Mechanical interaction of electrical trees and barriers in insulating resins

It has previously been established by the authors that the mechanical properties of polyester resin, specifically its Young´s modulus, tensile strength and fracture toughness, influence the electrical treeing characteristics of that material. A similar dependence for epoxy resin is demonstrated in the paper. For both these materials, a variety of barrier materials have been introduced mid-way between point-plane electrodes, and the treeing characteristics are determined over a range of temperature. The resistance of composite insulation to the growth of electrical trees has been shown to be determined by the strength of the adhesive bond between the barrier and the resin matrix as well as by the thermal and mechanical properties of the resin and barrier materials. A further influential factor is the internal mechanical strain resulting from the presence of the barrier