The Influence of Geological Characteristics on the Surface Potential Distribution of Metro Stray Current

Abstract

In recent years, the transformer DC bias phenomenon has often occurred in transformer transformers near subways in China. Due to the serious exceeding of the operating voltage and current, the safe operating state of the transformer and the quality of the power system supply and transmission are threatened. Analyzing the influence of DC bias on the surrounding transformer, the magnitude of the inflow current in the surrounding area can be studied, but the most direct is to study the distribution law of the surface potential in the surrounding area. In this paper, a simulation model is established based on the field geological characteristics of a certain area in Guangzhou, and the surface potential is calculated through the model, and then the correctness of the simulation model is verified by the surface potential data measured on the spot. The simulation model analyzes the influence of different soil structures on the surface potential of subway lines and groundwater systems. The results show that compared with the factor of rail burial depth and the resistivity factor of the river, the soil resistivity has a greater influence on the surface potential, and the surface potential is greater when the soil resistivity is greater.