Integrated Protection of DFIG-Based Wind Turbine With a Resistive-Type SFCL Under Symmetrical and Asymmetrical Faults

This paper presents a novel protection scheme for in-grid doubly fed induction generator (DFIG) by using a resistive-type superconducting fault current limiter (SFCL) connected in a series with the DFIG rotor winding. The basic principle, prototype design, and system modeling are presented to integrate the DFIG and SFCL modules into one electrical-superconducting-mixed device. The comprehensive evaluation of the proposed scheme and the comparative study with the conventional crowbar-based scheme are carried out. The results obtained show that the proposed scheme is favored to limit the peak values of the fault rotor current, dc-link voltage, and electromagnetic torque oscillations, and thus to protect the rotor-side converter, dc-link capacitor, and mechanical parts under symmetrical and asymmetrical faults.