Analysis of subsynchronous torsional interactions with static Var Compensators

The main purpose of this paper is to investigate the mechanism of torsional interaction with SVC. For no loss of generality, a single machine infinite bus system is studied in this paper. A simplified damping torque analysis is presented to get an insight into the torsional interaction caused by the SVC controller. The expression of electrical damping torque (T_De), which estimate whether SSTI occurs or not, is proposed. The influence of the controller parameter of SVC on T_De, which is deduced in a simplified damping torque analysis, is also studied.