, two-way, high-speed, high

security intertripping channel, where energisation of an intertrip send optical isolator of one relaywill cause dedicated intertrip receive contacts of the remote relay to operate.

In the case of relay fibre optic direct connection, the OPGW (if available) shall provide a pair offibres plus a pair of spares for each main protection.






17.5.6 Fault Clearing Time

The protection system plus the circuit breakers shall have fault clearing time of not more than 50

ms.

17.5.7 Autoreclose

Faults occurring on an overhead line feeder are mostly transient and following a short delay aftertripping the line can be reclosed and the supply of power re-established. The majority of transientfaults on overhead line feeders are earth faults that are usually the result of lightningstrikes,vegetation or animal contact. Following the initial fault, the insulation of the line is re-established once arc products have dispersed and the line can be re-energised.

Since earth faults are statistically the most common fault then single pole auto-reclosing can be

beneficial. The benefits of single pole auto reclosing are that synchronism between twogenerators is not lost as two phases still link the systems and the faulted phase can be reclosedwithout any check synchronism requirements. The disadvantages are increased complexity ofprotection and control circuitry as well and protection setting considerations for the period whenthe faulted phase is open. The circuit breakers also require individual tripping and closingmechanisms per phase. The power network principally uses AIS switchgear that is equipped withsingle-phase tripping and closing. It is for the above reasons that single-phase auto reclose isapplied throughout. However the option of choosing two or three phase autoreclose shall beprovided by means of a selector switch.

A single separate numerical auto-reclose relay is preferred and the reclose sequence initiated bymain protection.

The auto-reclose relay shall operate in a single phase auto-reclose mode (unless selectedotherwise) for all line faults detected in the protected zone with respect to current differentialprotection and instantaneous elements of the distance protection. A separate relay is specifiedand shall be provided instead of integral main protection and auto reclose as it permitseither main protection to be out of service without affecting the auto-reclose availability . Itis recognised that it may not be desirable for the network to operate with auto-reclose in service ifone of the main protections is out of service. In this case the network operators can switch theauto –reclose relay out of service if required. IN/OUT switching shall be available both locally atthe relay panel and by remote operation via the SCS system.

The Auto reclose scheme shall be one shot only and shall go to lockout mode if a second faultoccurs within the reclaim time following the first shot reclose.

The Auto reclose sequence shall be blocked by distance protection time delayed impedancezones, operation of main protection Switch-onto-fault (SOTF) function, operation of busbarprotection and circuit breaker failure protection.

Circuit breaker low stored energy signals shall inhibit the auto – reclose sequence until the elapseof a timer resulting in AR lockout. Should the stored energy recover before the elapse of the timerthen auto reclose sequence will continue.

In the case of three phase auto-reclose sequence, there is a possibility that the power systemmay be split and one part of the system may lose synchronism with respect to the other part. Anyresulting CB auto reclose, without a check synchronism reference may result in an out ofsynchronism closure that damages the power system both electrically and mechanically. Theseverity of the damage depends on the degree of out of synchronism at the instant of closure.For these reasons all three phase auto-reclose shall be performed with a check synchronism.

For existing substation where a central check synchronism relay is used, the availability of asignal from this scheme shall be investigated and if practical utilised. Alternatively, if the central






check synchronisation scheme cannot provide the necessary signals then an auto reclose relaywith an integral check synchronism feature can be provided and connected to busbar and linevoltage transformers.

An intertrip receive signal shall inhibit the AR sequence until either the intertrip signal is reset or a

persistent intertrip timer elapses and the AR relay goes to lockout.The circuit breaker at the line end that recloses first shall upon detection of a permanent faultissue a persistent intertrip that prevents the remote end CB from reclosing onto the fault.

The auto reclose relay shall be provided with a manual close inhibit feature that prevents AR fora settable period of time following manual CB closure e.g. following CB maintenance.

The Auto-reclose relay shall provide CB maintenance alarm and lockout functionality.

The auto-reclose relay shall be provided with indications and alarms for:-

In/out of service Auto reclose relay healthy Auto reclose in progress Auto reclose lockout Auto reclose complete

The alarms shall be available locally on the relay and via the SCS.

17.5.8 Circuit Breaker Failure

Each protection system includes the circuit breaker(s).Beyond the circuit breaker trip coils theduplication of the protection system ends. Circuit breaker fail protection shall be provided to caterfor the possibility of a single circuit breaker failing to clear a fault current when commanded to doso by either of the two main protection systems. The breaker fail protection shall initiate aninstantaneous re-trip followed by rapid back-tripping of other circuit breakers, as necessary, andwithin KETRACO S required 132kV back up fault clearance time of 300mS.

Note: In Kindaruma 132kV double busbar care shall to ensure mal-operation of the scheme isminimized. It is expected that;

two current check relays system is employed and both must operate beforethe time delays are energized.

Two time delay relays must operate before back-trip wires are energized

The circuit breaker failure protection shall be provided. This may be integrated with Busbarprotection.

17.5.9 Busbar Protection

The busbar protection scheme shall be a current differential protection, of numerical design.

The busbar protection shall include checking techniques to detect analogue input errors thatmight provoke an incorrect trip under load. In addition, the sensitivity of the busbar protectionshould be settable such that it cannot trip for any current measuring error under load conditionswhilst still providing adequate sensitivity under minimum plant conditions.

Note: For Kindaruma 132kV double busbar: There shall be Main busbar 1 (Main bus) and Mainbusbar 2 (reserve bus) busbar protection and shall be installed in two different panels. Checkzones shall be required for this particular scheme

17.5.10 Trip Circuits All trip circuits shall be duplicated with one group tripping the circuit breaker directly and the otherrouted via a trip relay with heavy duty contacts. The tripping relay shall be of high burden,






immune to capacitance discharge currents and leakage currents with at least 8 pairs of outputscontacts two of which should NC contacts. The Instantaneous operation, shall be t <12ms

All lockout trips shall be routed via a hand reset/electrical reset relay with heavy duty contacts.Closing of circuit breakers from substation control systems or local operation cubicle shall be

inhibited if the lockout trip relays are not reset. The trip circuit supervision shall be provided tomonitor each pole of each trip circuit at 132 kV with the circuit breaker in both the open andclosed position.

All DC/DC converter feeding protective relays shall have DC fail monitoring facilities.

An alarm shall be given to signal faulty trip circuits. The alarm shall be time delayed to preventoperation during momentary dips in the DC supply.

17.5.11 Fault Recorder and Fault Locators

Fault recorders and fault locators must be integral in line protection relays while other relays shallhave fault recorders and use the same input quantities as the main protection functions.

17.5.12 Bus Coupler Bypass Tripping Logic

Where a bus coupler is specified, the tripping signals of any bypassed circuit breaker shall beinstantaneously transferred to the bus coupler.

Electrical interlocks shall be provided to ensure that only one circuit breaker can be put onbypass at any one time. This is only possible through the reserve busbar where applicable.

The bus coupler protection shall consist of a 3-pole IDMTL overcurrent relay and one IDMTLearth fault relay, all with standard inverse characteristics.

17.5.13 Supervision

The supply shall include a system for remote supervision and data acquisition of protectionrelays, fault locators, and fault recorders. The software shall be installed on a central pc with„„Windows NT operating system. The centrally installed software shall make it possible tocontact the relays over the telephone network via modems installed in each substation. TheContractor shall supply and install the modems, connect the relays and test the complete chain ofcontrol.

All the protection relays shall support IEC 61850.

17.5.14 132kV Transmission Line Protection

17.5.14.1 Distance Protection

The principle design of the protection for 132 kV lines is shown on drawings for protectionschemes. A complete full scheme, fully numerical, high-speed operation distance relay suitablefor solid or resistance earthed power systems shall be provided. The relay must have thefollowing characteristics:

Independent zones of protection with at least one reverse measuring zone.

Independent high-speed overcurrent element for additional protection for close up faults.

Directional offset – selectable polygon or mho characteristic for all faults:

The following starting logic s should be included:

Overcurrent starting

Ground starting Under-impedance starting

Under-voltage starting






Voltage transformer supervision

Power swing blocking

System logic:

o Switch-onto-faulto Overreach zone

o Permissive under-reaching transfer tripping

o Permissive overreaching transfer tripping

o Blocking scheme

Directional Earth-fault Module

Overcurrent protection (Built-in local back-up function to the main distance relay)

Breaker Failure protection

17.5.14.2 Earth fault protection

Comprehensive directional Earth fault protection

17.5.14.3 Over and Under-voltage protection

Built-in voltage protection options

17.5.14.4 Automation

Synchro-check function

Single and 3-phase multi shot auto- reclosure

Metering

Built in instrumentation to indicate values of frequency, currents, voltages, vars, watts

17.5.14.5 Process supervision (may be integrated into Distance Relay)

Fault location with distance given in kilometres and as a percentage of line length

Integral disturbance recorder

Comprehensive fault and event logging with date and time tags

17.5.14.6 Self-supervision

Comprehensive self supervision and alarms

17.5.14.7 Operational control

Front panel user friendly menu driven man-machine interface including an LCD displayand a keypad

Front plate interface for local connection of a control unit (personal computer)

17.5.14.8 Combined Over-current and Earth-fault

Three-phase low-set overcurrent stage with definite time and inverse time characteristicfor time overcurrent protection

Three-phase high-set overcurrent stage and three-phase superhigh-set stage withinstantaneous function and definite time characteristic for short-circuit protection.






HV overcurrent protection. A back-up protection, 3-pole IDMTL relay with a standardinverse characteristic comprising three overcurrent elements with surge proofinstantaneous elements shall be provided.

The LV side of the transformer to be equipped with a second overcurrent protection. This

3-pole IDMTL relay shall only trip the LV breaker. Tertiary winding earth fault protection. 1-pole earth fault adjustable constant time

overcurrent relay located in the earthed phase.

Breaker locking out relays

The following protection signals will be supplied by the transformer manufacturers and shall beintegrated in the protection and alarm system.

Oil Level signals with at least two low-oil level output contacts, one for alarm and the onefor tripping.

Buchholz, gas operated signals (both for the transformer and the tap changer).The

protection will have two output contacts, one for alarm and the one for tripping. Over-temperature signals for winding hot spot and top oil. Two sets of alarm/trip contact

adjustable to close at any temperature between 60 0C and 140 0C.

A pressure relief device shall be provided for the main tank, complete with trip contactssuitably wired to the marshalling kiosk. The device shall be resettable after an operation.Details of the device shall be submitted with the offer.

17.5.15.1 Transformer Differential Protection

The relay shall have the following features:

Relay Must be of Numerical design

Pick up setting range, 0.1 to 0.5In Should incorporate a high-set Element with a setting range of up to 20In. Magnetising current inrush restraint Integral CT ratio compensation(0.1-2) and vector group compensation Measurement and indication on the MMI, of phase(HV&LV) ,differential and bias

currents. Storage of Fault records and Event records; the Fault flags should be accessible on

the relay LCD screen without opening the relay cover. Separate function that performs ovefluxing protection with alarm and trip functions. 5th harmonic restraint feature on the differential Element. Appropriate Dual Bias characteristic to ensure relay stability for heavy through faults

Should incorporate a disturbance recorder feature. Red L.E.D to indicate Tripping Relay Self diagnostic and Alarm feature Ability to Latch output contacts to prevent Transformer re-energisation before

carrying out investigations.

17.5.15.2 Transformer Restricted Earth fault (separate relay)

The relay shall have the following features:

Relay must be of Numerical type Relay should reject harmonics produced by C.T saturation The offer should include the associated stabilising resistor and voltage dependent resistor

(metrosil) Current setting range 0.05-0.8In Operating time < 25ms at 5 times the setting






17.5.16 Breaker Failure relay protection RelayThe relay shall have the following features:

Numeric design Circuit –breaker failure protection, single or three pole with or without current Three phase overcurrent detectors. Earth fault detector. 2 out of 4 check of current detectors Activation by auxiliary contacts Independently settable delay times for operation with and without current

“No current” condition control using the circuit -breaker auxiliary contacts Two stage delay, hence two stages of operation Trip command input. Necessary logic to determine breaker fail condition. Operator keypad with display Display of line measured current values Serial Interface Annunciation and storage of previous events. Self monitoring Pole discrepancy Flush mounting

LEDs to show phase and stage of operation.

17.5.17 33kV Distribution feeder Protection

The 33kV feeders shall have the following protection:

Main: Distance protection with Autoreclose integrated in to it.

Back- Up – Separate (from the distance) Overcurrent and earth fault relay

17.5.18 11 kV feeder Protection

The 11kV feeders shall have the following protection: Overcurrent and Earth fault. The relay shall also incorporate Sensitive Earth Fault among

other features.

17.5.19 Protection, Control and Metering PanelsThe contractor s bid shall have not less than the number of panel indicated below

17.5.19.1 Kindaruma 132/33kV P/S

132kV Protection and Control Panels

Minimum of four (4) protection panels

One (1) Control and metering panel

17.5.19.2 Mwingi 132/33kV substation






132kv Control and protection Panels

Minimum of four (4) protection panels


Transformer Control and Protection Panel

One (1) transformer protection panel

One (1) 33kv Incomer control and protection panel

33KV feeders control and protection

One (1) protection and control panel for two line feeders

One (1) for protection and control for bus coupler

One (1) metering panel for all the feeders

17.5.19.3 Garrissa 132/33/11 kV substation

132kv Control and protection Panels

Minimum of two (2) protection panels


Transformer Control and Protection Panel

Two (2) transformer protection panel

Two (2) 33kv Incomer control and protection panel

33KV feeders control and protection

One (1) protection and control panel for two line feeders

One (1) metering panel for all the feeders

11KV control, protection and metering in the same switchgear panels NOTE: Alllocal control from the panel shall be done through Bay Control Units (BCU). Refer Chapter16

17.5.20 Synchronizing Equipment

The 132kV line circuit breakers and the secondary side transformer circuit breakers shall havecheck synchronism (controlled closure) equipment.

Note: Kindaruma double busbar shall also have check synchronism between (controlled closure)between the incoming lines.

Closure of the circuit breaker shall only be possible when the phase angle, slip and voltagedifference between the measured voltages are within preset ranges. Permitted phase angledifference shall be adjustable in the ranger of 5 to 100 degrees, slip shall be adjustable in the







Refer to Chapter 26




18. TECHNICAL SPECIFICATION FOR COMMUNICATION




Chapter 18: Communication Equipment


Contents

18 COMMUNICATION EQUIPMENT ....................................................... 1 18.1 General .......................................................................................................... 1




18.5 Telecommunications .................................................................................... 2

18.5.1 General ............................................................................................................. 2

18.5.2 SCOPE OF WORK ............................................................................................ 2

18.5.3 Fibre Optic Ground Wire (OPGW) ..................................................................... 3

18.5.4 Terminal Equipment .......................................................................................... 5

18.6 Protection Signalling Equipment ................................................................ 7

18.6.1 General ............................................................................................................. 7

18.6.2 Alarms .............................................................................................................. 8

18.6.3 Protection Signalling Equipment ......... ......... .......... ......... ......... ......... .......... ... 8

18.7 Cables and Cable Racks .............................................................................. 9

18.7.1 General ............................................................................................................. 9

18.7.2 Technical Requirements ................................................................................. 9







18 COMMUNICATION EQUIPMENT

18.1 General

This Chapter covers the technical requirements for the communication equipment.

The communication equipment shall include facilities for communication from thesubstations to the respective Regional control centre(s) and the National Control Centre(NCC) in Nairobi.

All components and also the system shall be followed by a documentation describing itcompletely to the least serviceable part.

Any specialized apparatus considered necessary or recommended for installation, testing ormaintenance by the Contractor should be offered with full technical details.

The Contractor is expected to adequately train various personnel from the Employer in theinstallation, testing, commissioning and maintenance of the equipment.

All equipment supplied under this contract must receive formal type approval from theRegulator, Communications Commission of Kenya. The contractor has responsibility toacquire the type approval before shipment and installation of equipment.

Unless otherwise stated, all communication equipment shall be configured to operate from asubstation supply of 48 volt d.c.

The relevant Technical Data Sheets in Chapter 26 shall be completed in full to verify orclarify compliance or otherwise with these Employer requirements. All data will be filled outin the forms.

Mandatory spares as specified by employer and those recommended by the supplier shallbe included in the scope of supply.


The Plant shall be capable of operation under the general electrical parameters as specifiedin Sub-chapter 3.6.2.


The Plant shall be capable of operation under the atmospheric conditions as specified inSub-chapter 3.6.1.

It is jointly the Contractors and manufacturer’s responsibility to be familiar with any otherclimatic and physical conditions pertaining to the specific sites as defined in Chapters 1-3and to allow for all conditions in designs.



All equipment shall be designed, constructed and tested in accordance with requirements ofthe latest version of IEC standards or as herein specified except to the extent explicitly






modified in this specification.


18.5 Telecommunications

18.5.1 GeneralIn order to achieve the desired SCADA functionality telecommunication links based onFibre, shall be established linking the Substation Automation System (SAS) in newsubstations to respective control centres. Necessary engineering required for transmittingdata and speech signals to the Regional and National Control Centre(s) shall be established.

Tenderers are requested to submit with their offers the detailed catalogues, brochures andtechnical drawings with the specific items on offer clearly marked for the products theyintend to supply.

Tenderers must indicate on the specifications sheets whether the equipment offered complywith each specified requirement.

The tender documents shall be accompanied by Type test and Routine test certificates,certified by the National Testing or the National standards Institute of the country of origin.

At her discretion, all equipment shall be subjected to inspection by the clients Engineers orrepresentative at the place of manufacture where all routine tests on randomly pickedsample(s) shall be carried out in their presence. Test reports shall be completed for each

equipment and made available to the Client after the tests have been carried out.

All the dimensions and capacities of the equipment to be supplied shall not be less than thoserequired in these specifications. Deviations from the basic requirements, if any, shall beexplained in detail in writing with the offer, with supporting data such as calculation sheets,etc. The Procuring entity reserves the right to reject the products, if such deviations shall befound critical to the use and operation of the products.

The Tenderers are requested to indicate the shortest possible delivery period of each product.

18.5.2 SCOPE OF WORK

The scope includes detailed system design, manufacture, supply, installation, testing,commissioning, remedying of defects, maintaining the works during the defects liability

period and any incidental work necessary for the proper completion of the work inaccordance with this contract. Scope shall include integration of STM-1 OLTE to theexisting THE CLIENT Network Management System. In some cases there shall be need toupgrade existing Telecommunication equipment in order to achieve data and speech routingto Regional and National control centres. Survey and necessary preparation works on existingsystems, Equipment and substations to achieve specified functionality shall be in the scope of






supply. Contractors shall be required to submit for approval detailed design of system beforemanufacture.

In addition all substations shall be equipped with a Base Radio capable of communicatingwith the ASTRO trunking radio system for use during switching operations. Where OLTEs

are the terminal equipment, additional Ethernet port shall be established to cater for LANdata requirement. All stations shall be equipped with two (2N0.) digital (IP based) telephoneextensions originating from existing PAXes in Regional control centres. One digitalextension card for the PAXs including configuration shall be in scope of supply.

18.5.3 Fibre Optic Ground Wire (OPGW)The overhead earth wire shall be Fibre Optic Ground Wire (OPGW) with a minimum of 48strands. The fibre optic earth wire supplied shall be suitable for installation on transmissionline and shall be supplied complete with all necessary fittings and optical joint boxes. Theearth wire fittings and optical joint boxes shall be type approved.

The fibre optic earth wire shall comprise an optical sub-unit containing optical fibres overwhich shall be laid aluminium, aluminium alloy or aluminium coated steel strands. The cladsteel wire incorporated in fibre optic earth wire shall comply with the requirements of IEC61232. Shaped aluminium or aluminium alloy wire sections shall conform to therequirements of the appropriate IEC standard.

The optical sub-unit shall withstand the temperature rise associated with the specifiedlightning fault current flowing in the earth wire without damage. The fibre optic earth wire(OPGW) shall be manufactured in continuous lengths of not less than 2,000 m.

The overall system design of the fibre optic system shall meet the following minimumrequirements:

Single failure or degradation in any optical fibre not more than one year averaged over fiveyears;

Failures or degradations affecting more than one optical fibre, not more than one in ten years;

Increase in optical system transmission attenuation due to accumulated ageing and othereffects at the end of five years and not more than 0.05 dB/km.

Optical Fibres

Optical fibres shall be single mode fibre and shall conform to IEC 793-2-BI.

The fibre coating material shall be mechanically strippable. The optical fibres shall becapable of being jointed by fusion technique.

There shall be no measurable long term or short-term optical attenuation change due to thetemperature rise associated with a fault current flowing in an earth wire, or a lightning strikeon the earth wire.

OPGW Fittings






The fibre optic earth wire shall be with approved conductor fittings. The application of thesefittings shall not damage the earth wire or fibres, either mechanically or optically.At each support, a bypass device shall be provided to guide the cable around the earth wirefittings associated with the support.

Optical Joint BoxesOptical joint boxes shall be provided to protect the splice joint of optical fibres, either whenindividual lengths of the fibre optic OPGW, are jointed or between the fibre optic earth wireand the underground fibre optic cable.The joint boxes shall consist of external steel or die cast aluminium housing providing

protection to IEC 529 IP 44 and an internal die cast aluminium or high impact plastic ABS box to IEC 529 IP54The external housing shall be designed so that the rainwater is directed away from the doorand there shall be no water ingress when the door is opened.The joint boxes shall be supplied complete with all fittings to secure and seal the cable in thegland plates or blank the unused spigots. The cable cleats to secure the fibre optic OPGW orunderground cable shall be fitted inside the box. The cleats shall not have a detrimental effecton the performance of the optical fibres when tightened to the recommended torque.The top and bottom of the joint box shall be vented and the vents provided with the verminshields.The box shall be supplied complete with internal splice cassettes to accommodate therequired number of splices. The glands shall be fitted to accommodate either the fibre opticOPGW or underground fibre optic cable.

Fixing ClampsA bolted clamping system shall be used to attach the OPGW to the inside of the support,without drilling or modifications to the support steel work. The attachment clamps shall becapable of being attached and detached from the support, without affecting the OPGW.Fixing clamps shall be made from a suitable grade of aluminium alloy complying with therequirements of BS 1490 and / or BS EN 1676. Bolts shall be made from mild steel gradeS275JR to BS EN 10 025. Bolts and nuts shall be ISO Metric Black Hexagon to BS 4190 andshall unless otherwise specified be threaded ISO Metric Coarse Pitch to BS 3643: Part 2,Tolerance Class 7h/8g.

Non – Metallic Underground Fibre Optic Cable

The fibre optic cable shall be circular in cross section and shall be designed so that any cablestrain is so directly imported on the optical fibres. The cable shall not include any metalliccomponents to prevent high-induced voltages when used in switching or substationcompounds.

Protective TreatmentFibre optic earth wire

Where two layers of wire strands are provided over the optical sub-unit, the external surfaceof the optical sub-unit and the inner strand layer shall be greased, using approved conductorgrease.

Ingress of Moisture

The cable shall be capped before shipment to prevent the ingress of water.






GeneralThe supplier of the OPGW shall be responsible for the supervision of installation by theContractor; to ensure that system reliability requirements are met.

WorkmanshipThe Contractor shall ensure that the fibre optic cable are not strained or damaged either

mechanically or optically during stringing and/ or jointing.Fibre optic joints

Optical fibre joints in the OPGW, or between the OPGW and the non-metallic undergroundfibre optic cable, shall be housed in optical joint boxes. The joint boxes shall be locatedimmediately above the anti-climbing device for convenient access by technical personnel. All

joint boxes shall be earthed to the support steel work using approved multi-wire / multi-strand flexible aluminium earth bond.

18.5.4 Terminal EquipmentThe offered terminal equipment shall be based on SDH technology with minimum capacityof STM-1 capacity. The SDH (STM-1) multiplexer shall be installed in racks that are EMCcompatible and suitable to work in HV system environments.

The MUX shall be based on the basic transmission Bit Rate of 155.520 Mbit/s (STM-1). Itshall be in accordance with the latest ITU-T SDH recommendations such as: G.703, G.704,G774, G.783, G.784, G.785, G.811, G.812, G.813, G.823, G.825, G.826 and M.3010.

The equipment shall be able to perform both, multiplexing and line terminating functions.The SDH Equipment (Terminal Equipment, Add/Drop Multiplex, Synchronous DigitalCross-Connect) to be offered shall meet the following requirements:It shall have at least all the functions outlined in ITU-T G.783.The PDH electrical tributary interfaces to the SDH equipment shall conform to ITU-T G.703.The SDH electrical and optical interfaces shall conform to ITU-T G.703 and G.957.The cross-connect offered shall be capable of providing non-blocking connection betweenvirtual containers.The Optical Power to be offered shall be such that under normal operating condition, theBER of the system at the receiver is better than 1x10-10. Error performance versus thereceive signal shall be verified during the factory acceptance tests.

The multiplex structure shall conform to ITU-T G.707. Details of the Multiplex structure for

the offered equipment including the usage of the overhead bits shall be detailed with theoffer.

The synchronous optical interface protection shall be achieved by having 1+1 protection.The laser shall automatically cut-off when the link is disturbed. Redundant cross connect,where failure on either one shall not cause link outage, and path protection on the trafficinterface and the 2 Mbit/s levels shall also be provided.Timing and synchronization shall conform to ITU-T G. 783, G.811, G.812 and G.813.Timing references, number of timing references available, switching time to a differenttiming reference, type and level of clocks shall be stated in the offer.The equipment shall automatically switch to another clock if the reference timing is lost and

automatically revert back upon restoration. The accuracy of the internal clock as well as thedetails of the clock signal distribution shall also be stated in the offer.






The equipment shall be capable of diverting timing references between the STM-1, 2 Mbit/sand G.703 tributary interfaces.The SDH equipment shall be wired for the full STM-1 capacity, however equipped under thescope of this specification to receive at least four (4) PCM tributaries as specified below.However, if higher PDH signals other than the 2 Mbit/s are required to be routed through, the

same shall be possible just by adding the respective interface cards and no extra wiringneeded. It shall have 2 Mbit/s outputs where it can directly be connected to digital telephoneexchanges or teleprotection equipment.The jitter and wander tolerance for PDH and SDH interfaces shall conform to ITU-T G.823and G.825. Jitter and wander characteristics of SDH multiplex and line equipment shallconform to ITU-T G.783.The Contractor shall submit the details of the power budget calculations stating the following(based on 0.25 dB/km optical fibre attenuation at 1550 nm):Transmitter PowerMinimum receive Signal @ BER 1x10 -10Connector LossRepair Splice LossPower Penalty (Chromatic dispersion and LD reflection Loss)Maintenance Margin (> 2dB)Other LossSystem MarginThe SDH equipment to be offered shall provide the followings:A data communication channel to the Telecommunication Management Network, inaccordance with ITU-T G.773 for the purpose of integration of the new equipment into theTelecommunication Network Management System.A Craft interface in accordance with ITU-T G.773 to allow a local terminal to access the

network element.An engineer order – wire which shall have conference and selective calling features.Performance monitoring in accordance with ITU-T G.784 and G.826.Optical safety as per ITU-T G.783.

The alarm functions shall include but not limited to:Alarms classified as critical, major, minor, and information.Indications of loss of incoming signal.Visual and audible indication of alarms.Test function of alarm indicators to ensure workability of alarm indicators.Alarm functions shall be detailed by the Contractor, e.g. if implemented in

Telecommunication Network Management System.

Test functions of the equipment shall include as a minimum:

Transmit output

Receive Sensitivity

BER

Protection switching

Engineer Order-wire

Alarms






Supply Voltages

Test loops

The Contractor shall give details of all other functions available on the equipment / system.

The equipment shall have a proven record by submitting a reference list, that it has beeninstalled and operated in similar environment.

The power supply voltage and range shall comply with the characteristics of the DCsystem, the rated voltage being 48 Volt DC 15.SCADA and voice communications,including all necessary interface cards. This will provide for new protection. SCADAand voice signals installed under this project as well as any existing services whichthe client required to be carried on the optical fibre.

Lead in cable shall be provided at the new Substation to connect the OPGW to the terminalequipment.

DC power supplies will be provided at the new substation.

SPEECH EQUIPMENT

It’s proposed to connect two remote extensions from this excha nge to each of the newsubstation through the proposed communication Link. Seller shall provide the Telephonesets at the new substations

18.6 Protection Signalling Equipment

18.6.1 General

The teleprotection equipment shall be of a modular construction using solid-state devices.The unit shall be designed to fit into either a designated teleprotection panel, or beaccommodated within the slot in the BME or multiplexer rack. This would contribute to thecost effectiveness and flexibility of the system.

The equipment must able to transmit permissive, blocking and direct tripping commands.These commands shall be transmitted in full duplex within the PLCs audio frequency bandwith the use of a guard signal to safeguard against false tripping. At least four commands

shall be made available.Transmit and receive trip counters shall be available on the front panel of the equipment.These will be used to verify the receipt of all transmitted trip commands from the oppositestation.

The equipment must incorporate in-service auto-test facilities to continually monitor andreport the current status of the teleprotection link. In addition, comprehensive local andremote diagnostic test facilities shall be provide, with facilities to initiate testing from eitherend of the link. These shall facilitate measurement of parameters from the panel and assistin localizing faults for ease of maintenance. The results of all test or fault conditions shall bedisplayed on the front panel of the equipment, as well as bring up alarms where pertinent.

The method of modulation of the command signal must be described by the Contractor.






18.6.2 Alarms

Any malfunction or incorrect operation of the equipment shall raise an appropriate alarm, inthe relevant urgent or non-urgent category. The alarm conditions shall also be transmittableusing potential free relay contacts. Both visible and selectable audio indications are to beprovided for all alarm conditions.

18.6.3 Protection Signalling Equipment

Standard IEC 834 – 1

Transmission mode Duplex

Available commands Blocking

Permissive tripping

Direct tripping

Normal Transmission Times Blocking < 14ms

Permissive < 20ms

Direct < 16ms

Minimum number of commands 2

Alarm outputs 2 common alarms N.O. or N.C.

1 receiver alarm N.O

1 transmitter alarm N.O

Alarm delays 50ms to 10 sec adjustable

Alarm conditions of guards signal poor signal to noise ration

Auto-loop test failure

Excessive command duration

loss of supply voltage

PLC not ready to operate

Operating temperature -5 degrees to + 45 degrees Celsius

Humidity Humidity

Test voltages (IEC 834-1)

Relay interfaces 2kV rms/50 Hz/1 min

Unblocking outputs andalarm interfaces

5kV/1.2/50 microsecs

2.5kV longitudinal

1.0kV transverse

Power Supply Voltage 48 V DC nominal






Isolation test voltage 500 V/1 min, (IEC 495, 7.1.1)

Level boosting 0 to 15 dB

Frequency stability ± 0.1 Hz

18.7 Cables and Cable Racks

18.7.1 General

a) This chapter covers the technical requirements of the external cables andappurtenance, cable laying, supply and erection of cable racks, etc., for allinstallations described under these Specifications

b) The supply and installation of the internal cables between the various parts of

equipment shall be included in the Chapter in which the relevant equipment isspecified.

c) For calculation of the length of cables, cable racks, etc., the Tenderer shall usethat measurements computed from the Drawings. No alteration in the lump sumprices shall be made due to possible rearrangement of any installation, changesin the building constructions, or any other reason, which may influence thequantity of cables and appurtenances to be supplied.

d) If, however, a considerable change in location of a switchyard should be made,the prices shall be reduced or increased in proportion to the amount of reductionor increase in the distance between switchyard and the building. No priceadjustments shall be made for deviations of less than 25 metres.

e) No joints shall be permitted for all between the various parts of equipment. Allaccessories shall be provided as part of the project, such as potheads,galvanised and painted steel supports, clamps, etc.

18.7.2 Technical Requirements

18.7.2.1 Cables

a) The design, manufacture, rating and testing of all cables shall comply with theprovisions and requirements of the applicable IEC recommendations,supplemented by recognised national standards if necessary.

b) 45 oC maximum design ambient temperature shall be applied for all cablesinternally in the switchyard, between the switchyard equipment and the controlbuilding and inside the control building.

c) All cables shall be of termite proof design, e.g. by brass tape or equal approvedtechniques.

d) Wherever the risk of inductively transferred disturbances during abnormal(short-circuit, earth fault) conditions as well as during normal conditions exists,the cables shall be screened.

e) In order to have a minimum number of types of cables, all cables shall bestandardised as much as possible as regards cross-sections, number of coresand marking of cores.

f) The phase colour identification code to be applied shall be supplied to theTenderer shortly after the commencement of the Project.






g) For the three-phase low-voltage system, four wire grounded neutral system shallbe used.

h) The low voltage power cables (AC and DC) and all cables for control, measuring,etc., shall be PVC insulated and PVC-sheathed with an earthed concentriccopper screen. The conductors shall be of electrolytic copper.

i) Further requirements are stated in Section 2-I, General Specification of Works,“Terminal Blocks and Wiring ".

18.7.2.2 Cable Layin g

a) The main guidelines and general requirements for the cable laying are stated inSection 2-I Clause 2.15.5, General Specifications, (Cable Laying and Routing.)

b) Medium-voltage, low-voltage power cables and control and measuring cablesshall be segregated from each other throughout the plant.

c) The cables shall be laid in an orderly manner and crossings in the same planeshall be avoided.

d) All cables shall be laid on cable racks where they are not running in cable ductsor trenches, or in protecting tubes.

e) The cable racks shall be designed to allow the laying of the cable from theside(s) without pulling through. All racks and fixing devices shall be hot-dipgalvanised.

f) The Tenderer shall supply trenches and conduits of concrete.

g) The last section of a cable on the switchyard may be laid in a conduit or a pipe;they shall be laid in such a way that cables easily can be exchanged withoutdigging.

18.7.2.3 Diagrams and Calcul ation s

a) The Tenderer shall deliver cabling plans and diagrams showing each cableconnection.

b) Drawings for the cable racks, fixing features, etc., shall also be provided by theTenderer.

c) The Tenderer shall in this Project give detailed information about the differenttypes of cables proposed.

18.7.2.4 Tests

Factory tests and site tests shall be performed in accordance with the applicable IECrecommendation.

All power cables of sizes 240 sqmm and above shall meet the requirements of the followingadditional tests and type tests may be conducted to prove their capabilities.

Short time current test on conductor(s)

Short time current test on armours(s)

Type test certificates shall be submitted on request.

18.7.2.5 SPA RE PA RTS

The bidder shall include any special tools and test






The Contractor shall furnish a list of recommended spare parts and test equipment for thefibre and OLTEs. The spare parts list shall be subdivided into:

Short-term spare parts that are necessary for two (2) years of operation. These spareparts shall be included in the contract and shall comprise at least one spare module forsupplied equipment and basic tools for system maintenance.

Long-term spare parts that are necessary for ten (10) years of operation.

18.7.2.6 TOOL S AND TEST EQUIPMENT

The bidder shall include special tools and test equipment needed to maintain the fibre(including OTDR and splicing Kit), PLC, Radios and OLTEs over their expected lifetime.Bidder shall provide relevant technical data/pamphlets for all the items. The test kit shallinclude necessary laptops and all equipment applications and their licenses.

The test equipment and other special tools proposed shall be of the same type as used bythe contractor for erection and commissioning. The test equipment shall not however beavailable to the contractor during erection and commissioning.

18.7.2.7 DOCUMENTATION:

a. The Contractor shall provide all necessary drawings, design specifications,design details, operation and maintenance manuals. All manuals and As-Built-Drawings documents shall be supplied in three hard copies and asoftcopy in PDF.

b. The following documentation should be provided for the system in thecourse of the project. It shall be consistent, CAD supported and of similarlook/feel:

c. Control Room Layout

d. Single-Line Diagram

e. Block Diagram

f. Circuit Diagram

g. List of Apparatus/ Equipment

h. List of Labelsi. Functional Design Specification (FDS)

j. Test Specification for Factory Acceptance Test (FAT)

k. Logic Diagram

l. List of Signals

m. Operator’s Manual

n. Product Manuals

o. Calculation for uninterrupted power supply (UPS) dimensioning

p. Concept and contract for maintenanceq. It is necessary to present the technical description and the technical data






for the whole system and for any equipment and function

r. Time plan for the project realization.

18.7.2.8 TRAINING:

The Contractor shall provide 1 week training for four THE CLIENTstaff at the supplier’s manufacturing premises on eachTelecommunication type of equipment supplied and on site duringinstallation works. The scope of each service shall be given.

18.7.2.9 TESTING

The formal stages of testing to be performed fall into the following three categories:

Type Tests Equipment shall pass these tests in order to be accepted for useunder this Contract

Factory Acceptance Tests (FAT) Systems shall pass these tests before they maybe shipped to site. The employer shall witness FATs unless he waives this inwriting. FAT shall be carried out for fibre, SCSMS and OLTE

Site Acceptance Tests (SAT) Systems shall pass these tests before they may beput into operation and before they are Taken Over

18.7.2.10 SYSTEM AC CEPTA NCE

The System will be accepted if both:

The System and all items of equipment have successfully completed all the specifiedtests

All failures, problems and reservations noted during the tests have been corrected to thesatisfaction of the client

If either of these conditions has not been complied with, then the necessary correctiveaction shall be agreed between the Contractor and the client.


Refer to Chapter 26




19. TECHNICAL SPECIFICATION FOR METERING




Chapter 19: Indicating and Metering Instruments and Transducers


Contents

19 INDICATING, METERING INSTRUMENTS andTRANSDUCERS ................................................................................. 1

19.1 General .......................................................................................................... 1




19.5 Indicating instruments ................................................................................. 2

19.6 Tariff Metering .............................................................................................. 2








19 INDICATING, METERING INSTRUMENTS and TRANSDUCERS

19.1 General

This part of the specifications covers the design, manufacture, supply, installation, testing andcommissioning of a metering system, suitable for proper and accurate operation and supportmaintenance of each High Voltage substation.The technical characteristics of the control and monitoring system are described below.

