Power Quality and Simulation of VSC with Passive Harmonic Filters (By using Plecs program)

EE551 Spring 2020

PROJECT 3 Due Monday 31 August 2020

PART 1: Power Quality (10min presentation)

 Explain the difference between True power factor, Displacement power factor, and Distortion power factor.

 Draw waveforms of the four case belows and state what is the True pf in each case?:

1. Displacement pf =1 and Distortion pf =1

2. Displacement pf <1 and Distortion pf =1

3. Displacement pf =1 and Distortion pf <1

4. Displacement pf <1 and Distortion pf <1

 Write the equation defining THDv and THDi, explain them, and what do they tell in terms of power.

 Explain and summarize briefly the application of IEEE standard 519 for Harmonic Limits in Electric Power

Systems.

PART 2: Simulation of VSC with Passive Harmonic Filters (15 min presentation)

 Simulate a three-phase six-pulse Voltage Source Converter operating as rectifier and feeding a resistive dc

load of 1MW at 10kV dc.

 The rectifier is fed from the secondary side of a three-phase 1.5MW , 33/11kV , ∆-Y transformer with a short

circuit level of 200MVA and X/R ratio of 10.

 The transformer primary side is fed from an ideal 50Hz, 33kV, 3MVA generator through a feeder whose

impedance is 0.1 + j0.6Ω/phase.

1. Plot the transformer secondary side line currents and voltages for the three phases.

2. Plot the harmonic spectrum of the transformer secondary side line currents.

3. Find the THDi of the transformer secondary side line currents

4. Place a three-phase grounded Y harmonic series LC filter (between the transformer and the rectifier) to

filter out the 5 th

and 7th the harmonics generated by the converter. Assume filter capacitors provide a

reactive power of 0.4MVars/phase.

5. With the filter in place, plot the rectifier input line currents and the transformer secondary side line

currents for the three phases.

6. With the filter in place, plot the harmonic spectrum of the rectifier input line currents and the

transformer secondary side line currents.

7. With the filter in place, find the THDi of the rectifier input line currents and the transformer secondary

side line currents.

8. With the filter in place, plot the filter effectiveness ratio up to the 9 th

harmonic.

9. Assume the transformer short circuit level is reduced to 50MVA and using the same filter designed in

part 4, repeat parts (5 to 8) and comment on any shift observed in designed series resonant point.

Submit your work as a powerpoint presentation along with all

simulation files