Effects of FCL on operation of SEF-DFIG in wind turbine systems during grid fault

Abstract

During last decade, the concept of a variable speed wind turbine equipped with doubly fed induction generator (DFIG) has received increasing attention due to its noticeable advantages over other wind turbine generator concepts. New configuration of DFIG is single external feeding of DFIG (SEF-DFIG) where a rotor side converter (RSC) replaces the back to back variable frequency converter (VFC) in the conventional DFIG. The main issue of wind turbines that equipped DFIG and SEF-DFIG is the grid faults or low voltage ride through capability. In this paper, a new solution for uninterrupted operation of wind turbine driving a SEF-DFIG has been proposed during fault condition in the grid. A fault current limiter (FCL) is placed in series with the rotor circuit. During fault condition FCL enters a impedance in the rotor circuit to inhabit increasing of current in the rotor circuit. When the fault is cleared the FCL bypasses the impedance. A static synchronous compensator (STATCOM) has been applied for supplying required reactive power in faults and steady states. Capability and modeling accuracy of the proposed method confirmed with simulating a sample power system in PSCAD/EMTDC software.