Statistical analysis of lightning surges on distribution lines based on the observation

Abstract

SUMMARYProbability distribution of surge discharging current of arresters provided a basis for conventional theory of grounding systems. In order to rationalize the grounding systems, it is necessary to grasp the statistical data of lightning surges on distribution lines caused by direct lightning strokes and indirect lightning strokes. Lightning phenomena on TEPCO's distribution lines had been continuously observed for the rationalization of lightning protection design of distribution lines. The observation had been carried out with still cameras and monitoring sensors of lightning surges. This makes it possible to discover new interesting facts that can be useful for rationalization of lightning protection design of distribution lines. Cumulative frequency distribution of conventional data is close to that of ZnO discharging current in the case of direct strokes and indirect strokes through TEPCO's observation. Moreover, to verify the cumulative current distribution in concrete poles, the authors have compared the cumulative distribution of current through ground lines with that of current through ground lines and concrete poles. The results show that the distribution of current through ground lines and concrete poles is larger than that of current through only ground lines for high currents exceeding 1 kA. This fact suggests that lightning surge current flows not only in ground lines but also in concrete poles.

A study of lightning phenomena on distribution lines based on a lightning‐surge analysis model for direct lightning strokes

“…After reproduction of the measured lightning waveforms, we used the EMTP model for calculation of the transient voltage to confirm the reproduction of the statistical data for the currents and voltages acquired in the observation areas from 1997 to 2001 [5]. Below we present the results obtained for the pole S.O.…”

“…In each area, 100 observation cameras and voltage/current waveform measuring units were installed [5]. Such an observation unit attached to a pole is shown schematically in Fig.…”

Influence of Grounding Resistance Connecting to Surge Arrester on Effectiveness of Lightning Protection Caused by Direct Hit for Power Distribution Lines

“…In recent years, the number of power distribution line faults caused by lightning-induced surges has been declining but the ratio of faults caused by direct lightning hits seems to have become higher [1,2]. Therefore, it is probably desirable to refocus attention from protective measures against lightning-induced surges in distribution lines to efforts aimed at reduction of faults caused by direct lightning strokes [3].…”

Observation Results of Lightning Performance in Distribution Lines

“…Some electric power companies observe lightning strokes to distribution lines using still cameras that are triggered automatically (4) . The Tokyo Electric Power Company (TEPCO) has conducted a field research to measure the waveforms of voltages and currents in order to provide effective preventive measures against distribution line faults due to lightning (5) . Thus, the authors have acquired data that include the characteristics of direct strokes to the actual distribution lines, which are useful for rationalizing lightning protection designs of distribution lines.…”