Faults at bus (n) in Problem 9.5 are of interest (the instructor selects (n=1), 2,3 , or
Question:
Faults at bus \(n\) in Problem 9.5 are of interest (the instructor selects \(n=1\), 2,3 , or 4). Determine the Thévenin equivalent of each sequence network as viewed from the fault bus. Prefault voltage is 1.0 per unit. Prefault load currents and \(\Delta-Y\) phase shifts are neglected.
Problem 9.5
Equipment ratings for the four-bus power system shown in Figure 7.14 are given as follows:
Generator G1: \(\quad 500 \mathrm{MVA}, 13.8 \mathrm{kV}, \mathrm{X}_{d}^{\prime \prime}=\mathrm{X}_{2}=0.20, \mathrm{X}_{0}=0.10\) per unit
Generator G2: \(750 \mathrm{MVA}, 18 \mathrm{kV}, \mathrm{X}_{d}^{\prime \prime}=\mathrm{X}_{2}=0.18, \mathrm{X}_{0}=0.09\) per unit
Generator G3: \(1000 \mathrm{MVA}, 20 \mathrm{kV}, \mathrm{X}_{d}^{\prime \prime}=0.17, \mathrm{X}_{2}=0.20, \mathrm{X}_{0}=0.09\) per unit
Transformer T1: \(500 \mathrm{MVA}, 13.8 \mathrm{kV} \Delta / 500 \mathrm{kV} \mathrm{Y}, \mathrm{X}=0.12\) per unit
Transformer T2: \(750 \mathrm{MVA}, 18 \mathrm{kV} \Delta / 500 \mathrm{kV} \mathrm{Y}, \mathrm{X}=0.10\) per unit
Transformer T3: \(1000 \mathrm{MVA}, 20 \mathrm{kV} \Delta / 500 \mathrm{kV} \mathrm{Y}, \mathrm{X}=0.10\) per unit
Each line: \(\quad \mathrm{X}_{1}=50\) ohms, \(\mathrm{X}_{0}=150 \mathrm{ohms}\)
The inductor connected to generator G3 neutral has a reactance of \(0.028 \Omega\). Draw the zero-, positive-, and negative-sequence reactance diagrams using a \(1000-\mathrm{MVA}, 20-\mathrm{kV}\) base in the zone of generator G3. Neglect \(\Delta-Y\) transformer phase shifts.
Figure 7.14
Step by Step Answer:
Power System Analysis And Design
ISBN: 9781305632134
6th Edition
Authors: J. Duncan Glover, Thomas Overbye, Mulukutla S. Sarma