The current resonance equivalent circuit is used to analyze the frequent overheating fault of the cable terminal of the distribution network automation switch cabinet. The main influencing factors of overheating fault are analyzed, and the fault distribution characteristics under different climatic conditions are found. It is concluded that the discharge on the surface of semi-insulating equipment with serious insulation defects is one of the main resonant excitation sources. Based on the gas discharge theory, the relationship between the overheating fault of the terminal head and the ambient temperature and humidity is analyzed. On the basis of the resonant equivalent circuit, the governance scheme is proposed by means of destroying the resonant conditions, and the low-cost methods that can be implemented under the current operating conditions of the power grid are selected, including eliminating the partial discharge source and installing the post-insertion arrester. Compared with the fault data before treatment, it shows the accuracy of the fault analysis method and the effectiveness of the treatment measures.