Wind turbine reliability: A comprehensive review towards effective condition monitoring development

The current work presents a review of wind turbine reliability studies. Thirteen reliability studies were identified in the scientific literature, highlighting the lack of public reliability data. We present the differences across the studies, with great effort being made to unify the various studies to obtain comparable results. To this end, we have endeavoured to develop a wind turbine taxonomy that is common across the different studies, formed by thirteen assemblies, and the failure rates and downtimes from each study have been normalised. The results establish differences between the least reliable assemblies, categorised as critical, and the most reliable ones. Small differences emerge between onshore and offshore locations, and between studies on European wind farms and others in the U.S. and China. The influence on the total failures and downtime of the most recent studies is evaluated against older studies. These results will contribute to elucidate the right direction for condition monitoring design and development, and therefore to improve reliability and availability of wind turbines.