Research ArticleApplication of polynomial control to design a robust oscillation-damping controller in a multimachine power system

•The best signal for SVC-based SDC (PI controller) is chosen using accurate investigation based on the HSVs and RHP-zeros.•Both load variation and changes in power system configuration have been considered as sources of uncertainty (changing of operating conditions).•Robust stability and robust performance (desired Gm, Pm and bandwidth) have been considered to design a desirable damping controller. The proposed method is simple and straightforward for the PI controller design.

This paper addresses the application of a static Var compensator (SVC) to improve the damping of interarea oscillations. Optimal location and size of SVC are defined using bifurcation and modal analysis to satisfy its primary application. Furthermore, the best-input signal for damping controller is selected using Hankel singular values and right half plane-zeros. The proposed approach is aimed to design a robust PI controller based on interval plants and Kharitonov׳s theorem. The objective here is to determine the stability region to attain robust stability, the desired phase margin, gain margin, and bandwidth. The intersection of the resulting stability regions yields the set of kp-ki parameters. In addition, optimal multiobjective design of PI controller using particle swarm optimization (PSO) algorithm is presented. The effectiveness of the suggested controllers in damping of local and interarea oscillation modes of a multimachine power system, over a wide range of loading conditions and system configurations, is confirmed through eigenvalue analysis and nonlinear time domain simulation.