Replacement of SF6 by alternatives in 420 kV gas insulated switchgear

German TSO TransnetBW initiated the first pilot projects worldwide with different manufacturers and research institutes, stimulating the development of 420 kV SF6-free gas-insulated switchgear (GIS), while at the same time allowing for safe grid operation.

Highlights:

• First pilot projects worldwide on developing SF6-free GIS at the high voltage level of 420 kV

• Two different gas mixtures (GWP < 1) tested at two different locations

• The use of eco-friendly and climate neutral alternative gases reduces the amount of future grid operation’s emissions and supports the achievement of EU climate targets

About the Practice:

SF6 (sulfur hexafluoride) is the most potent greenhouse gas (GWP 23500) with an extremely long estimated lifetime (3200 years). Through these pilot projects TransnetBW intends to gather own experience with the alternative gases, progressively replacing the SF6 in one GIS (Obermooweiler Substation) and significantly reducing its amount in the other one (Daxlanden Substation, 63 % less SF6). Within the scope of the projects, the company is also redefining the gas handling procedures ensuring a safe grid operation. To achieve these goals, TransnetBW works closely with the Swiss Federal Institute of Technology Zurich, HITACHI ABB Power Grids and SIEMENS Energy.