운방전에 의한 뇌전자장 펄스의 특성

초록

Abstract - Recently, one of the topics concerning on electromagnetic interference and electromagnetic compatibility(EMI/EMC) is the protection of electronic circuits against transient voltages caused by not only by lightning return strokes but also by induced lightning discharges. In this work, in order to obtain the detailed information about lightning electromagnetic pulses, the electromagnetic pulses radiated from intracloud discharges were measured, and their characteristics and waveform parameters were analyzed statistically. The electromagnetic pulses produced by intracloud discharges are distinctly different with those by lightning return strokes. The zero-crossing times and the full pulse widths of the large bipolar electromagnetic pulses are gradually decreased as the stroke proceeds. Also, the electromagnetic pulses tend to be bipolar, with narrow and fast leader pulses superimposed on the initial half cycle. The mean numbers of leader pulses superimposed on the initial half cycle were 1.61± 0.74 and 1.75 ± 0.73 for the positive and negative polarities, respectively.