At its substation in Obermooweiler near the historic city of Wangen im Allgäu and north-east of Lake Constance, TSCNET shareholder TransnetBW, one of the four German transmission system operators (TSOs), is planning nothing less than the world’s first gas-insulated switchgear at extra-high voltage level employing alternative and climate-friendly gas technology. The objective is to apply for the first time in practice an innovative type of insulating gas whose greenhouse effect is more than 99 percent lower than that of the currently used sulfur hexafluoride (SF6) and which is equal to or lower than that of CO2.
There are obvious reasons why SF6 has been the industry standard as insulating gas in high-voltage systems for decades: It has excellent electrical properties, is non-toxic and chemically very stable. However, SF6 suffers from a strong greenhouse effect. For climate protection reasons, TransnetBW is thus looking for eco-efficient alternatives. The TSO’s research project aims to provide new insights into the use of an environmentally friendly alternative gas mixture in gas-insulated 380kV switchgears. TransnetBW’s partner in the project, the engineering company ABB, has experiences in the use of alternative insulating gases for switchgears in distribution grids at lower voltage levels. This expertise will now be jointly transferred to the 380kV level.
“The transmission grid integrates renewable energies and is a key element in implementing the energy transition. We also want to promote new solutions for more climate and environmental protection in the design of our grid infrastructure,” explains Dr. Werner Götz, CEO of TransnetBW. The first preparatory construction measures for the new facility are planned for March 2019. As early as 2021, the new switchgear will be connected in a first implementing step. This means an initial SF6 saving of around 55 percent. In the following second step, the existing installation will be converted. From 2026, the entire system will be SF6-free.
TransnetBW has started a research pilot for the use of climate-friendly insulating gas in gas-insulated switchgears at 380kV level (picture based on screenshots taken from video “ABB commissions world’s first switchgear installation with new eco efficient gas”; ABB, YouTube)