AVK Catalogue Type DIG
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Self-regulating brushless synchronous alternators series DIG
Transcript of AVK Catalogue Type DIG
Self-regulating brushless synchronous alternatorsseries DIG
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Contents:
Applications
Ratings
Definition of the alternator3.1 Basic technical data3.2 Enclosure3.3 Cooling method3.4 Design
Mechanical features4.1 Construction4.2 Stator4.3 Rotor4.4 Bearing plates4.5 Bearings4.6 Terminal boxes
Derating factors5.1 Standard conditions5.2 Relation between
power and coolant temperature5.3 Relation between
power and installation altitude5.4 Relation between
power and cos phi: 5.5 Marine classification5.6 Higher types of enclosure
5.6.1 Enclosure IP 43 5.6.2 Enclosure IPR 44 or IPR 54 5.6.3 Enclosure IP 44 or IP 54
Electrical functions6.1 Operating principle
6.1.1 Alternator6.1.2 “COSIMAT N+” voltage regulator
6.2 Self-excitation, de-excitation6.2.1 Self-excitation6.2.2 De-excitation
6.3 Voltage and frequency6.3.1 Voltage adjustment range6.3.2 Steady-state voltage performance6.3.3 Transient voltage behaviour6.3.4 Voltage waveform
6.4 Currents6.4.1 Asymmetrical loads 6.4.2 Overload6.4.3 Short-circuit behaviour
6.5 Harmonic load6.6 Emergency operation
6.6.1 Emergency manual operation6.6.2 Stand-by control
6.7 Star point connection, neutral current
Parallel operation7.1 General7.2 Conditions for parallel operation 7.3 Start-up synchronisation for
isolated parallel operation7.4 Stationary operation / load distribution
7.4.1 Voltage droop7.4.2 Power factor regulation
7.5 Parallel mains operation7.6.Oscillations
Features of the medium voltage winding8.1 General8.2 Design and manufacture
Factory tests9.1 Standard tests9.2 Special tests (at extra charge)
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AVK SEG Competence in power generation and system protection
AVK SEG is a competent, reliablepartner in power generation andprotection technology. We offer the quality and flexibilityof a medium-sized, independentgroup of companies, which perfectly combine the experiencegained through many years with apolicy of innovative development.Active on a global basis, we supply not only a comprehensiverange of products, but also customer-specific engineering. Our product programme extendsfrom individual protection devicesthrough to complete electricalequipment for power plants. AvK Deutschland, the German company with its plant in Ingolstadtand a branch in Dreieich nearFrankfurt, supplies synchronous machines and converters, whilstSEG Kempen specialises in pro-tection and functional equipment.Together we set new standardsand exert an active influence on international power-generationtechnology. No matter what scopeof services you are looking for, we can deliver it – an individualdevice, an alternator or a com-plete turnkey system. Our extremely efficient customer service and ad-visory sales offices located acrossthe globe will make every effort to comply with your requirements.We not only build from a base of technological continuity and quality, but also place particularemphasis on customer satisfaction.The certification of the AvK andSEG plants in accordance withGerman industrial standard DIN EN ISO 9001 underlines the importance we attach to quality.
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AvK synchronous alternators from Series DIG 110 – 191are used in the following areas ofapplication:
● Continuous supply to stationary and maritimeplants
● Parallel peak-load operation
● Emergency supply to important consumers suchas power stations, industrial plants, hospitalsand tower blocks
● Combined heat and power stations (CHP)
● Electrical supply systemson board ship
● Diesel-electric drives forships
● Special-purpose suppliesto consumers with highmains-supply quality requirements
● No-break power systems(UPS)
● Frequency conversions,e.g. 50:60 Hz
They can be used with alltypes of drive system: dieselengines, gas engines, gas,hydraulic or steam turbinesand as shaft generators onboard ship.
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Applications
1.
Series DIG Self-regulating brushless synchronous alternators
Power station
Combined heat and power station
Diesel-driven generators on board ship
Shaft generator on board ship
Hydro-electric power station
Typical applications
Deutscher
Akkreditierungs
Rat
TGA-ZQ-004/92-00
C E R T I F I CAT E
DET NORSKE VERITAS ZERTIFIZIERUNG UND UMWELTGUTACHTER GMBH
certifies that the company
AvK Deutschland GmbH & Co. KG
in
D – 85051 Ingolstadt
has established a
quality system
in conformity with
DIN EN ISO 9001, 8.94
This Certificate is valid for:
Design, manufacturing and commissioning of
synchronous generators up to 30MVA,
asynchron motors and frequency converters
This Certificate is valid until:
2001-01-31
Certificate-Registration-No.:
ESN06940AQ98
Essen, 1998-01-09
Essen, 1998-01-09
M. Fröhlich
K. Nordhause
Manager
Lead-Auditor
This Certificate is only valid in connection with the original Certificate ESN06940AQ98.
