Active control of the reliability of wind turbines

Wind turbines operation is always a trade-off between reliability and functionality. A turbine's main functionality is power generation, but this induces loads on the structure. These ultimately lead to damage and thus reduce reliability. A suitable trade-off for safe and prolonged operation needs to be found during the design process. During operation, however, the selected trade-off will not be ideal for each individual turbine because of site specific influences. Multiple trade-offs can be obtained with different turbine controller configurations. These allow for an adaptation to the individual reliability and functionality of a specific wind turbine. A closed loop supervisory reliability control for wind turbines is implemented and tested. It is based on a feedback of the current turbine condition and continuously selects the optimal controller from a predefined set of controller configurations. Simulations are conducted to evaluate the effect of reliability control on wind turbine reliability and power production over several years of operating time. Results show that a desired reliability of a wind turbine can be actively controlled even on a slow time scale and with a small number of feasible turbine controller configurations. Reference tracking is sufficiently good despite uncertain wind conditions.