A comparative study of the implementation of STATCOM and SVC on DFIG-based wind farm connected to a power system

Abstract

This paper investigates and compares the implementation of two FACTS (Flexible AC Transmission System) devices to overcome the voltage stability issue for Doubly Fed Induction Generator (DFIG)-based wind farm. The study includes the implementation of both a static synchronous compensator (STATCOM), and the static var compensator (SVC) as dynamic reactive power source at the point of common coupling to maintain stable voltage. The system study is performed using the MATLAB/Simulink and the results show that the both devices improve the transient voltage stability and therefore help the DFIG-based wind farm to remain in service during grid faults. The performance of the two devices in terms of time response, the injected amount of reactive power and the application cost was studied at length. During grid faults, the RSC is blocked and restarts when the fault is cleared and the PCC voltage is reestablished. The control schemes of the DFIG, Rotor Side Converter(RSC), Grid Side Converter (GSC), and the FACTS devices have been suitably designed and coordinated. It was concluded that the application cost of both devices varies depending on the fault type and location. STATCOM becomes a very cost effective solution when the required injected reactive power is not large, such as for a single-line-to-ground fault and lower voltage sag. The static VAR compensator (SVC), on the other hand, becomes very attractive application (cost effective) when a large amount of reactive power needs to be injected, such as three-phase fault conditions.