Application of a STATCOM for damping subsynchronous oscillations and transient stability improvement

This paper investigates the effect of STATCOM in stabilising multi-mode torsional oscillations of sub-synchronous resonance (SSR) of a large turbine-generator set. The study is performed on system-1 of the second IEEE benchmark model for computer simulation of subsynchronous resonance. The application of the STATCOM in improving transient stability in power systems is described as well. EMTDC/PSCAD is used to simulate the system under study. Due to its simplicity, robustness and ease implementation, proportional integral (PI) controller along with auxiliary feedback signals are used to control the inverter firing angle and hence control the reactive power exchange between the AC system and the STATCOM.