Real-Time Estimation of Damping in Wind Turbines

Operational Modal Analysis (OMA) is being more and more used as a non-invasive method to asses structural health of civil structures and in particular Wind Turbines (WT), to detect possible failures and to predict the remaining life-time.WT, being rotating structures, pose serious limitations to the use of conventional OMA techniques since the basic assumption of excitation by AWGN does not hold.Unbalances in the rotor and the blade-shadow effect contaminate the acceleration signals with harmonics, hampering a correct determination of modal parameters of the structure.Another limitation is that OMA algorithms are costly in terms of memory and computational resources, and cannot be implemented on site.Thus, data must be massively transferred, from a huge number of WT, and processed off-line.