Long term analysis of line arrester application field study

Lightning is one of the leading causes of interruptions on distribution systems, particularly for utilities that have a medium to high level of lightning activity. In 1997 a field study was conducted to examine the impact of arrester spacing on lightning performance of a 12.5 kV distribution system. Sixty of the worst performing 12 kV circuits, based on historical lightning performance, were analyzed, with half of the circuits upgraded to a test arrester configuration and the other half left alone for comparison. After the arrester upgrades were completed, a paper was published in 2001 to compare the two groups with three seasons of lightning and interruption data. In 2007, the analysis was updated with nine years of lightning and interruption data. This study presents the results of the long-term analysis.