Mitigation of Sub Synchronous Resonance in Series Compensated Transmission Line using Distributed Static Series Compensation FACTS Device

Abstract

The turbine-generator system has own torsional natural frequencies due to the physical properties of long multi-element shaft. When a Steam turbine generator is connected with long series compensated transmission line following three phase to ground fault, an adverse result takes place known as Sub Synchronous Resonance (SSR). Because of this, the torsional oscillation will be delivered between the two ends of the generator- exciter shaft and if not damped properly, it may cause failure of the turbine or in other word it breaks the shaft. It was found from the research that SSR was the main cause of the shaft failure in 1970 at the Mohave plant in Southern Nevada, so now a day’s substantial research is going on constructive SSR mitigation measures. In this research work, to mitigate SSR, one of the D-FACTS devices namely distributed static series compensator (DSSC) facts device is used. The IEEE second benchmark system with and without DSSC should studied for sub synchronous resonance phenomenon and the simulation models are developing in MATLAB.