Stand 01/98 D / &74924
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Ratings in accordance with VDE 0530, enclosure IP 23, criteria as in Item 3.1
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DIG 110 4 1500 1800 750 – 1080 900 – 1300 750 – 1080 750 – 1080 –6 1000 1200 580 – 750 720 – 940 560 – 720 – –
DIG 120 4 1500 1800 1300 – 2050 1630 – 2600 1300 – 1750 1150 – 1650 –6 1000 1200 900 – 1520 1130 – 1900 880 – 1200 1300 –8 750 900 750 – 1130 940 – 1410 – – –
10 600 720 600 – 960 750 – 1200 – – –
DIG 130 4 1500 1800 2250 – 3850 2850 – 4000 1900 – 3000 1800 – 2800 2050 – 32506 1000 1200 1730 – 2650 2000 – 3300 1450 – 2250 1350 – 2100 1600 – 25508 750 900 1180 – 1950 1470 – 2450 1140 – 1650 1300 – 1600 1700 – 1900
10 600 720 990 – 1550 1240 – 1700 800 – 1300 1060 – 1200 140012 500 600 790 – 1180 990 – 1470 650 – 1000 1080 –
DIG 140 4 1500 1800 4000 – 5600 4850 – 7000 3000 – 4600 3000 – 4400 3400 – 50006 1000 1200 3050 – 4050 3800 – 5050 2400 – 3500 2200 – 3250 2700 – 40008 750 900 2100 – 3080 2600 – 3850 1800 – 2650 1800 – 2600 2050 – 3050
10 600 720 1850 – 2200 2000 – 2750 1400 – 2100 1250 – 2100 1550 – 215012 500 600 1410 – 1880 1760 – 2300 1150 – 1500 1150 – 1550 1480 – 1650
DIG 150 4 1500 1800 5800 – 7400 7200 – 8100 5100 – 6850 4800 – 6050 5400 – 60006 1000 1200 4600 – 5200 5750 – 6500 3550 – 5500 3450 – 4950 4150 – 61008 750 900 3300 – 4500 4200 – 5000 2800 – 4800 2850 – 4500 3300 – 4600
10 600 720 2500 – 2800 3200 – 3550 2200 – 3300 2150 – 3000 2500 – 360012 500 600 2000 – 2650 2500 – 3300 1700 – 2600 1750 – 2500 1900 – 2750
DIG 156 4 1500 1800 7700 – 9600 9700 –11100 7300 – 9600 6600 – 8800 6700 – 88006 1000 1200 5600 – 7850 7050 – 9900 5600 – 7800 5300 – 7500 6600 – 88008 750 900 4700 – 6400 5400 – 8050 4700 – 6800 4400 – 6700 5200 – 7000
10 600 720 3000 – 4100 3700 – 5100 3400 – 5300 3200 – 5450 4100 – 550012 500 600 3250 – 4750 3400 – 6000 2800 – 4650 2500 – 4300 2950 – 4600
DIG 163 4 1500 1800 10100 –12600 – 9650 –14300 10500 –14100 –6 1000 1200 8200 –10500 10200 –13300 7800 –10500 7750 –10300 9500 –120008 750 900 7000 – 7500 7950 – 8400 7050 – 8550 6850 – 8400 7950 – 9200
10 600 720 5400 – 6700 6800 – 8200 5650 – 7400 5650 – 7100 6200 – 830012 500 600 5300 – 6150 6400 – 7300 4750 – 6050 4350 – 5850 5000 – 6200
DIG 171 6 1000 1200 10400 –13000 12500 –16000 10400 – 2100 10400 –12100 12500 –146008 750 900 7800 –11150 8550 –14400 9200 –15800 8600 –13350 9800 –12800
10 600 720 7200 –12100 9000 –13000 7400 –11700 6900 –11400 8300 –1160012 500 600 5800 –10200 7400 –12800 6050 –10600 5800 –10200 6500 – 980014 429 514 4600 – 9500 5600 –10150 4300 – 9300 4200 – 8500 5100 – 8700
DIG 181 10 600 720 – – 12200 –18700 13800 –18700 13600 –2110012 500 600 – – 11200 –15450 11200 –15450 11700 –1560014 429 514 – – 8700 –13500 7950 –13000 9700 –1300016 375 450 – – – 7600 –12000 8700 –1220018 333 400 – – – 6600 –11400 7850 –11800
DIG 191 10 600 720 – – – 19400 –25700 22000 –2780012 500 600 – – – 16000 –22700 16300 –2330014 429 514 – – – 14800 –19700 15200 –2120016 375 450 – – – 12900 –16900 13900 –1830018 333 400 – – – 11100 –15400 13100 –16400
Voltage 3.3 kV 4.16 kV 6–6.6 kV 10–11 kV 13.8 kVFrequency 50 Hz 60 Hz 50 Hz 60 Hz 50 Hz 50 Hz 60 HzFrame size No. of poles Speed rpm Speed rpm Rating (kVA) Rating (kVA) Rating (kVA) Rating (kVA) Rating (kVA)
Specification to German IndustrialStandards DIN – EN60034, VDE 0530, IEC 34
3.2
EnclosureIEC 34-5 DIN VDE 0530 - 5
Standard IP 23. Higher types of enclosuresuch as IP 43, IPR 44, IPR54, IP 44 and IP 54 canbe supplied on request; seeSection 5.6 for further details.
3.3
Cooling methodIEC 34 - 6, DIN VDE 0530 - 6
Standards are:IC01/IC0A1,IC11/IC1A1,IC21/IC2A1,IC31/IC3A1, IC616/IC6A1A6, IC81W/IC8A1W7.In cases where special enclosures are asked for,we can adapt the coolingmethod as appropriate.
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Definition of the alternator
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3.1
Basic technical data
Rated power: See listed ratings
Rated power factor: cos phi 0.8
Rated voltage: 3...15 kV
Rated frequency: 50 Hz resp. 60 Hz, special frequencies available on request
Coolant temperature: 40° C (VDE)
Installation altitude: ≤ 1000 m a sl (VDE)
Enclosure: See 3.2
Cooling method: See 3.3
Design: See 3.4
Deviations from the abovedata and VDE 0530, in or-der to adapt the alternatorsto suit the client’s specific requirements, conditionsand specifications, can beundertaken on request. This includes different typeclassifications in relation torated power from those shown in the listed ratings.Alternators can be built tocomply with internationalguidelines such as BS 4999,CIE 2/3, NF 51100, NE-MA and to marine classifi-cation regulations as in Section 5.5.
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B 3IMB 3IM 1001
B 3/B 5IMB 35IM 2001
B 20IMB 20IM 1101
B 20/B 14IMB 24
B 20/B 5IMB 25
B 16IM 1305
B 2IM 1205
V 1IMV 1IM 3011
3.4
DesignIEC 34 - 7 DIN VDE 0530 - 7
We manufacture the DIG 110 and DIG 171 as standard frame sizes inIMB3, IMB 20 and IM 1305 (B 16).Frame sizes DIG 181 andDIG 191 are supplied asstandard in IM 7201 andIM 7211 with two pedestal-type bearings. Other designs are possible.Special mounting dimen-sions can be adapted to suitthe supporting frame of thecomplete machine assembly.
