Effect of Horizontally Layered Soil Structure on Induced Lightning Overvoltage

Studying the effect of horizontally layered soil structure on induced lightning overvoltage can provide a reference for lightning protection design of distribution lines. By establishing a 2-D finite-difference time-domain (2-D FDTD) algorithm model, combined with the improved Agrawal coupling model, the induced lightning overvoltage of distribution lines is calculated. The algorithm is used to study the variation of induced lightning overvoltage in distribution lines under different levels of layered soil structure. The results show that: when the conductivity of the upper layer is lower than that of the lower layer, the peak value of the induced lightning overvoltage increases gradually with the increase of the thickness of the upper layer of soil. When the conductivity of the upper layer of soil is greater than that of the lower layer, and when the thickness of the upper layer of soil is greater than 10 m, the amplitude of induced lightning overvoltage is almost determined by the upper layer of soil. The research conclusions can provide a certain reference for the lightning protection design of the line.