Tensile Stress Affecting Electrical Tree Growth in Epoxy Resin Under Temperature Gradient

Under long-term operating conditions, epoxy resin insulation needs to withstand tensile stress and temperature gradients. The article aims to explore the correlation between the electrical tree behavior and tensile stress in epoxy resin under temperature gradient. The tensile stress is applied by a push-pull machine and set to 0, 10, 20, and 30 MPa. As the tensile stress increases, the electrical tree inception voltage decreases and the tree growth rate accelerates, making it easy to form branched electrical tree. The tensile stress aggravates the tree extension in the direction of mechanical stress. The temperature gradient accelerates the degradation of epoxy resin and changes their morphological characteristics of electrical tree. Local temperature rise on the high voltage side results in more severe degradation. The formation of internal defects and molecular chain behavior in epoxy resin affected by stress field and temperature gradient field is explored, and space charge transport behavior is a significant element affecting the tree growth.