Dielectric Design and Test of 1200 kV Semi-Flexible SF6 Insulated Transmission Line

An SF6 insilated semi-flexible transmiission line is described which uses a corrugated aluminum enclosure to reduce cost and provide flexibility. Dielectric characteristics of a compact 1200 kV design (711mm (28 in) internal diameter enclosure) with SF6 at 440 kPa (50 psig) are established through detailed field plotting and scale model tests. High voltage tests on 550 kV and 1200 kV prototypes then verified that a design using a smooth conductor wiith discrete flexible elements meets the performance and cost objectives. The development was jointly funded by the U. S. Department of Energy and Westinghouse.