Monitoring resonant frequencies and damping values of an offshore wind turbine in parked conditions

Abstract

This study shows the first results of a long-term monitoring campaign on an offshore wind turbine in the Belgian North Sea. It focuses on the continuous monitoring of the resonant frequencies and damping values of the most dominant modes of the support structure. These parameters allow to better understand the dynamics of offshore wind turbines and are crucial in the fatigue assessment during the design phase. They can also help to minimise operation and maintenance (O&M) costs and to assess the lifetime of the offshore wind turbines structures during their operation. To do an accurate continuous monitoring of these parameters, a state-of-the-art operational modal analysis technique has been automated, so that no human-interaction is required and the system can track small changes in the dynamic behaviour of the offshore wind turbine. The study will analyse the resonant frequencies and damping values of the most dominant modes shapes while the wind turbine is in parked conditions. © 2014 The Institution of Engineering and Technology.