(SOP) for Grid System Operation and Maintenance - Part2

11 KV INDOOR BUS BAR13. Bus Bar Supporting Insulators (broken/chipped, etc)

- Yes - Should be OK and no damage

14. Bus Bar Spout - Yes - - Should be OK as per design, intact, secured and no stresses.

15. Feeder Cable Spout - Yes - - Should be OK as per design, intact and no stresses.

16. Vermin Proofing Yes - - - Should be as per design, intact and secured

17. Cleaning of Bus Bar - Yes - - Should be OK. Clean and no dust, etc.

Tests on 11kV Bus Bar18. Insulation Resistance test (Megger test)

- - Yes - Should be as per commissioning test results and/or specifications after correction of test results at 20 °C

19. DC Hi Pot Test - - Yes - Should be as per commissioning test results and/or specifications

Contact Resistance Test for Electrical Joints

- - Yes - Good electrical joint has resistance ≤ 5µΩ

1

9. MAINTENANCE OF STATION GROUNDING SYSTEM

A typical Earth Mesh of Grounding System at Grid Station

Equipment Grounding Connection with Earth Mesh

Overhead Ground Conductor Shield/Sky Wire Connections

2

SOP CHECK SHEET: MAINTENANCE SCHEDULE AND CHECKS/TESTS OF STATION GROUNDING SYSTEMDescription of Inspection and Maintenance Work

Specified Time Period Remarks/Criteria/Standard/Safety PrecautionsD/W M3/6 Y1 Y5/10

1. Visual inspection (A walk around visual inspection from ground level and keeping in view the safe limits of approach to live and moving parts to check apparent condition, abnormal noise, rust on body of the equipment and component parts, etc.)

Yes - - - Wear PPE and carry basic tools, multi-meter, clip-on-ammeter, etc. Make entries of the observations in check sheets/note book.

2. Earth Mesh Layout - - - - Should be OK as per Approved Earth Mesh Layout Plan

3. Equipment Ground Connections (each equipment)

Yes - - - Should be OK and intact as per design

4. Fence Ground Connections

- Yes - - Should be OK and intact as per design/earth mesh layout plan

5. Station Building Ground Connections

- Yes - - Should be OK and intact as per design (separate mast)

6. Laying of Overhead Ground Conductor Shield/Sky Wire and Angle of Protection

Yes - - - Should be OK as per design. A 30° angle from top of the structure should be sufficient to protect the area.

7. Overhead Ground Conductor Shield/Sky Wire Connections with earth mesh, Condition, Fittings, Tension or Sag

- - Yes - Should be OK and intact as per design

8 Direct Earthing of Overhead Ground Conductor Shield/Sky Wire at Earth Mast


9. Earth Mesh Conductor Condition and Connections with Earth Electrodes

- - - Yes Should be OK and intact as per earth mesh design/earth mesh layout plan. Check by digging the earth as applicable

Tests10. Earth Resistance Test (at Each Equipment Ground Connections)

- Yes - - Should be OK as recommended (should be < 2 Ω)

11. Earth Mesh Integrity - - - Yes Should be OK and intact as per

3

Test (at Each Equipment Ground Connections) with 300 A Primary Injection Test Set and/or with Proper Test Set

design. Comparison of the test results with commissioning test results and/or previous test results can also be a reference.

Note. In heavy polluted areas, give special attention to equipment ground connections and grounding copper conductor. Follow special instructions in this regard if any.

4

10. MAINTENANCE OF 11KV CIRCUIT BREAKERS

11kV Circuit Breakers Panel Board at 220kV G/S NTDC NKLP Lahore

5

SOP CHECK SHEET: MAINTENANCE SCHEDULE AND CHECKS/TESTS OF 11 KV CIRCUIT BREAKERS

6

Description of Inspection and Maintenance Work




2. Abnormal Sound and Smell

Yes - - - There should be no abnormal noise, sound and smell

3. Panel Board Indication Lamps


4. Operation Counters Yes Should be OK and intact and operative

5. Panel Board Indicating meters


6. Panel Board Ground Connections (I/C and last O/G panels)

- Yes - - Should be OK and intact, tight and secured

7. Inter-Panels Ground Connections

- Yes - - Should be OK and intact, tight and secured

8. LV Compartment: Doors, Door locks, Door packing, Door stops, Light, Cleaning, Vermin proofing, Ground connections, etc.

Yes - - - Should be OK and no defect/damage

9. Space heaters & Thermostat setting if applicable

- Yes - - Should be OK and intact and operative

10. Wiring and Terminal Blocks

- Yes - - Should be OK and tight and secured

11. Protection Relays and Accessories


Note. LV Compartment are normally sealed so the inspection and maintenance frequency may changeCB Trolley & Compartment12. Trolley Rack IN/OUT way and Floor Level


13. Oil Replacement (for OCB)

- Yes and/or*

- - * Replace oil after 6-10 tripping whichever comes first. DES of oil > 30kV at 2.5 mm gap. Oil level should be OK as per indicator. The

7

indicator should be kept clean and visible. Should be no oil leakage

14. SF6 Gas Pressure (for GCB)

- Yes and/or*

- - * Check SF6 gas pressure after 6-10 tripping whichever comes first, should be OK as recommended and/or as per specifications. If needed makeup SF6gas pressure. Should be no gas leakage

15. Contact Wipe Check (for VCB)

- Yes and/or*

- ] * Check contact wipe after 6-10 tripping whichever comes first, as per the method prescribed in the equipment instruction book. Should be OK as per design

16. Doors, Door locks, Door packing, Door stops, Cleaning, etc.

- Yes - - Should be OK and no defect/damage

16. Auxiliary Plug Connector

- Yes - - Should be intact as per design

17. Panel Ground Connections


18. Trolley Rack In/Out Guide Ways


19. Arm Contacts (Bus Bar/Cable Side)


20. CB Mechanism (Inspection, Cleaning, lubrication, etc.)

- Yes and/or*

- - *Should be carried out after 6-10 tripping whichever comes first and should be OK and no defect/damage

21. Trolley Rack In/Out Locking (Service, Test, and Withdrawal Positions)


22.CB Major Maintenance / Overhauling

- - - Yes Should be carried out as recommended and/or as per specifications

Bus Bar & Cable Compartment23. Bus Bar & Cable Spouts - - Yes - Should be OK and intact as per

design24. Alignment of Trolley Contacts with Bus Bar & Cable Spouts. Means for physical verification of contact grip.