Design B3 B3/B5 B20 B20/B14 B20/B5 B16 B2 V1 B3/B14 D9 Special design
Code I IMB IMB IMB IMB IMB _ _ IMV IMB _3 35 20 24 25 1 34
Code II IM IM IM IM IM IM IM IM1001 2001 1101 1305 1205 3011 2101 7201
DIG 110to ● ● ● ● ● ● ● ● ● ●DIG 156
DIG 163 ● ● ● ● ● ●DIG 171
DIG 181 ● ●DIG 191
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Mechanical features
4.
Shaft
External bearing cap
Grease regulation disc
Antifriction bearing DE
Internal bearing cover
Bearing plate, DE
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Bearing plate, NDE
Antifriction bearing NDE
Rectifier cover
Rectifier support
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Shaft
Labyrinth seal
Sleeve bearing, DE
Sleeve bearing shell
Lubricating ring
Sleeve bearing cap
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Bearing plate, DE
Fan
Stator housing
Main alternator stator
Main alternator rotor
Stator exciter
Rotor exciter
Bearing plate, NDE
Sleeve bearing, NDE
Rectifier cover
Rectifier support
Fan
Stator housing
Main alternator stator
Main alternator rotor
Stator exciter
Rotor exciter
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Antifriction bearing design
Sleeve bearing design
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4.1
Construction
The alternator consists of amain internal-pole alternatorand an external-pole exciter.On DIG 110 to 171 alter-nators rated for voltages of≤ 11.5 kV, power is sup-plied by an auxiliary exciterwinding in the primary sta-tor to the voltage regulator. For rated voltages > 11.5up to 15 kV, an auxiliary exciter takes over this task.
For DIG 181 and DIG 191frame sizes, we use – depending upon the area ofapplication – an auxiliaryexciter or an auxiliary exciter winding.
Special versions are pro-duced to customer’s order.
4.2
Stator
The stator housing, which isof welded construction, con-tains a stator core made upof low-loss dynamo steelsheets, pressed together bymeans of pressure plates toform a compact unit. The resulting rigid constructiontakes the specific operatingconditions of diesel-electricunits into consideration.
The stator winding complieswith temperature class F inaccordance with GermanIndustrial Standard DIN EN 60034 – 1 and VDE 0530 – 1.
The winding overhangs andconnections are supportedby fastening elements andfirmly linked by mechanicalmeans to guard against loads caused by electro-dynamic forces.
4.3
Rotor
The main salient-pole rotoris made up of metal sheetsor steel plates pressed together. A copper dampercage is installed as standardand electrically connectedto the pole shoes and frompole to pole.The main salient-pole rotorwinding is made from
copper profile and protectedagainst deformation causedby centrifugal forces by sui-table and generously-sizedcomponents. The exciter ro-tor consists of dynamo steelsheets with the three-phasewinding incorporated intoits slots.
The rotor windings complywith temperature class F inaccordance with GermanIndustrial Standards DIN EN 60034 – 1 andVDE 0530 – 1. Standardbalancing of the rotor is carried out according to VDE 0530 / IEC 34 – 14with half key. Other shaftdesigns can be supplied atcustomer’s request.
4.4
Bearing plates
DIG 110 to DIG 171 frame sizes are fitted withwelded or cast iron bearingplates. The alternator feet are mounted in close proximityto the bearings, and are ofsuitable size and shape inorder to guarantee a particu-larly rigid foundation. In the DIG 140, 150 and156 frame sizes the alter-nator’s mounting feet together with the bearingplates form a combinedhousing component. In theDIG 181 and 191 frame sizes the pedestal-type bea-rings are located on a platform bolted on to themachine’s frame. As a resultthe stator and rotor form anintegral unit, which can betransported without any problem and set into a suitable foundation by means of the appropriate lifting gear.
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4.5
Bearings
The standard bearings inthe DIG 110 to 156 framesizes are of antifriction design, with an expectedservice life of at least30,000 hours for stationaryoperation. The DE is equipped with roller bearings and the NDEwith either deep-groove ballbearings or these bearingscombined with roller bear-ings. All bearings are suitable for regreasing andhave a grease volume con-trol system. Whereas thesetypes of alternator can besupplied at extra chargewith sleeve bearings, theDIG 163 to DIG 171 arealways supplied with sleeve
bearings flange-mounted tothe bearing plates, and fitted as standard with a lubricating ring for self-lubri-cation. Depending upon theapplication it may be neces-sary to provide forced oil lubrication or water cooling.The DIG 181 and 191 frame sizes are suppliedwith pedestal-type sleevebearings on the DE andNDE. DIG alternators ofdual-bearing design are always fitted with a fixedbearing and a floating bearing. If antifriction bea-rings are used, the fixedbearing is at the NDE. With plain bearings, it is atthe DE. DIG alternators ofsingle-bearing design havea floating bearing at theNDE. Appropriate fasteningelements ensure that all bearings are protected du-ring transport. Similarly, forreasons of safety, all sleevebearing alternators are made ready for transportwithout oil.
4.6
Terminal boxes
The main terminal boxes aremounted on top or at the si-de of the alternator in accor-dance with the customer’s re-quirements and enclosed toIP54 standard with the po-wer cable outlet at the stipu-lated point. Of the standarddesign’s four terminals, threeare for the U1, V1 and W1power outputs and one forthe star-point connection tothe three U2, V2 and W2windings. If necessary, forexample in order to installcurrent transformers for diffe-rential protection and mea-surements, a larger terminal
box can provided. Currenttransformers installed by AvK / KWK have a copperbusbar which forms thefourth terminal (N). Depending upon the size ofthe alternator, the low-volt-age terminals are located either on the bearing platesat NDE or in a separate terminal box on the statorhousing. Regulator, tempera-ture sensors, secondary current transformer outputs,exciter current measuringleads, heater and similarequipment can be connectedhere. Heating terminalswhich remain live when thealternator is shut down areof safe-to-touch design.
5.3
Relation between power and instal-lation altitudeCharacteristic curve 5.3
As an increase in altitude affects air density and as a result the air’s ability toabsorb heat, it is necessary either to reduce the poweror select a larger alternator.
