Abstract: Fault location of high-voltage overhead transmission lines is a hot topic of concern in power engineering. Large spans are prone to disconnection faults, which affect the safety of power grid operation. Taking the 110 kV highvoltage overhead transmission line as an example, the research analyzes the disconnection fault in the large span section, and adopts a combination of temporary disposal and permanent disposal measures to repair the line breakpoint, which can ensure the recovery of power supply and eliminate the potential late stage of the line. Security risks.