- Yes - Should be OK and intact as per design

25. Power Cable Termination

- - Yes - Should be OK and intact as per design. Should have no stresses

26. Power Cable Sheath/shield Grounding

- - Yes - Should be OK and intact and no damages

27. O/G Panel CT - - Yes - Should be OK and intact/ secured as

8

(Mounting, cleaning, connections, etc.)

per design

28. I/C Panel CT/PT (Mounting, cleaning, connections, etc.)

- - Yes - Should be OK and intact/secured as per design

Tests29. Insulation Resistance Test (Poles, Bus Bar, Power Cables)

- - Yes - Should be OK as per commissioning test results and/or as per specifications after correction of test results at 20 °C

30. DC Hi Pot Test (Poles, Bus Bar, Power Cables) (special test)

- - Yes - Should be OK as per commissioning test results and/or as per specifications

31. Contact Resistance Tests of CB


32. Vacuum Degree of VCB Interrupters (using VIDAR or DC Hi Pot set)


32. Contact Wipe Check of VCB Interrupters


33. Earth Resistance Test of Panel Board Ground connections

- Yes - - Should be OK as per commissioning test results and/or ˂ 2 Ω

11. MAINTENANCE OF DC BATTERIES/STATION BATTERY BANK

9

DC Battery Room at 220kV G/S NTDC Sammundri Road Faisalabad

220 VDC Battery Bank

SOP CHECK SHEET: MAINTENANCE SCHEDULE AND CHECKS/TESTS OF DC BATTERIES/STATION BATTERY BANK

10




Yes - - - Wear PPE and carry basic tools, multi-meter, clip-on-ammeter, etc. Make entries of the observations in check sheets/note book..

2. Battery Room Exhaust Fan

Yes - - - Should be OK and operative

3. Electrolyte Level in Cells Yes - - - Should be OK as per indicator4. Voltage of Pilot Cell (s) Yes - - - Should be OK as per specification.5. Specific Gravity of Pilot Cell (s)

Yes - - - Should be OK as per specifications after correction of S.G. at 25 °C

6. Voltage of each Cell - Yes - - Should be OK as per specification7. Specific Gravity of each Cell

- Yes - - Should be OK as per specification after correction of S.G. at 25 °C

8. Battery Stand Level and Condition

Yes - - - Should be OK as per design and no damage

9. Inter-cell Spacing and Connectors

- Yes - Should be OK as per design, adjust if required. Connector should be tightened at recommended torque.

10. Vent Plugs or Filters of Cells

- Yes - - Should be cleaned with water. Do not rub the ceramic venting plugs

11. Cell terminals Cleaning - Yes - - Should be cleaned, and apply no-oxide compound.

12. Manual Boost Charge - Yes - - Put the battery bank on manual boost charge for 24 hours

13. Battery Maintenance Tools and Accessories (Hydrometer, Thermometer, Volt meter, Insulated Spanner, Plastic jug, Plastic funnel, PPE, etc.

Yes - - - Must always be available in battery room

Tests14. Battery Impedance Test - - Yes - Should be OK as per commissioning

test results and/or specifications. Replace the suspected cell/s

15. Battery Ampere Hour (AH) Capacity Test

- - - Yes Arrangements should be initiated for replacement of the battery bank if test AH capacity is ˂ 80%

Correction of SG at 25°C temperature

11

S25 = St + 0.0007 (t-25) whereS25 = Corrected SG at 25 °C, St = SG at temperature t °C of electrolyte, 0.0007 = assumed temperature coefficient of SGCorrection of AH discharge capacity at 25°CC25 = Ct / 1 + 0.008 (t – 25) whereC25 = the discharge capacity corrected at 25 °C, Ct = AH capacity at temperature t °C of electrolyte, 0.008 = assumed temperature coefficient of discharge capacity.

Impedance correction at temperature 77 °F for the conventional flooded battery types or vented batteries

Zb = 0.008 (Zm) / (T+30)^-0.520 Ω where: Zb = Corrected battery impedance to 77 °F

Zm = Measured impedance valueT = Measured temperature of electrolyte in °F

Note. This formula is not applicable to Valve-Regulated or sealed cell batteries

12. MAINTENANCE OF DC BATTERY CHARGERS

12

220 VDC Battery Charger at 220kV G/S NTDC NKLP Lahore

SOP CHECK SHEET: MAINTENANCE SCHEDULE AND CHECKS/TESTS OF DC BATTERY CHARGERS

13





2. Abnormal Sounds and Smell

Yes - - - Should be OK and no abnormal sound/smell

3. Vermin proofing Yes - - - Should be OK and intact4. Cubicle: Doors, Door locks, Door packing, Door stops, Light, Cleaning, etc.


5. Front panel Indication lamps

Yes - - - Should be OK as per design

6. DC Grounding - Yes - Should be no grounding of + or – DC supply (give attention to grounding relay)

7. Control Switches and Accessories

Yes - - - Should be intact as per design

8. Automatic Float/Boost Function


9. Manual Float/Boost Function


10. Float/Boost Voltage Setting

- Yes - - Should be OK as per specifications

11. Ripple in output DC voltage

- - Yes - Should be OK as per specifications (ripples should be < ± 3%)

12. Indicating Meters Accuracy

- - Yes - Should be OK As per specifications

13. Under/Over Voltage Protection

- - Yes - Should be OK as per specifications

14. Current Limiter Setting - - Yes - Should be OK as per specifications15. Body Ground Connections

Yes - - - Should be OK and intact and tight

16. Audible Alarm Function Yes - - - Should be OK and intact and operative



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13. MAINTENANCE OF AUXILIARY SUPPLY SYSTEM

15

Three-phase, 250KVA, 11000V/400V Auxiliary Transformers at 220kv G/S NTDC NKLP Lahore

220VDC, 110DC and 400VAC Auxiliary Supply Panels at 220kv G/S NTDC NKLP Lahore

SOP CHECK SHEET: MAINTENANCE SCHEDULE AND CHECKS/TESTS

16

OF AUXILIARY SUPPLY SYSTEMDescription of Inspection and Maintenance Work




Auxiliary Transformers2. Abnormal Sounds and Smell


3. Vermin Proofing Yes - - - Should be OK and intact4. Cubicle: Doors, Door locks, Door packing, Door stops, Light, Cleaning, Proper Glands for Cable Entrance, Vermin Proofing, etc.


