15/05/2021
ELK 322E Power Transmission Systems
CRN 21770
20120-2021 Spring Semester
HOMEWORK 03
Due date: 23/05/2021
Question:
The one-line diagram of a three-phase system shown above:
a) Find the bus admittance matrix, for this case consider the generator are injected the I G1 and
IG2 currents and loads drawn the currents ID3 and ID4.
b) Write the expression for the real power at bus 2 and real and reactive power at bus 3.
c) Let assume that the Newton-Raphson method is used for power flow analysis. Complete
the table given below.
Note: In this problem the solution of the power flow is not asked, but necessary steps for a
power flow analysis are asked, such as obtaining the bus admittance matrix, obtaining
power the balance equations (but in this problem for bus-2 and bus-3 equation are enough),
and classification of buses.
Bus no.
Bus Type
Knowns
Unknows
1
Slack bus
|V1|, 1
P1 and Q1
2
3
4
1
2
P1
P2 = 0.8 pu
z12= j0.2 pu
G1
G2
V1 = 1.02pu
V2 = 1.012pu
z13 =j0.4 pu
z24= j0.1 pu
z34= j0.2 pu
3
V3 = |V3|3pu
Load 1
SD3 = 0.9+ j0.6 pu
4
V4 = |V4|4pu
Load 2
SD4 = 0.7+ j0.4 pu
Fig. The one-line diagram of a three-phase system