Abstract. Reclosing technology is widely used in EHV transmission system of China. In Shanxi 220kV power grid, the reclosing delay time is commonly set to 0.5s, while there used to be several reclosing failures in recent years. This paper focuses on this problem, the transmission system as well as transmission lines are modeled, and factors that may influence secondary arc are investigated. In addition, suggestions on auto-reclosing time setting for Shanxi 220kV power grid are proposed.