A supplementary damping controller of TCSC for mitigating SSR

The thyristor controlled series capacitor (TCSC) is subsynchronous resonance (SSR) neutral in itself. But in a hybrid system which includes both conventional fixed series compensation and TCSC, disturbances may still excite torsional modes. This paper aims to design a supplementary damping controller for the hybrid system to mitigate the SSR. The method and procedure for the syntheses of the controller is presented. The test signal method is adopted to analyze the SSR damping characteristics with the TCSC auxiliary controller. Time-domain simulation with PSCAD/EMTDC indicates that the proposed controller is effective to mitigate SSR.