Optimal Design of Grounding System Considering the Influence of Seasonal Frozen Soil Layer

Abstract

Frozen soil leads to the change of the soil model. This would affect the safety of the grounding system. The design of the grounding system considering the seasonal frozen soil should be based on the full investigation of the actual maximum depth of the frozen soil and the actual layered soil models. The final design scheme of the grounding system should be determined synthetically from two phases-first, the grounding system is designed in the normal soil model and its safety is checked in the frozen soil model, second, it is designed in the frozen soil model and its safety is checked in the normal soil model. The influences of the frozen soils on the optimal design of grounding systems in homogeneous and double-layer soil models were systematically analyzed, and the respective design methodologies of the grounding systems were proposed. The influence of vertical electrodes on the design of the grounding system considering the seasonal frozen soil was discussed. The analyzed results state that the safety of grounding system can be sufficiently improved by vertical grounding electrodes added to the horizontal grounding grid.