A Verification of Estimation Accuracy of Lightning Current Waveform and Charge Transfer from Measured E-field Waveform

Abstract

To establish effective countermeasures on power facilities against lightning damage, it is necessary to clarify the lightning characteristics such as current parameters at the area of interest. In order to collect lightning current parameters effectively, the authors have observed electric and magnetic field waveforms simultaneously at south Kyushu, where the lightning flash density in summer is high. Based on observed electric field waveforms, the lightning current parameters have been estimated by adopting the Diendorfer-Uman model (DU model) as the return stroke model. In this paper the accuracy of the estimated return-stroke current waveform is verified by comparison with directly measured return-stroke current waveform, along with the accuracy of the estimated charge transfer from the electric field waveform measured with a slow antenna.

Estimation of Charge Transfer During Long Continuing Currents in Natural Downward Flashes Using Single‐Station E‐Field Measurements

“…Rearranging Equation gives the relation of the charge Q and vertical E‐field at a remote observation point. This model (applied e.g., in Kurihara et al., 2017; Mazur & Ruhnke, 2003; Schumann et al., 2016; Shindo & Uman, 1989; Uman, 1987) assumes a monopole charge at height H above a straight vertical lightning channel at a horizontal distance D from the electric field observation point. If the change of the electric field between the times (n − 1) · Δt and n · Δt is ΔE n = E(n · Δt) − E ((n − 1) · Δt), then the related transferred charge ΔQ n can be calculated using Equation .…”