In the power system, overheating points of high-voltage transmission lines usually occur at the connection fittings of current carrying conductors, while discharge or overheating of overhead ground wires is extremely rare. China stipulates that overhead ground wires should be installed along the entire 220kV and above transmission lines to reduce the probability of direct lightning strikes on the conductors. The grounding wire of 220kV transmission lines is usually made of galvanized steel stranded wire with a cross-sectional area of not less than 35mm2, placed above the high-voltage transmission line, and connected to the grounding of each tower with the grounding wire. Some transmission lines have overhead grounding wires that extend to the incoming line structure of the substation. The overhead ground wire is installed parallel to the 220kV transmission line, and there is induced electricity on the overhead ground wire. Although the induction frame of overhead ground wire is relatively high, the current is very small and will not cause overheating.