Modified switch type fault current limiter for low-voltage ride-through enhancement and reactive power support of DFIG-WT under grid faults

摘要

The sudden voltage drop may upsurge the current level and trigger the self-protective system to disconnect the wind turbines that are detrimental for grid constancy. A novel structure of a modified switch type fault current limiter (M-STFCL) is proposed that protects the doubly-fed induction generator wind turbine (DFIG-WT) during the symmetrical and asymmetrical grid faults. The M-STFCL is cost-effective and requires little maintenance during operation. The proposed system maintains the rotor current and DC-link voltage below the maximum acceptable limits, thus, fortify the back-back converters. The M-STFCL is tested with both the sliding-mode control (SMC) and proportional-integral (PI) controller and their results are compared. From the simulation results, it is obvious that SMC has edged over the PI controller and demonstrated superior control over the critical parameters. The performance of M-STFCL is also compared with the conventional switch type fault current limiter and the analytical results clearly validate the significance of the proposed system.