[M-IS24] Atmospheric electricity: High energy phenomena

[MIS24-P02] Lightning Location and Electrical Properties by ELF Magnetic Field Observation Network in Japan

*Kohei Kabutomori¹, Yasuhide Hobara^1,2, Hiroshi Kikuchi², Takuhiko Ohashi³, Tomonori Shiraishi³ (1.Graduate School of Informatics and Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 1828585, Japan, 2.Center for Space Science and Radio Engineering, The University of Electro-Communications, 1-5-1 Chofugaoka, Chofu, Tokyo 1828585, Japan, 3.TEPCO Power Grid)

Energetic lightning causes serious damage to power grid systems including reusable energy facilities (e.g. wind turbine). For monitoring and mitigation of lightning damage, it is considered necessary to derive the spatio-temporal distribution of lightning and its electrical properties. Peak current and charge moment change have been used to evaluate the damage caused by lightning. ELF(Extremely Low Frequency) electromagnetic observations can estimate the charge moment change from remote locations, but the locating accuracy of lightning is relatively low in comparison to higher frequencies (LF (Low Frequency)). Therefore, the temporal and spatial distributions of lightning and its electrical properties have been derived over a narrow area by using both ELF and LF electromagnetic observations. However, it is suggested that lightning strokes with a small peak current, but with a long continuing current and large total charge may not be detected by the conventional Lightning Location System (LLS) using LF range.
In this study, lightning’s location and electrical properties were derived for the first time only by the ELF magnetic field observation network deployed by the University of Electro-Communications, consisting of three observation stations in Japan. The position of the lightning is determined by the intersection method with error correction for the estimation of the direction of arrival. The position obtained from ELF network is compared with that from LF electromagnetic observations. In addition, the lightning polarity and the charge moment change are derived, and the accuracy of the location and the electrical properties are also evaluated.