Electromagnetic Coupling of Lightning to Power Lines: Transmission-Line Approximation versus Full-Wave Solution

The problem of accurate prediction of lightning-induced overvoltages on power lines still attracts considerable attention. A variety of approaches of different levels of sophistication have been proposed. In particular, transmission-line (TL) approximation is widely used for describing electromagnetic coupling of lightning with power lines. In this paper, validity of this approach for lossless lines is demonstrated by analytically demonstrating that, under the assumptions that are typically justified for practical power distribution lines, the TL approximation and the more rigorous full-wave analysis lead to identical results.