Restraining SSR with CDRPF-signal supported static var system

A new supportive signal namely Combined Derivative of Reactive Power and Bus Frequency (CDRPF) in SVS for alleviating torsional oscillations due to SSR is developed. The IEEE first benchmark model incorporating midpoint located SVS is considered as a test system. The effect of CDRPF-SVS supportive signal for restraining torsional oscillations due to SSR is illustrated. An analysis through eigenvalues of the linearized series compensated power system is demonstrated once incorporating the proposed supportive signal and once without any supportive signal. It is found that the unstable torsional modes are effectively eliminated with the proposed supportive signal. Also, the performance of the proposed supportive signal is assessed for the non-linear system model under large disturbance conditions. The concept of designing of proposed supportive signal has been implemented by using a detailed system model reflecting the system dynamics of various power system components accurately. Results of simulation demonstrate the effective damping of torsional oscillation due to subsynchronous resonance (SSR) under severe conditions and confirm the efficacy of the supportive input signal under consideration.