CT Sizing Calculations

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CT SIZING CALCULATION

BY

DAR

Saudi Electricity CompanyCenteral Region Branch

CH

EK

'D

Y.R

NO

.

A

BY:-

BY:-

DATE:-

BY

DATE:-

BY:-

DATE:-

BY:-

DATE:- AS BUILT BY DATEINDEX PLANT REV.

DWG.CON. SHT.

1 OF 50 A

1/21/2012

THIS DRAWING IS NOTTO BE USED FOR

CONSTRUCTION OFFOR ORDERING

MATERIALS UNTILCERTIFIED AND

DATED

DOCUMENT TITLE DOCUMENT NO. SHEET NO.

132kV CT SIZING CALCULATION FOR A

RIYADH SAUDI ARABIA CONTRACT NO: 11031117/00

CE-267304

CERTIFIED.

C269

JAN - '12

ENG'G. DEPT.

9016 SUBSTATIION

OPRG. DEPT

DESIGNED

DA

TE

JAN

- '12

Y.R

DATE:- JAN - '12

CHECKED

Y.R

JAN - '12

REVISIONS

132kVSIDECTSIZINGCALCULATIONSFOR9016SS

Sr.No DESCRIPTION Sht.No

1 COVERSHEET 1

2 INDEX 2

3 CTDATA 39

4 STSTEMDATA 1011

5 87T1GT(RET670)CTCALCULATION 1213

6 87T2GT(RET670)CTCALCULATION 1415

7 87C1+95C1SGT(REC670)CTCALCULATION 1617

8 87C2+95C2SGT(REB670)CTCALCULATION 1819

9 SGT132kVOCEFCTCALCULATION 2021

10 87C+95C(REC670)132kVREACTORCTCALCULATION 2223

11 87R+95R(REB650)REACTORCTCALCULATION 2426

12 5051+50BF1(BUILTIN)REACTORCTCALCULATION 2728

13 51NR(REF615)REACTORCTCALCULATION 2930

14 BSBC5051+50BF1+50CBF2CTCALCULATION 3132

15 87B+95BDISC(REC670)CTCALCULATION 3334

16 87B+95BCHK(REC670)CTCALCULATION 3536

17 SGT132kVMETERINGCTCALCULATION 3738

18 METERINGGTFEEDERSCTCALCULATION 3940

19 METERINGSPAREOGFEEDERSCTCALCULATION 4142

20 METERINGCAPACITORFEEDERSCALCULATION 4344

21 METERINGSPARESVCBAYCTCALCULATION 4546

22 METERINGREACTORFEEDERSCTCALCULATION 4748

23 132kVBSBCMETERING 4950

INDEX CE267304 2/50


Sr.No CTNo Function RelayType CTPrimary(Amp)

AdoptedTap(Amp)

CTSecondary

CTClassCTKneePointVoltage

CTKneePoint

VoltageAtAdopted

Tap

CTMagnetizingCurrent(mAmp)

CTMagnetizingCurrentAtSelected

Tap

CTResistance(Ohms)

CTResistanceSelected

Tap(Ohms)

1T11CORE3

IPCT+DM(LCC)+EnergyMeter+DSM

ALPHAA3+DSM+IPCT

300025002000160012001000

1000 1 X420035002800224016801400

14008.331012.515.620.825

25653.22.4

22

2T11CORE2

MAIN2PROTN(FUTURE)

300025002000160012001000

1000 1 X420035002800224016801400

14008.331012.515.620.825

25653.22.4

22

3T11CORE1

MAIN1PROTN(FUTURE)

300025002000160012001000

NA 1 X420035002800224016801400

NA8.331012.515.620.825

25653.22.4

2NA

4T12CORE1 BCU+FR

7MD664+FR(

Hathaway)

300025002000160012001000

1000 1 X420035002800224016801400

14008.331012.515.620.825

25653.22.4

22

5T12CORE2

87B(DISCZONE)

REC670 4000 4000 1 X 800 NA 25 NA 6 NA

6T12CORE3

87B(CHKZONE)

REC670 4000 4000 1 X 800 NA 25 NA 6 NA

132kVBayNo=D22(SPARESVCBAY)

CTDATA CE267304 3/50



AdoptedTap(Amp)

CTSecondary


CTKneePoint

VoltageAtAdopted



CTResistance(Ohms)


Tap(Ohms)

Sr.No CTNo Function MeterType CTPrimary(Amp)

AdoptedTap(Amp)

CTSecondary


CTKneePoint

VoltageAtAdopted



CTResistanceAtTap1(Ohms)

CTResistanceAtTap2(Ohms)

1T13CORE3

IPCT+DM(LCC)+EnergyMeter+

ALPHAA3+DSM+IPCT

2000160012001000

8001000 1 X

3500280021001750

14001750

1012.516.72025 20 5432.5 3

2T13CORE2

MAIN2PROTN(FUTURE)

2000160012001000

8001000 1 X

3500280021001750

1400 1012.5

16.72025 5432.5

3T13CORE1

MAIN1PROTN(FUTURE)

2000160012001000

800NA 1 X

3500280021001750

1400 1012.5

16.72025 5432.5

4T14CORE1 BCU+FR

7MD664+FR(

Hathaway)

2000160012001000

8001000 1 X

3500280021001750

14001750

1012.516.72025 20 5432.5 3

5T14CORE2

87B(DISCZONE)

REC670 4000 4000 1 X 800 NA 25 NA 6 NA

6T14CORE3

87B(CHKZONE)

REC670 4000 4000 1 X 800 NA 25 NA 6 NA

132kVBayNo=D17,=D02(

SPARECAPACITOR

BAYS)




AdoptedTap(Amp)

CTSecondary


CTKneePoint

VoltageAtAdopted



CTResistance(Ohms)


Tap(Ohms)

1 T3CORE1

EnergyMeter+DSM

ThroughIPCT

ALPHAA3+DSM+IPCT

16001200800600 800 1 X

2800210014001050 1400

12.516.72533.3 25 4321.5 2

2 T3CORE2MAIN2PROTN(FUTURE)

16001200800600 800 1 X

2800210014001050 1400

12.516.72533.3 25 4321.5 2

3 T3CORE3MAIN1PROTN(FUTURE)

16001200800600 800 1 X

2800210014001050 1400

12.516.72533.3 25 4321.5 2

4 T4CORE1 BCU+FR7MD664+

FR(Hathaway)

16001200800600 800 1 X

2800210014001050 1400

12.516.72533.3 25 4321.5 2

5 T4CORE2 87B(DISCZONE)

REC670 4000 4000 1 X 800 NA 25 NA 6 NA

6 T4CORE3 87B(CHKZONE)

REC670 4000 4000 1 X 800 NA 25 NA 6 NA

132kVBayNo=D01,

=D03,=D07,=D08,=D11,=D13,=D15,=D19,=D12,=D16,=D18,=D20,=D24(SPAREUG&OHLFEEDERS)




AdoptedTap(Amp)

CTSecondary


CTKneePoint

VoltageAtAdopted



CTResistance(Ohms)


Tap(Ohms)

