A wind turbine tower load calibration method and calibration device

Abstract

The present disclosure relates to a wind turbine tower load calibration method and a calibration device. The measurement method comprises: determining the cross section of the detected load of the tower, and determining the first measurement point and the second measurement point arranged at the edge of the cross section and the inner wall of the tower; rotating the nacelle at the upper part of the tower clockwise and counterclockwise for one turn respectively to measure and obtain the first zero value at the first measurement point, the first maximum value and the second zero value at the second measurement point, the second maximum value; when the first measurement point measures the first measurement maximum value, the current measurement value of the second measurement point is measured as the second eccentric zero value; when the second measurement point measures the second measurement maximum value, the current measurement value of the first measurement point is measured as the first eccentric zero value. The present disclosure aims to reduce the error between the theoretical value and the measured load through the calibration method or the use of the calibration device, and ensure the reliability of the measurement result.

Description

Technical Field

[0001] This application relates to the field of fiber optic sensing technology, and in particular to a method and device for calibrating the load on a wind turbine tower. Background Technology

[0002] Fiber optic load sensors are high-precision strain measurement devices based on optical principles. They offer significant advantages such as high sensitivity, resistance to electromagnetic interference (EMI), corrosion resistance, and long-distance transmission, making them widely used in structural health monitoring (SHM) in fields such as civil engineering, aerospace, shipbuilding, and energy equipment. Generally, fiber optic load sensors are based on fiber Bragg gratings (FBGs) or distributed acoustic sensing (DAS) technologies. Because fiber optic sensors use optical signal transmission, they are unaffected by electromagnetic interference (EMI) and possess characteristics such as corrosion resistance, fatigue resistance, and good long-term stability, making them particularly suitable for long-term monitoring of large structures such as wind turbine towers, bridges, and aircraft wings. Furthermore, during wind turbine operation, the tower is subjected to various dynamic loads such as wind loads, turbine vibration, and yaw moment, leading to bending stress in the tower. Traditional strain gauges or accelerometers are susceptible to EMI and have poor long-term stability, making them unsuitable for high-precision, long-term online monitoring. To adapt to long-term monitoring in complex wind farm environments, reliable data support is provided for the structural safety assessment of wind turbine units. Furthermore, to monitor the bending stress generated in the tower, several sensors monitoring the load are installed on the tower. This directly presents two problems: 1) Minimize the number of monitoring sensors; a large number not only increases monitoring costs but may also pose structural risks to the tower. 2) Installation during engineering cannot be perfectly ideal, inevitably resulting in actual installation errors.

[0003] Therefore, existing technologies still need to be improved and enhanced.

[0004] It should be noted that the above introduction to the technical background is only for the purpose of providing a clear and complete explanation of the technical solutions of this application and facilitating understanding by those skilled in the art. It should not be assumed that these technical solutions are known to those skilled in the art simply because they have been described in the background section of this application. Summary of the Invention

[0005] To address one or more of the aforementioned technical problems, such as deviations in actual engineering installations, this disclosure provides a method and apparatus for calibrating the load on a wind turbine tower. The aim is to reduce the error between theoretical values ​​and measured loads and ensure the reliability of measurement results through the calibration method or the use of the calibration apparatus.

[0006] In a first aspect of this disclosure, a method for calibrating the load on a wind turbine tower is proposed. The calibration method includes: determining the cross section of the tower to be tested, and determining a first measurement point and a second measurement point located at the edge of the cross section and on the inner wall of the tower; rotating the nacelle on the upper part of the tower clockwise and counterclockwise one revolution at a time to measure a first zero-point value and a first maximum value at the first measurement point, and a second zero-point value and a second maximum value at the second measurement point; when the first measurement point measures the first maximum value, measuring the current measurement value of the second measurement point as a second eccentric zero-point value; when the second measurement point measures the second maximum value, measuring the current measurement value of the first measurement point as a first eccentric zero-point value; and then determining a corrected first load bending moment and a corrected second load bending moment based on the measured wavelength values ​​of the first and second measurement points.

[0007] Furthermore, in some embodiments, fiber optic load sensors are respectively arranged at the first measurement point and the second measurement point to measure the load at the first measurement point and the second measurement point; the fiber optic load sensors are disposed on the inner wall surface of the tower.

[0008] Furthermore, in some embodiments, determining the first and second measuring points set at the outer edge of the cross section includes: the first line connecting the first measuring point to the central axis of the tower and the second line connecting the second measuring point to the central axis of the tower are nearly orthogonal on the cross section.

