Rødsand 2 Offshore Wind farm Project - Installation of 145 kV Cable submarine cable:
Clients: ABB AB, Energinet.dk
Date: August 2009
JD-Contractor A/S was involved in the transport and installation of a large transmission cable weighing 73 kg per running metre and a total length of 11.5 km for the Nysted wind project at Rødsand in 2003.
JD-Contractor A/S, with its expertise and knowledge, was therefore contracted in 2009 by ABB to carry out transport and installation of a 145 kV submarine cable to the newly established offshore wind farm, Rødsand 2 in South-Eastern Denmark; in order that the wind farm could be connected to the mains grid on shore.
The following vessels from JD-Contractor A/S’ fleet were used during the assignment: C/B Henry P. Lading (HPL) for cable transport and installation, M/V Buizerd as a support vessel and tugboats T/B Lucas, T/B Thor and T/B Naja.
Prior to laying the cable JD-Contractor A/S was requested to pull the cable through a J-tube on the foundation for the offshore substation platform at the wind farm.
For the laying, a trench was pre-excavated from the shoreline to the trafo-platform and a multi beam survey of the trench was loaded into the navigation system onboard HPL. This allowed the master on HPL to see the position of the vessel in relation to the trench.
To insure that the cable was placed ideally in the trench, a diver monitored the touchdown along the route, and a video feed from the diver was monitored from a supervisor onboard HPL. All diving was carried out in accordance with the offshore diving requirements set by the Danish Authorities. The laying of the cable took 4 days as planned.
As part of the operations requested by Energinet.dk, JD-Contractor A/S de-buried the J-tube and installed a bell-mouth on the tube prior to the first pull-in and subsequently detached the bell-mouth after the pull-in.
After the laying of the cable the pull-in was started. Energinet.dk had made the necessary preparations for the pull-in, though JD-Contractor A/S was overall responsible for the pull-in of the cable at Hyllekrog Beach. During the pull-in, the cable was floated ashore on airbags and pulled up approx. 25 metres on the beach where it was connected to the land cable with a transition joint by ABB.
Divers continued to monitor the cable and removed the airbags as the cable was floated ashore.
In all a length of 9.173 metres of cable was laid; and the work was carried out according to schedule despite bad weather.