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Abstract

Electrical treeing experiments have been conducted at different temperatures and levels of absorbed moisture in Araldite CY1311 epoxy resin samples above their glass transition temperature, i.e. when the resin was in a flexible state. The fractal dimension of the electrical trees obtained and the rate of tree growth were found to depend on the environmental factors: temperature and humidity. It has also been found that at certain levels of temperature and moisture absorbed in the samples, a transition occurs from electrical treeing degradation to breakdown by thermal runaway. Complementary investigations of the dielectric properties of the same epoxy resin system have revealed that a bulk quasi-dc (QDC) charge transport mechanism takes place above the glass transition temperature, and we show that the characteristic features of the dielectric response are related to the shape of the electrical treeing degradation and the transition to thermal breakdown. This is explained qualitatively through the effect of the bulk QDC charge transport process in modifying the local space charge electric field distribution.

Publication Type:	Article
Additional Information:	© 2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works.
Publisher Keywords:	Epoxy resins, electrical breakdown, electrical trees, charge transport, thermal breakdown
Subjects:	T Technology > TJ Mechanical engineering and machinery T Technology > TK Electrical engineering. Electronics Nuclear engineering
Departments:	School of Science & Technology > Engineering
SWORD Depositor:	Symplectic Administrator

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