1 T5CORE1

IPCT+DM(LCC)+BCU(LCC)+DSM+

AMR+PQM

DM(LCC)+BCU(LCC)+DSM+

AMR+PQM300 300 1 5P20,30VA NA NA NA NA NA NA

2 T5CORE2MAIN2PROTN(BOX2)

RET670 300 300 1 X 360 360 50 50 1 1

3 T5CORE3MAIN1PROTN

(BOX1)+FR

RET670+HATHAWAY

300 300 1 X 360 360 50 50 1 1


REC670 4000 4000 1 X 800 NA 25 NA 6 NA


REC670 4000 4000 1 X 800 NA 25 NA 6 NA

132kVBayNo=D04,

=D09,=D10(132/13.8kVGTBays)




AdoptedTap(Amp)

CTSecondary


CTKneePoint

VoltageAtAdopted



CTResistance(Ohms)


Tap(Ohms)

1 T7CORE1

DPDM(LCC)+BCU(LCC)+FR+IPCT+ENERGYMETER+DSM


1200600400200 200 1 X

24001200800400 400

8.3316.72550 50 6321 1

2 T7CORE2 50/51N+FR REF615+FR 1200600400200 200 1 X

24001200800400 400

8.3316.72550 50 6321 1

3 T7CORE3 87C+95C REC670 1200600400200 1200 1 X

24001200800400 2400

8.3316.72550 8.33 6321 6


REC670 4000 4000 1 X 800 NA 25 NA 6 NA


REC670 4000 4000 1 X 800 NA 25 NA 6 NA

1 LC11 87R+95R REB650 600400200

200 1 XNOT

AVILABLE400

NOTAVILABLE

50NOT

AVILABLE1

2 LC12 87C+95C REC670 1200600400200 1200 1 X

3 NC11 49(WINDTEMP)

4 NC21 87R+95R REB650 600400200

200 1 X 400 50 1

5 NC22 51NR REF615 400 400 1 5P20,15VA

132kVBayNo=D21,

=D26(132kVReactorBays)

ShuntReactorBushingCTs



Sr.No CTNo Function Meter/RelayType

CTPrimary(Amp)

AdoptedTap(Amp)

CTSecondary


CTKneePoint

VoltageAtAdopted



CTResistance(Ohms)


Tap(Ohms)

1 T1CORE1DPDM(LCC)+BCU(LCC)+EM+DSM

DPDM(LCC)+BCU(LCC)+ALPHAA3+DSM

30001500 3000 1 0.2FS5,3015VA

NA NA NA NA NA NA

2 T1CORE2

SGT132kVSIDE

50/51NS+5CBF1

(REC670)+50CBF2(REB

650)

REF615+REC670+REB650

3000 3000 1 X 1000 1000 25 25 7 7

3 T1CORE3 87C2+95C2 REB650 3000 3000 1 X 1000 1000 25 25 7 7

4 T1CORE4 87C1+95C1 REC670 3000 3000 1 X 1000 1000 25 25 7 7

5 T2CORE1 SPARE 3000 3000 1 X 1000 1000 25 25 7 7


RET670 4000 4000 1 X 800 800 25 25 6 6


RET670 4000 4000 1 X 800 800 25 25 6 6

1 BCT3 87C1+95C1 REC670 3000 3000 1 X 1000 1000 25 25 7 7

2 BCT4 87C2+95C2 REB650 3000 3000 1 X 1000 1000 25 25 7 7

132kVBayNo=D05,

=D06,=D14(132kVSIDESGTBAYS)

SGTBushingCTs




AdoptedTap(Amp)

CTSecondary


CTKneePoint

VoltageAtAdopted



CTResistance(Ohms)


Tap(Ohms)

1 T9CORE1 DPDM(LCC)+BCU(LCC)

DPDM(LCC)+BCU(LCC)

40002000 2000 1 0.2FS5,3015VA

NA NA NA NA NA NA


RET670 4000 4000 1 X 800 NA 25 NA 6 NA

6T10CORE1

87B(DISCZONE)

REC670 4000 4000 1 X 800 NA 25 NA 6 NA

7T10CORE2

50/51+50N/51N+50BF1+50BF

2

REF615+REF615

4000 4000 1 X 800 NA 25 NA 6 NA

132kVBayNo=D130,=D230,

=D120,=D220(132kVBUSSECTION&

BUSCOUPLERBAYS)



System Data

SystemFaultLevel,Ikmax1 40 kAmp

VoltageLevel,Vp 132 kV

SystemX/RRatio 50

Copper Prperties

ResitivityofCopperat20oC, 17.2 nm

TemperatureCoefficientofCopper, 0.0039

FirstTemperature 20 oC

SecondTemperature 75 oC

ChangeinTemperature,t 55 oC

CT Secondary Cct Cable Data For 4mm2 Size

AreaofCrossSection,A 4 mm2

LengthoftheConductor 1000 mm

Resistanceper1000mmat20oC,R20=xl/A 0.0043

FirstTeperature,T1 20 OC

SecondTeperature,T2 75 OC

DifferenceinTemperaturwe,t=T2T1 55 OC

Resistanceat75oC,R75=R20x(1+xt) 0.00522235

SYSTEMDATA CE267304 10/50


CT Secondary Cct Cable Data For 10mm2 Size

AreaofCrossSection,A 10 mm2

LengthoftheConductor 1000 mm

Resistanceper1000mmat20oC,R20=xl/A 0.00172

FirstTeperature,T1 20 OC

SecondTeperature,T2 75 OC

DifferenceinTemperaturwe,t=T2T1 55 OC

Resistanceat75oC,R75=R20x(1+xt) 0.00208894

SYSTEMDATA CE267304 11/50


1 CTData(GTBays,=D09,=D04,=D10)CTNo T5CORE3

FunctionMAIN1

PROTN(BOX1)+FR

RelayType RET670+HATHAWAY

CTPrimary(Amp) 300 AmpAdoptedTap(Amp) 300 AmpCTSecondary 1 AmpCTClass XCTKneePointVoltage 360 VoltsCTKneePointVoltageAtAdoptedTap 360 VoltsCTMagnetizingCurrent(mAmp) 50 mAmpCTMagnetizingCurrentAtSelectedTap 50 mAmpCTResistance(Ohms) 1 CTResistanceSelectedTap(Ohms) 1 CTKneePointVoltageCalculation

2 Lead Burden

87T1GT(RET670) CE267304 12/50

2 LeadBurdenCTCableRouteLength(OneWay) 200 metreCTCableSize 4 mm2

CTCableResistancepermetre RefferSystemData 0.00522235 TotalCTCableResistance(OneWay) =0.00522235x200 1.04447

3 RelayBurdenVABurdenofRET670CTInput 0.02 VAVABurdenofFRCTInput 0.05 VA(As

sumed

TotalVABurden =0.02+0.05 0.07RatedSecondaryCurrent,In 1 AmpRelayCTInputResistance=VA/In2 =0.07/1^2 0.07

4 CTStabilityCriterion

87T1GT(RET670) CE267304 12/50


Themaximumexternal(through)faultcurrentislimitedbythe%ZofthetransformerandgivenbyItf=MVA(TF)x1000x100/(SQRT(3)xkVx%Z)

132/13.8kVGTMVARating 60 MVAGridTransformer%Impedance,%Z 10 %GridTransformerHVSideVoltage,kV 132 kV

Itf=MVA(TF)x1000x100/(SQRT(3)xkVx%Z) =60x10^5/(SQRT(3)x132x10)

