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1)1)1)

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2 2

2 2

1 1 3 3

1 2 1 32 3

1 32 1 32

9090

I245135

I245135

0180V1V2

0180V1

225 315

I1I1

270270

C Phase Symmetrical Component View of an A to B Phase FaultC Phase Symmetrical Component View of an A to B Phase Fault

9090

45135 45135

V0 V1V2

0180 V0 V1V2

225 315225 315

I0I1 I0I1I2

270

I2270

9090

45135 45135

I2I2

I0I0

V10180 V0

V1V2 V0V2

225 315225 315I1I1

270

IA IB IC IRIA IB IC IR

100

0

100

0

-100-100

100100

0

-100-100

100100

0

-100

0

-100

200200

-0-0

-200-200

1 2 3 4 5 6 7 8 9 10 111 2 3 4 5 6 7 8 9 10 11Cycles

90

45135 45135

V2

I1

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0180 I0

I1I2 0180 I0 I2 V1V1

225 315225 315

270270

Fault incident on voltage Fault incident on voltagezero point results inzero point results inAsymmetrical current waveAsymmetrical current wave

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Dead time -1 secDead time -1 sec

Dead time -1 secDead time -1 sec

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In inductive circuits the current normally lags the voltage by 90, and magnetic flux isIn inductive circuits the current normally lags the voltage by 90, and magnetic flux isnormally in phase with the inductive magnetizing current that has created it.normally in phase with the inductive magnetizing current that has created it.Therefore, at the transformer energization instant the required magnetic flux shouldTherefore, at the transformer energization instant the required magnetic flux shouldbe at 90, to correspond to the high-side zero-voltage point. But the transformerbe at 90, to correspond to the high-side zero-voltage point. But the transformermagnetic circuit has no flux, and as a result the flux must start at the zero point andmagnetic circuit has no flux, and as a result the flux must start at the zero point andmagnetic circuit has no flux, and as a result the flux must start at the zero point andovershoot to twice the maximum value during the first voltage cycle. This will causeovershoot to twice the maximum value during the first voltage cycle. This will causecore saturation, forcing the generation of a sharp unidirectional peakingcore saturation, forcing the generation of a sharp unidirectional peakingnonsinusoidal magnetizing current waveform that may persist for several seconds.nonsinusoidal magnetizing current waveform that may persist for several seconds.

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Microsoft OfficeMicrosoft OfficeWord 97 - 2003 DocumentWord 97 - 2003 Document

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VA VB VC IA IB IC

25

VA VB VC IA IB IC

025

-250

-25

250

25

-250

-25

250

25

-25

2500

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2500

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-2500

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2500

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1 2 3 4 5 6 7 8 9 10 111 2 3 4 5 6 7 8 9 10 11Cycles

IA IB IC IRIA IB IC IR

10000

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IA IB IC

10000

IA IB IC

10000

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-10000-10000

10000

00

-10000-10000

1 2 3 4 5 6 7 8 9 10 111 2 3 4 5 6 7 8 9 10 11CyclesCycles

IA IB IC IR5000

IA IB IC IR5000

00

-500050005000

00

-5000-500050005000

00

-5000-500025002500

00

-2500-2500

1 2 3 4 5 6 7 8 9 10 111 2 3 4 5 6 7 8 9 10 11CyclesCycles

IA IB IC IRIA IB IC IR

100

0

100

0

-100-100

100100

0

-100

0

-100

100

00

-100

200200

-0-0

-200-200

1 2 3 4 5 6 7 8 9 10 111 2 3 4 5 6 7 8 9 10 11CyclesCycles

286733TypewriterKARIKALAN.M

286733Typewriter

286733Typewriter