5. Cable Terminations Yes - - - Should be OK intact and secure6. MCB, Switches and Fuses


7. Transformer Body Ground Connections

- Yes - - Should be OK and intact and secured

8. Transformer Neutral Ground Connections

- Yes - - Should be OK and intact and secured

9. Off circuit tap changer - - Yes - Should be OK and operativeTransformer Tests10. Insulation Resistance Test

- - - Yes As per commissioning test results and/or specifications after correction of test results at 20 °C

11. Oil DES Test - - - Yes DES value should be >30kVAuxiliary Supply Panels (AC/DC)12. Abnormal Sounds and Smell


13. Vermin Proofing Yes - - - Should be OK and intact14. Doors, Door locks, Door packing, Door stops, Light, Cleaning, Proper Glands for Cable Entrance, Cable Numbering, Vermin Proofing, etc.


17

15. Cable Terminations Yes - - - Should be OK and intact and secured

16. MCB, Switches and Fuses


17. Ground Connections Yes - - - Should be OK and intact and secured



19. DC Grounding Relay Yes - - - Should be OK and intact and functioning. Test the relay after every 6 months. Alarm and indication function should be OK and intact

20. No/Loss of AC supply Relay

Yes - - - Should be OK and intact and functioning. Test the relay after every 6 months. Alarm and indication function should be OK and intact

21. Space heaters & thermostat setting if applicable


22. Cable Numbering - - Yes - Should be OK and intact and secured as per scheme

14. MAINTENANCE OF SHUNT REACTORS

18

500 kV 22MVAR Shunt Reactor at 500 kV Grid Station NTDC Sheikhupura

SOP CHECK SHEET: MAINTENANCE SCHEDULE AND CHECKS/TESTS SHUNT REACTORS

19


Specified Time Period Remarks/Criteria/Standard/Safety PrecautionsD/W M3-6 Y1 Y5-10



2. Oil level: Conservator Tank Main

Yes - - - Should be OK as per indicator. The indicator should be kept clean and visible. Should be no oil leakages

3. Oil level: Bushings Yes Should be OK as per indicator. The indicator should be kept clean and visible. Should be no oil leakages

4. De-railing locking devices Yes - - - Should be intact as per design5.Cooling System (AF): Fans Yes - - - Should be as per transformer

construction design and operative. Check for proper speed, correct direction and noisy bearings.

6. Cooling System(OF): Oil Circulation Pumps

Yes - - - Should be as per transformer construction design and operative. Check for correct direction and noisy bearings.

7. Oil Temperature Gauges Yes - - - Should be healthy and accurate 8. Oil Temperature Indicators

Yes - - - Should be OK at local/remote

9. Winding Temperature Gauges

Yes - - - Should be healthy and accurate

10. Winding Temperature Indicators

Yes - - - Should be OK at local/remote

11. Ground Connections of Neutral Terminal

Yes - - - Measure neutral current with clip-on-ammeter to ensure healthy connection between terminal and the earth mesh. Transformer neutral is grounded at two points i.e. with earth mesh and with separate earth electrode.

12. Ground Connections of Body Tank

Yes - - - Should be proper and tight. Measure leakage current with clip-on-ammeter to ensure healthy connection between the body tank and earth mesh. Transformer body tank has two grounding points.

20

13. Silica-gel Breather of Main Conservator Tank

Yes - - - Bubbling in the oil indicates healthy breathing. The colour of silica-gel should be BLUE and oil in glass pot clean. If 1/3 volume of the silica-gel has changed colour into PINK then recondition of replace the whole silica-gel

14. Oil Leakages all around the transformer

Yes - - - Should be no oil leakages

15. Bushing Condition (HV, Neutral, etc.)

Yes - - - Should be neat and clean, no damages and no oil leaks

16. Bushing Terminal Connections (HV, Neutral, etc.)

Yes* - Yes - Dismantle connections, clean properly, apply corrosion inhibitor and fix/tight with recommended torque. Should be no hotspot/s (* check during night patrolling/thermovision survey). While handling bushing terminal connections, take care of oil sealing system, arcing horns (if provided), the spacing between electrodes should be as per recommendations and/or in accordance with 1cm per kV of the rated phase-to-ground voltage. In 500/220 transformers, tertiary winding terminals are enclosed in separate cubicle, give special attention to water proofing and vermin proofing of the cubicle.

17. Radiator Tubes Fixture Yes - - - Should be secured with proper clamping/supports

18.Radiator Tubes Valves - - Yes - The valves should always be kept opened, operative and no oil leaks (the temperature of radiator tubes should be observed by touching the tubes and feeling the degree of hotness by comparison with each other tube

19. Pressure Relief Devices (PRD)/Auto Reset Relief Vent

- - Yes - Should be intact, no damages, and healthy micro switch and wiring terminal connections

20. Buchholz Relay - - Yes - Should be operative, no damages, arrow mark points toward conservator tank, 0.5o to 1o

ascending level towards conservator tank, gas sampling valve operative

21

(in some models a separate device for gas collection is provided near ground level of the transformer tank) , no oil leaks, cover packing healthy, neat & clean, proper glands at wiring cable entrance and moisture proofing, wiring terminals tight, velocity setting (65/100/150 cm per second, factory setting is normally at 100 cm/s), etc.

Control Cubicle21. Doors, Door locks, Door packing, Door stops, Light, Cleaning, Ground connections, Proper glands at wiring cable entrance, Wiring cable numbering, Vermin proofing, etc.


