Prognostic Control to Enhance Offshore Wind Turbine Operations and Maintenance Strategies.

Offshore wind turbines are an attractive source for clean and renewable energy for reasons including their proximity to population centers and their potential for improved capacity factors with better wind resource. However, one obstacle to the more widespread utilization of offshore wind energy is that recent projections of offshore operations and maintenance (O&M) costs vary between 2 to 5 times the costs of onshore O&M. One way to reduce those costs is through a simple yet effective structural health monitoring (SHM) system as part of an overall condition based maintenance paradigm. This paper presents the results of studies that will improve the offshore O&M process and develop a cost-beneficial SHM system. Simulations of damage are performed at multiple model scales to characterize the sensitivity and localization of damage in a blade from operational responses. Concepts for prognostic control strategies are developed for smart load management. A successful SHM system would be able to reduce or eliminate unplanned or unnecessary maintenance as well as reduce logistic lead times and optimize supply chain management through the use of prognostic control operations (e.g. predictive control to mitigate component damage growth or avoid unfavorable operating conditions). Furthermore, by integrating the health of each turbine into the operation and control of the wind farm using a damage mitigating control strategy, the overall economic profit of the wind farm could be increased.