Sumitomo Electric Industries, Ltd. is pleased to announce the successful completion of the world’s first type test of its 525 kV direct current (DC) cable system with a gas-insulated direct current switchgear (DC-GIS) interface in accordance to CIGRE*1 TB496 as part of its technical cooperation with Siemens Energy and the German cable provider Südkabel GmbH.

With increased penetration of renewable energy, multipole DC interconnectors will be an attractive option for resilient power grids. DC GIS offer a compact solution, especially for connecting high-voltage direct current (HVDC) cable lines to offshore converter platforms and onshore substations.

Sumitomo Electric has developed a 525-kV DC cable made of cross-linked polyethylene (XLPE)*2, while Siemens Energy has developed a DC GIS component. These companies decided to conduct joint type test at the Mannheim laboratories of KEMA Labs, a CESI brand in Germany. Südkabel supplied its DC XLPE cable using Sumitomo Electric ‘s DC XLPE material and connected it to Sumitomo Electric‘s XLPE cable and joints. These cables were plugged into the Siemens DC GIS via DC GIS terminations.

The joint test results showed the compliance of the 525 kV DC cable system and the DC GIS interface according to CIGRE TB496. Südkabel’s cables were also found to be compatible with Sumitomo Electric‘s cables, while subsequent destructive tests, including reverse polarity tests, showed that both cable systems had adequate margins up to the U0 = 640 kV level.

Sumitomo Electric is a leader in the international power cable industry with its HVDC XLPE insulation technology. In 2019, Sumitomo Electric was awarded the NEMO project, which will connect the UK and Belgium with 400 kV HVDC cables. Sumitomo Electric was also awarded the Corridor A North project, where 525 kV HVDC underground cables will be installed in Germany.

*1 CIGRE, founded in Paris, France, in 1921, is a global community dedicated to the development and exchange of expertise in electrical power transmission and distribution. The community includes thousands of professionals from more than 90 countries and 1250 member organizations, including some of the world’s leading experts.

*2 XLPE stands for cross-linked polyethylene. Conventionally, HVDC projects have used mass-impregnated cables with high-viscosity insulating oil. In recent years, XLPE insulated cables have generally been used due to their high allowable operating temperature and growing environmental concerns.


About Sumitomo Electric Industries

Sumitomo Electric Industries, Ltd. was founded in 1897. Since then, based on technologies for the production of electric wires and cables, we have carried out our original research and development and made intensive efforts to establish new companies. These efforts have enabled us to develop new products and new technologies, as well as to expand our business areas. We currently operate our businesses on a global basis in the following five segments: Automotive; Infoormation Technologies; Electronics; Environment and Energy; Industrial Materials. We contribute to society worldwide through environmentally friendly and fair business activities.
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About Südkabel

Südkabel GmbH, based in Mannheim, specializes in the manufacture of XLPE-insulated power cables and cable accessories for medium, high and extra-high voltage, as well as installation and services. Founded in 1898, Südkabel is one of the most experienced suppliers of cable systems up to 525 kV including planning and engineering with a track record of more than 1500 km of 400/500 kV XLPE cables and more than 3000 systems installed worldwide.

– The Leading Company for High Voltage Cable and Overhead Conductor

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