Authors

Abstract

This work involves fiberglass samples used in two kind of aging (45
days aging, 45 days aging with AC of 25 kV). Five sets of fiberglass
samples were used in the accelerated aging tests and each set consists of
nine fiberglass samples. The tested insulation length of these samples was
chosen as 0.3 m. Two metallic bands, upper and bottom, were used as
electrodes and tightly wrapped on the samples. The effect of surface
condition on the materials electric degradation was studied and the nine
samples were divided into' three group. The external surfaces of the first
group of tested samples were kept intact, but some scratches were manually
placed on the external surfaces of the second group. For the third group, five
holes, each with 2.5 cm in diameter, were manually drilled in each sample.
The electric experimental using to identify the insulation strength of
fiberglass materials were (the lighting impulse test, AC wet flashover tests
and, AC dry flashover test).The result show that the CFO voltage and AC
flashover under dry condition were higher than under wet condition for all
samples. The leakage current has a linear relation ship with applied voltage.
The electric degradation is significant when the sample were tested with
electric stress.

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