Identifying ground fault location in High Resistance Grounded systems for Adjustable Speed Drive at low speed

One of the more difficult problems to solve in industrial plant is to locate and eliminate a ground fault in High Resistance Ground (HRG) system. This is because ground fault conditions in these systems do not draw enough current to reliably trigger fault current sensors in the drive. For an Adjustable Speed Drive (ASD) drive operated in a HRG system, a load side ground fault generates very low fundamental grounded current (<;1A) to the system at low speed. This adds the complexity for ground fault detections. This paper developed an approach to identify the ground fault for ASD drive operating under this condition. The voltage-second of the voltage are recorded and their peak value is used to predict ground fault. Analysis, simulation and experimental result are all presented in this paper to show the effectiveness of the proposed method.