ECE 5810, Spring 2006
C. McKeough
Unit I: Three-Phase Systems
Objectives
1.
Give the definitions and units for active (real) power P, reactive power Q, apparent power
|S|, complex power S and power factor PF.
2.
Apply the theorem of conservation of complex power to obtain P, Q, S and PF at a point
in a circuit, and state whether the power factor is leading or lagging.
3.
Predict the effect of using shunt capacitors to change the power factor or to control
voltage.
4.
Draw a phasor diagram for the line and phase values of voltage and current for a threephase system.
5.
Convert a balanced delta load to an equivalent wye load.
6.
Convert a balanced delta source to an equivalent wye source
7.
Draw the per-phase equivalent circuit if you are given a three-phase system one line
diagram.
8.
Apply per-phase analysis to a balanced three-phase circuit.
Readings
Bergen & Vittal, Power Systems Analysis, 2nd ed., chapter 2.
Schedule
Class
1 1/18 We
2 1/20 Fr
3 1/23 Mo
4 1/25 We
5. 1/27 Fr
6. 1/30 Mo
Lecture Topics
Pages
Introduction; review of ac circuits
1-23
Power triangle; conservation of complex
power; power factor and
its correction
23-35
Balanced three-phase voltage and
current; Wye and delta loads
35-43
Per-phase analysis
43-46
Three-phase power; power triangle
46-47
Examples
Practice Problems
2.1, 2. 3, 2.4, 2.5, 2.7, 2.10
Assignment 1
To be collected; see handout.
1/31/06