Direct Lightning Strikes to Test Power Distribution Lines—Part I: Experiment and Overall Results

The interaction of rocket-triggered lightning with two unenergized power distribution lines of about 800 m length was studied at the International Center for Lightning Research and Testing in Florida. A horizontally configured line was tested in 2000, and a vertically configured line in 2001, 2002, and 2003. The horizontally and vertically configured lines were equipped with six and four arrester stations, respectively, and, additionally, in 2003, the vertical line with a pole-mounted transformer. During the 2000, 2001, and 2002 experiments, arresters were frequently rendered inoperable by disconnector operation during triggered lightning strokes, but there was no disconnector operation during the 2003 experiment when the transformer was on the line. In all four years, there were commonly flashovers from the struck phase-conductor to the closest phase-conductor not subjected to direct lightning current injection. The self-consistency of measurements is assessed via comparison of the injected lightning current with: 1) the total current flowing to Earth through the multiple line groundings and 2) the total phase-to-neutral current flowing through the line arresters and line terminations. This paper is part one of two related papers.