Adaptive Auto-Reclosing and Active Fault Detection of Lines Emanating From Wind Farms in Microgrids

Most line faults in microgrids are temporary and are cleared shortly after the fault inception using an auto-reclosing (AR) scheme. However, there are limitations to the AR activation in generation-ended lines of microgrids because reclosing on a permanent fault may cause severe electrical and mechanical stress to generators and turbines. On the other hand, reducing the generator outage time caused by temporary faults is important, especially for distributed generators (DGs), because they significantly affect voltage control and grid stability. In this article, a three-phase adaptive AR scheme for wind farms equipped with doubly-fed induction generators (DFIGs) is presented. The dead time of the proposed method is adaptive and can be set at a minimum value considering the fault condition. The DC-link capacitor of the DFIG converters is used to generate diagnostic pulses to ensure fault clearance. This AR scheme helps to reduce the power generation outage time. Also, it prevents reclosing during permanent faults using active fault detection. Simulations and experimental tests are conducted to evaluate the efficiency of the proposed scheme.