EE1PEEE Refresher Class

Power Part 2

notes by T. Ernst

EE1 – Power Part 2 Notes Fall 2011, Page 1

Fall 2011, Page 2

EE1 – Power Part 2 Notes

• Power Transformers• Ideal• Real Models• Impedance Testing• Nameplate Data• 3-Phase Connections

Fall 2011, Page 3

EE1 – Power Part 2 Notes

2-Winding Ideal Transformer

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EE1 – Power Part 2 Notes

Ideal Transformer (more than 2 windings)

Fall 2011, Page 5

EE1 – Power Part 2 Notes

Models for Real Power Transformer (50 or 60 hz)

Fall 2011, Page 6

EE1 – Power Part 2 Notes

Excitation Characteristics and V/Hz Ratio

Fall 2011, Page 7

EE1 – Power Part 2 Notes

Transformer Impedance Testing•No-load losses [KW]

Fall 2011, Page 8

EE1 – Power Part 2 Notes

Transformer Impedance Testing•Series Impedance [pu]•Full-load losses [KW]

Fall 2011, Page 9

EE1 – Power Part 2 Notes

Transformer Impedance Testing

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EE1 – Power Part 2 Notes

Power Transformer Nameplates•Voltage Rating

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EE1 – Power Part 2 Notes

IEEE/ANSIC57.12.00

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EE1 – Power Part 2 Notes

IEEE/ANSIC57.12.00

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EE1 – Power Part 2 Notes

IEEE/ANSIC57.12.00

Fall 2011, Page 14

EE1 – Power Part 2 Notes

1-Phase Transformer•E/E1 GrdY (1 bushing plus grounding lug)

Fall 2011, Page 15

EE1 – Power Part 2 Notes

1-Phase Transformer•E/2E (4-bushing)•2E/E (3-bushing)

Fall 2011, Page 16

EE1 – Power Part 2 Notes

3-Phase Transformer•E (3-bushings)•E1Y (3-bushings)

Fall 2011, Page 17

EE1 – Power Part 2 Notes

3-Phase Transformer•E1Y/E (4-bushings)

•E/E1Y (3-bushing)

Fall 2011, Page 18

EE1 – Power Part 2 Notes

3-Phase Transformer• E1GrdY/E (4-bushings or 3-bushings plus grounding lug)

Fall 2011, Page 19

EE1 – Power Part 2 Notes

Power Transformer Nameplates• VA Rating

Fall 2011, Page 20

EE1 – Power Part 2 Notes

Fall 2011, Page 21

EE1 – Power Part 2 Notes

Power Transformer Nameplates• Impedance• Taps

Fall 2011, Page 22

EE1 – Power Part 2 Notes

Power Transformer Nameplates• Voltage Ratio• Turns Ratio

Fall 2011, Page 23

EE1 – Power Part 2 Notes

Power Transformer Nameplates• Current Ratio• Impedance Ratio

Fall 2011, Page 24

EE1 – Power Part 2 Notes

3-Phase Transformer Connections•Method to construct the phasor diagram from the wiring diagram (understand the phase shift through the transformer)•Method to construct the wiring diagram from the phasor diagram (match transformer connections to existing systems)

Fall 2011, Page 25

EE1 – Power Part 2 Notes

3-Phase Transformer Connections•Wye – Wye (subtractive polarity)

Fall 2011, Page 26

EE1 – Power Part 2 Notes

3-Phase Transformer Connections•Wye – Wye (additive polarity)

Fall 2011, Page 27

EE1 – Power Part 2 Notes

3-Phase Transformer Connections•Delta – Wye (ANSI Standard)

Fall 2011, Page 28

EE1 – Power Part 2 Notes

3-Phase Transformer Connections•Delta – Wye (non-standard)

Fall 2011, Page 29

EE1 – Power Part 2 Notes

3-Phase Transformer Connections•Delta – Wye (non-standard – alternate method)

Fall 2011, Page 30

EE1 – Power Part 2 Notes

3-Phase Transformer Connections•Zig-Zag Grounding

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EE1 – Power Part 2 Notes

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EE1 – Power Part 2 Notes

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EE1 – Power Part 2 Notes

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EE1 – Power Part 2 Notes

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EE1 – Power Part 2 Notes

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EE1 – Power Part 2 Notes

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EE1 – Power Part 2 Notes

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EE1 – Power Part 2 Notes

Fall 2011, Page 39

EE1 – Power Part 2 Notes