Research On Characteristics Of Overvoltage And Electromagnetic Field On High-Speed Trains

High-speed railway, as the integration of multiple cutting edged techniques in contemporary era, has gradually developed into a major carrier of our country for its strong transport ability, high speed, and environment protection. Electric Motor train Unit (EMU) must be ensured performing safely and reliable to improve the quality of service. Because of our high speed railway across the vast territory, different environment, climate difference is big, high speed EMU lightning occurs short circuit, the roof insulator breakdown, a high voltage box abnormal short circuit occurs, the one hand easy to cause the body to produce over voltage, over voltage is easy to cause the vehicle body control system, communication system, logic confusion and even cause electromagnetic interference damage to components, and the vehicle body over-voltage leads to body potential uplift, easy to cause the bogie bearing breakdown, a lot of traction current through the bearing, bearing caused by electric erosion, and lead to abnormal wear of grounding resistance; on the other hand, the vehicle body is created around the transient electromagnetic field, transient electromagnetic field is easy to induce overvoltage with the vehicle electrical equipment and passengers, the threat to its security, serious or even affect the safety of train running. Therefore, accurate analysis the body over voltage distribution of special conditions, for optimization and improvement, thereby inhibiting body over voltage is too high and the guarantee of the normal discharge of overvoltage body ground; not only give the in-depth research of vehicle electromagnetic distribution law lay the foundation through calculating the surface of the body and the internal electromagnetic field, but also electromagnetic protection measures effectively to improve the reliability of the car body.With the high speed EMU entities as objects, set up a equivalent circuit model with high-speed EMU--contact network--substation, body overvoltage mechanism with lightning, breakdown of the insulator, high pressure tank.based on the theory of electromagnetic field were established finite element calculation model of the actual vehicle, study on the distribution regularity of body electromagnetic field under normal conditions.With Lightning over voltage, breakdown vehicle roof insulator body over voltage, high voltage box short body over-voltage mechanism, constructed equivalent circuit structure with PSpice, analysed the distribution law of body over voltage, give out its magnitude and duration. Study on the effect lightning overvoltage for increasing grounding resistance of the body, and the grounding resistance of vehicle impact effects of over voltage amplitude, proposed ground resistor values from 0.1Ω.Based on the theory of electromagnetic field to construct finite element body 3D electromagnetic short-circuit calculation model with lightning, high voltage box. research on body distribution law of electromagnetic field on body cross section, axial plane, longitudinal section,when lightning current is 6kA. and when the high voltage box short circuit is 4kA, the electromagnetic field distribution of the vehicle body, proved the distribution areas of highest field strengths; with testing analysis of car body electromagnetic field, proved the test results accord with the simulation results, and further clarify the distribution of electromagnetic field in the body.