The invention relates to a method and a system for adjusting the torque of a mass and spinning wheel rotator in a wave power plant. The torque of a rotator rotating around a vertical shaft is compensated partially or completely with a compensating moment which is produced by an electric machine. Acceleration components (.sup.ACCx and .sup.ACCy) are measured for a given point of the wave power plant's floating body (1) in directions perpendicular to each other. A vector (V.sub.xy) with a magnitude formula (A) and a direction (a.sub.Acc) is established for said acceleration components, the direction or angular position (a) of a rotator (2) is monitored and its lag (α.sub.LAG) from the acceleration vector's direction (α.sub.Acc) is determined. The compensating moment is adjusted as dependent on a compensation factor (B) whose sub-factors are the magnitude of the body's acceleration vector (V.sub.xy) and the sine of the angle of lag (sin α.sub.LAG). This is supplemented with a compensation factor based on spinning wheel forces in a manner otherwise similar except that the acceleration must be replaced with a rotation speed (AV.sub.x-y) of the body's inclination, which is obtained from an inertial sensor 821). and the mass must be replaced with a gyro force which is dependent on the inertia and rotating speed of a spinning wheel.

A method of operating a wind turbine comprising a generator in the event of a voltage dip is disclosed. The method comprises detecting an end of the voltage dip, determining an acceleration of a rotor of the generator, and increasing a torque of the generator when the end of the voltage dip is detected according to a selected torque profile. The selected torque profile is selected from a plurality predetermined torque profiles, wherein the predetermined torque profiles describe torque as a function of time. The selected torque profile is selected based on the determined acceleration of the rotor of the generator. Also provided are wind turbines configured for such methods.

A method of operating a wind turbine comprising a generator in the event of a voltage dip is disclosed. The method comprises detecting an end of the voltage dip, determining an acceleration of a rotor of the generator, and increasing a torque of the generator when the end of the voltage dip is detected according to a selected torque profile. The selected torque profile is selected from a plurality predetermined torque profiles, wherein the predetermined torque profiles describe torque as a function of time. The selected torque profile is selected based on the determined acceleration of the rotor of the generator. Also provided are wind turbines configured for such methods.

A method for mitigating damage in a rotor blade of a plurality of rotor blades of a wind turbine includes receiving a plurality of acceleration signals from the plurality of the rotor blades in at least one direction. The method also includes generating a spectral density for each of the plurality of acceleration signals. Further, the method includes determining blade energies for each of the plurality of rotor blades based on the spectral densities for each of the plurality of acceleration signals for at least one predetermined frequency range. Moreover, the method includes comparing the blade energies to at least one of each other or a predetermined damage threshold. In addition, the method includes implementing a control action when one or more of the blade energies vary from each other by a predetermined amount or one or more of the blade energies exceed the predetermined damage threshold.

A method for mitigating damage in a rotor blade of a plurality of rotor blades of a wind turbine includes receiving a plurality of acceleration signals from the plurality of the rotor blades in at least one direction. The method also includes generating a spectral density for each of the plurality of acceleration signals. Further, the method includes determining blade energies for each of the plurality of rotor blades based on the spectral densities for each of the plurality of acceleration signals for at least one predetermined frequency range. Moreover, the method includes comparing the blade energies to at least one of each other or a predetermined damage threshold. In addition, the method includes implementing a control action when one or more of the blade energies vary from each other by a predetermined amount or one or more of the blade energies exceed the predetermined damage threshold.