Improvement of Fault Ride Through Capability of DFIG-based Wind Turbine Systems Using Superconducting Fault Current Limiter

Due to high penetration of renewable energy in grid, the latest grid codes require that Wind Turbines (WT) stay connected to the grid and provide reactive power support for grid voltage recovery. This paper proposes a technique to improve Fault Ride Through (FRT) capability of a Doubly Fed Induction Generator (DFIG) bases WT system. The proposed technique is implemented through a resistive type Superconducting Fault Current Limiter (SFCL). The SFCL is introduced in two locations in DFIG circuit; firstly in Rotor Side Converter (RSC) and secondly in Grid Side Converter (GSC) to decrease rotor and stator currents respectively. The scheme is tested on a 1.5 MW DFIG based grid-connected Wind Turbine system. Simulation results show that the SFCL at proposed locations limits rotor and stator currents, electromagnetic torque oscillations, DC link over voltage and also help in grid voltage recovery. The scheme efficiently improves the FRT capability of the WT system and fulfills the grid code requirements.