Analysis on the impact characteristics of grounding device considering spark effect

Under the effect of lightning current which is with large amplitude, the grounding device and surrounding soil will have spark effect, which makes device show complex impact characteristics and affect the current dissipation process. In this paper, using the parallel plate device, the quantitative relationship between the resistivity of sandy and brown yellow soil and the field strength is obtained, which is expressed as a piecewise function. Considering this relationship, a finite element model of impact dissipation for grounding device is established. A test platform is built, and the impact test data of different topological forms is used to compare with the results of the model, which can verify that the model can effectively analyse the spark effect of the grounding body. After carrying out simulation for the grounding body of different topological forms, this paper analyses the impact dissipation characteristics of the horizontal grounding body and the grounding body with short conductors.