# ECE 4300/5300 ELECTRIC POWER SYSTEMS SPRING 2016 HW #3 DUE: 02/22/2016 NOTE**

```ECE 4300/5300 ELECTRIC POWER SYSTEMS SPRING 2016 HW #3
DUE: 02/22/2016
NOTE**: There are answers to some of the problems at the ends of the course
textbooks. To get full credit, you must show how you got your answers or you will
1.
Consider a 3-phase system with the one-line diagram shown in Fig P1.1. Choose a common
100 MVA 3-phase power for the entire system and 138-kV base in the transmission line.
G1
T1
k
13.2 kV
(a)
(b)
(c)
2.
l
T2
ZL = 10 + j100 Ω
5 MVA
13.2 / 132Y kV
XT1 = 10%
m
L1
n
10 MVA
138Y / 69 kV
XT2 = 8%
Fig. P1.1
(i)
Determine the base kV in the generator G1 circuit.
(ii)
Determine the base kV in the load L1 circuit.
Draw the positive-sequence reactance diagram showing all impedances in per unit.
Determine the generator current, the transmission line current, the load current, the
The Fig. P2.1 shows a one-line diagram for two 3-phase transformer banks connected in
parallel. Three single-phase transformers are connected to form the 3-phase transformers.
The single-phase transformer in the two banks are specified as follows:
Y - Y bank:
Y -  bank:
n = 10, X = 0.05 Ω;
n = 103, X = 0.05 Ω
The line-neutral voltage at bus 1 has a magnitude of 8 kV. The load at bus 2 is Y-connected;
o
each impedance, Zload = 100/0 Ω. Assume that the phase of V1 is zero.
I1
G1
Y-Y
I’1
Is
I2
V1
(a)
(b)
3.
Y-
Fig. P2.1
Draw per phase equivalent circuit.
Determine Is, I1, I2, I’1, I’2, and Iload.