Additional technical data is given in Chapter 26.

All materials and parts which are not specifically mentioned hereinafter but which are necessaryfor erection, assembly and operation of the equipment shall be supplied and are deemed to beincluded in the scope of supply for this subsection.

The offered system shall be suitable for operation under environmental and electrical conditions(including electrical discharge and disturbance level) prevailing in high-voltage substations.

The equipment shall be installed in steel sheet cubicles with hinged frames and glass doors,having a protection degree of IP 52.

The complete and detailed scheme of control, protection, alarms, etc. offered shall carefullyconsider the future extension of the plants.

Only experienced and technically capable equipment manufacturers will be accepted. In order toprove their technical capabilities, Contractors/Bidders shall present the following documents withtheir Bid:

block and functional diagrams of the proposed control scheme;

technical specifications and description of the systems, catalogues of the equipment anddevices to be used;

lists of the equipment contained in the panels;

digital control system layout;

brochures and references of the Manufacturer supplying the control system.

The equipment shall be pre-assembled and pre-programmed at the Supplier's workshop. It isunderstood that all necessary auxiliary facilities, devices and services will be provided, i.e.equipment for generation of data base, for programming and testing, for adjustments andparameter settings, displays, etc., even if not specified in detail here in.

The design, manufacture, rating and testing of all cables shall comply with the provisions andrequirements of the applicable IEC recommendations, supplemented by recognised nationalstandards if necessary.

45o

C maximum design ambient temperature shall be applied for all cables internally in theswitchyard, between the switchyard equipment and the control building and inside the controlbuilding.



19.3 Particulars of EnvironmentThe Plant shall be capable of operation under the atmospheric conditions as specified in Sub-chapter 3.6.1.






It is jointly the Contractors and manufacturer ’s responsibility to be familiar with any other climaticand physical conditions pertaining to the specific sites as defined in Chapters 1-3 and to allowfor all conditions in designs.

Particular attention should be paid in the design of all equipment to ensure that there is nodamage to working parts or insulation through the ingress of dust, insects, vermin which areprevalent for long periods in the year.


All equipment shall be designed, constructed and tested in accordance with requirements of thelatest version of IEC standards or as herein specified except to the extent explicitly modified inthis specification.


19.5 Indicating instrumentsThe indicating instruments shall be of the dial type which is easily legible, with black graduationsand numerals on a white background. The instruments shall have a dimension of 96 x 96 mmand suitable for flush mounting. The error of the instruments shall be maximum 1.5% reckonedon the total length of the scale. All instruments shall be of a narrow frame type. The integratinginstruments (meters) shall be installed in the control room board and shall have caseshermetically sealed against moisture and dust. The accuracy shall be class 0.5.

The metering transducers (converters) shall be installed in the boards and shall be suitable forconnection to the potential and current transformers. The cases shall be hermetically sealedagainst moisture and dust.

For the existing sub-stations the transducers may be installed in a separate panel instead of inthe existing board if that is the most suitable arrangement.

The W and VAr transducers shall be of the three-element (three-wattmeter) type when connectedto primary systems with grounded neutral. The voltage transducers shall measure phase-phasevoltage, one reading is sufficient.

The transducer output shall be an impressed DC current of 0-10 mA output. The maximummeter reading at the receiving end shall be equivalent to 30% overload of the source value. Thepermitted resistive load shall be at least 1000 ohms. The accuracy class shall be minimum 1%.The auxiliary voltage, if required (preferably not) shall be 110 V DC.

W and VAr transducers and meters for transmission lines, shall be such that the direction of thepower flow is indicated by negative direction towards the substation and positive direction out of

the substation. Wh and VArh meters shall register power irrespective of the direction of powerflow.

The scale on the different types of instruments shall be proposed by the Contractor/Bidder andbe subject to approval by the Employer/Project Manager.

19.6 Tariff Metering

The Contractor will supply, install and commission a free standing Tariff Metering panel completewith static energy meters.

Every 33kV outgoing line shall have one tariff meter, Ammeter and Ammeter selector switch. Onefree standing panel shall house all the tariff meters for the 33kV outgoing lines. The panel shallhave test terminal blocks for each meter and all other accessories.

The tariff meters shall conform to the requirement of IEC 61334-4-4-1(DLMS Standard protocol).






Unless otherwise specified, the latest revision, edition and amendments shall apply. In case ofconflict, the provision of this specification shall take precedence.

The meters shall conform fully to IEC 60687 for class 0.2S Energy Meters and any other relevantspecifications.

The meters shall be programmable and relevant software and connection cable to laptop shall beprovided. Meters complying with IEC 61334-4-4-1(DLMS Standard protocol) shall be preferred.

The meters shall have memory and be capable of storage of at least 12 months load profile andother data e.g. free zed Monthly readings.

The meters shall be capable of bi-directional metering so as to record faithfully, both export andimport quantities. The accuracy shall be as per IEC 60687 in both directions.

The quantities to be displayed shall be determined by the user through use of software that shallbe provided. The meters shall be configurable for use in three phase 3/4-wire networks systemsas follows:-

3x /110V, /5 (1) A

The meters shall be usable on phase voltages of magnitudes ranging from 100V to 500V, 50 Hz

and shall have voltage-surge protection that meets IEC 60687 specifications.The meter must have pulses output for interfacing with Scada

The meters shall be for flush panel mounting.

The meters shall have a non-volatile memory so as to ensure no loss of data during powerfailures. Security passwords and switches shall be provided to prevent unauthorizedprogramming of the meter.

The meters shall be suitable for operation in any part of the Republic of Kenya where the climatevaries largely from temperatures between -5 and 40 Degrees Celsius and relative humidityreaching 95% in some parts. Operating altitudes ranging from sea level to 2200 metres abovesea level.

The meters shall support multi-tariff metering.

The Meters shall incorporate instrumentation for the following measurands:-

MW; MVAR; MVA; p.f.; Phase Currents; Phase voltages and the angle between individual PhaseVoltage and corresponding phase current. These measurands shall be visible on the Meterdisplay.

The meters MUST have a capability of freezing billing readings on any selected date of themonth.

The meters will measure maximum demand for MW, MVAR and MVA and these will beaccessible on the Meter display. The Demand integration period will be programmable.

The CT and VT ratios shall be programmable.

The meters shall have an accurate internal quartz controlled clock. It should be possible to resetthe clock without loss of billing data.

The supplier shall show proof of ISO 9000 and ISO 14000 standards compliance.

The meters shall be provided with adequate sealing facilities to prevent tampering.

The nameplate and meter details shall be clearly marked using materials and colours that aredurable and indelible.

In addition to requirements of IEC 60687 the name-plate shall carry the following particulars:

a) The inscript ion “The property of KETRACO .”

b) Owner’s serial numbers as directed with a minimum 5mm figure height.

c) Year of manufacture, accuracy and rating values






The meter base cover shall be of non-metallic, non-hygroscopic, flame retardant, polishedmaterial having high impact-resilience and low dirt absorption properties.

The front cover may be of translucent material with a clear transparent front.

The meter shall have a minimum of three sealing - provisions for the meter body, terminal coverand front cover (where applicable).

The meter terminal cover shall be the normal short length with provisions of easy bottombreakage for cable entry. The terminals shall be of bottom entry.

The accuracy shall be Class 0.5 ’

The meter errors shall comply with the requirement IEC 60687 and shall be adjusted at themanufacturer’s works to be within ± 5% between low and high load and shall exhibit goodstability.

The meter shall have a warranty against any defects, which may develop due to faulty material,calibration, transportation or workmanship for a period of not less than eighteen months from thedate of delivery. All defective meters shall be replaced at the supplier’s cost.

The following drawings and information shall be required with the tender:

a) Meter drawing giving all the relevant dimensions.

b) Wiring diagrams.

c) Description leaflet including details of programming of the meters

d) User’s and service manuals.


If the technical requirements are not met or the performance of the equipment during test do notmeet the guarantees stated in the technical particulars subject to tolerances specified in relevantIEC Standards, the Employer shall have the right to reject the faulty component or theentire item. The Contractor shall replace the same in full compliance with the specification.


Refer to Chapter 26




Chapter 20: Construction Requirements


Contents

20 CONSTRUCTION HEALTH and SAFETY REQUIREMENTS ............. 2 20.1 Contractor’s Responsibility on Health and Safety at Work ...................... 2

20.2 Control and Supervision of Health and Safety at Work ............ ............. ... 2

20.3 Security Measures ........................................................................................ 3

20.4 Housekeeping ............................................................................................... 4

20.5 Permit to Work (PTW) .................................................................................. 5

20.6 Electrical Safety ............................................................................................ 5

20.7 Fire Prevention ............................................................................................. 5

20.8

Personal Protective Equipment (PPE) ............ ............. ............. ............. ..... 6

20.9 Noise Control ................................................................................................ 6

20.10 Signage, Notifications, and Barriers ............. ............. ............ .............. ....... 6

20.11 Contractor’s Equipment and Lifting Gears ................................................ 6

20.12 Area of Work ................................................................................................. 7

20.13 Confined Space Entry .................................................................................. 7

20.14 Working at Height ......................................................................................... 7

20.15 Working Over/Near Water ............................................................................ 7

20.16 Lighting and Ventilation............................................................................... 7

20.17 Excavation and Shoring............................................................................... 8

20.18 Welding, Cutting, and Grinding ............ ............. ............. ............. ............. ... 8

20.19 Compressed Gas Cylinder and Pressure Vessel ............ ............. ............. . 8

20.20 Hazardous Materials .................................................................................... 8

20.21 Material Storage at Site ................................................................................ 9

20.22 Environmental Obligation ............................................................................ 9

20.22.1 MSDS (Material Safety Data Sheet): .......... ......... ......... ......... .......... ......... ....... 9

20.22.2 PPE (Personal Protective Equipment): ......... .......... ......... ......... .......... ......... .. 9

20.22.3 Disposal and Spillage: ......... ......... ......... .......... ......... .......... ......... ......... .......... 9

20.22.4 Removal of Trees and Ground Vegetation: ......... ......... ......... ......... .......... ... 10

20.22.5 Activity Which Emit Dust Particles: .......... ......... ......... ......... .......... ......... ..... 10

20.23 Waste and Scrap Management ............. ............. ............. ............. ............. . 10

20.24 Employment ................................................................................................ 10

20.25 Emergency Response Plan (ERP) ............ ............. ............. ............. .......... 11






20 CONSTRUCTION HEALTH and SAFETY REQUIREMENTS

20.1 Contractor ’s Responsibility on Health and Safety at Work

The Contractor shall be responsible for ensuring, as far as practicable, the safety, health, andwelfare at work of all his employees in accordance to the Occupational Safety and Health Act(OSHA) 2007. In carrying out the works, Contractors shall comply with all relevant KenyanNational legislation, Statutory Regulations, Safety Rules; etc. which shall include but not limitedto the following including any amendments:

i) Electricity Supply Regulations 1988

ii) The Electricity at Work Regulations 1989

iii) The Factories and Other Places of Work Act Chapter 514

iv) Petroleum Safety Measures Act 1974

v) Environmental Management and Coordination Act (EMCA, 1999)

vi) Public Health Act Cap 242

vii) Fire Act 1984

viii) Uniform Buildings By-Laws 1983

ix) Employees Social Security Act and regulations made under the Act

x) KPLC Safety Instruction (Mechanical), latest edition

xi) KPLC Safety Rules (Electrical), latest edition

The provisions of Sub-chapter 3.14 Contractors Responsibilities shall be complied with.

The Contractor shall have his own Safety Management Plan for their employees and equipment.

A copy of such plan shall be submitted to the Project Manager at the commencement of work.The Contractor shall have a Safety Training Programme for their employees. Induction Trainingshall include hazard identification, use of Personal Protective Equipment (PPE), accidentreporting, interpretation of safety signs, understanding of safety regulations, CPR, First Aid, andother relevant training for site safety.

The Contractor shall issue regular safety reminders in the form of fliers, posters, banners,notices, safety suggestion box scheme, video presentation etc. to install safety awareness.

Workers shall be reminded on current safety issues on a daily basis prior to starting work.Supervisors shall inspect tools and PPE after the meeting.

The responsibility of the Contractor is not only to ensure the safety and health of his employees

but also the safety and health of his Sub-Contractor in abiding to the laws, Statutory Regulations,and Safety rules and regulations. The Contractor shall ensure that his Sub-Contractor isinformed, has understood, and abides to all laws, Statutory Regulations, and Health and Safetyrules and regulations at all times. The Contractor and his Sub-Contractors shall also be fullyaware of their responsibilities and liabilities as covered in the conditions of Contract.

20.2 Control and Supervision of Health and Safety at Work

The Contractor shall nominate representative(s) to be in charge and to co-ordinate the work withthe Project Manager Representative at site. The representative(s) shall remain at site at all timesto supervise the scope of work awarded to them.

Every Contractor employing 40 persons or more shall set-up his own Safety and HealthCommittee and officially appoints one or more qualified safety officers. The officer shall sit in a

joint Safety and Health committee set-up by the Employer or his Project Manager. The functionsof such committee are:






To advise the Contractor on his legal duties

To enforce the implementation of the safety & health requirements

To promote safe work practices

To investigate accident cases and recommend preventive measuresIn the event where the Contractor employs less than 40 employees, the Project Managerreserves the right to request the Contractor the following:

To appoint a safety officer

To set-up own Safety and Health Committee

To jointly set-up a Safety and Health Committee with the Project Manager

To attend the Project Manager ’s Safety and Health Committee meeting

Regular site meetings shall be conducted at a frequency to be determined by the ProjectManager. The following site meeting shall be conducted on regular basis:

Work progress meeting with safety issues to be discussed as the first agenda

Daily reporting on safety issues to the Project Managers safety officer (for majorprojects)

Contractor’s Safety & Health committee meeting weekly

Joint Safety & Health committee meeting every 2 weeks

The Contractor shall immediately inform in writing the following incidents to the Project ManagersSupervising Officer:

Dangerous Occurrences

Accidents

Fire

Occupational Diseases

The Contractor shall be responsible to notify such incident to the relevant authorities such asKPLC, the Department of Occupational Safety and Health (DOSH), Police, the Fire Department,the Department of Environment (DOE), the Labour Department, the Social Security Department,etc.

A detailed written report shall be submitted to the Project Manager within 24 hours after theincident.

In the case of any fatal accident, major fire or disaster, the Contractor shall immediately act perEmergency Response Plan established by the station/site office.

Regular auditing of Contractor’s and Sub -Contractor’s Safety Management Programmes shall becarried out jointly with the Project Managers safety representative. The Contractor shall be awareof the Safety Excellence Management System (SEMS) used by TNB in managing and auditingsafety.

20.3 Security Measures

All workers and vehicles of the Contractor’s shall be subjected to have a fully security checks by

security personnel during entry, while within the premises and on leaving the premises. All personnel shall have valid security passes to be issued by the Project Manager at all time andto produce them upon request. The passes shall be surrendered to the Project Manager at theend of employment or else the Contractor will be penalised.






The Contractor shall observe the station’s se curity requirements at all times.

For the purpose of the issuing passes, the Contractor shall submit the following particulars for allworkers under his employment (including Sub-Contractors) in advance, prior to workcommencement:

Full name

National Registration Certificate numbers (for citizen), and valid passport numbers andvalid work permit numbers (for non-citizen)

Date of birth

Current residential address and contact phone number (if available)

Profession

All vehicle drivers shall drive carefully while within the station/site compound and shall abide bythe speed limit set by the site office. Vehicles shall only be allowed to enter the compound fordelivery of equipment/materials and they shall not be parked in construction compound unlessauthorised by the Project Manager. All vehicles used for construction work shall be in safe andgood working condition.

The Contractor shall ensure proper hoarding and fencing erected before the commencement ofsite work. Adequate perimeter lighting for patrolling purposes shall be provided by the Contractor.

The Contractor shall declare a list of tools/equipment/materials to be brought to site. Only thesedeclared items shall be taken out of site later. The tools/equipment/materials approved by theProject Manager ’s authorised personnel shall undergo security check prior to entry and beforeleaving the site.

The Contractor shall be responsible of his own equipment. The Employer/Project Manager shallnot be liable for any loss or damage to the Contractor’s equipme nt inside the site premise.

All materials, machinery, or tools, etc. belonging to The Employer/Project Manager shall bedeclared to the Site Manager before being taken out of the station premises.

The Contractor shall not operate or tamper with any equipment or apparatus belonging to thestation without prior consent.

20.4 Housekeeping

Storage area shall be kept clean and tidy. The Contractor shall bear all costs with regard tounloading and storage facilities.

The Contractor shall be responsible for the security and safety of equipment and materials storedat site.

The Contractor shall also provide and maintain clean and hygienic washroom facilities, includingmobile toilet if necessary, if the duration of Contract is more than 3 months or the staff is morethan 15 people. If the station/site provides washroom facilities, the Contractor shall contribute tothe repair and maintenance of the facilities.

Sufficient clean / drinking water supply shall be provided by the Contractor at site.

No food or drinks shall be consumed in plant area. The Contractor shall make his ownarrangement in catering the needs of his employees. Alcoholic drinks and dangerous drugs arenot permitted in the construction premises. Such act will constitute an offence and liable toprosecution.

Site canteen may be installed by the Contractor with prior permission from the Project Manager.The Contractor shall ensure that his workers are reasonably clean when entering the station/sitecanteen. Proper canteen shall be provided if necessary, based on the project period.






The Contractor shall provide sufficient First Aid facilities or a clinic for his employees including atleast one trained first aid personnel.

20.5 Permit to Work (PTW)Work involving the extension and modification of existing services will involve working adjacent tolive apparatus. The Contractor shall use personnel adequately competent to work on and/oradjacent to live apparatus.

All such work shall work shall be executed in conjunction with the relevant control centre whoshall always issue a Permit to Work (PTW) before work can proceed. The Contractor shallnominate a competent person for the purposes of obtaining the PTW with respect to theconstruction site.

The request for such PTW shall be jointly made with the Project Manager ’s SupervisingEngineer, to the Shift Charge Engineer on duty. Adequate notice for shall be given to the relevant

control centre in advance. The nominated competent person shall hold a valid Permit to Work at all time for the duration ofthe work, and shall be able to produce it whenever requested by the Project Manager.

20.6 Electrical Safety

The Contractor shall make himself thoroughly conversant with the Electricity Supply Act,Electricity Regulations, and KPLC Electrical Safety Rules governing any work they may have toundertake in any electrical installation or system. All work shall be carried out by competentpersonnel only.

All electrical works and equipment shall conform to JBE Safety Regulations and IEE WiringRegulations Edition 16.

In the case of temporary electrical facilities, the Project Manager may demand for additionalprecautions by the Contractor in order to prevent accidents. Site / station personnel may conductspot checks on temporary electrical facilities; any dangerous items found may be confiscated.

The Contractor shall inform site office/station in advance of any site power supply requirements.The Contractor shall not take supply from any outlet without prior approval from the ProjectManager. For work in confined space, power supply for inspection lamps and lighting shall be 24volts and below. All electrical faults shall be reported immediately to the Project Manager or hisrepresentatives.

Approved non-conductive ladder shall be used for electrical work.

20.7 Fire Prevention

The Contractor and all his employees shall take all reasonable precautions during and afternormal working hours to prevent the outbreak of fire. The Contractor shall provide adequate firefighting equipment in his office, site storage, and work areas.

In the event of an outbreak of fire, the Contractor and all his employees shall assist in fighting thefire. The Contractor shall acquaint all his employees together with any Sub-Contractor with thisrequirement.

Paints and thinner shall be issued in small quantities at site. Such materials shall be removedand kept under proper storage after the day’s work.

Flammable gas cylinder shall be secured and chained in upright position.






Hot Work Permit shall be obtained before starting any work, which involves the use of localignition source capable of igniting flammable combustible materials.

Smoking is strictly prohibited in designated areas.

Where flammable and combustible liquids, vapours, chemical, gases and the like are stored orhandled, personnel shall be prohibited from carrying matches, lighters, and other spark-producing devices.

20.8 Personal Protective Equipment (PPE)

The Contractor shall supply appropriated PPE to his workers at site, as well as to visitors. TheContractor shall ensure that his employees wear them at all times. The purpose is to reduce anyrisks to their safety and health.

Designated areas with instructions such as Wear Hard Hat, Wear Safety Shoes, Wear Ear Muff,No Smoking, No Flame etc. shall be strictly followed.

All equipment shall be in good and safe working condition and meet KPLC safety standards. Theequipment shall be inspected and approved by the Project Manager ’s authorised staff beforeuse.

Workers without PPE and not wearing proper attire shall be barred from entering the station/siteand ordered to leave at once.

20.9 Noise Control

The Contractor shall comply with the Factories and Machinery Act and other Regulationsregarding Noise Exposure.

Employees working in an environment exposed to a noise level equivalent to or exceeding 85 dB(A) shall wear approved hearing protection.

20.10 Signage, Notifications, and Barriers

Symbolic safety signs shall be used to ensure that the requirement for safety signs and noticesare met e.g. notices or labelling of hazardous substances, PPE, traffic sign, life conductors, etc.

Where involves activity near live apparatus, proper non-conductive barrier shall be used toseparate the live area from the construction area.

20.11 Contractor ’s Equipment and Lifting Gears

All equipment and lifting gears which are covered by the provision under Electricity Supply Act1990 and the Factories and Machinery Act 1967 shall have valid Certificate of Fitness issued bythe Department of Occupational Safety and Health (DOSH).

All equipment brought to site shall be in safe and good working condition. The Project Managerreserves the right to inspect and reject them if found unsafe.

Lifting equipment shall never be overloaded. Lifting equipment shall be marked with a SafeWorking Load (SWL) which shall not be exceeded, except for obligatory Overload Test as

prescribed by the DOSH Regulations.






20.12 Area of Work

The Contractor and the Project Manager shall jointly agree and gazette all working areas.

The Contractor shall be responsible for the safety within their working area. Before thecommencement of work, approved barriers and safety signboards shall be erected andprominently displayed.

Horseplay, loitering, and straying from assigned place of work are prohibited. Adequate lightingand ventilation shall be provided whenever required.

The Contractor’s workers shall not encroach outside the gazette area without prior writtenpermission from the Project Manager.

20.13 Confined Space Entry

The Contractor shall obtain a special permit from the Project Manager for work in confined

spaces such as vessels, boilers, condensers, culverts, flue, sewers, tunnels, and undergroundchambers. The Contractor shall identify and test for the presence of hazardous gases beforeallowing his workers to enter any confined space.

Persons entering a confined space shall wear a safety harness with a rope securely fastened,and a person who can pull him out during an emergency shall hold the free end of the rope.

Effective steps shall be taken to prevent the risk of flooding. Means of escape hall shall beprovided for all persons likely to be endangered in the event of flooding.

Forced ventilation shall be provided if natural ventilation is inadequate.

20.14 Working at HeightScaffoldings shall be of approved type and be erected to safety requirements. Workmen shallnot work on scaffolding installed outdoors during storm or high wind.

Gondolas shall have valid Certificate of Fitness issued by the Department of Occupational Safetyand Health (DOSH). Ladders shall be of approved type and in good working condition. Safetybelt/harness shall be worn when working 3 metres or more above ground level.

Safety nets shall be erected to protect workers from falling and also to protect persons belowfrom falling object.

20.15 Working Over/Near WaterWhen working at the jetty, pump house, inside water tanks, etc. special precautions shall betaken to avoid loss of lives due to drowning as a result of falling into water. Working platform shallbe properly constructed and secured.

Barrier or fences shall be erected at all edges where there is a risk of persons falling into water.Personal buoyancy aids shall be worn when there is a risk of drowning, and rescue equipmentshall be readily available as appropriate.

Safety belt shall be worn where necessary.

20.16 Lighting and Ventilation Adequate lighting and ventilation shall be provided at all workplace. Explosion-proof light fittingsshall be used in areas where flammable gas may be present.






a complete knowledge of possible interaction between the two. Any query about the handling ofhazardous materials shall be directed to the relevant station/site Chemists or the Safety Section.

All personnel involved in the handling, transport, storage, or use of hazardous materials shall befamiliar with appropriate emergency procedure (e.g. fire/explosion, accident, spillage, and

leakage). Written emergency procedures shall not be followed blindly but shall be exercised withcommon sense.

Station / site Safety Officer shall be contacted for advice on methods for bulk disposal ofhazardous materials. Special approval from Local Authorities is normally required.

All hazardous materials used or stored by the Contractor at site shall be accompanied withMaterial Safety Data Sheets (MSDS) with proper labelling.

All storage, disposal, and transportation shall be in accordance to the local Statutory Regulations.

20.21 Material Storage at Site

The Contractor shall bear all costs for unloading and storage of any materials supplied for theworks until taking-over.

The Contractor shall allocate sufficient area for office space and storage of erection equipment.The Contractor shall also provide security and protection for their materials. TheEmployer/Project Manager shall not be responsible for any loss and damage to these items.

The Contractor shall ensure that highly flammable substances, paints, etc. are under proper andsafe storage.

The Contractor shall ensure that the ground condition is suitable for heavy/bulk material storage.Storage area shall be fenced and guarded.

The Contractor shall also ensure proper documentation on flow of materials is available at alltime.

20.22 Environmental Obligation

The Contractor shall take reasonable action to ensure that all works and services conform toKPLC policy and all relevant Environmental legislation with regard but not limited to thefollowings:

20.22.1 MSDS (Material Safety Data Sheet):

Station/site Chemist or Safety Officer shall be informed of all chemicals used by providingrelevant MSDS. Chemicals which contain Ozone Depleting Substances shall not be used withoutprior approval from the Project Manager.

20.22.2 PPE (Personal Protective Equipment):

All contractors involve in handling hazardous chemicals shall wear sufficient and suitable PPE.

20.22.3 Disposal and Spillage:

The Contractor shall inform the Project Manager before disposing any chemical, oil, or hazardousmaterial. Oil shall be stored properly in approved areas. Any leak of oil shall be informedimmediately to the Project Manager ’s site supervisor. Contractor shall be liable to carry out allclean-up works in the case of any oil or chemical spillage.

Special method and approval from Local Authorities are normally required as well as complianceto relevant DOE and DOSH regulations. Disposal of waste or oil down the drains or into waterways prior to proper treatment is illegal and prohibited.






20.22.4 Removal of Trees and Ground Vegetation:

During the course of work, the Contractor shall not remove or damage any tree or vegetation inthe surrounding area without prior approval from the Project Manager. If the work involvedrequires the removal of ground cover, the Contractor shall ensure that all steps are taken to

minimise/eliminate soil erosion. Slopes with exposed soil which is susceptible to erosion shall becovered with plastic sheets.

Provision shall be taken to ensure that any sediment washed away from exposed areas shall notenter the station’s drains.

20.22.5 Activity Which Emit Dust Particles:

Creation of dust shall be avoided and where there is any possibility of creating dust, appropriatecontrol measures shall be taken, such as ensure that the tyres of all vehicles leaving or enteringthe site are cleaned of any soil.

Wet the roads which are dusty to prevent dust from becoming airborne due to passing vehicle.

Should the work to be undertaken involve the emission of high noise levels, the Contractor is toget the approval of the Station Management/Site Manager as to the time and duration that this‘noisy’ work can be carried out.

20.23 Waste and Scrap Management

Scraps refer to plants, part of plants, equipment, piping, cables etc., disassembled or demolishedparts which are not to be reassembled or reinstalled.

The Project Manager will allocate suitable area for storage of scrap and waste materials. TheContractor shall be responsible for the removal and proper storage of all scrap and waste

materials resulting from their works. All accumulated waste materials resulting from the works shall be disposed regularly. At no timeshall any waste material be disposed by burning. Any oil or other harmful waste shall not beallowed to discharge into the drain.

On completion of work, the site shall be left clean and tidy to the satisfaction of the StationManager. The Contractor is responsible for the removal of the accumulated debris from his worksite to the dumping ground approved by the Local Authorities.

The Contractor shall seek approval from DOE when disposing toxic waste.

20.24 EmploymentThe Contractor shall be responsible for arranging whatever documents deemed necessary forthe entry and residence of employees that may be required to be brought to the Employer’scountry for the purpose of the Contract. The Contractor shall be responsible for ensuring that allhis employees comply with all Labour laws of Kenya.

The Contractor is to fulfil all his obligations in respect to site office accommodation, medicalfacilities for all personnel in his employ, in accordance to the responsibility imposed on him, or allnecessary requirements to ensure satisfactory execution of the Contract. He shall also complywith the requirements of The Employment Act and all other Statutory Regulations.

The Contractor shall be responsible for the discipline and safety on site of all personnel

employed by him.






20.25 Emergency Response Plan (ERP)

The Contractor shall consult the Project Manager on relevant portion of ERP for the station. TheContractor shall prepare and submit the ERP to the Project Manager.

In an emergency e.g. fire or explosion, immediate evacuation is necessary. Any accident at worksite shall be reported immediately to the Contractor’s supervisor and station engineer.




Chapter 21: Testing and Commissioning


Contents

21

TESTING AND COMMISSIONING ........................................................ 1

21.1 General .......................................................................................................... 1

21.1.1 Commissioning programme ........................................................................... 1

21.1.2 Pre-commissioning Tests ............................................................................... 1


21.2 Testing and Commissioning for Breakers ................................................. 1

21.2.1 Site Tests ......................................................................................................... 2

21.2.2 Testing and Commissioning ........................................................................... 2

21.3 Testing and Commissioning for Isolators ............ .............. ............ ............ 2 21.4 Testing and Commissioning for Current Transformers ............ ............. ... 3

21.5 Testing and Commissioning for Voltage Transformers ............ ............. ... 4

21.6 Testing and Commissioning for Surge Arresters ............. ............. ............ 4

21.7 Commissioning Tests for Kiosk and Terminal Boxes ............. ............. ..... 5

21.7.1 Conductors, Insulators, Accessories ......... .......... ......... ......... ......... .......... ..... 5


21.8 Commissioning Tests for Battery Installation..................... ............. .......... 6

21.9 Commissioning Tests for Battery Charger .............. ............. ............ .......... 6

21.10 Commissioning Tests for Relays and Protection Schemes .............. ....... 7

21.10.1 General ............................................................................................................. 7

21.10.2 Commissioning and Routine Testing Facilities for Relays ......... .......... ........ 7

21.10.3 Test of Wiring .................................................................................................. 7

21.10.4 Test of Relays .................................................................................................. 8

21.10.5 Test of D.C. Circuits .......... ......... ......... .......... ......... .......... ......... ......... ......... .... 8

21.10.6 Test of Instruments ......... ......... .......... ......... .......... ......... ......... ......... .......... ..... 8


21.10.8 On Load Test ................................................................................................... 8

21.10.9 Relay Settings .................................................................................................. 9

21.11 Site Tests for Transformer ............. ............. ............. ............. ............. .......... 9






21 TESTING AND COMMISSIONING

21.1 General

21.1.1 Commissioning programme

The commissioning schedule shall be submitted to the Employer and Project Manager two (2)months prior to start of commissioning for approval. This is a hold point. The commissioningprogramme shall include but not limited to:

i) List of all the site tests to be done for all protection, telecommunication and associatedswitchgears and auxiliary equipment.

ii) Procedures and methods for each commissioning tests including those to beperformed on – load

iii) Testing equipment and instruments necessary for performing each test

iv) Formats of site tests reports for each test

v) Installation, operation and maintenance manuals

21.1.2 Pre-commissioning Tests

Before energising equipment, each item shall be thoroughly cleaned and inspected forcorrectness and completeness of installation and acceptability for livening, leading to initial pre-commissioning tests at Site. An indicative of list of pre-commissioning tests to be performed isgiven below.

All electrical equipment and installations shall be tested for correct connections of the high-voltagecircuits as well as of the control and measuring circuits, installation, insulation, and earthing.

All electrical equipment and installations shall be subjected to a complete operational test to checkthe correct operation thereof in terms of the operational requirements specified in theseSpecifications.

The tests described below shall be used as a guideline and may be changed or varied after writtenapproval from the Project Manager due to changes in design, manufacturing or constructiontechniques.

21.1.3 Commissioning Tests

The available instrumentation and control equipment will be used during such tests and all suchmeasuring equipment and devices as far as practicable need to be calibrated. However,immeasurable parameters shall be taken into account in a reasonable manner (that will be agreed

upon by the Project Manager) for the requirement of these tests. The tests will be conducted atthe specified load points and as near the specified cycle condition as practicable. The propercorrections in calculation to take into account conditions which do not correspond to the specifiedconditions can be applied.

The Contractor shall perform any additional test based on specialties of the items as per the fieldQ.P. and/or instructions of the equipment Supplier. The Contractor will be required to provide allinstruments needed for conducting these tests. He shall also be required to furnish the list ofinstruments to be used to the Project Manager ’s for approval, along with calibration certificates forthe same equipment.

IEC60060-2 may be used as guidelines in test requirements.

21.2 Testing and Commissioning for Breakers

Routine tests as per IEC-62271-100 shall be performed on all circuit breakers. In addition to the






mechanical and electrical tests specified by IEC, the following tests shall also be performed.

Speed curves for each breaker shall be obtained with the help of a suitable operation analyser todetermine the breaker contact movement during opening, closing, auto-reclosing and trip freeoperation under normal as well as limiting operating conditions (control voltage, pneumatic /hydraulic pressure etc.). The tests shall show the speed of contacts directly at various stages ofoperation, travel of contacts, opening time, closing time, shortest time between separation and

meeting of contacts at break make operation etc. This test shall also be performed at site forwhich the necessary operation analyser along with necessary transducers, cables, console, etc.where included in scope of supply shall be furnished and utilised. In case of substations whereoperation analyser exists the Contractor shall utilise the same. However necessary adopter andtransducers etc. if required shall have to be supplied by the Contractor.

Measurement of dynamic contact resistance for arcing and main contacts shall be taken asreference for comparing the same during operation and maintenance in order to ascertain thehealthiness of contacts.

21.2.1 Site Tests

All routine tests on main circuit breaker shall be repeated on the completely assembled breaker at

site.

21.2.2 Testing and Commissioning

An indicative list of tests is given below. The Contractor shall perform any additional test basedon specialties of the items as per the field Q.P./instructions of the equipment Supplier or theProject Manager to IEC criteria without any extra cost.

The Contractor shall arrange all instruments required for conducting these tests along withcalibration certificates. Where any of these tests were reasonably carried out at the factory, TestCertificates shall be provided to the Project Manager.

a) Insulation resistance of each pole.

b) Check adjustments, if any suggested by manufacturer.c) Breaker closing and opening time.

d) Slow and Power closing operation and opening.

e) Trip free and anti-pumping operation.

f) Minimum pick up voltage of coils.

g) Dynamic Contact resistance measurement.

h) Functional checking of compressed air plant and all accessories.

i) Functional checking of control circuits interlocks, tripping through protective relays and

auto reclose operation. j) Insulation resistance of control circuits, motor etc.

k) Resistance of closing and tripping coils.

l) SF 6 gas leakage check.

m) Dew Point Measurement

n) Calibration of pressure switches and gas density monitor.

o) Checking of mechanical 'CLOSE' interlock, wherever applicable.

21.3 Testing and Commissioning for IsolatorsIt shall assumed that the isolator along with its earthing switch and operating mechanism shouldhave been type tested as per IEC Standard and should have been subjected to routine tests in






accordance with IEC 62271-102. Power frequency voltage withstand tests shall have beenperformed on at least one completely assembled isolator pole of each type. Minimum 50 Nos.mechanical operations will have been carried out on 1 (one) isolator out of every ten Isolatorsassembled completely with all accessories as acceptance test for the lot.

An indicative list of tests on isolator and earth switch is given below. The Contractor shall performany additional test based on specialties of the items as per the field Q.P./instructions of the

equipment Supplier without any extra cost. The Contractor shall arrange all instruments requiredfor conducting these tests along with calibration certificates. Where any of these tests werereasonably carried out at the factory, Test Certificates shall be provided to the Project Manager.

The test reports of the above type tests and the following additional type tests to IEC criteria shallbe submitted to the Project Manager for review.

a) Radio interference voltage test

b) Seismic withstand test on isolator mounted on Support structure. The test shall havebeen performed in the following position:

Isolator open E/S Closed

Isolator open E/S Open Isolator Closed E/S Open

All routine tests including 50 operation test, except power frequency dry voltage withstand test onisolator shall be repeated on completely assembled isolator of each type at site.

An indicative list of tests on isolator and earth switch is given below. The Contractor shall performany additional test based on specialities of the items as per the field Q.P./instructions of theequipment Supplier.

a) Insulation resistance of each pole.

b) Manual and electrical operation and interlocks.

c) Insulation resistance of control circuits and motors.d) Ground connections.

e) Contact resistance.

f) Proper alignment so as to minimise to the extreme possible the vibration duringoperation.

g) Measurement of operating Torque for isolator and Earth switch.

h) Resistance of operating and interlocks coils.

i) Functional check of the control schematic and electrical & mechanical interlocks.

21.4 Testing and Commissioning for Current Transformers

The test reports of the type tests and the following additional type tests to IEC 60044-1 criteriashall be submitted to the Project Manager for review.

a) Measurement of Capacitance.

b) High voltage power frequency withstand test on Secondary Winding.

c) Over-voltage inter turn test (as per BS: 3938).

d) Oil leakage test.

e) Measurement of tan delta at 0.3, 0.7, 1.0 and 1.1 Um/_3.

f) Measurement of partial discharge shall be carried out as per IEC.

Dissolved gas analysis needs to be carried out at the time of commissioning.






