Closed-loop supervisory control for defined component reliability levels and optimized power generation

Wind turbines are commonly designed for an operating life of approximately 20 years. During development, loads based on a standardized wind site are assumed and the components are designed accordingly. During manufacturing, variance between components and deviations from the nominal component properties cannot be avoided. During operation, loads experienced by a turbine might differ significantly from those assumed during development. Combined, these effects lead to changed actual time to failure. Turbines are either overloaded, making them fail before the end of their design life, or they are running with lower than possible performance and some load bearing capacity is wasted at the end of their service life. To better adapt turbine operation to the actual loads experienced by an individual turbine, we propose the use of reliability control. It is based on a closed-loop adaptation process which changes operating parameters such that performance is maximized, but reliability requirements are met. We present the basic concept and give a detailed introduction to reliability control for wind turbines. We also highlight the current challenges for deployment, which mainly lie in the field of condition monitoring.