Electrical Tree Aging Characteristics of Epoxy Resin under High Frequency at Different Temperatures

Electrical tree aging is a typical electrical aging phenomenon caused by partial discharge within polymeric insulation materials. It is of great significance to understand and restrain electrical tree aging for the insulation package design and reliability improvement of both electrical and electronic equipment. Power electronic insulation is easily affected by high frequency and high temperature. Both voltage frequency and temperature have important influence on the tree initiation, growth, and evolution process. In this paper, according to the electrical tree aging characteristics of epoxy resin under high voltage frequency (10 kHz), electrical tree aging of epoxy resin at high temperature
$(90^{\mathrm{o}}\mathrm{C})$
and low temperature
$(0^{\mathrm{o}}\mathrm{C})$
were compared and analyzed. The result shows that low temperature inhibited the growth of electrical tree channels of epoxy resin. The lower the temperature is, the denser the electrical tree becomes, and the morphology of branches are more complex. Besides, the electrical tree develops perpendicular to the electric field. In contrast, high temperature promotes the development activities of electrical tree aging. With the rise of testing temperature, the color of tree branch channels become lighter. The obtained electrical tree aging characteristics of epoxy insulation commonly used in power electronic packaging provides an important reference for the future research and development of new epoxy materials.