22. Space heaters & Thermostat setting

- Yes - - Should be intact and operative


- - Yes - Should be tight and secured

24. Control Switches and Accessories

- Yes - - Should be as per design, healthy and secured

Tests25. DES test of Oil of main tank and OLTC compartments

- - Yes - DES value should be >30kV, 40kV, 50kV at 2.5 mm gap for 66kV, 132kV, 220kV/ 500kV respectively

26. Chemical Analysis of Oil - - - Yes Should be as per test laboratory specifications

27. Tangent Delta (Tan δ) test of Oil

- - - Yes Should be as per test laboratory specifications

28. Dissolved Gases Analysis (DGA) of oil

- - Yes - Should be as per test laboratory specifications

29. Insulation Resistance test (Megger test) of Windings

- - Yes - Should be as per commissioning test results and/or specifications aftercorrection of test results at 20 °C

30. Insulation Resistance test (Megger test) of Core and/or Clamping


31. Capacitance and Dissipation Factor test (C&DF test) of windings and bushings

- - Yes - Should be as per commissioning test results and/or specifications aftercorrection of %DF test results at 20 °C

32. Winding Resistance test - - Yes - Should be as per commissioning test results and/or specifications after

22

correction of test results at 75 °C(*)33. Sweep Frequency Response Analysis (SFRA)

- - - Yes Should be as per commissioning test results and /or factory test results

34. Buchholz Relay functional tests; Alarm and Trip, Indications and Alarm

- - Yes - Should be OK and intact

35. Oil temperature; Alarm and Trip test, Indications and Alarm


36. Winding temperature; Alarm and Trip test, Indications and Alarm


37. Pressure Relief Device (PRD); Trip test, Indications (local, mechanical and remote) and Alarm


Note. CORRECTION OF INSULATION RESISTANCE TEST RESULTS AT STANDARD TEMP ERATURE 20 °CBecause most of the insulation materials have a negative temperature co-efficient i.e. , the resistance decreases with increase in temperature, so the IR value should be corrected to a standard temperature of 20 °C.

Roughly IR value decreases to ½ of its value for every 10 °C rise in the temperature above 20 °C. So for correction at 20 °C, for every 10 °C rise in the temperature above 20 °C, increase the measured value to 2 times. Formula for accurate temperature correction calculations;

IR 20 = IRt x 2^(t – 20) /10where IR 20 is the corrected value at 20°C, t is the temperature of insulation mass and IRt is

the measured insulation resistance value at temperature t °C.IR value is usually in mega ohms (M Ω).

Note. CORRECTION OF WINDING RESISTANCE TEST RESULTS AT STANDARD TEMPERATURE 75 °CThe measured of winding resistance value should be corrected to a standard temperature of 75 °C.

R 75 = Rt (235 + 75) / (235 + t) Ωwhere R 75 is the corrected value at 75°C, t is the winding temperature and Rt is the measured winding resistance value at temperature t °C.

15. MAINTENANCE OF GIS SUB STATTION

23

220kV GIS System at University Grid Station Islamabad

SOP CHECK SHEET: MAINTENANCE SCHEDULE AND CHECKS/TESTS OF GIS SUB STATIONDescription of Inspection and Maintenance Work

Specified Time Period Remarks/Criteria/Standard/Safety PrecautionsD/W M3-6 Y1 Y5/10

24

1. Visual inspection (A walk around visual inspection from ground level and keeping in view the safe limits of approach to live and moving parts to check apparent condition, abnormal noise, rust on body of the equipment and component parts, position of opening and closing indicators, etc.)


2. Test Operation of Ventilation Fans from Control at each Entrance Door of GIS Hall


3. Test Operation of Warning Bells


4. Availability of Respirators at each Entrance Door of GIS Hall

Yes - - - Respirators should always be available

5. Unusual Noise in Switchgear and Bus Bar Ducts

Yes - - - There should be no unusual/abnormal noise

6. SF6 Gas Pressure (GCB) Yes - - - Should be OK as per rated pressure/indicator and corrected at temperature 20 °C (*). The indicator should be kept clean and visible. Should be no gas leakages*(+0.025 bar for every 1°C above 20 °C)

7. Steel Structure Ground Connections


8. HV In/Out Terminal Connections

- - Yes - Dismantle connections, clean properly, apply corrosion inhibitor and fix/tight with recommended torque. Should be no hotspot/s (check during night patrolling/thermovision survey)

9. Supporting Structure Nut/Bolts/Level

- Yes - - Should be OK as per design, and tight and secured

10. Alignment Check of Disconnecting Switches/Isolators, as applicable

- Yes - - Should be OK as per provision in design and check method (in SE Switzerland make system at Ravi GIS substation Lahore, this alignment is checked by inserting a Teflon pin in the check holes)

25

11. Visual Check of CB Contacts Through Inspection Glass Hole, as applicable

Should be OK as per provision in design and check method (in SE Switzerland make system at Ravi GIS substation Lahore, provision has been made for visual check of the CB contacts through an inspection glass hole)

12. CTs; Secondary Terminal Box: Cover, Cover locks, Cover packing, Cleaning, Proper glands at wiring cable entrance, Wiring cable numbering, Vermin proofing, Ground connections, etc.

Yes - - - Should be OK and no damage/no defect, water proofing & vermin proofing intact

13. CTs; Secondary Terminal Connections


14. PTs; Secondary Terminal Box: Cover, Cover locks, Cover packing, Cleaning, Proper glands at wiring cable entrance, Wiring cable numbering, Vermin proofing, Ground connections, etc.


15. PTs; Secondary Terminal Connections


16. Earthing connections / Terminals

Yes - - - Should be tight and secured

Control Cubicles17. Cubicle Doors, Door locks, Door packing, Door stops, Light, Cleaning, Proper glands at wiring cable entrance, Wiring cable numbering, Vermin proofing, Ground connections, etc.


18. Control switches, Key switches, Indications, Accessories, etc.



Yes - - - Should be intact and operative

20. Wiring and Terminal Blocks - - Yes - Should be tight and secured21. Operation Counter Yes - - - Should be intact and operativeCBs; Motor Spring Operating Mechanisms22. Cubicle Doors, Door locks, Door packing, Door stops, Light,


26

Cleaning, Proper glands at wiring cable entrance, Wiring cable numbering, Vermin proofing, Ground connections, etc.23. Control switches, Key switches, Indications, Accessories, etc.




