Enhancement of Power System Stability employing cat swarm optimization based PSS

Low frequency oscillations are observed when large power systems are interconnected by relatively weak tie-lines. Power System Stabilizers (PSS) are incorporated in the excitation system of the generators to enhance damping of these low frequency oscillations. In this paper, the design of multiple PSS in a multi-machine power system (MMPS) using Cat Swarm Optimization (CSO) algorithm has been proposed. The design problem of the PSS has been formulated as an optimization problem and CSO has been employed to search for optimal controller parameters. It has been shown that the stability performance of the system can be improved by minimizing the eigenvalue based objective function comprising of the damping factor and the damping ratio of the poorly damped electromechanical modes. Eigenvalue analysis and nonlinear simulation results have also been presented for various loading conditions and system configurations to show the effectiveness and robustness of the proposed controllers and their ability to provide efficient damping of low frequency oscillations.