Analysis of a centralized control strategy in mitigating inter-area power oscillations

The development of Wide Area Measurement System (WAMS) technology has allowed the use of centralized control algorithms for damping inter-area oscillations in power systems. In this paper, Linear Quadratic Regulator (LQR) method is used to design a centralized controller that together with the existing power system stabilizers improves the damping of inter-area power oscillations. The focus of this paper is on studying how changes in power system operating conditions and grid topology affect the performance of the centralized controller. The controller performance is studied using modal analysis and nonlinear time domain simulations and compared against a conventional control strategy where only local power system stabilizers are used. The modal analysis of the closed loop system shows improvement in damping even after changes in operating conditions. However, nonlinear time domain simulations show that the controller performance deteriorates after changes in system operating conditions and grid topology.