Kalman Filter Based Detection and Mitigation of Subsynchronous Resonance with SSSC

In a long transmission line the use of static series synchronous compensation (SSSC) with fixed series capacitor enables fast control of power flow. There is a potential risk of subsynchronous resonance (SSR) due to the series capacitor. In this paper, we propose to use the Kalman filter (KF) for state estimation of subsynchronous components present in series compensated line and the mitigation of SSR. This novel KF based SSR damping controller is referred to as KF-damping controller. The design of KF-damping controller is based on the magnitude of damping torque in the range of torsional mode frequencies. We apply the genetic algorithm to optimize the controller parameters. The proposed KF-damping controller is highly frequency selective and effectively suppresses subsynchronous components of line current in the presence of close frequency oscillations. Analytical and simulation results at various system operating conditions demonstrate the effectiveness and robustness of the proposed KF-damping controller in mitigating SSR.