Enhancement of LVRT Capability of DFIG-based Wind Turbines by Superconducting Fault Current Limiter

In this paper, a resistive-type superconducting fault current limiter (SFCL) besides an efficient control strategy and optimal parameter design approach is suggested to improve low voltage ride-through (LVRT) capability of DFIG wind turbines. The proposed structure is different from conventional hardware based LVRT solutions from two aspects: the FCL type and installation location. Implementation of the SFCL inside the DFIG wind turbine in series with the rotor side converter (RSC) leads to the rotor current reduction, DC link voltage alleviation and consequently, LVRT enhancement. Analysis and simulation results are presented to validate the effectiveness of proposed approach during symmetrical and asymmetrical fault conditions. They show that by using the proposed method, LVRT capability of DFIG wind turbines is significantly improved.