A multi-objective multi-case optimization approach for allocation of FACTS devices to enhance static security, efficiency and line voltage profiles

This paper presents an approach based on fuzzy decision making and genetic algorithm to solve a multi-objective multi-case problem of optimal allocation of flexible AC transmission system (FACTS) devices. In addition to power transmission loss and static security indices of line power flows and bus voltages, the reactive power absorbed by transmission lines is considered as another objective so as to correct voltage profiles on lines of higher series reactance. Two main features of the approach are: a) bus voltage deviations and line overloads are individually avoided as much as possible by imposing stringent constraints through defining appropriate membership functions, and b) in addition to system base case, a number of critical contingency cases obtained from a contingency analysis/ranking method are included directly in the optimization process. The variables to be optimized consist of locations and types of FACTS devices, their settings for base case and regarded contingency cases. Simulations are performed on the standard IEEE 30-bus system and results are discussed.