2624.32 Amp

Transformerratedcurrent,Itn=MVA(TF)x1000/(SQRT(3)xkV) =60x1000/(SQRT(3)x132) 262.432 AmpKneepointvoltageaspercriterionNo.1,Vk=30xIntx(Isn/Ipn)x[Rct+2xRlead+Rrelay]

=30x262.432x1/300x(1+2x1.04447+0.07) 82.901 Volts

KneepointvoltageaspercriterionNo.2,Vk=2xItfx(Isn/Ipn)x[Rct+2xRlead+Rrelay =2x2624.32x1/300x(1+2

1 04447 + 0 07)55.267

TherearaetwocriterionforestimatingtheminimumrequirementforCTKneePointVoltage

CriterionNo.1,Vk=30xIntx(Isn/Ipn)x[Rct+2xRlead+Rrelay],Where,Int=transformerratedcurrent,Ipn=CTPrimaryratedCurrent,&Isn=CTSecondaryratedcurrent

CriterionNo.2,Vk=2xItfx(Isn/Ipn)x[Rct+2xRlead+Rrelay],Where,Itf=transformerthroughfaultcurrent

87T1GT(RET670) CE267304 13/50

Vk x Itf x (Isn/ Ipn) x [ Rct x Rlead Rrelay]

x1.04447+0.07) 55. 67

Therequiredkneepoint=max(CriterionNo.1,CriterionNo.2) 82.901 VoltsCTActualKneePointVoltage 360 VoltsHencetheCTKneePointVoltageisOK

87T1GT(RET670) CE267304 13/50


1 CTData(GTBays,=D09,=D04,=D10)CTNo T5CORE2

FunctionMAIN2

PROTN(BOX2)

RelayType RET670CTPrimary(Amp) 300 AmpAdoptedTap(Amp) 300 AmpCTSecondary 1 AmpCTClass XCTKneePointVoltage 360 VoltsCTKneePointVoltageAtAdoptedTap 360 VoltsCTMagnetizingCurrent(mAmp) 50 mAmpCTMagnetizingCurrentAtSelectedTap 50 mAmpCTResistance(Ohms) 1 CTResistanceSelectedTap(Ohms) 1 CTKneePointVoltageCalculation

2 Lead Burden

87T2GT(RET670) CE267304 14/50

2 LeadBurdenCTCableRouteLength(OneWay) 200 metreCTCableSize 4 mm2

CTCableResistancepermetre RefferSystemData 0.00522235 TotalCTCableResistance(OneWay) =0.00522235x200 1.04447

3 RelayBurdenVABurdenofRET670CTInput 0.02 VAVABurdenofFRCTInput (NoFR) 0 VATotalVABurden =0.02+0 0.02RatedSecondaryCurrent,In 1 AmpRelayCTInputResistance=VA/In2 =0.02/1^2 0.02

4 CTStabilityCriterion

87T2GT(RET670) CE267304 14/50


Themaximumexternal(through)faultcurrentislimitedbythe%ZofthetransformerandgivenbyItf=MVA(TF)x1000x100/(SQRT(3)xkVx%Z)

132/13.8kVGTMVARating 60 MVAGridTransformer%Impedance,%Z 10 %GridTransformerHVSideVoltage,kV 132 kV

Itf=MVA(TF)x1000x100/(SQRT(3)xkVx%Z) =60x10^5/(SQRT(3)x132x10)

2624.32 Amp

Transformerratedcurrent,Itn=MVA(TF)x1000/(SQRT(3)xkV) =60x1000/(SQRT(3)x132) 262.432 AmpKneepointvoltageaspercriterionNo.1,Vk=30xIntx(Isn/Ipn)x[Rct+2xRlead+Rrelay]

=30x262.432x1/300x(1+2x1.04447+0.02) 81.589 Volts

KneepointvoltageaspercriterionNo.2,Vk=2xItfx(Isn/Ipn)x[Rct+2xRlead+Rrelay =2x2624.32x1/300x(1+2

1 04447 + 0 02)54.392

TherearaetwocriterionforestimatingtheminimumrequirementforCTKneePointVoltage

CriterionNo.1,Vk=30xIntx(Isn/Ipn)x[Rct+2xRlead+Rrelay],Where,Int=transformerratedcurrent,Ipn=CTPrimaryratedCurrent,&Isn=CTSecondaryratedcurrent

CriterionNo.2,Vk=2xItfx(Isn/Ipn)x[Rct+2xRlead+Rrelay],Where,Itf=transformerthroughfaultcurrent

87T2GT(RET670) CE267304 15/50

Vk x Itf x (Isn/ Ipn) x [ Rct x Rlead Rrelay]

x1.04447+0.02) 54.39

Therequiredkneepoint=max(CriterionNo.1,CriterionNo.2) 81.589 VoltsCTActualKneePointVoltage 360 VoltsHencetheCTKneePointVoltageisOK

87T2GT(RET670) CE267304 15/50


SGTBays,BayNo=D05,D06,D141 CTData

CTNo T1CORE4

Function87C1+95C

1

RelayType REC670CTPrimary(Amp) 3000 AmpAdoptedTap(Amp) 3000 AmpCTSecondary 1 AmpCTClass XCTKneePointVoltage 1000 VoltsCTKneePointVoltageAtAdoptedTap 1000 VoltsCTMagnetizingCurrent(mAmp) 25 mAmpCTMagnetizingCurrentAtSelectedTap 25 mAmpCTResistance(Ohms) 7 CTResistanceSelectedTap(Ohms) 7

2 CTKneePointVoltageCalculationCTCableRouteLength(OneWay) 400 metreCTCableSize 4 mm2

87C1+95C1SGT(REC670) CE267304 16/50

CTCableResistancepermetre RefferCTData 0.005222 TotalCTCableResistance(OneWay) =0.00522235x400 2.08894 MaximumSecondaryThroughFaultCurrent,Ifs=Issc/Ipn =40x1000/3000 13.333 AmpRequiredVoltageSetting,Vsmin=Ifsx[Rct+2xRlead] =13.333x(7+2x2.08894) 149.035 VoltsAdoptedVoltageSetting=1.2xVsmin =1.2x149.035 178.842 VoltsTheCTisOKsinceVk>1.2xVs

3VoltageSettingOfREC670+SeriesResistanceCombination

REC670CurrentSettingRange=0.01xInto25xIn 0.01to25 AmpSelectedCurrentSetting,Is=0.1x1000mAmp 100 mAmpToprovidegreaterstabilityagainstthroughfaults,theVoltagesettingof179isproposedHenceRelaySettingVoltage,Vs 179 VoltsTherequiredseriesresistorvalue,Rs=Vs/Is =179x1000/100 1790

4 ShuntResistorCalculationTocalculatetheshuntresistorvalue,wehavetocalculatetheminimumoperatingcurrentofthedifferentialschemeIop=Ir+Im+Isupvn+Imet

87C1+95C1SGT(REC670) CE267304 16/50


WhereIr=REC670operatingcurrent 100 mAmpIm=MagnetizingCurrentForCTsatSettingVoltage 4.48 mAmpCTSupervisionRelayCurrent CTSUPVNBuiltInFunction 0 mAmpImet,MetrosilCurrent=0atsettingvoltage 0 mAmpIop=Ir+Im+Isupvn+Imet =100+4.48+0+0 104.48 mAmpAsperSECCOApractice,theprimaryoperatingcurrentshouldnotbelessthat1.2timestheCTprimary=1.2x3000