An indicative list of other tests that need to be carried out on Current Transformers is given below.The Contractor shall perform any additional test based on specialities of the items as per the fieldQ.P./instructions of the equipment Supplier.

a) Insulation Resistance Test for primary and secondary.

b) Polarity test.

c) Ratio identification test - checking of all ratios on all cores by primary injection ofcurrent.


e) Magnetising characteristics test.

f) Tan delta and capacitance measurement.

g) Secondary winding resistance measurement.

21.5 Testing and Commissioning for Voltage Transformers

The test reports of all type tests and the following additional type tests to IEC 60044-2 criteriashall be submitted to the Project Manager for review.

a) Capacitance and loss angle measurement before and after voltage test.

b) Partial discharge test on capacitor dividers.

c) Sealing test.

d) Natural frequency of capacitor unit determination (Resonant frequency of capacitorunits).

An indicative list of other tests that need to be carried out on Current Transformers is given below.The Contractor shall perform any additional test based on specialities of the items as per the field

Q.P./instructions of the equipment Supplier.a) Insulation Resistance test for primary (if applicable) and secondary winding.

b) Polarity test.

c) Ratio test.


e) Tan delta and capacitance measurement between:

HV - HF point;

HF Point - Ground point of Intermediate Transformer;

HV - Ground point of Intermediate Transformer primary winding.f) Secondary winding resistance measurement.

21.6 Testing and Commissioning for Surge Arresters

The test reports of all type tests and the following additional type tests to IEC 60099-4 criteriashall be submitted to the Project Manager for review.

a) Test on Complete Arrester unit:

Radio interference voltage test;

Seismic withstand test; Contamination test;

Measurement of power frequency reference voltage of the arrester units;






Lightning Impulse Residual voltage on arrester units;

Internal Ionisation or partial Discharge test;

Thermal stability test on three sections;

Aging & Energy Capability test on blocks;

Watt loss test:o Measurement of reference voltage;

o Residual voltage test of arrester unit;

o Internal Ionisation test or partial discharge test;

o Sealing test;

o Verticality check on completely assembled Surge arresters as a sample teston each lot.

b) Test on Surge Monitors

The Surge monitors shall also be connected in series with the test specimens duringresidual voltage and current Impulse withstand tests to verify efficacy of the same.

Additional routine/ functional tests with one 100A and 10kA current impulse, (8/20micro sec.) shall also be performed on the Surge monitor.

c) Test on insulators

All routine tests shall be conducted on the hollow column insulators as per IEC 60233[this is superseded, so equivalent shall be nominated]. The following additional testsshall be carried out on insulators:

Ultrasonic test as a routine test;

Pressure test as a routine test;

Bending load test in 4 directions at 50% specified bending load as a routine test; Bending load test in 4 directions at 100% specified bending load as a sample

test on each lot;

Burst pressure test as a sample test on each lot.

d) Testing And Commissioning

An indicative list for the test of surge arresters is given below. The Contractor shallperform any additional test based on specialities of the items as per the fieldQ.P./instructions of the equipment Supplier.

Leakage current measurement.

Resistance of ground connection.

21.7 Commissioning Tests for Kiosk and Terminal Boxes

Tests shall be made in accordance with the applicable IEC or equivalent Standard.

21.7.1 Conductors, Insulators, Accessories

Tests for physical and electrical properties on conductors shall be made in accordance with ASTMStandard B 398 and 399 or other equivalent and approved standard. These tests on wires shallbe made on wires removed from the complete conductor. All wires making up the conductor

sample shall be tested.

21.7.2 Tests on the Switchyard on Site Error! Bookmark not defined.

All electrical equipment and installations shall be tested for correct connections of the high-voltage






circuits as well as of the control and measuring circuits, installation, insulation, and earthing.

All electrical equipment and installations shall be subjected to a complete operational test tocheck the correct operation thereof in terms of the operational requirements specified in theseSpecifications.

21.8 Commissioning Tests for Battery InstallationBatteries shall conform to all type tests as per the latest issue of the relevant InternationalStandard and all Acceptance tests as required by the relevant Standards shall be carried out atsite after completion of installation. The capacity tests shall be carried out for 10 hr. dischargerating. The Contractor shall arrange for all necessary equipment, including the variable resistor,tools, tackles and instruments. If a Battery fails to meet the guaranteed requirements theEmployer/Project Manager shall have the option of asking the Contractor to replace the same withan appropriate battery without affecting the commissioning schedule of the Project.

Two (2) copies of Type test certificates for the following tests shall be provided to the ProjectManager for review:

a) Capacity testsb) Watt hour and AH efficiency tests

21.9 Commissioning Tests for Battery Charger

Test certificates for the following tests shall be provided for review by the Project Manager:

a) Voltage regulation test

b) Load limiter characteristics test

c) Efficiency tests

d) High voltage tests

e) Temperature rise test

f) Short circuit test at no load and full load at rated voltage for sustained short-circuit.

g) Degree of protection test

h) Measurement of ripple by oscilloscope.

At site the following tests shall be carried out:

a) Insulation resistance test

b) Checking of proper annunciation system operation.

c) Capacity tests

If a Charger fails to meet the require specification, the Contractor shall replace the same withappropriate Charger without affecting the commissioning schedule of the Project.

The Contractor shall present for inspection, the type and routine test certificates for the followingcomponents if required by the Project Manager:

a) Switches.

b) Relays/MCCBs

c) Instruments.

d) DC fuses.e) SCR.

f) Diodes.






g) Condensers.

h) Potentiometers.

i) Semiconductor

j) Annunciator.

k) Control wiring

l) Push buttons for contactors.

m) Makes of above equipment shall be subject to Project Manager ’s approval.

21.10 Commissioning Tests for Relays and Protection Schemes

21.10.1 General

Tests as described below shall be used as a guideline and may be changed or varied withagreement from the Employer/Project Manager, due to changes of design manufacturing ofconstruction techniques.

21.10.2 Commissioning and Routine Testing Facilities for Relays

Each functional relay scheme shall be so arranged that operation and calibration checks can becarried out when the associated primary circuit(s) is (are) in service and form part of theoperational network. Adequate test facilities shall be provided at the front of the relay panel toenable the protective equipment and auto-reclosing equipment to be tested whilst the primarycircuit is on load, without having to disturb any wiring.

Adequate facilities shall be provided at the front of each relay panel to isolate all d.c. and a.c.incoming and outgoing circuits so that work may be carried out on the equipment with completesafety to personnel and without loss of security in the operation of the plant. The Contractor shall

list all test equipment required for commissioning and routine testing of the installed protectionequipment.

Where test equipment is specified, it shall include such injection transformers, test leads andplugs as are necessary to carry out secondary injection tests on each type of relay scheme and,for the more complex schemes, such special test equipment as may be necessary to verify theaccuracy of timing and verify the effective operating characteristics of the equipment.

For solid state measuring equipment the Contractor shall list such test as may be required to carryout on-site investigations into the performance of individual modules or printed circuit cards. Atleast one complete set of any special test equipment shall be supplied with this project togetherwith such additional connections, dummy extension boards, etc., as may be necessary.

21.10.3 Test of WiringInsulation Resistance Test at 1000 Volts a.c. for one minute shall if possible be carried out on alla.c and d.c. protection, control, alarm and indication circuit to ensure that wiring is in satisfactorycondition. Ocular inspection shall be made on cable glands, cable jointing, fuse or circuit breakerratings and small panel items, such as indicating lamps.

Static equipment which may be damaged by the application of test voltages shall have theappropriate terminals disconnected.

Inter-relay, inter-unit and cubicle wiring carried out at site is to be checked to the appropriatecircuit and/or wiring diagram. This may be done by using bells or buzzers. D.C. supplied from thestation battery may also be used. Where it is found necessary during commissioning work toeffect site modification to the secondary wiring, site copies of the appropriate schematic andwiring diagrams shall be suitably marked and a set of as-built drawings indicating the changesproduced.

Loop resistance measurements are to be done and on all current transformer circuits. Separate






values are required for current transformer and lead resistances and all measurements are to berecorded on lead resistance diagrams.

21.10.4 Test of Relays

All relays are to be examined to ensure that they are in proper working conditions and correctlyadjusted, correctly labelled and that the relay case, cover, glass and gaskets are in good order.

Secondary injection shall be carried out on all a.c. relays, using voltage and current of sinusoidalwaveform and rated power frequency. For circulating current protection employing highimpedance voltage setting test shall be across the relay and stabilising resistance. The operationsetting for the type of protection is to be established by secondary injection, where it is notpossible to ascertain this value.

The tests on site shall include but not limited to:

Individual relay calibration and Functional tests Residual voltage (current) measurement Measurement of burden Current and voltage transformer circuits grounding point check

Sequential operation test at each station by primary and secondary injection tocheck sensitivity and stability Station to station operation performance tests (transmission line protective

relaying equipment only). Test on Trip and alarm circuits Stability, Operation, and Sensitivity of transformer unit schemes Test of Autoreclose schemes Calibration Tests on all Instruments Calibration Test on Energy meter

21.10.5 Test of D.C. Circuits

Tests are to be carried out to prove the correctness of all d.c. polarities, the operating levels ofd.c. relays and the correct functioning of d.c. relay schemes, selection and control switching,indications and alarms.

21.10.6 Test of Instruments

Instruments and instrument transformer circuits shall be checked for polarity of direction and forcalibration including any interposing transformers or transducers. These checks shall be made onall current transformer ratios where applicable.

21.10.7 Tests on the Switchyard on Site

All electrical equipment and installations shall be tested for correct connections of the high-voltage

circuits and shall be subjected to a complete operation test to check the correct operation thereofin terms of the operational requirements of the specific equipment.

The resistance to earth of the earthing system of the switchyard shall be measured. The earthingsystems shall be checked for conductivity and reliable connections.

21.10.8 On Load Test

On load tests are required, but due to the hazards inherent they shall be carried out under thedirect supervision of the Employer’s Staff. The following tests are required:

An operation and stability test shall be carried out for on-load commissioning.

Test for restraint shall be carried out to prove the characteristic of protective andmeasuring systems with directional characteristics.

Test for stability and restraint shall be carried out to prove the characteristic of protectiveand measuring systems with unit protection such as differential protection scheme.






On-load checks shall be made after the protective gear has been placed in service toensure that all connections and test links have been replaced and test leads removed, aswell as to confirm the integrity of the current transformer circuits. Where necessary,voltage readings shall be taken at the terminals on each relay to ensure that loopconnections between the relays are complete. Special attention shall be paid to brokendelta voltages and residual current circuits were zero voltage or current respectively maynot be proof of the completeness of the circuit.

21.10.9 Relay Settings

The protection setting philosophy and policy as well as the system parameters required shall beprovided by the Employer. The contractor shall then submit settings calculations of the stationsetting two (2) months before start of commissioning period for approval by the Projectmanager/ Employer . The relay settings shall be applied to the equipment by the Contractor, priorto making all commissioning tests.

21.11 Site Tests for Transformer

Testing at site by the Contractor (or his Representative) shall be carried out to prove that the

transformer in all respects complies with the specification as provided to the Contractor by theEmployer.

Tests shall include but not be limited to the following:

All Routine tests

Dielectric oil tests.

Insulation dryness by an agreed method.

Electrical and functional control of voltage control equipment and cooling system.

Core to tank insulation.

Measurement of Bushing tan delta at 0.3, 0.7, 1.0 and 1.1 of Phase to Neutral




22. EARTHING




Chapter 22: Earth (Ground) System


Contents

22 EARTH (GROUND) SYSTEM ............................................................. 1 22.1 General .......................................................................................................... 1




22.5 Detailed Specification ............ ............. ............ .............. ............. ............ ....... 2

22.5.1 General ............................................................................................................. 2

22.5.2 Earth Electrode System under the Control Building ......... ......... .......... ......... 2

22.5.3 Earth Electrode System of the Switchyard ......... ......... ......... ......... .......... ...... 3

22.5.4 Earth Conductors ............................................................................................ 3

22.5.5 Construction of Earth Grids ......... .......... ......... ......... ......... .......... ......... ......... .. 4

22.5.6 Earth Points ..................................................................................................... 4

22.5.7 Connection of Earth Points and System Neutrals .......... ......... ......... .......... ... 4

22.5.8 Equipment Earths .......... ......... .......... ......... ......... ......... ......... .......... ......... ........ 5

22.5.9 Jointing and Bonding ...................................................................................... 5






22 EARTH (GROUND) SYSTEM

22.1 General

This chapter covers technical requirements of the earth electrode systems and the earthconductors for the connection of metallic parts, of lightning arresters and of the system neutrals,designed to protect persons and material and to allow for the correct service, operation andmaintenance of the installations.

The work under this section shall comprise the design and calculations, supply, installation andmeasuring of earth systems and connection to all electrical apparatus supplied under thiscontract. Also included is the provision of portable earthing devices.

The earth system shall consist of the earth electrode system in the ground under the switchyard,and of the earth conductors above ground and in the buildings.

The Contractor shall design the complete earth system, and shall measure and verify the specificearth resistance at all places where earth electrodes will possibly be buried, provide drawings ofthe earth electrode grids, calculate the resulting earth electrode resistance, and supply all

information about the planned earth electrode systems.The Contractor will be required to prepare installation drawings and schedules of material to beprovided such as the earth conductors above ground and in the buildings, and make thenecessary calculations for the dimensioning of the earthing conductor systems. All the abovedrawings and schedules shall be submitted to the Project Manager for approval together withcalculations of step, touch and mesh potentials as well as grid potential rise.



For preliminary design purposes the earth resistivity shall be taken as 500 ohm-metres, butduring detailed design earth resistivity tests shall be conducted and final design based on thesecalculations without variation to price.



It is jointly the Contractors and manufacturer’s responsibility to be familiar with any other climatic

and physical conditions pertaining to the specific sites as defined in Chapters 1-3 and to allowfor all conditions in designs.


All equipment shall be designed, constructed and tested in accordance with requirements of thelatest version of standards herein except to the extent explicitly modified in this Chapter.

The earthing for all equipment and the provision of earth systems, electrodes and connectionshall be in accordance with the r ecommendations in the “Guide for safety in substat iongrounding” ANSI/IEEE No. 80– 1986 and the requirements of British Standards BS 6651 and BS7430.








22.5.1 General

New sites shall be provided with an earth grid of buried conductors designed for an earth fault

current as specified in Sub-chapter 3.6.2. The preliminary design shall be such that the potentialrise shall not exceed 5kV.

The earth system shall be constructed and installed to comply with the requirements of localregulations and of the applicable Standards.

More specifically and independent of (or in addition to) the regulations and standards, theearthing system shall provide:

a) Adequate protection for personnel against dangerous voltages, currents and arcs;

b) Safe touch voltages and step voltages. The Step and touch voltages both inside andoutside the station shall not exceed 313V and 885V respectively assuming a crushedstone surface with a resistivity of 3000 ohm-meters, and a maximum exposure time of

0.5 seconds;c) A low earthing impedance for the lightning arresters;

d) Earth points shall be provided such that the combined resistance of the earth grid andall other earth points do not exceed one (1) ohm under any climatic conditions;

e) A low earth impedance for the transformer neutrals and a sufficiently low neutralconductor impedance;

f) Limitation of the induced, or capacitively transformed, voltages on low voltage,current and electronic cables, circuits, panels and other equipment;

g) That short circuit, earth fault and double earth faults currents will flow through theearth systems and not through other conducting parts or building constructions to ahazardous extent.

The maximum resistance of the earth electrode grid in the switchyard and under the controlbuilding shall be 0.5 ohm during the dry period. In addition, the earth electrode system as well asall other earth systems shall be designed and constructed for the operating voltages, the designshort circuit capacities and the corresponding short circuit and earth fault currents specified inSub-chapter 3.6.2 for the respective voltage systems.

The dimensioning shall be co-ordinated with the relay protection scheme of the various parts ofthe plant. In any case, however, the earth conductors shall be dimensioned for carrying the earthfault current and double earth fault currents of the various parts of the plant for at least 1 (one)second without any harm to the conductors or connections.

The conductors shall be reliably protected against mechanical damage and corrosion.

Buried connection shall be made by compression clamps or by approved exothermic weldingprocess. No bolted clamps may be used underground except where accessible by link chamber(covered inspection/test pit). Connections above ground shall be bolted and shall be easilyaccessible for test purposes. All connections shall be protected against corrosion.

The Contractor shall submit his preliminary design for the earth systems for approval by theProject Manager. This shall include measurement of soil resistivity, calculations of resistance,potentials and current ratings for current flowing into or out of the ground and physical design ofthe system.

22.5.2 Earth Electrode System under the Control Building

The conductors shall be of electrolytic copper with dimensions at least 30 x 3 mm for flat bar or atleast 95mm 2 stranded wires. Copper-weld of approximately the same conductivity may be used.






Risers shall be copper stranded wire at least 95mm 2.

The conductors shall be placed on the ground after the excavation is completed and just beforethe concreting starts. Care must be taken that the earth wire is in good contact with the soil andpreferably embedded into it.

Under the building the grid of conductors shall be placed with an average distance between

conductors of not more than 10 m. At all crossings the conductors shall be interconnected byexothermic welding. The grid shall also be connected to the concrete reinforcement at severalplaces as well as to the earthing grid of the switchyard area. Vertical risers shall beexothermically welded to the conductors where not accessible for inspection/testing.

The risers shall be placed in the concrete shuttering, and led out of the shuttering at appropriateplaces approximately 30 cm above the floors. Care shall be taken to protect the risers againstdamage during shuttering and concreting.

Connecting terminals for the screwed connections between the risers and the above-floor mainearthing conductors shall be placed at easily accessible places and protected against mechanicaldamage.

The above information describes the minimum requirements. The final design and constructionfor the achievement of the total requirements of the earthing systems shall be made by theBidder.

22.5.3 Earth Electrode System of the Switchyard

The conductors shall be of electrolytic copper with dimensions at least 30 x 3 mm for the flat baror at least 95 mm 2 stranded wire. Copper-weld with approximately the same conductivity may beused.

The risers shall be of at least 95 mm 2 stranded copper wire or equivalent copper-weld.

The conductors shall be placed forming a grid covering the whole switchyard area. The averagedistance between the conductors shall not be more than 10 m.

Earth mats connected to the main earthing grid shall be installed at the position of operatingcubicles/handles of 132 kV isolating switches in the 132/33 kV substations.

A conductor shall also be placed outside the fence along the whole length of the fence at adistance and at a depth suitable for the potential gradation needed to avoid dangerous touchvoltage between the fence and the ground.

Trenches for the earthing grid shall be excavated in the ground to reach soil of good conductivityand a layer of at least 25 cm of the same material shall be placed over the conductor. Theconductor shall at no place be less than 80 cm below the ground level.

Where advantageous for achieving low resistance to ground, vertical copper-weld earthing rodsmay also be used, in addition to the horizontal grid.

Connecting terminals for the bolted connections between the risers and the above ground earthconductors shall be placed in easily accessible locations for testing and visual inspection.

The above information describes the minimum requirements. The final design and constructionfor the achievement of the total requirements of the earth system shall be made by the Contractorsubmitting to the Project Manager for approval.

22.5.4 Earth Conductors

In the control building a main earthing bus shall be installed on each floor in the cable trenches.

The conductors for these main earthing buses shall be of electrolytic copper with flat bar orstranded conductor.

All the risers from the earth electrode systems shall be connected to these main buses bydisconnecting bolted connections. At appropriate places at the end of the buses they shall beinterconnected, thus to the greatest extent forming interconnected grids or loops.






Branch-offs to switchgear, panels and other parts which shall be earthed shall be of electrolyticcopper with adequate dimensions for each item to be earthed.

Each item shall be directly connected to an earth conductor and not through a series connectionof other metallic parts.

Where rows of switchgear cubicles, boards and panels occur, each cubicle, board or panel shallbe earthed individually.

The fence of the switchyard shall be earthed at distances of not more than 20 m.

Earth conductors for low current and electronic systems shall be insulated and shall be run fromthe systems, panels, etc., directly to a main earthing bus close to a connection to the earthelectrode system. These earth conductors shall not be mixed with the earth conductors of thehigh power systems.

Earth switches and lightning arresters shall have a riser directly connected to the current carryingpart in addition to a riser connected to the structure.

All outdoor earth conductors shall be insulated with spacers or conduits against contact withgalvanised steel structures.

22.5.5 Construction of Earth Grids

The earth grids shall be of high conductivity copper conductor, area not less than 200mm 2,subject to design verification and shall be installed by the Contractor at a 500mm depth. Anyexcavation and back filling necessary will be carried out by the Contractor and installationincluding Employer/Project Manager inspection of the earth grid shall be carried out to suit thecivil works program.

22.5.6 Earth Points

Where the minimum earth resistance may not be achieved by the installation of the earth grid,additional earth rods shall be used as appropriate.

The number of earth points necessary for installation of additional earth rods shall be verified bysite earth resistivity tests after the signing of the contract.

Each earth point shall consist of not less than four and not more than eight 25mm diametercopper rod electrodes, each 3.5 meters and driven or drilled into undisturbed ground at spacingsof not less than the length of the rods. Each electrode shall be complete with approved non-ferrous clamps for the connection of earth conductors and with a hardened steel tip and cap fordriving by means of a power hammer.

Test link chambers and covers for each point shall be provided and a drawing showing theproposed arrangement shall be submitted by the contractor for approval. Locations for theelectrode chambers and the interconnection arrangement shall be approved by the Employerwhen the results of the site earth resistivity tests are known.

22.5.7 Connection of Earth Points and System Neutrals

The electrodes of an earth point shall be arranged in two groups with a conductor from eachgroup to the test link and there shall be duplicate conductors from each test link to the earth grid.Each connection to the earth grid shall be at a link chamber adjacent to the grid with twoconductors from the grid connected to one terminal. Where the electrode groups are close to thegrid the group connection can be made directly to a link chamber at the grid.

Any neutral points for high voltage systems within a substation shall have duplicate connectionsto the closest link chamber(s) of an earthing point(s).

Conductors interconnecting the electrodes to a test link and between the tests links and the earth

grid shall have a cross-sectional area or not less than 95mm2

copper. There shall be at least twosuch connections from each link to the electrodes and to the earth grid. Duplicate connectionmay be in the form of rings.

Earthing conductors shall be of annealed high conductivity copper stranded in accordance with






Table 4 in BS.6346 and protected with an extruded PVC sheath of 1000 volts grade.

Earth conductors shall normally be buried directly in the ground but where necessary they maybe cleated to walls, fixed to cable racks or laid in the cable trenches as convenient.

22.5.8 Equipment Earths

The frames of all electrical apparatus and the bases of all structural steelwork shall be connectedby branches of the same cross section area to the earth grid or to subsidiary branches running toa group of equipment. All disconnector bases, earth terminals and earthing switches, neutralcurrent transformers, power transformers, surge arrester bases and towers and gantries onwhich overhead earth wires are terminated shall be connected to the earth grid.

Surge arresters installed for the protection of transformers shall be connected by direct lowreactance paths both to the transformer tank and the earth grid. Particular care shall be taken toavoid any sharp bends, yet with lengths of such leads otherwise minimised, to avoid additionalhigh impendence at lightning frequency levels.

Capacitor voltage transformers used in connection with line traps shall be connected by direct lowreactance paths to a single earth rod in addition to the earth grid.

Where station fences are in uninsulated metallic material, they shall be connected to the earthgrid at all supporting posts or columns and to 35mm 2 copper conductors buried in 1m outside thefence at a depth of 500mm.

Disconnector and earth switch operating mechanisms and circuit breaker control kiosks notintegral with the circuit breaker shall be connected to the earth system by a branch entirelyseparate from that employed for earthing the Disconnector, earthing-switch or circuit breakerstructure. Such branches shall be connected to a ground mat which shall be provided beneaththe position where an operator will stand.

Galvanized steel structures with sufficient area and current carrying capacity may be used as partof the earth connection to post and strain insulators and to overhead earth conductors which shallbe terminated directly on the steel works.

Buildings containing electrical equipment shall be provided, at each level, with a ring of earthconductors which shall have duplicate connections to the earth grid outside the building. Theframes of all switchgear, control and relay panels and other electrical equipment and exposedstructural metal work shall be connected by branches to a ring. The ring and branch conductorsshall be of the same material as the earth grid.

Strip run within buildings, inside cable trenches or above ground level apparatus shall be neatlysupported in non-ferrous clamps.

22.5.9 Jointing and Bonding

Connections to plant and equipment shall be made using earth terminals to the criteria specified

in this Chapter and Sub-chapter 3.28 . Where a strip has to be drilled to fit an earth terminal thediameter of the hole shall not be greater than a quarter the width of the strip.

Stranded earth conductors shall be terminated with sweated or crimped cable lugs.




23. CIVIL




Chapter 23: Civil Works


Contents

23 CIVIL WORKS ..................................................................................... 1

23.1 General .......................................................................................................... 1

23.1.1 Location of the Works .................................................................................... 1

23.1.2 Type of Works ................................................................................................. 1

23.2 Particulars of Electrical System ..................... ............ ............. .............. ...... 1


23.4 Standards, Units and Language ............ ............. ............. ............. ............. .. 2

23.5 General Requirements ................................................................................. 2

23.5.1

Sequence of construction .............................................................................. 2

23.5.2 Use of Site ....................................................................................................... 2

23.5.3 Plan of Operations and Temporary Works .................................................... 2

23.5.4 Contractor’s Office and Accommodation ...................................................... 2

23.5.5 Site Office for Project Manager and Employer’s Representative ................ 3

23.5.6 Maintenance of Office for Employer’s Representative ................................ 3

23.5.7 Survey Instruments and Chainmen ............................................................... 3

23.5.8 Telephone ........................................................................................................ 3

23.5.9

Dealing with Water .......................................................................................... 3

23.5.10 Liaison with Police and other Officials .......................................................... 3

23.5.11 Explosives and Blasting ................................................................................. 4

23.5.12 Works Executed by the Employer or the Project Manager or byother Contractors ............................................................................................ 4

23.5.13 Water supplies for the works ......................................................................... 4

23.5.14 Water supplies for the Employer or the Project Manager ................. ......... .. 4

23.5.15 Employers approval of finished works .......................................................... 5

23.5.16 Preservation of trees ...................................................................................... 5

23.5.17 Survey beacons .............................................................................................. 5

23.5.18 Basic survey and setting out ......................................................................... 5

23.6 Earthworks .................................................................................................... 5

23.6.1 Bush clearing .................................................................................................. 5

23.6.2 Removal of top soil ......................................................................................... 6

23.6.3 Road bed preparation ..................................................................................... 6

23.6.4 Order of work .................................................................................................. 6

23.6.5 Fill Material ...................................................................................................... 6

23.6.6 Spoil Material .................................................................................................. 6

23.6.7 Expansive Material .......................................................................................... 6






23.6.8 Surplus Material .............................................................................................. 6

23.6.9 Formation, Sub-grade and Pavement ............................................................ 6

23.6.10 Side Drains ...................................................................................................... 7

23.6.11 Excavation in “Rock” ...................................................................................... 7

23.6.12 Setting Out and Preparation for Earthworks ......... ......... ......... ......... .......... ... 7

23.6.13 Construction of earthworks to formation ...................................................... 7

23.6.14 Unsuitable Material Information ..................................................................... 8

23.6.15 Spreading and Compaction of Embankment and Fills ......... .......... ......... ..... 8

23.6.16 Ant, Termite and other Insect Hill or Nest ..................................................... 8

23.6.17 Draining of Works ........................................................................................... 8

23.6.18 Subgrade Layer ............................................................................................... 9

23.6.19 Tolerances ....................................................................................................... 9

23.6.20 Protection of Embankment Slopes ................................................................ 9

23.6.21 Grassing of Slopes ......................................................................................... 9

23.6.22 Borrow Pits ...................................................................................................... 9

23.6.23 Soil Sterilisation ............................................................................................ 10

23.6.24 Earth Electrode ............................................................................................. 10

23.7 Materials for the Works .............................................................................. 10

23.7.1 General .......................................................................................................... 10

23.7.2 Standards ...................................................................................................... 10

23.7.3 Filter Backfill for Sub-soil Drains ................................................................. 10

23.7.4 Stone for Pitching ......................................................................................... 10

23.7.5 Clay and Cement Bricks ............................................................................... 11

23.7.6 Stone for Platform Surfacing ....................................................................... 11

23.7.7 Gravel Sub-base Material ............................................................................. 11

23.7.8 Crushed Stone Base Course ........................................................................ 11

23.7.9 Precast Concrete Kerbs ............................................................................... 12

23.7.10 Surface Dressing Chipping for Roads ......................................................... 12

23.7.11 Bitumen’s and Tars ....................................................................................... 12

23.8 Drainage and Storm Water ............ ............. ............. ............. ............. ......... 12

23.8.1 Setting Out of Sub-soil and Storm Trenches .............................................. 12

23.8.2 Excavation and Backfilling of Sub-soil Drains .......... ......... .......... ......... ...... 13

23.8.3 Excavation and Backfilling of Piped Storm Water Drains ......... .......... ....... 13

23.8.4 Other Services............................................................................................... 13

23.8.5 Explosives and Blasting ............................................................................... 13

23.8.6 Classification of Excavation ......................................................................... 13

23.8.7

Pipe Culverts ................................................................................................. 14

23.9 Road Pavements and Surfacing ............ ............. ............. ............. ............. 15

23.9.1 Preparations .................................................................................................. 15





Page iii Kenya Power and Lighting Company Limited Substation Bidding Documents – April, 2011

23.9.2 Alignment and Level Control ....................................................................... 15

23.9.3 Thickness and Surface Tolerances ............................................................. 15

23.9.4 Gravel Pits ..................................................................................................... 16

23.9.5 Sub-base and Wearing Course .................................................................... 16

23.9.6 Base Course .................................................................................................. 16

23.9.7 Laying and Compacting Pavement Layers ................................................. 16

23.9.8 Joints Between New and Previous Work .................................................... 17

23.9.9 Kerb Stone ..................................................................................................... 17

23.9.10 Surfacing of Platforms .................................................................................. 17

23.10 Fencing ........................................................................................................ 17

23.10.1 Fencing .......................................................................................................... 17

23.10.2 Dimensions ................................................................................................... 18

23.10.3 Materials ........................................................................................................ 18

23.10.4 Installation ..................................................................................................... 19

23.11 Concrete and Building Works .............. ............. ............ .............. ............ ... 20

23.11.1 Earthworks .................................................................................................... 20

23.11.2 Concrete, Formwork and Reinforcement .................................................... 22

23.11.3 Builder’s Work ............................................................................................... 26

23.11.4 Plaster and Floor Coverings ........................................................................ 30

23.11.5 Carpentry and Joinery .................................................................................. 32

23.11.6 Glazing and Painting..................................................................................... 33

23.11.7 Ironmongery and Metalwork ........................................................................ 34

23.11.8 Plumbing ....................................................................................................... 35

23.11.9 Electrical Installation .................................................................................... 37






fence erected together with all buildings, plant and materials shall be removed, all holes filled andthe site left in a tidy and level condition upon completion of the Contract.

23.5.5 Site Office for Project Manager and Employer ’s Representative

The Contractor shall provide a site office for the Employer's representative.Refer to Chapter 3.14.5 The buildings and the furniture shall remain the property of the Contractor who shall remove andtidy up the sites after completion of the Contract. However the Employer s representative shall alsobe allowed to use these facilities for the duration of the building and erection of electrical works.

23.5.6 Maintenance of Office for Employer’s Representative

The Contractor shall keep all of the buildings provided by him under Clause 23.1.9 in a satisfactoryand fully habitable condition, and he shall maintain and repair all services and all furniture andequipment. He shall provide for collection of refuse, and he shall pay all charges in connection withthe provision of lights and water.

The Contractor shall insure the offices together with all of the contents therein, whether or notprovided by the Contractor, against loss or damage by accident, fire or theft for the duration of theContract.

This Clause shall also apply for the duration of the erection of electrical works.

23.5.7 Survey Instruments and Chainmen

The Contractor shall make available for use by the Employer s representative throughout theduration of the Civil Works any such equipment that he shall reasonably need to monitor thequality of and sign off construction hold-points. Such equipment shall be in first class condition.

This equipment shall be used by the Employer s or the Project Manager's representative only onthe actual substation site. In addition the Contractor will provide all necessary items (skilled labor,

poles, pegs, templates, profiles and all other requisites) for checking the settings out and formeasurement of the works. The equipment will remain the property of the Contractor and he shallmaintain the equipment in first class order and carry out such repairs as are necessary. The cost ofproviding the survey equipment and attendance upon the Employer s or the Project Manager srepresentative shall be included in the rates.

23.5.8 Telephone

The Contractor shall arrange if possible for the installation of a telephone in the offices and shallallow the Employer or the Project Manager site staff free use of this telephone to communicatewith the Employer or the Project Manager in for purposes of this Contract.

23.5.9 Dealing with Water

The Contractor shall keep the whole of the works free from water and he will be deemed to haveincluded in his rates in the bill of quantities for all pumping, shoring, temporary drains, sumps andother measures and provisions necessary for such purposes and for clearing away and makinggood to the satisfaction of the Project Manager damage caused thereby.

The Contractor shall keep all existing drainage channels clear and shall not obstruct the passageof water to or away from any such drainage channels.

23.5.10 Liaison with Police and other Officials

Contractor shall keep in close contact with the Police and other officials of the area concernedregarding their requirements in the control of workmen, movement of traffic, or other matter andshall provide all assistance and facilities which may be required by such officials in the execution oftheir duties.






23.5.11 Explosives and Blasting

The Contractor shall use explosives for blasting in connection with the work only at such times andplaces and in such manner as the Employer or the Project Manager may approve, but suchapproval shall not relieve the Contractor from his responsibilities for injury, loss, inconvenience and

annoyance to persons, the work and adjoining structures, roads, places and things and injury ordamage to animals and property consequent on the use of such explosives. The Contractor shallbe entirely liable for any accident, which shall occur and shall save the Employer or the ProjectManager harmless and indemnified from all claims arising from such use of explosives.

The Contractor shall keep in his office at the site copies of laws applying to the transport, storageand use of explosives and shall also submit to the Employer or the Project Manager a copy of anyinstructions or notices which the Contractor may issue to his staff or workmen or post about thesite in compliance with such laws.

The Contractor shall submit to the Employer or the Project Manager details of the explosives,which he proposes to use, and of his proposals for the transport and storage of explosives.

23.5.12 Works Executed by the Employer or the Project Manager or by other ContractorsThe Employer or the Project Manager reserves the right to execute on the site, works not includedunder this Contractor and to employ for his purpose either his own employees or otherContractors.

The Contractor shall ensure that neither his own operations nor trespass by own employees shallinterfere with the operations of the Employer or the Project Manager or his Contractors employedon such works and the same obligations shall be imposed on the Employer or the Project Manageror his Contractors in respect of work being executed under the Contractor.

The Contractor shall provide unhindered access to all parts of the site to the Employer or theProject Manager, authorised representative of the Employer or the Project Manager and of publicbodies and corporations, and to Contractors employed by the Employer or the Project Manager,and he shall make available to such authorised persons the use of all temporary access tracks inor about the site.

Where the works are being carried out concurrently in one area careful co-ordination of operationswill be required so that interference can be minimised. The Employer or the Project Manager shallhave the power to regulate and rearrange the order of execution of the works under this Contractorto achieve the best co- ordination practicable. The Contractor s programme shall take intoconsideration all information on co-ordination available at the time of its preparation and it shall beflexible enough to allow for subsequent changes that may become necessary. The rates Tenderedfor the works shall include the costs of complying with the requirements of this clause.

23.5.13 Water supplies for the works

The Contractor shall make his own arrangements for the supply of potable water for his staff onsite and water for the works.

The Contractor must make all arrangements including the supply of pumps and motors, labour andthe like to abstract water and must pay royalty to the owners. These costs shall be included in therates for earthworks and pavement.

If the Contractor fails to obtain permission to utilise existing water sources, he may have to drillboreholes near the sites at suitable locations

The Contractor shall obtain the Employer s or the Project Manager s prior approval before utilisingany water source for the works.

23.5.14 Water supplies for the Employer or the Project Manager

A borehole shall be provided to ensure water supply to the substation when in operation, unlessconnection to public water works is more economical.






The Contractor shall arrange for the drilling of a borehole at the sub-station location and the workshall include sitting, drilling, lining and test pumping for 72 hours continuously. The borehole shallbe equipped with a 500-gallon water tank on a 4m stand, an electrically operated submersiblepump including wiring and fittings and all pipe works.

If possible the borehole should be drilled and tested in the early stages of the Contractor so thatthey may provide water for construction, if the supply is adequate. In which case the Contractorshould provide his temporary pumping arrangements as required by clause 1.17 and replacesthem on completion with the permanent submersible pump.

23.5.15 Employers approval of finished works

The Contractor shall obtain the approval of the Employer or the Project Manager for each sectionand each stage of construction. Approval of any section of any stage will not be given and theContractor shall not proceed with any subsequent stage, until all tests required by the Employer orthe Project Manager have been carried out, and the results have shown that the section complieswith the specification. Any works rejected by the Employer or the Project Manager, as notcomplying with the specification shall be replaced by the Contractor at his own expense.

23.5.16 Preservation of trees

No tree shall be removed without prior permission of the Employer or the Project Manager who willlimit the removal of trees to the minimum necessary to accommodate the permanent works.

23.5.17 Survey beacons

During the process of the works, the Contractor shall not remove, damage, alter or destroy in anyway any beacons or survey beacons of the Department of Surveys and Lands. Should theContractor consider that any survey beacons will be interfered with by the works, he will notify theEmployer or the Project Manager, who, if he considers necessary, will make arrangements for theremoval and replacement of the beacon.

If the Contractor removes or disturbs a beacon without the prior permission of the Employer or theProject Manager he shall be liable for the full cost of its replacement together with the full cost ofre-establishing the data relevant to it.

23.5.18 Basic survey and setting out

The sites will be surveyed in detail by the Contractor and the exact locations be agreed with theEmployer or the Project Manager.

