A Semi-Analytical Approach to Calculate Lightning EM Fields Considering Channel Tortuosity

The most common lightning channel model consists in a vertical thin-wire radiator, even though it is known that lightning path is affected by tortuosity. This physical characteristic of lightning has remarkable effects on the generated electromagnetic fields and, consequently, on the voltage induced on transmission and distribution lines, which may lead to insulator flashover. This contribution presents a novel semi-analytical approach for the calculation of lightning electromagnetic fields considering channel tortuosity with an arbitrary current source. Results are validated against a benchmark numerical method showing fine accuracy and an improvement in computational efficiency. Indeed, the proposed approach avoids the time-consuming convolution integral on the source current which, on the contrary, is required by the benchmark numerical method.