Research of detection method for IT system ground fault of EMUs

In order to judge whether the single-phase grounding fault occurs in the neutral point ungrounded power supply system (IT system) of the electric multiple units (EMU), we calculated the formula of zero-sequence voltage with three-phase load and designed the test circuit to get the grounding situation in IT system. The experimental model was simulated in MATLAB, which proved that the formula was correct. We built the actual experimental platform to test single-phase direct grounding, single-phase grounding through resistance and two-phase grounding through resistance. In the end, we obtained the range of the zero-sequence voltage and the law of the zero-sequence voltage with the three-phase load.