Impulse Voltage Performance ofIce-Covered PostInsulators

Inthis paper arepresented theresults oflaboratory investigations ontheinfluence ofatmospheric icing onthe flashover performance ofpost type insulators under lightning andswitching impulse voltages. Using the"UpandDown" method, thecritical flashover voltages (V50) ofanice-covered post insulator under both positive andnegative lightning and switching impulse voltages wereexperimentally determined in aclimate chamber attheCIGELElaboratories. Thedifference between theproperties ofanice-covered insulator under lightning andswitching impulse voltages wasanalyzed. The possible mechanism underlying this difference wasexplored. Theresults maybeuseful foramoreadequate design and selection ofinsulators forcold regions.