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.