Static Voltage Stability Analysis Based on PSS/E - Intelligent Computing for Sustainable Energy and Environment - page 197

3 Example
The IEEE 30 Bus Test Case represents a portion of the American Electric Power
System (in the Midwestern US) in December, 1961. The test case has buses at
either 132 KV or 33 KV. This paper studies steady state voltage stability base
on IEEE 30 BUS Test Case. IEEE 30 Bus Test Case diagram is illustrated as
Fig.2.
Fig. 2. IEEE 30 Bus Test Case diagram
A. Contingency Ranking
The IEEE 30 Bus Test Case includes 5 generators and 35 non-transformer
branches. Among these lines, 13 branches are at 132 KV voltage level, and 22
branches are at 33 KV voltage level. Table 1 shows the result of five severe
contingency ranking.
In table 1, the severe branch contingencies mainly occur at high voltage level.
That is, the branch contingencies at high voltage level have a large impact on
system voltage stability.
B. Base Case
Fig.3 gives the PV curve and QV curve of bus 26 at base case. From Fig.3.a, it
can be seen that the bus voltage continues to decrease as the transmission power
increase. From Fig.3.b, an increase in Q is accompanied by an increase in V, the
operation on the right side of the QV curve is stable, whereas the operation on
the left side is unstable. Thus Fig.3 verifies the model mentioned in section 2.
Table 2 shows the former eight buses' reactive power margin in order in IEEE
30 Bus Test Case. It shows that weak grid areas mainly occurs on the 33 KV