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FAULT LEVEL CALCULATION(PU Method)At 33 KV side of SPS Site.

Alternative-1Sr. No. Description Voltage Amps MVA Qty. Remarks

1 System Voltage220KV

2 Fault Level8.737KA

3 04 N0. of the transformer 2

5 Rating of each trans. 220/33KV 42/280A 16 MVA

69.98% cosidering 90% i.e. 8.982%

7 220/33 Kv

178.13MVA

80.56

10

0.31

11Fault Level At 33 side

12 5.63KA

erna ve-Sr. No. Description Voltage Amps MVA Qty. Remarks

1 System Voltage220KV

2 Fault Level8.737KA 3329.1 MVA

3 04 N0. of the transformer 25 Rating of each trans. 220/33KV 42/280A 50 MVA

611.82% cosidering 90% i.e. 10.638%

7 220/33 Kv470MVA

3329.1MVA

PU Rectance=BaseMVAFualt MVAXs=1003329.1PU Reactance of Considering 100MVA

% Impedance.of eachtrafo.

PU Rectance=BaseMVAFualt MVAXs=100178.13Fault rating of each

transfo.0.468/3.11KA

PU Reactance of Each Trafo.

Considering 100MVABase

PU Rectance=BaseMVAFualt MVA

Total PU Impedance( Xs+Xt)

Base(100)(Xs+St)=321.85

Total Fault Current At33KV Side

PU Rectance=BaseMVAFualt MVAXs=1003329.1PU Reactance of

System (Xs)Considering 100MVA

Base

% Impedance.of eachtrafo.

Fault rating of eachtransfo.

1.233/8.22KA

PU Rectance=BaseMVAFualt MVAXs=100470

PU Reactance of Considering 100MVA

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8 0.21

9 0.11

100.14

11Fault Level At 33 side

12 12.83KA

Alternative-3Sr. No. Description Voltage Amps MVA Qty. Remarks

1 System Voltage220KV

2 Fault Level8.737KA 3329.1 MVA

3 04 N0. of the transformer 25 Rating of each trans. 220/33KV 183.7/1224 70 MVA

612.52% cosidering 90% i.e. 11.268%

7 220/33 Kv621.22 MVA

8 0.17

9 0.08

100.11

11Fault Level At 33 side

1215.83KA

FAULT LEVEL CALCULATION(Simple Method)At 33 KV side of SPS Site.

Alternative-1Sr. No. Description Voltage Amps MVA Qty. Remarks

1System Voltage

220KV

2 Fault Level 8.737KA 3329.1MVA3 N0. of the transformer 24 Rating of each trans. 220/33KV 42/280A 16 MVA5 9.98% cosidering 90% i.e. 8.982%

Each Trafo.

Base

Total PU Reactanceof Trafo (Xt)

PU Rectance=BaseMVAFualt MVAXs=100(2x470)Total PU Impedance

( Xs+Xt)

Base(100)(Xs+St)=733.24 Fault Current=Base

MVATotal PUImpdance

Fault Current At 33KV Side

PU Rectance=BaseMVAFualt MVAXs=1003329.1PU Reactance of

System (Xs)Considering 100MVA

Base

% Impedance.of eachtrafo.

PU Rectance=BaseMVAFualt MVAXs=100621.22Fault rating of each

transfo.1.63/10.868KA

PU Reactance of Each Trafo.

Considering 100MVABase

PU Rectance=BaseMVAFualt MVAXs=100(2x621.22)Total PU Reactance

of Trafo (Xt)Total PU Impedance

( Xs+Xt)Base(100)(Xs+St)=

904.97 Fault Current=BaseMVATotal PU

ImpdanceFault Current At 33

KV Side

% Impedance.of each

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6 220/33 Kv178.13MVA

7356.26MVA

8 321.82MVA

9 5.63 KAAlternative-2

System Voltage1 220KV2 Fault Level 8.737KA 3329.1MVA3 N0. of the transformer 2

4 Rating of each trans. 220/33KV50 MVA

511.82% cosidering 90% i.e.10.638%

6 220/33 Kv 470 MVA

7940MVA

8 733.02MVA

9 12.82 KAAlternative-3

Sr. No. Description Voltage Amps MVA Qty. Remarks1

System Voltage220KV

2 Fault Level 8.737KA 3329.1MVA3 N0. of the transformer 24 Rating of each trans. 220/33KV 42/280A 70 MVA5

6 220/33 Kv621.22MVA

71242.45MVA

8904.77 MVA

9 15.83 KA

Fault Level CalculationAlternative-1

1 Voltage Level of the System 220KV

Fault rating of eachtransfo.

0.468/3.11KA

Total Fault Rating for both Trafo.

