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Electric supply reliability is an issue of wide importance to both an information-oriented society and electric power companies. This paper focuses on lightning effects on distribution lines. Field research is now underway in the northern part of the Kanto Plain in Japan, and voltage and current waveforms in distribution lines due to lightning hits have been observed since 1996. There are now 284 datasets; these include data on 62 direct flashes to lines. This research reveals that a distribution line can be protected from direct lightning strokes. In some cases, no power follow current was confirmed after a multiple phase flashover, and a statistical analysis was conducted to investigate factors affecting the generation of power follow current. These results can serve as a valuable resource to help clarify the mechanisms underlying the production of distribution-line faults caused by lightning effects. [ABSTRACT FROM AUTHOR]

As society becomes ever more dependent on electronics, interest in the patterns of lightning hazards in low-voltage distribution lines including residences is growing. However, there have been few studies on low-voltage distribution lines and many things remain unknown about the propagation patterns of lightning surges in the field, particularly the intrusion of lightning surges into residences. The Tokyo Electric Power Company has conducted field research of phenomena accompanying lightning flashes to actual distribution systems using lightning-activated cameras as well as lightning surge waveform detectors, obtaining invaluable 101 datasets of lightning flashes between 2002 and 2007. This paper analyzes typical observation examples and estimates the lightning surge propagation routes in low-voltage distribution lines. In some examples, it is inferred that a lightning current flowed in the reverse direction from the residence to the low-voltage distribution line caused by ground potential rise due to the nearby lightning to the ground. These results will be useful for clarifying lightning surge propagation patterns in low-voltage distribution lines. [ABSTRACT FROM AUTHOR]

Abstract-Field study of lightning stroke effects, particularly the mechanisms that produce distribution line faults, is essential for designing rational lightning protection for distribution lines. The Tokyo Electric Power Company has conducted photographic research and observed voltage and current waveforms due to lightning in actual distribution lines since 1996, obtaining 284 datasets, including 62 for direct hits to the lines. These results permit a comprehensive study of each lightning flash; the photographs show the precise location of the lightning, and the waveforms provide detailed analyses of flashovers in the distribution systems. This paper evaluates typical observed datasets, including surge insulator voltage waveforms. In some cases, the direct lightning strokes did not cause distribution line faults because the power follow current extinguished spontaneously after flashover generation. These results provide a solid basis for examining the mechanisms underlying the production of distribution line faults, and can lead to effective lightning protection practices. [ABSTRACT FROM AUTHOR]

The Tokyo Electric Power Company had conducted field research of voltages and currents in actual distribution lines due to lightning strokes between 1997 and 2001. These results confirm that the distribution line faults are mainly caused by direct lightning strokes to the line. Thus, it is important to simulate lightning performance for direct strokes to establish a lightning protection design of distribution lines. In this paper, statistical data of the observed voltages and currents are analyzed, and the validation of the observation results for the direct lightning strokes using a lightning surge analysis model is conducted. The observation results and the simulation model are useful in clarifying lightning performance in distribution lines. [ABSTRACT FROM AUTHOR]