Intermittent arc grounding can produce re-distribution process of multiple energy between the faulty pahse and healthy phase

which induces overvoltage on the healthy phase and causes great harm to the insulation of medium and low voltage distribution grid. Therefore

it is necessary to strengthen online monitoring and analysis of power system and to adopt appropriate and positive measures. In this paper

the generation mechanism and its serious consequences of single-phase arc grounding fault in medium and low voltage distribution grid of neutral ungrounding system is studied. The typical single-phase ground arcmodel is set up and its simulation is verified. On that basis

the suitable single-phase arc grounding model is selected and further simulation and verification on the generation process of arc grounding fault is made firstly by the use of the simulation device ADPSS of large power system. It is sho-wn by the simulation result that the arc grounding fault model of neutral point unearthed system which is set up based on the ADPSS simulation platform in this paper and ahs higher engineering application value.