This paper describes the development status of fault-locating technology of single-phase grounding failure in small current grounding system and accordingly proposed a new fault location technique. It firstly put forward and implemented the new technologies of automatic fault isolation and non-fault line recovery using of RG-WLJ and voltage-time type circuit recloser twice. In the case of fault section isolation, it is able to determine the accurate position of ground fault point by applying the AC injection method. The paper also gave the prominence on how to fix the length of sections in order to achieve a better positioning effect. Meantime, it also introduced the method of on-line single-phase ground fault section location combining with matrix algorithm on the basis of the measurement information of FTU, and focused on analyzing in both cases of neutral non-grounding system and arc suppression coil neutral grounding system. Field experimental data fully verified the correctness and feasibility of positioning technology issued. The actual operation obtained excellent results also.
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