Devices and methods for determining deflection of rotor blades of a wind turbine

Patent metadata

Field	Value
Publication number	US-11614076-B2
Application number	US-202117510702-A
Country	US
Kind code	B2
Filing date	Oct 26, 2021
Priority date	Oct 27, 2020
Publication date	Mar 28, 2023
Grant date	Mar 28, 2023

Abstract

The present disclosure relates to methods and systems for measuring deflection of blades of a wind turbine. Examples include a light emitting and collection device mounted to the nacelle and configured to emit light in a direction within a substantially vertical plane. Examples include a method for operating a wind turbine including emitting light above a hub, receiving the light when reflected by a blade of the wind turbine, and, if the level of blade deflection is above a threshold, reducing blade loading of the blade before the blade reaches a vertically downward position. Examples include a method for monitoring deflection of a rotor blade of a wind turbine comprising emitting a light sheet, collecting reflections of the emitted light, and determining deflection of the rotor blade by determining a time during which the blade reflects the emitted light sheet.

First claim

The invention claimed is:

1. A method for operating a wind turbine having a first light emitting and collecting device mounted to a nacelle, the method comprising:
emitting light in a form of a light sheet above a hub of the wind turbine with the first light and collecting emitting device;
with the first light emitting and collecting device, receiving the light reflected by a blade of the wind turbine;
based on the received reflected light, determining that a level of blade deflection is above a threshold based on an amount of time the blade interferes with and reflects light from the light sheet exceeding a threshold time limit; and
reducing blade loading of the blade before the blade reaches a vertically downward position.

2. The method of claim 1 , wherein the step of reducing blade loading includes at least one of: reducing a rotor speed, pitching of one or more of the blades, and activating aerodynamic actuators.

3. The method of claim 1 wherein the step of emitting light comprises emitting the light sheet vertically above the hub.

4. The method of claim 1 wherein the step of emitting light comprises emitting the light sheet in an upwards direction from the nacelle.

5. The method according to claim 1 , wherein the emitted light is in a region of an electromagnetic spectrum different than a visible region of the electromagnetic spectrum.

6. The method according to claim 1 , wherein the first light emitting and collecting device is configured to measure a distance between the first light emitting and collecting device and a position of reflection of the light from the blade.

7. A method for monitoring deflection of a rotor blade of a wind turbine wherein a first light emitting and collecting device is mounted to the nacelle of the wind turbine, the method comprising:
emitting a light sheet with the first, light emitting and collecting device in a vertically upwards direction from the nacelle;
collecting reflections of the emitted light from the rotor blade with the first light and emitting and collecting device; and
determining deflection of the rotor blade above a threshold value based on a time during which the blade reflects the emitted light sheet.

8. The method according to claim 7 , wherein the wind turbine further comprises a positioning sensor attached to the nacelle and the method further comprises determining one or both of a position and an orientation of the nacelle.

9. The method according to claim 7 , wherein the first light emitting and collecting device is rotatably mounted to the nacelle in such a way that light is emitted within a substantially vertical plane when the nacelle oscillates.

10. The method according to claim 7 , wherein the wind turbine comprises an additional light emitting and collecting device mounted to the nacelle and the step of determining deflection of the rotor blade includes collecting reflections of the emitted light of the first and additional light emitting and collecting devices.

11. The method according to claim 7 , wherein determining a time during which the blade reflects the emitted light sheet, includes measuring a light intensity of light received by the first light emitting and collecting device.

12. A wind turbine, comprising:
a tower;
a nacelle on top of the tower;
a rotor hub with one or more rotor blades rotatably mounted to the nacelle;
a first light emitting and collecting device mounted to the nacelle;
wherein the first light emitting and collecting device is configured to emit light in a form of a light sheet in an upwards direction from the nacelle and to collect a reflection of the emitted light by one of the rotor blades; and
wherein the first light emitting and collecting device is mounted to the nacelle at a horizontal distance of the tower such that a tip of a blade is detected before or when it exceeds a blade deflection limit that is based on an amount of time the rotor blade interferes with and reflects light from the light sheet.

13. The wind turbine according to claim 12 , wherein the first light emitting and collecting device is configured to emit light in a vertical direction.

14. The wind turbine according to claim 12 , further comprising a processor configured to measure a time during which the emitted light is reflected by the blade.

15. The wind turbine according to claim 12 , wherein one or more of the rotor blades include reflective paint at their tips.

16. The wind turbine according to claim 12 , wherein:
the first light emitting and collecting device is rotatably mounted in such a way that light is emitted in a direction within a substantially vertical plane when the nacelle oscillates.

17. The wind turbine according to claim 12 , wherein the wind turbine comprises an additional light emitting and collecting device mounted to the nacelle on a same side of the nacelle as the first light emitting and collecting device.

Assignees

• General Electric Renovables Espana Sl

Inventors

• Herrig Andreas
• Canal Vila Marc

Classifications

• F03D17/003

  characterised by using optical devices, e.g. lidar or cameras · CPC title

• F03D17/022

  for monitoring displacement · CPC title

• F03D17/028 Primary

  Blades · CPC title

• F05B2270/821

  Displacement measuring means, e.g. inductive · CPC title

• F05B2270/804

  Optical devices · CPC title