MECHANICAL INTERACTION OF ELECTRICAL TREES AND BARRIERS IN INSULATINGRESINS

It has previously been established by the authors that the mechanical properties of polyester resin, specifically its Young's modulus, tensi le strength and fracture toughness, influence the electrical treeing c haracteristics of that material. A similar dependence for epoxy resin is demonstrated in the paper. For both these materials, a variety of b arrier materials have been introduced mid-way between point-plane elec trodes, and the treeing characteristics are determined over a of tempe rature. The resistance of composite insulation to the growth of electr ical trees has been shown to be determined by the strength of the adhe sive bond between the barrier and the resin matrix as well as by the t hermal and mechanical properties of the resin and barrier materials. A further influential factor is the internal mechanical strain resultin g from the presence of the barrier.