25. Wiring and Terminal Blocks - - Yes - Should be tight and secured26. Operation Counter Yes - - - Should be intact and operative27. Cleaning Yes - - - Should be OK neat and clean28. Closing Spring Motor Charging Time

- - Yes - Should be OK as recommended (usually < 15sec)

29. Lubrication of moving/sliding/rolling parts

- - Yes - Should be OK as per recommendations

30. Closing Dash Pot Oil Level - - Yes - Should be OK as per design31. Opening Dash Pot Oil Level - - Yes - Should be OK as per design32. Manual Charging of Closing Spring

- - Yes - Should be OK as per design

33. Supporting Structure Nut/Bolts/Level

- Yes - - Should be OK as per design, tight and secured

34. CB Close/Open or ON/OFF Indication (electrical/mechanical indicators)

Should be in accordance with the actual position of CB and OK as per design

CBs; Hydraulic Oil Pressure Operating Mechanisms35. Cubicle Doors, Door locks, Door packing, Door stops, Light, Cleaning, proper glands at wiring cable entrance, Wiring cable numbering, Vermin proofing, Ground connections, etc.






38. Wiring and Terminal Blocks - - Yes - Should be tight and secured39. Operation Counter Yes - - - Should be intact and operative40. Hydraulic Oil Level Yes - - - Should be OK as per design41. Hydraulic Oil Replacement - - - Yes Should be replaced as per

recommendations42. Hydraulic Oil Pressure Yes - - - Should be OK as per design43. Hydraulic Oil Leakages Yes - - - Should be no leakages44. N2 Gas Pressure - - Yes - Should be OK as per design

27

45. Hydraulic Oil: Low Pressure Alarm and Lockout Check

- - Yes - Should be OK as per design and remote indications

46. Hydraulic Oil Filter Check - - Yes - Should be OK as per design, clean or replace the filter as per recommendations

47. Hydraulic Oil Pressure Safety Valve Function Check


48. Hydraulic Oil Pump: Cut IN/OUT Pressure Value Check


49. Hydraulic Oil Pump and Accessories Mounting Structure Nut/Bolts/Level

Yes - - - Should be OK as per design, Tight and secure

CB; Pneumatic Operating Mechanisms50. Cubicle Doors, Door locks, Door packing, Door stops, Light, Cleaning, proper glands at wiring cable entrance, Wiring cable numbering, Vermin proofing, Ground connection, etc.




52. Space heaters & Thermostat Yes - - - Should be intact and operative53. Wiring and Terminal Blocks - Yes - - Should be tight and secured54. Operation Counter Yes - - - Should be intact and operative55. Rated Air Pressure Yes - - - Should be OK as per design56. Rated Air Pressure: Low Pressure Alarm and Lockout Check


57. Air Compressor: Air Intake Filter Check

- Yes - - Should be OK as per design, clean or replace filter as per recommendations

58. Air Compressor: Lubrication Oil Level and Condition Check

- Yes - - Should be OK as per design, replace oil as recommended

59. Air Compressor: Operation Hours Counter Check


60. Air Pressure: Safety Valve Function Check

- - Yes Should be OK as per recommendations

61. Air Compressor and Accessories Mounting Structure Nut/Bolts/Level


Tests62. Test Operation: ON/OFF Local/Remote/Auto

- - Yes - Should be intact and operative along with remote indications

63. CB Position Mechanical Indication (ON/OFF)

Yes - - - Should be correct as per actual position

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64. D/S or Isolator Position Mechanical Indication (ON/OFF)

Yes - - - Should be correct as per actual position

65. SF6 Gas Purity Test (GCB) - - Yes - Purity should be > 97 %66. SF6 Dew Point/Moisture Contents Test (GCB)

- - Yes - Dew point should be >-15°C or Moisture contents should be < 50 PPM

67. Contact Resistance Test - - Yes - Should be OK as recommended

68. Close/Open Time Test - - Yes - Should be OK as recommended. The permissible differences between timings of 3-poles and between timings of breaks within 1-pole are:Closing time: 5ms (1/4 cycle)Opening time: 3.33ms (1/6 cycle)Within breaks of 1-pole: 2.5ms (1/8 cycle)

69. Anti-Pumping Feature Check - - Yes - Should be OK and intact70. Pole Discrepancy Control Feature Check(applicable in single-pole operated CBs)

- - Yes - Should be OK and intact, remote indication

71. Minimum Voltage Close/Open Test

- - Yes - The CB should open at 50-75% voltage of rated value and close at 80% voltage of rated value

72. SF6 Gas: Low Pressure Alarm and Lockout Check


16. MAINTENANCE OF POWER CABLES AND CONTROL CABLES

29

11kV Power Cables Connected with Control Cables laid in Trench132/11 kV Power Transformer

132kV XLPE Power Cables Control Cables Coming from Cable room.Connected with 132kV GIS System at 220kV GIS University Islamabad

SOP CHECK SHEET: MAINTENANCE SCHEDULE AND CHECK/TESTS OF POWER CABLES AND CONTROL CABLES

30





2. Cable Marking / Numbering


3. Cable Terminations and Shield Ground

- Yes - - Should be OK and intact and secured as per design

4. Oil Pressure in Oil-Filled Cables

- - - - Should be OK as recommended

5. Patrolling along the Cable Route

- Yes - - Patrolling should be carried regularly, there should be no damage, no encroachment, etc along the cable route.

6. Control Cables Laying (runners, cable hangers, cable raceways, cable trays, in the trenches and cable room, etc.)

- Yes - - Should be OK as per design

Tests7. Capacitance and Dissipation Factor test (C&DF test)

- - Yes - Should be as per commissioning test results and/or specifications aftercorrection of %DF test results at 20 °C

8. Insulation Resistance test (Megger test)


Note.1. Each length of cable should be calculated according to requirements of design and route to reduce

the cable joints.2. Power cables and control cables should not be placed on the same line of the support.3. In the three phase four wire system, the cable with four cores should be applied. The cables with

three cores combined with another single cable or wire must be forbidden and the metal sheath of three core cables cannot be used as the neutral line.

