Next generation HVDC network for offshore renewable energy industry

The growing demand on non-fossil fuel energy has escalated the desire for mega-scale renewable energy power generation. This demand can no longer be satisfied by solely relying on onshore renewable energy power plants (i.e. onshore wind farms, PV farms, etc.). Outcomes from a recent project funded by the Sixth European Union Framework Programme (FP6), “Project Upwind” concluded that larger offshore wind turbines (i.e. >10MW) are feasible and offer an opportunity for a strategically important area. It will be beneficial for such future large scale renewable energy power generators (i.e. large offshore turbines) and plant (i.e. large offshore wind farms) to have a dedicated high efficiency, robust, flexible and low cost power collection, transmission and distribution technology. Proposed in this paper is a compact and effective hybrid HVDC transformer. The aim is to realise a highly robust and financially rewarding next generation multi-terminal HVDC power collection, transmission and distribution system for future offshore renewable energy power plant. This concept potentially allows the elimination or minimisation of the need for a centralised local offshore HVDC platform or substation in each wind farm, solar farm, tidal farm or wave farm. By not using the line frequency components, it is possible for the proposed power collection system (i.e. the hybrid HVDC transformer) to be designed in such a way that, at the generator site, it is compact enough to fit within the nacelle or tower of an individual turbine. This paper discusses the study outcome of the proposed hybrid HVDC transformer and the application of a multiterminal HVDC system in the renewable energy industry, compared to the existing HVAC and VSC type HVDC systems.