Development and Installation of 275KV SF6 Gas-Insulated Transmission Line

In order to install a commercial 275kV gas-insulated transmission line (called GIL by the authors) on a route with many bends and inclines, a temperature rise test and long-term field test were performed to confirm the current capacity and thermo- mechanical and dielectric characteristics. Fault location and leakage gas removal tests were carried out to evaluate maintenance methods. Based on satisfactory results in all these tests, two circuits of 275kV GILs were installed to connect a gas-insulated substation of the Kansai Electric Power Co., Inc. to an overhead line.