Future needs of high power interconnections solved with gas-insulated transmission lines (GIL)

GIL technology is world-wide in use for more than 30 years, mainly as bus ducts of gas-insulated substations, or as an underground connection in power plants, or as a replacement of an overhead line. The reason for the use of GIL in the past always was high power transmission capability. Now a second generation of GIL is available and has firstly been installed in Switzerland at the Geneva airport and in Bangkok, Thailand, within a substation. This second generation GIL is made for the use over long distances as an alternative to overhead lines and in fields of transmission ratings too high for solid insulated cables. Two main features are shown with the second generation GIL. In this paper the GIL technology is described. Special focus is given on possible applications in China.