A new single phase fault location method of noneffectively grounded networks for DA systems

The paper presents a new small current grounding fault location method applicable to distribution automation systems (DASs) using fault transient currents. The faulty section is identified by comparing the degree of similarity of transient currents of feeder terminal units (FTUs) (including faulty line selection device) at adjacent switches. If both transient currents are highly similar, then the section is regarded as the sound section, otherwise as the faulty section. The paper also analyzes the adaptability of the transient localization algorithm on DAS, as well as other key technologies such as time synchronization for FTUs, software and hardware processing ability, etc. The prototype system was installed in a typical distribution system in Xiamen Power Supply Bureau, State Grid Company of China. Dozens of grounding fault transients were captured with correct faulty line identification and faulty section localization. The method is reliable, free from the influence of arc suppression coil and easy to be implemented. It makes DASs function more complete, and helps to improve its overall performances.