Quick summary

The electrical systems of an offshore wind farm consist of many individual components.  The main ones are listed below:

  • Offshore substation – The subsea cables from all the wind turbines connect to this substation;
  • Inter-Array Cables (IAC) – These cables run from wind turbine to turbine rather like a daisy chain, in strings up to 10 turbines long, and return to the offshore substation.  They operate at either 33 or 66kV (kiloVolts);
  • Export cable – This is a single cable that runs from the offshore substation usually to land and the onshore substation.  It is longer than the IAC’s and will operate at a higher voltage, for example 220kV;
  • Onshore substation – This connects the export cable to the onshore national grid system.  It is usually located near to the beach where the cable comes ashore;
  • (Optional) Reactor station – If the export cable is very long it will require at least one reactor station (rather like a small offshore substation) to compensate for reactive power;
  • (Optional) Collector station – In some countries it is required that the offshore wind farm connects into an offshore collector station instead of bringing the power onshore.  This is usually a government owned asset.
offshore wind farm substation

1. Offshore substation key features

2. Inter Array Cables

3. Export cable

4. Onshore substation

5. Cable termination works and commissioning