Offshore installation services firm Jan De Nul said Tuesday it had repaired TenneT’s AC108 cable connecting the Trianel Borkum offshore substation with Tennet's DolWin alpha converter station in the North Sea, offshore Germany.
The repair job is part of the Service Level Agreement for cable repairs that Jan De Nul Group and TenneT entered into in 2019.
TenneT engaged Jan De Nul Group for the repair of a cable fault located within the 500-meter zone around the DolWin alpha platform, 75 kilometers 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 and is vital for these wind farms to be able to get electricity ashore.
"Within less than 50 days, Jan De Nul performed the specific detailed engineering, the vessel mobilization, the replacement of the damaged cable section, as well as the burial of the new cable and joint," Jan De Nul said.
Jan De Nul dispatched its Cable-Laying Vessel Isaac Newton and Multi-Purpose Vessel Adhémar de Saint-Venant for this repair. The Adhémar de Saint-Venant began by unearthing the damaged cable portion, as well as its cable protection system, which had been buried under large armor rock.
The Isaac Newton vessel loaded the spare cable and repair joint in Emden, Germany, recovered the damaged cable section offshore, and then installed the new cable and joint. 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.