A wind turbine generator comprising at least one oscillating damping arrangement

An oscillation damping arrangement arranged within a blade of a wind turbine generator, the wind turbine generator comprising:

• a support structure including a tower;
• a nacelle connected to the tower;
• and
• two or more blades mounted on a hub connected to the nacelle;
• wherein:
• the at least one oscillation damping arrangement is tuned to one or more common frequencies (fcommon) of at least one coupled mode oscillation, such that the at least one coupled mode oscillation is mitigated by the at least one oscillation damping arrangement;
• the at least one coupled mode oscillation at the one or more common frequencies is a combination of oscillations of the support structure and oscillations of at least one of the two or more blades;
• and
• the oscillations of the support structure and the oscillations of the at least one of the two or more blades are caused by forces transferred through the support structure at seismic activity in the ground where the support structure is positioned.

A blade of a wind turbine generator, the wind turbine generator comprising:

• a support structure including a tower;
• a nacelle connected to the tower;
• and
• two or more blades mounted on a hub connected to the nacelle;
• the blade comprising:
• at least one oscillation damping arrangement being tuned to one or more common frequencies (fcommon) of at least one coupled mode oscillation, such that the at least one coupled mode oscillation is mitigated by the at least one oscillation damping arrangement;
• wherein
• the at least one coupled mode oscillation at the one or more common frequencies is a combination of oscillations of a support structure and oscillations of at least one of the two or more blades;
• and
• the oscillations of the support structure and of the at least one of the two or more blades are caused by forces transferred through the support structure at seismic activity in the ground where the support structure is positioned.

A method for mitigating at least one coupled mode oscillation of a wind turbine generator, the wind turbine generator comprising:

• a support structure including a tower;
• a nacelle connected to the tower;
• two or more blades mounted on a hub connected to the nacelle;
• and
• at least one oscillation damping arrangement arranged within at least one of the two or more blades;
• the method comprising:
• determining one or more common frequencies (fcommon) of at least one coupled mode oscillation being a combination of oscillations of the support structure and oscillations of at least one of the two or more blades, wherein the oscillations are caused by forces transferred through the support structure at seismic activity in the ground where the support structure is positioned;
• and
• tuning the at least one oscillation damping arrangement to the determined one or more common frequencies (fcommon).

A method for assembling a wind turbine generator, the method comprising:

• erecting a support structure including a tower;
• connecting a nacelle to the tower;
• mounting two or more blades on a hub connected to the nacelle;
• determining one or more common frequencies (fcommon) of at least one coupled mode oscillation being a combination of oscillations of the support structure and oscillations of at least one of the two or more blades, wherein the oscillations are caused by forces transferred through the support structure at seismic activity in the ground where the support structure is positioned;
• arranging at least one oscillation damping arrangement within at least one of the two or more blades;
• and
• tuning the at least one oscillation damping arrangement to the determined one or more common frequencies (fcommon).

A power plant configured to provide electric power to an electric power grid, wherein the power plant comprises a plurality of wind turbine generators;

• wherein at least one wind turbine generator of the plurality of wind turbine generators comprises:
• a support structure including a tower;
• a nacelle connected to the tower;
• two or more blades mounted on a hub connected to the nacelle;
• and
• at least one oscillation damping arrangement arranged within at least one of the two or more blades, the at least one oscillation damping arrangement being tuned to one or more common frequencies (fcommon) of at least one coupled mode oscillation, such that the at least one coupled mode oscillation is mitigated by the at least one oscillation damping arrangement;
• wherein:
• the at least one coupled mode oscillation at the one or more common frequencies (fcommon) is a combination of oscillations of the support structure and oscillations of at least one of the two or more blades;
• and
• the oscillations of the support structure and the oscillations of the at least one of the two or more blades are caused by forces transferred through the support structure at seismic activity in the ground where the support structure is positioned.