地下车站顶板上方设置人工接地网的合理性研究

为了研究在地下车站结构顶板上方设置人工接地网时的电气参数合理性，采用 CDEGS 软件建立地下车站的接地网模型，对比接地网在车站结构底板下方和车站结构顶板上方的工频接地电阻值区别，并由此展开车站结构顶板上方的土壤电阻率、结构顶板上方覆土土壤厚度和接地网网格尺寸、导体直径的细化研究，结果表明：车站结构顶板上方的土壤电阻率和土壤厚度对接地电阻值起重要作用，接地网的网格尺寸和导体直径对电阻值的影响甚微，最后对接地网上方地表的接触电压和跨步电压等安全性指标进行研究。结果表明：当发生严重的短路接地故障时，在车站结构顶板上方设置接地网并不会引起地表上方的接触电压、跨步电压超标，具有较高的安全系数，证明在地下车站结构顶板上方设置人工接地网的电气参数是符合相关要求的。

The Rationality of Electrical Parameters of Artificial Grounding Grid above the Roof of Underground Station Structure

To study the rationality of electrical parameters when setting an artificial grounding grid above the top plate of an underground station structure, the grounding grid model of the underground station is established by using the CDEGS software. The power frequency grounding resistance values of the grounding grid below the bottom plate and above the top plate of the station structure are compared, and the soil resistivity above the top plate of the station structure is increased. The results show that the soil resistivity and soil thickness above the station structure roof have a considerable impact on the grounding resistance, and the grid size and conductor diameter of the grounding grid have limited effect on the resistance. Finally, safety indexes such as the contact voltage and step voltage on the square surface of the grounding grid are studied. The results show that when a severe short-circuit grounding fault occurs, setting the grounding grid above the top plate of the station structure will not cause the contact voltage and step voltage above the surface to exceed the standard and provide a high safety factor. The electrical parameters for setting an artificial grounding grid above the roof of an underground station structure are proven to meet the relevant requirements. The research results have significance in engineering practices and applications.