10 kV配电网断线坠地故障地表电势分布及安全距离研究

Study on Surface Potential Distribution and Safety Distance of Disconnected Grounding Fault in 10 kV Distribution Network

研究配网线路断线坠地故障的地表电势分布,可为线路巡检,安全防护工作提供理论支撑。针对城市电网土地特点,构建了3层土壤模型,采用点电流源格林函数,分析了在干土地、湿土地、干混凝土地、湿混凝土地等不同工况下的地表电势分布,并通过现场试验验证了上述方法的正确性,最后结合工频电流对人体的威胁程度,划定了不同故障场景下的危险/安全距离。

Studying the surface potential distribution of disconnected grounding fault of distribution network line can provide theoretical support for line inspection and safety protection work.In view of the characteristics of the ground of urban power grids,a three-layer soil model is constructed.The point current source Green’s function is used to analyze the surface potential distribution under such different working conditions as dry land,wet land,dry cement land and wet cement land.The correctness of the method mentioned above is verified by site test.Finally,the criteria for the danger/safe distance in different fault scenarios is defined in combination with the threat of power frequency current to the human body.