The role of bulk charge transport processes in electrical tree formation and breakdown mechanisms in epoxy resins

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.

Polycyclic Compounds Affecting Electrical Tree Growth in Polypropylene Under Ambient Temperature

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Self-healing during electrical treeing: A feature of the two-phase liquid-solid nature of silicone gels

“…[13][14][15][16][17][18][19][20][21][22][23][24][25][26]), including silicone rubber [27]. The equivalent breakdown phenomena in liquids i.e.…”

Electrical Tree Growth Characteristics in Epoxy Resin With Harmonic Superimposed DC Voltage

“…The polymer degradation mechanism is relevant to microscopic charge transport and trapping process, which depends on the property of charge carriers [8], [9]. Many literatures have studied the charge transport process during the electrical treeing process.…”