Analysis of subsynchronous resonance with three level twelve-pulse VSC based SSSC

The paper presents the analysis and simulation of a series compensated system with a static synchronous series compensator (SSSC) as a part of the total compensation. The objective is to investigate the subsynchronous resonance (SSR) characteristic of the combined system. The IEEE first benchmark model (FBM) is considered for the analysis. The active series compensation is provided by a three level twelve pulse SSSC. The modelling and control details of a three level voltage source converter (VSC) based SSSC are discussed. The analysis of SSR with SSSC is carried out based on a frequency domain method, eigenvalue analysis and transient simulation. The frequency domain method considers the D-Q model of SSSC for the computation of damping torque for a quick check in determining torsional mode stability.