4. The electric power cables which are servicing in a parallel formation, both cable type and length shall be same.

5. The distance among each supporting point and bend radius should comply with the requirement of

31

the design.6. High and low voltage power cable and control cable should be placed in sequence.

7. DC supply and AC supply control cable should be placed in sequence.

8. Installation of Cable in Pipe; The cable pipes should be clean before the cable is installed. There should be no ponding or sundries in the pipe. When the cable is installed, the protective cover layer should not be damaged. The non-corrosive lubricant/powder should be applied.

9. Installation of cable directly buried; There may be mechanical damage, chemical damage, underground current, vibration, heat, humid substances, and insect damage to underground cable, therefore the protective measure should be applied.

10. The soft soil and sand should be covered under and on the cable no less than 100mm and the protective cover should be placed. The covered width should be more than 50mm of the two sides of the cable. The protective cover could apply concrete plate or brick. There should be no stone or other substance in the soft soil and sand.

11. The marking signs should be installed at the turning corner, straight joints connection position of cable routine at regular intervals in cable route.

17. MAINTENANCE OF SHUNT CAPACITOR BANKS

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11kV Capacitor Bank at 220kV Grid Station NTDC NKLP Lahore

SOP CHECK SHEET: MAINTENANCE SCHEDULE AND CHECKS/TESTS SHUNT CAPACITOR BANKS (132KV & 11KV)

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Specified Time Period Remarks/Criteria/Standard/Safety PrecautionsD/W M3-6 Y1 Y5-10



2. Capacitor Tank Condition Yes - - - Tank body should be intact and have no signs of bulging or rupture. OK as per indicator. The capacitor unit should be kept clean

3. Capacitor Oil Leakage Yes - - - Should be no oil seepage or leakages4. Fuses Condition (for 11kV only)

Yes Should be OK as per design

5. De-railing locking devices Yes - - - Should be intact as per design6.Bus Bar or Line Connections

- - Yes - Dismantle connections, clean properly, apply corrosion inhibitor and fix/tight with recommended torque. Should be no hotspot/s (check during night patrolling/thermovision survey).

7.Ground Connections Yes - - - Should be OK as per design8. Supporting Structure Nut/Bolts/Level


9. Porcelain Insulators Condition

Yes - - - Should be clean and no damage

10.Neutral CT Condition Yes - - - Should be OK as per design, and tight and secured

11. Neutral CT Connections (P1&P2)

- - Yes - Dismantle connections, clean properly, apply corrosion inhibitor and fix/tight with recommended torque. Should be no hotspot/s (check during night patrolling/thermovision survey)

12. Oil Level in Neutral CT (132kV only)

Yes - - - Should be OK as per indicator. The indicator should be kept clean and visible. Should be no oil leakages

13. 132kV Neutral CT: Secondary Terminal Box: Cover, Cover locks, Cover packing, Cleaning, Proper glands at wiring cable


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entrance, Wiring cable numbering, Vermin proofing, Ground connections, etc.14. Neutral CT: Secondary Terminal Connections


15. Grounding/Discharging Switch Condition

- - Yes - Should be OK as per design, and operative and secured

Tests16. Capacitance Test of Bank or unit Capacitor (or C&DF Test as applicable).C&DF Test of Neutral CT

- - - Yes Should be as per name plate data or commissioning test results and/or specifications aftercorrection of %DF test results at 20 °C

17. Insulation Resistance test (Megger test) of Insulators

- - - Yes Should be as per commissioning test results and/or specifications aftercorrection of test results at 20 °C

18. Neutral CT: Magnetizing or Exciting Current/Knee-Point Voltage Test (special test)

- - - Yes Should be as per commissioning test results and /or specification

19.Neutral CT: Current Ratio and Accuracy Test (special test)

- - - Yes As per selected primary/secondary current ratio and /or specifications. Accuracy test results should be in accordance with the relevant Metering/ Protection core specifications.

Note.1) All capacitor units in the bank must be of the same Voltage rating and KVAR rating.2) Upon damage of one or more capacitor units in the bank, it must be ensured to avoid voltage

in excess of 110% on the remaining units in a group in each phase.3) Before working on capacitor units, these must be discharged completely.

18. MAINTENANCE OF FIRE DETECTION AND FIRE FIGHTING ARRANGEMENTS

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Fire Fighting arrangements at Grid Station

SOP CHECK SHEET: MAINTENANCE SCHEDULE AND CHECK/TESTS OF FIRE DETECTION AND FIRE FIGHTING ARRANGEMENTSDescription of Inspection and Maintenance Work


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2. Fire/Smoke detectors - Yes - - Should be OK as per design intact and operative

3. Water Sprinkling System (heat sensors, water supply and water storage tanks, piping, valves/regulators, etc.)

Yes - Yes - Should be OK as per design intact and operative

4. Oil Sump below the Transformers


5. Nitrogen Gas (N2) Injection System (Surgi-system) for Transformers

Yes - - - Should be OK as per design, intact and operative

6. Portable fire extinguishers chemical-foam type, CO2 gas type, etc.

Yes - - - Should be OK and as per design, intact and operative

7. Sand Buckets, Water Buckets, Shawls,

Yes - - - Should be OK and as per design, intact and useable

8. Partition Wall between Transformers

Yes - - - Should be OK and as per design, and intact

19. MAINTENANCE OF ARRANGEMENTS FOR WORK SUPPORT AND FACILITIES AT CONTROL BUILDING

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A view of Control Room at 220kV G/S NTDC NKLP Lahore

SOP CHECK SHEET: MAINTENANCE SCHEDULE OF ARRANGEMENTS FOR WORK SUPPORT AND FACILITIES AT CONTROL BUILDINGDescription of Inspection and Maintenance Work


1. Visual inspection of control and office buildings

Yes - - - Wear PPE and carry basic tools, multi-meter, clip-on-ammeter, etc.

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(A walk around visual inspection from ground level and keeping in view the safe limits of approach to live and moving parts to check apparent condition, abnormal noise, rust on body of the equipment and component parts, etc.)

Make entries of the observations in check sheets/note book.

