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Siemens develops SF6-free gas-insulated medium-voltage switchgear

The picture shows the 8DAB 12 medium-voltage switchgear.

​"With the addition of the 8DAB 12, we're systematically expanding our portfolio of medium-voltage switchgear," says Stephan May, CEO of the Siemens Medium Voltage and Systems Business Unit. "We'll continue to offer our customers proven vacuum switching technology and single-pole switchgear encapsulation. They can now select the characteristics of the insulating gases used, depending on their requirements. The functionality and dimensions remain the same as the switchgear in our 8DA series." The new blue GIS portfolio is Siemens' answer to the market requirements of customers who want to use both the proven properties of GIS systems in their power grids as well as a non-chemical insulating medium. The blue GIS portfolio represents Siemens' work with insulating media that contain no fluorine gases and meet all the strictest safety and environmental standards.
In recent years, the company has intensively researched alternative insulating materials and technologies that approximate the properties of SF6-based gas mixtures and simultaneously ensure safe and economical switchgear operation. The gas contained in the 8DAB 12 medium-voltage switchgear consists exclusively of natural constituents of the ambient air with no any chemical additives. These constituents are, for example, nitrogen (N2) and oxygen (O2). The 8DAB 12 is a gas-insulated medium-voltage switchgear that works with the proven vacuum switching technology, so the operator benefits from the all the advantages of this technology: no maintenance, compact design, high operating and personal safety, and high availability. Clean air provides the added benefits of easier handling during installation and recycling. In addition, it's not necessary to report the quantity of gas used.
Siemens has been using its vacuum interruption technology in its medium-voltage switchgear for more than 40 years. It's also used in high-voltage systems and recently in switchgear up to 145 kV as well. With vacuum switching technology, when the contacts open the switching arc burns in a metal vapor plasma between the contacts inside the vacuum extinction chamber. The metal vapor condenses back onto the contacts after the arc is extinguished. No decomposition products occur, and the arc doesn't affect the surrounding insulation. This means that natural gases that aren't suitable for extinguishing arcs can be used to insulate the current-carrying conductors.

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For further information on 8DAB 12, please see
Siemens AG (Berlin and Munich) is a global technology powerhouse that has stood for engineering excellence, innovation, quality, reliability and internationality for 170 years. The company is active around the globe, focusing on the areas of electrification, automation and digitalization. One of the world's largest producers of energy-efficient, resource-saving technologies, Siemens is a leading supplier of efficient power generation and power transmission solutions and a pioneer in infrastructure solutions as well as automation, drive and software solutions for industry. With its publicly listed subsidiary Siemens Healthineers AG, the company is also a leading provider of medical imaging equipment – such as computed tomography and magnetic resonance imaging systems – and a leader in laboratory diagnostics as well as clinical IT. In fiscal 2017, which ended on September 30, 2017, Siemens generated revenue of €83.0 billion and net income of €6.2 billion. At the end of September 2017, the company had around 377,000 employees worldwide. Further information is available on the Internet at
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Heiko Jahr

Siemens AG

Freyeslebenstr. 1
91058 Erlangen

+49 (9131) 7-29575