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5.1
Standard conditions
The listed ratings refer toVDE standard conditions,i.e.:Coolant temperature = 40°CInstallation altitude ≤1000 metres above sealevel, and in accordancewith AvK standard:Enclosure rating IP 23Cooling method IC 01
5.2
Relation between power and coolanttemperature:Characteristic curve 5.2
The decisive factor here isthe winding’s temperature limit. A reduction in coolanttemperature < 40°C will result in an increase in po-wer, an increase in coolanttemperature > 40° C in a power reduction. The characteristic values ofthe selected alternator, forexample reactances, applyin all cases to the pre-definedpower rating (SN).
Derating factors
5.
∂ [°C]
Relation between power and coolant temperature Characteristic curve 5.2 Relation between power and installation altitude Characteristic curve 5.3
5.5
Marine classification
Owing to the fact that cool-ant temperature is higherand the permissible tempe-rature rise lower than ac-cording to the regulations pertaining to land-basedoperation, it is necessary toreduce the power or to increase the size of the alternator.
The adjacent table is appli-cable for permissible tempe-rature rises with design andutilisation in accordancewith temperature class F.Please provide us with details if types of enclosureare higher than IP 23 andadditional requirements apply.
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Classification regulations CT Temperature rise SNom/SType
°C K
Germ. Lloyd 45 100 0,96
RINA 50 90 0,925
American Bureau of Shipping 50 95 0,96
Bureau Veritas 50 90 0,925
Det Norske Veritas 45 90 0,925
Lloyds Reg. of Shipping 45 951) 0,925902)
Register USSR 45 95 0,96
Information: DIN VDE 0530 -1Coolant temperature 40° C, temperature rise 105 K for ≤ 5 000 kVA
temperature rise 100 K for > 5 000 kVA1) ≤ 5000 kVA2) > 5000 kVA
5.4
Relation between power and cos phi :Characteristic curve 5.4
The under-excited range cosphi 0 – 1 is limited at:
● single operation main-taining the rated voltageby the voltage regulator
● parallel operation by stability against desynchronisation
The over-excited range is limited between:
● cos phi = 1 - 0.8 by the prime mover’s power
● cos phi = 0.8 - 0 by the permissible rotortemperature rise.
Relation between power and cos phi Characteristic curve 5.4
Limited by alternator
Limited by prime mover
under-excited over-excited
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5.6
Higher types of enclosure
Design and electrical mea-sures are laid down duringthe project stage. The ratingplate contains details of the enclosure and the ratedpower.
5.6.1
Enclosure IP 43
The IP 43 enclosure requiresthe provision of a dust filter,which increases air resis-tance so that power is re-duced by 5 %. Temperaturesensors in the alternator,which are connected to a dripping device on theswitchgear, detect any unacceptable rise in windingtemperature when the dustfilter is due for cleaning.
5.6.2
Enclosure IPR 44 or IPR 54
An additional advantage –in addition to the higherprotection level – is the factthat the required cooling airis discharged from the instal-lation area by air ducts,which also helps to reducethe noise level. The alter-nator’s air inlets and outletsare designed to facilitatethe attachment of intake anddischarge ducts. The per-missible pressure loss in theducting must be co-ordina-ted with the manufacturer.
5.6.3
Enclosure IP 44 or IP 54
These types of enclosure require the use of heat ex-changers. Of primary signi-ficance for the alternator isthe temperature of the coo-ling air leaving the coolerand entering the alternator.
● Water-cooled heatexchanger:In a conventionally design-ed heat exchanger, thecooling air temperature asit enters the alternator is15° C higher than thewater temperature when itenters the exchanger. The power variation canbe seen in characteristiccurve 5.2. No power reduction results from theincrease in the cooling circuit’s air resistance.
● Air-cooled heat exchanger:In this case, the tempera-ture of the air leaving thecooler and entering thealternator is higher thanthe outside air by theamount represented bythe temperature drop inthe heat exchanger. In aconventionally designedheat exchanger, the coo-ling air temperature as itenters the alternator is15° C higher than the airtemperature when it entersthe cooler. The power reduction canalso be seen in character-istic curve 5.2. Increasedair resistance will result ina power reduction if thealternator’s cooling systemhas been designed in an extremely compactmanner. For this reason, it is recommended to undertake a precise analysis of requirementsand to select the relevantmachine rating in eachcase.
6.1.2
“COSIMAT N+” voltage regulator
The “COSIMAT N+”, astandardised module, is set up on the alternator inthe test field and a func-tional test is carried out. Voltage is supplied to the regulator via an auxiliarywinding in the primary rotoror an auxiliary exciter machine.
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6.1
Operating principle
Electrical functions
6.
Main machine
Exciter machine
Auxiliary exciter machine
Current transformer
Instrument transformer
Set-point potentiometer
G1
G2
G3
T6
T24
R1
Main machine
Exciter machine
Auxiliary winding
Current transformer
Instrument transformer
Isolating transformer
Set-point potentiometer
G1
G2
G3
T6
T24
T32
R1
With auxiliary exciter machine
With auxiliary exciter winding
Voltage regulator
Voltage regulator
6.1.1
Alternator
The auxiliary exciter machi-ne/auxiliary exciter windingG3 supplies the brushlessthree-phase AC exciter G2with current via the voltageregulator’s control element.The voltage generated bythe three-phase exciter rotorwinding is rectified in athree-phase silicone-diodebridge circuit and fed to therotor of alternator G1. Voltage regulation of the primary alternator at fluctuat-ing loads is carried out byaltering the exciter current inthe G2 winding by usingthe voltage regulator’s transistor control element.
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In order to record unequalphase voltages arising during asymmetrical loads,the alternator voltage ismeasured over three phases.The voltage regulator usesexciter current IK1 in exciter’s winding G2 tokeep the voltage across themain machine’s terminals ata constant level. A special leaflet describesthe COSIMAT N+ voltageregulator in greater detail. The COSIMAT N+ is alsoavailable with additional regulators and modulesshould special operatingfunctions be required.
