Evaluation of lightning-originated stress on distribution class surge arresters✰

The paper focuses on evaluating the stress on distribution class surge arresters (SAs) caused by lightning strikes. It proposes a procedure for estimating the statistical distribution of energy absorbed by SAs due to both indirect and direct lightning strikes, which is a crucial step for assessing the probability of SAs failure. Two different SA representations are considered, namely, a static nonlinear resistance and a dynamic, frequency dependent model. After analyzing the overvoltage and current waveforms caused by lightning strikes and considering the effect of flashover occurrence, the paper assesses the effect of several factors on the current and energy absorption, namely the presence of a periodically grounded shield wire, of the grounding resistance value, and of the dis tance between subsequent SAs. The analysis shows that the static model can be considered accurate enough for evaluating the stress originated by direct and indirect lightning on distribution class SAs.