The studies of the line-lightning performance of unshielded distribution lines

As overhead distribution lines and their associated equipments are most prone to insulation failure due to lightning and very much affected in terms of reliability, a study was intended to determine the line lightning performance and to analyze available mitigation options focusing on medium voltage overhead distribution line. This paper describes the simulation studies in determining the lightning performance of the chosen line using commercially available software. A Monte Carlo statistical method is applied for the simulation of lightning activity, while a three-dimensional Electro-geometric model is adopted for the determination of stroke termination. Shielding from the nearby objects is also taken into account. Linear and non-linear tower footing resistance representation, counterpoises, leader propagation flashover model are among standard features used in the simulations. Simulations are carried out to study the effects of critical flashover voltage, tower footing resistance and ground flash density on the line lightning performance. In addition, several mitigation steps to improve the lightning performance are also recommended.