Method of calibrating load measurement apparatus, load measurement system of wind turbine blade, and wind turbine

Patent metadata

Field	Value
Publication number	US-10054510-B2
Application number	US-201615140485-A
Country	US
Kind code	B2
Filing date	Apr 28, 2016
Priority date	Sep 11, 2015
Publication date	Aug 21, 2018
Grant date	Aug 21, 2018

Abstract

A method of calibrating a load measurement apparatus for measuring a load on a wind turbine blade on the basis of strain data based on strain of a wind turbine blade includes: a strain-data acquisition step of, during a startup of a wind turbine, obtaining a plurality of the strain data for each of a plurality of conditions among which at least one of an azimuth angle or a pitch angle of the wind turbine blade is different from one another; a theoretical load-value acquisition step of obtaining a theoretical load value applied to the wind turbine blade due to own weight of the wind turbine blade, for each of the plurality of conditions, on the basis of the azimuth angle and the pitch angle of the wind turbine blade in each of the plurality of conditions; and a calibration-parameter calculation step of calculating a calibration parameter representing a relationship between the strain data obtained by the load measurement apparatus and the load on the wind turbine blade, on the basis of a correlation between each of the strain data and the theoretical load value.

First claim

The invention claimed is:

1. A method of calibrating a load measurement apparatus for measuring a load on a wind turbine blade on the basis of strain data based on strain of a wind turbine blade, the method comprising:
a strain-data acquisition step of, during a startup of a wind turbine, providing the load measurement apparatus with a command to obtain a plurality of the strain data for each of a plurality of conditions among which at least one of an azimuth angle or a pitch angle of the wind turbine blade is different from one another;
a theoretical load-value acquisition step of obtaining a theoretical load value applied to the wind turbine blade due to own weight of the wind turbine blade, for each of the plurality of conditions, from a load-value reference table which stores the theoretical load value associated with the azimuth angle and the pitch angle of the wind turbine blade in each of the plurality of conditions; and
a calibration-parameter calculation step of calculating a calibration parameter representing a relationship between the strain data obtained by the load measurement apparatus and the load on the wind turbine blade, on the basis of a correlation between each of the strain data and the theoretical load value.

2. The method of calibrating a load measurement apparatus according to claim 1 , further comprising
a calibration step of calibrating the load measurement apparatus on the basis of at least one of a plurality of calibration parameters calculated on the basis of a plurality of sets of the strain data obtained in the strain-data acquisition step carried out in respective past multiple startups of the wind turbine.

3. The method of calibrating a load measurement apparatus according to claim 2 ,
the calibration step comprises calibrating the load measurement apparatus by using statistic values of two or more of the plurality of calibration parameters.

4. The method of calibrating a load measurement apparatus according to claim 2 ,
wherein the calibration step comprises
calculating a parameter-difference index representing a difference between at least one of the plurality of calibration parameters and a conversion calibration parameter currently used by the load measurement apparatus to convert the strain data into the load, and
updating the conversion calibration parameter on the basis of at least one of the plurality of calibration parameters if the parameter-difference index exceeds an allowable range.

5. The method of calibrating a load measurement apparatus according to claim 4 ,
wherein the parameter-difference index is a difference between a first load value obtained by converting a reference value of the strain data by using the conversion calibration parameter, and a second load value obtained by converting the reference value by using at least one of the plurality of calibration parameters.

6. The method of calibrating a load measurement apparatus according to claim 1 , the method further comprising:
selecting at least one calibration parameter from the plurality of calibration parameters calculated on the basis of a plurality of sets of the strain data obtained in the strain-data acquisition step carried out in respective past multiple startups of the wind turbine, the selected at least one calibration parameter being calculated from the strain data obtained when a wind speed is at most a threshold value or when a rotation speed of a wind turbine rotor is at most a threshold value in the strain-data acquisition step; and
calibrating the load measurement apparatus using the selected at least one calibration parameter only.

7. The method of calibrating a load measurement apparatus according to claim 6 ,
wherein the threshold value of the wind speed is at most 80% of a rated wind speed, or the threshold value of the rotation speed of the wind turbine rotor is at most 50% of a rated rotation speed.

8. The method of calibrating a load measurement apparatus according to claim 1 ,
wherein, in the strain-data acquisition step, when a feather angle of a pitch angle of the wind turbine blade is represented as 0% and a fine angle as 100%, the strain data is obtained while the pitch angle of the wind turbine blade is within a range of from 40 to 60%.

9. The method of calibrating a load measurement apparatus according to claim 1 , wherein, among the plurality of conditions, the pitch angle is the same and the azimuth angle is different from one another.

10. The method of calibrating a load measurement apparatus according to claim 1 , wherein, in the strain-data acquisition step, the plurality of the strain data is obtained for each of the plurality of conditions among which the azimuth angle is different from one another during a standby period which is a part of the startup of the wind turbine, the pitch angle being kept constant at θ w between a full-feather position and a full-fine position in the standby period.

11. A load measurement system for a wind turbine blade, comprising: a load measurement apparatus configured to measure a load on the wind turbine blade of a wind turbine on the basis of strain data based on strain of the wind turbine blade; and a calibration part configured to calibrate the load measurement apparatus, the calibration part comprising:
a strain-data acquisition command part configured to provide the load measurement apparatus with a command to, during a startup of a wind turbine, obtain a plurality of the strain data for each of a plurality of conditions among which at least one of an azimuth angle or a pitch angle of the wind turbine blade is different from one another;
a theoretical load-value acquisition part configured to obtain a theoretical load value applied to the wind turbine blade due to own weight of the wind turbine blade, for each of the plurality of conditions, from a load-value reference table which stores the theoretical load value associated with the azimuth angle and the pitch angle of the wind turbine blade in each of the plurality of conditions; and
a calibration-parameter calculation part configured to calculate a calibration parameter representing a relationship between the strain data obtained by the load measurement apparatus and the load on the wind turbine blade, on the basis of a correlation between each of the strain data and the theoretical load value.

12. The load measurement system for a wind turbine blade according to claim 11 ,
wherein the calibration part is configured to calibrate the load measurement apparatus on the basis of at least one of a plurality of calibration parameters calculated on the basis of a plurality of sets of the strain data obtained on the basis of the command of the strain-data acquisition command part in respective past multiple startups of the wind turbine.

13. The load measurement system for a wind turbine blade according to claim 11 ,
wherein the calibration parameter calculation part is configured to calculate the calibration parameter using only the strain data obtained when a wind speed is at most a threshold value or when a rotation speed of a wind turbine rotor is at most a threshold value, from among the plurality of strain data obtained on the basis of the command of the strain-data acquisition command part.

14. The load measurement system for a wind turbine blade according to claim 11 ,
wherein the load measurement apparatus includes a pair of strain sensors disposed on opposite sides of the wind turbine blade and configured to detect a strain of the wind turbine blade at respective mounting positions of the wind turbine blade, the load measurement apparatus being configured to obtain a difference betwee

Assignees

• Mitsubishi Heavy Ind Ltd

Inventors

• Baba Mitsuya
• Ariki Wakako

Classifications

• F05B2270/17

  to avoid excessive deflection of the blades · CPC title

• F05B2270/331

  Mechanical loads · CPC title

• G01B11/165

  by means of a grating deformed by the object · CPC title

• G01L25/00 Primary

  Testing or calibrating of apparatus for measuring force, torque, work, mechanical power, or mechanical efficiency · CPC title

• F05B2270/332

  Maximum loads or fatigue criteria · CPC title