Micro‐element statistics and their application in the study of soil model electrical conductivity

Abstract The design of a grounding system is influenced by the soil conductivity. The cost of a ground grid in areas with different soil resistivities varies from tens to hundreds of times to achieve the same ground resistance. Existing studies have found that the electrical performance of soil changes suddenly with the change in water contents. However, it can only be assumed macroscopically that this change is caused by the connectivity of water distribution. Neither this assumption can be confirmed nor any critical conditions can be defined. This paper presents a mathematical study of soil conductivity from a microscopic point of view, known as the micro‐element statistical method. The method uses scientific statistical analysis to study the apparent conductivity of water elements in soil and is used to conclude that the apparent conductivity at the micro level is exponentially distributed. Based on the relationship between the mean of apparent conductivity distribution and water contents, the critical condition of soil resistivity mutation is defined, and the mechanism of soil resistivity change is explained. The method presented in this work can be used to study the influence of temperature, ion type concentration, solid particle type and pore structure on soil conductivity by changing the corresponding conditions and material type.