Research on Soil Potential Distribution Caused by Metro Stray Current

The harm of stray current in urban rail transit is becoming increasingly serious, and the corrosion of buried metal pipelines and DC bias of grounding transformers caused by it have attracted attention from various aspects. Soil potential distribution is a common entry point for metal corrosion and DC bias problems. Therefore, from the perspective of urban soil potential distribution, this article constructed a four-layer ground grid return current model and deduces the voltage distribution of steel rails, and constructed a urban soil potential distribution model. Analyzed the interference range and degree of stray current during subway operation. The results indicated that an increase in the DC resistance of the rail will significantly increase the soil potential, increase the range of stray current influence, and increase the risk of DC bias and rail corrosion in the substation. Increasing the rail-ground transition resistance can effectively reduce the risk of stray current hazards in nearby soil areas. The larger soil resistivity also has a certain limiting effect on the propagation of stray currents.