The substation

The substation works like a “power socket”: This is where the generated electricity flows together, is transformed and sent ashore via a converter platform.

What’s special about the substation at Trianel Wind Farm Borkum is that it also serves as a transformer platform for its sister wind farm, Trianel Wind Farm Borkum II.

One substation – two wind farms: instead of a second platform, both wind farms use the same substation. The farm-internal platform is operated by Infrastruktur Windkraftwerk Borkum GmbH & Co. KG (IWB).

IWB’s task is to keep the substation available at all times so that the electricity generated in the offshore wind farm can be reliably converted and fed into the grid.

The substation consists of many individual components and assemblies that are all important in themselves.

The two main transformers are essential for power generation. Furthermore, there are three large emergency power systems on the substation, which supply both the substation and all wind turbines with energy in the event of a grid failure. Other components include the five-ton platform crane, various rescue equipment, a helicopter landing deck, the fire protection system, telecommunications systems, etc.

Daily tasks of IWB staff consist of planning and carrying out technical maintenance and servicing of these components, as well as organising offshore operations. In addition, monitoring of regulatory requirements, occupational health requirements as well as safety and environmental protection are part of the daily work. 

So it is not only a matter of keeping the technical components working, but also of clear structures that cover operator responsibility and help to safeguard the investment day to day and in the long term. All activities in and around the wind farm have to be controlled, analysed and documented.

Individual wind turbines of an offshore wind farm are usually divided into clusters. Wind turbines in each cluster are connected to each other by submarine cables (inner farm cables) which are laid in a ring or radial pattern within the wind farm leading to the substation. The inner park cabling also belongs to IWB.

The substation serves to reduce the losses and expense of transmitting electrical power from the offshore wind farm to the mainland. It transforms the (AC) voltage generated by the wind turbines from 33 kV to 155 kV via two export transformers. This energy is then transmitted by export cable to the DolWin alpha converter station for high voltage direct current transmission to shore.

The substation is designed for both Trianel offshore wind farms with a total capacity of 400 MW. The electrical design of the two offshore wind farms is such that the substation, wind turbine and inner-farm cabling components are optimally coordinated to meet grid compliance requirements for feeding the generated electricity into the public power grid.

For this purpose, the substation is founded on a jacket construction, where the upper part is called the topside. The topside can be accessed via two boat landings attached to the jacket or via the helicopter landing deck.