Multi-objective FACTS placement using improved harmony search optimization

Abstract

Optimal placement of FACTS devices attempts to improve power transfer, minimize active power loss, enhance voltage profile and improve voltage stability, thereby making the operation of power systems more flexible and secured. The classical methods experience difficulties in solving the FACTS placement problem (FPP) with discontinuous functions and may diverge or result oscillatory convergence. Besides the number of FACTS devices for placement should be given as an input while solving the problem. The solution methods then attempts to forcefully place all the specified number of devices in the power system, but in reality, the system may require an optimal number of FACTS for placement. The application of swarm-intelligence based optimization algorithms strives to overcome the drawbacks of classical methods. This paper presents a new solution method for FACTS placement problem using improved harmony search optimization (IHSO) with a newly suggested dissonance mechanism that avoids badly composed music, with a view of avoiding the sub-optimal solutions. Besides, the method requires to specify only the maximum number of FACTS devices for placement and places only the optimal number of devices within the specified maximum number of devices. The paper also includes simulation results of three IEEE test systems for exhibiting the superiority of the proposed method.