Analysis of SSR Mitigation Using Gate Controlled Series Capacitors

The gate-controlled series capacitor (GCSC) was proposed initially for series compensation of transmission line to control power flow. Then, it was shown that, in some conditions, the GCSC could damp SSR even if no specific controller is used. In the present work, the GCSC was tested for mitigation of subsynchronous resonance (SSR) including a control loop. A detailed analysis of the use of the GCSC with turn-off angle control for SSR damping is presented. The power system used for the analysis of this phenomenon was the first IEEE benchmark. The actual possibility of eliminating SSR was verified by digital simulation using the ATP/EMTP (alternative transients program /electromagnetic transients program). As a result is it possible to say that GCSC is a powerful device for controlled series compensation both for power flow control and SSR damping