Impacts of grounding configurations on responses of ground protective relays for DFIG-based WECSs-Part II: High-impedance ground faults

Ground faults are one of the major disruptions of the safety, stability, and economic operation of doubly fed induction generator (DFIGs)-based wind energy conversion systems (WECSs). On one hand, the minimization of possible damages caused by ground faults can be achieved by the accurate and reliable detection and identification of these faults. On the other hand, the fast response to ground faults is highly influenced by the grounding configuration, especially in cases of high impedance ground faults. This paper investigates the influences of grounding configurations on the responses of ground protective devices used in DFIGs-based WECSs when experiencing high impedance ground faults. The open (no-grounding), high-resistance, low-resistance, and solid grounding configurations are investigated in this paper. The influences of the grounding configurations are observed through the ability of protective devices to detect, identify, and respond to high impedance ground faults occurring in DFIG-WECSs. Test results show that the responses of ground protective devices, used in DFIG-based WECSs, can be sensitive to the grounding configuration, as well as the fault impedance.