Design of nonlinear and conventional STATCOM controllers to mitigate transient stability of a power system

This paper proposes a novel scheme to design a nonlinear optimal feedback controller for a STATCOM in order to enhance transient stability of a power system. The method of exact linearization with Brunovsky normal form is employed to formulate the nonlinear control law. The optimal gain matrix of the feedback controller is estimated applying Linear Quadratic Regulator (LQR) approach. The performance of this nonlinear controller is compared with a conventional lead-lag based STATCOM controller in presence of different operating scenarios of a Single Machine Infinite Bus (SMIB) power system. The tuning parameters of the conventional controller are optimized through a popular heuristic computation technique, Particle Swarm optimization (PSO). From the simulation results it has been observed that both the conventional and the nonlinear controllers effective in mitigating transient stability but the performance of the nonlinear controller is found to be more satisfactory and better than the PSO based conventional controller.