Distribution of stray current based on 3-Dimensional earth model

An accurate electric model of the earth is important for many applications related to electric traction and distribution systems like the stray current. As the DC electrified traction system is the potential source of the stray current, the operation of traction vehicles such as trains and trams makes the emergence of stray currents in the area of rails and under the rails. These leakage currents can adversely affect pipelines or cable lines near the rail [7][11]. There exist numerous models which have been modeled this phenomena [2][4][11], all models are based on one Dimensional earth structure, actually the nature of the earth underneath of the railways could not be represented as a homogeneous medium. The characteristics of the soil vary depending on the location and locally with depth, and a homogeneous earth model might be inadequate. [1] shows that even the multi-layered earth models are not reliable to be the base of the calculation of several applications related to the earth and grounding systems and it is required an accurate earth model which can give a better overview of whole structure of the underneath ground. In this work after a general presentation of the existing and proposed earth model, it is presented a comparison between the calculation of the stray current propagation based on one and 3-Dimensional earth model.