Abstract: The small current grounding modes such as isolated neutral mode and neutral grounding via arc suppression coil mode are mainly adopted in medium voltage distribution networks in China. The single-phase arc grounding fault is the main fault form in medium voltage distribution networks. In this paper, the Mayr model is taken as an example to analyze the influence of two parameters on the voltage and current of the arc model. The equivalent sequence network diagram of the A phase-to-ground fault in the feeder of the resonant ground distribution system is used to construct the circuit. The effectiveness of the arc model was analyzed and proved in a low-voltage distribution network system. It can proved important theoretic support for the faulty feeder identification under single-phase grounding faults in the neutral non-effectively grounded system.