The control signals for thefollowing functions are fedin via the terminals on theCOSIMAT N+:
● cos phi regulation/ balancing
● reactive power control/ balancing
● extension of adjustmentrange
● automatic stand-by changeover
● U/f control● current-limiting control ● exciter-limiting control ● cable compensation
These devices are descri-bed in additional leaflets.
6.2
Self-excitation, de-excitation
6.2.1
Self-excitation
● For alternators ≤11.5 kVwith an auxiliary exciterwinding, self-excitation is by way of permanentmagnets in the exciter.
● For alternators > 11.5 kVwith auxiliary exciters,self-excitation occurs viathe natural rotor reman-ence and the optimisedvoltage of the auxiliaryexciter’s stator.
In special cases, excita-tion can be obtained byapplying an external voltage of approximately10 V DC (positive pole tothe I terminal).External excitation shouldnot be active when thealternator is at a standstill.
● For alternators with auxili-ary windings, this voltageshould be applied to theexciter’s I1 - K2 terminalsduring the run-up to the rated speed. A blockingdiode is needed.
● In alternators with auxili-ary exciters the externalvoltage should be brieflyapplied to terminals I2 -K2 of the exciter. The alternator must be runningat rated speed.
6.2.2
De-excitation
● The current in the exciterG2’s winding IK1 must bereduced to 0 for de-excitation to occur. Forthis purpose, the powersupply to the regulatormust be disconnected byremoving the jumpers orby resetting a switch asshown in the circuit dra-wing. Disconnection mustalways be on the controller’s input side at UH1 – UH1’ andWH1 – WH1’. The switching contactsmust be rated for 10 A and 220 V AC.
● Please comply with the instructions on the relevantcircuit diagrams.
Caution:The alternator generates aremanence voltage of app.15 % of UN after de-excita-tion. This value is in excessof the permitted contactvoltage limit!
6.3
Voltage and frequency
AvK alternators for voltagesup to 15 kV are built to thespecifications laid down byGerman VDE 0530 andother national standards for50 or 60 Hz frequencies.However, our versatility enables us to provide othervoltages and frequencies onrequest.
6.3.1
Voltage adjustmentrange
DIG alternators are suppliedas standard with a set-pointadjuster, which is installed inthe switchgear for ease ofuse. As a result, the voltageis infinitely adjustable. In accordance with Germanstandard VDE 0530, the adjustment range is ± 5 %of the rated voltage and canbe extended ±10 % for oper-ational testing of switchgearcomponents and synchroni-sation. The resistance of thepotentiometer’s wires can bedisregarded if the conven-tional distance between theunit and switchgear is notexceeded. Screened cablemust be used for the con-nections. The voltage range between no load and full load in accordance withGerman VDE 0530, IEC 34standards is (0.95 - 1.05) xUN with the limitations aslayed down in theese standards.
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6.3.3
Transient voltage be-haviour
See oscillogram 1Load applicationSee oscillogram 2Load shedding
The transient voltage vari-ation under fluctuating loadis dependent on alternatorG1’s reactance voltagedrop.
The magnetic circuit and the winding ratings are optimised for low transientvoltage fluctuations.
The relative current surgeand power factors are theexternal influencing factorsfor the transient voltage fluctuations. Application offull load at cos phi 0.8 results in a transient voltagedrop of app. 18...25 %.The smaller value applies tomachines with 1500 rpm,the large value applies toslow-running machines at500 rpm. The transient voltage fluctuation is slightlylower at base load thanwhen the alternator is running off-load.
The voltage-time characteri-stic is governed by the alter-nator G1’s time constants,the exciter G2, the regula-ting system and the externalinfluence exerted by a dynamic drop in speed. The generously sized excitersystem achieves short tran-sient recovery times, owingto the excessive excitationeffect provided by the powersupply during the recoveryperiod up to nominal voltage.
Transient recovery time, depending on alternator size, is 0.5...0.8 seconds.
Oscillogram 1 / Load application
Oscillogram 2 / Load shedding
Alternator DIG 150l/8 3300 kVA 11kV 50 Hz 750 rpmDisconnection of 1000 kVA cos phi = 0.1
Alternator DIG 150l/8 3300 kVA 11kV 50 Hz 750 rpmLoad application 1000 kVA cos phi = 0.1
6.3.2
Steady-state voltageperformance
The voltage accuracy is ± 0,5 % to ±1 % subject tothe following conditions/influencing values:
● No load to nominal loadat cos phi 0.11) … 1
● Machine cold or warm
● Drop in speed of app. 3 %
1) This refers to the regulating char-acteristic. The thermal rating forcontinuous operation is for cos phi0.8. The usual operating range is cos phi 0.8 … 1.
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6.4
Currents
6.4.1
Asymmetrical loads
The alternator’s electrical layout also permits an asym-metrical load.
● Asymmetrical loads without loading the otherphases are permitted inthe following cases:a) 60 % of the rated cur-rent measured betweenphase – neutralb) 35 % of the rated current measured betweenphases In this case the ratio of thenegative-phase sequencesystem I2 to the rated current IN is 20 % and distinctly higher than theGerman VDE specifi-cations.
An asymmetrical load cau-ses voltage asymmetry andadditional losses, which have a distinct effect on thedamper cage’s rise in tem-perature. The load shouldtherefore be allocated to thethree phases in as symmetri-cal a manner as possible. The voltage asymmetry∆UUN is app. ±6 % in loa-ding case a. (VDE 0530)The voltage asymmetry∆UUN is app. ±4 % in loa-ding case b. (VDE 0530)
● If additional currents areapplied to the other pha-ses, the values of the posi-tive-, negative- and zero-phase sequence systemsmust be recorded analyti-cally or graphically in order to ascertain the actual alternator load.
The current may not ex-ceed the rated current inany of the winding pha-ses in the alternator andthe relationship of the negative-phase sequencesystem I2 to the rated current IN must remain below 20 %.
● AvK recommends limitingI2 / IN for protection ofthe overall system to ≤ 0,08 in accordancewith the applicable standards.
6.4.2
Overload
● In accordance with Ger-man VDE 0530 standard,the alternators must be able to withstand 1.5xthe nominal current for aperiod of 30 seconds.
