Last year, the five-year-old Skagerrak 4 interconnection (SK4), which is one of the interconnections linking the Danish and Norwegian electricity systems, saw three serious faults that made the cable inoperable for extended periods of time. On 6 February, 21 July and 9 October, respectively, sudden faults occurred, shutting down the connection completely. All three faults originated in the SK4 interconnection onshore cable in Denmark.

Energinet and the cable supplier will now dig down to the cable in several places on the section and take samples to find the cause(s) of the three faults. The cable will be cut through, and pieces will be examined by Energinet, by the cable supplier and by experts from an independent company. Sampling work will begin on 25 May and end on 28 July, and the SK4 interconnection will therefore be shut down and remain out of operation for the duration of this period.

Back at full capacity
In order to minimise the risk of further faults, capacity on the Skagerrak interconnections has been reduced from 1700 to 1450 MW since October. The technical solution used in interconnections means that capacity in any given situation is generally asymmetric, and until now has allowed loads of 1387 MW in the primary direction and 950 MW in the secondary direction. Currently, the primary direction is from Norway to Denmark. A new IT-solution has however just raised capacity in secondary direction to 1350 MW.