LQR tuning of power system stabilizer for damping oscillations

Abstract

Power System Stabilizers (PSS) are added to excitation systems to enhance the dampingduring low frequency oscillations. In this paper, the design of PSS for single machine connected to aninfinite bus using optimal control techniques is considered. A method for shifting the unstable open-loop poles to optimum positions is presented. In each step of this approach, I solve a first-order or asecond-order linear matrix Lyapunov equation for shifting unstable pole. This presented methodyields a solution, which is optimal with respect to a quadratic performance index. The attractivefeature of this method is that it enables solutions to complex problem to be easily found withoutsolving any non-linear algebraic Riccati equation. The gain feedback is calculated one time only andit works over wide range of operating conditions. A comparison between the effect of the PSS basedon conventional approach, and the proposed Linear Quadratic Regulator (LQR ) is reported usingMATLAB/SIMULINK for simulation.