With a limited number of kilometers on the Belgian coast line, transmission system operator Elia was looking for a different, more efficient and cost-effective solution than bringing a cable to shore for every new offshore wind farm. Currently, there are already four offshore wind farms in Belgian waters and that number is expected to increase to nine in the near future.
In an international competition, KCI was awarded the Concept Verification and Basic Design of its offshore switch yard (OSY). An OSY is considered a type of offshore power socket, and it is a completely new concept. It will combine the generation power from several Belgian offshore wind farms, combine it, and bring it back to shore.
Until now, all North Sea wind farms have been connected individually to onshore grids. But that is about to change with Elia’s plan for a modular grid that will connect offshore wind farms and bring power to shore through one single OSY.
Creating a modular grid is ideal from a technical, economic, but also an environmental standpoint as it will facilitate shared use of the grid by many wind farms. Moreover, the idea for a modular offshore grid does not limit itself to Belgian waters. Elia and its partners want to be at the basis of laying a direct current offshore grid in Europe.
KCI has just finished the Basic Design of the OSY, which is actually the first design of its kind worldwide.
The outside of the OSY will look like a substation, and KCI has already designed many of those. The inside, however, is quite unique. No transformer is needed inside the platform because the voltage of offshore wind turbines has already been changed in a separate substation from medium to high voltage.
The platform will house 220-kV, gas-insulated switchgear and multiple submarine cable connections. Whereas a substation often has an export cable of around diameter 100 to 150mm, expect the cable of an OSY to be much thicker.