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

Abstract

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