Upgrade of the Öresund connection

The two countries on each side of the Öresund strait are closely connected not only by a bridge but also by several interconnector cable systems. The replaced power link, owned by Swedish national grid operator Svenska Kraftnät, plays an important role in maintaining the transmission security of the two countries. The power flows in both directions, providing energy to businesses as well as to numerous households. The vibrant Öresund region is home to about 3.8 million people. Four LPOF cables produced by us back in 1973 had reached the end of their service life, so they had to be removed and recycled, and the link connecting Helsingborg in Sweden and Helsingør in Denmark had to be upgraded to meet new needs and requirements. New XLPE cables were to be installed at the same location and connected to the substations on each side – all within a time frame of 35 days. Svenska Kraftnät awarded us at NKT the cable system production, jointing and termination works as well as the civil works on the Swedish side. The project was performed in cooperation with our consortium partner Boskalis.

We used our market-leading expertise at our excellent factory in Karlskrona, Sweden, to design, manufacture and test the 36 km of single-conductor 400 kV (kilovolt) high-voltage alternating current (HVAC) XLPE cable systems. Meanwhile, we prepared the sensitive onshore installation sites. We took, for example, measurements to protect the nature reserves, including an old burial ground dating back to the Stone Age and Bronze Age. Boskalis recycled the outdated cables, loaded the new ones onto an installation vessel and performed the offshore installation. Each cable was carefully pulled in through a pipe at landfalls to ensure mechanical protection, time savings and risk reduction. From the substation on each side, NKT specialists installed the onshore cables, routed them to shore and jointed them perfectly to the offshore cables. At the substations, we connected them to terminations. Our high level of experience and knowledge came in handy as we had to manage several parallel activities, and our close cooperation with partners and customers ensured a truly successful project. We completed testing, commissioning and energizing within the challenging deadline.