Power System Analysis (EELE 4351)

site.iugaza.edu/emp/ajasser Assad Abu-Jasser, PhD Electric Power Engineering The Islamic University of Gaza ajasser@iugaza.edu.ps site.iugaza.edu/emp/ajasser

Chapter 1 Basic Concepts

Single-Phase Circuits Instantaneous, Effective and Phasor

Single-Subscript Notation

Double-Subscript Notation

Power in Single-phase AC Circuits

Complex Power and Power Triangle

Direction of Power Flow

Example 1.1 Two ideal voltage sources designated as machine 1 and 2 are connected as shown. E1=100 V with phase angle of 0o, E2=100 V with phase angle of 30o and Z=0+j5 Ω, determine (a) whether each machine is generating or consuming real power and the amount, (b) whether each machine is receiving or supplying reactive power and the amount, and (c) the P and Q absorbed by the impedance

Balanced 3-Phase Circuits

Balanced 3-Phase Circuits a-Operator

Balanced 3-Phase Circuits Line and Phase Voltages

Example 1.2 In a balanced three-phase circuit the voltage Vab is 173.2 with a phase angle of 0o V. Determine all the voltages and the currents in a Y-connected load having ZL=10 Ω and a phase angle of 20o. Assume abc sequence.

Delta-Connected Load

Per-Phase Equivalent Circuit

Example 1.3 The terminal voltage of a Y-connected load consisting of three equal impedances of 20 Ω with a phase angle of 30o is 4.4 kV line-to-line. The impedance of each of the three lines connecting the load to a bus at a substation is ZL=1.4 Ω with a phase angle of 75o. Find the line-to-line voltage at the substation bus.

Power In Balanced 3-Phase Circuits

Per-Unit Quantities

Example 1.4 The terminal voltage of a Y-connected load consisting of three equal impedances of 20 Ω with a phase angle of 30o is 4.4 kV line-to-line. The impedance of each of the three lines connecting the load to a bus at a substation is ZL=1.4 Ω with a phase angle of 75o. Find the line-to-line voltage at the substation bus. Find the solution by working in per-unit on a base of 4.4 kV, 127 A.

Changing Base of Per-Unit Quantities

Example 1.5 The reactance of a generator designated X” is given as 0.25 per-unit based on the generator nameplate rating of 18 kV, 500 MVA. The base for calculation is 20 kV, 100 MVA. Find X” on the new base.

Node Equations

The Single-Line or One-line Diagram

Impedance and Reactance Diagrams

End Of Chapter One