Burnthrough Of GIS Enclosure Due To Power FaulT ARCS

Enclosure burnthrough in gas insulated substations due to power arcs has to be prevented for personnel safety and operational reasons. Many studies on burnthrough have been published giving different experimental results. Thus, the estimation of burnthrough times on the basis of this published data seems difficult. This paper summarizes the present status of experimental and theoretical studies on burnthrough and shows, that the data appears more homogeneous if the experimental conditions are considered. Formulae based on theoretical analysis seem less practicable than those empirically found. One of these empirical formulae gives reliable and conservative estimates of burnthrough times in actual equipment and is recommended for general use. In the discussion of actual field experience it is emphasized that auto-reclosing in GIS increases the risk of burnthrough and thus the practice should be very carefully reviewed. Areas requiring further investigations are indicated.