Development of New-Type Outdoor Termination Using Composite Insulator with SF{sub}6 Gas: Commercial Use for 77-kV Transmission Lines and Development for 154-kV XLPE Cable

摘要

Recently, composite insulators have been increasingly employed mainly for economic reasons. We have developed a new type of outdoor termination using a composite insulator, which can be installed horizontally on a steel tower in order to reduce the construction cost. In this outdoor termination, SF{sub}6 gas is filled in the composite insulator and a cold shrinkable premolded rubber unit is applied instead of the combined use of a rubber-molded stress relief cone, epoxy resin insulator and spring unit. The application of the composite insulator, SF{sub}6 gas and cold shrinkable premolded rubber unit reduces the total weight and makes it possible to install the termination horizontally on the tower. The new-type outdoor termination for 77-kV XLPE cable has already been applied in commercial use and enabled a reduction of the construction costs for power transmission lines. A 154-kV new-type outdoor termination has been developed and its initial electrical tests were successfully completed. This paper describes the design and performance of both 77-kV and 154-kV new-type outdoor termination, and a follow-up survey of the 77-kV new termination in a commercial use.