New variable health threshold based on the life observed for improving the scheduled maintenance of a wind turbine

This paper presents a new health threshold used in the MACOL model guided by a non-overpass of a stress limit for a component according to its health condition and technical and economical feasibility. This new health threshold will help to reschedule the programmed maintenance in a dynamical form according to the life evolution of the industrial component analyzed. The core of this study is the analysis of the degradation rate of each significant wind turbine failure mode in order to determine the health limit and the moment when the risk of failure is high. In the case that this health limit is close to being reached, maintenance actions are suggested to be executed by the maintenance model in order to keep the levels of stress at a desired point. Some real examples of application of these new concepts in failure modes of a wind turbine will be described.