Availability analysis of VSC-HVDC schemes for offshore windfarms

UK Round 3 offshore windfarms located more than 50km from the shore are likely to require a HVDC transmission system. The availability of these HVDC transmission schemes is a key factor in determining if these offshore windfarms are commercially and technically viable. This paper shows that a typical radial HVDC link would have an energy availability of 96.5% based on estimated reliability indices from publically available data and that the submarine cable is the component which has the greatest effect on the scheme´s availability. The regional HVDC grid analysed in this paper is shown to have a higher energy availability than an equivalent radial scheme, providing additional capacity is built into the grid. Furthermore, cost-benefit analysis shows the link between a scheme´s availability and profitability.