Siemens Energy , in consortium with Elia , Belgian’s transmission system operator, is developing a gas-insulated switchgear (GIS) for 420 kV lines that operates without any fluorinated gases (F-gases).
The project is co-funded by the EU’s LIFE programme. A pilot system will replace an existing switchgear in Elia’s substation in Vilvoorde, Belgium. A digital low-power instrument transformer is also part of the development project and will be installed at the site, enabling a more compact design.
Most GIS installed in the last 50 years are insulated with the F-gas SF6, which has 24 300 times the global warming potential of CO2 and is the strongest greenhouse gas currently known.
Siemens Energy has been developing a portfolio of F-gas-free alternatives for several years that use a mixture of natural oxygen and nitrogen for insulation, in combination with special vacuum interrupters for switching. These GIS are already available for a voltage level of up to 145 kV.