Relation of Lightning Induced Flashovers with Stroke Distance and Current Peak

Lightning current peak amplitudes and stroke locations are data provided by lightning location systems, albeit with some approximation. We argue that a minimum threshold/value of the ratio between current peak and distance of the stroke location from the line must be reached for an insulation flashover to occur. Equations and/or models providing a relation among induced voltage values, distance and current peak are available: the paper compares the results predicted by Rusck's formula and Darveniza's formula, with those provided by the more detailed model implemented in the LIOV code. The assessment of the accuracy of such a relation is important also for the estimation of the minimum collecting area around the line that includes all dangerous events, which is needed for the calculation of the lightning performance of a power distribution line with a Monte Carlo-based approach. The paper proposes a method for estimating the probability of flashover based on the current peak to distance ratio within the limits of the lightning location systems accuracy.