Design of Nonlinear Optimal Excitation Controller in Comparison with PSO based Conventional PSS in Power System Stability Improvement

Abstract

This paper focuses on the design of a nonlinear optimal excitation controller in order to improve dynamic stability in a Single Machine Infinite Bus (SMIB) power system. The affine nonlinear model of an SMIB power system is exactly linerized applying feedback linearization method where the optimal control law has been estimated by the Linear Quadratic Regulator (LQR) principle. The performance of the proposed nonlinear excitation control scheme is compared with the performance of the conventional PSS. The parameters of the conventional PSS are designed through a novel soft computation technique, Particle Swarm Optimization (PSO). The results and effectiveness of the design have been presented employing time domain analysis for a typical fault scenario of the study system. It has been observed that, in comparison to the PSO based PSS, significant improvements in dynamic stability of the test power system are achieved by the proposed nonlinear excitation control strategy.