Response of distribution networks to direct and indirect lightning: Influence of surge arresters location, flashover occurrence and environmental shielding

The paper deals with the response of distribution networks to direct and indirect lightning. The response of the network is analyzed with the aim of inferring the mean time between failures of the connected transformers. This is accomplished taking into account the voltage at the utility frequency, the flashovers occurrence in the line insulators, the location of surge arresters, and the shielding provided by nearby buildings. Two different transformer failure criteria are assumed: a critical value and a disruptive effect model. The results make reference to multi-conductor overhead systems with two different topologies: simple straight line and a real feeder with laterals. It is shown that such a detailed lightning performance analysis is useful in order to select the most appropriate strategy for the installation of surge arresters, which may allow the achievement of the desired mean time between failures at affordable costs.