NKT was awarded the repair contract after the Kontiskan 2 interconnector – operated by Svenska Kraftnät and Energinet, Denmark, – suffered a fault due to external impact at the end of January 2022. Roughly eight weeks after the fault occured, the 285 kV mass impregnated (MI) HVDC power cable system was back in full operation, while the actual repair operation took only 12 days.
"Once again, we demonstrated that we are among the fastest companies in the market when it comes to offshore repairs. Our repair preparedness enabled us to quickly mobilize a skilled team for the repair as well as the required equipment. With the fast mobilization and efficient collaboration between all parties involved, we were successful in minimizing the outage time and bringing the Kontiskan 2 interconnector back into operation," says Axel Barnekow Widmark, Executive Vice President and Head of Service at NKT
The national grid operators Svenska Kraftnät and Energinet were satisfied with the fast repair of the Kontiskan 2 interconnector.
NKT – in collaboration with JD Contractor – performed the initial fault finding from shore identifying that the damage was located offshore. The damaged cable section was located 33 km from the converter station in Billdal, Sweden, after further pinpointing with the vessel Assister vessel by JD Contractor. NKT completed the repair operation within only 12 days after the mobilization of a third-party repair vessel. Following the operation, NKT buried the power cable at safe water depth to mitigate the risk of external impact.
The Kontiskan 2 was energized shortly after the repair bringing the power cable connection back in full operation. The interconnector was installed in 1988 as an addition to the Kontiskan 1 from 1969 to support the exchange of energy between the Nordic countries by connecting the national power grids in Denmark and Sweden.