For the first time, two sister platforms in an offshore wind farm will be connected by means of a bridge system with the aid of a new, flexible high-voltage cable with a conductor cross section of 800 mm2. Pfisterer has received the contract for this pilot project within the framework of the connection of the DolWin3 converter station.
In the southwestern area of the North Sea, the DolWin gamma converter platform with a capacity of 900MW is currently being constructed as the third connection within the DolWin cluster. Offshore converter platforms are normally connected directly to the mainland by means of a submarine cable. To be able to switch over between the converter stations when necessary, the two sister platforms, DolWin gamma and DolWin alpha, are sited close together 80 kilometers offshore and linked by means of a bridge with a powerful high-voltage cable. Pfisterer will lay all the high-voltage and medium-voltage cable systems within the platform, as well as the cables on the connecting bridge. The contract with a value of almost € 6 million is being carried out as a turnkey project. The configuration also includes a feasibility study, including dimensioning and calculation of current carrying capacity. The connection between the platforms by means of a highly flexible 155 kV Feltoflex cable will have an overall length of 250 meters. The cable, comprising approximately 4,000 individual strands of wire, is insulated with a special mixture of high modulus ethylene propylene rubber (HEPR). The onshore work to equip the converter station with medium-voltage cable systems has already started, and completion of the HVDC offshore connection is planned by 2017.
