Prognostic techniques applied to maintenance of wind turbines: a concise and specific review

Wind turbine installation is growing consistently and fast. Wind turbines are getting bigger in size and power, what incurs that a simple unit breakdown causes large energy losses. They operate under varying, complex and dynamic loads due to the environmental conditions, such as wind shear, turbulence, gusts, etc. Condition-based and prognostic and health maintenance is key to assure reliable and efficient performance of wind farms, especially offshore. Fault diagnosis is important, but given the operational complexity of the wind turbines, previous knowledge about the condition of a wind turbine component and fault prognostics are the state of the art of wind farm operation. Although some advance has been made in the diagnostics of faults of wind turbines, very little research has been carried out in the field of fault prognostics of wind turbines. Then, there is an urgent need to develop prognostic techniques for such complex systems operating in real conditions. This article aims to present a comprehensive, specific and concise review of the up to date efforts and advances in the research of prognostic techniques and remaining useful life estimation methods applied to the critical components of wind turbines and analyse its advantages, capabilities and limitations.