Abstract: Hanging the grounding wire is a key link in the power outage maintenance in the overhead contact system,providing effective protection for power maintenance. To further strengthen the safety risk control of power maintenance operations and address the issue that the existing detection devices are unable to detect whether the grounding wire is reliably grounded during power outage maintenance operations in the overhead contact system,a method is proposed to use residual charges and induced voltage on the contact wire to detect whether the grounding wire is reliably grounded. Firstly,equivalent circuit models are established for single line and double line sections when hanging grounding wires for power outage maintenance. The residual charge of the contact wire and the induced electricity from the "V" shaped skylight maintenance are used as equivalent excitation sources to theoretically calculate the grounding wire current;Secondly,a grounding status detection device based on this method is developed to determine whether the grounding wire is well grounded; Finally, experiments are conducted using the constructed current generation platform, and the status information of the grounding wire is remotely monitored in the background through LoRa self-organizing network communication with the original system. The experimental results have verified the feasibility of the proposed method.