June 26, 2019
3 min read

First SF6-free voltage transformers for 420 kV

Siemens Energy has been awarded its first order to deliver six newly developed 420 kV Blue voltage transformers by a German transmission system operator (TSO). Hereby Blue products enter the highest available voltage range in Germany of 420 kV. A further step to a sustainable and reliable power transmission.

Blue portfolio enters 420 kV voltage range

Worldwide, many TSOs intend to eliminate greenhouse gases for new installations of gas-insulated equipment and therefore continue to contribute to their voluntary self-commitment in SF6 reduction. Until now, SF6-free voltage transformers were available for voltages up to 245 kV. Recently, Siemens Energy has succeeded to expand the Blue portfolio, which exists of a broad spectrum of COequivalent-free equipment for air-insulated and gas-insulated switchgear, with a 420 kV voltage transformer. Hereby Blue products enter the highest available voltage range in Germany of 420 kV.

No greenhouse gas but compact and powerful

The insulation medium of the Blue instrument transformers has no impact on the environment, therefore the Global Warming Potential is zero. SF6 or other fluorinated gases, called F-Gases, are replaced by applying dry synthetic air, so called „clean air“, as an insulation medium for gas-insulated equipment. Clean air consists of 80% nitrogen and 20% oxygen, natural elements in the surrounding atmosphere.

With this new technology, there is no longer an obligation for F-gas reporting. This Reporting is mainly required in the EU. Extensive safety requirements during the handling of F-gases are no longer necessary. The risk of F-gas-emission – which is very low during operation – is completely eliminated.

In parallel, blue instrument transformers are extremely powerful and space saving: They operate reliably at temperatures below minus 50 degree Celsius, without additional heating, and have the same space requirements as SF6-filled voltage transformers, in the same voltage range. Scientific research of Siemens Energy former Siemens and its affiliated company Trench, with more than 70 years of experience in the manufacturing of instrument transformers, made it possible to transfer this innovative technology to a voltage range of 420 kV.

Maintenance free and sustainable

The operator benefits, as the instrument transformer is completely maintenance free during its lifetime.

“Sustainability is of increasing significance for our customers and ourselves. Our SF6-free Blue portfolio combines all aspects of highest quality and performance with environmental friendliness. We are convinced that blue instrument transformers are an important component for a worldwide sustainable energy transmission, “says Dr. Beatrix Natter, Executive Vice President Siemens Energy Transmission.

By producing innovative SF6-free Blue instrument transformers Siemens Energy is contributing to the United Nations Sustainable Development Goals number 7, number 9 and number 15: “Ensure access to affordable, reliable, sustainable and modern energy for all”, “Build resilient infrastructure, promote inclusive and sustainable industrialization and foster innovation” and “Life on land”.

Siemens Energy Transmission

Transmission products play a vital role in the energy value chain. Siemens Energy Transmission offers all key elements including power transformers, gas-insulated and / or air-insulated switchgear and components, individually or bundled, with related engineering. With our global factory network and leading innovations we provide the highest level of quality and reliability to support our customers in achieving their objectives.