Study of the effect of multi-scale soil electrical properties on the high-frequency response of substation grounding systems

• A systematic comparison of grounding system behavior under different soil stratification models is conducted using high-frequency fault current condition. • Three representative soil configurations are constructed based on field resistivity data and simulated via the CDEGS platform. • The study reveals that soil structure significantly alters key grounding parameters, with impedance, contact voltage, and scalar potential. • The findings offer practical guidance for substation grounding design, emphasizing the necessity of accurate soil modeling in modern high-frequency fault scenarios. The security and stability of the grounding system is critical for the reliable operation of new power systems, and the multi-scale distribution characteristics of soil electrical properties can significantly affect its high-frequency fault response performance. In this paper, typical soil models including uniform, horizontally stratified and vertically stratified are constructed based on the resistivity data measured in the actual project, and the electromagnetic be haviour of the grounding network in the 50 Hz-50 kHz band under different models is simulated and analysed by using the CDEGS system. The results show that soil structure significantly affects the key metrics of grounding impedance, contact voltage and scalar potential, with maximum differences of more than 70%, 90% and 50%. Among them, the vertical hierarchical model exhibits nonlinear jumps and multi-peak characteristics, while the horizontal hierarchical model achieves a better balance between stability and accuracy. The study reveals the dominant role of soil layering structure in the high-frequency response of the grounding system, and suggests more engineering-applicable modelling. This study provides a quantitative basis for assessing the performance of grounding networks under high-frequency conditions, and provides theoretical support for the design and modification of new power system grounding. theoretical support for the design and modification of new power system grounding.