The details of beacons and benchmarks shall be provided in the site survey drawings.

The works are located on the drawing and the Contractor shall appoint a suitably qualified surveyor

to set out the works from the beacons and shall plot cross sections at 20 m intervals and submit tothe Employer or the Project Manager for approval.

No separate payment will be made for any works in connection with the setting out of neither theworks nor any other works required by the Contractor to ensure the accurate location andconstruction of the works.

23.6 Earthworks

23.6.1 Bush clearing

The areas of the platform, access road, and borrow pit shall be cleared of all trees, vegetation androots. These shall be neatly stockpiled within 300 m of the site at locations agreed with theEmployer or the Project Manager and shall remain the property of the landowner.






23.6.2 Removal of top soil

The topsoil within the areas of platform and access road shall be stripped to an approximate depthof 200 mm and stockpiled at locations agreed with the Employer or the Project Manager for lateruse on embankment slopes.

Overburden in the borrow pit shall also be stripped to a depth specified by the Employer or theProject Manager and stockpiled for later use in rehabilitation.

23.6.3 Road bed preparation

The „road bed is that part of the ground uncovered by clearing the site, completion of cuts,excavation and removal of unsuitable material as required, on which the platform and roadstructure rest. The "road bed" must be scarified to a depth of 150 mm; water added as considerednecessary, and compacted with a minimum of four (4) passes of a 50 tonne single axle pneumaticsuper compactor. If the roadbed is rock no preparation is necessary.

23.6.4 Order of work

The construction of side cuttings, side drains and embankments shall proceed in methodical andorderly manner. It shall be solely the Contractor s responsibility to arrange his methods andprogramme of work so as to ensure that the earthworks are carried out by the most efficient andeconomical method possible with the type of plant employed of the works.

All trimming of cuttings, and embankments, drains and shoulders to the specified slopes andshapes, shall be carried out concurrently with the earthworks that are being carried out at thatparticular site and level.

23.6.5 Fill Material

“Fill Material” sh all mean material deposited in accordance with these specifications from any ofthe classes specified in order to build up an earthworks construction to formation level as shownon the drawings or as ordered by the Employer or the Project Manager. The CBR of fill for theplatforms shall not be less than 5% at 91% MOD AASHTO density (4 day soaked test) and forroad sub-grade, 9%. The Contractor shall obtain the fill material from a source approved by theEmployer or the Project Manager.

23.6.6 Spoil Material

“Spoil Material” shall mean material excavated in accordance with these specifications from any ofthe classes specified, and which, being obtained from the excavation of side drains, cuttings orbelow the road, embankment is unsuitable for the requirements of the works. Spoil material shallbe removed from the site to a spoil tip which should be within 300 m of the boundary of the site in aneat and tidy manner and shall be approved by the Employer or the Project Manager.

23.6.7 Expansive Material

When expansive material (black cotton, etc.) is encountered, it shall be removed to a depth 600mm below the formation or the existing ground level, whichever is greater. Material removed shallbe stockpiled for later use in slope protection or spoiled to a tip as instructed by the Employer orthe Project Manager.

23.6.8 Surplus Material

“Surplus Material” shall mean material excavated in accordance with these specifications from anyof the classes specified and which is temporarily surplus to the fill requirements and shall be cartedto a designated stockpile for re-use later elsewhere in the works, or to an approved spoil tip.

23.6.9 Formation, Sub-grade and Pavement

The “Formation” shall be the top surface of the earthworks in its final shape after completion.






“Subgrade” of the road and platform shall be the top 150 mm of the fill in embankment, or of theexisting ground in cut, lying immediately below the “Formation”. The “Pavement” shall be the wholeconstruction in the road or paved areas made to support the traffic above the subgrade, comprisingsurfacing and base layers.

23.6.10 Side DrainsWhere side drains are required they shall be shaped by excavating the lines, slopes and widthsshown on the Drawings and finished off so that the formation levels and camber or super-elevationof the formation, level and cross fall of the shoulders, and shape and invert levels of the side drainsare everywhere in accordance with the drawings.

Any excess depth or width excavated from the side drains shall be backfilled and made good to thesatisfaction of the Employer or the Project Manager at the Contractor s expense.

All other types of drains are specified separately in this specification.

23.6.11 Excavation in “Rock”

a) Excavation level

Unless otherwise directed, the formation of the platform can be founded on rock.However, for roads, rock shall be excavated to an average level 150 mm below theformation and in no place less than 100 mm below the formation.

b) Backfilling for Surfaces

Any excess excavation in rock below the formation shall be backfilled and compactedin accordance with clause 2.16. Excess excavation in the invert of drains shall not bebackfilled, but the rock surfaces shall be trimmed, and all loose particles removed, toallow free drainage of water.

c) Excess Excavation of Slopes

Where side slopes are over-excavated no backfilling will be required but the slopesshall be trimmed to a neat shape and safe angle as is acceptable for the Employer orthe Project Manager. The sloping sides of all cuttings shall be cleared of all rockfragments which move when prised with a crowbar. Such excess excavation andadditional work will not be paid for.

d) Hard Material

The provisions of this clause do not apply to hard and common material, whichmaterials shall be excavated to the lines and levels shown on the drawings or asinstructed, within the permitted tolerances.

23.6.12 Setting Out and Preparation for EarthworksThe Contractor shall set out the earthworks and the tips of cuttings and toes of embankments atintervals of 10 m. Reference pegs shall be provided clear of the earthworks and at right angles tothe centre lines, from which the centre lines and levels can be re-established at any time.

Before the construction of any earthworks in the fills, the levels of the existing ground shall beagreed between the Contractor and the Project Manager. If the Contractor fails to take therequisite levels then the ground levels determined by the Project Manager shall be taken ascorrect.

23.6.13 Construction of earthworks to formation

All earthworks up to formation shall be formed and completed to the correct lines, slopes, widthsand levels shown on the drawings and with the subgrade parallel to and at the correct depth belowthe profile, camber, cross fall or super-elevation shown for the finished level, unless otherwisedirected by the Employer or the Project Manager.






Embankments and fills shall be constructed only of suitable material obtained from the excavationof cuttings. If the Contractor encounters material, which he considers unsuitable for earthworks,then he shall forthwith inform the Employer or the Project Manager, who shall instruct the methodof use or disposal of such material. If insufficient material can be obtained from the cuttings,additional material may be borrowed from approved borrow pits.

The Employer or the Project Manager may direct that certain soils be excluded from certain layersand other soils set apart or obtained from borrow and used only for these layers, in which case theContractor shall comply with the Employer s or the Project Manager s directions and shall allow inhis rates for such selection of materials.

23.6.14 Unsuitable Material Information

Where, in the opinion of the Employer or the Project Manager, unsuitable material occurs incuttings, the Contractor shall excavate it to the depths and widths directed and replace it withselected fill material to form an improved formation.

23.6.15 Spreading and Compaction of Embankment and Fills

Embankment and fills shall be compacted in layers not exceeding a compacted thickness of 150mm, provided that the minimum relative density specified is achieved throughout the layer whencompacted. The Contractor shall obtain the Employer s or the Project Manager s approval of theprevious layer before the next layer is spread. If the Contractor wishes to continue placing fillbefore density test results are available, he may do so entirely at his own risk and, should tests fail,then the Contractor must remove both the layer being tested and those placed above it, all at hisown expense.

Unless otherwise specified, embankments and fills shall be compacted to a minimum relative drydensity or 91% Mod AASHTO.

Embankments shall be constructed as far as is reasonable in layers parallel to the formation and to

the full width corresponding to the height at which the work is being carried out from time to time.In no circumstances may a narrow portion of the embankment be constructed first and material“side tipped” to make up the specified width. Density tests must be taken on every layer at afrequency of one for every 1000 m 2 of area. The specified density is a minimum so the Contractormust aim to achieve a higher density than the minimum specifiedto achieve a stable platform withsufficient bearing capacity and stability.

23.6.16 Ant, Termite and other Insect Hill or Nest

Where an ant, termite or other insect hill or nest occurs within the limits of earthworks, all thatportion of the hill or nest which is up to 2m below formation level shall be removed. The cavityformed by the excavation of the hill or nest shall be poisoned with an approved pesticide and be

backfilled with approved material in layers not exceeding 150 mm and compacted in accordancewith Clause 23.6.16.

23.6.17 Draining of Works

All cuttings, embankments and borrow pits shall be kept free of standing water and drained duringthe whole of the construction.

Should water accumulate on any part of the earthworks, either during construction or afterconstruction, until the end of the maintenance period, giving rise to soaking or eroding conditions inthe earthworks, the Employer or the Project Manager may order the Contractor to remove andreplace at the Contractor s expense any material which has been so affected.

All drains shall be maintained throughout the Contract in proper working order.

The Contractor must allow in his rates for draining the earthworks satisfactorily at all stages duringthe construction and arrange his methods and order of working accordingly.






23.6.18 Subgrade Layer

The subgrade of roads, in both cuttings and embankments shall be compacted to 93% Mod AASTHO dry density or as otherwise specified. The subgrade of the platform shall be compactedto 91% Mod AASHTO dry density. The maximum compacted thickness which shall be laid,

processed and compacted at one time shall be 150 mm. The maximum dimension of any particle inthe layer shall not exceed 100 mm.

The layer shall be scarified and water shall be mixed in, or the material allowed to dry out to thecorrect moisture content, and the layer shall then be compacted to the specified dry density, or asotherwise directed. The most suitable moisture content for compaction will be usually in the range of+½ % to – 2 % Optimum Moisture Content.

During the process the final surface of the subgrade layer shall be graded to level, parallel to thecross fall or camber and profile shown upon the drawings or directed by the Employer or the ProjectManager and to the tolerances specified in clause 2.20. Density tests must be taken at frequency ofone for every 250 m 2 of area.

An item is provided in the Bill of Quantities for the additional compaction of subgrade in roads whichshall include the cost of complying with the final tolerances. No separate item is provided for theplatforms where the cost of achieving the final tolerances must be included in general earthworksrates.

23.6.19 Tolerances

The following tolerances will be permitted in the finish of the formation roads and platform:

a) The level of the formation should be within ± 50 mm and – of that specified.

b) On the final trimmed slope of earthworks a variation of ± one fifth of the specified slopewill be allowed.

c) The tolerances permitted in the overall width of the bottom of cuttings shall be ±150mm in the distance between centre lines and the toe cuttings slopes, and plus150mm in the case of embankments.

23.6.20 Protection of Embankment Slopes

The topsoil and expansive material removed from the works shall be placed on embankmentslopes as directed by the Employer or the Project Manager. The slopes shall be trimmed to form agradient not less than 1 on 5 unless otherwise directed.

23.6.21 Grassing of Slopes

The surface of embankment slopes, after placing of topsoil, shall be planted with grass sprigs at

approximately 250 mm centres. Unless instructed otherwise by the Employer or the ProjectManager, the type of grass shall be indigenous, low growing or runner grass. Alternatively thesurface may be turfed. While planting, the area shall be irrigated for as long as necessary toensure that the grass is properly established and has completely covered the ground. Grassshould only be planted in the rainy season.

23.6.22 Borrow Pits

Where it is necessary to borrow material for construction, suitable pits shall be provided by theContractor to the approval of the Employer or the Project Manager.

All borrow pits must be carefully cross-sectioned before and after excavation on order to determinethe quality of earth excavated.

After removal of material for use, the area must be rehabilitated by the Contractor so that it will notprove a hazard to man or beast or a source of erosion. The sides of the excavation must first besloped and then any previously stockpiled topsoil spread as far as possible.






At some borrow pit locations, further cleaning and fencing etc. may be required.

23.6.23 Soil Sterilisation

In order to stop the growth of vegetation and incidence of ants, the Contractor shall apply an

approved herbicide before any spreading of stone over the platform area.Insecticide shall be used around Control Building.

23.6.24 Earth Electrode

The Contractor shall install an earth grid and/or earthing electrodes in trenches as outlined inChapter 22.

Platform Areas- Substation platform areas shall be at least 1.5 times the area required bythe equipment to be installed.

23.7 Materials for the Works23.7.1 General

All materials shall comply with the appropriate standard specification unless otherwise requiredhereinafter.

The Contractor shall before placing any order for materials or manufactured articles forincorporation in the civil works, submit for the approval of the Employer or the Project Manager thenames of the firms from whom he proposes to obtain such materials, etc., together with a list of thematerials and manufactured articles giving the origin, quality, weight, strength, description, etc.,which he proposes that the firms should supply. No materials or manufactured articles shall beordered or obtained from any firm of which the Employer or the Project Manager shall not have

previously approved. All materials shall be delivered to the site a sufficient period of time before they are required for usein the works to enable the Employer or the Project Manager to take such samples as he may wishfor testing and approval. Any materials condemned as unsuitable for works shall be removed fromthe site at the Contractor s expense.

The Contractor may propose alternative materials to those specified, provided that they are ofequivalent quality and, subject to the Employer s or the Project Manager s approval such materialmay be used in the works.

23.7.2 Standards

Concrete pipes, porous concrete pipes, cast iron manhole covers and gratings, bricks, concretekerbs, bituminous surfacing, cement, steel and aggregates shall comply with local or regionalstandards(to be approved by Employer) as follows:.

Precast concrete non-pressure pipes for the culverts and storm water drainage shallcomply with CAS A 17. The pipes shall have ogee joints.

If required, porous concrete pipes for use in sub soil drains shall comply with CAS A17.

Cast iron manhole covers and frames and gratings shall comply with SABS 558 1973 or BS497 and the duty shall be medium weight 100 kg.

23.7.3 Filter Backfill for Sub-soil Drains

This shall be graded crushed stone complying with Clause 23.7.8.

23.7.4 Stone for Pitching

Stone for pitching to drains, inlets and outlets of culverts, to embankments and around structures






shall consist of sound un-decomposed rock.Precast concrete tiles may also be used.

The stone as dressed shall be roughly cubical in shape with minimum dimensions of 150 x 150 x150 mm for a nominal thickness of 150 mm pitching or 225 x 225 x 150 millimetre for a nominalthickness of 225 mm pitching.

Hard stone boulders may be used for grouted pitching only but in this case the size shall be 225mm minimum diameter for a nominal thickness of 150 mm pitching and 300 mm diameter for anominal thickness of 225 mm pitching.

23.7.5 Clay and Cement Bricks

Clay bricks shall comply with CAS 211 and cement bricks shall comply with CAS A 41.

23.7.6 Stone for Platform Surfacing

The stone shall be hard and durable crushed rock with a maximum particle size of 62.5 mm andnot more than 15 % shall pass a 9.5 mm sieve.

The stone layer to be spread uniformly over the finished surface of the platform shall have athickness of 100 mm.

23.7.7 Gravel Sub-base Material

Gravel for the road sub-base layer shall be natural gravel obtained from a proven source and shallcomply with the following requirements:

CBR at 95 % Mod AASHTO density and after 4 day soak Min 30

Plasticity index Max 12

Plasticity product (If x Ip ) Max 200

Maximum particle size (mm) Max 8023.7.8 Crushed Stone Base Course

Material for road base to support the bituminous surfacing shall be crushed rock complying withthe following requirements:

CBR at 97 % Mod AASTHO density and after 4 day soak Min 80

Plasticity Index Max 6

Liquid limit Max 25

Coarseness Index 50 – 70

Fineness Index 5 – 15In addition the grading shall be within and approximately parallel to the following envelope:

British StandardSieve size (mm)

Percent Passingby weight (%)

37.5 100

19.0 80 – 100

9.5 55 – 80

4.75 40 – 64

2.36 30 – 50

1.18 22 – 40

0.6 15 – 30

0.3 10 – 23






0.15 8 – 19

0.075 5 - 15

Equivalent road gravel, produced by a recognised Quarry which has been successfully used asBase 1 elsewhere, may be utilised with the approval of the Employer or the Project Manager.

23.7.9 Precast Concrete Kerbs

Precast concrete kerbs shall be in accordance with CAS 104 and the dimensions shall be 1 000 x300 x 100 mm at the base with a chamfer to 60 mm, over the top 150 mm.

23.7.10 Surface Dressing Chipping for Roads

a) General

All chippings shall consist of tough durable crushed stone cubical in shape and freefrom visible dust and harmful materials such as loam, clay, salt, lime, organic matterand other deletions constituents.

The rock from which the chippings are to be produced shall comply with the following:

o Aggregate crushing value: not greater than 22 %

o Los Angeles Abrasion value: not greater than 28 %

o Sodium sulphate soundness test: Loss on 20 cycles to be no more than 20 %

b) Gradings

Chippings for surface treatment work shall comply with CAS 232 with – “Single sizedcrusher stone for roads”. The following nominal sizes of chippings shall be used:

o

First seal 13.2 mm + 6.7 mmo Second seal 6.7 mm + 1.18 mm

23.7.11 Bitumen’s and Tars

Before any bitumen, bitumen emulsion or tar is delivered to the site the Contractor shall providethe Employer or the Project Manager with a certificate from the manufacturer that the material to besupplied complies in all respects with the specification.

The types of bitumen s required will be as follows:

Prime Coat: MC 30 or 70 or RC 30 or 70 cut back bitumen conforming toCAS 145 or TP 7 Tar conforming to CAS 105

Surface dressing: 150/200 penetration straight run bitumen conforming to CAS144

With special approval: 60% cationic rapid setting bitumen diluted 1: 1 with water

23.8 Drainage and Storm Water

23.8.1 Setting Out of Sub-soil and Storm Trenches

The Contractor shall be responsible for setting out from information provided by the Employer orthe Project Manager and shall include for such work in his rates.

Prior to excavating a section of pipeline, sight rails shall be erected at each end and at eachchange in grade and direction with a maximum distance between profiles of 50 metres.






Site rails and boning rods shall be of substantial construction and shall be painted black and whitein such manner as to indicate clearly the lines and levels to be worked to.

23.8.2 Excavation and Backfilling of Sub-soil Drains

The drains are to be formed by cutting a trench, lining it with double thickness of black shade clothand backfilling with a suitable filter material surrounding a porous concrete pipe. The drains shallhave a minimum of 600 mm depth from platform formation and a gradient of 1 in 100. The internaldiameter of the porous pipes shall be 225 mm and the backfill filter material shall consist ofcrushed stone, as specified in Clause 23.7.8.

The stone backfilling should be placed around the pipe in the trench and compacted thoroughly inlayers so as to ensure that no settlement will occur later in the section of finished platform directlyabove the trench. The discharge ends of all subsoil drains must be carefully protected to avoidblockage and they should be suitably marked.

23.8.3 Excavation and Backfilling of Piped Storm Water Drains

The piped drains are to be formed by cutting a trench, laying a 300 mm internal diameter concretepipe and backfilling with a suitable material. The drains shall have a minimum of 650 mm depthfrom platform formation and a gradient of 1 in 100. The backfill material shall have the followinggrading:

Sieve to BS Amount Passing

20 mm 100 %

10 mm Not less than 85 %

5 mm Not more than 20 %

2.36 mm Not more than 5 %

A 150 mm thick layer of backfill material shall be laid and compacted thoroughly before placing thepipe in the trench. The material shall also be placed and compacted around the pipe for the fullwidth of the trench and shall extend to a level 150 mm above the top of the pipe and compacted toa density not less than 91% of Mod AASHTO density. The rest of the trench shall be backfilled tothe same standard with approved material from excavation or other works.

23.8.4 Other Services

Where trenches pass near or across other services, the Contractor shall take every precautionagainst damaging such services. These services shall be properly supported in the trench untilbackfilling is complete and the backfilling shall be thoroughly compacted under and around suchservices.

23.8.5 Explosives and Blasting

Blasting shall only be carried out on sections of the works for which permission in writing shallhave been given by the Employer or the Project Manager and shall be restricted to such hours andconditions as he may prescribe. Such permission shall not be withheld nor such hours andconditions imposed unreasonably.

23.8.6 Classification of Excavation

For the purpose of measurement of excavation in pipe trenches the excavation will be classified asfollows:

a) Excavation in “rock” for which purpose is defined as:

i) un-decomposed rock occurring in bulk or banks or ledges, the practicableexcavation of which requires explosives or drilling, wedging and splitting.

ii) un-decomposed boulders each exceeding 0.20 m 3 in volume.






b) Excavation in “hard” , which will be held to be material other than rock, theeconomically practicable excavation of which necessitates the use of mechanicalbreakers, or which will reduce the rate of excavation of a back-acting excavator havinga power of at least 0.1 kW per millimetre width of bucket to one third or less of thatachieved by the same excavator in soft excavation at a similar depth.Laterite, iron panand cemented gravels will generally fall into this category.

c) Excavation in “common”, which will be held to be all other material not falling into thecategories of “rock” or “hard” and will include all loose, decomposed boulders less than0.2 m 3 in volume.

For purpose of payment, items are included in the Bill of Quantities for excavation in the foregoingthree classes. The classification of material into these classes shall be agreed by the Employer orthe Project Manager, or on his behalf, and the Contractor as the work proceeds and material shallonly be classified as “rock” or “hard” when the Employer or the Project Manager has given theiragreement prior to its removal.

23.8.7 Pipe Culverts

23.8.7.1 Preparatio n of Foun datio n

The construction of pipe culverts shall be carried out to the lines and levels shown on thedrawings. In order that the foundation material shall be undisturbed, the last 100 mm depth ofexcavation shall be carried out by hand. The excavated surface shall be kept clean and free fromstanding water. Before placing the concrete, the surface shall be lightly compacted.

Excavation in rock shall be carried out to the specified levels and dimensions unless otherwisedirected by the Employer or the Project Manager.

23.8.7.2 Forms

The Contractor will be required to form vertical surfaces to the concrete by means of timber forms.Wrot formwork shall be used for the exposed faces and shall be adequately supported to preventmovement during concreting. Unwrot butt-jointed timber may be used for the unexposed faces.The top surface of the forms shall be set accurately to the required levels or slopes.

23.8.7.3 Ston e Pitch ing

Where shown on the drawings or where directed by the Employer or the Project Manager, stonepitching shall be used to form apron slabs and banks at culvert inlets and outlets, as lining todrains and slopes.

All areas to be pitched shall first be thoroughly cleaned and compacted to a sufficient extent toensure that no subsequent settlement shall occur. At culvert inlets and outlets the level of thepitching shall be the same as the culvert or apron inverts.The pitching stones shall be laid with their longest dimensions perpendicular to the slope and shallbe rammed into the under-surface until firmly bedded and uniform surface true to line and grade isobtained. Pitching stones shall be firmly butted up against the adjacent pitching stones.

Where grouted stone pitching is called for, the stone shall be laid as prescribed, the surfacethoroughly wetted and the spaces between the stones filled with cement mortar or composed ofone part of cement to three parts of approved river sand. The mortar shall be worked into thepitching so as to ensure that all spaces or voids between the stones are completely filled withmortar. The grouted pitching shall then be cured by keeping it continuously covered with wetsacking, or other approved wet cover. For the period of not less than four days from the time themortar was applied.

23.8.7.4 Outl et and Other Drainage Wor ks

Where directed by the Employer or the Project Manager, channels shall be excavated as outlets






Sub-base +5-20

Basecourse +5-10

The finished surface of the Base course shall be such that when tested with a straight edge 3metres long placed in any position and direction, there shall not be any gap greater than 10mmbetween the bottom of the straight edge and the surface. In addition to this requirement there shallnot be any deflection exceeding 20mm from a straight line between any two points 30m apart.Neither of these requirements shall apply across road crowns. These smoothness tolerancesapply to straight profiles and equivalent smoothness tolerances shall be applied to vertical curves.

23.9.4 Gravel Pits

The gravel pits for wearing course and sub-base materials shall be located by the commencementof the Contract.

23.9.5 Sub-base and Wearing CourseNatural gravel sub-base and wearing course material for internal and access roads respectivelyshall comply with the requirements of Section 3, and they must be compacted to achieve, as aminimum, density of 95% of the modified AASHTO density. The frequency of density tests will beone for every 250m² of layer area.

After the completion of Second Stage Works, the gravel-wearing course of the access road shallbe re-shaped, replaced of any gravel loss and re-compacted as directed by the Employer or theProject Manager.

23.9.6 Base Course

Graded crushed stone for base in internal roads shall comply with the requirements of Section 3and it must be compacted to achieve, as a minimum, the density of 97% of the Modified AASHTOdensity. The frequency of density tests will be one for every 250m² of layer area.

The Contractor shall supply and stockpile at site, the required quantity of crushed stone for lateruse, as soon as possible after the commencement of the Contractor. The quantity to be paid tothe Contractor for supply and stockpile shall be the compacted volume incorporated in the Works.The Contractor shall include in his rates, the transport costs of crushed stone to site and anallowance for bulking and wastage, etc.

23.9.7 Laying and Compacting Pavement Layers

The pavement material shall be deposited in such quantity and spread in a uniform layer across

the full width of the area, so that the final compacted thickness is everywhere not less than shownupon the drawings or ordered by the Employer or the Project Manager.

The uncompacted thickness of the layer shall be such that the thickness after compaction shall notexceed the specified thickness. The material shall be thoroughly mixed to a uniform consistencyand large material shall be broken down so that the grading complies with the specification. Largestones or boulders, which cannot be broken down to the required size, shall be removed to anapproved tip.

The spread material shall be brought uniformly to within a range of 90 percent to 110 percent ofthe Optimum Moisture Content, as previously determined for the material, by sprinkling with waterand/or mixing as required.

Compaction shall be carried out by such method and using such plant as the Employer or theProject Manager may approve until the specified minimum dry density is achieved. The Employeror the Project Manager may disapprove any methods of compaction or items of compaction plant,which in his opinion are detrimental to the work.






Additional water shall be applied to the materials during compaction in amounts such as arerequired to maintain the moisture content within the specified limits. Any base course finished witha surface level above the required surface level shall be planed down to the correct level scarifiedre-compacted and finished as specified.

If at any time after compaction the base course dries out sufficiently to lose apparent cohesion, oris damaged by rain, it shall be scarified, aerated and/or watered, re-compacted and finished asspecified above.

The surface of the material shall, on completion of compaction, be well closed, free frommovement under the compaction plant and free from compaction planes, ridges, cracks or loosematerial. All loose, segregated or otherwise defective areas shall be dug out and made good withnew material to the full thickness of the layer and re-compacted all at the Contractor s expense.

23.9.8 Joints between New and Previous Work

The forming of construction joints and the protection of previously completed works shall be carriedout so as to produce a uniformly compacted and homogenous layer free from ridges or other

surface irregularities.Full width working without longitudinal joints is required. When forming a transverse joint at least5m length of the previously laid work shall be incorporated into the new layer.

23.9.9 Kerb Stone

Kerbstones shall be provided at the edges of the roads as shown in the drawings.

Kerbs shall be laid on a cement (C15) bed of 100mm minimum thickness and the joints betweenthe kerb blocks shall be buttered with a 5: 1 sand/cement mortar finished flush with the surface ofthe blocks. In order to obtain a smooth alignment along the curves, 300mm long kerbstones shallbe used instead of 1000mm.

Kerb inlets shall be provided along kerb line at intervals as shown on the drawings, to facilitatedrainage of surface run-off from the road.

23.9.10 Surfacing of Platforms

The stone for surfacing of platform shall comply with the requirements of Section 3 and it must beuniformly spread to a thickness of 100mm over the full-uncovered formation of the platform.

The Contractor shall supply and stockpile at site, the required quantity of stone for later use, assoon as possible after the commencement of the Contract. The Contractor shall trim the stockpileto have a flat surface and rectangular shape with uniform and stable slopes. The Contractor willbe paid for the measured volume of the stockpile and the rate shall include for the supply andtransport to site and forming the stockpile.

If instructed at a later date to lay and spread the 100mm layer of stone on the platform, theContractor shall remove any growth of vegetation, re-compact, trim and sterilise the platformsurface before laying the stone, so that the formation shall comply with the requirements ofClauses 2.19, 2.20 and 2.24. Payment for this work will be negotiated.

23.10 Fencing

23.10.1 Fencing

The Contractor shall construct fencing along the perimeter of substations, including gates where

necessary and shall comply with the requirements of the following clauses.






Fence fittings: ASTM F 626, hot-dipped zinc coated according to ASTM A123

Barbed wire: ASTM A 121, 2.51mm diameter wire in strand (No.12-1/2gauge), 2 strands with 4-point barbs spaced at 125mm, Class

3 zinc coating. Bottom wires: 5mm (No.6 gauge) steel wire, 500 g/m² zinc coating. This

shall be surrounded by a concrete beam (C20) as shown onthe drawings.

Fence fittings: ASTM F 626, steel tension bars and bands, nuts and bolts,weatherproof tops of commercial aluminium alloy, malleablecast iron, or rolled or pressed steel, cast iron and steel fittingshot-dipped galvanised with 500 g/m² according to ASTM A123.

Concrete: 20MPA at 28 days

23.10.4 Installation

Install fencing and gates according to ASTM F 567 unless otherwise indicated, and to drawingsand this specification.

Level ground surface so that space between finished ground surface elevation and bottom of fabricdoes not exceed 50mm.

Plumb and align posts to within 10mm.

Install posts of a gate at same elevation regardless of difference in ground level.

Set posts in concrete footings in form of truncated cone, according to ASTM F 567, and as follows:

FoundationsOrdinary Soil Solid Rock

Line Posts&Centre Rests

TerminalPosts Line Posts Terminal

Depth 1,000mm 1,600mm 300mm 500mm

Diameter at top 250mm 300mm 150mm 150mm

Diameter at bottom 350mm 400mm 150mm 150mm

Make joints in fabric at terminal posts.

Fasten as follows:

a) Every 450mm along top rail, braces and bottom wire;

b) Every 300mm on line posts.

Secure barbed wire to terminal and gateposts with tension bands, and to gate uprights with hooks.

Install bottom wire in middle of last line of mesh.






23.11 Concrete and Building Works

23.11.1 Earthworks

23.11.1.1 Sub -soil Investig ation

The Contractor may ascertain for himself the nature of the sub-soil conditions over the sites of theworks for his additional data, which he may require, for preparation of his bid. The contractor maycollect any other data he deems necessary for his bid

23.11.1.2 Soil Investig ation s

The Contractor shall be required to perform sub-soil tests within the area of the switchyard to thedepth and by the method of test specified by the Project Manager. The details of performing thetest, tools and equipment to be used for, shall be submitted to the Project Manager for approval.

The sub-soil tests shall be carried out by any method as stated hereafter under the supervision ofa qualified person, who shall be subject to approval of the Project Manager.

Should the soil tests result in parameters significantly different from those given for tenderingpurposes, price adjustments for foundations may be adjusted proportionally, subject tonegotiations.

23.11.1.3 Excavation

Excavation for concrete foundations shall be carried out in strict accordance with the requirementsof the Employer or the Project Manager and to fit in with the programme of construction.

23.11.1.4 Shoring and Timbering of ExcavationThe Contractor shall be entirely responsible for the safety of all excavations, for the prevention ofinjury to workmen and for the stability of the faces of the excavation.

The adjacent road surfaces must remain trafficable, and cracking or cave-ins must be avoided. Allshoring and timbering shall be done to the approval of the Employer or the Project Manager, whomay order such shoring or timbering to be strengthened or altered if he considers this necessary inthe interest of the work or to safeguard against accidents to workmen or cave-ins. For the purposeof measurement the following categories of shoring shall apply:

a) Open timber shoring:

This shall consist of vertical boards of not less than 225mm width and not greatercentres than 1.6 metres on both sides of the trench. Held in place by wallings whichshall be strutted apart.

Intermediate boards may be used and must be firmly wedged in position against thewallings.

b) Close timber shoring:

When ordered by the Employer or the Project Manager or dictated by the groundcondition close timber shoring shall be timber boards in contact to give a completesupport to the sides of the trench. The boards shall be supported by wales and struttedas required.

23.11.1.5 DewateringThe whole Works shall be constructed in the dry and the Contractor shall be held responsible forkeeping all excavations free from water, whatever the source or cause may be, and shall properlydeal with and dispose of water by use of sufficient temporary works, plant and appliances so as to






ensure that the whole Works is executed in a satisfactory dry and safe manner. Prices for theexcavation shall be deemed to include for all dewatering operations.

23.11.1.6 Excavation to be App roved

In no case shall broken stone for under drainage or concrete be placed in an excavation until thesurface on which such materials are to be placed has been approved by the Employer or theProject Manager.

The Contractor shall advise the Employer or the Project Manager whenever the bottom of anyexcavation is ready for inspection or whenever it is necessary to cover up the work. In default ofsuch notice the foundation shall on the order of the Employer or the Project Manager be uncoveredby the Contractor and reinstated without extra charge.

23.11.1.7 Disp osal of Excavated Material

All material excavated under this Contract shall be disposed of in accordance with the instructionsissued by the Employer or the Project Manager. Selected material required for back-filling shall

be removed to a tip found by the Contractor and the Contractor shall be responsible for ensuringthat the required amount of spoil is set aside.

23.11.1.8 Other Services

Where trenches pass near or across other services, the Contractor shall take every precautionagainst damaging such services. These services shall be properly supported in the trench untilbackfilling is complete and the backfilling shall be thoroughly compacted under and around suchservices.

23.11.1.9 Backfilling

Backfilling shall be carried out either with selected spoil as set aside, or with imported selectedspoil, or with crusher run, or where specified, with gravel of 38mm nominal size to B.S.C.P. 2006Table 4.

No backfilling shall be done until all the formwork has been removed together with pieces oftimber, cement bags, vegetation and/or other rubbish.

All backfilling shall be compacted in layers not exceeding 150mm thick and shall be sprayed withwater to bring the moisture content to the optimum for dense compaction.

Compaction shall be such as to achieve a minimum of 91% H.C.E. density up to 300mm belowpavement level, and a minimum of 98% above this level up to the underside of the pavement.Compaction is to be tested by a Testing Laboratory.

23.11.1.10 Measurem ent of Excavatio n

All excavation are measured to the net sizes of the foundations etc., no allowance is made ofbattering sides, etc., or for workroom unless otherwise described. No allowance is made forincrease in bulk after digging. Prices are to include for well watering and ramming bottoms to thesatisfaction of the Employer or the Project Manager.

Except where essential, casing is measured to the sides of the column foundation bases belowground level. Should the Contractor excavate the foundations wider than the concrete base sides,the additional excavation, filling and any necessary consequent casing shall be to his account.

The final depth of all column foundation bases are to be decided on site by the Employer or the

Project Manager. The Contractor must give notice to the Employer or the Project Manager whenthe bases have been excavated to the decided level.

No concrete is to be laid until the Employer or the Project Manager has given his written opinionthat a proper foundation had been obtained and the quantity surveyors have been notified in






writing in order for them to take the necessary records for adjusting their original measurementscontained in the Bill. Where vertical faces of excavation are to be cut neat to take the face of aconcrete wall, they are to be protected immediately after cutting with 500 gauge polythene fixedwith 50mm x 50mm vertical timber battens at 800mm centres. Hollow or uneven surfaces causedby inaccurate excavations are to be completely filled with 1:3:6 concrete at the Contractor sexpense.

For the purpose of measurement all excavations shall be divided into the following classes:

a) Rock

Rock will be held to be undecomposed boulders each exceeding a 0,3m³ volume andsolid rock occurring in bulk or in banks or ledges, the practicable excavation of whichwould normally necessitate the use of explosives.

b) Hard material

Hard material will be held to be material other than rock, the excavation of which wouldbe economically impracticable if executed by 7 pick and shovel.

c) Soft material

Soft material will be held to be material more easily excavated than, and not falling intothe categories of “rock” or “hard material”, such as gravel, earth, sand, silt and clay.

23.11.1.11 Measurem ent of Back fillin g

Backfilling shall be measured as the difference between the nominal volume of excavations asspecified and the external volume of the concrete works as specified on the drawings. Thus nopayment will be made for backfilling of overbreak of subsidence. The bill of rates for filling shall bedeemed to cover the cost of all operations described in this specification, including selection ofspoil, excavation from temporary spoil dumps or transporting from excavation, loading andtransporting to site of fill, off-loading, spreading, watering and compacting.

Where the fill material is crusher run or gravel the schedule rates shall include the cost of supply ofthe materials as well as the off-loading, spreading, watering and compacting as specified. Therates entered by the Contractor will be deemed to cover the complete backfilling operationspecified in this document up to the underside of the pavement.

23.11.2 Concrete, Formwork and Reinforcement

23.11.2.1 Materials

Aggregates

Shall conform to CAS 233.

Shall be heaped separately on hard, self-draining surfaces.

Normal size of coarse aggregate shall be 20mm.

Water

Shall be fit to drink.

Reinforcement

Shall conform to the following standards: BS 4449, BS 4461, BS 4482, BS 4483, SABSCKS 158.

Cement

Shall conform to CAS A46.

Shall be either normal Portland or P.C. 15.






Shall be used within 6 weeks of manufacture.

Shall be stored in a manner to exclude any moisture

Shall be stored in a manner to ensure use of the earliest consignment

Different types of cement from different manufacturers shall not be mixed for a single castor structural element.

If concrete is to be exposed Item 4.f to apply for wholeproject.

Additives shall not be used.

23.11.2.2 Befo re con cretin g

Design Mixes

Not less than 2 weeks before the start of concrete work, the Contractor shall submit to theEmployer or the Project Manager for his approval a statement of proposed mix proportions for thevarious grades required in the project. (Note: the grade is the characteristic strength or the cubestrength below which not more than 5% of the result may be expected to fall when tested at 28days). For grades required see Bill of Quantities and Drawings.

The statement shall include proportions of cement, fine and coarse aggregate, and water, themaximum and minimum slump and the target strength for each grade.

A certificate by a recognised laboratory that the proposed mix will meet the requirements mustaccompany the statement.

The proportions stated may not later be altered without the written approval of the Employer or theProject Manager.

