COMPARISON OF THE BREAKDOWN OF ROD-PLANE GAPS WITH FLOATING ELECTRODE

The possible influence of a metal body in a lightning protection syste m was determined by comparing the electrical breakdown probability of two symmetrical sphere-rod gaps, one conventional and the other with a floating electrode, i.e. a rod with a series gap introduced in its co nducting path. 50 switching voltage impulses were applied to the arran gement for each series-gap length. The breakdown probability was obtai ned for each rod as a function of the series-gap length. The results s how that the rod with a series gap shows the same breakdown probabilit y as the conventional rod for a certain limited range of the series-ga p length. Beyond this range the conventional rod has always a higher b reakdown probability. The analysis of the actual breakdown voltage in different configurations has shown some differences in the physical pr ocess that lead to breakdown in different arrangements.