Mitigation of voltage dips and swells in grid-connected wind energy conversion systems

This paper investigates two methods for mitigation of voltage dips and voltage swells in a grid to which a wind energy conversion system (WECS) is connected. The two mitigation methods are the dynamic voltage regulator (DVR), and the static compensator (STATCOM). The wind energy system employs permanent magnet synchronous generator (PMSG). It is well known that the voltage dips affect the PMSG adversely, leading to unlimited increase in its speed. Hence, quick voltage dip mitigation is required. The responses of both DVR and STATCOM to voltage dips as well as voltage swells are investigated and compared. Also the active and reactive power behaviors in each system during and after fault recovery are investigated. The simulation results compared for voltage dips and voltage swells show less harmonic contents for the system employing the DVR. However, the response of the two systems to faults are comparable.