Wind turbine power generating apparatus and method of operating the same

1. A method of operating a wind turbine power generating apparatus including a wind turbine rotor having a wind turbine blade, the method comprising:

a step of obtaining a load applied to the wind turbine blade; and

a step of selecting an operation mode of the wind turbine power generating apparatus on the basis of the load, from among a plurality of operation modes including a normal operation mode and at least one load-suppressing operation mode in which the load applied to the wind turbine blade is smaller than in the normal operation mode,

wherein in the step of selecting the operation mode, one of the at least one load-suppressing mode is selected if the load is equal to or greater than a threshold, and

wherein the threshold of the load is variable in accordance with at least one of a moment Md of the wind turbine rotor about a line in which a rotational plane and a horizontal plane of the wind turbine rotor intersect with each other, or a moment Mq of the wind turbine rotor about a yaw-rotational axis of the wind turbine power generating apparatus.

2. The method of operating a wind turbine power generating apparatus according to claim 1 ,

wherein, in the step of selecting the operation mode, one of the at least one load-suppressing operation mode is selected if at least one of the load or an amplitude of the load is at least a threshold.

3. The method of operating a wind turbine power generating apparatus according to claim 1 ,

wherein the wind turbine power generating apparatus further comprises a nacelle for rotatably supporting the wind turbine rotor,

wherein the method further comprises a step of obtaining an acceleration of the nacelle, and

wherein, in the step of selecting the operation mode, the operation mode is selected on the basis of the acceleration of the nacelle in addition to the load.

4. The method of operating a wind turbine power generating apparatus according to claim 1 ,

wherein, in the at least one load-suppressing operation mode, the load is suppressed more than in the normal operation mode by reducing a rotation speed of the wind turbine rotor or by changing a pitch angle of the wind turbine blade to a feather side as compared to in an operation in the normal operation mode.

5. The method of operating a wind turbine power generating apparatus according to claim 1 ,

wherein the at least one load-suppressing operation mode includes a first load-suppressing operation mode, and a second load-suppressing operation mode in which the load is suppressed more than in the first load-suppressing operation mode by reducing a rotation speed of the wind turbine rotor or by changing a pitch angle of the wind turbine blade to a feather side as compared to in the first load-suppressing operation mode.

6. A method of operating a wind turbine power generating apparatus including a wind turbine rotor having a wind turbine blade, the method comprising:

a step of obtaining a load applied to the wind turbine blade;

a step of selecting an operation mode of the wind turbine power generating apparatus on the basis of the load, from among a plurality of operation modes including a normal operation mode and at least one load-suppressing operation mode in which the load applied to the wind turbine blade is smaller than in the normal operation mode; and

a step of obtaining, on the basis of the load, at least one of a moment Md of the wind turbine rotor about a line in which a rotational plane and a horizontal plane of the wind turbine rotor intersect with each other, or a moment Mq of the wind turbine rotor about a yaw-rotation axis of the wind turbine power generating apparatus,

wherein, in the step of selecting the operation mode, the operation mode is selected on the basis of the at least one of the moment Md or the moment Mq in addition to the load.

7. A wind turbine power generating apparatus, comprising:

a wind turbine rotor having a wind turbine blade;

a load sensor for obtaining a load applied to the wind turbine blade; and

an operation-mode selecting part configured to select an operation mode of the wind turbine power generating apparatus, on the basis of the load obtained by the load sensor, from among a plurality of operation modes including a normal operation mode and at least one load-suppressing operation mode in which the load applied to the wind turbine blade is smaller than in the normal operation mode,

wherein the operation-mode selecting part is configured to select one of the at least one load-suppressing mode if the load is equal to or greater than a threshold, and

wherein the threshold of the load is variable in accordance with at least one of a moment Md of the wind turbine rotor about a line in which a rotational plane and a horizontal plane of the wind turbine rotor intersect with each other, or a moment Mq of the wind turbine rotor about a yaw-rotational axis of the wind turbine power generating apparatus.

8. The wind turbine power generating apparatus according to claim 7 ,

wherein the operation-mode selecting part is configured to select one of the at least one load-suppressing operation mode if at least one of the load or an amplitude of the load is at least a threshold.

9. The wind turbine power generating apparatus according to claim 7 , further comprising: a nacelle for rotatably supporting the wind turbine rotor; and

an acceleration sensor for obtaining an acceleration of the nacelle,

wherein the operation-mode selecting part is configured to select the operation mode on the basis of the acceleration of the nacelle obtained by the acceleration sensor, in addition to the load.

10. The wind turbine power generating apparatus according to claim 7 , further comprising an operation control part for controlling operation of the wind turbine power generating apparatus on the basis of the operation mode,

wherein the operation control part is configured to, in the at least one load-suppressing operation mode, suppress the load more than in the normal operation mode by reducing a rotation speed of the wind turbine rotor or by changing a pitch angle of the wind turbine blade to a feather side as compared to in an operation in the normal operation mode.

11. The wind turbine power generating apparatus according to claim 7 ,

wherein the at least one load-suppressing operation mode includes a first load-suppressing operation mode, and a second load-suppressing operation mode in which the load is suppressed more than in the first load-suppressing operation mode by reducing a rotation speed of the wind turbine rotor or by changing a pitch angle of the wind turbine blade to a feather side as compared to in the first load-suppressing operation mode.

12. A wind turbine power generating apparatus, comprising:

a wind turbine rotor having a wind turbine blade;

a load sensor configured to obtain a load applied to the wind turbine blade;

an operation-mode selecting part configured to select an operation mode of the wind turbine power generating apparatus, on the basis of the load obtained by the load sensor, from among a plurality of operation modes including a normal operation mode and at least one load-suppressing operation mode in which the load applied to the wind turbine blade is smaller than in the normal operation mode; and

a moment calculating part configured to obtain, on the basis of the load, at least one of a moment Md of the wind turbine rotor about a line in which a rotational plane and a horizontal plane of the wind turbine rotor intersect with each other, or a moment Mq of the wind turbine rotor about a yaw-rotation axis of the wind turbine power generating apparatus, and wherein the operation-mode selecting part is configured to select the operation mode on the basis of the at least one of the moment Md or the moment Mq obtained by the moment calculating part, in addition to the load.