=1.2x3000 3600 Amp

RequiredSecondaryOperatingCurrent,Iops =3600x10001/3000 1200 mAmpCurrentThroughTheShuntResistor,Ish=IopsIop =1200104.48 1095.52 mAmpRequiredValueofShuntResistor,Rsh=Vs/Ish =179x1000/1095.52 163.39 OhmsRequiredWattageofShuntResistor=Vs2/Rsh =179^2/163.39 196.1 Watts

5 CTSupervisionSettings

Minimumload=0.25xCTPrimary =0.25x3000 750 AmpSecondarycurrentduringminimumload,Ismin =750x1/3000 0.25 Amp

CTSupervisionElementshouldoperatewhenofoftheCTsisopenandthereisminimumloadonthatfeeder.Wecantaketheminimumloadtobe40%oftheratedCTPrimary

TheresultantresistanceoftheCTcircuitduringCTopenconditionswillbeequaltotheparallelcombinationoftheshuntresistance,relayseriesresistance,andtheCTmagnetizingimpedance

87C1+95C1SGT(REC670) CE267304 17/50

Relayseriesresistance,Rs Calculatedabove 1790 RelayShuntresistance,Rsh Calculatedabove 163.39 CTmagnetizingimedance,Xm=Vk/Im =1000x1000/7 142857.1 Theresultantresistance1/R=1/Rs+1/Rsh+1/Xm

R=RsxRshxXm/[RsxXm+RsxXm+RsxRsh]=1790x163.39x142857.142857143/(1790x163.39+1790x142857.142857143+163.39x142857.142857143)

149.567

VoltagedevelopedacrosstheCTsupervisionrelay=IsminxR =0.25x149.567 37.39175 VoltsThecurrentthroughtherelayandseriesresistancecct,Ir=Vr/Rs =37.39175/1790 0.021 AmpHencetheCTsupvnelementpickupVoltage 38 Volts

87C1+95C1SGT(REC670) CE267304 17/50


SGTBays,BayNo=D05,D06,D141 CTData

CTNo T1CORE3

Function87C2+95C

2

RelayType REB650CTPrimary(Amp) 3000 AmpAdoptedTap(Amp) 3000 AmpCTSecondary 1 AmpCTClass XCTKneePointVoltage 1000 VoltsCTKneePointVoltageAtAdoptedTap 1000 VoltsCTMagnetizingCurrent(mAmp) 25 mAmpCTMagnetizingCurrentAtSelectedTap 25 mAmpCTResistance(Ohms) 7 CTResistanceSelectedTap(Ohms) 7


87C2+95C2SGT(REB650) CE180973 18/50


3VoltageSettingOfREB650+SeriesResistanceCombination

REB650CurrentSettingRange 0.021 AmpSelectedCurrentSetting,Is=0.1x1000mAmp 100 mAmpToprovidegreaterstabilityagainstthroughfaults,theVoltagesettingof179isproposedHenceRelaySettingVoltage,Vs 179 VoltsTherequiredseriesresistorvalue,Rs=Vs/Is =179x1000/100 1790

4 ShuntResistorCalculationTocalculatetheshuntresistorvalue,wehavetocalculatetheminimumoperatingcurrentofthedifferentialschemeIop=Ir+Im+Isupvn+Imet

87C2+95C2SGT(REB650) CE180973 18/50


WhereIr=REB650operatingcurrent 100 mAmpIm=MagnetizingCurrentForCTsatSettingVoltage 4.48 mAmpCTSupervisionRelayCurrent CTSUPVNBuiltInFunction 0 mAmpImet,MetrosilCurrent=0atsettingvoltage 0 mAmpIop=Ir+Im+Isupvn+Imet =100+4.48+0+0 104.48 mAmpAsperSECCOApractice,theprimaryoperatingcurrentshouldnotbelessthat1.2timestheCTprimary=1.2x3000

=1.2x3000 3600 Amp

RequiredSecondaryOperatingCurrent,Iops =3600x10001/3000 1200 mAmpCurrentThroughTheShuntResistor,Ish=IopsIop =1200104.48 1095.52 mAmp

RequiredValueofShuntResistor,Rsh=Vs/Ish =179x1000/1095.52 163.39 Ohms

RequiredWattageofShuntResistor=Vs2/Rsh =179^2/163.39 196.1 Watts5 CTSupervisionSettings




87C2+95C2SGT(REB650) CE180973 19/50



149.567

VoltagedevelopedacrosstheCTsupervisionrelay=IsminxR =0.25x149.567 37.39175 VoltsThecurrentthroughtherelayandseriesresistancecct,Ir=Vr/Rs =37.39175/1790 0.021 Amp

HencetheCTsupvnelementpickupVoltage 38 Volts


87C2+95C2SGT(REB650) CE180973 19/50


BAYNo=D05,=D06,=D141 CTDETAILS

CTNo T1CORE2

Function

SGT132kVSIDE50/51NS+5CBF1(REC670)+50CBF2(REB650)

Meter/RelayType REF615+REC670+REB650

CTPrimary(Amp) 3000 AmpAdoptedTap(Amp) 3000 AmpCTSecondary 1 AmpCTClass XCTKneePointVoltage 1000 VoltsCTKneePointVoltageAtAdoptedTap 1000 VoltsCTMagnetizingCurrent(mAmp) 25 mACTMagnetizingCurrentAtSelectedTap 25 mACTResistance(Ohms) 7 CTResistanceSelectedTap(Ohms) 7

2 METERBURDENDETAILS50/51NSBurden 0.1 VA(Assumed

)

SGT132kVOCEF CE267304 20/50

50CBF1Burden 0.1 VA(Assumed)

50CBF2Burden 0.0001 VA

AnyOtherDeviceBurden (Nootherdevice) 0 VA

TotalBurden =0.1+0.1+0.0001+0 0.2001 VA

TotalBurdenResistance,Rb=VA/In2 =0.2001/1^2 0.2001 3 CTLEADBURDEN

LeadLength(OneWay),L 200 metreLeadSize,A 4 mm2

LeadResistancepermetre,rl RefferSystemData 0.00522235 /metreTotalLeadResistance,RLEAD=rlxL =0.00522235x200 1.04447

4 CLASSXCONVERSIONTPPCLASS

Sn=[1.3xVk/(FnxIn)Rct]xIn^2

The followingformulaisusedtoconvertclassXCTtoequivalentPclassCTVk=FnxInx[Rct+Sn/In^2]/1.3ORSn=[1.3xVk/(FnxIn) Rct]xIn^2



Fn 20

Sn=[1.3xVk/(FnxIn)Rct]/In^2 =1.3x1000/(20x1)7)x1^2)

58 VA

4CRITERIONFORMETERINGCLASSCTADEQUACY

Fa=Fnx[Sin+Sn]/[Sin+Sa]Fn=CTAccuracyLimitingFactoratRatedBurden

20

Sn=CTRatedVABurden 58 VASin=In2xRct =1^2x7 7 VASa=In2x[Rleadx2+Rrelay] =1^2x(2x1.04447+0.2001) 2.28904 VA

