Statistical analysis of component failures: A 16-year survey on more than 550 wind turbines

A good prediction of the failure ratio of wind turbinecomponents is pivotal in order to define a correct maintenanceprogram and reduce the downtime periods. Even a smallfailure can lead to long downtime periods and high repairingcosts. The installation sites, which generally have limitedaccessibility, and the necessity of special facilities to reach thecomponents inside the nacelle, also play a major role in thecorrect management of wind turbines.In this study, a detailed survey on the failures occurred tothe wind turbines managed by the Italian operator "e2i energiespeciali" (more than 550 machines) over 16 years wasperformed and the results were analyzed in detail. Each failurewas classified by considering the damaged component and therelated downtime period. The analysis allowed thedetermination of several useful results such as the trend offailure occurrence with machine age and the identification ofcomponents and macro-components which are more critical interms of both number of occurrences and downtime periods.The combination of component failure occurrences and relateddowntime periods was also computed to estimate whichcomponent is most critical for wind turbine operation.