Analytical Model for Availability Assessment of Large-Scale Offshore Wind Farms Including Their Collector System
P. Abeynayake, Tom Van Acker, Dirk Van Hertem, Jun Liang
Abstract
With the increase of offshore wind farm size, the use of classical analytical reliability methods becomes computationally intractable. This paper proposes a holistic approach combining multi-state Markov processes and the universal generating function for the availability assessment of radial large-scale offshore wind farms. The proposed model combines multi-state wind turbine output, wind turbine reliability, and inter-array cable reliability models to assess the wind farm output at the point of common coupling. A strategy is developed to split the network into its feeders while still accounting for the wind turbine output dependence, significantly reducing the computational burden. Although the failure rates of inter-array cables are low, their inclusion is pertinent given high repair times and impact on wind farm output given the radial topology of the collection system. A case study on the Anholt wind farm indicates the necessity of accounting for the collection system, showing a significant reduction of 12 % in generation ratio availability for a generation ratio criterion of 95 %.