Computing the damping of subsynchronous oscillations due to a thyristor controlled series capacitor

We extend eigenvalue analysis of subsynchronous resonance (SSR) to include thyristor switchings. The eigenvalue computation takes account of the time variations and nonlinearities of both the thyristor switchings and the generator. An example is presented using the IEEE first benchmark SSR model. The paper contributes an accurate method to compute the damping of the SSR modes with a TCSC.