An evaluation of added critical flashover voltage by fiberglasscrossarm to suspension insulators

摘要

Results obtained from lightning impulse measurements on fiberglasscrossarms alone and with three porcelain suspension insulators areexamined. The ratio of critical flashover (CFO) voltage under wet anddry conditions for fiber-glass crossarm is fairly consistent, and forcrossarm with porcelain suspension insulators it is equal to 0.94. TheCFO voltage added by fiberglass crossarms 0-2 ft in length to that ofporcelain suspension insulators is 130 kV/ft for dry conditions and 100kV/ft for wet conditions. For fiberglass crossarms 2-4 ft in length, theCFO voltage added to that of the porcelain string under dry conditionsis 150 kV/ft and under wet conditions is equal to 140 kV/ft