Jan De Nul has successfully repaired TenneT’s cable connecting the Trianel Borkum offshore substation with its DolWin alpha converter station.
TenneT engaged Jan De Nul for the repair of a cable fault located within the 500 metre zone around the DolWin alpha platform, 75 km off the German coast north of the island Borkum.
This offshore platform connects three wind farms in the German North Sea to the German extra-high voltage grid.
The repair job is part of the service level agreement for cable repairs that Jan De Nul Group and TenneT entered into in 2019.
Within less than 50 days, Jan De Nul performed the specific detailed engineering, the vessel mobilisation, the replacement of the damaged cable section, as well as the burial of the new cable and joint.
Jan De Nul offshore cables manager Benjamin Foubert said: “Achieving the full repair in such a short notice resulted in a minimal disruption of the offshore grid connection.
“Thanks to the close and pro-active cooperation between all parties involved we were able to complete this campaign successfully, which included our two vessels working simultaneously in close proximity of the offshore platform.”
For this repair job, Jan De Nul mobilised its cable-laying vessel Isaac Newton and multi-purpose vessel Adhemar de Saint-Venant.
Adhemar de Saint-Venant deburied the damaged cable section, including its cable protection system which was buried under large armour rock.
The Isaac Newton loaded the spare cable and repair joint in Emden, recovered the damaged cable section offshore and subsequently installed the new cable and joint with success.
Jan De Nul’s jet-trenching vehicle PT1, installed on-board the Isaac Newton, completed the repair campaign by burying the new cable section 1.5 meters below the seabed.