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Siemens to retrofit one of the largest substations in Germany

Comparable 380 kV 8DQI gas-insulated switchgear will boost the transmission capacity of the Daxlanden substation and are an important part of covering the increased transport demand in German high voltage grid.

During operation, the 400 kV outdoor switchgear with 20 panels will be gradually stripped down in the coming years. In its place, Siemens will build two gas-insulated switchgear (GIS) with 14 and 12 panels during the first expansion stage and 18 and 15 panels, respectively, in the final stage in Karlsruhe. They will more adequately meet the space requirements and simultaneously increase the transmission capacity. The GIS systems are designed specifically to meet the customer's special availability and accessibility specifications. 
The order includes the planning, production, supply, and commissioning of initially 26 switchpanels for the two 8DQ1 GIS systems with triple busbars and single-phase Clean Air bus ducts measuring a total of 3,860 meters in length, and the associated infrastructure equipment. Overall, single-phase bus ducts measuring a total of 5,330 meters in length will be installed.
"We are preparing the substation for the requirements of the energy transition. It will become TransnetBW's largest network node and one of the largest in Europe. So it will be key to national and international power transit from the north to the south and to local supply in the Karlsruhe region", says Dr Werner Götz, CEO of TransnetBW. "With our experienced partner Siemens, we have chosen an environmentally friendly solution that will set standards for the future of energy in Germany."
"With our comprehensive experience with successful retrofitting during operation for transmission grid operators and large industrial plants, we see ourselves as a reliable partner for these projects," says Tim Dawidowsky, CEO EPC Projects at Siemens Gas and Power. "Thanks to the high technical quality of our offer and our recognized skills, we are certain that the region will be well prepared to meet the enhanced requirements resulting from the energy transition."
Industrially treated and purified air, known as "Clean Air," will be used instead of SF6 as the insulating medium for the bus ducts. The Clean Air technology will be used in all of the substation's bus ducts used for connecting overhead lines and transformers as well as in the connecting lines between the two switchgear. The compressed air-insulated components, which can also be used at high operating voltages, have significant benefits over other insulating media. Because operation with compressed air is much more climate-friendly, the retrofitted Daxlanden substation will save approximately 450 million CO 2 equivalents (kg). The switchgear, which emit no toxic decomposition products, can be operated with no additional measures even at extreme temperatures and if malfunctions occur. Operators no longer need to report the quantities of fluorine gas used, while at the same time the quality of service increases. The lower dielectric strength of compressed air is compensated for by appropriately adapted housing dimensions.
The transition to a new energy mix is presenting the German transmission grid with enormous challenges. While energy demand continues to grow, large power plant units in southern Germany that no longer meet the requirements must be taken off the grid. 
TransnetBW GmbH is a German transmission grid operator within the EnBW Group and operates the grid in large parts of Baden-Württemberg as well as in bordering areas of neighboring states.
Additional information on Siemens Gas and Power can be found at
Additional information on high-voltage power transmission can be found at
Siemens Gas and Power (GP) is a global pacesetter in energy, helping customers to meet the evolving demands of today’s industries and societies. GP comprises broad competencies across the entire energy value chain and offers a uniquely comprehensive portfolio for utilities, independent power producers, transmission system operators, the oil and gas industry and other energy intensive industries. Products, solutions, systems and services address the extraction, processing and the transport of oil and gas as well as power and heat generation in central and distributed thermal power plants, power transmission and grid stability, as well as energy transition technologies including storage. With global headquarters in Houston in the U.S. and around 63,000 employees in over 80 countries, Siemens Gas and Power has a presence across the globe and is a leading innovator for the energy systems of today and tomorrow, as it has been for more than 150 years.
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Siemens AG (Berlin and Munich) is a global technology powerhouse that has stood for engineering excellence, innovation, quality, reliability and internationality for more than 170 years. The company is active around the globe, focusing on the areas of power generation and distribution, intelligent infrastructure for buildings and distributed energy systems, and automation and digitalization in the process and manufacturing industries. Through the separately managed company Siemens Mobility, a leading supplier of smart mobility solutions for rail and road transport, Siemens is shaping the world market for passenger and freight services. Due to its majority stakes in the publicly listed companies Siemens Healthineers AG and Siemens Gamesa Renewable Energy, Siemens is also a world-leading supplier of medical technology and digital healthcare services as well as environmentally friendly solutions for onshore and offshore wind power generation. In fiscal 2019, which ended on September 30, 2019, Siemens generated revenue of €86.8 billion and net income of €5.6 billion. At the end of September 2019, the company had around 385,000 employees worldwide. Further information is available on the Internet
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Christina Huemmer

Gas and Power

Freyeslebenstr. 1
91058  Erlangen

+49 9131 17-45722