Designing of supplementary controller for statcom for mitigation of sub-synchronous resonance in series compensated power system

In FACTS devices supplementary signals are widely used to enhance damping and mitigation of Subsynchronous Resonance in Power System. Subsynchronous Resonance occurs due to series capacitor in the Power Systems. High value of series capacitive reactance may destabilize low frequency mode which is more dangerous. In this paper modeling of STATCOM with IEEE first benchmark model is presented. Then a supplementary signal is developed which is capable to make the system stable for all critical values of series compensation. The eigenvalues are presented for all four critical values of series compensation.