Insulation Fault Location Method for DC Distribution Systemof Autonomous-Rail Rapid Tram

Insulation fault detection and location device is necessary for DC distribution system on board of the Autonomous-Rail Rapid Tram (ART). This paper first analyzes the existing insulation detection and location methods and points out their problems. And for the fault characteristics of the DC distribution system on board of ART, the series voltage source and voltage divider circuit are added on the basis of the traditional method of combining the unbalanced bridge and the DC leakage current. The method can satisfy the demand of system detection and location and at the same time reduce the demand for voltage withstand of the location components. Simulation results verify the proposed method can accurately calculate the insulation resistance of each faulty branch under different fault conditions, including single-branch unipolar insulation fault, single-branch bipolar insulation fault, multi-branch unipolar insulation fault, and multi-branch bipolar insulation fault. The proposed method is flexible in configuration, especially suitable for DC distribution system with large monitoring range and many branch circuits.