A faulty section location method for distribution grid based on grounding fault transfer device

Abstract

In the distribution grids, grounding fault transfer devices have been widely used to suppress the transient arc grounding fault. Based on the grounding fault transfer device, a high sensitivity faulty section location method is proposed in this paper. When an arc grounding fault occurs, the fault phase bus is earthed by the grounding fault transfer device, which can simultaneously realize arc suppression and faulty section location. There are two grounding transient processes in this method, including fault grounding and active grounding of the faulty phase bus. During the aforementioned processes, the similarity degree of the zero mode current on both directions of the faulty section varies from low to high, whereas there is almost no change in the healthy section. The ratio of S transform energy relative entropy is used to represent the level of change of the similarity degree on both directions of each section. The section with the maximal entropy ratio is determined as the faulty section. The proposed method does not need to set the threshold and presents higher sensitivity for an arc fault. Simulation proves the sensitivity and accuracy of the proposed method.