A full-wave analysis of lightning-induced voltages on distribution lines considering the conductive coupling between the lightning channel and the grounding system

Two approaches for the numerical solution of the full-wave Maxwell´s equations, based upon the finite element method and the method of moments, are here used for the computation of lightning induced voltages on overhead distribution power lines. The methods are well suited to consider both induced and conductive coupling mechanisms between the lightning return stroke channel, the overhead line conductors and the grounding system of the line. It is noted that this last effect is traditionally disregarded in the computation of lightning induced overvoltages. It is shown that the conductive coupling might result in the reduction of the lightning overvoltages induced on overhead lines. This finding justifies the inclusion of the conductive coupling in the available approximate formulae used for the calculation of lightning induced overvoltages.