Within the offshore wind industry, cable pulling contractors have created their own playing field.
Conbit is there to assist them with the final few meters. Global Tech One Offshore Wind GmbH, the offshore wind farm operating company, has entrusted Conbit to assist them with pulling in the cables. The Conbit lifting crew supports the cable pulling company, Prysmian Group.
Conbit has special lifting equipment which can be installed at difficult locations. In this case, the lift booms were installed in two corners of the offshore substation. In these corners the deck crane does not have the required lifting capacity.
In normal operation, the lift booms can handle a load of 5 tonnes, by which the lift booms to slew in all directions. In the configuration chosen at the GT-1 offshore substation, the lift booms have a capacity of 12 tonnes. This increase in capacity is realised by fixing the boom and eliminating the slewing possibility. The lift booms are operated by lift winches, which are incorporated in the lower section of the booms. The length of each boom is 12.7 meters and allowes lifiting with a maximum of 10.8 meters reach.
The foundations of the lift booms are welded directly onto the deck of the offshore substation and the booms are braced in two directions. The luffing pendant is welded to the 1st deck, right above the base of the lift booms.
Before the cables reach the Global Tech 1 offshore substation, the cables need to be laid. This activity is carried out by the cable installation vessel CS Sovereign, operated by Global Marine Systems Energy (GMSE). This vessel installs 95 cables with a total length of approximately 120 km of low voltage cable to connect all 80 wind turbines to the substation. Once the cable arrives at the substation it will be pulled through J tubes on the corners, where the Conbit lift booms are installed. Other J tubes in one of the corners will house the export cable, which will connect the Global Tech One Substation to the Borwin B wind farm. This wind farm is connected to the shore with an HVDC Power Cable, at the town of Diele in Germany.
Conbit’s scope of supply does not end with the lift booms, it also covers two operators for the complete duration of the cable installation process. In addition, back office support is provided to keep the Conbit equipment in operation and to solve many other challenges on board the Global Tech One substation.
Conbit is pleased to be able to keep serving the offshore wind industry. This vibrant sector allows both the engineers in the office and the guys in the field the motivation to get the best out of themselves. This level of motivation gives Conbit the competitive edge when finding the best suitable solutions for the specific challenges. This way, our clients profit the most from this great competence.
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Press release, October 7, 2013; Image: conbit