Cost of mix designs to be borne by the Contractor.

FormworkFormwork shall be sufficient to leave the concrete finishes specified on drawings and to be withinthe tolerances specified in the following table and to provide an acceptable surface for appliedfinishes, where required.

Line and Level 1mm per metre not exceeding 5mm

Pockets, Sleeves etc. ± 5mm

Bases ±50mm

Where specified as wrot, or the concrete as off good shutter the surface shall be form board orwrot smooth timber of not less than 200mm widths, to impart a smooth finish free of projections,voids, etc., and prices are to include for any necessary rubbing down. The type of ties to be usedshall be such that the required finish is achieved and does not become marred by subsequentcorrosion. Ties to be set out to definite pattern to the Employer s or the Project Manager sapproval. Rubbing down is allowed only after the Emplo yer s or the Project Manager s approval ofthe surface to be treated.

Reinforcement

Shall not be heated or rebent without the Employer s or the Project Manager s permission.

Shall be free from any material likely to impair bond or initiate corrosion.

Shall be bent and fixed according to the Employer or the Project Manager bendingschedules.

Shall be tied with soft iron wire.

Shall be supported to maintain the following minimum cover during concreting.

The greater of the diameter of the bar or 40mm for external unplasteredface.






Shall continue for a minimum of seven (7) days or such longer time as may be required bythe Employer or the Project Manager.

23.11.2.4 Stripping of Formw ork

a) To soffits shall not be struck until 7 days after placing of concrete (but see below forprops).

b) To vertical faces shall not be struck until 14 days after placing concrete

c) Props to soffits shall not be struck until 14 days after placing concrete

d) Shall not be stripped without the Employer s or the Project Manager s approval whohas the power to vary the above items.

Patching

To defective work shall not be undertaken before the item has been shown to the Employeror the Project Manager.

Is a sign of poor workmanship. The Employer or the Project Manager shall have the rightto reject the complete element if an unreasonable amount of patching has to be done, or ifpatching will spoil the appearance of the finished concrete.

23.11.2.5 Records

Are to be kept by the Contractor, showing date and time of each concrete pour, the weatherconditions, the temperature, the number of the cubes which represent the concrete, the slump andany other items which the Contractor and/or the Employer or the Project Manager considerrelevant. These records are to be made available for the Employer s or the Project Manager sinspection when required.

FOUNDATIONS

Foundations to Transformers and for circuit breakers, switches and insulators pedestalsshall be at a depth not less than 1200 mm from the existing ground level.

Cable Ducts and Trenches

The Contractor is responsible for all civil engineering works required for the cable runsbetween switchgear and buildings, in reinforced concrete cable trenches. Cable entries intobuildings and road crossings shall be through 150 mm diameter heavy gauge ducts or in reinforcedconcrete cable trenches Two (2) lines of 150 mm diameter heavy gauge of spare ducts shall beprovided. Trench covers inside the building will be of 6mm thick Metal Chequer plates reinforcedwith 25x25x4mm angle iron welded underneath along the edges and across „X” formation and with

facilities for easy handling on removal, except in areas where heavy traffic is expected wherecovers will be of concrete finished with terrazzo to match the floor finish. Trench covers outsidebuildings shall be of reinforced concrete, designed for the maximum likely imposed loadsappropriate to their location. The trenches and ducts shall be silt proof to prevent silt and debrisfrom entry. The trenches shall be raised to a level that keeps away storm water from flowing in.The trench covers will be constructed such as to allow easy access to the trench by meansof handles or otherwise installed for every fourth slab. Concrete cable trenches shall beadequately drained to soak pits of adequate capacity or shall be connected to the general drainagesystem such that they will remain as dry as possible. The trench covers will be fitted into groovedsides of the trench walls for a flush top of trench and covers. Where the cable trench is crossingroads the ducts shall be constructed in such way that they will be able to withstand the weightimposed on them.

Power cables and control cables shall be laid on suitable galvanized cable racks or cable trays andin separate trenches. Cable entries into buildings shall be sealed to prevent the entry of dust,vermin water, etc., using suitable materials.






23.11.3 B uilder’s Work

23.11.3.1 Setting ou t Walling

The Contractor shall provide proper setting out rods and set out all work on the same for courses,

openings, heights, etc. and shall build the walls and piers, etc. to the widths, depths and heightsindicated on the drawings and as directed and approved by the Project Manager.

23.11.3.2 Materials

Cement and Water

Cement shall be as described in Concrete Works, Section 23.11.2.

Fine Aggregates

Fine aggregates for concrete blocks shall be as described for fine aggregate in Concrete Works.

Coarse Aggregate

Coarse aggregate for concrete blocks shall be good, hard, clean aggregates from an approvedquarry. It shall be free from all decomposted materials and shall be graded up to 7 mm, and all asdescribed for coarse aggregate, Concrete Works.

Concrete Blocks

Concrete blocks for walling shall be provided by the Contractor complying with B.S.6073, andmade in approved block manufacturing machines.

Minimum thickness of blocks in external walls shall be 150 mm, and in internal walls the thicknessshall be minimum 100 mm.

Blocks in external walls shall be hollow type. The volume of the cavities shall be not more than 50% of the gross volume, and the dimensions of the cavities arranged so that each cavity is vertically

continuous when the blocks are bonded. Blocks in internal walls shall be of the solid type. Samplesof the proposed block types shall be approved by the Project Manager before any walling work iscommenced.

Blocks shall be cast under sheds in suitable block manufacturing machines either power driven orhand operated. The form shall be of steel, and accurately made to size to give the required shapeand squareness of block. The concrete shall be vibrated during casting to achieve a dense anduniform concrete. The material shall contain only sufficient water to obtain full chemical reaction ofthe cement and to give proper workability of the constituents.

The ratio of combined aggregate to cement shall not exceed 3:1. The Contractor shall present hisproposal for mix recipe supported by test results for the Project Manager's approval.

Concrete shall have a minimum 28 days strength of 20 N/mm2 in accordance with B.S. 1881.Mixing shall take place in mechanical mixers so as to thoroughly mix the constituents to a uniformconsistency before casting.

On removal from the machine the blocks shall be carefully deposited on edge on boarding or aclean concrete floor under sheds so as to prevent drying out by the sun for 3 days. During this timeblocks shall be kept constantly damp. The blocks may then be laid on edge in the open and keptdamp by spraying or covering with wet hessian or by other means for a further 5 days. The blocksmay then be stacked if required, but not more than one metre high, and in such a way as toprevent damage to the edges and corners.

No blocks may be used in building or be transported to site before having reached required 28days strength criterion. All concrete blocks shall be of even texture and properly mixed ingredients

and all portions of the block shall be properly set and hardened concrete.Blocks shall be free from cracks or blemishes and shall be true to shape and size with clean sharpedges and corners and with corners truly square. Damaged blocks shall immediately be removedfrom the site. No dimension of a block shall deviate individually by more than 3 mm from the






All doors shall be painted as specified under Painting and Decorating. All locks shall be master-keyed with three master keys supplied in addition to three regular keys for each door or gate.

Doors shall be measured by the number of doors of specified dimensions. The rate shall include allsupplies, site works, painting and hardware.

DoorsDoor frames shall be pressed steel frames made from minimum 2 mm thick steel sheeting andreinforced where door closers are fixed. Thresholds shall be made from rolled steel sheetingapproximately 100 mm wide and 12 mm high.

Door shall be filled with mineral wool acoustic insulation and lined both sides with steel sheetingminimum 1.25 mm thick. Total thickness of door shall be 45-55 mm.

All doors shall have fire rating Class A 30.

Placing of doors in accordance with Switchgear building drawing.

Door frames are to be built in to brickwork truly vertical and square with ties per frame. Cement

mortar is to be packed around brickwork built into back of frames. Temporary props to beprovided.

Internal door frames are to be built with six ties per frame while external door frames are to be builtwith height/ten ties per frame.

All door frames are to be from an approved manufacturer and illustrated in the Manufacturer'sCatalogue.

Door frames are to be complete with 100 mm, loose pin steel hinges welded in position andadjustable striking plate. Frames shall generally be built-in during construction of the walls andsecurely fixed. A gap shall be left between the top of the frame and the soffit of the lintel duringconstruction.

Frames shall be adequately strutted to prevent distortion and shall be protected from damageduring other work.

Door frames and similar components shall be fixed with countersunk screws or bolts with headsset into the frames.

Walls shall be built as close as possible to the frames and the gap filled solid with mortar at eachcourse. Render shall be neatly brought up to the frame and well tamped into any remainingcavities. The junctions between window frames or external door frames and external finish or blockwork shall be caulked tight with approved mastic or mortar wherever required, and neatly pointed.Mastic so used shall have long-term resistance against weather, insects and ultra-violet light.

Doors wider than 800 mm shall have three 100 mm hinges. Other doors may have two hinges

except where specified or detailed otherwise.Door stops shall be fitted by screwed fixings where necessary.

The following type of timber doors shall be used unless otherwise instructed by the ProjectManager and shall be from approved manufacture, true to shape and free from twists or warps:

-internal doors shall be hollow core doors consisting of skeleton frames covered with

4 mm plywood for painting. They shall be 47 mm thick overall unless otherwise approved.

23.11.3.12 Alum inium or Steel Windo ws

Unless otherwise indicated windows shall consist of aluminium sub-frame with frosted glass. Thewindows for the equipment rooms shall be block glass type .Windows shall be from an approvedsupplier and the details thereof shall be approved by the Project Manager. Windows shall beoperable and provided with corrosion resistant metal insect screens.

Frames shall generally be built-in during construction of the walls and securely fixed. They shall be






built in to brickwork truly vertical square with six ties per frame. Windows over 1,070m wide are tobe provided with additional head and cill ties.

Placing of windows in accordance with Switchgear building drawings. Widows are to be built in towalls truly vertical square with six ties per frame.

All aluminium or steel windows are to be from an approved manufacturer and illustrated in theManufacturer's Catalogue.

Windows are to be fitted complete with casement fastening, stays etc.

All windows shall have approved burglar bars, and approved means of opening/locking.

23.11.3.13 Door and Windo w Furniture

Ironmongery shall be strongly made, well finished, good quality "stock pattern" articles.Ironmongery for windows and doors shall be galvanised or other approved manufacture forexternal use. Samples of all items shall be submitted to the Project Manager for approval beforethey are used for the Works.

All doors shall be lockable. External doors shall have approved security locks. Three keys for eachlock, clearly labelled, shall be handled over to the Project Manager and all ironmongery shall becleaned, oiled, adjusted and left in perfect working order.

23.11.3.14 MV Swit ch-g ear, Room

Openings for pressure release

In the MV switch-gear room it is necessary to arrange for openings for pressure release in case ofexplosion in one of the switch-gears. To avoid damage in the room/building any pressure shall bereleased through the openings as described.

Location of these openings must be beneath the ceiling on both longitudinal walls in the switch-

gear room. The Contractor must calculate number and size of these pressure openings, andsubmit his proposal for approval.

23.11.3.15 Swit ch gear bu ildin g

Schedule of materials and finish

Room Floor Walls Ceiling Remarks/Notes

11 kV sw.gear

Plastering/paintingTerrazzo

/Terrazzo tiles

Plastering/painting Sheet/plate

Notes:

Ceiling Sheets: = prefabricated/-manufactured color and type in accordion with approval of theEmployer.

Switchgear building: External/internal color in accordance with approval of the Employer.

23.11.4 Plaster and Floor Coverings

23.11.4.1 Materials

Cement and water to be as before described. The sand to be screened through a sieve of 10 to 15and meshes to 1 cm and to be washed if directed.

23.11.4.2 Mixing

All materials for mixing are to be used in proper gauge boxes and they are to be strike measured






and not tramped down in boxes. Proper non-absorbent stages are to be used for mixing andstoring mortar. No foreign matter shall be mixed with the mortar.

The materials are to be mixed dry before adding water through a fine hose spray. Cement mortarwhich has taken its initial set shall not be used.

23.11.4.3 Plaster Thick ness

Unless otherwise specified all wall plasters should not be less than 13mm thick and not more than19mm thick.

23.11.4.4 Cement Plaster

Cement plaster for external use to be composed of one part cement to four parts sand and forinternal use to be one part cement to five parts sand.

23.11.4.5 Form Key

Rake out joints and roughen if necessary to form key for pilaster.

For concrete surfaces, hack and apply 1:1 cement sand slush to form key. Continuously wet for 7days and the apply plaster.

All brickwork and concrete works should be brushed down to remove dust and loose material.

23.11.4.6 Wetting

All internal and external brick or concrete surfaces are to be wetted well before plastering.

All cement plaster must be kept wet for at least 7 days.

23.11.4.7 Repairing Defects

All defective plaster, cracks, hollows, etc., are to be cut out to a rectangular shape, the edgesundercut to form a dovetail key and to be made good to finish flush with the edge of thesurrounding plasterwork.

All patches will be to the approval of the Employer or the Project Manager and if the defects cannotbe made good satisfactorily then the whole surface is to be removed and re-plastered at theContractor s expense.

23.11.4.8 Grano lith ic Floo r

Preparation of bases

Clean all bases thoroughly to remove all dirt, dust, rust and oil. Hack and expose as muchcoarse aggregate as possible. Wet base for 24 hours before laying finish and removesurplus water. Brush neat cement slurry onto surface 20 minutes before laying finish.

Materials

Use approved, clean, washed granite chippings or other approved stone graded in sizefrom 7mm down with not more than 20% fine material passing 200 micron mesh sieve.Mix to comprise 1 part Portland cement, 2 parts coarse aggregate and 1 part river sand byvolume. Use smallest quantity of mixing water needed to give adequate mouldability. Lay toa finished smooth surface of 40mm and finish off with a steel trowel. Continuously wetfinished surface for 7 days.

23.11.4.9 Wall Tilin g

Ensure that the base to receive tiles is level, dry and clean with no loose and friable areas orsurface dusting. Prepare and use adhesive to manufacturer s recommendations to form a bed notmore than 3mm thick. Lay tiles dry and tamp well down to ensure a proper bond with base and alevel surface. Grout up joint with approved white cement.






23.11.5 Carpentry and Joinery

23.11.5.1 Timber

To be best quality procurable, free from sap, white wood, shakes, large, loose or dead knots,

waney edges and other defects. Timber to be sawn to hold the full specified sizes and die square.Timber and timber products to be guaranteed free from borer and beetle infestation of any kind.

Any defects traceable to such infestation shall be rectified by the Contractor at his own expense,including any timber adjacent to the affected parts. This guarantee shall be valid for a period oftwo years from date of handing over the works.

Timber to be well seasoned and kiln dried to a moisture content not less than 10% or more than12%.

Softwood

Softwood for carpentry to be selected straight grained timber graded in accordance with therelevant National or regional Standards.

Laminates are not to exceed 25mm thickness and are to be finger jointed.

Hardwood

Hardwood to be best quality selected straight grained kiln dried of the type specified.Submit sample 600 x 150 x 38mm for approval.

Structural Timber

Timber for non-structural framing, battens and brandering to be merchantable grade andshall conform to the relevant National or regional Standards.

Structural timber to be merchantable grade marked “M” and shall conform to the relevantNational or regional Standards.

Glued laminated timber shall conform to the relevant National or regional Standards andshall bear the mark of the Kenya Bureau of Standards.

23.11.5.2 Workmanship

All timber for carpentry work to be in as long lengths as possible and all laps and joints to beplaced over points of support. All timber to be finished clean, smooth and free from tool marks.

23.11.5.3 Nailing

All nails are to be of the best quality and of gauge, length and strength suitable for work. They willbe long enough to enter the second timber at least one half their entire length before punching.

Skew nailing will only be permitted in the framing.23.11.5.4 Sizes

All sizes specified are nominal before dressing or shaping. 2.5mm will be allowed off nominal(sawn) sizes for each face.

23.11.5.5 Prices

Timber described as “sawn” as to include all workmanship and labour in preparation andconnecting together by lapping, notching, splay or birds mouth cutting, halving, scarfing and for allnails and spikes.

Timbers unless otherwise stated, shall include for fixing with nails of the approved size and type.

Where describes as “plugged”, it shall include for fixing to concrete, brickwork or similar materialwith suitable plugs. Suitable patented expanding sockets may be used if approved.






23.11.6 Glazing and Painting

23.11.6.1 Glass

All glass is to be of approved manufacture, free from bubbles, waveness, scratches or other

imperfections and is to be well bedded, puttied and back puttied and secured with glazing pins orclips in steel sashes or with sprigs in wood sashes.

All glass shall be carefully cut to the required sizes so that all panes of figured or textured glass areuniform in appearance with the pattern parallel to the edges and wired glass shall be so cut thatthe wires are parallel to the edges.

23.11.6.2 Putty

Putty for glazing to steel sashes is to be of approved proprietary brand specially made for use withsteel sashes and shall conform to the relevant National or regional Standards. Best quality linseedoil putty conforming to the relevant National or regional Standards to be used for wood sashestinted as necessary when used for glazing to hardwood. Rebates are to be thoroughly back

puttied before glazing and all putty is to be carefully trimmed and cleaned off so that back puttyfinishes level with the top of sections internally, external putty covers sight lines exactly andfinished straight and true. Rough surfaces to putty will not be allowed and any defective putty willbe cut out and replaced at the Contractor s expe nse.

Rebates of wood sashes are to be given one coat of priming immediately before glazing.

23.11.6.3 Mirrors

Glass mirrors are to be of the thickness specified, of selected quality glass, silvered on back, withprotective sealing coat and arrised edges, unless otherwise described.

23.11.6.4 Generally

Allow for removing and replacing all cracked, broken or defective glass and leave thoroughly cleanand perfect at completion.

23.11.6.5 Materials for Decoratio n

All paints, primers, varnishes, emulsions, stopping, etc., to be of approved manufacture.

The Contractor is to use proprietary ready mixed paints obtained from an approved supplier.

When a coat of proprietary paint is applied, the manufacturer s priming and previous coats suitablefor the particular type are to be used.

All materials must be brought on to the site in unopened tins, and no dilution or adulteration will bepermitted, unless approved by the Employer or the Project Manager.

23.11.6.6 Emu lsio n Paint

Emulsion paint shall be PVA (Polyvinyl Acetate) alkali-resisting formulated with high washabilityand capable of resisting a 8000 scrub test. The first coat to be specifically formulated base coat fordirect application to the specified surface.

23.11.6.7 Filters

Higher grade cellulose fillers are to be used internally and premixed filler to be used externally.

23.11.6.8 High Glos s PaintsPrimers

Primers for application to bare metal to be red oxide primer for iron and steel. For galvanised






metal to be an approved zinc chromate or galvanised iron primer. For application on wood orplaster etc., to be an approved alkali primer.

Finish Enamels

Finish enamels to be synthetic enamel high capacity paint with high coverage and high gloss finishunless otherwise described.

23.11.6.9 Workmanship

All surfaces are to be free from moisture, dust, grease and dirt and rubbed down smooth accordingto approved practice.

All plaster to be free from efflorescence and treated with one coat of petrifying liquid, approvedsealer or alkali primer if required. Hard wall plaster to be glass papered before decorating.

Rectifying defects to decorated surfaces due to dampness, efflorescence, chemical reaction, etc.,will be to the Contractor s account, as these surfaces must be checked and the appropriateprecautions taken before applying the decoration.

Metalwork must be scraped free of rust, primed as described and finished as later specified.

Galvanised sheet iron, pipes, etc., are to be cleaned down to remove manufacturer s ammoniateddichromat protective covering, primed as described and finished as later specified.

Coated pipes are to be cleaned down, stopped and primed with one coat of aluminium primer andfinished as later specified.

All knots in woodwork to be treated to prevent bleeding. Large or loose knots to be cut out and bereplaced with sound wood, or cut back and filled. Small knots to be treated with two thin coats ofShellac in methylated spirits. Woodwork to be glass papered to a smooth surface with all sharparrises removed, all cracks, crevices, holes, etc., to be scraped out, primed as described andstopped with hard stopping, faced up and rubbed down to an even surface and finished as later

specified. All metal and woodwork to have the specified number of coats in addition to the priming coat.

Every coat of paint must be a good covering coat and must dry hard and be well rubbed down to asmooth surface before the next coat is applied, otherwise the Contractor will be required to applyextra coats as his own expense.

Each coat of paint to be of a distinctive colour: sample colours are to be papered for the final coatwhich is to be an approved colour scheme and must not be applied without the permission of theEmployer or the Project Manager. After undercoats are on, the painter shall check all work andgrain fill as necessary with filler as described.

Note:

a) All paints specified are to be obtained from an approved manufacturer and used instrict accordance with their instructions. Their representative will check the paintsbeing used and the method of application and will advise accordingly.

b) This section of the work to be carried out by an approved firm of decorators who mustallow for the very best finish possible and of the highest quality obtainable.

c) The prices must allow for the removal and refitting of all beads, fittings, fastenings,ironmongery, etc., removed for decoration purposes to be carried out by skilledtradesmen of the appropriate trade.

23.11.7 Ironmongery and Metalwork

23.11.7.1 General






All ironmongery shall be of the best respective types required and no alternative articles will beaccepted unless approved. Articles described as brass must be solid brass and not brass finish.Chromium plated articles must be plated satin finish on solid brass or other approved metal.

Where items for ironmongery are required to be fitted to steel door frames, etc., the Contractor

must ensure that the manufacturer makes provision for the correct fitting or lock striking plates,hinges, cleat holes, bolt keeps, etc.

23.11.7.2 Lo cks and Keys

Locks are to be two lever unless otherwise described. All locks are to be provided with two keyswhich must be handed over to the owner on completion of the Works with identification labelsattached.

23.11.7.3 Steel

Steelwork for general building construction is to be of approved manufacture complying generallywith the appropriate British Standards and free from all defects, oil, dirt, loose rust, scale or other

deleterious matter.

23.11.7.4 Standar d Steel Wind ow and Door Frames

All steel windows and door frames are to be from an approved manufacturer and illustrated in theManufacturer s Catalogue.

Windows are to be fitted complete with casement fastening, stays, etc.

Door frames are to be complete with loose pin steel hinges welded in position and adjustablestriking plate.

23.11.8 Plumbing

23.11.8.1 Regulations

All plumbing and drainage work shall be executed strictly in accordance with the Local Authority sBy-Laws and Regulations.

23.11.8.2 Lic ensed Plum bers and Drain layers

Only licensed plumbers and drain layers shall be employed to carry out such works.

23.11.8.3 Sheet Iron

All sheet iron to be approved brand, galvanised and of the thickness specified and shall conform toBS 2989. Galvanised iron nails shall be used for galvanised sheet iron where required.

23.11.8.4 Flash in g, etc.

Flashing etc. shall be properly lapped at angles and passings. Dress flashing 38mm into groovesand 6mm up at back and wedge with rolled wedges. No screws or nails are to penetrate gutters orflashings. Provision to be made for expansion and contraction under changes of temperature.

23.11.8.5 Eaves Gutt ers and Rainw ater Pipes in Sheet Iron

Eaves gutters and rainwater pipes shall be formed to sizes and shaped as specified. The rainwaterpipes shall have close welted and soldered seams, and the joints between lengths are to beriveted and soldered. All joints in the straight length and at angles, stop ends, etc., are to be rivetedand soldered. Sizes of gutters are to be effective sizes.

The eaves gutters shall be fixed to falls to outlets on 6 x 25mm mild steel gutter brackets bent tosuit the profile of gutter and twice holed for and screwed to woodwork or bolted to steel at notexceeding 1.00 metre centres. Alternatively, approved fascia brackets may be used.






23.11.8.6 Plastic Pipes

Plastic pipes and fittings shall conform to the relevant National or regional Standards and be fixedincluding brackets in strict accordance with the manufacturer s printed instructions.

23.11.8.7 Cast Iron PipesCast iron pipes and fittings shall conform to BS 416. Heavy-duty cast iron pipes and fittings shallconform to BS 1130. All pipes and fittings are to be coated with an approved preservative. Pipesare to be jointed with gaskin and caulked with molten lead.

23.11.8.8 Steel Pip es

Steel pipes and fittings shall conform to BS 143 and the relevant National or regional Standardsand be galvanised. Pipes are to be jointed with hemp and red lead. Medium quality pipes are tobe used, unless otherwise specified. Fix to roof timbers with stout galvanised clips and to wallswith galvanised hinged holder bats with brass pins at not exceeding one metre centres, built intowalls with cement mortar. Sling pipes to soffits on 6 x 32mm mild steel strip fixed around pipes

with 6mm galvanised bolts with ends split and flanged and cut pinned to concrete soffits.

23.11.8.9 Copp er Pipes and Fittin gs

Copper pipes shall conform to BS 659; BS 1306 and BS 1386 shall be solid drawn seamlesssupplied in straight random lengths, round clean, smooth, free from internal or external grooving,other defects and deleterious film.

All copper pipes carrying hot water are to be supported so as to allow free movement forexpansion and contraction, particularly at the end of long runs where a change of direction takesplace. Fix tubing to walls with brass hinged holder bats with pins at not exceeding one metrecentres built into wall with cement mortar. Fix to soffits as described for steel pipes.

Fittings and couplings etc., for use with copper pipes shall be of the manipulative compression jointtype or other approved type. All fittings, etc., are to be made from suitable corrosion resistantcopper alloy, sound and clean, without flaws or laminations and full bore throughout. All fittingsand their component parts shall be capable of withstanding an internal hydraulic pressure of 2.20MPa without showing signs of leakage or other defects.

23.11.8.10 Sizes of Pip es

The sizes of pipes, traps, etc., are nominal bore except for PVC which shall be external diameter.

23.11.8.11 Traps

Traps shall be brass, copper, polythene or cast iron as specified. Generally traps to shower trays,baths, lavatory basins, drinking water foundations and domestic sinks shall be tubular copper toBS 1184 of the same size as the waste outlet of the fitment, and shall have tails to suit the wastepipe to which they connect.

23.11.8.12 Stain less Steel

Stainless steel to be the austenitic type and shall comply with BS 970 EN58 series and unlessotherwise described, to 0.9mm thick in 18/8 quantity and shall be entirely non-magnetic.

23.11.8.13 Brassware

Brassware is to be of the best quality and equal to the samples approved. All stop valves, bib taps,hose union bib taps and pillar taps shall comply with BS 1010 or SABS 226 and shall have washer

plates so secured as to lift with the spindle.Cold-water taps shall in every case be fixed at the right hand side of sanitary fittings.

All ball valves shall comply with BS 1212 and shall be of sizes and for the pressure indicated or






specified. The loose orifice seats shall be of nylon for sizes 15 and 20mm and bronze for sizes 25,40 and 50mm. Ball valves shall be supplied and fixed complete with copper floats to BS 1968 orwith plastic floats not less robust and having a lifting effect not less than a BS 1968 copper float forthe same duty.

23.11.8.14 Fire Equi pm ent

Portable fire extinguishers are to comply with the relevant National or regional Standards. All fireequipment to be of a type and manufacture approved by the Fire Officers Committee and the Local

Authority concerned.

Portable fire extinguishers shall be provided under this Contract. Portable, wall mounted, handheld extinguishers shall be 5.5kg pressurized control discharge BCF units. The number of unitswithin the Substation shall be a minimum of 4 Number.

The body of the extinguisher shall be seamless, welded and brazed as appropriate.

The extinguisher shall be capable of being released by means of a lever-operated valve providedwith a safety pin.

Extinguishers shall be capable of controlled partial discharge.

The type shall be of that recharge unit that is locally available.

The extinguishers shall be walls mounted and attached and located in a manner affording quickrelease from the supporting bracket. They shall be installed so that the top of the extinguisher isnot more than 1.5meters above the floor. In no case shall the clearance between the bottom of theextinguisher and the floor be less than 0.1 meter. The extinguishers shall be positioned so that theinstructions for operation face outwards .

23.11.8.15 Excavati on , etc.

Excavate bottom of drain trenches to an even fall and lay 75mm cement concrete (Grade 10-20mm stone) bed under pipe and support each length of drainpipe with stoolings of cementconcrete (Grade 10-20mm stone) behind each collar and haunch up half way around externaldiameter of the pipe.

23.11.8.16 Generally

No holes are to be cut through reinforced concrete work unless approved. Where possible sleevesare to be cast into concrete. Where drainpipes pass through walls, etc., they must be arched overto prevent any loads being transmitted from the structure.

23.11.8.17 Testing and Cleaning All sheet metalwork shall be carefully and efficiently inspected and tested on completion and leftperfectly watertight.

All defective work shall be taken out and replaced with new work at the Contractor s expense.

At completion of plumbing and draining installations, clean down and flush pipes, traps, etc., washsanitary fittings and test the whole to the satisfaction of the Local Authority and the Employer or theProject Manager including making good and re-testing until found perfect. The Contractor mustprovide all necessary equipment to carry out any tests required.

23.11.9 Electrical Installation

23.11.9.1 Scop e of Wo rks

This section of the specification relates to the supply, installation, testing and commissioning of thecomplete electrical services within the control building, including:






i) LV Switchgear and Distribution

ii) Lighting

iii) Small Power

A full specification of the electrical equipment proposed by the Contractor shall be included in theBid.

The Employer reserves the right to reject any of the contractor suppliers if he feels the productdoes not meet with the contract specification.

23.11.9.2 Electric al Servic es General Descrip tion

The complete electrical installation shall comply with all local standards, Wiring Rules, regulationsand rates.

Should there be any conflict between local standards and what has been specified the Contractorshould draw it to the attention of the Project Manager.

23.11.9.3 Lo w Voltag e Switc hg ear

All switchboards shall conform to standards given above.

23.11.9.4 Lighting

Luminaries

Luminaries shall be fluorescent lamps except for the toilets and outdoor lighting (except switchyardand perimeter lighting) where GLS lamps can be utilised. In switchgear room: 250 lux is required.In offices 500 lux is required.

All luminaires shall be supplied, installed and tested by the Contractor.

All metalwork on the luminaires shall be connected to an insulated earth protective conductor.Battery room luminaires are to be explosion proof.

Lighting Control Switches

Lighting control switches shall be flush pattern with white finished plates.

Grid switches shall have 5 or 10 amp rating, generally where fluorescent discharge luminaries arecontrolled switches have 10 amp rating whereas with low energy PL lamp, 5 amp switches shall beinstalled.

Light switch in battery room to be spark (explosion) proof.

23.11.9.5 Socket Outlets and Acc essories

Reference should be made to relevant local standards Wiring Rules and regulations.

Socket outlets to be mounted at 300 mm above final floor level.

23.11.9.6 Conduit

Conduit cast into the building structure shall be of the heavy duty PVC type as specified in theStandard Specification. PVC conduits shall not be fixed to the surface of the structure.

23.11.9.7 Trunking

Mild steel trunking is to be fixed to timber trusses in the ceiling void. Trunking is to be utilised tofeed all lighting and power circuits.

23.11.9.8 AC Installatio n

The Contractor shall supply and install wiring and insulator for the AC units, including final






connection to the units.

23.11.9.9 Earthing

IBR roof, if applicable, is to be connected to the earth grid via 25 x 3mm copper tape at four

corners of the building.




24. STEEL STRUCTURES




Chapter 24: Steel Structures

Page iKenya Power and Lighting Company Limited Substation Bidding Documents – April 2011

Contents

24 STEEL STRUCTURES ........................................................................ 1

24.1 General .......................................................................................................... 1

24.1.1 Location of the Works .......... ......... ......... .......... ......... .......... ......... ......... .......... 1

24.1.2 Type of Works .................................................................................................. 1

24.2 Particulars of Electrical System ............. ............. ............. ............. ............. . 1


24.4 Standards, Units and Language ............. ............. ............. ............. ............. . 1

24.5 General Requirements ................................................................................. 1

24.5.1 Sequence of construction ............................................................................... 1 24.5.2 General Design Particulars ............................................................................. 2

24.5.3 Manufacture ..................................................................................................... 3

24.6 SteelStructure Design Criteria..................................................................... 4

24.6.1 General ............................................................................................................. 4

24.6.2 Loads on Structures ........................................................................................ 4

24.6.3 Electrical Clearances ......... ......... ......... .......... ......... .......... ......... ......... ......... .... 5

24.6.4 Phase Spacing ......... .......... ......... ......... .......... ......... ......... .......... ......... ......... .... 6

24.6.5 Shield Angle ..................................................................................................... 6 24.6.6 Steel Structures, main dimensions ................. ......... ......... .......... ......... .......... 6

24.7 Design Requirements for Steel Structures ................................................ 6

24.7.1 Steel Characteristics ....................................................................................... 6

24.7.2 Design Stresses ......... ......... .......... ......... ......... .......... ......... ......... .......... ......... .. 7

24.7.3 Detailing Requirements ......... .......... ......... ......... .......... ......... ......... .......... ........ 9

24.7.4 Ladders and Steps ........ .......... ......... .......... ......... ......... ......... .......... ......... ..... 10

24.8 DesignRequirements for Steel Structures ............................................... 10

24.8.1 Technical Documents ......... .......... ......... ......... .......... ......... ......... .......... ......... 10 24.8.2 Quality Assurance Program (QAP) ........ .......... ......... ......... .......... ......... ........ 10

24.8.3 Manufacturing ................................................................................................ 10

24.8.4 Welding .......................................................................................................... 11

24.8.5 Numbering of Parts ........................................................................................ 11

24.8.6 Galvanising .................................................................................................... 12

24.8.7 Packing, Storing and Transport ......... ......... .......... ......... ......... ......... .......... ... 12

24.8.8 Test Program ................................................................................................. 12





Page 1Kenya Power and Lighting Company Limited Substation Bidding Documents – April 2011

24 STEEL STRUCTURES

24.1 General

24.1.1 Location of the Works

The location(s) of the site(s) are as described under Chapter 2 Scope of Works .

24.1.2 Type of Works

The works covered by this part of the Employers Requirements include the following:

Design of all gantries (consisting of pylons and girders) and steel support structuresnecessary for the relevant substation(s);

Manufacture of steel structures;

Galvanising of steel structures;

Timely delivery of steel structures to site(s) including transport, handling, on/off loadingand storage;

Any other works necessary for full compliance to KPLC standard as well as theconstruction of a fully functional substation.


Steel structures shall be capable of operation under the general electrical parameters asspecified in Sub-chapter 3.6.2.


The steel structures shall be capable of operation under the atmospheric conditions as specifiedin Sub-chapter 3.6.1.

It is jointly the Contractors and manufacturer’s responsibility to be familiar with any other climaticand physical conditions pertaining to the specific sites as defined in Chapters1-3 and to allow forall conditions in designs.

24.4 Standards, Units and Language All equipment shall be designed, constructed and tested in accordance with requirements of thelatest version of the standards specified except to the extent explicitly modified in thisspecification:


24.5 General Requirements

Chapter 3 Part A General Requirements shall apply. The following Sub-Chapters add to thecriteria so specified.

24.5.1 Sequence of construction

The sequence of supply of steel structures to site shall be determined by taking into accountwhen the various structures actually are needed from the point of view of the overall project






program.

24.5.2 General Design Particulars

24.5.2.1 Design and Standard isatio n

All design carried out by the Contractor shall comply with these Specifications and shall take intoaccount all requirements of the works. The Contractor shall be entirely responsible for all designcarried out by him. All design calculations shall be subject to the approval of the Employer or theProject Manager.

The steel structures shall be designed to ensure satisfactory operation in which continuity ofservice is the first consideration and to facilitate inspection and repairs. All structures suppliedshall also be designed to ensure satisfactory operation under the atmospheric conditionsprevailing at the Site, and under such variations of load as may be met with under the prevailingworking conditions.

Except where otherwise specified or implied, the structures shall comply with the latest applicable

Standards of the British Standards Institution, hereinafter referred to as BS, or to technicallyequivalent National or International Standards. The standards used shall be to the approval ofthe Employer or Project Manager.

Copies of any Standards proposed in substitution for BS must be submitted with the Tenderaccompanied where required by English translation of the appropriate sections.

24.5.2.2 Inter-chan geabilit y of Parts

Corresponding parts of all materials shall be made to gauge and shall be interchangeable. Whenrequired by the Employer or the Project Manager the Contractor shall demonstrate this quality byactually inter-changing parts.

24.5.2.3 Drawin gs , Samp les and PatternsDrawings to be submitted with the Tender and drawings to be submitted for approval by thesuccessful Bidder are specified in the Schedules. The Contractor shall also submit any furtherdrawings, or copies of drawings, samples and patterns at his own expense, as may bereasonably required by the Employer or the Project Manager during the design, manufacture anderection of steel structures.

The Contractor shall prepare and submit to the Employer or the Project Manager for approvaldimensioned general and detailed design drawings of all the structures. Drawings alreadysubmitted by the Contractor and approved by the Employer or the Project Manager, and theEmployer or the Project Manager in writing as shall be thereafter submitted by the Contractor andapproved by the Employer or the Project Manager shall not depart from such drawings withoutpermission.

All dimensions marked in SI units on drawings are to be considered correct, althoughmeasurements by scale may differ therefrom.

Approval of drawings shall not relieve the Contractor of his obligations to supply the structures inaccordance with the specification.

The Contractor is responsible for any errors that may appear in the approved documents. Heshall as soon as an error has been detected, deliver the corrected documents to the Employer orthe Project Manager for re-approval.

All legends and notes on drawings provided by the Contractor shall be in the English language inaddition, if necessary, to that of the country of origin.

All drawings shall be dimensioned in millimetres (or meters) and drawn to one of the preferredscales quoted in Table 7 of BS Publication PD 6031 and on paper of the appropriate size fromthe International Series of A Sizes.






The despatching of drawings and other documents to the Employer or the Project Manager shallbe effected by the most expeditious way of transport.

24.5.2.4 Guarant ees and General Particu lars

The steel structures shall comply with the general particulars and guarantees stated in theSchedules in this section.

