A review of resonance response in large, horizontal-axis wind turbines

Field operation of the Mod-0 and Mod-1 wind turbines has provided valuable information concerning resonance response in large, two-bladed, horizontal-axis wind turbines. Operational experience has shown that 1/rev excitation exists in the drive train, high aerodynamic damping prevents resonance response of the blade flatwise modes, and teetering the hub substantially reduces the chordwise blade response to odd harmonic excitation. These results can be used by the designer as a guide to system frequency placement. In addition, it has been found that present analytical techniques can accurately predict wind turbine natural frequencies.