FDTD Modeling of the Earthing Conductor in the Transient Grounding Resistance Analysis

The grounding system plays an important part in the lightning protection system of power and communication systems. The finite-difference time-domain (FDTD) method is widely used in modeling complex electromagnetic interaction problems. However, it is difficult to model the earthing conductor using the standard FDTD method in the transient grounding resistance (TGR) analysis for the electrically small depth of the earthing conductors. In this letter, a new method has been proposed to model the earthing conductor by incorporating the singularities of the field variation near the conductor into the Faraday's contour path. The efficiency of the proposed model has been approved by verifying both the supposed field distribution near the earthing conductor and the TGR.