Study on Fault Analysis and Preventive Measures of Single-phase Grounding in low Current Grounding of Distribution System

The neutral point of medium voltage distribution system generally adopts the method of low current grounding to ensure the power supply reliability. This paper makes a theoretical analysis of the single-phase grounding fault of the distribution system with ungrounded neutral and ungrounded via arc suppression coil, and makes a detailed simulation analysis of the single-phase grounding fault in the distribution network system of a 35kV substation with ungrounded neutral and four 10kV outgoing lines. The variation of fault point current, three-phase voltage and current, and zero sequence voltage current during the single-phase grounding of 10kV outgoing line and the grounding via different transition resistances are obtained quantitatively. The preventive measures to reduce the occurrence frequency of such faults are given. The conclusion of this paper is of certain reference value to relevant workers in power industry.