Efficiency of lightning protection of power lines - comparison of estimated and observed failures
International Symposium on Winter Lightning (ISWL), Toyama, Japan, 2001
Lightning is one of the main causes for power line outages. We have correlated HV line outages of either unknown reason or when lightning was already assumed to be the reason, with the archived lightning data from ALDIS for about 25 power lines (400 kV and 220 kV). For about 25% of the outages we found good correlation with a located lightning discharge in a corridor of up to +/- 5000 m. Some of the remaining outages are assumed to be either caused by other severe weather related events (strong wind, moisture on insulators, etc) or by lightning flashes that have not been detected by the lightning location system.
Based on the data archive of the lightning location system ALDIS we have determined values of the actual ground flash densities for the individual lines and we applied the IEEE-FLASH software - which is based on the Electro-Geometric-Model (EGM) - to estimate the number of outages per 100 km and year for each line. For some lines the comparison of the estimated outage rate and the actual observed outage rate are very much different.
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