New Functions for Representing IEC 62305 Standard and Other Typical Lightning Stroke Currents

Abstract

New functions for approximating various lightning currents, either measured, assumed or generalized in the standard IEC 62305, are presented in this paper. The channel-base current function and its parameters, as well as analytical expressions of this function derivatives, integrals, and integral transformations are given. Parameters of new functions for representing first stroke currents, subsequent stroke currents, and long stroke currents from the standard IEC 62305 are calculated, so as of two-rise front function typical for experimentally measured first negative stroke currents. Results for lightning electric and magnetic field at different distances from the channel-base obtained by using the proposed function and the Modified transmission line model with exponential decay with height are in good agreement with the results from literature, but any other lightning stroke model can be used as well.