Optimal placement of UPFC for maximizing system loadability and minimizing active power losses in system stability margins by NSGA-II

This paper presents application of a new variant of Genetic Algorithm specialized in multi-objective optimizations problem known as Non-dominated Sorting Genetic Algorithm II (NSGA-II) to obtain optimal allocation of one type of FACTS controllers namely: Unified Power Flow Controllers (UPFC) for improving the performance of the power system. Two objective functions are simultaneously considered as the indexes of the system performance; maximization of system loadability in system stability margins (voltage stability index and line stability factor) and minimization of active power losses in transmission line by considering installation cost of UPFC controller. The UPFC controller are modelled and incorporated in the Newton Raphson Power flow problem. Simulation studies are undertaken on a standard IEEE 30-bus test system and a practical Java-Bali 24-bus of Indonesian system. Results demonstrate that the static performances of the power system can be effectively enhanced due to the optimal allocation of single UPFC controller.