DC collection networks for offshore generation

Onshore wind farms can now be regarded as a mature technology, capable of providing increasing levels of clean energy. The development of offshore wind technology will provide the ability to harness much larger wind energy resource. Offshore wind arrays present many new challenges including the electrical power system which provides the internal collection system and the connection to the on-shore power network. For remote offshore wind farms, high voltage direct current (HVDC) transmission will be required to transmit power from the wind farm to the shore. The use of HVDC has the effect of decoupling the wind farms internal collection network from the rest of the power grid, thereby removing the requirement for a conventional alternating current (AC) network. This paper discusses the use of a direct current (DC) collection system for offshore wind farms, with particulars emphasis of DC-DC converter requirements. The proposed converter is validated by the simulation model and the performances e.g. switching losses, conduction losses are investigated.