Description: An AC-DC electric locomotive passive circuit ground fault detection method and apparatus. The apparatus includes a main controller, voltage acquisition unit, the alarm unit, the host computer. Voltage acquisition unit between positive and negative DC bus access detection voltage divider resistors R1, R1 ', R2', R2, R1 ', R2', respectively, in parallel with an isolation amplifier, the main circuit of positive and negative ground voltage V1, V2 through After the resistor divider into isolation amplifier, and then through the main controller of A / D input port host controller, the input data as a failure of judgment. The passive detection method utilizing SCR will produce each locomotive is running with load voltage spike conduction characteristics determine the main circuit conditions; by calculating the percentage of positive and negative changes in the bus voltage to determine whether the main circuit DC side ground fault occurs; by sampling of the positive and negative bus voltage fast Fourier transform, to calculate the 50 Hz voltage component size, and set a good alarm threshold corresponding to different conditions, and determines whether there is a main circuit AC ground fault.
DOI: G01R31 / 00 (2006.01); B60L3 / 00 (2006.01)