Improve Sub-Synchronous Resonance (SSR) damping using a STATCOM in the transformer bus

Sub-synchronous resonance (SSR) oscillations in long transmission line brings to failure of the turbine shaft. Static compensator (STATCOM) is a multifunctional FACTS device which its ability depend on its location on transmission line. In this paper, a controller is proposed and designed for STATCOM in transformer bus to damping SSR in all operation points. The controller is designed based on speed deviation damping signal. In addition to SSR damping, STATCOM implemented in the transformer bus can control line active power and other dynamical events such as first swing stability and power oscillations. Eigenvalue analyses and nonlinear simulations in PSCAD/EMTDC software are employed to illustrate the performance of the proposed controller and the STATCOM. Simulation results approve the proposed scheme capability in SSR damping at different level of series compensations of the transmission lines.