Offshore Wind Farm Export System Design and Validation – Impact of its Main Parameters

Considering the rapid growth of the wind farms within the offshore wind business, this paper presents a systematic methodology to pre-design the power export system (comprised of the HVAC onshore and submarine cables, and both onshore and offshore reactive power compensation equipment) from the offshore platform to the onshore substation. Furthermore, the paper analyses the impact of the main export system factors that influence the design of the export system. The work carried out has been based in an offshore wind farm around 700MW, with a power export system close to 120km at 220kV. The offshore generation is established at 66kV, and the connection to the transmission operator system takes place at 400kV. The proposed methodology is validated against real measurements. Furthermore, the study of the capacitance and positive sequence reactance of the export cable is revealed as a key factor in the global export system design.