A review of the state-of-the-art in wind-energy reliability analysis

Reliability analysis can help to identify, classify, and investigate several issues and concepts that arise in wind-energy systems. In this review, we focus on six important aspects according to available literature. First, we focus true reliability model of wind turbines, where different repair models lead to different mathematical models or stochastic processes, some of which are described by point processes, homogenous Poisson process (HPP), and non-homogenous Poisson process (NHPP). Next, we discuss the meaning of the Bathtub curve. Then, we review the role of health-management systems, which are an integral component of wind systems, and which ensure high turbine availability and reliability. The resulting health state is a reflection of the wind systems capability, which can be very useful to wind farm (WF) managers for optimizing the scheduling of maintenance-related activities. Then, we present some reliability testing protocols. A primary objective of reliability analysis is to gain feedback for improving designs. We describe a general design for obtaining the reliability estimation of structural components, and we explain the scale for severity classifications. Finally, we conduct a detailed literature survey to investigate and summarize the research done in wind-reliability analyses.