The Contractor shall be responsible for any discrepancies, errors or omissions in the particularsand guarantees, whether such particulars and guarantees have been approved by the Employeror the Project Manager or not.

24.5.3 Manufacture

24.5.3.1 Places of Manufacture, Sub-Contractors and Dates for Comp letion

The manufacturer’s identity and places of manufacture, testing and inspection before shipmentfor the various structures shall be specified in the Schedules in this section and shall not be

departed from without the agreement of the Employer or the Project Manager.Completion of steel structures shall be in time so as not to cause delays of the overall substationconstruction and erection works.

The actual dates of readiness for despatch of and the dates for completion of the various portionsof the structures shall be communicated to the Employer or the Project Manager in good time.

As soon as practicable after entering into the Contract, the Contractor shall, having obtained theEmployer’s or the Project Manager ’s conse nt in accordance with the Conditions of Contract,enter into the Sub-Contracts he considers necessary for the satisfactory completion of thesupport structures.

All Sub-Contractors and Sub-suppliers of components and materials shall be subject to the

approval of the Employer or the Project Manager. Information shall be given on each Sub-ordersufficient to identify the material or equipment to which the sub-order relates.

24.5.3.2 Work Plans and Progress Reports

Programmes and progress reports shall be provided by the Contractor in a form approved by theEmployer or theProject Manager.

24.5.3.3 Inspec tion and Testing

All materials used for the steel structures are subject to inspection by the Employer or the ProjectManager and it is the Contractor’s responsibility to advise the Employer or the Project Managerwhen equipment and materials are available for inspection, at least 2 weeks in advance.

The Contractor shall under the Contract carry out the tests as in the opinion of the Employer orthe Project Managerare necessary to determine that the structures comply with the conditions ofthis Specification.

All materials used shall also be subjected to and shall withstand satisfactorily such routine testsas are customary in the manufacture of the types of structures included in this project.

All tests shall be carried out to the satisfaction of the Employer or the Project Manager and, ifrequired, in his presence.

If testing is decided on, a test programme shall be submitted to the Employer or the ProjectManager for approval at least 1 month ahead of the commencement of testing.

Measuring apparatus shall be approved by the Employer or the Project Manager and if requiredshall be calibrated at the expense of the Contractor at an approved laboratory.

The Contractor shall be responsible for the proper testing of the completed materials supplied bya Sub-Contractor to the same extent as if the materials were completed or supplied by the






Contractor himself.

The Contractor shall supply to the Employer or the Project Manager suitable test pieces of allmaterials as required. If requested by the Employer or the Project Manager test specimens shallbe independently tested at the expense of the Contractor by an independent testing authority

selected by the Employer or the Project Manager.24.5.3.4 Subm ission of Drawings

After award of Contract, the Contractor shall submit, within two months, copies of drawings andcalculations to the Employer or the Project Manager in triplicate for examination and approval ofwhich one set will be returned with comments or approval. Manufacture may start prior tocomplete approval of any structure but at the Contractor’s own risk.

24.5.3.5 Spares

Any spare materials shall comply with the requirements of this Specification including compliancewith the specified tests and interchangeability.

24.5.3.6 Packing and Transport ation

All materials shall be carefully packed for transport by sea, rail and road, and in such a mannerthat the packing provides adequate protection against all climatic conditions experienced intransit and storage at site during the construction period.

24.6 Steel Structure Design Criteria

24.6.1 General

The structures shall be designed to provide at least the minimum phase and earth clearances,also under conditions of swing and sag.

Where typical layouts of the switchgear are shown on drawings attached to this Specification,structures shall be of the approximate general proportions given on these drawings.

All structures shall be designed to fit the actual equipment and apparatus, which they shallsupport.

The rigidity of the structures shall be such that the alignment of the apparatus, which they carry,shall not be disturbed by the loads to which the structures are subjected. Lattice girders shall befabricated with a camber to compensate for the horizontal deflections.

Busbar dead end structures shall be designed so as to be suitable for future busbar extension.

24.6.2 Loads on Structures

The assumed maximum simultaneous working loadings on the structures shall be as follows:

24.6.2.1 Win d Lo ading s

To be assumed working on the whole projected area of all conductors, insulators and apparatuscarried on the structures. For lattice steel structures the loadings shall be assumed working on1.5 times the projected area of members on one face. The wind load to be applied in the designshall be 765 N/m², on all surfaces except for cylindrical objects where 430 N/m² shall be applied.

24.6.2.2 Vertical Lo ading s

The weight of actual conductors, insulators and apparatus to be installed, must be obtained fromrelevant suppliers, and/or the designers of the substation. Dead weights shall not be increased






by the factory of safety in design calculations.

24.6.2.3 Condu ctor Tensions

Tension in conductors (and earth wires) acting on busbar gantries and other structures shall be in

accordance with the Sag and Tensions Charts produced as part of the design process.24.6.2.4 Lin e Gantri es

Transmission lines are terminated on special towers outside the substation fence. The slackspans from terminal towers to line gantries will cause forces acting upon the line gantries asshown in the table below.

The transversal forces in the design allows for an angle +/- 30° from perpendicular to the linegantry.

A vertical angle of +/- 20° is also allowed for.

Mechanical loads on line gantries, caused by slack spans from terminal towers:

TYPE OF FORCES(In Newtons/phase)

TYPE OF INCOMING LINE

132 kV LINE 132 kV COMPACT LINE

Conductors2 x ACSR-Wolf/Lynx

EarthwireOPGW/GSW

7x3.25

Conductors1 x ACSR-Wolf/Lynx

EarthwireOPGW/GSW

7 x 3.25

Longitudinally 8,000 2,700 8,000 2, 700

Vertically 3,000 600 3000 600

Transversal 4,700 1,600 4, 700 1, 600

Note: For standardisation purposes the loads on gantries in 132kV line bays shall be made uniform.

24.6.2.5 Design Temp eratures

The structures shall be designed for the following temperatures:

Minimum ambient temp.

Maximum ambient temp.

Minimum conductor temp.

Maximum conductor temp.

24.6.2.6 Safety Factor s

The safety factors to be used for design are:

Item Factor based on Normal LoadExceptional Load

(short circuit load)

Steel Structures Yield Point 2.0 1.5

Tubular busses Yield Point 1.5 1.0

Foundations againstoverturning or uprooting

- 2.0 1.5

24.6.3 Electrical Clearances

Electrical clearances are given under Sub-chapter 3.6.2.






24.6.4 Phase Spacing

See main dimensions below.

24.6.5 Shield Angle

The shield angle of earth wires is given under the specification for switchgear.

24.6.6 Steel Structures, main dimensions

The main dimensions of the gantries are indicated on the table following where:

H1 = Height from top foundation to centre of girder

H2 = Height of earthing peak from centre of girder

L1 = Length of girder pylons

L2 = Length from centre of pylon to outer phase attachment

P = Phase spacing, distance between attachment points

Type Of StructureMain Dimensions (m) Remarks

H1 H2 L1 L2 P

132 kV:

Line gantry 11,5 10-15 12 3 3

Flying busbar gantry 11,5 10-15 12 3 3

Main busbar gantry 8 N/A 12 3 3

33 kV:

Line gantry 8 N/A 6 1,5 1,5

Flying busbar gantry 8 N/A 6 1,5 1,5

Main busbar gantry 5,5 N/A 6 1,5 1,5

11 kV:

Line gantry 8 N/A 6 1,5 1,5

Flying busbar gantry 8 N/A 6 1,5 1,5

Main busbar gantry 5,5 N/A 6 1,5 1,5

Note 1 : H2 dimensions will depend on the earthing coverage or protection needed and may thus vary from

one substation to another.Note 2 : These dimensions are for Tendering purposes only. Final dimensions will depend on theContractor’s approved design.

24.7 Design Requirements for Steel Structures

24.7.1 Steel Characteristics

All rolled steel sections, flats, plates and bolt and nut bars used shall consist of steelmanufactured by the open hearth or other approved process.

The steel shall comply in quality and strength at least with structural steel St 37-2 according toDIN 17100 or to Grade 43A according to BS 4360. If a steel of higher tensile grade is offered theappropriate Specification which details both mechanical and chemical properties shall beprovided. The steel shall be free from blisters, scales, laminations or other defects. Steel sections






shall be chosen with a view to avoiding delays in obtaining material.

All bolts shall be made of one type of steel only.

The steel shall be of a quality that will not have its physical properties changed, not becomeembrittled by hot-dip galvanising.

24.7.2 Design Stresses

24.7.2.1 Compression

The maximum ultimate stresses for compression members shall be calculated in accordance withECCS- “Manual on Stability of Steel Structures”, dated 1976, sub chapter 9 .2.

The basic buckling curve – non dimensional- for 90 o angles shall be:

222 2.2/4.4 cr

where

21.12.021.00.1

, E

R

L

cr = critical stress

= yield stress, actual or conventional

E= 210000N/mm 2

L= buckling length

R= radius of gyration

For less than 0.2 is cr

The basic bulking curve takes into account residual stresses and an initial crookedness 0.0015L.

For eccentrically loaded angles (i.e. angles connected in one leg only as diagonals or webmembers in lattice trusses) the buckling strength shall be calculated from the basic bucklingcurve using a modified non dimensional slenderness ration obtained from geometrical one A asfollows:

for 2 , 57.060.0

for 2 ,

The width to thickness relationship of the angle flanges shall be within the limit

15t

b

24.7.2.2 Tension, Bendin g, Shearing and Bearing

When the material thickness does not exceed 16mm, the ultimate stresses are to be based onthe upper yield point (Fy) of the material as follows:






Ultimate tension Fy

Ultimate bending Fy

Ultimate shearing 0.16 Fy

Ultimate bearing 1.8 Fy

For material over 16mm thick, the calculations shall be based on the lower yield point.

Tension and shearing stresses shall be calculated employing the net area of the structuremember shown below:

Stress Remarks Net section

Compression F

Tension

General F – dF

Angle, connected with only one bolt Fweb-dF

Angle, connected at one leg only with 2 or more bolts 0,9 (F-dF)

Shear Fweb-dF

F = Cross section area of member

DF = Sum of sectional areas of holes in themost unfavourable cross-section.

Fweb = Sectional area of determinative webcross section, bordering Flanges shall beneglected.

24.7.2.3 Lim iting Requirements for Dimension of Members and Bo lts

Maximum Slenderness Ratios:

The ratio between the unsupported length of a member and the relevant radius ofgyration (L/R) shall not exceed the following values:

Main members 150

Braces and all other members carryingcalculated stress 200

Tension and redundant members 250

Bolts and Bolted Joints

All metal parts shall preferably be secured by means of bolts and nuts and singlewashers. Welding may be permitted if the Contractor can prove that the quality issatisfactory. Foot plates will have to be welded on to main members.

Bolted joints shall be calculated as bearing – type connections, and no allowance forfrictional resistance shall be made. The minimum bolt size is M 12.

No bolt hole shall be more than 1.5mm larger than the corresponding bolt diameter. As faras possible, bolt head rather than nuts shall be on the outer or upper side faces ofstructure joints.






All bolts and nuts shall comply with BS 4190 or other equivalent standard and screwthreads shall be to the Metrical Standards. Bolts and nuts shall be of steel with hexagonalheads. Bolts of any given diameter shall be of one grade of steel and marked foridentification. Screw threads shall not form part of the shearing plane between members.

When in position all bolts or screwed rods shall project through the corresponding nutswith a minimum of 2.5mm and a maximum of 10mm.

The total thickness of the washers shall not be more than 0,6 x the bolt diameter.

Minimum distances for bolted joints:

Bolt(mm)

Min.width ofSection (mm)

Min. distance fromhole centre to edge

(mm)

Min. distancebetween holes

(mm)

M12 35 20(27) 30(54)

M16 45 25(35) 40(70)

M20 60 30(43) 50(86)

Values in parenthesis are only concerning parts, being stressed by tension, of the verticalframework of the girders as well as for pylon member joints.

Maximum distance between holes is 6 x d. (d = bolt diameter)

The distance from the centre of a bolt to the face of the outstanding flange of an angle onother members shall be such as to permit the use of a socket wrench when tightening thenut.

All bolts and threaded rods shall be galvanised, including the threaded portions; all nutsshall be galvanised with the exception of the threads, which shall be oiled. Galvanisingshall be in accordance with the Specification.

Where spring washers are used, these shall comply with BS 4464 or equivalent standard.

Punching will be allowed for locking the nuts.

All bolts, nuts and washers shall be furnished in excess of the actual number required tocompensate for normal field losses.

24.7.2.4 Redun dant Memb ers

Redundant members supporting pylon members or supporting other members shall be designedfor a transversal load at each node point of minimum 1.7% of the maximum load in the legmember or the other member respectively.

24.7.3 Detailing Requirements

24.7.3.1 Memb er Thick ness

The material used for the gantry girders and pylons members shall not be less than 4mm thick formembers carrying calculated stress.

24.7.3.2 Splices

Splices in all members shall be of the butt-splice or lap-splice type.

Splices of the main members shall be located immediately above horizontal members or diagonalbrace connection.

Only one splice per member shall be allowed.

24.7.3.3 Attachm ent of Insulator Strings






the Project Manager ’s consent in writing. After the straightening and bending the structure shallbe carefully examined.

24.8.3.2 Cutting

Cutting of parts shall be made so as not to cause any notches diminishing the strength or anydetrimental stresses. Cutting of section bars shall be made so that deformations are avoided.

24.8.3.3 Bo lt Holes

Besides by drilling, bolt holes may be punched if the thickness of the material does not exceed12mm and the diameter of the hole is not inferior to the thickness of the material.

In other cases, the holes shall be either drilled or sub-punched and thereafter reamed or drilled.The diameter of the die for sub-punching of holes shall be at least 2mm smaller than the nominaldiameter of the hole.

The punching shall be done by pressing, not by hitting the punch shall fit closely to the die. Theholes shall be straight and smooth with a clean surface. The outside dimensions of the materialto be punched must not alter and the materials not bend. Burrs shall be removed. Incorrect holesmay be neither partly nor wholly filled out by welding.

24.8.4 Welding

24.8.4.1 Qualifications for Executing the Welding Work

The welding work on the structures, if employed, shall be performed with a labour managementexperienced in welding and with skilled welders. The qualifications shall be testified by acertificate.

24.8.4.2 Execution of the Welding Work

The sequence of welding shall be such as to cause as small deformations and welding stressesas possible.

The welding shall be performed with equipment and in premises suitable for the purpose.

Equipment shall be well suited to the type of weld to be performed so that the right quality shallbe attained.

No gaps or hollows may appear in the welding into which acid may penetrate during the picklingprocedure preceding galvanising.

The weld shall be ground flush to the surface in such places where the welding bulge prevents aperfect fitting of components together.

A high bulge or uneven weld surface may be levelled out by chiselling or grinding.

24.8.4.3 Filler Metals for Weldin g

Standard filter metals shall be used and the strength class and quality shall be chosen tocorrespond to the base material.

24.8.5 Numbering of Parts

All separate parts of structures shall be marked with the part identification number which consistsof the following numbers:

Structure type number

The running number of the part in question.The marking shall be stamped onto the part before hot dip galvanising using numbers not lessthan 12mm high. The marking shall be placed near one end in the same relative position on






each part. The marking shall be clearly visible after galvanising and be located on the outside ofthe structure and so that they also are visible after erection.

24.8.6 Galvanising

All structure parts and components shall be hot dip galvanised in accordance with BS 729 orother appropriate standards and Sub-chapter 3.33.

The minimum coating mass on any individual component shall be 610 g/m².

Bolts, nuts and washers shall have a zinc coating not less than 305 g/m². (equal to 43mmthickness) when galvanized according to BS 729.

The nut threads shall be cut after hot tip galvanising and thinly oiled in order to protect thethreads during storage.

The zinc coating on bolt threads shall be so smooth and free from blisters, drops and projectionsthat nuts can be screwed on with fingers. It is prohibited to open bolt threads by cutting after hotdip galvanising.

Galvanising of steel counterpoise cable and other rods not exceeding 7mm diameter shall be inaccordance with BS 443 or other approved standard.

Galvanising defects shall be repaired as separately agreed upon with the Employer or the ProjectManager. Minor galvanising defects may, however, be patched by painting over with zincpowder paint. After galvanising, parts of a structure must not be welded, machined or bent. TheContractor shall at his own expense open all bolt holes where zinc has stuck so that theyconform to the aforementioned requirements.

The preparation of galvanising and the galvanising itself shall not adversely affect the mechanicalproperties of the coated material.

24.8.7 Packing, Storing and TransportIt shall be the Contractor’s responsibility to pack, store and transport all material so that theirphysical properties do not deteriorate.

Every delivery shall contain a complete material list, a copy of which shall be sent in advance tothe Employer or the Project Manager.

The costs for packing, storing, handling, transportation and customs and taxes shall be includedin the Tender price.

24.8.8 Test Program

Before starting the manufacture an inspection plan written by the Contractor showing the different

inspection procedures shall be mutually agreed between the Contractor and the Employer or theProject Manager.

The Contractor shall keep the Employer or the Project Manager informed about the course ofmanufacture of materials and works, so that the inspection and testing can be informed in thepresent of the Employer’s or the Project Manager ’s representative.

Before every inspection and test supervised by the Employer or the Project Manager theContractor shall satisfy himself that the work is in all respects in accordance with the specificationready for inspection and testing.

Routine tests shall be performed in accordance with the relevant standards and according toinstructions by the Employer or the Project Manager.

Representative samples, selected at random, of all materials amongst lots ready for despatch,shall be subject to tests in order to verify their conformity with the specification.

The tests shall be performed by the Contractor or his sub-Contractors, and the costs are deemedto be included in relevant prices in the Bill of Quantity.






Full and complete testing of all components shall be carried out to the satisfaction of theEmployer or the Project Manager.

All test results shall be documented in test reports which shall be delivered in triplicate to theEmployer or the Project Manager within 2 weeks after the tests have been carried out.

24.8.8.1 Shop Ass embly

One complete structure of each of the main structures (gantries) shall be manufactured for shopassembly and erected in the presence of the Employer or the Project Manager if he so requires.The Employer or the Project Manager will check the component parts for proper fit and ease ofassembly. Any defects shall be amended to the satisfaction of the Employer or the ProjectManager, before commencement of delivery.

24.8.8.2 Testing of Mechanical and Chemical Properties of Structur e Members

Steel samples shall be taken at random amongst lots of completely galvanised structuremembers. These samples shall be dimensioned and tested in accordance with DIN 17100 or BS

4360 or with other equivalent and approved standards.

24.8.8.3 Galvanisation Tests on Structur e Members, Bo lts and Nuts

The uniformity of the zinc coating on galvanised steel articles other than wires shall be tested asspecified in VDE 0210/5.69, Part IV or BS 729 Part 1.

24.8.8.4 Welded Tests

Welding tests shall be carried out in accordance with approved standards and as directed by theEmployer or the Project Manager.



SECTION IV: TECHNICAL SPECIFICATIONS

25. MV CABLES



Volume II – Section VI: Employer’s Requirements: Contract 16 - 132/33 kV & 33/11kV Substations

Chapter 2: 66, 33 and 33 kV cables


TABLE OF CONTENTS

25 66,33& 11 kV cables ........................................................................... 1

25.1 General .......................................................................................................... 1

25.2 Conductors ................................................................................................... 1

25.3 Cable ............................................................................................................. 1

25.3.1 Laying-up and Fillers of Three Phase Cables ......... .......... ......... ......... ......... .. 1

25.3.2 Manufacturer’s Identification .......................................................................... 1

25.3.3 Amour ............................................................................................................... 2

25.4 Testing .......................................................................................................... 2

25.5 Sealing and drumming ................................................................................. 2

25.6

Current carrying Capacity and Design Parameters ............. ............. ......... 2

25.7 Terminations ................................................................................................. 2

25.8 Heat Shrink Materials ................................................................................... 3

25.9 Installation .................................................................................................... 3

25.9.1 General ............................................................................................................. 3

25.9.2 Cable Marker .................................................................................................... 3

25.10 Excavation of Trenches ............................................................................... 3

25.10.1 Joint Holes ....................................................................................................... 4

25.10.2 Backfilling of Trenches ................................................................................... 4 25.11 Pavement Reinstating .................................................................................. 4

25.12 Ducts ............................................................................................................. 4

25.13 Galleries ........................................................................................................ 5

25.14 Parallel Separation ....................................................................................... 6

25.14.1 Low Voltage Cables ......................................................................................... 6

25.14.2 Medium Voltage Cables ......... .......... ......... ......... ......... .......... ......... ......... ........ 6

25.14.3 Telecommunication Cables ............................................................................ 6

25.14.4 Water Steam etc. ......... ......... ......... .......... ......... ......... ......... .......... ......... ......... .. 6

25.14.5 Oil Pipe Lines ................................................................................................... 6

25.14.6 Sewers .............................................................................................................. 6

25.14.7 Fuel Storage Tanks ......................................................................................... 6

25.14.8 Foundations of Other Services ......... ......... .......... ......... ......... ......... ......... ....... 6

25.15 Crossing of Roads and Railroad Tracks .................................................... 7

25.15.1 Public Roads .................................................................................................... 7

25.15.2 Railroad tracks................................................................................................. 7

25.16 Crossing Other Services.............................................................................. 7

25.16.1 Low Voltage Cables ......................................................................................... 7






25.16.2 Medium Voltage Cables ......... .......... ......... ......... ......... .......... ......... ......... ........ 7

25.16.3 Telecommunication Wires .............................................................................. 7

25.16.4 Water Steam etc. ......... ......... ......... .......... ......... ......... ......... .......... ......... ......... .. 7

25.16.5 Gas ................................................................................................................... 8

25.16.6 Sewers .............................................................................................................. 8

25.16.7 Fuel Depots ...................................................................................................... 8

25.17 Transporting Cable Drums .......................................................................... 8

25.18 Laying of the Cable ...................................................................................... 8

25.19 Mechanical Protection ................................................................................. 9

25.20 Warning Signs .............................................................................................. 9

25.20.1 Identification .................................................................................................... 9

25.20.2 Additional Requirements ................................................................................ 9






25 66, 33& 11 kV cables

25.1 General

This Chapter covers the technical requirements of 66, 33 and 11kV cables for installation andoperation in 66kV and above for outdoor switchyards.

The cables and accessories shall conform in general to latest IEC standards and ISOrecommendations except to the extent explicitly modified in this specification. The cablemanufacturer shall guarantee the maximum value of the overvoltage factor and all other electricalvalues according to IEC. The ratings and characteristics of the cables are described in Sub-chapter 25.2 .

All cables shall be suitable for operation: on a system with direct earthing of the transformer neutral under maximum load (ONAF conditions) plus 10 % specified for respective

transformers in the climatic conditions prevailing at site

No joints shall be allowed. Only dry vulcanising processes shall be used. Special precautionsshall be taken to avoid ingress and spreading of moisture and development of water-treeing. TheTenderers shall documents the construction measures used to achieve these requirements.

25.2 Conductors All conductors shall be stranded copper or aluminium. The conductor shall be clean, uniform insize, shape and quality, smooth and free from scale, splits, sharp edges and other harmfuldefects. The conductor shall be in accordance with IEC 60228. The conductor shall be filled withswelling powder to stop axial ingress of moisture.

25.3 CableThe conductor shall be covered with:

An extruded semi-conducting layer A layer of dry vulcanised cross-linked polyethylene (XLPE) insulation An extruded strippable semi-conducting layer A water tight copper or aluminium seal A layer of swelling tape to prevent axial ingress of water along the screen A layer of earthing screen of stranded aluminium or copper An outer LDPE (low density polyethylene) sheath for water tightness and

mechanical protection.

25.3.1 Laying-up and Fillers of Three Phase CablesThe cores of three-phase cable shall be laid-up together with suitable fillers, wormed circular andbinding tapes applied overall

25.3.2 Manufacturer’s Identification The manufacturer’s identification shall be provided throughout the length of the cables by meansof a tape u nder the sheath printed with the manufacturer’s name and ``Property of K ETRACO´.

Alternatively the identification may be embossed on the outer PVC sheet together withidentification and voltage markings






25.8 Heat Shrink MaterialsHeat shrinking tubing and moulded parts shall be flexible, flame retardant, polyofin-based materialof electrical insulating quality, and shall be obtained from an approved manufacturer. They shallbe suitable for use indoors or outdoors in the conditions prevailing on site

The material shall reduce to predetermined size and shape when heated above 120 °C. The

components shall also be provided with an internal coating of hot melt adhesive compound thatshall not flow or exude at temperature below 85 °C. All parts and materials shall be tested to aprogram of tests to be agreed with the manufacturer.

Each part shall bear the manufacturer’s mark, part number and any other necessary marking toensure correct identification for use on the correct size and type of cable. Each set of parts shallbe packed as one unit with full and complete installation instruction and clearly marked to showthe application.

25.9 InstallationThis extract from KPLC’s “Medium Voltage Undergroun d Distribution Handbook determines theminimum acceptable conditions for installation of medium voltage cables.”

25.9.1 GeneralThe cables will be laid in trenches that will be as straight as possible avoiding sharp bends.

The areas where trenches are to be excavated will be marked clearly on the ground. If thelocation of other services is known, they will be marked in order to take necessary precautions.

Before construction commences trial pits will be made in order to confirm the soil strata of theplanned trenches and to confirm the location of other services.

Safety precautions such as covering the trench, fencing and warning signs will have to beprovided for during the period of work.

When designing the plan for the trench layout, the minimum radius will be as in the followingtable.

TABLE 3.1: BENDING RADIIBending radii Single core 3-coreRecommended 17xD 15xDMinimum 15xD 12xD

At sealing ends 12xD 10xD

D = cable diameter

25.9.2 Cable MarkerCable markers shall be installed at the beginning and end of the cable run on the surface all alongthe route, at all changes of direction, and above all joints, above cable duct entries and exits andat an interval not exceeding 50m along the cable route. This information as well as details aboutthe joint (i.e. joint location) will be also recorded on a map.

25.10 Excavation of TrenchesThe trench will be dug vertically to a minimum depth of 600mm or more as required.






All precautions must be made so as not to cover any services e.g. fire hydrants with soil that maybe encountered in the path of the trench.

During construction on public roads passage and access of motorists and pedestrians tocommercial areas must be maintained.

In order to reduce the cost of reinstatement on roads and pavements the digging shall be done atintervals of 2-3 m and a gallery or tunnel dug underneath.

If trenches are constructed in soggy or inconsistent soil, the cables will be laid inside a duct as aprotective measure and precautions taken to prevent the entry of water at the ends or joints of theducts

The bottom of the trench must be made of firm material in order to prevent collapse of the basethat may subject the cable to mechanical stress.

When several cables of different voltages are laid in the same trench they will be placed atdifferent depths. The cables of the higher voltage will be placed deepest.

Where the trench is too deep as to cause instability to the walls of the trench shoring will beplaced to provide lateral support to the trench walls.

The separation between two groups of cables will be a minimum of 250mm. If this separationcannot be attained they will be laid in ducts or will be separated by a layer of bricks.

25.10.1 Joint HolesWhere cable joints are required to be made in the course of a cable run, a joint hole shall beexcavated of sufficient size to enable the cable jointer to work efficiently and unimpeded.

25.10.2 Backfilling of TrenchesOnce the cable has been laid the trenches must be back filled to an adequate compaction level.Care must be taken to ensure that the first layer covering the cables will be free of rocks or anysharp mechanical objects.

The back fill will be laid in layers of 150mm, which should be compressed and watered ifnecessary in order to make the soil sufficiently compact.

25.11 Pavement Reinstating

The pavement shall be reinstated back to the standard of the original pavement. New materialswill generally be used in accordance with Municipal regulations.

25.12 Ducts

Road crossings when necessary will be done with ducts in the following manner

they will be installed in a level position and concreted where possible toprovide mechanical protection throughout its length, they will have a depth of1.2m.

future expansion will be provided for by providing one or several spare ductsdepending on the location of the crossing.

at all times the cables should be adequately protected. road and railway crossings must be planned in full detail.






drainage of the trenches must be provided for during and after construction.

In crossings with other normal underground services, a prudent distance will be maintained inview of future excavations, and when there is a possibility of service interference, as is the caseof other electric cables, waste water sewers etc.

The ducts will be fabricated from PVC or concrete with a smooth interior surface and an interiordiameter of not less than 2 times the diameter of the cable to be housed inside it, and in no casewill this diameter be less than 150 mm.

The joints of ducts will be sealed with cement, in which case the bottom of the trench must becarefully levelled after setting down a layer of fine sand or red soil in order to permit continuous

joints.

The ducts will be laid in such a manner that there is no abrasion between the insulation of thecable and the surface of the duct.

In the cases of single core cables the cable will have to be anchored to prevent movement due to

magnetic effects by concreting the ducts at the ends of the joints. This shall not apply to threecore cables.

When constructing a duct a length of wire will be left inside to facilitate the fitting of cleaningelements as well as the cables themselves.

The cleaning will consist of passing inside a cylinder in order to remove concrete that will passthrough the joints and later passing a broom or a rag to remove the residue.

25.5.1.1 Direct Burial

For armoured cables the following criteria for burial will be met:

the trench must have a 150mm layer of fine sand upon which the cable shallbe laid to protect the cable from mechanical damage due to sharp objects. Ontop of the cable another 150mm of fine sand will be laid. Both layers will coverthe entire width of the trench.

the sand should be well graded any materials used for back filling the trench must meet the approval of the

Project Manager Construction Supervisor in charge. the cables must be buried at a depth of not less than 600mm. Exceptions

could be made for rocky areas where the minimum depth cannot be attained inthis case the cable will be laid in a duct.

Cables must be protected with a layer of protecting slabs, which will also indicate their presence.

For armoured cables the excavated materials without mechanically sharp objects will be adequateenough to backfill the trench.

Cables shall not be buried in areas within the substation boundaries. Necessary cable trenchesshall be prepared instead to the satisfaction of the client’s project Manager.

25.13 GalleriesWhen the numbers of cables justify the use they shall be laid in galleries.

The cables will be fixed to the cable trays by means of brackets or clamps.






All metallic elements will be earthed with independent connectors if there are circuits of differentvoltages.

Electric cables will not be installed where there are inflammable materials.

25.14 Parallel Separation

25.14.1 Low Voltage CablesMedium Voltage cables may be laid parallel to Low voltage cables as long as there is always aminimum distance of 250 mm between them. When this distance cannot be attained, a solid brickwall shall separate them or they will be placed in ducts.

25.14.2 Medium Voltage CablesThe distance to be maintained in the case of parallel situations of underground Medium Voltagelines is 250mm. If this distance cannot be achieved a protective brick wall will be installedbetween them, or one of them will be installed within ducts.

25.14.3 Telecommunication CablesIn the case of parallel laying of subterranean electric cables and telecommunications wires, theymust be as far as possible from each other. As long as the cables both electric andtelecommunications are buried, a minimum separation of 2 meters must be maintained at alltimes. This distance could be reduced further to 250mm between ducts.

The clearances must be in accordance with agreements between KPLC and KPTC

25.14.4 Water Steam etc.

In parallel layouts between power cables and buried water pipes a minimum distance of 0.5m willbe maintained in a horizontal projection. If these clearances cannot be maintained the cables willbe laid in ducts.

25.14.5 Oil Pipe LinesThe minimum distance between the cables and the oil pipelines will be 0.5 m. The cable will beprotected from any gas leaks.

25.14.6 SewersIn parallel layouts of electric cables with sewerage conduits, a minimum distance of 0.5 m will bemaintained, the cables will be adequately protected if this distance cannot be maintained.

25.14.7 Fuel Storage TanksThere will be a minimum distance of 1.20 meters between cables and fuel storage tanks, apartfrom providing adequate protection for the electric cables.

25.14.8 Foundations of Other Services

When there are structural supports for public transport, suspended telecommunication wires,street lighting, the electric cables will be laid at a distance of at least 500mm from the outerextremities of the supports or foundations of the structures. This minimum distance shall further






be increased to 1.5m if the support or foundation is subject to continuous stress towards the curbsides.

If this separation cannot be maintained a resistant mechanical safety measure must be usedthroughout the length of the support and its foundation, extending to a length of 500mm, on bothsides of outer extremes.

25.15 Crossing of Roads and Railroad Tracks

25.15.1 Public RoadsWhen crossing streets and roads cables must be laid at depths of at least 1.2m. The ducts mustbe durable and mechanically strong, and must have a minimum diameter of 150mm in order topermit the easy passage of the cables within the tubes. Conditions specified in the Electric Power

Act must be observed at all times. Spare ducts must be provided where necessary.

25.15.2 Railroad tracks

Crossing railroad tracks must be done with conduits laid perpendicular to the tracks at a minimumdepth of 1.6 m. This depth must be measured from the bottom side of the track’s crossbars. It isrecommended that the crossing takes place at the narrower points of railroad areas. Conditionsspecified by municipalities and the Railroad companies shall take precedence.

25.16 Crossing Other Services

25.16.1 Low Voltage CablesWhen medium voltage cables cross low voltage cables, a minimum distance of 250mm must bekept between them. If this cannot be achieved, medium voltage and low voltage cables must beseparated by pipes, conduits, or solid brick divisor walls.

25.16.2 Medium Voltage CablesWhen crossing other medium voltage cables, the minimum distance to be observed betweenthem is 250mm. If this distance cannot be maintained solid bricks must be laid between them.

25.16.3 Telecommunication WiresWhen crossing telecommunication wires, the electric cables must be situated within conduits ofappropriate mechanical resistance, maintaining a minimum distance of at least 250mm, betweenthe outer sides.

The electric cable must be protected in PVC or concrete duct and in such a way that it guaranteesthat the distance between the cables is greater than the minimum established for parallel layouts.

The crossing must be at least 1m from a junction box for telecommunications wires and joints forelectric cables will not be installed next to crossings of telecommunications cables.

25.16.4 Water Steam etc.There should never be a water pipe joint over the cable. A water pipe joint must be at least 2.0 m

from a crossing.






25.16.5 GasThe minimum distance in crossings with gas pipelines shall be of 250mm. The crossing shall notbe made over gas pipelines joints.

25.16.6 Sewers

In crossing sewage pipes it is recommended that the electric cable should be above the sewerline where possible.

25.16.7 Fuel DepotsElectric cable crossings over fuel deposits will be avoided at all times, the electric cables must belaid bordering the fuel tanks, maintaining a minimum distance of 1.2 metres.

25.17 Transporting Cable DrumsLoading and unloading from trucks or appropriate trailers will always be made through anadequate bar that passes through the centre of the cable drum.

The cable drums will always be transported upright and never on its side.

When several cable drums are transported together they must be aligned back to back and havestopping blocks to prevent movement.

The stoppers should be uniform so that they do not pierce the cable insulation. The stoppersshould span the whole length of the cable drum.

An alternative to stoppers may be to have wooden pieces nailed to the platform supporting cabledrums. The stoppers will be placed at the reels of the cable drums.

The cable drum must not be tied down with ropes, cables or chains. Upon offloading the cabledrum the roll must not drop down from the truck or trailer, a provisional ramp with an inclination ofnot more than 1/4 will instead be constructed in the case where there are no pulleys for lifting thedrum. The roll can be rolled of the ramp by means of guide ropes. Sand can be placed at thebottom of the ramp to act as shock absorber and brake for the cable drum.

When rolling the drum on the ground the rotational direction must be observed so that the cabledoes not come loose.

When the drum is rolled care must be taken to ensure that the drum is not rolled on rough ground.Care must also be taken to ensure the reel is not broken because the splinters can puncture the

cable.

Where possible the cable drums should not be exposed to the elements.

25.18 Laying of the CableThe cable drum will be installed on the site in such a way that the cable is reeled out of the toppart of the drum and is not forced when the cable is laid.

During cable laying the drum will always be supported by means of a mechanical jack and a barof the appropriate strength.

The base of the jacks will be sufficiently large as to ensure stability during operation.






When taking off the wood stoppers care must ensure that the material used in nailing them doesno damage to the cable.

The cables must always be unrolled and laid with the greatest care to avoid torsion or kinks andalways maintaining the correct bending radius of the cables (ref: 3.1)

When the cables are being laid the workers must be distributed uniformly along the trench.

The cables should also be laid using cable rollers.

25.19 Mechanical ProtectionUnderground electric lines must be protected against possible breakdowns caused by landslides,contact with hard bodies, and clashing of metal tools. For this purpose, a protective layer of hatarislabs of class 15 concrete will be placed.

25.20 Warning Signs All cables must have a protection slab placed over the cables buried at least 200 mm above thecable layer. When the cables or groups of cables of different voltages are placed in vertical layersthe protection slab must be placed over each layer.

25.20.1 IdentificationThe cables must bear marks indicating the year of manufacture, manufacturer’s name, and cablecharacteristics (size and voltage level).

25.20.2 Additional Requirements

The cables shall additionally meet the following standards. Tenderers shall give technicaldocuments on whether they meet these standards.

Standards summaryTest carried on cables

Cable Test Type Applicable Standard1 Water Ingress Test IEEE 11382 Seepage of Flooding Compound IEEE 11383 Short Circuit Test IEEE 11384 Aeolian Vibration Test IEEE 11385 Galloping Test IEEE 11386 Sheave Test IEEE 11387 Crush Test IEEE 11388 Impact Test IEEE 11389 Creep Test IEEE 113810 Fibre Strain Test IEEE 113811 Strain Margin Test IEEE 113812 Stress Strain Test IEEE 113813 Cable Cut-Off Wavelength IEEE 113814 Temperature Cycle Test IEEE Std 56315 Cable Self Damping IEEE Std 416 Lightning Test EIA/TIA-455-16A17 Salt Spray Corrosion MCIT 048-200 6508

18 Temperature Cycling/Ageing/Water Immersion MCIT 048 200 6508






19 Tension Cycle Sustained Loading MCIT 048 200 650820 Gas Tube Tightness Test MCIT 048 200 650821 Twist Test MCIT 048 200 650822 Bend Test IEC 79423 DC Resistance25 Ageing Test EN187000


Refer to Sub-chapter 3.12 and individual equipment test specifications throughout theseEmployer’s Requirements.

