Frequency response of the thyristor controlled series capacitor

The small signal method is used to derive the frequency response of a thyristor controlled series capacitor (TCSC). A small signal current is injected into TCSC, then the voltages and currents of TCSC and their spectral analysis is presented, and the frequency response of TCSC is analyzed. The study is important for subsynchronous resonance (SSR) as well as other harmonic related studies and the method maybe applied to the analysis of other FACTS devices.