Fa=Fnx[Sin+Sn]/[Sin+Sa] =20x(7+58)/(7+2.28904) 139.95

TheCTisOKsinceFa>Fn




132kVReactor(BayNo=D21,=D26)1 CTData

CTNo T7CORE3

Function 87C+95CRelayType REC670

CTPrimary(Amp) 1200600400200 Amp

AdoptedTap(Amp) 1200 AmpCTSecondary 1 AmpCTClass X

CTKneePointVoltage2400

1200800400

Volts

CTKneePointVoltageAtAdoptedTap 2400 VoltsCTMagnetizingCurrent(mAmp) 8.3316.7

2550 mAmpCTMagnetizingCurrentAtSelectedTap 8.33 mAmpCTResistance(Ohms) 6321 CTResistanceSelectedTap(Ohms) 6

2 CTKneePointVoltageCalculationCTCableRouteLength(OneWay) 400 metreCT Cable Size 4 2

87C+95C(REC670)132kVREACTOR CE267304 22/50

CTCableSize 4 mm2




4 ShuntResistorCalculationTocalculatetheshuntresistorvalue,wehavetocalculatetheminimumoperatingcurrentofthedifferentialscheme



Iop=Ir+Im+Isupvn+ImetWhereIr=REC670operatingcurrent 100 mAmpIm=MagnetizingCurrentForCTsatSettingVoltage 1.42 mAmpCTSupervisionRelayCurrent CTSUPVNBuiltInFunction 0 mAmpImet,MetrosilCurrent=0atsettingvoltage 0 mAmpIop=Ir+Im+Isupvn+Imet =100+1.42+0+0 101.42 mAmpAsperSECCOApractice,theprimaryoperatingcurrentshouldnotbelessthat1.2timestheCTprimary=1.2x3000

=1.2x1200 1440 Amp







Relayseriesresistance,Rs Calculatedabove 4080 RelayShuntresistance,Rsh Calculatedabove 371.39 CTmagnetizingimedance,Xm=Vk/Im =1000x2400/6 400000 Theresultantresistance1/R=1/Rs+1/Rsh+1/Xm

R=RsxRshxXm/[RsxXm+RsxXm+RsxRsh]=4080x371.39x400000/(4080x371.39+4080x400000+371.39x400000)

340.115





1 CTData(ReactorBay=D21&=D26)CTNo LC11 &NC21Function 87R+95R

RelayType REB650

CTPrimary(Amp) 600400200

Amp

AdoptedTap(Amp) 200 AmpCTSecondary 1 AmpCTClass XCTKneePointVoltage NOT

AVILABLEVolts

CTKneePointVoltageAtAdoptedTap 400 VoltsCTMagnetizingCurrent(mAmp) NOT

AVILABLEmAmP

CTMagnetizingCurrentAtSelectedTap 50 mAmPCTResistance(Ohms) NOT

AVILABLE

CTResistanceSelectedTap(Ohms) 1 2 CTKneePointVoltageCalculation

CTCableRouteLength(OneWay) 400 metreCTCableSize 4 mm2

CTCableResistancepermetre 0.00522235 TotalCTCableResistance(OneWay) =0.00522235x400 2.08894

3 ReactorThroughFaultCurrentCalculationReactorMVARrating 40 MVARReactorVoltageRating,kV 132 kVReactorThroughCurrent,Itr=1000xMVA/[SQRT(3)xkV] =40x1000/[SQRT(3)x132] 174.955 AmpReactorCTSecondaryThroughCurrent,Itrs=Itr/CTPrimary =174.955/200 0.874775 AmpRequiredVoltageSetting,Vsmin=Itrsx[Rct+2xRlead] =0.874775x[1+2x2.08894] 4.53 VoltsAdoptedVoltageSetting=1.2xVsmin =1.2x4.53 5.436 VoltsTheCTisOKsinceVk>1.2xVs

3VoltageSettingOfREB650+SeriesResistanceCombination

87R+95R(REB650)REACTOR CE267304 24/50


REB650CurrentSettingRange 0.021 AmpSelectedCurrentSetting,Is=0.03x1000mAmp

30 mAmp

Toprovidegreaterstabilityagainstthroughfaults,theVoltagesettingof11isproposedHenceRelaySettingVoltage,Vs 11 VoltsTherequiredseriesresistorvalue,Rs=Vs/Is =11/30x1000 366.67

4 ShuntResistorCalculationTocalculatetheshuntresistorvalue,wehavetocalculatetheminimumoperatingcurrentofthedifferentialschemeIop=Ir+Im+Isupvn+ImetWhereIr=REB650operatingcurrent 30 mAmpIm=MagnetizingCurrentForCTsatSettingVoltage

1.38 mAmp

CTSupervisionRelay(BuiltIn)Current 0 mAmpImet,MetrosilCurrent=0atsettingvoltage 0 mAmpIop=Ir+Im+Isupvn+Imet =30+1.38+0+0 31.38 mAmpItisproposedthat,theprimaryoperatingcurrentshouldnotbelessthat0.1timestheCTprimary=0.1x200

=0.1x200 20 Amp

RequiredSecondaryOperatingCurrent,Iops =20x1000x/400 100 mAmpCurrentThroughTheShuntResistor,Ish=IopsIop =10031.38 68.62 mAmpRequiredValueofShuntResistor,Rsh=Vs/Ish

=11x1000x/68.62 160.3 OhmsRequiredWattageofShuntResistor=Vs2/Rsh

=11^2/160.3 0.75 Watts6 CTSupervisionSettings

CTSupervisionElementshouldoperatewhenofoftheCTsisopenandthereisminimumloadonthatfeeder.ForReactor,wetaketheminimumloadtobe100%oftheratedCTPrimary

Minimumload=ReactorRatedLoad 174.955 AmpSecondarycurrentduringminimumload,Ismin

=174.955/200 0.874775 Amp

87R+95R(REB650)REACTOR CE267304 25/50


TheresultantresistanceoftheCTcircuitduringCTopenconditionswillbeequaltotheparallelcombinationoftheshuntresistance,relayseriesresistance,andtheCTmagnetizingimpedanceRelayseriesresistance,Rs 366.67 RelayShuntresistance,Rsh 160.3 CTmagnetizingimedance,Xm=Vk/Im =400/50 8 Theresultantresistance1/R=1/Rs+1/Rsh+1/XmR=RsxRshxXm/[RsxXm+RsxXm+RsxRsh]

=366.67x160.3x8/(366.67x160.3+366.67x8+160.3x8)

7.465

VoltagedevelopedacrosstheCTsupervisionrelay=IsminxR =0.874775x7.465 6.53 VoltsThecurrentthroughtherelayandseriesresistancecct,Ir=Vr/Rs =6.53/366.67 0.018 Amp

HencetheCTsupvnelementpickupVoltage 7 Volts

87R+95R(REB650)REACTOR CE267304 26/50


1 CTDETAILSREACTOR(BayNo=D21,=D26)CTNo T7CORE2Function 50/51N+FRMeter/RelayType REF615+FRCTPrimary(Amp) 1200600400

200Amp

AdoptedTap(Amp) 200 AmpCTSecondary 1 AmpCTClass XCTKneePointVoltage 24001200800

400Volts

CTKneePointVoltageAtAdoptedTap 400 VoltsCTMagnetizingCurrent(mAmp) 8.3316.72550 mAmPCTMagnetizingCurrentAtSelectedTap 50 mAmPCTResistance(Ohms) 6321 CTResistanceSelectedTap(Ohms) 1

