Calculation of the Distribution of the AC Current in the Earth by the Finite Element Method
Xishan Wen · Gao dianya jishu · 2006
When the electric current infloods from the grounding pole to the earth,the distribution of the electric current in the earth makes important influences to the potential of the grounding poles and the surface current density.In this paper,laws of the current distribution in the earth under Alternating Current are investigated.As the old near model has many insufficiencies,whose assumed condition is that the current is equal at the ground surface and at the same radius,so that the analytic solution can be carried out,the results from this conventional method could only reflect the current change with the depth in the earth,but not enough to reflect the current distribution at the ground surface.In this paper,the current in the earth is recalculated by finite element method.The finite element method has many advantages,the original model could be solved with no change,and the current in multiplex stratified soil or in special landform can be calculated as well.By analyzing the results we could find the laws,including the axial current distribution and the transverse current distribution,which are similar.Then the frequency is changed to analyze its influence to the current distribution.In conclusion,compare with the old near model,the results prove that the finite element calculating method is convenient,and its data is precise and visualized.The results also indicate that the current concentrates towards the transmission line under AC power frequency.The current in the ground surface raises fast and the current in the deep earth decays fast with the increase of the frequency.