Adjustment of current waveform parameters for first lightning strokes: Representation by Heidler functions

摘要

This paper presents a method for adjusting parameters of first stroke lightning currents, according to measured patterns of their waveforms for negative downward flashes. Waveforms are represented by a sum of Heidler functions, an approach previously adopted by other authors. As published in literature, in order to reproduce important characteristics of first stroke currents, such as the existence of a double peak, several Heidler functions are needed, and parameter fitting is a cumbersome task. The simplicity of the method presented here allows the direct adjustment of each parameter with low computational effort. Thus, this method is suitable for the generation of current waveforms to be applied in evaluating the lightning performance of overhead transmission lines according to a probabilistic-statistical approach.