Optimal Allocation of Multi-Type FACTS Devices for Security and System Loadability Enhancement

The Flexible AC transmission System (FACTS) devices, such as, thyristor controlled series compensators (TCSC) and Static Var Compensator (SVC) can be used to enhance power system performance. To achieve a better use of FACTS devices and because of their considerable costs, it is important to limit the number of theses controllers and locate them optimally in the power system. Firstly, we have applied optimization technique, namely, NSGA-II, to find out the optimal number of multi-devices of TCSC and SVC in order to improve the system loadabilty and to ensure the steady state security of the network. Secondly, we performed a contingency analysis procedure based on severity index (SIL) to identify and classify the most severe line contingencies. Then, we determined the optimal placement and parameter setting of FACTS devices in power system by using the above optimization approach to alleviate the line overloads. To ensure the robustness and effectiveness of the proposed method, N−1 contingency analysis and the stress of power system are considered. The optimization problem presented in this paper aims at reducing FACTS installation cost and decreasing total real power losses. Simulations are performed on IEEE 30-bus test system.