Lightning-induced Overvoltage of 10 kV Distribution Line Based on Electromagnetic Return -stroke Model Using FDTD

Generally, lightning-induced overvoltage is a cause of most lightning trip accidents. In this paper, 3-D FDTD numerical method is used. The full-wave analysis solution of the electromagnetic field is obtained by selecting the electromagnetic return stroke model of the lightning channel, and the lightning-induced overvoltage of the distribution line is calculated directly. The influences of both the ground conductivity and the distance between the distribution line and the lightning strike point on the propagation characteristics of lightning-induced overvoltage are analyzed. The conclusion shows that when lightning strikes the lossy (a=0.01 S/m) and ideal ground (a=oo), the changing trend of lightning-induced overvoltage at the middle point of the line is similar, but the former has a higher amplitude of lightning-induced overvoltage. The maximum value of the overvoltage presents a second-order exponential decay trend with the distance.