Nexans Advances Its HVDC Cable Technology

Nexans has given a boost to its high voltage direct current (HVDC) cable portfolio with cross-linked polyethylene (XLPE) insulation designs now fully qualified for 320kV and type-tested at 525kV, and mass impregnated paper insulation now ready for 600kV.

HVDC power links are now able to utilize Nexans XLPE cables that are qualified to 320kV, while type testing at 525kV has just been completed. At the same time, Nexans has qualified the first 600kV mass impregnated cable with a paper-based insulation.

The company is also working on superconducting power cables for DC systems.

The land and submarine XLPE cable system technology has been fully qualified for 320kV through the combination of type tests and long-term pre-qualification tests. The same technology principle was applied to achieve a step up in voltage, which led to the completion of a type test at 525 kV.

Mass impregnated HVDC cables are the preferred solution for long-distance submarine transmission of large amounts of electrical energy at the highest voltages, the company said. Recent examples include the 100km subsea element of Canada’s new 900MW interconnection to be constructed between Labrador and Newfoundland. The same cable design is also being used for the Skagerrak 4 interconnector between Denmark and Norway.

Nexans has qualified the first 600kV mass impregnated cable with a paper-based insulation providing a power transmission capacity of 1,900MW in a bipole configuration, and said that such cables are highly competitive for the future realization of high-power HVDC transmission systems.

“These technological achievements demonstrate the efficiency of the organization we recently put in place to speed up developments in the field of HVDC systems”, said Jean-Maxime Saugrain, Chief Technical Officer of Nexans High Voltage and Underwater Cables Business Group. “The cable systems we have developed and successfully tested up to 525 and 600 kV are just the tip of the iceberg. A major effort was made to address specific issues in HVDC systems, in particular issues related to accumulation and mobility of electrical charges. This is of key importance for the long-term reliability of HVDC cable systems and therefore for the satisfaction of our customers.”