Siem Offshore Contractors Starts Laying Inter-Array Cables at Nordsee One

Siem Offshore Contractors GmbH ( SOC) has started laying the first inter-array cable in the construction area of the 332MW Nordsee One offshore wind farm.

The wind farm’s 54 6.15MW turbines will be connected to the offshore substation by ten strings of cables with an overall length of approximately 70 kilometres.

Tim Kittelhake, Managing Director (COO) of Nordsee One GmbH, said: “In the last month we have successfully installed all 54 foundations for the wind turbines, as well as the foundation for the offshore substation. We plan to install the substation this summer. Currently, we are beginning the cable laying process. First, the cables are laid, and then they are buried into the sea bed by a specialized cable laying vessel. We expect to finish the complete inter-array cable laying works this fall.”

Siem is in charge of supplying and installing the inter-array cables for Nordsee One. The submarine cables have a diameter of up to 160 mm. A layer of steel armour wire protects the high-performance electricity connectors from extreme conditions, which, in particular, may occur during installation.

Pierre Lestienne, Managing Director (CFO) of Nordsee One GmbH, said: “All 54 wind turbines will be connected via the inter-array cables to this offshore transformer substation. This is where the 33 kV power generated by the wind turbines will be converted into a transmission voltage of 155 kV.”

Nordsee One is owned by Northland Power Inc. (85%) and RWE International SE (15%). The wind farm is located approximately 40 kilometres north of the island of Juist in the German part of the North Sea.

The commissioning is scheduled for 2017.

Photos: RWE Innogy