2 RELAYBURDENDETAILSConnectedBurdenReactorOC/EFRelayREF615Burden 0.02 VAFRCTInputBurden 0.02 VATotalDeviceBurden 0.04 VA

3 CTLEADBURDENLeadLength(OneWay),L 100 metreLeadSize,A 4 mm2

LeadResistancepermetre,rl 0.00522235 /metreTotalLeadResistance,RLEAD=rlxL 0.522235

4 CRITERIONFOROC/EFRELAYREF615TheOC/EF+50BFrelayREF615isconnectedtoclassXCT.ItsequivalentPclassCTparametersarecalculatedbytheformula,Sn=[1.3xVkFnxInxRct]xIn/Fn,Where

5051+50BF1(BUILTIN)REACTOR CE267304 27/50


Fn=CTAccuracyLimitingFactoratRatedBurden 20Sn=CTRatedVABurden==[1.3xVkFnxInxRct]xIn/Fn

25

TheCriterionforanyPclassCTusedforOC/EFprotection,ingeneralisgivenby,Fa=Fnx[Sin+Sn]/[Sin+Sa]

Sin=CTInternalBurden=In2xRct 1 VASa=CTConnectedBurden=In2x[Rleadx2+Rrelay] 1.08447 VA

ActualAccuracyLimitingFactor,Fa=Fnx[Sin+Sn]/[Sin+Sa] 249.46MaximumSecondaryShortCircuitCurrent,Issc=MaximumPrimary(40kAmp)/CTPrimary 200TheActualAccuracyLimitingFactorhastobecomparedwiththemaximumsecondaryshortcircuitcurrent,andFaisOKifFa>IHIGHSET

FaISOK

5051+50BF1(BUILTIN)REACTOR CE267304 28/50


1 CTDETAILS(ReactorBay=D21&=D26)CTNo NC22Function 51NR

RelayType REF615CTPrimary(Amp) 400 AmpAdoptedTap(Amp) 400 AmpCTSecondary 1 AmpCTClass 5P20,15VACTResistance(Assumed) 2

2 RELAYBURDENDETAILSConnectedBurdenReactor51NRRelayREF615Burden 0.02 VATotalDeviceBurden 0.02 VA


LeadResistancepermetre,rl 0.00522235 /metre

TotalLeadResistance,RLEAD=rlxL =200x0.00522235 1.04447 4 CRITERIONFOROC/EFRELAY7SJ64

TheCriterionforanyPclassCTusedforOCprotection,ingeneralisgivenby,Fa=Fnx[Sin+Sn]/Fn=CTAccuracyLimitingFactoratRatedBurden

20

Sin=CTInternalBurden=In2xRct =1^2x2 2 VASn=CTRatedBurden 15 VASa=CTConnectedBurden=In2x[Rleadx2+Rrelay] =1^2x(1.04447x2+0.02) 2.10894 VAActualAccuracyLimitingFactor,Fa=Fnx[Sin+Sn]/[Sin+Sa] =20x(2+15)/(2+2.10894) 82.746

51NR(REF615)REACTOR CE267304 29/50


MaximumNeutralCurrent=ReactorRatedCurrent 0.874775 Amp

TheActualAccuracyLimitingFactorhastobecomparedwiththemaximumsecondaryshortcircuitcurrent,andFaisOKifFa>Imax

FaISOK

51NR(REF615)REACTOR CE267304 30/50


1CTDETAILS(BUSSECTION=D120,=D220,BUSCOUPLER=D130,=D230)CTNo T10CORE2

Function50/51+50N/51N+50BF1+50BF2

Meter/RelayType REF615+REF615

TwoNoCTPrimary(Amp) 4000 AmpAdoptedTap(Amp) 4000 AmpCTSecondary 1 AmpCTClass XCTKneePointVoltage 800 VoltsCTKneePointVoltageAtAdoptedTap NA VoltsCTMagnetizingCurrent(mAmp) 25 mAmPCTMagnetizingCurrentAtSelectedTap NA mAmPCTResistance(Ohms) 6 CTResistanceSelectedTap(Ohms) NA

BSBC5051+50BF1+50CBF2 CE267304 31/50

2 RELAYBURDENDETAILSConnectedBurdenBusSectionOC+50BF1RelayREF615Burden 0.02 VABusSectionEF+50BF2RelayREF615Burden 0.02 VATotalDeviceBurden =0.02+0.02 0.04 VA



TotalLeadResistance,RLEAD=rlxL =0.00522235x200 1.04447 4 CRITERIONFOROC/EFRELAY7SJ64

TheOC+50BF1&EF+50BF2relaysREF615areconnectedtoclassXCT.ItsequivalentPclassCTparametersarecalculatedbytheformula,Sn=[1.3xVk FnxInxRct]xIn/Fn

BSBC5051+50BF1+50CBF2 CE267304 31/50


Fn=CTAccuracyLimitingFactoratRatedBurden 20Sn=CTRatedVABurden==[1.3xVkFnxInxRct]xIn/Fn

=(1.3x80020x1x6)x1/20 46

Sin=CTInternalBurden=In2xRct =1^2x6 6 VASa=CTConnectedBurden=In2x[Rleadx2+Rrelay]

=1^2x(1.04447x2+0.04)

2.12894 VA

ActualAccuracyLimitingFactorFa=Fnx[Sin+Sn]/[Sin+Sa]

=20x(6+46)/(6+2.12894)

127.94

MaximumSecondaryShortCircuitCurrent,Issc=MaximumPrimary(40kAmp)/CTPrimary =40x1000/4000 10

TheActualAccuracyLimitingFactorhastobecomparedwiththemaximumsecondaryshortcircuitcurrent,andFaisOKifFa>IHIGHSET

FaISOK

TheCriterionforanyPclassCTusedforOC/EFprotection,ingeneralisgivenby,Fa=Fnx[Sin+Sn]/[Sin+Sa]

BSBC5051+50BF1+50CBF2 CE267304 32/50BSBC5051+50BF1+50CBF2 CE267304 32/50


132kVBusbarDiscriminativeZones1 CTData

CTNo T2CORE2

Function87B(DISCZONE)

RelayType RET670CTPrimary(Amp) 4000 AmpAdoptedTap(Amp) 4000 AmpCTSecondary 1 AmpCTClass XCTKneePointVoltage 800 VoltsCTKneePointVoltageAtAdoptedTap 800 VoltsCTMagnetizingCurrent(mAmp) 25 mAmpCTMagnetizingCurrentAtSelectedTap 25 mAmpCTResistance(Ohms) 6 CTResistanceSelectedTap(Ohms) 6

2 CT Knee Point Voltage Calculation

Note:ThisCTdataisrelatedtoSGTbays132kVsideCTs. NotethatsamedataisapplicabletobusbarprotectionCTsofallbays

87B+95BDISC(REC670) CE267304 33/50


CTCableResistancepermetre RefferCTData 0.005222 TotalCTCableResistance(OneWay) =0.00522235x400 2.08894 MaximumSecondaryThroughFaultCurrent,Ifs=Issc/Ipn =40x1000/4000 10 AmpRequiredVoltageSetting,Vsmin=Ifsx[Rct+2xRlead] =10x(6+2x2.08894) 101.779 VoltsAdoptedVoltageSetting=1.2xVsmin =1.2x101.779 122.135 VoltsTheCTisOKsinceVk>1.2xVs