● To match the requirementsfor internal combustion engines an overload of1.1 x nominal current isprescribed for 1 hour within an overall 6-hourperiod.
● The generously sized exciter equipment allowsa short-time overload of1.8 x the nominal currentfor a period of 10 secondswithout an abnormal dropin the nominal voltage.This overload capabilityis, for example, availablein form of starting currentfor asynchronous motors.
6.3.4
Voltage waveform
The geometry of the mag-netic circuit and the windingfactor selection of the statorwinding combine to gene-rate a sine-wave voltagewaveform.
The conventional definitionsare as follows:
● Telephone harmonic factor “THF”
The requirement laid downby the German VDE 0530standard is easily main-tained.
● Harmonic content
The harmonic content is ≤ 2 % measured betweenphases at no load up to nominal load and powerfactor of cos phi 0.1… 1under symmetrical and linear loads.
The winding is optimised inorder to keep the 5th and7th harmonics measuredbetween the phases as lowas possible. The 3rd har-monic however, dependingon load, increases from≈ 2 % to ≈ 10 % measuredbetween phase and neutral.This does not occur in star
connections measured be-tween phases, as the phasevoltages equalize eachother.
A specially custom-designedwinding reduces the harmo-nic content below 3 % andthe percentage of individualharmonics to less than2 % – also for voltage curve between phase and neutral.This however necessitates a power reduction of app. 10 %.
18
Oscillogram/peak short-circuit current
Short-circuit current characteristic for a short circuit between three phases of a DIG alternator 130g/6 1450 kVA 6,6kV with a nominal current of 127 A, IKD3ph
= 419 A
6.6
Emergency operation
In order to satisfy certain safety requirements, it ispossible to operate the alter-nator by means of emer-gency manual controls inthe event of a voltage regu-lator breakdown, or it canbe switched over to a stand-by regulator either manually or automatically.
6.4.3
Short-circuit beha-viour
● The relevant machine parameters are designedso that the peak short-circuit current is low. Depending upon machinesize, it decays to the su-stained short-circuit currentlevel within a period of0.3...0.6 seconds.
● The relevant componentsare suitably dimensionedto ensure that in the caseof a three-phase short-circuit between terminals,the alternator supplies 2.5 to 4 x the nominalcurrent for a period of 3 seconds. In the event ofa two-phase short-circuitbetween terminals, the sustained short-circuit current rises by a factor ofbetween 1.4...1.7. This ensures selectifity ofthe protection devices .
The range IK = (3...6) x INfor example is generallyrequested by marine clas-sification societies.When the short-circuit iscleared the resulting exci-tation leads to a transientvoltage increase whichalmost reaches ceilingvoltage. This voltage in-crease is also possibleduring certain interruptionsto the voltage regulatorsystem. Suitable protec-tive measures for the con-sumers must be providedfor in the switchgear.
6.5
Harmonic load
Current rectifiers, as con-sumers with non-linear loadcurrents, cause harmonics tooccur in the voltage curve.In order to minimise the re-sulting alternator and systemlosses, and to ensure thatthe operation of all electri-cal equipment connected tothe system is not compro-mised, the harmonic contentof the voltage curve shouldbe kept as low as possible,see also Section 6.3.4.
For this purpose, a low sub-transient reactance xd”is required. This can beachieved by using a dampercage of suitable dimensions.
If a very high proportion ofthe load is caused by rec-tifiers, it may be necessaryto enlarge the size of alter-nator and use a speciallydesigned magnetic circuit.This automatically results inan increase in the peakshort-circuit current.
The measures required atthe alternator are dependentupon the relative non-linear
load, enforced current har-monics at the consumer endand the permissible outputvoltage distortion factor.
19
6.6.1
Emergency manualoperation
The current delivered by thepower supply is fed to theexciter winding I1 – K1 ofthe exciter G2 via a variablevoltage transformer with arectifier connected in series.A rheostat of app. 300 Wcan also be used in placeof the variable-voltage trans-former. Manual compensa-tion to correct exciter outputproves to be extremely diffi-cult, particularly in cases ofsudden peak loads. Emergency manual operationis therefore only possiblewhen an isolated networkhas negligible fluctuating loads or in system operationparallel with the mains.
6.7
Star point connection/neutralcurrent
DIG alternators are rated inaccordance with GermanVDE 0530 – 1 standard.They can be operated withdirectly earthed or non-earth-ed neutral points. The typeof neutral earthing is deter-mined by the network’s pro-tection specifications andnot by the alternator.
Here is some information on the various ways to eartha neutral point (direct earthing):
a) Impedance earthing (solid earthing):
When earthing severalpoints, e.g. an alternatorneutral point and trans-former neutral point or several alternator neutralpoints, excessive currentscirculating in the earthingsystem generated by harmonics – mainly of
odd-numbered orders –cause thermal overloadson the windings and, inparticular, the neutral terminals. It may be necessary to use neutralreactor coils to reducethese currents.
In the event of a phaseshort-circuiting to earth,extremely high currentscan occur. If the windingssuffer any damage thehigh ground fault currentscan lead to burning spotsin the laminations. In order to ensure that nodamage can occure, differential protection isstrongly recommended.
b) High-resistance earthing:
As a rule, the limited currents arising during aphase short-circuit toearth endanger neitherwindings nor cables. As the neutral conductor’searthing resistance isusually rated for short-timeoperation only, it is ad-visable to consider the installation of selectiveprotection devices.
c) Non-earthed neutralconnection
This refers to a non-eart-hed network system, i.e.not only the alternator’sneutral point is unearthed,but the entire network isoperated without neutralpoint earthing. The following section describes the effects onthe alternator, not whathappens within the network.
In the event of a short-cir-cuit to earth in an uneart-hed network, it is possiblethat a phase is shorted to earth for a long periodof time. The windinginsulation of the alternatormeasured to ground thenis subjected to a voltageingreased by factor √3. In accordance with German VDE 0530 – 1 standard this situationmay not extend beyond a certain period.
If it is anticipated that themachine is to be operatedfor longer periods undersuch conditions then thewinding must be ratedwith a suitable (higher) insulation level.
