Diffusion Model of DC Dynamic Stray Current in Layered Soil
Liu Wei1, Yin Yichen1, Pan Weiguo2, Yang Long1, Zhang Hao1
1. School of Electric Engineering Southwest Jiaotong University Chengdu 610031 China; 2. Beijing National Railway Communication Signal Research and Design Institute Group Co. Ltd Beijing 100071 China
Abstract：In order to study the interference range and influence degree of the stray current of the DC traction power supply system, the distributed circuit of the return system was equivalent to a centralized circuit. The node voltage method is used to calculate the system power flow. Accordingly, a dynamic distribution model of the stray current over time was established, and the diffusion model of dynamic stray current in layered media was established by the superposition principle. The Prony method was used to solve the model. Compared with the simulation results of CDEGS software, the ground potential calculation error was within 8.66%. A domestic subway line adopts 6B grouping, the maximum speed is 80km/h, the departure interval is 2min, the concrete resistivity is 0.503Ω·km, and the soil resistivity is 38.9Ω·m. When the distance between the buried metal structure and the subway line is 50m, the rail transition resistance value is increased to more than 40Ω·km, or when the rail transition resistance value is 5.31Ω·km, the distance between the buried metal structure and the subway line is increased to more than 0.25km, and the ground potential gradient along the line is less than 2.5mV/m, which means shortening the power supply distance can reduce stray current interference.
刘炜, 尹乙臣, 潘卫国, 杨龙, 张浩. 直流动态杂散电流在分层介质中的扩散模型[J]. 电工技术学报, 2021, 36(23): 4864-4873.
Liu Wei, Yin Yichen, Pan Weiguo, Yang Long, Zhang Hao. Diffusion Model of DC Dynamic Stray Current in Layered Soil. Transactions of China Electrotechnical Society, 2021, 36(23): 4864-4873.
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2021, Vol. 36 
