Development of an EPR tape molded joint (RMJ) for 154 kV 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 environmental impact. In recent years, electrical performances of XLPE cables have been improved; however, increasing demands for power and overcrowding in urban and suburban underground facilities require further improvements to increase current transmission capacities and minimize dimensions. We are investigating the applications of 154 kV XLPE cables with reduced insulation thickness to existing ducts which am already installed. These applications require the development of smaller joints that can be installed in manholes 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 performances of MJ and the interface properties of EPR/XLPE.