Nonlinear optimal TCSC control in comparison to PSO based conventional design in small signal stability enhancement

This paper presents a nonlinear control scheme for the Thyristor Controlled Series Compensator (TCSC) in order to improve small signal stability in a Single Machine Infinite Bus (SMIB) power system. The affine nonlinear model of a SMIB system is exactly linerized applying feedback linearization method where the optimal control law is estimated by the Linear Quadratic Regulator (LQR) principle. The performance of proposed nonlinear control scheme is compared with the performance of a conventional controller, whose parameters are tuned through a novel soft computation method, Particle Swarm Optimization (PSO). The results of small signal stability analysis have been presented employing time domain analysis. It has been observed that, in comparison with the optimally tuned conventional controller, significant improvements of small signal performance in the test power system are achieved by the proposed nonlinear control strategy.