Аннотация
White arc and flashover of long rod and porcelain
insulators under glaze and rime icing are studied.
During icing periods ice is accumulated on
the insulator under H.V. applied at a constant temperature
until a flashover occurs or a thickness of ice
measured on a monitoring conductor reaches 7 cm.
During deicing periods, the ambient temperature is
allowed to increase at different rates over the freezing
range. Results show that, for each kind of insulator,
there is a flashover threshold current,
,..hich is 120 mA for the long rod insulator tested,
and 180 mA for the porcelain insulator. Thickness of
ice accretion at which flashover occurs (flashover
threshold thickness) is smaller, during icing period
than during deicing periods. Hard rime, of 0.87 in
density is the most dangerous kind of ice: white arc
and flashover occurs at very low thickness of this
ice. Flashover threshold thickness of ice depends on
the rate of increase of the temperature during deicing
periods. The effect of the wind direction on
insulators flashover performance is also investigated.
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