Testing and Condition Monitoring of Composite Wind Turbine Blades

In a wind turbine system, blades are one of the most critical components. They capture energy from wind and convert it to a mechanical energy for electricity power generation. However, once the blades are defective, the power generation efficiency of the turbine will be significantly affected. In worse case when the blade is seriously damaged, the turbine will have to be shut down completely for the sake of safety. Furthermore, they are exposed in direct harsh environment, suffering constantly varying wind loads, experiencing temperature and humidity changes, erosion and corrosion, as well as the cyclic fatigue loads arising from their self-weights in operation. As a consequence, blades are also the most vulnerable component in the entire wind turbine system. The long-term onshore wind farm practice has shown that blade failures account for about 10% of all wind turbine failures reported [1, 2], and result in over 15% of total downtime of the turbines [3, 4], which means a significant revenue loss to operators. Therefore, blade failures have a profound impact on the cost of energy from wind. To improve the reliability of wind turbine blade is of great significance to increase the availability of the wind turbines and economic return from them.