Nexans said it has developed three cable technologies to provide transmission system operators with new solutions for their (high voltage direct current) HVDC links.
Namely, the French cable specialist said it has made progress in the development of cross-linked polyethylene (XLPE) insulation, mass-impregnated paper insulation and superconductors.
The XLPE cables, qualified to 320 kV and type-tested at 525 kV, can now be utilized in HVDC power links.
Nexans has fully qualified land and submarine XLPE cable system technology for 320 kV through the combination of type tests and long-term pre-qualification tests, all carried out according to international standards. The same technology principle was applied to achieve a step up in voltage, which led to the successful completion of a type test at 525 kV.
At the same time, the company said it has qualified the first 600 kV mass impregnated cable with a paper-based insulation providing a power transmission capacity of 1900 MW in a bipole configuration.
Mass impregnated HVDC cables are the preferred solution for long-distance submarine transmission of large amounts of electrical energy at the highest voltages. Recent examples include the 100 km subsea element of Canada’s new 900 MW 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.
Superconducting power cables for DC systems
Further to successful tests some years ago at 200 kV, Nexans is engaged in the European project Best Paths aiming at developing a 320 kV DC superconducting power cable system with a capacity of 6,4 GW per bipole, which represents the combined production of multiple nuclear reactors.
This ongoing project is said it should set the basis for the next generation of electric highways and offers innovative solutions to transfer the full transmission power of a HVDC overhead line corridor into one cable system.
“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.”