Stabilizing torsional oscillations using a hunt reactor controller

Results of a study on the application of shunt reactors for the damping of torsional oscillations that occur in a power system containing series-capacitor compensation are presented. The IEEE Second Benchmark Model, system-1 is used to investigate the benefits of the utilization of modulated reactive power in suppressing unstable subsynchronous resonance (SSR) modal interactions. A set of shunt reactors is connected to the generator bus of the affected synchronous machine whose shaft is directly coupled to the turbine system of the benchmark model. In order to stabilize all the torsional modes, a unified approach based on modal control theory is proposed for the design of a shunt reactor controller, which is essentially a dynamic output compensator. To demonstrate the effectiveness of the damping enhanced by the proposed scheme, eigenvalue analysis for different loading conditions and sensitivity analysis for controller parameters are performed