All protection and supervisory control systems shall undergo testing as required by IECstandards.

Additionally, the Contractor shall prepare a comprehensive overall test program for the approvalof the Project manager and Employer.


If the technical requirements are not met or the performance of the equipment during test do notmeet the guarantees stated in the technical particulars subject to tolerances specified in relevantIEC Standards, the Employer shall have the right to reject the faulty component or the entire item.The Contractor shall replace the same in full compliance with the specification.

25.23 Technical Data SheetRefer to Chapter 26




26. TECHNICAL DATA SHEETS



Volume II – Section VI : Employer’s Requirements : Contract 16 - 132/33kV Substations and BaysChapter 26: Technical Data Sheets


26 TECHNICAL DATA SHEETS

The Bidder is required to fill in every Technical Data Sheet. The filled sheets shall beincluded in the Bid.

Improperly completed Technical Data Sheets may result in the Bid being rejected asprovided for in ITB Clause 30.

The Tendered Technical Data Sheets shall be bound into the Contract as technicalperformance guarantees.

TABLE of CONTENTS

26 TECHNICAL DATA SHEETS 1

DEFINITIONS AND ABBREVIATIONS 2 Table 1: 132/33 kV, 7.5 MVA Power Transformer and On-Load Tap Changer 3 Table 2: 132/11 kV 7.5 MVA Power Transformer – On load Tap changer 7 Table 3: 132 kV Circuit Breaker 10

Table 4: 132 kV Isolators with Earthing Switches 12 Table 5: 132 kV XLPE Cable 13 Table 6: 33kV Outdoor Circuit Breaker 17 Table 7: 33 kV Isolators with Earthing Switches 19 Table 8: 11kV Outdoor Circuit Breaker 20 Table 9: 11kV Isolators with Earthing Switches 22 Table 10: 132 kV Voltage Transformer 23 Table 11: 132kV Current Transformer 24 Table 12: 132kV Surge Arresters 25 Table 13: 33kV Voltage Transformer 26 Table 14: 33kV Current Transformer 27 Table 15: 33kV Surge Arresters 28 Table 16: 11kV Voltage Transformer 29 Table 17: 11kV Current Transformer 30 Table 18: 11kV Surge Arresters 31 Table 19: 132kV Dead-End and Suspension Insulators - Discs 32 Table 20: 132kV Post-Type Insulators 33 Table 21: 33/0.4kV Auxiliary Transformer 34 Table 22: Low Voltage AC Distribution Panel for Auxiliary Services 35 Table 23: Battery Bank 110 V DC, 300 Ah 36 Table 24: Battery Charger 37 Table 25: Protection Relays 39 Table 26: Telecommunication System 54

Table 27: Control and Monitoring System 56





Table 1: 132/33 kV, 7.5 MVA Power Transformer and On-Load Tap Changer

Minimum Requirements Data offered byBidderDescription Unit Data

Manufacturer to bespecified

Type 3-phase, oil-immersed,

with on-loadtap changer

Installation outdoorRated maximum voltage (Primary / Secondary) kV 145 / 36Rated service voltage

Primary side (high voltage) kV 132 Secondary side (low voltage) kV 33

Rated no-load voltage at rated frequency on:

HV, principal tapping kV to bespecified

HV, extreme plus tapping kV to bespecified

HV, extreme minus tapping kV to bespecified

LV kV to bespecified

Rated power ONAN[Performance Guarantee]

MVA 10

Rated frequency Hz 50Rated current

Primary side (high voltage) A to bespecified

Secondary side (low voltage) A to bespecified

Vector group Dyn1Impedance voltage of:

ONAN centre tap % 9.8Insulation uniformType of cooling ONAN

Tapping range ± 1.67%in ± 8 steps

No-load losses at rated frequency and 100% volt-age - maximum value [Performance Guarantee]

kW to bespecified

Load losses at rated frequency and 100% voltage(75°C) - maximum value: [Performance Guarantee]

ONAN kW to bespecified

ONAF kW to bespecified

Material of winding copper

Temperature rise at rated power over 40°C maxi-mum ambient [Performance Guarantee] oil (upper level) °C 55






winding °C 60Rated power frequency withstand voltage HV/LV kV 275/70Rated lightning impulse withstand voltage:

HV windings kV peak 650

LV windings kV peak 170

Short circuit impedance referred to the first windingin the following pairs: [Performance Guarantee]

At principal tap: high voltage - low voltage / phase to bespecified

At extreme plus tap: high voltage - lowvoltage

/ phase to bespecified

At extreme minus tap: high voltage - lowvoltage

/ phase to bespecified

Maximum noise level (Lp) [Performance Guarantee] dB (A) 70

Maximum no-load current % In 0.2Painting Admiralty

Grey shadeNo. 632 as

per BS 381CDimensions

length mm to bespecified

width mm to bespecified

height mm to bespecified

distance between wheels' centres mm to bespecified

Total weight kg to bespecified

Oil weight kg to bespecified

Applicable standard(s) IEC 60076IEC 60354

Transformer Bushings

Maximum current carrying capacity of bushings: HV A 120% of I N LV A 120% of I N

Rated service voltage of bushings: HV kV 132 LV kV 33 HV, neutral kV to be

specified LV, neutral kV to be

specified

1 minute, 50 Hz dry withstand voltage:






HV bushing kV to bespecified

LV bushing kV to bespecified

TV bushing kV to bespecified

HV, LV neutral bushings kV to bespecified

1 minute, 50 Hz wet withstand voltage: HV bushing kV to be

specified LV bushing kV to be

specified TV bushing kV to be

specified HV, LV neutral bushings kV to be

specified

Impulse withstand voltage: HV bushing kV to be

specified LV bushing kV to be

specified

On-Load Tap Changer

Manufacturer to bespecified

Type to bespecified

Rated current A 175Rated short-time current

1 second (maximum) kA 31.5 3 seconds kA to be

specified Step voltage V to be

specified

Number of steps 17On-load tap changer ±8 x 1.67%Minimum number of operations operations 200,000Motor drive

Type to bespecified

Supply voltage V 400/230 Insulation level voltage to earth kV rms to be

specifiedInsulation level

Voltage to earth kV rms to be

specified Impulse test voltage kV peak to bespecified






One-minute power frequency test voltage(50 Hz)

kV rms to bespecified

Internal insulation levels / one-minute power fre-quency test voltage:

between selected and pre-selected tap kV peak to bespecified


across fine tap winding kV peak to bespecified


between phases of fine tap winding kV peak to bespecified






Table 2: 132/11 kV 7.5 MVA Power Transformer – On load Tap changer


Manufacturer to be specifiedType 3-phase, oil-

immersed, withon-load tap

changerInstallation outdoorRated maximum voltage (Primary / Secondary) kV 145 / 11Rated service voltage

Primary side (high voltage) kV 132 Secondary side (low voltage) kV 11

Rated no-load voltage at rated frequency on:

HV, principal tapping kV to be specified HV, extreme plus tapping kV to be specified HV, extreme minus tapping kV to be specified LV kV to be specified

Rated power ONAN[Performance Guarantee]

MVA 10

Rated frequency Hz 50Rated current

Primary side (high voltage) A to be specified Secondary side (low voltage) A to be specified

Vector group Dyn1Impedance voltage of:

ONAN centre tap % 9.8Insulation uniformType of cooling ONANTapping range ± 1.67%

in ± 8 stepsNo-load losses at rated frequency and 100% volt-age - maximum value [Performance Guarantee]

kW to be specified

Load losses at rated frequency and 100% voltage(75°C) - maximum value: [Performance Guarantee]

ONAN kW to be specified

ONAF kW to be specifiedMaterial of winding copperTemperature rise at rated power over 40°C maxi-mum ambient [Performance Guarantee]

oil (upper level) °C 55 winding °C 60

Rated power frequency withstand voltage HV/LV kV 275/70Rated lightning impulse withstand voltage:

HV windings kV peak 650 LV windings kV peak 170

Short circuit impedance referred to the first windingin the following pairs: [Performance Guarantee]






At principal tap: high voltage - low voltage / phase to be specified At extreme plus tap: high voltage - low

voltage / phase to be specified

At extreme minus tap: high voltage - low

voltage

/ phase to be specified

Maximum noise level (Lp) [Performance Guarantee] dB (A) 70

Maximum no-load current % In 0.2Painting Admiralty Grey

shade No. 632as per BS

381CDimensions

length mm to be specified width mm to be specified height mm to be specified distance between wheels' centres mm to be specified

Total weight kg to be specifiedOil weight kg to be specified

Applicable standard(s) IEC 60076IEC 60354

Transformer Bushings

Maximum current carrying capacity of bushings: HV A 120% of I N LV A 120% of I N

Rated service voltage of bushings: HV kV 132 LV kV 11 HV, neutral kV to be specified LV, neutral kV to be specified

1 minute, 50 Hz dry withstand voltage: HV bushing kV to be specified LV bushing kV to be specified TV bushing kV to be specified

HV, LV neutral bushings kV to be specified

1 minute, 50 Hz wet withstand voltage: HV bushing kV to be specified LV bushing kV to be specified TV bushing kV to be specified HV, LV neutral bushings kV to be specified

Impulse withstand voltage: HV bushing kV to be specified LV bushing kV to be specified






On-Load Tap Changer

Manufacturer to be specifiedType to be specifiedRated current A 175

Rated short-time current 1 second (maximum) kA 31.5 3 seconds kA to be specified

Step voltage V to be specifiedNumber of steps 17On-load tap changer ±8 x 1.67%Minimum number of operations operations 200,000Motor drive

Type to be specified Supply voltage V 400/230 Insulation level voltage to earth kV rms to be specified

Insulation level Voltage to earth kV rms to be specified Impulse test voltage kV peak to be specified One-minute power frequency test voltage

(50 Hz)kV rms to be specified

Internal insulation levels / one-minute power fre-quency test voltage:

between selected and pre-selected tap kV peak to be specifiedkV rms to be specified

across fine tap winding kV peak to be specifiedkV rms to be specified

between phases of fine tap winding kV peak to be specifiedkV rms to be specified






-For closing

For opening

hydraulic

Closing and opening coil voltage V DC 110

Number of closing coils 1 Spring charging time s to be specified Manual spring release yes Hand operating facilty yes Mechanical Interlocking facility with isolators yes Emergency trip facility yes Mechanical On and OFF indicators yes Number of opening coils 2 Number of auxiliary contacts available 5 No., 5 NC

Main dimensions: Depth mm to be specified

Height mm to be specifiedWeight kg to be specified Accessories in the motor mech. enclosure

Operation counter yes Local manual control yes Test switches (dc) yes Heater yes

Weatherproof, corrosion resistance enclosure IP65 Accessories in the central control panel

Anti-pumping relay yes Local/distance command selector switch yes Local operation push buttons yes Minimum pressure lock-out and alarm relay yes Lighting, heating and service plug yes Terminal blocks yes Test switches (DC) yes Phase discrepancy timer relay yes Mounting brackets and hardware yes

With all necessary accessories for installation to be specified Applicable standard(s) IEC 62271-100





Table 4: 132 kV Isolators with Earthing Switches


Manufacturer to be specifiedType to be specified

Installation outdoorRated maximum voltage kV 145Rated service voltage kV 132Rated lightning impulse (BIL) (at altitude less than 1000 M) kV peak 650Power frequency withstand voltage (at altitude less than 1000 M) kV rms 275Rated short-time current kA 31.5Rated frequency Hz 50Number of poles 3Rated current A 1600Minimum creepage distance mm/kV 31Operation motorized

Opening time sec. ≤ 30 Closing time sec. ≤ 30 Rated peak withstand current kA 100Minimum clearance in air:

Between poles mm 1600

To earth mm 1300

For isolating distance mm to be specified

Type of operating mechanism: For disconnector motor

For earthing switch manual

Rated supply voltage for operating mechanism V DC 110Current required at rated supply voltage to operate isolator: A to be specifiedHand operating facility yesLocking arrangement in Off and On yes

Automatice isolation of control supplies when lock off yesRated power of operating coil WRated Motor power WFacing of terminals and contacts to be specifiedShape of terminals of the main circuit to be specifiedNumber and type of auxiliary switches:

Tin plated for Isolator Yes For the disconnector 5 NO , 5 NC

For the earth switch to be specified

Auxiliary contact rating A > 10Wind load Pa

(N/mm²)to be specified

Mechanical terminals load: Straight load N 500

Cross load N 170

Weight of complete disconnector: With earthing switch kg to be specified

Without earthing switch kg to be specified

Approximate dimensions in open position mm to be specified Approximate dimensions in close position mm to be specified

With all accessories for installation to be specified Applicable Standard(s) IEC 62271-102





Table 5: 132 kV XLPE CableMinimum Requirements Data offered by

BidderDescription Unit Data

Manufacturer to be specifiedLocation of manufacturing site to be specified

Manufacture quality certification ISO 9001Circuit rating required MVA 901.0 General description of cable Number of cores 1System voltage kV 132Conductor size mm 2 Insulation type XLPEMetal sheath type LeadOversheath type HDPE2.0 Insulation CordinationHighest system Voltage (Um) (Insulation class) kV 145

Nominal Voltage between conductors kV 132Rated frequency Hz 50Nominal Voltage between conductor and sheath (Uo) kV 76.2Rated Withstand impulse Voltage ( altitude < 1000 M) kV 650Rated short duration power frequency withstand voltage(altitude < 1000 M)

kV 275

3.0 Rating 1maximum continuous direct- buried current ratingassumingGround temperature of 30 o C, Max. Soil Thermalresistivity of 2.7Km/W, Flat formation configuration andspecial bonding of metal sheathGuaranteed current rating Single TrenchCalculation Method

A

To be specified

IEC 60840Maximum continuos in air current , assuming

Air Temperature (in shade) of 40 oC, Flat formationconfiguration spacing of 250mm, Thermally independentof other circuits and special bonding of metal sheathCalculation Method

ATo be specified

IEC 60840maximum permissible core temperature for continuosoperation

oC 90

Sort circuit capacity for 1 sec

Permissible Max. sheath TemperaturePermissible Max. Conductor Temperature

kA

oCoC

To be specified

Permissible emergency Overload Applied on 100% continuous load

Emergency current rating Max. Emergency temperature Allowable duration/ operation Allowable total duration/ operation

Max. average duration/average on total life of cable

AoC

HoursHoursHours

to be specified

Applied on 50% continuous load Emergency current rating Max. Emergency temperature Allowable duration/ operation

AoC

Hours

to be specified






Allowable total duration/ operationMax. average duration/average on total life of cable

HoursHours

Applied on 100% continuous load Emergency current rating

Max. Emergency temperature Allowable duration/ operation Allowable total duration/ operation

Max. average duration/average on total life of cable

Ao

CHoursHoursHours

to be specified

4.0 Construction features

Conductor Material Nominal cross section Shape and type of conductor Overall diameter Water blocking method Semi conductor blinder tape

mm 2

mmtape/yarn

yesConductor Screen

Material

Nominal Thickness Minimum Thickness Nominal overall diameter Compound identification reference

mmmmmm

Fully bondedSemicon. XLPE

yes

Insulation Material Nominal Thickness

Minimum Thickness Nominal overall diameter Max. Continuos operating temperature Compound identification reference

Maximum stress at nominal voltage At conductor screen At insulator screen

Maximum stress at impulse voltage At conductor screen At insulator screen

mm

mmmmoC

kV/mmkV/mm

kV/mmkV/mm

XLPE

90yes

Insulation screen

Material

Nominal Thickness Nominal overall diameter Compound identification reference Indelible ink marking on screen

mmmm

Fully bonded

Semicon. XLPE

yes

XLPE manufacturing methods Extrusion line type e,g CCv,MDCV,VCV Single pass/triple exclusion Curing method Cooling method Degassing period

days

VCVyesdrydry






Bedding for moisture absorption Type of Material

Nominal Thickness

Mimimum thickness Nominal overall diameter

mm

mmmm

Metallic screen Type and Material Nominal Thickness Mimimum thickness Nominal diameter over screen Cross sectional area of he screen Short time current density(1sec)

mmmmmmmm 2

kA/mm 2

Copper wire

Bedding/Binder tape Type and Material

Nominal Thickness Mimimum thickness Nominal overall diameter over bedding

mmmmmm

Metallic screen Type and Material Nominal Thickness Mimimum thickness Nominal diameter over screen Cross sectional area of he screen

Short time current density(1sec)

mmmmmmmm 2

kA/mm2

lead-alloy ½ C

Protective anti corrosion external sheath covering Bitumen undercoat Type and material Colour Nominal thickness Minimum thickness Termite resistant Type of anti termite protection Thermal resistivity Type of fire protection for closing section

mmmm

Km/w

HDPEBlack

YesSpecify max. 6.0

Type of conductive outer layer Graphite/orsemicon.polymer

Weight of completed cable Copper Insulation Lead alloy Gross weight

Kg/mKg/mKg/mKg/m

to be specified

5.0 losses

Maximum dielectric loss per meter/ phase when operatingat nominal voltage frequency and at maximum conductortemperature

W/m to be specified

Maximum sheath loss per meter/ phase when operatingat nominal voltage frequency and at current stipulated in

W/m to be specified






item 3 with sheath bonded and earthed as recommended(sectionalising Cross bonding)Maximum conductor loss per meter/ phase whenoperating at nominal voltage frequency and at current

stipulated in item 3

W/m to be specified

Total loss of cable per metre/ phase of three phase circuit W/m to be specified6.0 Electrical values

Maximum dc resistance of conductor at 20 o C µ Ω/m to be specifiedMaximum ac resistance of conductor at operatingtemperature C

µΩ/m to be specified

Equivalent reactance of three phase circuit µ Ω/m to be specifiedElectrostatic capacitance per conductor of cable atnominal voltage and operating temperature

pF/m to be specified

Max. charging current per conductor at nominal voltage mA/m to be specifiedCharging capacity of three phase system (at Uo) Var/m to be specifiedMax. dielectric loss factor of cable at nominal voltage andfrequency at a conductor temperature of;

20 oC 90 oC

to be specified

Positive and negative impedance Ω/m to be specifiedZero sequence impedance (as installed conditions)

Resistance Reactance Capacitance

Ω/m Ω/m

pF/m

to be specified

Surge impedance Ω/m to be specified7.0 Bonding and earthing

Type of special bondingMax. sheath potential of completed cable with conductorat max. earth fault current of 31.5 kA with sheath bondedand earthed as recommended

V/m to be specified

Max. sheath potential of completed cable with conductorat rated current with sheath bonded and earthed asrecommended

V/m to be specified

8.0 Testing

Routine tests As per IEC 60840 Additional tests specified in Ketraco spec.

yes

Sample tests

5Uo for 1 hr ( as per Ketraco spec)

IEC 60840

Type tests Test regime Location of test date of test

yes

Commissioning tests AC voltage withstand

Partial discharge monitoring Oversheath DC voltage test

kV

1.7Uo for 1 hour< 10pC

12kV for 15minutes





Table 6: 33kV Outdoor Circuit Breaker


Manufacturer to be specified

Type of circuit breaker outdoor typeType of arc quenching medium VacuumModel to be specifiedRated maximum voltage kV 36Rated service voltage kV 33Rated lightning impulse (BIL)(at altitude less than 1000 M)

kV peak 170

Power frequency withstand voltage(at altitude less than 1000 M)

kV rms 70

Rated frequency Hz 50Number of phases 3Rated currentIncomers and feedersBus coupler

A800

1200Short circuit breaking current kA 25

8.0 Short time withstand sec. 19.0 DC component time constant ms 45

Maximum breaking time ms 50Maximum closing time ms 120Related short circuit making current kA peak 62.5Number of tripping coils 2Number of closing coils 1Operating sequence - O - 0.3 s - CO -

3 min - CO Annual rate of gas leakage at normal pressure % ≤ 1%Minimum creepage distance mm/kV 25Operating mechanism

10.0 Type to be specified11.0 Motor voltage V DC 11012.0 Motor power rating13.0 Closing and opening coil voltage V DC 11014.0 Number of closing coils 115.0 Number of opening coils 216.0 Spring charge time s

17.0 Manual release spring yes

18.0 Hand operating facility yes

19.0 Emergency trip facility yes

20.0 Mechanical Off and On indicators yes

21.0 Number of auxiliary contactsavailable

5 No., 5 NC

Main dimensions:22.0 Depth mm to be specified23.0 Height mm to be specified

Weight kg to be specified Accessories in the motor mech. enclosure






24.0 Operation counter yes25.0 Local manual control yes26.0 Test switches (dc) yes27.0 Heater yes

Weatherproof, corrosion resistance enclosure IP65 Accessories in the central control panel

28.0 Anti-pumping relay yes29.0 Local/distance command selectorswitch

yes

30.0 Local operation push buttons yes31.0 Minimum pressure lock-out andalarm relay

yes

32.0 Lighting, heating and service plug yes33.0 Terminal blocks yes34.0 Test switches (DC) yes

35.0 Phase discrepancy timer relay yes36.0 Mounting brackets and hardware yesWith all necessary accessories for installation to be specified

Applicable standard(s) IEC 62271-100





Table 7: 33 kV Isolators with Earthing Switches



Installation outdoorRated maximum voltage kV 36Rated service voltage kV 33Rated lightning impulse (BIL) (at altitude less than 1000 M) kV peak 170Power frequency withstand voltage (at altitude less than 1000 M) kV rms 70

Rated short-time current kA 25Rated frequency Hz 50Number of poles 3Rated current A 800Hand operating facility yes

Locking arrangement in Off and On yesyes

Automatic isolation of control supplies when lock off yes yes

Rated power of operating coil WRated Motor power WMinimum creepage distance mm/kV 31Operation motorizedOpening time sec. ≤ 30 Closing time sec. ≤ 30 Rated peak withstand current kA 100Minimum clearance in air:

37.0 Between poles mm 50038.0 To earth mm 43539.0 For isolating distance mm to be specified

Type of operating mechanism:40.0 For disconnector Motorised

41.0 For earthing switch manual

Rated supply voltage for operating mechanism V DC 110Current required at rated supply voltage to operate isolator: A to be specifiedFacing of terminals and contacts to be specifiedShape of terminals of the main circuit to be specifiedNumber and type of auxiliary switches:

42.0 For the disconnector 5 NO , 5 NC

43.0 For the earth switch to be specified

Auxiliary contact rating A > 10Wind load Pa

(N/mm²)to be specified

Mechanical terminals load:44.0 Straight load N 500

45.0 Cross load N 170

Weight of complete disconnector:46.0 With earthing switch kg to be specified

47.0 Without earthing switch kg to be specified

Approximate dimensions in open position mm to be specified Approximate dimensions in close position mm to be specified

With all accessories for installation to be specified Applicable Standard(s) IEC 62271-102





Table 8: 11kV Outdoor Circuit Breaker


Manufacturer to be specifiedType of circuit breaker outdoor type

Type of arc quenching medium Vacuum / SF 6 Model to be specifiedRated maximum voltage kV 12

Rated service voltage kV 11Rated lightning impulse (BIL) kV peak 95

Power frequency withstand voltage kV rms 38

Internal arcingTest CertificateTesting instituteShort circuit current during the test :

Symmetrical component, rms value andduration, I th

Momentary peak value , i km Rated frequency Hz 50Number of phases 3Rated current A 630Short circuit breaking current kA 25

48.0 Short time withstand sec. 149.0 DC component time constant ms 45

Maximum breaking time ms 50Maximum closing time ms 120Related short circuit making current kA peak 62.5Number of tripping coils 2Number of closing coils 1Operating sequence - O - 0.3 s - CO -

3 min - CO Annual rate of gas leakage at normal pressure % ≤ 1%Minimum creepage distance mm/kV 25Operating mechanism

50.0 Type to be specified51.0 Motor voltage V DC 110

52.0 Closing and opening coil voltage V DC 11053.0 Number of closing coils 154.0 Number of opening coils 255.0 Number of auxiliary contactsavailable

5 No., 5 NC

Main dimensions:56.0 Depth mm to be specified57.0 Height mm to be specified

Weight kg to be specified Accessories in the motor mech. enclosure

58.0 Operation counter to be specified

59.0 Local manual control to be specified60.0 Test switches (dc) to be specified






61.0 Heater to be specifiedWeatherproof, corrosion resistance enclosure IP65

Accessories in the central control panel62.0 Anti-pumping relay yes

63.0 Local/distance command selectorswitch

yes

64.0 Local operation push buttons yes65.0 Minimum pressure lock-out andalarm relay

yes

66.0 Lighting, heating and service plug yes67.0 Terminal blocks yes68.0 Test switches (DC) yes69.0 Phase discrepancy timer relay yes70.0 Mounting brackets and hardware

With all necessary accessories for installation to be specified






Table 9: 11kV Isolators with Earthing Switches



Installation outdoorRated maximum voltage kV 12Rated service voltage kV 11Rated lightning impulse (BIL)(at altitude less than 1000 M)

kV peak 95


kV rms 38

Rated short-time current kA 25Rated frequency Hz 50Number of poles 3Rated current A 800Minimum creepage distance mm/kV 31Operation motorizedOpening time sec. ≤ 30 Closing time sec. ≤ 30 Rated peak withstand current kA 100Minimum clearance in air:

71.0 Between poles mm 50072.0 To earth mm 25073.0 For isolating distance mm to be specified

Type of operating mechanism:74.0 For disconnector Motorised

75.0 For earthing switch Manual

Rated supply voltage for operating mechanism V DC 110Current required at rated supply voltage to operateisolator:

A to be specified

Facing of terminals and contacts to be specifiedShape of terminals of the main circuit to be specifiedNumber and type of auxiliary switches:

76.0 For the disconnector 5 NO , 5 NC

77.0 For the earth switch to be specified

Auxiliary contact rating A > 10Wind load Pa (N/mm²) to be specifiedMechanical terminals load:

78.0 Straight load N 50079.0 Cross load N 170

Weight of complete disconnector:80.0 With earthing switch kg to be specified

81.0 Without earthing switch kg to be specified

Approximate dimensions in open position mm to be specified Approximate dimensions in close position mm to be specifiedWith all accessories for installation to be specified

Applicable Standard(s) IEC 62271-102





Table 12: 132kV Surge Arresters


Manufacturer's name to be indicatedType to be specified

Installation outdoorNominal system voltage kV 132Rated operating voltage (Ur) kV 108Rated continuous operating voltage (Uc) kV 84Rated frequency Hz 50Nominal discharge current kA 10Residual voltage for:

101.0 Lightning current 8/20 impulse kV to be specified102.0 Step current 1/20 impulse of 10 kA kV to be specified

Switching current 30/60 impulse of 500 A/1000 A kV to be specifiedHigh current 4/10 impulse withstand value kA 100

Low current, long duration current impulse with-stand (upper value) A 1000

Line discharge class 3 Absorption capability in kJ/kV of arrester rating atthermal stability

kJ/kV 8

Pressure relief class class ASuitability for fault current kA 40Power frequency 1 min. withstand voltage, wet (at

altitude less than 1000 M) kV 275

Maximum RIV at 1000 kHz measured at 1.05 timethe system highest voltage

micro V 500

Impulse withstand voltage of arrester insulationexternal assembly (at altitude less than 1000 M)

kV crest 650

Maximum short circuit rating kA 31.5Overall height of arrester mm to be specifiedCreepage distance mm/kV 31Weight of arrester kg to be specified

Arrester classification heavy duty,station-type

gapless metaloxide or

equivalent Accessories: 132 kV surge arrester discharge

counter103.0 Type outdoor104.0 Counter indication digital105.0 Protection class IP 54106.0 Number per 3 arresters 1

Applicable Standard(s) IEC 60099-1, 1A,2, 4





Table 13: 33kV Voltage Transformer



Model to be specifiedInstallation outdoorExecutionRated maximum voltage kV 36Rated primary voltage kV 33/√3 Rated secondary voltage (second winding) kV 0.1/√3 Rated secondary voltage (third winding) kV 0.1/√3 Rated frequency Hz 50Impulse withstand voltage 1.2/50 micro s wave(at altitude less than 1000 M)

kV peak 170


kV rms 70

Power frequency withstand voltage secondarywinding

kV rms 2

Rated output (second winding/ third winding): VA 100/100 Accuracy class

107.0 For metering 0.2108.0 For measuring 0.5109.0 For protection 3P

Voltage factor at rated voltage:110.0 Continuous 1.2111.0 30 second 1.5

Thermal limit burden VA to be specifiedNormal temperature rise: 28

112.0 Winding °C 50113.0 Oil °C 45

Maximum temperature rise under short circuit con-ditions:

114.0 Winding °C to be specified115.0 Oil °C to be specified

Total height mm to be specifiedMinimum creepage distance: mm/kv 31Size and section of terminals bolts mm to be specifiedWeight of oil per pole kg to be specified

Weight total per pole kg to be specifiedType of oil and reference specification to be specifiedPermissible secondary short circuit current A to be specified

Applicable standard(s) IEC 60044-2,60044-5





Table 14: 33kV Current Transformer



Model to be specifiedInstallation outdoorRated maximum voltage kV 36Rated service voltage kV 33Rated lightning impulse (BIL) (at altitude less than

1000 M) kV 170

Power frequency withstand voltage (at altitude less

than 1000 M) kV 70

Rated frequency Hz 50Rated primary current

116.0 for line feeder A 400 - 200 - 100117.0 for transformer feeder A 800 - 400 - 200

Rated secondary currents A 1 - 1 - 1Number of cones:

118.0 for measuring purposes 1119.0 for metering purposes 1120.0 for protection purposes 2

Rated burden for measuring core VA 30 Accuracy class 0.5 M 5Rated burden for metering core VA 30

Accuracy class 0.2Rated burden for protection cores VA 30

Accuracy class 5 P 20Short-time current ratings:

121.0 Thermal (Ith) kA 25122.0 Dynamic (Idyn) kA 60

The minimum guaranteed instrument security fac-tor, for metering current transformer

to be specified

Impulse wave to be specifiedMechanical load of primary terminal:

123.0 Dynamic load N to be specified124.0 Static load N to be specified

Minimum creepage distance mm/kV 31Size and section of terminal bolts to be specified

Weight per pole kg to be specifiedWeight of oil per pole kg to be specifiedType of oil and reference specification to be specifiedDimensions mm to be specifiedWith all accessories for installation to be specified














kJ/kV 8

Pressure relief class class ASuitability for fault current kA 40Power frequency 1 min. withstand voltage, wet kV 70Maximum RIV at 1000 kHz measured at 1.05 timethe system highest voltage

micro V 500

Impulse withstand voltage of arrester insulationexternal assembly

kV crest 170

Maximum short circuit rating kA 25Overall height of arrester mm to be specifiedCreepage distance mm/kV 31Weight of arrester kg to be specified



equivalent Accessories: 132 kV surge arrester dischargecounter

127.0 Type outdoor128.0 Counter indication digital129.0 Protection class IP 54130.0 Number per 3 arresters 1






Table 16: 11kV Voltage Transformer



Model to be specifiedInstallation outdoorExecutionRated maximum voltage kV 12Rated primary voltage kV 11 /√3 Rated secondary voltage (second winding) kV 0.1/√3 Rated secondary voltage (third winding) kV 0.1/√3 Rated frequency Hz 50Impulse withstand voltage 1.2/50 micro s wave (at

altitude less than 1000 M) kV peak 95


than 1000 M) kV rms 38

Power frequency withstand voltage secondarywinding

kV rms 2

Rated output (second winding/ third winding): VA 100/100 Accuracy class

131.0 For metering 0.2132.0 For measuring 0.5133.0 For protection 3P

Voltage factor at rated voltage:134.0 Continuous 1.2135.0 30 second 1.5

Thermal limit burden VA to be specifiedNormal temperature rise: 28

136.0 Winding °C 50137.0 Oil °C 45

Maximum temperature rise under short circuit con-ditions:

138.0 Winding °C to be specified139.0 Oil °C to be specified

Total height mm to be specifiedMinimum creepage distance: mm/kv 31Size and section of terminals bolts mm to be specifiedWeight of oil per pole kg to be specified

Weight total per pole kg to be specifiedType of oil and reference specification to be specifiedPermissible secondary short circuit current A to be specified

Applicable standard(s) IEC 60044-2,60044-5





Table 17: 11kV Current Transformer



Model to be specifiedInstallation outdoorRated maximum voltage kV 12Rated service voltage kV 11Rated lightning impulse (BIL) (at altitude less than

1000 M) kV 95


than 1000 M) kV 38

Rated frequency Hz 50Rated primary current

140.0 for line feeder A 400 - 200 - 100141.0 for transformer feeder A 400 - 200 - 100

Rated secondary currents A 1 - 1 - 1Number of cones:

142.0 for measuring purposes 1143.0 for metering purposes 1144.0 for protection purposes 2

Rated burden for measuring core VA 30 Accuracy class 0.5 M 5Rated burden for metering core VA 30

Accuracy class 0.2Rated burden for protection cores VA 30

Accuracy class 5 P 20Short-time current ratings:

145.0 Thermal (Ith) kA 25146.0 Dynamic (Idyn) kA 60

The minimum guaranteed instrument security fac-tor, for metering current transformer

to be specified

Impulse wave to be specifiedMechanical load of primary terminal:

147.0 Dynamic load N to be specified148.0 Static load N to be specified

Minimum clearance mm to be specifiedMinimum creepage distance mm/kV 31

Size and section of terminal bolts to be specifiedWeight per pole kg to be specifiedWeight of oil per pole kg to be specifiedType of oil and reference specification to be specifiedDimensions mm to be specifiedWith all accessories for installation to be specified














kJ/kV 8

Pressure relief class class ASuitability for fault current kA 25Power frequency 1 min. withstand voltage, wet kV 38Maximum RIV at 1000 kHz measured at 1.05 timethe system highest voltage

micro V 500

Impulse withstand voltage of arrester insulationexternal assembly

kV crest 95

Maximum short circuit rating kA 25Overall height of arrester mm to be specifiedCreepage distance mm/kV 31Weight of arrester kg to be specified



equivalent Accessories: 132 kV surge arrester dischargecounter

151.0 Type outdoor152.0 Counter indication digital153.0 Protection class IP 54154.0 Number per 3 arresters 1






Table 19: 132kV Dead-End and Suspension Insulators - Discs

Minimum Requirements Data offered by

BidderDescription Unit DataManufacturer's name to be indicatedMaterial porcelain, glass

discRated maximum voltage (String) kV 145Service voltage (String) kV 132Individual Disc Data

Disc diameter (minimum) mm 254Spacing mm 146Flashover values:Power frequency voltage kV rms 132Power frequency

6.0 Dry kV 957.0 Wet kV 55

Lightning impulse:8.0 Positive kV 1259.0 Negative kV 130

Radio interference voltage (RIV):10.0 Test voltage to ground kV 1011.0 Max. RIV at 1000 kHz micro V 50

Nominal creepage distance mm 432Dry arcing distance mm 203.2Weight: kg to be indicated

Accessories: to be indicated12.0 Clevis13.0 Tongue fittings

ANSI class 52.6 Applicable Standard(s) IEC 60016,

IEC 60305,IEC 60433,IEC 60076,IEC 60289





Table 20: 132kV Post-Type Insulators


Manufacturer's name to be indicated

Material porcelain orpolymer

Installation outdoorRated maximum voltage kV 145Rated service voltage kV 132Lightning impulse withstand voltage (at altitude less

than 1000 M) kV peak 650

Power frequency 1 min. withstand voltage (at

altitude less than 1000 M) kV 275

Maximum RIV at 1000 kHz micro V 500Nominal creepage distance mm/kV 31Mechanical values:

14.0 Cantilever kg 80015.0 Tensional strength kgm 400

Weight: kg to be specified Accessories: to be specified

16.0 Connectors17.0 Joints18.0 Clamps

Applicable Standard(s) IEC 60016,IEC 60168,IEC 60865,IEC 60273DIN 48 013





Table 21: 33/0.4kV Auxiliary Transformer


Manufacturer to be specifiedType 3-phase, oil-

immersedInstallation indoorMaximum Opering Voltage kV 36 / 0.430Rated service voltage:

19.0 Primary side (high voltage) kV 3320.0 Secondary side (low voltage) kV 0.4

Rated power kVA 100Rated frequency Hz 50Rated current:

21.0 Primary side (high voltage) A to be specified22.0 Secondary side (low voltage) A to be specified

Vector group Dyn11Impedance voltage % 4Type of cooling ONANOff-load tap changer regulation ± 2 x 2.5%Losses:

23.0 No-load losses W to be specified24.0 Load losses W to be specified

Rated power frequency withstand voltage kV 70Rated lightning impulse withstand voltage kV peak 170Sound power level dB (A) 68Painting Admiralty Grey

shade No. 632 asper BS 381C

Dimensions:25.0 Length mm to be specified26.0 Width mm to be specified27.0 Height mm to be specified28.0 Distance between the wheel's

centresmm to be specified

Total weight kg to be specifiedOil weight kg to be specified

Applicable standard(s) IEC 60076





Table 22: Low Voltage AC Distribution Panel for Auxiliary Services


General

Manufacturer's name to be specified

Type metal clad, in-door, air insu-

latedInstallation indoorRated Voltage V 400/230Rated frequency Hz 50BusbarRated currents A to be specifiedMaterial copperShort-circuit current (1 s.) kA 10Number of 3-phase outgoings to be specifiedNumber of 1-phase outgoings to be specifiedProtection IP 4X

