Study on the Frequency Characteristics of Grounding Resistance in Non-uniform Soil Regions

The grounding system is an important measure to maintain reliable operation of power systems and ensure the safe of equipment and human body. Grounding resistance is an important parameter to judge whether the grounding system meets the requirements. This paper aims to study the frequency characteristics of grounding resistance in non-uniform soil regions. By using the software CDEGS, a three-layered soil model was made, and the simulations of the influence of upper soil resistivity, upper soil layer thickness, middle soil resistivity, middle soil thickness and lower soil resistivity on grounding resistance based on horizontal three-layered soil structure were carried out. And the frequency characteristics of grounding resistance under several situations were studied. It is concluded that frequency has a greater effect on grounding resistance in the areas with higher resistivity and smaller thickness of upper soil.