Ground fault location self-diagnosis in high resistance grounding drive systems

In industrial plants with High Resistance Grounding (HRG) configuration, one of the most difficult problems is to accurately detect and locate a ground fault in Adjustable Speed Drive (ASD) systems. This is because: (1) HRG ground fault current (1–10A) cannot reliably trip the over current protection function in drives; (2) In modern industrial plants, the existing methods are hard to detect and locate low voltage/low frequency ground faults; (3) With the existing methods, the fault location will be manually checked one by one using an ammeter. This paper will present a HRG ground fault self-diagnosis method for multi-ASD systems. The proposed method can solve the issues mentioned above: (1) Reliable HRG ground fault detection with wide motor speed range; (2) The HRG ground fault can be easily identified in multi-ASD systems; (3) The identification process is performed by the proposed self-diagnosis method, no trained technician is required during the identification process.