Development of 275kV Aluminum Conductor XLPE Cable and Connectors

This paper presents the development and evaluation of 275 kV aluminum-conductor XLPE cables and connectors for the planned replacement of Oil-Filled (OF) cables in the Tokyo metropolitan area. Due to rising copper prices, aluminum conductors are being considered as a cost-effective alternative, but they present challenges such as higher electrical resistance, greater thermal expansion, and susceptibility to creep and oxidation. To enable installation within narrow existing troughs, a wire-shielded aluminum conductor cable was developed. The prototype reduced the cable diameter by 11 mm for a 2,500 mm² conductor while maintaining transmission capacity. To achieve reliable cable connections, a compact clamp-type connector using cold spray technology was developed, offering stable contact resistance and easy installation. This connector passed various tests based on CIGRE TB 758 [1]. For aluminumcopper differential connections, good performance was observed after short-circuit testing. The need for new cable cleats suitable for securing cables within narrow troughs is also identified in this study, and their detailed design and testing will be carried out in future work. The developed cable and connector will undergo type tests based on JEC-3408[2], targeting practical application in 2030.