2. Safety and security arrangements,

Yes - - - Should be OK intact and secured as per yardstick requirements

3. Work support provisions and facilities at Control room, Relay room, Battery room, Offices, Stores, Wash rooms, etc. (cleaning, drinking water supply, standby electricity supply arrangements, emergency lights, air conditioning, doors fittings, window fittings, fire detection, fire protection and fire fighting, personal protective equipment (PPE), distribution supply boards, first-aid-arrangements, emergency exits, safety awareness arrangements of the employees, etc.)

Yes - - - Should be intact and secure as per yardstick requirements

4. Lightning Arrangements (including emergency lights)

Yes - - - Should be OK as per design, intact and operative

20. MAINTENANCE OF ARRANGEMENTS FOR WORK SUPPORT AND FACILITIES AT OUTDOOR SWITCH YARD AREA

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Outdoor Switch Yard at 220kV Grid Station NTDC NKLP Lahore

SOP CHECK SHEET: MAINTENANCE SCHEDULE OF ARRANGEMENTS FOR WORK SUPPORT AND FACILITIES AT OUTDOOR SWITCH YARD AREADescription of Inspection Specified Time Period Remarks/Criteria/Standard/Safety

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and Maintenance Work PrecautionsD/W M3/6 Y1 Y5/101. Visual inspection (A walk around visual inspection from ground level and keeping in view the safe limits of approach to live and moving parts to check apparent condition, abnormal noise, rust on body of the equipment and component parts, etc.)


2. Lightning Arrangements Yes - - - Should be OK as per design, intact and operative

3. Safety and security arrangements,

Yes - - - Should be OK and intact and secured as per yardstick requirements

4. Transformer ways Yes - - - Should be OK and intact and operative

5. Roads/walking ways Yes - - - Should be OK and intact and operative

6. Sanitation , rain water drainage and disposal arrangements

Yes - - - Should be OK and intact and operative

7. Overall cleaning and pollution free atmosphere (maintenance of lawns, dealing with wild growth, etc.)

Yes - - - Should be OK and cleaned, intact and secured

8. Elimination or control of hazardous conditions for safety of the employees and the equipment.

Yes - - - Adequate safety arrangements should be made

9. Cable Trenches and Covers

Yes - - - Should be OK and cleaned, intact and secured

21. MAINTENANCE OF ARRANGEMENTS FOR LIVING SUPPORT AND FACILITIES AT RESIDENTIAL COLONY OF THE GRID STATION

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Mosque at Residential Colony of 220kV Grid Station NTDC NKLP Lahore

SOP CHECK SHEET: MAINTENANCE SCHEDULE OF ARRANGEMENTS FOR LIVING SUPPORT AND FACILITIES AT RESIDENTIAL COLONY OF THE GRID STATIONDescription of Inspection and Maintenance Work


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2. Safety and security arrangements

Yes - - - Should be OK intact and secured as per yardstick requirements

3. Drinking Water Supply Yes - - - Should be OK, clean/safe and secured as design

4. Roads/Streets/walking ways/Parks


5. Sanitation , rain water drainage and disposal arrangements


6. Overall cleaning and pollution free atmosphere (maintenance of lawns, dealing with wild growth, etc.)

Yes - - - Should be OK and cleaned

7. Elimination or control of hazardous conditions for safety of the residents.

Yes - - - Adequate safety arrangements should be made

6. MAINTENANCE SCHEDULE AND CHECKS OF PROTECTION RELAYS AND INSTRUMENTAION (P&I)

Preventive maintenance is a cycle of planned inspections, work activities and tests to be implemented to get and ensure for safe and reliable performance of different

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equipment and infrastructure components of the grid system. The maintenance cycle or frequency of implementation is given in terms of time-periods which can be modified due to weather conditions and constraints of the man-hours and quantity of the equipment in the jurisdiction of the work crew.

Periodic maintenance tests of protection relays/instruments and other devices are required to identify failure and degradation in service, so that corrective action can be taken. Because a protection scheme only operates under fault conditions, defects may not be revealed for a significant period of time, until a fault occurs. Regular testing assists in detecting faults that would otherwise remain undetected until a fault occurs.

The check sheets given hereunder describe only the maintenance schedules and checks/tests in terms of what to do and when to do. For the aspect of how to do, one should consult relevant manufacturer’s instructions, TSG training course books and/or TSG technical experts. In addition to the inspection and maintenance activities given in this SOP, manufacturer’s recommended instructions are also applicable.

The symbols used for time-periods for inspection and maintenance/frequency of implementation are as under:

D stands for daily, W stands for weekly, M stands for monthly,Y stands for yearly.

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A view of Relay Room at 220 kV NTDC G/S NKLP Lahore

An old Model Distance Protection Relay L8b & LZ 32 at 220 kV NTDC G/S NKLP Lahore

6.1 MAINTENANCE OF CONTROL PANELS (CP)

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SOP CHECK SHEET: MAINTENANCE SCHEDULE AND CHECKS/TESTS

46

OF CONTROL PANELS (CP)Description of Inspection and Maintenance Work




2. Abnormal Sounds and Smell


Vermin Proofing Yes - - - Should be OK and intact3. Indications bulbs/lamps Yes - - - Should be OK and healthy as per

design4. Semaphore Indicators Yes - - - Should be OK and healthy as per

design5. Indication Test/Reset Buttons


6. Indicating Meters AC & DC

Yes - - Should be OK and healthy as per design

7. Audible Alarm (Hooter) Yes - - -- Should be OK and intact and operative8. Control Markings Yes - - - Should be OK as per design9. Doors, Door locks, Door packing, Door stops, Light, Cleaning, Proper Glands for Cable Entrance, etc.


10. Cable Terminations Yes - - - Should be OK and intact and secure11. Cable Numbering - - Yes - Should be OK and intact and secured

as per scheme12. MCB, Switches and Fuses




14. Ground Connections Yes - - - Should be OK and tight and secured15. Space heaters & thermostat setting if applicable


6.2 MAINTENANCE OF PROTECTION RELAY PANELS (RP)

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Front view of Protective Relay Panels

Back side view of Protective Relay Panels

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SOP CHECK SHEET: MAINTENANCE SCHEDULE AND CHECKS/TESTS OF PROTECTION RELAY PANELS (RP)Description of Inspection and Maintenance Work




2.Abnormal Sounds and Smell


3. Vermin Proofing Yes - - - Should be OK and intact4. Relay Fittings Yes - - - Should be OK and intact and

secured5. Relay Indication Lamps, Flags, etc.

