The Influence Mechanism Of High-Speed EMU Traction Return Current For Operation Conditions

Train grounding system is a very important part of the traction power supply system. A good body reflux is the key to high-speed trains under security and stability operations. With the continuous development of China’s high-speed railway, high-speed EMU grounding reflux problem has gradually become the core of the train grounding system with most attention. The operating environment of high-speed EMU is very complex. And EMU grounding system is under a dynamic changing process. Compared with ordinary trains grounding system, high-speed train’s speed increased dramatically. Because of the traction load current increases, the short circuit current increases, high traffic density and other factors, high-speed EMU earth return system is facing many challenges. EMU runs under different conditions, the return current variation of traction power supply system is different. EMU current distribution between the various grounding also has a great difference. On one hand, due to the traction current increasing, it makes vehicle control and communications systems easy to electromagnetic interference. It also causes the bearing electrolytic corrosion. On the other hand, EMU traction return current uneven distribution can cause abnormal wearing of grounding brushes. This increases the operational difficulty of maintaining high-speed EMU. Therefore, study the influence mechanism of high-speed EMU operation conditions for traction return current is meaningful. Research the influence mechanism for the distribution of EMU grounding return current in different operating conditions, explore measures to make rational allocation of current in a changing operating environment, optimize and improve EMU grounding system thus improve the operational reliability and service performance of high-speed EMU.Firstly, this article points to the high-speed EMU of high-speed railway on the actual operation for the study. Use PSPICE simulation software to build EMU traction return current system equivalent circuit model which including EMU, catenary and traction substations. Based on the test measured data, the EMU return current distribution of working grounding and protective grounding under normal operating conditions are analyzed.For high-speed EMU passing through the insulating section, and passing suction line two different operating conditions established analysis model, and simulated vehicle body reflux distribution curves over those two conditions. Study on the train reflux current variation in two conditions, each ground current distribution characteristics and changes duration, and comparative analysis the measured data to figure out the influence mechanism of special conditions for train’s return current.Finally, the distribution of EMU return current in different operating conditions has been analyzed. And research the key factors affecting return current, combine simulation data with test measurement data to verify the theoretical analysis. Discuss the impact of EMU grounding structure in return current distribution. Optimizations has been put forward to uniform grounding current distribution and lower peak current by reducing grounding points and adding grounding resistance. The work has been done in this paper providing a theoretical basis for the EMU system optimization reflux.