The entire control unit – primary control, stand-bycontrol, manual or automaticchangeover device – must be mounted in the switchgear.
6.6.2
Stand-by control
Using stand-by control eliminates the inherent dis-advantages of the emergen-cy manual operation owingto the fact that after switchingto this control the alternatorcan continue to operate inan unaltered condition.
7.1
General
Parallel operation of a required number of gen-setsallows an optimum utilizationand increased efficiency. Furthermore, the reliability of the system is improved because at breakdown ofone gen-set the remainingsets will take the load, properload management provided.
20
Parallel operation
7.
7.4.1
Voltage droop
The terminal voltage is lowe-red relative to the reactivecurrent. The identical voltage droop is requiredfor maintaining the reactive-load distribution in proporti-on to the output.
The voltage droop’s cos phirelationship ensures that inparallel operation with themains and when the mainsvoltage fluctuates any apparent change in outputis kept to a minimum.
This method can be used up to a mains-voltage fluctuation of ± 2 %.
The voltage droop at nom-inal current is as follows:
0 % at cos phi = 11.3 % at cos phi = 0.91.8 % at cos phi = 0.83 % at cos phi = 0
7.4
Stationary operation/ load distribution
● Active load distribution is governed by the primemover’s speed charac-teristic.
● Reactive-load distributionis governed by the alter-nator’s voltage characteri-stic.
The following methods of reactive-load distributionmay be used:
7.3
Start-up synchronisa-tion for isolated par-allel operation
This function can only beused on machines of the same type and necessitatessimultaneous starting of thediesel driven units. The alter-nators are electrically inter-connected at standstill. Asspeed increases, the alter-nators are self-excited andattempt to synchronise witheach other. In order that theequalizing currents whichflow in the primary circuit
UVW until synchronisationis reached are not excee-ding the rated current, theexciter current is to be limi-ted when using an externalvoltage (12 V DC) for initialexcitation. A blocking diode is used to connect the12 V battery to the regulator.Apart from this, the regulatorsupply is to be interrupted inaccordance with 6.2 “De-excitation” as the machine runs up to speedand released again after reaching the rated speed.The voltage subsequentlyapplied to the regulator atterminals I1 - K1 rises abovethe battery voltage. A blocking diode in the battery supply lines preventsreturn flow to the battery,which can then be disconnected.
7.2
Conditions for paralleloperation
The alternators to beconnected to the mains oroperated in parallel mustcomply with the synchroni-sation conditions, i.e. theymust be identical with re-gard to the following criteria:
VoltageFrequencyPhase sequencePhase angle
Permissible tolerances priorto full-load connection areas follows:
Voltage tolerance5 % of UN
Frequency tolerance2 % of fN
The frequency tolerance applies to conventional
diesel-driven generating sets.A lower value is permissiblewhere additional flywheelsare used.
In order to prevent synchro-nisation errors arising, forexample due to the actionsof unqualified operatingpersonnel, it is advisable toinstall a synchronising relayin the switchgear which only releases the circuitbreaker after the prescribedsynchronising conditions have been met with.
After paralling, the activeand reactive load distributionmust be balanced.
21
7.6
Oscillations
Periodic fluctuations in ac-tive and reactive load arecaused by the irregular torque variations of internalcombustion piston engines.In order to attenuate thesefluctuations in parallel operation, a damper cageis installed in the alternatoras standard.
7.5
Parallel mains operation
Since in the majority of cases the mains has a muchhigher short-circuit capacitythan the alternators, thenumber of units running inparallel is irrelevant so thatno significant influence isexerted. As a result, almostall voltage fluctuations aredetermined by the mains.
In the event of a mains vol-tage fluctuation of ∆U ≤ 2%the voltage droop in accor-dance with 7.4.1 can beused.
In the event of a mains vol-tage fluctuation of ∆U > 2%a cos phi regulator is usedwhich automatically adjuststhe alternator voltage to themains voltage by influen-cing the exciter voltage.This ensures that the pre-setpower factor remains con-stant in the event of mainsvoltage fluctuations or if thealternator is subjected to various loads. If a certainpower factor is required atthe mains interface point,the current transformer effec-ting the cos phi regulator
must be located at this point.It is advisable to install anexciter current limiter in orderto prevent the exciter circuitfrom being overloaded. It limits the exciter current to thevalue of the nominal powerrating at cos phi = 0.8. It is further possible to influence the reactive powersupply by using a reactivepower regulator. Permissibleincreases in voltage and frequency fluctuations arestipulated by the applicableGerman standard DIN VDE 0530 - 1, Section12.3, Figures 10 and 11.If voltage and frequency deviate from the nominal values, the temperature atconstant nominal power willincrease. This reduces theservice life of the windingand as a result that of theoverall machine. Voltage increases cause temperaturerises in the iron of the mainmachine which are transmit-ted to the winding. Drops involtage cause the current torise and, as a result, thewinding temperature in-
creases. Since the service life of the winding is always compromised if the temper-ature in the relevant temper-ature class is exceeded, it isadvisable to prevent longoperating periods at the extreme limit of the range A in German DIN VDE 0530 – 1. This will be en-sured if the machine is builtand operated in accordan-ce to the operating dataknown during project stage.
7.4.2
Power factor regulation
This method is used for parallel operation with themains where heavy voltagefluctuations occur. A cos phi regulator locatedin the alternator or the switchgear energises the alternator’s COSIMAT N+regulator in order to maintainthe pre-set power factor, i.e.the alternator voltage is automatically adjusted tothe mains voltage.
Proven experience results ina factory setting for ensuringstable parallel operation of3 % at nominal current andcos phi 0.1. For alignmentpurposes with other makes,the droop can be infinitelyadjusted from 0 % - 6 % ofthe nominal voltage.
22
Features of the medium voltage winding
8.
Outer mica sleeve
Mica film
Polyester film
Profile copper
8.2
Design and manufacture
The systematically developedinsulation structure, the ma-nufacturing process and thematerials used are describedbelow.
The basic material for thecoils is profil copper wrapped in mica film. Thecoils made from this areshaped by expansion andtrimming during installationin the stator slots.