Equipment29.0 Main 3-phase 4-poles moulded case

circuit breaker for incoming feeder

to be specified

30.0 3 current transformer to be specified

31.0 3-phase active energy meter to be specified

32.0 1 AC current meter to be specified

33.0 1 current switch, 3 positions to be specified

34.0 1 AC volt meter to be specified

35.0 1 rotary voltage switch, 7 positions to be specified

36.0 3-phase 4-pole moulded case circuitbreaker for outgoing feeders

to be specified

37.0 1-phase 2-pole moulded case circuitbreaker for outgoing feeders

to be specified

38.0 1 outlet socket 220 V, 50 Hz, 10 A to be specifiedDimensions

39.0 length mm to be specified

40.0 height mm to be specified

41.0 depth mm to be specifiedWeight kg to be specified

Applicable standard(s) IEC 60364IEC 60439VDE 0100





Table 24: Battery Charger


Manufacturer to be specifiedType 2 full capacity redun-

dantModel to be specifiedDesign fully electronic stan-

dard designCharacteristics I/U characteristic

with high tempera-ture stability

Circuit configuration 3-phase full wavebridge circuit

Installation indoor, in metal-cladcubicles with front

door; all equipmentaccessible from the

front sideProtection class IP41

AC supply:45.0 Rated service voltage V 400/23046.0 Frequency Hz 5047.0 Rated current A to be specified

DC output:48.0 Rated service voltage V 11049.0 Voltage setting range % ±550.0 Float charging voltage V 125 (at 2.23 V/cell)

51.0 Boost charging voltage V 2.4 per cell52.0 Regulation error of output voltage:- at load variation 0-100% % ± 1- at frequency variations 50 Hz % ± 5- at input voltage variation % ± 1053.0 Output voltage regulation with

current limiting range±2% within voltagerange of 80-100%

54.0 Regulation characteristic I/U as per DIN41773 or equivalent

55.0 Ripple content % < 10 (pp) withoutbattery

56.0 Permissible humidity acc. to IEC57.0 Radio interference "A" according to EN

5501158.0 Derating factor (thyristors) 2.3 as per VDE

016059.0 Cooling natural circulation60.0 Fuse switch disconnector (charger

output)to be specified

61.0 Control unit with integrated mainsfilter, phase failure supervision, soft startfacility, pulse blocking, cut-in delay

to be specified

Monitoring devices:62.0 Detailed fault alarm includingcollective fault alarm and additional visual

to be specified






signalling at front door63.0 Three-phase overvoltage and

undervoltage supervisionto be specified

64.0 Current-controlled DC undervoltage

supervision

to be specified

65.0 DC overvoltage supervision withdelayed/undelayed cut-off

to be specified

66.0 Integrated supervision of thyristorfuses

to be specified

67.0 Fuse supervision of auxiliary andcontrol circuits

to be specified

68.0 Ripple monitoring to be specified69.0 Time to recharge battery to 80%

capacity from fully discharged statehour 10

Measuring:70.0 Volt meter and ammeter (charger

output)to be specified

71.0 Battery tension, consumer tension to be specified72.0 Charger current, consumer current to be specified

Disturbance reports:73.0 Main failure, rectifier tensions too low to be specified74.0 Battery circle too low, rectifier

tension too high, battery deeply unloadedto be specified

75.0 Battery circle disturbed, ground faultplus/minus

to be specified

76.0 Capacity test negative, short circuit to be specifiedEfficiency % 80Weight kg to be specifiedWidth x depth x height mm to be specified

Applicable standard(s) IEC 60146IEC 60364IEC 60439IEC 60947





Table 25: Protection Relays

Minimum Requirements Data offered byBidderDescription- Protection and indication system Unit Data

LONGITUDINAL DIFFERENTIAL PROTECTIONAND BACK UP DISTANCE (87l/21)

Manufacturer to be specifiedType referenceRelay design (microprocessor based, numerical) Numerical

Auxialliary Voltage range (Vn= 110 V dc Vdc 77-150Input frequency range (50Hz Nominal) Hz 47.5-52.5Differential protection requirements Phase segregated protection Yes

Ratio and Vector correction for CTs Yes Adjustable biased differential protectioncharacteristics

yes

Sensitivity- For phase faults- For earth faults- Operating time

ms <30

Distance protection requirements

3 zone ph-ph & ph-E yesPhase fault & Earth fault characteristic shapes(Mho, Quad)

yes

Operating time ms <30SOTF YesPower swing Blocking ( depending on relayingpoint in the power system

yes

Voltage transformer supervison yestime delay for all zones yesZone enable/disable for all zones yesOther requirements

Thermal overload, 49 noCircuit breaker failure 50BF (dependent on

application)yes

Event recording function yes

Disturbance recording function yesFault locator function yes

Intergral operator interface for local interrogation yes

Programmable scheme logic yesUser friendly HMI, Window based software forrelay setting, relay configuration and event,disturbance and fault record management .

yes

carry continuous current 1A yesMake 6A max. for 0.2s yesBreak dc 50W resistive25W inductive (L/R 40ms)

yes

Self checking facility yes

Intergral intertrip send and receive, with externalinput interface

yes

CommunicationsProtection yes






Direct optical fibre 1300nm single modeControlCommunication ports ( Front/rear etc)(Note: Two Rear ports for NCC and RCC)

Physsical links (R485/Fibre optic)Protocol supported- IEC 60870-5-101- IEC 61850

yes

Type testsAtmospheric

Operation -25C and 55C for 96hrs, IEC 60068-2-1Transport/storage – 25 and 70C for 96 hrs, IEC

60068-2-

yes

Relative Humidity

Operation at 93%Tested to IEC 60068-2-3 with severity class 56days

yes

Enclosure

IEC 60529 IP50

yes

Mechanical Environment

Vibration IEC 60255-21-1Shock and bump IEC 60255-21-2Seismic IEC 60255-21-3

YesYesyes

Insulation

Rated Insulation1000V high impedance protection CT inputs250V for other circuits

1000V open contact withstand Dielectric testsIEC 60255-5-Series C of table 1Impulse voltageIEC 60255-5 test voltage 5kv

Yes

Yes

yes

Electromagnetic compatibility

1Mhz Burst disturbance test,IEC 60255-22-1 severity class IIElectrostatic dischargeIEC 60255-22-2 severity class IIIRadiated Electromagnetic field DisturbanceIEC 60255-22-3 severity class III

Test method A, 27Mhz through 500MhzElectromagnetic EmissionsIEC 60255-25Fast transient disturbanceIEC 60255-22-4 severity level IvType test certificates to be provided

Yes

Yes

Yes

Yes

Yes


DISTANCE PROTECTION (21)


Auxialliary Voltage range (Vn= 110 V dc Vdc 77-150Input frequency range (50Hz Nominal) Hz 47.5-52.5






Distance protection requirements

3 zone ph-ph & ph-E yesPhase fault & Earth fault characteristic shapes(Mho, Quad)

yes

Operating time ms <30SOTF YesPower swing Blocking ( depending on relayingpoint in the power system

yes

Voltage transformer supervison yesTime delay for all zones yesTeleprotection modes PUR/POR/Block yesDEF plain and Blocking modes yesZ1 min and max operating time (mid Zone)Zone enable/disable for all zones yesOther requirements

Thermal overload, 49 noCircuit breaker failure 50BF- (dependent onapplication)

yes


Disturbance recording function yesFault locator function yes



yes


yes



yes

Communications

ProtectionDirect optical fibre 1300nm single mode

yes

ControlCommunication ports ( Front/rear etc)

(Note: Two Rear ports for NCC and RCC)Physsical links (R485/Fibre optic)Protocol supported- IEC 60870-5-101- IEC 61850

yes



60068-2-

yes

Relative Humidity


yes






Enclosure

IEC 60529 IP50

yes


Vibration IEC 60255-21-1

Shock and bump IEC 60255-21-2Seismic IEC 60255-21-3

YesYesyes

Insulation

Rated Insulation1000V high impedance protection CT inputs250V for other circuits1000V open contact withstand Dielectric testsIEC 60255-5-Series C of table 1Impulse voltageIEC 60255-5 test voltage 5kv

Yes

Yes

yes


1Mhz Burst disturbance test,IEC 60255-22-1 severity class IIElectrostatic dischargeIEC 60255-22-2 severity class IIIRadiated Electromagnetic field DisturbanceIEC 60255-22-3 severity class IIITest method A, 27Mhz through 500MhzElectromagnetic EmissionsIEC 60255-25Fast transient disturbanceIEC 60255-22-4 severity level IvType test certificates to be provided

Yes

Yes

Yes

Yes

Yes


LOW IMPEDANCE BUSBAR PROTECTIONINCLUDING BREAK FAILURE PROTECTION


Auxialliary Voltage range (Vn= 110 V dc Vdc 77-150Input frequency range (50Hz Nominal) Hz 47.5-52.5State principle of operation i.e low impedance

Integral check zone feature (state principle of

operation)

Yes

Distributed bay modules and central Unit (Y/N) YesMaximum number of bays yes- Isolator replica ms <30CT saturation detector and stabilisation

Integral CT Supervision yesCT matching Functions yesPhase segregated protection ms <30Two stage breaker failure

Phase faults Earth fault

Facility to initiate the scheme by auxialiary contactsI,e Bucholz operation

Yes

Yes






2 out 4 check of current detectors Independentlysettable delay times for operation with and withoutcurrentInput trip contact

Yes

Yes

Other requirementsUser friendly HMI, Window based software forrelay setting, relay configuration and event,disturbance and fault record management .

yes


yes



yes

Communications


yes

ControlCommunication ports ( Front/rear etc)(Note: Two Rear ports for NCC and RCC)


yes



60068-2-

yes

Relative Humidity


yes

Enclosure

IEC 60529 IP50

yes


Vibration IEC 60255-21-1

Shock and bump IEC 60255-21-2Seismic IEC 60255-21-3

Yes

Yesyes

Insulation


Yes

Yes

yes


1Mhz Burst disturbance test,IEC 60255-22-1 severity class IIElectrostatic discharge

Yes

Yes






IEC 60255-22-2 severity class IIIRadiated Electromagnetic field DisturbanceIEC 60255-22-3 severity class IIITest method A, 27Mhz through 500Mhz

Electromagnetic EmissionsIEC 60255-25Fast transient disturbanceIEC 60255-22-4 severity level IvType test certificates to be provided

Yes

Yes

Yes


Multifunction Overcurrent & Earth faultprotection (50/51/50N/51N


Auxialliary Voltage range (Vn= 110 V dc Vdc 77-150Input frequency range (50Hz Nominal) Hz 47.5-52.5Number of phase CT inputsNumber of earth fault CT inputsStandard, Very and Extreme inverse and definitetime characteristics curves conforming toIEC60255

Yes

Number of inverse overcurrent functions per phaseNumber of high set overcurrent functions per phase Number of low set overcurrent functions per phaseNumber of inverse earth fault functionsNumber of high set earth fault functionsNumber of low set earth fault functionsNumber of group settingEarth fault element suitable of high impedanceREF (with external resistor)

Yes

operating time at 5X setting when configured forREF

ms 30

Suitable for Blocked overcurrent busbar protectionscheme

yes

Other requirements Thermal overload, 49 (Y/N)

Directional O/C and E/F (Y/N)Number of output relays

Rated for tripping Rated for control and alarm

Integral metering functions yesOpto-isolator inputs yesEvent recording function yes

Disturbance recording function yesIntergral operator interface for local interrogation yes

Programmable scheme logic yesUser friendly HMI, Window based software for

relay setting, relay configuration and event,disturbance and fault record management .

yes







yes

Self checking facility yesIntergral intertrip send and receive, with external

input interface

yes

CommunicationsProtectionDirect optical fibre 1300nm single mode

yes



yes

Type tests

Atmospheric


60068-2-

yes

Relative Humidity


yes

Enclosure

IEC 60529 IP50

yes



YesYesyes

Insulation

Rated Insulation1000V high impedance protection CT inputs250V for other circuits1000V open contact withstand Dielectric testsIEC 60255-5-Series C of table 1

Impulse voltageIEC 60255-5 test voltage 5kv

Yes

Yes

yes


1Mhz Burst disturbance test,IEC 60255-22-1 severity class IIElectrostatic dischargeIEC 60255-22-2 severity class IIIRadiated Electromagnetic field DisturbanceIEC 60255-22-3 severity class IIITest method A, 27Mhz through 500MhzElectromagnetic EmissionsIEC 60255-25Fast transient disturbanceIEC 60255-22-4 severity level Iv

Yes

Yes

Yes

Yes

Yes






Type test certificates to be providedMinimum Requirements Data offered by

BidderDescription- Protection and indication system Unit DataMultifunction Directional Overcurrent & Earth

fault protection (50/51/50N/51NManufacturer to be specifiedType referenceRelay design (microprocessor based, numerical) Numerical

Auxialliary Voltage range (Vn= 110 V dc Vdc 77-150Input frequency range (50Hz Nominal) Hz 47.5-52.5Number of phase CT inputsNumber of earth fault CT inputsThree phase VT inputMethod of determining zero sequence voltage

Broken delta VT input (Y/N)

Derived mathematically (Y/N)Standard, Very and Extreme inverse and definitetime characteristics curves conforming toIEC60255

Yes

Number of inverse DOC functions per phaseNumber of high set DOC functions per phase Number of low set DOC functions per phaseNumber of inverse DEF functionsNumber of high set DEF functionsNumber of low set DEF functionsNumber of group settingOther functions provided

Non directional O/C 50/51 (Y/N) Non directional E/F 50N/51N (Y/N) Thermal Overload 49 (Y/N) Suitable for Blocked overcurrent busbar

protection scheme Earth fault element suitable of high

impedance REF (with external resistor)Number of output relays

Rated for tripping Rated for control and alarm

Yes

Other requirements

Integral metering functions yesOpto-isolator inputs yesEvent recording function yes

Disturbance recording function yesIntergral operator interface for local interrogation yes


yes

carry continuous current 1A yesMake 6A max. for 0.2s yes

Break dc 50W resistive25W inductive (L/R 40ms)

yes








yes

Communications


yes



yes



60068-2-

yes

Relative Humidity


yes

Enclosure

IEC 60529 IP50

yes


Vibration IEC 60255-21-1Shock and bump IEC 60255-21-2

Seismic IEC 60255-21-3

YesYesyes

Insulation


Yes

Yes

yes


1Mhz Burst disturbance test,

IEC 60255-22-1 severity class IIElectrostatic dischargeIEC 60255-22-2 severity class IIIRadiated Electromagnetic field DisturbanceIEC 60255-22-3 severity class IIITest method A, 27Mhz through 500MhzElectromagnetic EmissionsIEC 60255-25Fast transient disturbanceIEC 60255-22-4 severity level IvType test certificates to be provided

Yes

Yes

Yes

Yes

Yes


TRANSFORMER DIFFERENTIAL PROTECTION







Auxialliary Voltage range (Vn= 110 V dc Vdc 77-150

Input frequency range (50Hz Nominal) Hz 47.5-52.5Differential protection requirements Phase segregated protection Yes

Ratio and Vector correction for CTs Yes Adjustable biased differential protectioncharacteristics

yes

Sensitivity- For phase faults- For earth faults- Operating time

ms <30

5 th Harmonic restraint yesOther requirements

High set element yesMagnetising current inrush restraint yesMeasurement and indication on MMI of phase HVand LV differential and bias current

yes

Separate function that performs overfluxingprotection with trip and alarm functions

Yes

Overcurent and earth fault yesEvent recording function yes

Disturbance recording function yesLatching output contact yes



yes


yes


Intergral intertrip send and receive, with external

input interface

yes

Communications


yes



yes


Operation -25C and 55C for 96hrs, IEC 60068-2-1

yes






Transport/storage – 25 and 70C for 96 hrs, IEC60068-2-

Relative Humidity

Operation at 93%

Tested to IEC 60068-2-3 with severity class 56days

yes

Enclosure

IEC 60529 IP50

yes



YesYesyes

Insulation


Yes

Yes

yes



Test method A, 27Mhz through 500MhzElectromagnetic EmissionsIEC 60255-25Fast transient disturbanceIEC 60255-22-4 severity level IvType test certificates to be provided

Yes

Yes

Yes

Yes

Yes


TRANSFORMER RESTRICTED EARTH FAULTPROTECTION

Manufacturer to be specified

Type referenceRelay design (microprocessor based, numerical) Numerical

Auxialliary Voltage range (Vn= 110 V dc Vdc 77-150Input frequency range (50Hz Nominal) Hz 47.5-52.5Differential protection requirements Phase segregated protection Yes

Principal of operation – high impedance yesRatio correction for CTs YesStabilising resistor and voltage dependent resistorincluded

yes

Sensitivity- For earth faults- Operating time at 5X

ms <25






reject harmonics produced by CT saturation yesOther requirements


Disturbance recording function yes

Latching output contact yesIntergral operator interface for local interrogation yes


yes


yes



yes

Communications


yes



yes



60068-2-

yes

Relative Humidity


yes

Enclosure

IEC 60529 IP50

yes

Mechanical EnvironmentVibration IEC 60255-21-1Shock and bump IEC 60255-21-2Seismic IEC 60255-21-3

YesYesyes

Insulation


Yes

Yes

yes


1Mhz Burst disturbance test, Yes






IEC 60255-22-1 severity class IIElectrostatic dischargeIEC 60255-22-2 severity class IIIRadiated Electromagnetic field Disturbance

IEC 60255-22-3 severity class IIITest method A, 27Mhz through 500MhzElectromagnetic EmissionsIEC 60255-25Fast transient disturbanceIEC 60255-22-4 severity level IvType test certificates to be provided

Yes

Yes

Yes

Yes


TRIP CIRCUIT SUPERVISION

Manufacturer to be specifiedType referenceRelay design(Electro-mech, static, numerical)

Auxialliary Voltage range (Vn= 110 V dc Vdc 77-150Operating time msSupervision of the whole trip circuit with CB openand closedRelay operated indicator

Type tests

Atmospheric


60068-2-

yes

Relative Humidity


yes

Enclosure

IEC 60529 IP50

yes



YesYesyes

Insulation


Yes

Yes

yes



Yes

Yes

Yes






Test method A, 27Mhz through 500MhzElectromagnetic EmissionsIEC 60255-25Fast transient disturbance

IEC 60255-22-4 severity level IvType test certificates to be provided

Yes

Yes


MULTI CONTACT TRIPPING RELAYS

Manufacturer to be specifiedType reference

Auxialliary Voltage range (Vn= 110 V dc Vdc 77-150Is relay mechanically latched or self resettingMethod used to reset latched relay (Hand orelectrical0

Minimum voltage at which reliable operation occurs Yes


yes

Relay operated indicator type yes



60068-2-

yes

Relative Humidity


yes

Enclosure

IEC 60529 IP50

yes



YesYesyes

Insulation


Yes

Yes

yes


1Mhz Burs disturbance test,IEC 60255-22-1 severity class IIElectrostatic dischargeIEC 60255-22-2 severity class IIIRadiated Electromagnetic field DisturbanceIEC 60255-22-3 severity class III

Yes

Yes

Yes






Test method A, 27Mhz through 500MhzElectromagnetic EmissionsIEC 60255-25Fast transient disturbance

IEC 60255-22-4 severity level IvType test certificates to be provided

Yes

Yes





Table 26: Telecommunication System


Applicable standards for insulation / EMC / ESDtests:

77.0 Protection IEC 60265-4, -5, -6 (22-1, -2, -3, -4) class III

IEC 6081-1, -2,-3, -4

IEC 60834-178.0 Telecontrol IEC 60255-4, -

5, -6, class II/IIIIEC 60801-1, -

2, -3, -4IEC 60870-1, -

2, -3, -4OLTE transceiver characteristics:

79.0 Optical wave length nm 1550 or 131080.0 Optical source laser81.0 Optical source life span better than 15

years82.0 Optical fibre type single mode83.0 Optical connectors Type FC-PC84.0 Jitter performance: ITU-T recom-

mendationG.823

85.0 Power supply V 48 V DC

86.0 Capacity Mbps 8Digital multiplexers:

87.0 spare channel capacity aftercommissioning on each transmission section(both main and backup)

≥ 30%

Optical fibre salient characteristics:88.0 Number of fibres 48 minimum89.0 Core diameter m 8.3 or 9 with a

± 3% tolerance90.0 Cladding design m either matched

or depressed

91.0 Clad diameter m 125.0 ± 292.0 Core-clad concentricity less than 2%93.0 Coating diameter m 250 ± 1594.0 Coating concentricity ≥ 0.795.0 Attenuation:- 1310 nm dB/km ≤ 0.40 - 1550 nm dB/km ≤ 0.22

96.0 Bending attenuation:- 1310 nm (75 mm) dB ≤ 0.05 (100

turns)- 1550 nm (75 mm) dB ≤ 0.10 (100

turns)97.0 Temperature dependence dB/km ≤ 0.05 (-20 to

+85°C)






98.0 Cut-off wave length nm ≤ = 1250Chromatic dispersion:

99.0 Zero dispersion at: nm 1310 ± 12100.0 Zero dispersion slope (max.) ps/nm²/km 0.092

101.0 Zero dispersion at nm 1550 ± 15102.0 Zero dispersion slope (max.) ps/nm²/km 0.085103.0 Mode field diameter:- 1300 nm mm 9.30 ± 0.50- 1550 nm mm 10.50 ± 1.00104.0 IL proof test level g/m² 35 x 10 6 105.0 Splice attenuation dB/splice 0.02106.0 Connector loss dB/connector ≤ 0.5

Construction requirements:107.0 Transmission parameters:- Bit error rate (path including terminals at

n x 2 Mbit/s

< 1 x 10 -10

- Jitter performance n x 2 Mbit/s acc. to G.823Teleprotection interface (test voltages according toIEC 60255-4):

108.0 Isolation (0.5 J, 1 min.) kV/DC 2109.0 Pulse 1.2/50 µs kV 1

Telephone system:110.0 Number of subscriber lines 1111.0 Number of trunk lines 1112.0 Equipped spare capacity after

commissioning% 30

113.0 Capacity for additional lines % 50 (min.)





Table 27: Control and Monitoring System


Panels:114.0 Pre-wired yes

115.0 Floor-mounted yes116.0 Steel sheet thickness mm ≥ 2 117.0 Protection class IP 52118.0 Maximum height m 2.25119.0 Door material glass

Bay units:120.0 Spare units for additional bays Pcs.

1 spare foreach type of

Bay unitprovided

yes

121.0 Power supply from station battery V DC 110Central Processing Units (PCU):

122.0 Microprocessor bus architecture bit 32123.0 Memory for system software type PROM124.0 Application software in battery-

buffered RAM or EPROM / Flash-PROMyes

125.0 Automatic time synchronization at allnodes of the network

yes

126.0 Fault indication LEDs on modulesand alarm messages on monitors

yes

127.0 Basic functions: logic, sequencecontrol, data processing, including codeconversion, text and alarm signal editing,and function units for binary processes

yes

128.0 Cycle times, selectable (for eachcontrol module)

ms 10, 20, 40, 50,100, 200, 250,

500, 1000, 2000129.0 Programming language: Elements

for logic, control loops, arithmeticyes

130.0 Minimum number of I/0 channels percomputer (analogue in / digital in / digitalout)

(see rel.chapter)

131.0 Spare % 25

Video display and control system:132.0 Power supply from station batteries V DC 110133.0 Number of monitors for each control

systemPcs. 3

134.0 Number of function keyboards:- liquid-proof keyboard Pcs. 1- exchangeable extended keyboard Pcs. 1135.0 Hardcopy printer Pcs. 1136.0 Event and record printer Pcs. 2137.0 Bus data channels Pcs. 1138.0 Event list events min. 400

139.0 Alarm list alarms min. 100140.0 Resolution:






- within computer ms 1- between computers ms 5141.0 External alarm outputs Pcs. 6142.0 Diagramme change speed sec. 5

143.0 Diagramme updating:- event-driven sec. 1- cyclic, adjustable sec. 3 to 10144.0 Transfer of manual command inputs sec. 1

Communication links:145.0 Data transmission rate Mbit/sec. 10146.0 Data transmission mode as serial

bus to IEEE 802.3 and CSMA / CD(Ethernet type)

yes

147.0 Conductor as duplex fibre optic cable yes148.0 Data transmission rate Mbit/sec. 10149.0 Number of buses per processing unit no. 2150.0 Nodes per buses Pcs. max. 45151.0 Transmission range (with fibre optic

cable)m 1000

Programming and services unit (personal computeror programming unit):

notebook orpersonal com-

puter152.0 Main processor type (or better) Pentium 166xx153.0 Main memory Mbyte min. 512154.0 Hard disc Gbyte min. 100155.0 Floppy disc drive 3.5" Mbyte 1.44156.0 Monitor type active LCD157.0 Interfaces serial and par-

allel158.0 Operating system OS, MS-DOS or

UNIX, Win-dows, latest

version159.0 Weight kg < 10160.0 Ambient temperature:- Operation °C 15 - 50- Storage °C 0 - 60- Transport °C -30 - +60

Electromagnetic interference tests:161.0 Insulation test, voltage test,

individual test:- Applicable standards IEC 60255-5,

IEC 60950- Test voltage AC kV/Hz 2/50- or DC (1 minute) kV 2.85- external circuits against internal circuits- external circuits against earth and against

earth other- internal circuits against earth

162.0 Impulse voltage test, type test:






- Applicable standards IEC 60255-5- Test level level III- Test voltage kV 5- External circuits against internal circuits µs pulse: 1.2/50

- External circuits against earthHF interference test, type test:

163.0 Applicable standard IEC 60255-22-1164.0 Test level III165.0 Test voltage (1 MHz attenuated,

repeat rate 400/sec.):- Common mode voltage kV 2.5- Differential voltage kV 1.0

Transient disturbance values / burst, type test166.0 Applicable standard IEC 60801-2167.0 Test voltage kV/ns 4, 5/50168.0 Burst duration ms 15169.0 Repetition time ms 300

Electromagnetic fields, type test170.0 Applicable standards IEC 60801-3

IEC 60255-22-3Electromagnetic discharges, type test

171.0 Applicable standard IEC 60801-2172.0 Test conditions front door

closed, closedpanel (covered)

173.0 Sharpness 3174.0 Test voltage kV 8

Electric meter175.0 Basic current l b A 3 x 5176.0 Load capacity in % of l b:- Metering 400- Thermal 500- Short circuit peak value of

50 l max and >25lmax during 1 µs

177.0 Rated voltage (U n) V 3 x 230 / 400178.0 Rated frequency Hz 50179.0 Accuracy class 0.2

180.0 No creep on voltage variation V 0.8 ÷ 1.15 U n 181.0 Starting load max. A 0.05% l b




27. SUPPLEMENTARY DRAWINGS



Volume II – Section VI: Employers Requirements: Contract 16 - 132/33 kV Substations and bays

Chapter 27: Bid Submission Supplementary Technical Requirements


TABLE OF CONTENTS

27 BID SUBMISSION SUPPLEMENTARY TECHNICALREQUIREMENTS .......................................................................................... 1

27.1 General .......................................................................................................... 1



Volume II – Section VI: Employers Requirements: Contract 16 - 132/33 kV Substations and bays

Chapter 27: Bid Submission Supplementary Technical Requirements

Energy Access Scale-up Program Page 1 Kenya Power and Lighting Company LimitedRevision No. R0 Substation Bidding Documents – October ’09

27 BID SUBMISSION SUPPLEMENTARY TECHNICAL REQUIREMENTS

27.1 GeneralThis Chapter provides specific Bid Submission requirements in respect of additional technical andrelated information that a Bidder is required to ensure the completeness of its Bid Submission inrespect to technical information, to supplement the provisions of Instructions to Bidders.Whenever there is discrepancy in respect to technical content of a Bid Submission, the provisionsherein shall prevail over those in the Instructions to Bidders.




28. DRAWINGS



FORMS AND PROCEDURES



Section VI: Forms and Procedures Contract: 16

Kenya Electricity Expansion Project

1Kenya Power and Lighting Company Limited Keep Bidding Documents – April 2011

Forms and Procedures

A NNEX 1. R EQUEST FOR CHANGE PROPOSAL ..................................................... ...................................................... 6 A NNEX 2. ESTIMATE FOR CHANGE PROPOSAL ..................................................................... .................................... 8 A NNEX 3. ACCEPTANCE OF ESTIMATE .................................................................................... ............................... 10 A NNEX 4. CHANGE PROPOSAL ............................................................................................................................... 11 A NNEX 5. CHANGE ORDER .................................................... ......................................................... ........................ 14 A NNEX 6. PENDING AGREEMENT CHANGE ORDER ................................................................................................. 15 A NNEX 7. APPLICATION FOR CHANGE PROPOSAL ..................................................................................... ............. 17






Form of Completion Certificate

Date:Loan/Credit N o:IFB N o:

______________________________

To: _________________________________

Dear Ladies and/or Gentlemen,

Pursuant to GC Clause 24 (Completion of the Facilities) of the General Conditions of the Contractentered into between yourselves and the Employer dated _____________ , relating to the

____________________, we hereby notify you that the following part(s) of the Facilities was (were)complete on the date specified below, and that, in accordance with the terms of the Contract, theEmployer hereby takes over the said part(s) of the Facilities, together with the responsibility for care andcustody and the risk of loss thereof on the date mentioned below.

1. Description of the Facilities or part thereof: ______________________________

2. Date of Completion: __________________

However, you are required to complete the outstanding items listed in the attachment hereto as soon as practicable.

This letter does not relieve you of your obligation to complete the execution of the Facilities inaccordance with the Contract nor of your obligations during the Defect Liability Period.

Very truly yours,

Title(Project Manager)






Form of Operational Acceptance Certificate


_________________________________________

To: ________________________________________

Dear Ladies and/or Gentlemen,

Pursuant to GC Sub-Clause 25.3 (Operational Acceptance) of the General Conditions of the Contractentered into between yourselves and the Employer dated _______________ , relating to the

___________________________________ , we hereby notify you that the Functional Guarantees of thefollowing part(s) of the Facilities were satisfactorily attained on the date specified below.

1. Description of the Facilities or part thereof: _______________________________

2. Date of Operational Acceptance: _______________________

This letter does not relieve you of your obligation to complete the execution of the Facilities inaccordance with the Contract nor of your obligations during the Defect Liability Period.

Very truly yours,

Title(Project Manager)






Change Order Procedure and Forms


CONTENTS

1. General2. Change Order Log3. References for Changes

ANNEXES

Annex 1 Request for Change ProposalAnnex 2 Estimate for Change ProposalAnnex 3 Acceptance of EstimateAnnex 4 Change ProposalAnnex 5 Change OrderAnnex 6 Pending Agreement Change OrderAnnex 7 Application for Change Proposal






Change Order Procedure

1. General

This section provides samples of procedures and forms for implementing changes in the Facilities duringthe performance of the Contract in accordance with GC Clause 39 (Change in the Facilities) of theGeneral Conditions.

2. Change Order Log

The Contractor shall keep an up-to-date Change Order Log to show the current status of Requests forChange and Changes authorized or pending, as Annex 8. Entries of the Changes in the Change OrderLog shall be made to ensure that the log is up-to-date. The Contractor shall attach a copy of the currentChange Order Log in the monthly progress report to be submitted to the Employer.

3. References for Changes

(1) Request for Change as referred to in GC Clause 39 shall be serially numbered CR-X-nnn.

(2) Estimate for Change Proposal as referred to in GC Clause 39 shall be serially numbered CN-X-nnn.

(3) Acceptance of Estimate as referred to in GC Clause 39 shall be serially numbered CA-X-nnn.

(4) Change Proposal as referred to in GC Clause 39 shall be serially numbered CP-X-nnn.

(5) Change Order as referred to in GC Clause 39 shall be serially numbered CO-X-nnn. Note: (a) Requests for Change issued from the Employer ’s Home Office and the Siterepresentatives of the Employer shall have the following respective references:

Home Office CR-H-nnnSite CR-S-nnn

(b) The above number “nnn” is the same for Request for Change, Estimate for Change Proposal,Acceptance of Estimate, Change Proposal and Change Order.






(e) You shall not proceed with the execution of the work for the requested Change until we haveaccepted and confirmed the amount and nature in writing.

(Employer ’s Name)

(Signature)

(Name of signatory)

(Title of signatory)






Annex 2. Estimate for Change Proposal

(Contractor’s Letterhead)

To: ______________________________ Date:

Attention: _______________________________

Contract Name: _______________________________ Contract Number: _____________________________

Dear Ladies and/or Gentlemen:

With reference to your Request for Change Proposal, we are pleased to notify you of the approximatecost of preparing the below-referenced Change Proposal in accordance with GC Sub-Clause 39.2.1 of theGeneral Conditions. We acknowledge that your agreement to the cost of preparing the Change Proposal,in accordance with GC Sub-Clause 39.2.2, is required before estimating the cost for change work.

1. Title of Change: ________________________

2. Change Request No./Rev.: ____________________________

3. Brief Description of Change: __________________________

4. Scheduled Impact of Change: ___________________________

5. Cost for Preparation of Change Proposal: _______________ 2

(a) Engineering (Amount)

(i) Engineer hrs x rate/hr =(ii) Draftsperson hrs x rate/hr =Sub-total hrs

Total Engineering Cost

(b) Other Cost

Total Cost (a) + (b)

(Contractor’s Name)

(Signature)

2 Costs shall be in the currencies of the Contract.






Annex 3. Acceptance of Estimate

(Employer ’s Letterhead)

To: ______________________________ Date:

Attention: ________________________________

Contract Name: _____________________________ Contract Number: ___________________________


We hereby accept your Estimate for Change Proposal and agree that you should proceed with the preparation of the Change Proposal.

1. Title of Change: ___________________________

2. Change Request No./Rev.: _______________________________

3. Estimate for Change Proposal No./Rev.: _______________________________

4. Acceptance of Estimate No./Rev.: _______________________________

5. Brief Description of Change: _______________________________

6. Other Terms and Conditions: In the event that we decide not to order the Change accepted,you shall be entitled to compensation for the cost of preparation of Change Proposal described in yourEstimate for Change Proposal mentioned in para. 3 above in accordance with GC Clause 39 of theGeneral Conditions.

(Employer ’s Name)

(Signature)

(Name and Title of signatory)






Annex 4. Change Pr oposal

(Contractor’s Letterhead)

To: _______________________________ Date:

Attention: _______________________________

Contract Name: _______________________________ Contract Number: _______________________________


In response to your Request for Change Proposal No. _______________________________ , we herebysubmit our proposal as follows:

1. Title of Change: _______________________________

2. Change Proposal No./Rev.: _______________________________

3. Originator of Change: Employer: [_______________________________ Contractor: _______________________________


5. Reasons for Change: _______________________________

6. Facilities and/or Item No. of Equipment related to the requested Change: _______________________________

7. Reference drawings and/or technical documents for the requested Change:

Drawing/Document No. Description

8. Estimate of increase/decrease to the Contract Price resulting from Change Proposal: 3

(Amount)

(a) Direct material(b) Major construction equipment

(c) Direct field labor (Total hrs)

(d) Subcontracts

(e) Indirect material and labor

(f) Site supervision

(g) Head office technical staff salaries

3 Costs shall be in the currencies of the Contract.






Process engineer hrs @ rate/hrProject engineer hrs @ rate/hrEquipment engineer hrs @ rate/hrProcurement hrs @ rate/hr

Draftsperson hrs @ rate/hrTotal hrs

(h) Extraordinary costs (computer, travel, etc.)

(i) Fee for general administration, % of Items

(j) Taxes and customs duties

Total lump sum cost of Change Proposal(Sum of items (a) to (j))

Cost to prepare Estimate for Change Proposal(Amount payable if Change is not accepted)

9. Additional time for Completion required due to Change Proposal

10. Effect on the Functional Guarantees

11. Effect on the other terms and conditions of the Contract

12. Validity of this Proposal: within [Number] days after receipt of this Proposal by theEmployer

13. Other terms and conditions of this Change Proposal:

(a) You are requested to notify us of your acceptance, comments or rejection of this detailedChange Proposal within ______________ days from your receipt of this Proposal.

(b) The amount of any increase and/or decrease shall be taken into account in the adjustment ofthe Contract Price.

(c) Contractor’s cost for preparation of this Cha nge Proposal: 2

(Contractor’s Name)

(Signature)

(Name of signatory)

2 Specify where necessary.






(Title of signatory)






Annex 5. Change Order


To: _______________________________ Date:

Attention: _______________________________

Contract Name: _______________________________ Contract Number: _______________________________


We approve the Change Order for the work specified in the Change Proposal (No. _______ ), and agree toadjust the Contract Price, Time for Completion and/or other conditions of the Contract in accordancewith GC Clause 39 of the General Conditions.

1. Title of Change: _______________________________

2. Change Request No./Rev.: _______________________________

3. Change Order No./Rev.: _______________________________

4. Originator of Change: Employer: _______________________________ Contractor: _______________________________

5. Authorized Price:

Ref. No.: _______________________________ Date: __________________________ Foreign currency portion __________ plus Local currency portion __________

6. Adjustment of Time for Completion

None Increase _________ days Decrease _________ days

7. Other effects, if any

Authorized by: Date:

(Employer)

Accepted by: Date:(Contractor)






Annex 6. Pending Agreement Change Order


To: _______________________________ Date:

Attention: _______________________________

Contract Name: _______________________________ Contract Number: [_______________________________


We instruct you to carry out the work in the Change Order detailed below in accordance with GC Clause39 of the General Conditions.

1. Title of Change: _______________________________

2. Employer ’s Request for Change Proposal No./Rev.: _______________________________ dated: __________

3. Contractor’s Change Proposal No./Rev.: _______________________________ dated: __________


5. Facilities and/or Item No. of equipment related to the requested Change: _______________________________

6. Reference Drawings and/or technical documents for the requested Change:

Drawing/Document No. Description

7. Adjustment of Time for Completion:

8. Other change in the Contract terms:

9. Other terms and conditions:

VolII KindarumamwingiGsafinal.pdf

Documents

Transcript of VolII KindarumamwingiGsafinal.pdf