Yes - - - Should be OK and intact and secured

6. Control Number Markings


7. Doors, Door locks, Door packing, Door stops, Light, Cleaning, Proper Glands for Cable Entrance, etc.


8. Cable Terminations Yes - - - Should be OK and intact and secured

9. Cable Numbering - - Yes - Should be OK and intact and secured as per scheme

10. MCB, Switches and Fuses




12. Ground Connections Yes - - - Should be OK and tight and secured13. Space heaters & thermostat setting if applicable


6.3 MAINTENANCE OF TRANSMISSION LINE PROTECTION RELAYS AND INSTRUMENTATION (P&I)

49

SOP CHECK SHEET: MAINTENANCE SCHEDULE AND CHECKS/TESTS OF TRANSMISSION LINE PROTECTION RELAYS AND INSTRUMENTATION (P&I)Note. The Electromechanical relays have to be checked and tested annually as recommended below, whereas for the Numerical relays the test schedule should be on 5-10 yearly basesDescription of Inspection and Maintenance Work




2. Distance/Impedance Protection Relays

- - Yes - Should be OK as per specifications and protection scheme

3. Over Current Protection Relays


4. Earth Fault Protection Relays


5. Under Frequency Protection Relays


6. Under Voltage Protection Relays


6.4 MAINTENANCE OF TRANSFORMER PROTECTION RELAYS AND INSTRUMENTATION (P&I)

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SOP CHECK SHEET: MAINTENANCE SCHEDULE AND CHECKS/TESTS OF POWER/AUTO TRANSFORMERS PROTECTION RELAYS AND INSTRUMENTATION (P&I)Note. The Electromechanical relays have to be checked and tested annually as recommended below, whereas for the Numerical relays the test schedule should be on 5-10 yearly basesDescription of Inspection and Maintenance Work




2. Differential Protection relays


3. Over Current Protection Relays


4. Earth Fault Protection relays


5. Restricted Earth Fault Protection relays


6. Over Excitation Protection relays


7. Buchholz Protection relays


8. OLTC Protection relays - - Yes - Should be OK as per specifications and protection scheme

9. Oil Temperature Protection relays


10. Winding Temperature Protection relays


11. Rough Balance Protection relay


12. HV Connection Protection relay


13. LV Connection Protection relay


14.Over Voltage Protection relay


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6.5 MAINTENANCE MISCELLANEOUS PROTECTION RELAYS AND INSTRUMENTATION (P&I)

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SOP CHECK SHEET: MAINTENANCE SCHEDULE AND CHECKS/TESTS OF MISCELLANEOUS PROTECTION AND INSTRUMENTATION (P&I) EQUIPMENTDescription of Inspection and Maintenance Work




Miscellaneous ProtectionsNote. The Electromechanical relays have to be checked and tested annually as recommended below, whereas for the Numerical relays the test schedule should be on 5-10 yearly bases1. Bus Bar Protection relays - - Yes - Should be OK as per specifications

and protection scheme2. Breaker Failure Protection relays


3. DC Supervision relays - - Yes - Should be OK as per specifications and protection scheme

4. Trip Coil and Trip Circuit Supervision relays


5. Verification of Cross Trip Schemes


6. Verification of Inter-tripping Schemes


7. Annunciation Devices - - Yes - Should be OK as per specifications and protection scheme

8. Metering Devices - - Yes - Should be OK as per specifications and protection scheme

9. Auto Re-closing Schemes - - Yes - Should be OK as per specifications and protection scheme

Shunt Capacitor Bank ProtectionNote. The Electromechanical relays have to be checked and tested annually as recommended below, whereas for the Numerical relays the test schedule should be on 5-10 yearly bases1. Unbalance Protection relays


2. Over Current Protection relays


3. Synchronous Switching relay (if provided)


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11kV Feeder ProtectionNote. The Electromechanical relays have to be checked and tested annually as recommended below, whereas for the Numerical relays the test schedule should be on 5-10 yearly bases1.Over Current Protection - - Yes - Should be OK as per specifications

and protection scheme2. Earth Fault Protection - - Yes - Should be OK as per specifications

and protection scheme Energy meters 1. Accuracy check and calibration of Energy meters at internal metering points in the same company

- - Yes - Should be OK as recommended

2. Accuracy check and calibration of Energy meters at Cut off points/Common delivery points

- - Yes - Should be OK as per recommendations of WPPO Department

3. Accuracy check and calibration of Energy meters at IPPs connected with NTDC/DISCOsNote. These energy meters are to accuracy checked at the time of Annual Dependable Capacity (ADC) test

- - Yes - Should be OK as per recommendations of WPPO Department

7. MAINTENANCE SCHEDULE AND CHECKS OF TRANSMISSION LINES

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Preventive maintenance is a cycle of planned inspections, work activities and tests to be implemented to get and ensure for safe and reliable performance of different equipment and infrastructure components of the grid system. The maintenance cycle or frequency of implementation is given in terms of time-periods which can be modified due to weather conditions and constraints of the man-hours and quantity of the equipment in the jurisdiction of the work crew.

The check sheets given hereunder describe only the maintenance schedules and checks/tests in terms of what to do and when to do. For the aspect of how to do, one should consult relevant TSG training course books and/or TSG technical experts. In addition to the inspection and maintenance activities given in this SOP, manufacturer’s recommended instructions are also applicable.

The symbols used for time-periods for inspection and maintenance/frequency of implementation are as under:

D stands for daily, W stands for weekly, M stands for monthly,Y stands for yearly.

7.1 MAINTENANCE OF TRANSMISSION LINES

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220kV Double Circuit, Twin-bundle Transmission Line

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(SOP) for Grid System Operation and Maintenance - Part2

Documents

Transcript of (SOP) for Grid System Operation and Maintenance - Part2