Question

A voltage controlled bus is treated as a load bus in subsequent iteration when its

Answer 1

If a voltage bus is treated as a load bus, it means that its reactive power limits are violated.

Explanation:

All values are in per unit basis.

Let bus-2 be a PV bus with P and |V| specified as 0.6 and 1.05, respectively. The bus reactive power limits are Q2max = 0.3 and Q2min = -0.1

Case 1: Upon calculating Q2 with the available voltage values, we find that it is - 0.2.

Q2 = -0.2, which is Q2 < Q2min. Hence a limit violation has occurred.

So we can take bus-2 as load bus with Q2 = Q2min for this iteration.

Case 2: Upon calculating Q2 with the available voltage values, we find that it is 0.65.

Q2 = 0.65, which is Q2 > Q2max. Hence a limit violation has occurred.

So, we can take bus-2 as load bus with Q2 = Q2max for this iteration.