EU Energy Projects Podcast: SF6-free switchgear with LIFE Blue 420kV GIS

The drive to phase out SF6 as a high global warming potential gas from electricity switchgear has been gathering momentum. Already its ban has been in place in Europe for new MV switchgear starting 1 January, and with new HV switchgear up to 145kV set to follow from 1 January 2028.

This has resulted in the development of alternatives by vendors, as part of which Siemens Energy is leading the LIFE Blue 420kV GIS project, pioneering the use of a natural origin mixture of nitrogen and oxygen, or ‘clean air’ as the company calls it, for use in 420kV switchgear.

“This extraordinary innovation integrates this clean air technology combined with vacuum switching technology, resulting in a switchgear that not only meets but also exceeds environmental and operational standards,” says Kuschel.

“It will offer zero greenhouse gas emissions, and of course, clean air has a global warming potential of zero.”

Alongside this, the project, which is planning a pilot at a substation near Brussels in partnership with the TSO, Elia, is developing a digital low power instrument transformer at the 420kV level. This is also considered a game changer, especially from efficiency and sustainability points of view, with its compact design in line with the next-generation digital substation architectures.

“In addition to the highest measurement accuracy for current and voltage measurement, the wide bandwidth enables power quality monitoring, which is a key function in future with more and more renewables in the grids,” Kuschel comments.

While numerous vendors have had SF6-free products available for years now, what makes the LIFE Blue 420kV GIS a world first is its design for such a high voltage.

“It’s a real technical challenge,” says Kuschel, highlighting the role of digital twin simulation and testing, “and basically we increase the gas pressure and we enlarge slightly the equipment to manage the electrical stresses safely.”

He adds that the thermal management is also very important and that for the short circuit current interruption, vacuum interrupters are being used, some of them connected in series to manage the higher post arc currents.

With 420kV, the highest voltage used commonly across Europe, the LIFE Blue 420kV GIS is expected to be a landmark development, as have those clean air products previously introduced at the 145kV level.

“Successfully developing an F gas-free GIS at this voltage level will demonstrate the feasibility of replacing SF6 in the entire grid without compromising reliability and performance," says Kuschel.

"For us, a global company, other countries use voltage levels above 420kV, such as India and China, and so the 420kV GIS will also be an intermediate step and serve as a blueprint to making the higher voltage levels SF6-free.”

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Listen to previous episodes of the EU Energy Projects Podcast:
BEGONIA and the future of Europe’s digital backbone for energy and mobility
Chronicle, Reflex and EFORT: Strengthening buildings, flexibility and cybersecurity in Europe’s energy system

More about SF6-free switchgear:
First emission-free 420kV GIS based on clean air insulation and vacuum switching
Building resilient grids for a smooth SF6 transition