nkt cables markets the world's most powerful underground DC cable system: 640kV

The build-up of integrated energy systems is strongly driven by the demand for increased renewable energy. The development of cutting-edge and more cost-efficient interconnector systems will enable transmission of power between distant power grids and from remote solar, hydro-power or wind installations over long distances with a minimum energy loss.  A single pair of 640 kV DC cables can transmit enough green energy to supply three million households.

Michael Hedegaard Lyng, President and CEO of NKT Cables, says: "The development of interconnector grids globally represents some of the biggest infrastructure projects of our time, and we are proud to pioneer the associated technology. The interconnector market is expected to grow significantly and with this 640 kV cable system we are underlining our leading position within this promising market."

The new interconnector system will reach a transmission capacity of more than 3 GW which is 20% higher than the existing top solution based on 525 kV technology. The new system is technically and commercially qualified according to the international recommendation Cigré TB 496 and consists of high-voltage cables, oil-free composite terminations based on bushing technology and cable joints for efficient installations. 

The cables are based on the same design and utilise the same DC cross-linked polyethylene (XLPE) insulation material as the company’s 525 kV cable system, a testimony to the robust capacity of this system which has been offered to the market since 2014. The accessories for the 640 kV cable system are the same as for the 525 kV system. The insulation material is developed jointly with Borealis, a leading provider of solutions for the cable and wire industry.

After closing of the ABB HV Cables acquisition on 1 March 2017, NKT Cables has already initiated the process to qualify the plant in Cologne to manufacture high-voltage cables based on DC  technology.

Michael Hedegaard Lyng says: "We can realise significant cross-utilisation synergies by having two plants able to manufacture future DC high-voltage projects. This will provide our customers with both shorter delivery times and a lower risk profile on project execution."