0.936/6.22KA

16x1008.982=178.13MVA

Total Impedanceduring Fault(Z)

0.844/5.63KA

Z=3329.1x356.263329.1+356.26=

321.82Total Fault Current At33 k v side

131.12/875Amps

% Impedance.of eachtrafo.

Fault rating of eachtransfo. 1.23/8.22KATotal Fault Rating for both Trafo.

2.44/16.22KA

Z=3329.1x9403329.1+940=733.02Total Impedance

during Fault(Z).896/5.98

KA

Total Fault Current At33Kv Side

% Impedance.of each 12.52% cosidering 90%Fault rating of eachtransfo.

1.63/10.86KA

70x1008.982=621.22MVA

Total Fault Rating for both Trafo.

3.26/21.75KA

Total Impedanceduring Fault

2.37/15.83KA

Z=3329.1x1242.453329.1+1242.45=

904.77Total Fault current At33KV Side

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2 Fault Level at220KV

332.1 MVA At Budipadar S/S

3 Fault current at 220KV

433

5

2

616MVA

7 9.98%8 8.98%9 100

10

110.56

1213 Xs+Xt= 0.3114 Fault Level at 33 KV15 fault Current at 33 kv side of System 5.63 KA

Alternative-II1 Voltage Level of the System 220KV

2 Fault Level at 220KV

3 Fault current at 220KV

433

5

2

650MVA

7 11.82%8 10.64%9 100

10 220KV Side

11 0.21

1213 Xs+Xt= 0.1414 Fault Level at 33 KV15 fault Current at 33 kv side of System 12.83 KA

KV side of System

KV side of System

8.737KA atBudipadar S/S

It is required to bedetermine the fault

KV side of thesystem.

No. of Transformer Installed in the S/S

( consideringfuture

extention)

Rating of EachTransformer 220/33 KV At

ONAF cooling

Reactance of Eachwith 10% negative

PU Reactance of thesystem UpTo

220KVSide

Xs=BaseMVA/FaultMVA=0.0300

PU Reactance of

Each Tranfo.at

100 MVA

basePU equivelentReactance Of Tranfo.

100 MVAbase

Xt=0.28069

Total PU equivelent,=

=

KV side of System

332.1 MVA AtBudipadar S/S

KV side of System

8.737 AtBudipadar S/S

It is required to bedetermine the fault

KV side of thesystem.

No. of Transformer Installed in the S/S

( consideringfuture

extention)

Rating of EachTransformer 220/33 KV At

ONAF cooling

Reactance of Eachwith 10% negative

Xs=BaseMVA/FaultPU Reactance of Each Tranfo.at

100 MVAbase

equ ve enReactance Of Tranfo. 100 MVAbase

Xt=0.10638

,=

=

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Alternative-III1 Voltage Level of the System 220KV

2 Fault Level at 220KV

3Fault current at

220KV

433

5

2

670MVA

7 12.52%8 11.27%9 100

10 220KV Side

11 0.16

1213 Xs+Xt= 0.1114 Fault Level at 33 KV15 fault Current at 33 kv side of System 15.83 KA

1 33KV2 Fault level At 33KV side of system 904.78MVA

3 33KV side of system 15.83KA4 6.6 KV of system

5 2 Nos.

6Rating Of Each trafo.

33KV/6.6KV 10MVA

7 8.40%

8 Assumed 7.56%

9 100MVA

10 33 KV Side 0.11

11 0.76

12 Xt=0.378

KV side of System

332.1 MVA AtBudipadar S/S

KV side of System

8.737 AtBudipadar S/S

It is required to bedetermine the fault

KV side of thesystem.

No. of Transformer Installed in the S/S

( consideringfuture

extention)

Rating of EachTransformer 220/33 KV At

ONAF cooling

Reactance of Eachwith 10% negative

Xs=BaseMVA/FaultPU Reactance of Each Tranfo.at

100 MVAbase

equ ve enReactance Of Tranfo. 100 MVAbase

Xt=0.08049

Side of System,=Base MVA/PU

Faultcurrent atIt required to bedetermine the faultlevel atNo. of Tranfo.Installed in S/S

Reactance of eachTrafo.With 10% Negativetolerance reactanceof each trafo.Let Cosider baseMVAPU Reactance of system upto

XS=Base MVA / FaultMVA

PU Reactance of each trafo at

100 MVABase

PU Equivelent 100 MVA

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Xs+Xt= 0.49

Fault level at

15 Fault current at 17.91 KA

reactance of trafo. Inparallel.At

base

Total PU EquivelentReactance

6.6 KV side of system=BaseMVA/PUEquivelent Reactance=

204.7MVA

6.6 KV side of system=BaseMVA/PUEquivelent Reactance=

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