Switchgear | The case for clean air
Fluorinated gases (F-gases) are harmful to the environment, even in small volumes, which means the goal must be to eliminate them entirely from switchgear, argues Dr Ulf Katschinski, senior vice president, switching products and systems, Siemens Energy
Siemens Energy and myself are campaigning for zero greenhouse gas potential and zero risk from F-gases in switchgear products.
F-gas-free switchgear products are already available from Siemens Energy up to a voltage level of 170 kV. It can be proven that these have the lowest lifecycle costs in the industry, and thanks to innovative digital metrology they take up about the same amount of space as their SF6
-
insulated predecessors. These are all facts that will determine the future of switching technology. One point to mention at the outset: in the absence of alternatives, fluorinated gases such as sulphur hexafluoride (SF6
) have long constituted
the most effective and space-saving option for insulating switching media using gas. But it’s a complex substance to deal with. After all, SF6
is the most powerful greenhouse gas we know, and is about 23 500 times more harmful to the climate than CO2
. The
European Environment Agency compares the impact of annual SF6
. And given the
nature of the system, it’s impossible to avoid even a small level of emissions when using SF6
emissions in the EU with the
emissions from 1.3 million vehicles powered by internal combustion engines.
The risk to humans and the environment posed by fluorinated gases is too great. But whereas manufacturers of shoes, windows, and tyres have increasingly banned the gas from their products, it’s still used throughout the world to insulate high-voltage switchgear.
Time for change
Now is the time to change this and usher in an age without fluorinated gases in the energy industry as well.
Size comparison: SF6
-insulated GIS with conventional instrument transformer (right) vs. clean air version with low-power instrument transformer (left)
Many in the industry believe that insulation
and mixtures involving other F-gases will be more strongly regulated by the end of the year in the EU and beyond. The consequences will be immediately evident: more measurements needed for checking purposes, more stringent precautionary measures, and more reporting to the authorities. The result: higher operating costs. We may also have to face high tax
with SF6 consider joint development
Siemens Energy and Mitsubishi Electric
Breaking new ground for dead tank circuit breakers
Siemens Energy has successfully completed the world’s first type approval test according to IEEE/ANSI standards of a completely F-gas-free dead tank circuit breaker for up to 123 kV. The dead tank circuit breaker from Siemens Energy’s Blue portfolio combines clean air insulation and vacuum switching technology. The now fully type approved Blue dead tank circuit breaker is destined for California’s 115 kV grid. Recently, the California Air Resources Board (CARB) has set out proposals to phase out SF6
in the state.
Siemens Energy and Mitsubishi Electric are conducting a feasibility study on the joint development of high-voltage switching solutions employing clean air, with a view to scaling the technology up to higher voltages. They are starting with a 245 kV dead-tank circuit breaker. Both companies have been working for -
many years on the development of SF6
free gas-insulated switching solutions that replace the greenhouse gas with clean air. While circuit breakers that use clean- air and vacuum-switching technology have been available from Siemens for at least 15 years for voltage levels up to 72.5 kV, the performance and low lifecycle costs also make it a good choice for other substation products, including GIS up to 145 kV. Mitsubishi Electric also has extensive
experience with vacuum-interruption and dry-air insulation technology, and started providing its 72.5 kV vacuum interrupter in 2002.
26 | October 2021 |
www.modernpowersystems.com
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