The insulation of the coillimbs – the area in whichthe stator slots are located –is carried out subsequentlyusing temperature class “F”
high-grade thermosetting mica film. A tight windingaround the coil ensureshigh-quality insulating properties.
This insulating material con-sists of three components: ● glass fibre as the base
material ● high-grade mica film as
the insulating material● epoxy resin as the
binding agent.
Coil-limb insulation thicknessis determined by the nomi-nal voltage.
A special hardening pressoperating under high pres-sure at a temperature of be-tween 160° C - 180° C isused to harden the coillimbs uniformly and givethem their exact shape forinstallation in the stator slots.
To ensure uniform coil production quality, they aremonitored by measuring theloss factor in relation to thevoltage. The test is carriedout in accordance with German VDE 0530 – 1standard. The initial- and rise-time values are far
below maximum permittedlevels. Impulse voltage testscarried out on master coilsmonitor the strand insulationin accordance with GermanVDE 0530 -15, IEC 34 -15.Tests are subsequently carried out at regular inter-vals on the master coils, independent of any orderspecification. In addition tothis, during these tests animpulse voltage test is carried out on the main insulation.
Voltage tests according tothe process instruction arecarried out on the finishedcoils after they have beeninserted into the stator. Afterinterconnecting the coils toform a winding, each phaseis subjected to a voltage testin accordance with GermanVDE 0530 - 1, IEC 34-1.
Depending upon the nomi-nal voltage, the coil headsare insulated by overlap-ping them with several layers of various integrated-mica glass-fibre tapes.
8.1
General
AvK builds synchronous machines for the below listed nominal voltages and outputs:
Power range:
3,3 kV up to 13000 kVA
4,16 kV up to 16000 kVA
6,0 – 6,3 – 6,6 kV up to 18500 kVA
10,0 – 10,5 – 11,0 kV up to 26000 kVA
13,8 kV up to 27800 kVA
15,0 kV up to 20000 kVA
Mainly synchronous genera-tors are produced. Specialvoltages in the ranges between 3.3...15 kV canbe realised by AvK upon request. The design andmanufacture follows the applicable standards for electrical equipment. Special requirements will beconsidered upon request.
In order to ensure that thehighest degree of operatingreliability is maintained un-der the most various opera-ting conditions, insulatingmaterials have been coordi-nated and developed overmany years in conjunctionwith leading manufacturersin this area. Large numbers
of AvK alternators are in useby satisfied customers allover the world. They repre-sent ample proof of the outstanding standard of AvKmedium voltage technologyin the field of brushless alternators.
23
Factory tests
9.
9.1
Standard tests
1. Cold resistance measurements
2. Residual voltage measurement
3. Voltage symmetry
4. Phase-sequence test
5. Load characteristic withcos phi = 0.1
6. Set-point potentiometerrange/Voltage adjustment range
7. Voltage regulator
7.1 Voltage regulator adjustment
7.2 Underspeed protectionadjustment
7.3 Parallel operationadjustment
8. Short time overloadwith cos phi = 0.1 or at short-circuit
9. Winding test
10. Overspeed test at 120 % nominal speed
11. High voltagemeasurement
12. Insulation resistancemeasurement
13. Adjustment of additionalvoltage regulator modules
Final acceptance:
General construction
Inspection of component sizes, cable inspection,identification, circuit diagram, nominal data,space heater, temperaturesensors etc.
9.2
Special tests (at extra charge)
1. No-load characteristic
2. Short-circuit characteristic
3. Efficiency measurement(summation of lossesmethod)
4. Temperature-rise test
5. Noise-level test
6. Load connection anddisconnection
7. Harmonic content analysis
8. Peak short-circuit test
9. Sustained short-circuitcurrent measurement
10. Vibration measurement(kardan driven or at motor operation)
11. Rotor leakage test withrotor removed (inductor)
For voltages greater than4.16 kV, measured betweenphases, each coil limb isprovided with coil-side cor-ona shielding for the lengthof the laminated core, whichprevents glow dischargeand destruction of the coil-limb insulation withinthe laminated core.
The coil-side corona shielding combines withoverhung corona shielding,which uniformly reducesfield strengths in the slot exitarea towards the coil headin order to keep damagingfield-strength fluctuations toan acceptable level.
After having been woundcompletely, the stator under-goes heat treatment in ac-cordance with the specifica-tions of the insulating-material manufacturers. The material then hardensand fuses together to form anon-porous, absolutely air-tight insulating cover whichis impervious to moisture.
In order to maintain controlover magnetic forces duringsudden peak loads and, in
particular, in the event ofshort circuits, the coil headshave been mechanically fixed by means of suitablydimensioned fastening elements.
● The straight sections of the coil limbs protrudingfrom the slots are mutually supported by insertedwedges, which are encapsulated in resin.
● Depending on their lengthand projection, the coilheads are bound togetheron the inclined section ofthe coil head projectionby one or more so-called“polyester cords”. Thesepolyester cords then har-den during the previouslymentioned stator’s heattreatment. In doing so,uniform shrinkage occursso that the individual coilheads combine to form asingle winding overhangof greater rigidity, yet more compact size.
● The geometrical design of a ring-type bondingmade of insulating materialon the winding overhang serves to ensure optimizedrigidity of the windingoverhang.
These measures combine to prevent any movement orindeed deformation of thewinding overhang evenwith extreme loads duringalternator operation.
Subject to technical modifications
PB D
IG 4
0498
GB
AvK Deutschland GmbH & Co. KGSteinstraße 80 · D -85051 Ingolstadt (Germany)P.O.B. 10 0651 · D - 85006 Ingolstadt (Germany)Phone +49 841/792 - 0 · Fax +49 841/73000e-mail: [email protected]
Sales:AvK Deutschland GmbH & Co. KGDreieich branchBenzstraße 47- 49 · D -63303 Dreieich (Germany)P.O.B. 10 1128 · D - 63265 Dreieich (Germany)Phone ISDN +4961 03/5039 - 0 · Fax +49 6103/50 39 - 40e-mail: [email protected]
