Improving fault ride-through capability of DFIG based wind generators by using bridge-type superconducting fault current limiter

This paper proposes series connection of a diode bridge-type superconducting fault current limiter (SFCL) with rotor side converter (RSC) of a double fed induction generator (DFIG) based wind turbine. The proposed SFCL improves the fault ride through (FRT) capability of DFIG and prevents the RSC from damaging fault currents. Because of using superconductor DC coil, there is not any power loss during fault or normal operation of system. The proposed SFCL does not have any considerable affect in wind turbine's operation during normal condition. It is not necessary to use any measurement and control systems, too. The SFCL returns to its normal operation after fault clearing in a very short time without any switching device. The modeling of proposed SFCL is presented based on analytical analysis. Simulation of a 2 MW 690 V DFIG with and without using the proposed SFCL is carried out by PSCAD/EMTDC software. The results show the excellent operation of proposed SFCL in improving the FRT of DFIG based wind turbine.