Development of an EPR tape molded joint (RMJ) for 154kV XLPE cables with reduced insulation thickness

Cross-linked polyethylene-insulated (XLPE) cables are widely used for extra-high voltage power transmission lines, replacing oil filled (OF) cables due to their advantages in maintenance and environment impact. In recent years, electrical performances of XLPE cables have been improved, however, increasing demands for power and over crowded in urban and suburban underground facilities require futher improvements to incease currently transmission capacities and minimize dimensions. We are investigating the applications of 154kV XLPE cables with reduced insulation thickness to existing ducts which are already installed. These applications require the development of smaller joints that can be installed in man holes for OF cables. Therefore we are developing ethylene-propylene rubber(EPR) tape type molded joint (MJ) methods to improve conventional joint technologies. This paper reports on the relationships between the electrical perfomances of UT and the interface properties of EPR/XLPE.