Non-controlled fault current limiter to improve fault ride through capability of DFIG-based wind turbine

In this paper, a non-controlled fault current limiter (FCL) is proposed to improve fault ride through capability of doubly fed induction generator (DFIG)-based wind turbine. Cooperative operation of chopper circuit and the non-controlled FCL, which is located in rotor side of the DFIG, is studied. It is demonstrated that locating the proposed topology in the rotor side is effective from leakage coefficient point of view in limiting transient over currents rather than stator side. Furthermore, it is shown that, by obtaining optimum non-superconducting reactor value, rate of fault current change is limited to lower than maximum rate of current change in semiconductor switches of the DFIG's converters during fault. Design methodology of non-superconducting reactor value is investigated. Operation of the non-controlled FCL in the rotor side is compared to crowbar protection scheme and results will be discussed. PSCAD/EMTDC software is employed to simulate the proposed scheme and prove its effectiveness.