A comparative study in power oscillation damping by STATCOM and SSSC based on the multiobjective PSO algorithm

To improve the damping of power system oscillations by supplementary controller design for the static synchronous series compensator (SSSC) and static synchronous compensator (STATCOM), a multiobjective function based on the particle swarm optimization (PSO) algorithm for solving this optimization problem is introduced. The presented objective function includes the damping factor and the damping ratio of the lightly damped and undamped electromechanical modes. These controllers are adjusted to concurrently transfer the lightly damped and undamped electromechanical modes to a recommended region in the s-plane. For this purpose, the reduced linearized Phillips-Heffron model of the power system with a single machine and infinite bus, integrated with a STATCOM and a SSSC, is used. In this paper, to solve the mentioned optimization problem, the PSO technique is used. It is a robust stochastic optimization technique and has a high capability for discovering the most optimal results. The different loading conditions are simulated and the effects of these flexible alternating current transmission system controllers over the rotor angle and rotor speed deviations are studied. Simulation results reveal that the SSSC's performance is better than that of the STATCOM and it provides higher damping than the STATCOM. MATLAB/Simulink software is used for running the dynamic simulations.