AC Ground Fault Location for DC-AC systems based on a Grounding Resistor Voltage Analysis

The use of power converters is crucial in electric drives. However, the fault location is difficult to carry out. In this paper a new location method for ground faults in the AC side of a DC-AC converters is presented. This method is based on a grounding resistor voltage waveform analysis. This resistor is installed between the midpoint of the DC bus of the power converter and ground. Then, a histogram with the measured instant values are built. Two characteristic voltage values are calculated: the value with more repetitions and a value with more amplitude. With them, the calculation of a global fault coefficient is done and the location of the fault is determined. To corroborate this method, numerous simulations have been carried out obtaining positive results.