Stability improvement of power systems connected with developed wind farms using SSSC controller

Abstract

This paper studies the performance of SCIG wind farm, DFIG wind farm, and a combined wind farm (CWF) during three-phase grid fault. The SCIG and DFIG wind farms are equipped with Static Synchronous Series Compensator (SSSC) whereas the combined wind farm did not have one. Since the CWF is composed of an equal number of Double Feed Induction Generators (DFIGs) and Squirrel Cage Induction Generators (SCIGs), it incorporated the main advantages of both types of generator. More specifically, the SCIG has a lower cost, but its drawback lies in its negative impact on system stability, especially when it operates without a shunt compensator. On the other hand, the DFIG, though more expensive, is better able to maintain the stability of the system. The SCIG and DFIG wind farms are equipped with SSSC controller to control the active and reactive line power flow. The results of a comparative study of DFIG and SCIG wind farms with SSSC and combined wind farm without SSSC during a three-phase grid fault showed that even though the SSSC improved the performance of the DFIG and SCIG wind farms, the CWF without the SSSC controller is found to have the best performance. The stability of the three wind farms is examined using Voltage Stability Index (VSI). All of the test scenarios are simulated with MATLAB. Keywords: Combined wind farm, Double feed induction generator, Squirrel cage induction generator, FACTS, SSSC