Technical report: extrusion-molded joints for world´s first long-distance XLPE cable line

The features of a long-distance underground line, using 275-kV cross-linked polyethylene (XLPE) cable with extrusion-type molded joints (EMJs) are described. The line has a transmission capacity of 440 MW/cct and a 9.5-km section length. The cable has a cross-sectional area of 1400 mm/sup 2/ and insulation thickness of 17 mm. The EMJ, which was developed to withstand the higher stresses of the 275-kV cable, has the following features: (1) the conductor is connected using a copper ferrule, (2) semiconducting heat-shrinkable tubes are used for both inner and outer semiconducting layers, and (3) the insulation unit, applied on top of the stress-relieving cone, is made of insulating and semiconducting XLPE parts cured together in the factory. The fabrication, of the joint is described.<>