Study on the Simulation of the EMU Body Operating Main Breaker Overvoltage and High-Voltage Side Suppression Method Based on the 3D Structure

Current circuit simulation research on EMU (Electric Multiple Unit) overvoltage has focused on overvoltage amplitude distribution and the oscillation frequency of the operating main circuit breaker overvoltage. However, when studying the suppression method, the overvoltage amplitude and frequency characteristics must be considered simultaneously, and few studies have reported on the overvoltage frequency distribution. In this paper, a new simulation model of train-operational main breaker overvoltage based on the 3D structure of the EMU body was proposed, which provided guidance for the study of overvoltage suppression in operational main circuit breakers. This model simulated the transient overvoltage characteristics and distribution of the vehicle body when the train operated the main circuit breaker. The simulated results showed that the first vehicle had the highest operating overvoltage amplitude, and the fourth vehicle had the lowest. The overvoltage amplitudes of vehicles 1–4 were all above 1 kV, and the main overvoltage oscillation frequencies of each vehicle were at 0.70 MHz and 1.30 MHz. The accuracy of the distribution characteristics and spectral characteristics of the operating main breaker overvoltage was verified by static tests on trains, and the simulation was considered to be in agreement with the test. Aiming at the problem that there was no universal suppression method for the operating main breaker overvoltage, a general suppression method for the overvoltage on the high-voltage side of the EMU was studied, and an overvoltage suppression device based on a grounding inductor was proposed. The inductance parameter requirements of the suppressor were theoretically analyzed, and the validity of the design of the inductance suppressor was experimentally verified.