AbstractThis paper presents an availability analysis of a multistate infrastructure in the case of regular inspections and renewals, given the assumption that an infrastructure is renewed after exceeding a certain threshold by the infrastructure risk function. In the latter case, the procedure of a condition-based maintenance strategy is proposed. A wind farm infrastructure located in the North Sea is considered a case study. The identification and prediction of its reliability are performed, distinguishing three reliability states and assuming that its components have Weibull reliability functions. This paper takes into account the multistate process of infrastructure degradation and includes infrastructure inspections and repairs, and applies the multistate approach to a maintenance and availability analysis of a wind farm infrastructure using its reliability indicators. In its reliability and availability analysis, three periods of “early,” “random,” and “wear-out” failures are distinguished. The results of a comparative analysis of wind farm infrastructure assuming various reliability structures that correspond to its output power differ significantly. Thus, determining at what minimum number of operating wind turbines the infrastructure ensures sufficient efficiency is crucial for analyzing its reliability and availability.