The single phase autoreclosure is often used to improve the reliability and stability of power grid in EHV transmission lines. The connection of shunt reactor and neutral reactor is normally used to extinguish arc and to ensure success of autoreclosure. Calculation and analysis results show that the neutral reactor can maintain a low voltage at the fault location that makes arc easily extinguishing， but make it difficult to assess the level of insulation that makes reclosing within the fault line. To avoid failure of reclosure， a breaker between the neutral point and grounding point can be used. The breaker can be closed before reclosure， then the voltage of the fault line can be used to assess the insulation level of this line.