Damping identification of offshore wind turbines using operational modal analysis: a review

Abstract. To increase the contribution of offshore wind energy to global mix in an economically sustainable manner, it is required reduce costs associated with production and operation turbines (OWTs). One largest uncertainties sources conservatism design lifetime prediction for OWTs determination damping level OWT. Estimation OWT based on field measurement data has hence been subject considerable research attention use (preferably operational) vibration obtained from sensors mounted structure. As such, output-only problem can be addressed using state-of-the-art operational modal analysis (OMA) techniques, reviewed this paper. The evolution classical time- frequency-domain OMA techniques reviewed; however, literature shows that are often contaminated by rotor speed harmonics significantly high located close structural modes, which impede identification. Recent advances algorithms known or unknown harmonic frequencies used improve identification such cases. Further, transmissibility family purported insensitive harmonics. Based review, a classification made according set novel suitability criteria, technique appropriate specific setup may selected. Finally, identified most attractive future path estimation lies combination uncertain non-stationary frequency measurements statistical isolation enhance orthogonal removal measured signals, robustification transmissibility-based techniques.