Lightning Channel-Base-Current Estimation Using Engineering Return-Stroke Models From Measured Magnetic Field Based on Deconvolution Method

Estimation and analysis of the lightning channel-base-current (CBC) are essential requirements in the process of designing protection systems against lightning strokes. Thus, a new method is proposed to evaluate the lightning CBC based on the measured magnetic field using the deconvolution method. Engineering return-stroke models, such as transmission line (TL), modified TL with linear current decaying with height (MTLL), and modified TL with exponential current decaying with height (MTLE) models are effectively utilized in the evaluation of lightning CBC from the measured magnetic field. The data of measured magnetic field above the ground surface at four radial distances from the lightning channel, reported in the literature, are considered as input to the proposed method. The peak of lightning CBC is calculated for return-stroke velocities in range one-third to two-third the velocity of light in free space, specifically at 100, 125, 150, 175, and 200 m/mu s for aforementioned measured magnetic field data using MTLE, MTLL, and TL models. The variations in the peak currents, corresponding to the variation in return-stroke velocities, are also observed. Closeness in the peak of simulated CBC between each of the models used in the study is analyzed and reported. Furthermore, this approach will be helpful for better understanding while designing protection systems against lightning.