4 ShuntResistorCalculation

87B+95BDISC(REC670) CE267304 33/50


Tocalculatetheshuntresistorvalue,wehavetocalculatetheminimumoperatingcurrentofthedifferentialschemeIop=Ir+Im+Isupvn+ImetWhereIr=REC670operatingcurrent 100 mAmpIm=MagnetizingCurrentForCTsatSettingVoltage 3.84 mAmpCTSupervisionRelayCurrent CTSUPVNBuiltInFunction 0 mAmpImet,MetrosilCurrent=0atsettingvoltage 0 mAmpIop=Ir+Im+Isupvn+Imet =100+3.84+0+0 103.84 mAmpAsperSECCOApractice,theprimaryoperatingcurrentshouldnotbelessthat1.2timestheCTprimary=1.2x3000

=1.2x4000 4800 Amp




CTSupervisionElementshouldoperatewhenofoftheCTsisopenandthereisminimumloadonthatfeeder.Wecantake

87B+95BDISC(REC670) CE267304 34/50

Secondarycurrentduringminimumload,Ismin =1000x1/4000 0.25 Amp



102.75


TheresultantresistanceoftheCTcircuitduringCTopenconditionswillbeequaltotheparallelcombinationoftheshuntresistance,relayseriesresistance,andtheCT

87B+95BDISC(REC670) CE267304 34/50


132kVBusbarCheckZone1 CTData

CTNo T2CORE3

Function87B(CHKZONE)

RelayType RET670CTPrimary(Amp) 4000 AmpAdoptedTap(Amp) 4000 AmpCTSecondary 1 AmpCTClass XCTKneePointVoltage 800 VoltsCTKneePointVoltageAtAdoptedTap 800 VoltsCTMagnetizingCurrent(mAmp) 25 mAmpCTMagnetizingCurrentAtSelectedTap 25 mAmpCTResistance(Ohms) 6 CTResistanceSelectedTap(Ohms) 6

2 CTKneePointVoltageCalculationCT Cable Route Length ( One Way ) 400 metre

Note:ThisCTdataisrelatedtoSGTbays132kVsideCTs. NotethatsamedataisapplicabletobusbarprotectionCTsofallbays

87B+95BCHK(REC670) CE267304 35/50

CTCableRouteLength(OneWay) 400 metreCTCableSize 4 mm2

CTCableResistancepermetre RefferCTData 0.005222 TotalCTCableResistance(OneWay) =0.00522235x400 2.08894 MaximumSecondaryThroughFaultCurrent,Ifs=Issc/Ipn =40x1000/4000 10 AmpRequiredVoltageSetting,Vsmin=Ifsx[Rct+2xRlead] =10x(6+2x2.08894) 101.779 VoltsAdoptedVoltageSetting=1.2xVsmin =1.2x101.779 122.135 VoltsTheCTisOKsinceVk>1.2xVs



4 ShuntResistorCalculation

87B+95BCHK(REC670) CE267304 35/50


Tocalculatetheshuntresistorvalue,wehavetocalculatetheminimumoperatingcurrentofthedifferentialschemeIop=Ir+Im+Isupvn+ImetWhereIr=REC670operatingcurrent 100 mAmpIm=MagnetizingCurrentForCTsatSettingVoltage 3.84 mAmpCTSupervisionRelayCurrent CTSUPVNBuiltInFunction 0 mAmpImet,MetrosilCurrent=0atsettingvoltage 0 mAmpIop=Ir+Im+Isupvn+Imet =100+3.84+0+0 103.84 mAmpAsperSECCOApractice,theprimaryoperatingcurrentshouldnotbelessthat1.2timestheCTprimary=1.2x3000

=1.2x4000 4800 Amp




CTSupervisionElementshouldoperatewhenofoftheCTsisopenandthereisminimumloadonthatfeeder.Wecantake

87B+95BCHK(REC670) CE267304 36/50

Secondarycurrentduringminimumload,Ismin =1000x1/4000 0.25 Amp



102.75


TheresultantresistanceoftheCTcircuitduringCTopenconditionswillbeequaltotheparallelcombinationoftheshuntresistance,relayseriesresistance,andtheCT

87B+95BCHK(REC670) CE267304 36/50


BAYNo=D05,=D06,=D141 CTDETAILS

CTNo T1CORE1

FunctionDPDM(LCC)+BCU(LCC)+EM+DSM

MeterTypeDPDM(LCC)+BCU(LCC)+ALPHAA3+DSM

CTPrimary(Amp) 30001500 AmpAdoptedTap(Amp) 3000 AmpCTSecondary 1 AmpCTClass 0.2FS5,30

15VA

CTResistance,Rct(Assumed) 7.5 (Assumed)2 METERBURDENDETAILS

DPDM(LCC)Burden 0.1 VA(Assumed)BayControlUnitBurden 0.1 VA(Assumed)EnergyMeterAlphaA3Burden 0.0001 VADSMBurden 0.1 VA(Assumed)

Total Burden 0 1 + 0 1 + 0 0001 + 0 1 0 3001 VA

SGT132kVMETERING CE267304 37/50

TotalBurden =0.1+0.1+0.0001+0.1 0.3001 VA

TotalBurdenResistance,Rb=VA/In2 =0.3001/1^2 0.3001 3 CTLEADBURDEN

LeadLength(OneWay),L 200 metreLeadSize,A 4 mm2

LeadResistancepermetre,rl RefferSystemData 0.00522235 /metreTotalLeadResistance,RLEAD=rlxL =0.00522235x200 1.04447

4CRITERIONFORMETERINGCLASSCTADEQUACY

Fa=Fnx[Sin+Sn]/[Sin+Sa]Fn=CTAccuracyLimitingFactoratRatedBurden

5

Sn=CTRatedVABurden 30 VASin=In2xRct =1^2x7.5 7.5 VASa=In2x[Rleadx2+Rrelay] =1^2x(2x1.04447+0.3001) 2.38904 VACTAccuracyLimitingFactoratRatedBurden,Fn 5

Fa=Fnx[Sin+Sn]/[Sin+Sa] =5x(7.5+30)/(7.5+2.38904) 18.96

SGT132kVMETERING CE267304 37/50


MaximumSecondaryShortCircuitCurrent,Issc=MaximumPrimary(40kAmp)/CTPrimary

=40x1000x1/3000 13.333 Amp

Maximumanticipatedcurrentinthemeter,ImMAX 13.333 Amp

5MaximumShortdurationwithstandCurrents

DPDM(LCC) 20BCU(LCC) 20EnergyMeter 40DSM 40

MinimumShortDurationCurrent 20Themeterwillbesafe,sinceImMAX


GRIDTRANSFORMERFEEDERS=D09,=D04,=D10

1 CTDETAILSCTNo T5CORE1

Function

IPCT+DM(LCC)+BCU(LCC)+DSM+AMR+PQM

RelayTypeDM(LCC)+BCU(LCC)+DSM+AMR+PQM

CTPrimary(Amp) 300 AmpAdoptedTap(Amp) 300 AmpCTSecondary 1 AmpCTClass 5P20,30VACTKneePointVoltage NA VoltsCTKneePointVoltageAtAdoptedTap NA VoltsCTMagnetizingCurrent(mAmp) NA mAmpCT M ti i C t At S l t d T NA A

