Asymmetric fault ride through capability enhancement of DFIG based variable speed wind generator by DC resistive fault current limiter

Doubly fed induction generator (DFIG) based variable speed wind generator is vulnerable to any sort of grid fault, as the stator of the DFIG is directly connected to the grid. Likewise the symmetrical faults, the asymmetrical faults also may cause the DFIG face high mechanical stress which may lead to mechanical damage. Therefore, it is very important to investigate the fault ride through (FRT) capability of the DFIG system during the asymmetrical fault situations. In this work, in order to enhance the FRT capability of the DFIG based wind generation system, a DC resistive superconducting fault current limiter (SFCL) is proposed. The performance of the DC resistive SFCL is compared to that of the bridge type fault current limiter (BFCL). Simulations are accomplished by using the Matlab/Simulink software. Simulation results clearly indicate that the proposed DC resistive SFCL improves the FRT ability of the DFIG based variable speed wind generator system during any type of asymmetrical faults in the power network. Also, the performance of the proposed method is better than that of the BFCL.