Multimachine power system stabilizer tuning using Harmony Search algorithm

In this paper, Harmonic Search Optimization (HSO) algorithm is implemented for tuning of multimachine Power System Stabilizer (PSS) to die out local and inter-area mode oscillations to enhance small signal stability. The performance of controller is compared with Particle Swarm Optimization (PSO) technique. A multi-objective eigenvalue based optimization problem involving maximization of damping factor and damping ratio is formulated for designing the PSS parameters. The parameters of the proposed PSS are optimized to transfer the unstable or lightly damped eigenvalues to a D-shape sector in left half of the s-plane. The performance of the proposed stabilizer is evaluated on 10-machine, 39-bus New England power system. The effectiveness of HSO based PSS (HSOPSS) is demonstrated by using the eigenvalue analysis and non-linear simulations. Moreover, the robustness of HSOPSS is evaluated by the performances indices results that assure well damped controller compare to PSO based PSS (PSOPSS) under varying loading conditions, severe line outage and three-phase short circuit faults.