Corona effect influence on the lightning performance of overhead distribution lines

Overhead distribution lines can be seriously damaged from lightning events because both direct and indirect events can cause flashovers along the line. The lightning performance of such power lines is usually computed neglecting the effect of corona discharge along the conductors: in particular, the corona discharge determined by the indirect lightning event is taken into account only by few researchers because it can have meaningful impacts only in few cases. However, when we deal with overhead distribution lines with high Critical Flashover value (CFO) and small diameters, the corona discharge caused by indirect events has to be taken into account. This paper shows the effects of corona discharge in the lightning performance computation of overhead distribution lines. The analysis will involve different configurations in terms of line diameter and air conditions, focusing on the negative effect of corona discharge in the number of dangerous events that determine line flashovers.