Innopower chooses Nexans technology for China's first High Temperature Superconducting power cable project
The 30-meter long three-phase HTS cable, rated at 35kV and 2kA, will be installed in spring 2004 in the Yunnan Electric Power Group Co Ltd?s power grid. Nexans will supply both the electrical and the thermal insulations.
A CRYOFLEX(r) vacuum-insulated flexible cryogenic envelope will provide the thermal insulation required to maintain the cable core at its operating temperature of about -200°C.
Dr. Ying Xin, General Manager of Innopower, commented : ?We chose Nexans because it is a world leader in flexible cryogenic envelopes, in addition to its broad expertise in cable manufacturing. We have a corporate agreement with Nexans to collaborate in developing HTS cable technology and we look forward to further joint projects in this field. ?
Jean-Maxime Saugrain, Nexans? Superconductor Activity Manager added : ?Flexible cryogenic envelopes have been supplied by Nexans for more than 20 years and we have gained considerable experience through our participation in numerous projects involving cryogenic fluids. This technology is now available for providing the thermal insulation of HTS cables. ?
Note to the Editors
A High Temperature Superconducting (HTS) cable can carry several times more current than a conventional copper cable with the same cross section. The current flows through HTS tapes which exhibit a zero resistance when cooled with liquid nitrogen at about ?200°C. A flexible cryogenic envelope is required to maintain the cable core at this operating temperature. HTS cables are expected to be used in power transmission and distribution networks.
The Nexans CRYOFLEX(r) vacuum-insulated cryogenic envelopes consist of two flexible and concentric corrugated tubes made of stainless steel. The outer part of the inner tube is covered with layers of superinsulation. A spacer with low thermal loss centers the inner tube inside the outer tube and prevents any contact between the two metallic tubes. A molecular sieve guarantees a long-term vacuum. The outer tube may be protected with a polyethylene jacket. The envelopes, together with their associated terminations and hardware, are assembled, leak-tested and evacuated at the Nexans factory. This permits simple and cost saving installation at the customer?s site. The flexibility of the cryogenic envelope enables it to be handled like a cable.