METERINGGTFEEDERS CE267304 39/50

CTMagnetizingCurrentAtSelectedTap NA mAmpCTResistance(Ohms) NA CTResistanceSelectedTap(Ohms) NA

2 DEVICEBURDENDETAILSBayControlUnit7SMD664Burden 0.05 VA

LCCDigitalMeterBurden 0.05VA(Assumed)

AlphaMeterCTBurdenperphase 0.0001 VA

DSMCTInputBurdenperphase 0.0001VA(Assumed)

ACCSBurden 0.05VA(Assumed)

TotalDeviceBurden =0.05+0.05+0.0001+0.0001+0.05 0.1502 VA

3 CTLEADBURDENLeadLength(OneWay),L 200 metre



LeadSize,A 4 mm2


TotalLeadResistance,RLEAD=rlxL =0.00522235x200 1.04447

IPCTBurden>LeadBurden+DeviceburdenLeadBurden=In2x2xRLEAD =1^2x1.04447 1.04447 VAIPCTBurden>LeadBurden+Deviceburden =0.1502+1.04447 1.19467 VA

RecommendedBurdenforIPCT 10 VARatio 1:1

Class 0.2

TheavailableCTformeteringisclassX.ButmeterscannotbefedbyclassXCT, asageneralrule.ThereforeIPCTisrecommendedtobeusedinthestartofthemeteringcircuit.ThequestionisnowtocalculatethesuitableIPCTburden




1CTDETAILS(BAYNo=D19,=D17,=D15,=D13,=D11,=D07,=D03,=D01,=D02,=D08,=D12,=D16,D18,=D20,D22,=D24CTNo T3CORE1

FunctionEnergyMeter+DSMThroughIPCT

RelayType ALPHAA3+DSM+IPCT


Amp


14001050 VoltsCTKneePointVoltageAtAdoptedTap 1400 VoltsCTMagnetizingCurrent(mAmp) 12.516.725

33.3mAmp

CTMagnetizingCurrentAtSelectedTap 25 mAmpCTResistance(Ohms) 4321.5

METERINGSPAREOGFEEDERS CE267304 41/50

CTResistanceSelectedTap(Ohms) 2 2 DEVICEBURDENDETAILS

BayControlUnit7SMD664Burden 0.05 VALCCDigitalMeterBurden 0.05 VA

(AssumAlphaMeterCTBurdenperphase 0.0001 VADSMCTInputBurdenperphase 0.0001 VA

(Assum

TotalDeviceBurden =0.05+0.05+0.0001+0.0001

0.1002 VA








Class 0.5





1 CTDETAILS(BAYNo=D17,=D02)CTNo T13CORE3

FunctionIPCT+DM(LCC)+EnergyMeter+DSM


CTPrimary(Amp) 2000160012001000800 Amp


CTKneePointVoltage 35002800210017501400 Volts


25mAmp

CTMagnetizingCurrentAtSelectedTap 20 mAmpCTResistance(Ohms) 5432.5

METERINGCAPACITORFEEDERS CE267304 43/50

CTResistanceSelectedTap(Ohms) 3 2 DEVICEBURDENDETAILS

BayControlUnit7SMD664Burden 0.05 VALCCDigitalMeterBurden 0.05 VA


(Assum


0.1002 VA




METERINGCAPACITORFEEDERS CE267304 43/50




Class 0.5


METERINGCAPACITORFEEDERS CE267304 44/50METERINGCAPACITORFEEDERS CE267304 44/50


1 CTDETAILS(BAYNo=D22)CTNo T11CORE3

FunctionIPCT+DM(LCC)+EnergyMeter+DSM


CTPrimary(Amp)300025002000160012001000

Amp


CTKneePointVoltage420035002800224016801400

Volts


15.620.825 mAmpCTMagnetizingCurrentAtSelectedTap 25 mAmpCTResistance(Ohms) 653.22.42

METERINGSPARESVCBAY CE267304 45/50

CTResistance(Ohms) 6 5 3.2 2.4 2 CTResistanceSelectedTap(Ohms) 2

2 DEVICEBURDENDETAILSBayControlUnit7SMD664Burden 0.05 VALCCDigitalMeterBurden 0.05 VA


(Assum


0.1002 VA








Class 0.5





REACTORFEEDERS=D21,=D261 CTDETAILS

CTNo T7CORE1

Function


RelayTypeDPDM(LCC)+BCU(LCC)+FR+IPCT+ENERGYMETER+DSM


Amp


400Volts

CTKneePointVoltageAtAdoptedTap 400 VoltsCTMagnetizingCurrent(mAmp) 8.3316.72550 mAmpCTMagnetizingCurrentAtSelectedTap 50 mAmp

METERINGREACTORFEEDERS CE267304 47/50

g g p p

CTResistance(Ohms) 6321 CTResistanceSelectedTap(Ohms) 1

2 DEVICEBURDENDETAILSBayControlUnit7SMD664Burden 0.05 VALCCDigitalMeterBurden 0.05 VA


(Assum


0.1002 VA




METERINGREACTORFEEDERS CE267304 47/50




Class 0.5


METERINGREACTORFEEDERS CE267304 48/50METERINGREACTORFEEDERS CE267304 48/50


1 CTDETAILSCTNo T9CORE1Function

DPDM(LCC)+BCU(LCC)

MeterType DPDM(LCC)+BCU(LCC)

CTPrimary(Amp) 40002000 AmpAdoptedTap(Amp) 2000 AmpCTSecondary 1 AmpCTClass 0.2FS5,3015VA

CTResistance,Rct(Assumed) 3.5(Assumed)

2 METERBURDENDETAILSConnectedBurdenistheEnergyMeterAlphaA3RAQAlphaMeterCTResistanceperphase 0.1 milli

OhmMeterBurdenatCTSecondaryRatedCurrent=In2xRmeter

0.0001 VA



TotalLeadResistance,RLEAD=rlxL =0.00522235x200 1.04447 4 CRITERIONFORMETERINGCLASSCTADEQUACY

TheCriterionforanyPclassCTusedforOC/EFprotection,ingeneralisgivenbyFa=Fnx[Sin+Sn]/[Sin+Sa]Fn=CTAccuracyLimitingFactoratRatedBurden 5Sn=CTRatedVABurden 15 VASin=CTInternalBurden=In2xRct =1^2x3.5 3.5 VASa=CTConnectedBurden=In2x[Rleadx2+Rrelay]

=1^2x(1.04447x2+0.0001) 2.08904 VA

CTAccuracyLimitingFactoratRatedBurden,Fn 5ActualAccuracyLimitingFactorFa=Fnx[Sin+Sn]/[Sin+Sa]

=5x(3.5+15)/(3.5+2.08904) 16.55

132kVBSBCMETERING CE267304 49/50


MaximumSecondaryShortCircuitCurrentIssc=MaximumPrimary(40kAmp)/CTPrimary =40x1000/2000 20

TheActualAccuracyLimitingFactorhastobecomparedwiththemaximumsecondaryshortcircuitcurrent,andFaisOKifFa

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