The discovery of the fault location in NIGS

A new method is discovered for calculating the fault distance of the overhead line of the Neutral Indirect Grounded System (NIGS) in power distribution networks, in which the single phase to ground fault point or distance is difficult to detect, because the zero sequence current is in lower value. It is found that the information of the fault distance is kept in the zero sequence voltage vector which may be measured at the tail terminal of the questioned line by digging the data. Then an algorithm to calculate the fault location on the overhead lines is proposed by considering that the zero sequence voltage vector at the tail terminal. The value of the zero sequence voltage is determined by the fault location, and the phase angle also contains the distance traveled by the load current to the fault point. The system analysis for parameters is conducted for the NIGS by considering line is actual and by the two terminals´ parameters.