On the tangential AC breakdown strength of polymer interfaces considering elastic modulus

The interfacial breakdown between two dielectric surfaces was reported to represent one of the leading causes of failure for power cable joints and connectors, in which elastic modulus of the dielectric material plays a key role. The primary motivation of this paper is to study the influence of the elastic modulus of the polymer insulation on the tangential AC breakdown strength (BDS) of polymer interfaces experimentally. In the experiments, four different materials with different elastic moduli were employed under various contact pressures: polyether ether ketone (PEEK), cured end product of epoxy resin (EPOXY), cross-linked polyethylene (XLPE), and silicone rubber (SiR). The BDS of each interface increased as the contact pressure was augmented. As the contact pressure became threefold, the interfacial BDS rose by a factor of 2.4, 1.7, 1.8, and 1.4 in the case of the PEEK, EPOXY, XLPE and SiR interface, in a sequence following the decrease of the elastic modulus. Under the same contact pressure, it was observed that the lower the elastic modulus, the higher the BDS.