Application of TL Model for Estimation of Current Waveform of Winter Lightning Stroke

Abstract

We studied winter lightning current waveforms measured at the radar tower of Hokuriku Electric Power Company and estimated magnetic field waveforms from the lightning current waveforms using the Transmission Line (TL) model. A lightning current waveform, which is one of important parameters for surge simulations, can be estimated from the magnetic field waveform using the TL model for return strokes. It is necessary to study application of the model for estimation of current waveforms of winter lightning strokes.

Lightning currents were measured at the radar tower using a Rogowski coil and electromagnetic fields radiated from the lightning channels were measured at observation sites more than 12km away from the radar tower in Hokuriku area using an electric antenna and two cross loop antennas. 6 negative lightning currents were measured in winter from 2014 to 2016. The magnetic field waveforms were estimated from the lightning current waveforms using the TL model. The estimated waveforms agreed well with the waveforms measured at the observation sites when the velocities of the lightning current waves were set to 1 × 10⁸ m/s.