Two methods for estimating aeroelastic damping of operational wind turbine modes from experiments

• DOI: 10.1002/we.187
• Publication Date: 2006-01-05T13:12:23Z
• Authors: M. H. Hansen; K. Thomsen; P. Fuglsang; T. Knudsen
• Keywords: Operational Modal Analysis; Aeroelasticity; Mistuning; Damping ratio; Damping torque; Natural frequency

Abstract The theory and results of two experimental methods for estimating the modal damping a wind turbine during operation are presented. Estimations aeroelastic operational modes (including effects aerodynamic forces) give quantitative view stability characteristics turbine. In first method estimation is based on assumption that mode can be excited by harmonic force at its natural frequency, whereby decaying response after end excitation gives an estimate damping. Simulations experiments show vibrations related to tower bending blade pitch generator torque variations. However, not pure estimated therefore actual second stochastic subspace identification, where linear model alone from measured signals assuming ambient turbulence random in time space. Although satisfied, this analysis handle deterministic excitation, frequencies edgewise whirling extracted. Copyright © 2006 John Wiley & Sons, Ltd.