Two-Component Current Waveform for Lightning Simulation

A new model to simulate return stroke lightning current is presented. The idea for the model arose from the observation that measured lightning current has two quite different parts (fast rise and slow decay). Experimental measurement differentiates three segments in the rising portion: 1) increasing rate of rise, 2) relatively constant rate of rise, and 3) decreasing rate of rise. We propose two functions to represent the return stroke current waveshape, which closely resemble the first and the third segments, and compare them with previously developed models. In fact, we develop two versions of the proposed model: 1) version A: which creates waveshapes close to the waveshapes obtained by the model given in International Standard IEC 62305-1, and 2) version B: which creates waveshapes more similar to the mean waveshapes obtained by the measurement. It is worth pointing out that in both versions we can calculate model parameters using simple formulas.