Suppression of common torsional mode interactions using shunt reactor controllers

The paper presents the results of a study on the utilization of shunt reactors for the damping of common torsional mode interactions of a power system containing series-capacitor compensation. The IEEE Second Benchmark Model, system-2, which has two sets of nonidentical turbine-generators connected to an infinite bus via a common series-capacitor compensated transmission line, is employed to investigate the possible unstable subsynchronous resonance (SSR) modal interactions which can be suppressed by using reactive power compensation. A set of shunt reactors are proposed and connected to the studied system and a unified approach based on modal control theory is employed to design shunt reactor controllers in order that all SSR modes in the system can be stabilized. For clearly demonstrating the effectiveness of the proposed scheme, SSR mode eigenvalues under different loading conditions and sensitivity analysis of shunt reactor controllers´ parameters are performed. Dynamic responses of the nonlinear system simulation under a torque disturbance on a generator shaft and a severe three-phase short-circuit fault at an infinite bus are also carried out