Simulation and Analysis of Sub Synchronous Resonance in a Series Compensated Transmission System

Abstract

Series compensation of a transmission line is necessary as it increases the power transfer capability of a transmission line. Employing series compensation also leads to phenomenon of sub synchronous resonance (ssr) wherein the electrical and mechanical natural frequencies match and exchange energy leading to excitation of natural torsional modes of the turbine generator unit. This leads to mechanical fatigue of the shaft on which turbine and generator are connected. This paper analyses the sub synchronous resonance in series compensated transmission system. The system is simulated in MATLAB/SIMULINK. The results clearly show the adverse effects of series compensation in some operating conditions. Therefore, an effective mean of protection must be employed in the system to tackle the impacts of series compensation during undesired operating conditions.

Keywords: Series compensation, sub synchronous resonance (SSR), load dynamics, torsional modes, negative damping