[0009] Furthermore, in some embodiments, the determination of the first and second measuring points set at the outer edge of the cross section includes: the first line connecting the first measuring point to the central axis of the tower and the second line connecting the second measuring point to the central axis of the tower form a 90±5 degree angle on the cross section.

[0010] Furthermore, in some embodiments, the above-mentioned rotation of the upper nacelle of the tower in a clockwise and counterclockwise rotation of one revolution each includes: rotating the upper nacelle of the tower clockwise by 365 degrees and then counterclockwise by 365 degrees, or rotating the upper nacelle of the tower counterclockwise by 365 degrees and then clockwise by 365 degrees.

[0011] Further, in some embodiments, obtaining the first zero-bit value and the first maximum value at the first measurement point, and the second zero-bit value and the second maximum value at the second measurement point, includes: obtaining the first positive maximum wavelength value, the first positive minimum wavelength value, the first negative maximum wavelength value, and the first negative minimum wavelength value at the first measurement point, and the second positive maximum wavelength value, the second positive minimum wavelength value, the second negative maximum wavelength value, and the second negative minimum wavelength value at the second measurement point; determining the first zero-bit value as the arithmetic mean of the first positive maximum wavelength value, the first positive minimum wavelength value, the first negative maximum wavelength value, and the first negative minimum wavelength value; determining the first maximum value as the arithmetic mean of the first positive maximum wavelength value and the first negative maximum wavelength value; determining the second zero-bit value as the arithmetic mean of the second positive maximum wavelength value, the second positive minimum wavelength value, the second negative maximum wavelength value, and the second negative minimum wavelength value; and determining the second maximum value as the arithmetic mean of the second positive maximum wavelength value and the second negative maximum wavelength value.

[0012] Furthermore, in some embodiments, the calibration method further includes: determining a first load relationship based on the second zero-point value and the second maximum value; and determining a second load relationship based on the first zero-point value and the first maximum value, wherein the first load relationship is set as follows: Kxx*(λ y_max -λ y_0 )=mg*e ; The second load relationship described above is set as follows: Kyy*(λ x_max -λ x_0 )=mg*e Where Kxx represents the load factor for the first load relationship, Kyy represents the load factor for the second load relationship, and λ y_max Represented as the second maximum value, λ y_0 Represented as the second zero value, λ x_max Let λ be the first maximum value. x_0 The value is represented as the first zero point, m represents the total mass of the upper part of the tower, g represents the gravitational acceleration, and e represents the eccentric distance between the total center of gravity and the center line of the tower.

[0013] Furthermore, in some embodiments, the calibration method further includes: determining a first load bending moment and a second load bending moment based on the measured wavelength values ​​of the first measurement point and the second measurement point, wherein the first load bending moment is set as follows: Mx=Kxx*(λ y -λ y_0) ; The aforementioned second load bending moment is set as follows: My=Kyy*(λ x -λ x_0 ) Where Mx represents the first load bending moment, My represents the second load bending moment, and λ y The wavelength λ is represented by the measured value at the second measurement point. x This is represented by the measured wavelength value at the first measurement point.

[0014] Furthermore, in some embodiments, the calibration method further includes: determining a first cross-influence relationship based on the first zero-point value and the first eccentric zero-point value; and determining a second cross-influence relationship based on the second zero-point value and the second eccentric zero-point value; wherein the first cross-influence relationship is set as follows: λ x_0 -λ x_center =Kxy*mg*e ; The second cross-influence relationship mentioned above is set as follows: λ y_0 -λ y_center =Kyx*mg*e , where λ x_center Represented as the first eccentric zero value, λ y_center The value is represented as the second eccentric zero point, Kxy is represented as the cross-influence coefficient of the first cross-influence relationship, and Kyx is represented as the cross-influence coefficient of the second cross-influence relationship.

[0015] Furthermore, in some embodiments, the determination of the corrected first load bending moment and the corrected second load bending moment based on the measured wavelength values ​​of the first and second measurement points includes: The modified first load bending moment is set as follows: Mx_modified=Kxx*(λ y -λ y_0 -Kyx*My) ; The modified second load bending moment is set as follows: My_modified=Kyy*(λ x -λ x_0 -Kxy*Mx) Where Mx_modified represents the modified first load moment, and My_modified represents the modified second load moment.

[0016] A second aspect of this disclosure provides a wind turbine tower load calibration device, comprising: a measurement point determination unit for determining the cross section of the tower under test load, and determining a first measurement point and a second measurement point located at the edge of the cross section and on the inner wall of the tower; an extreme value / zero point determination unit for rotating the nacelle at the top of the tower clockwise and counterclockwise one revolution to measure a first zero point value and a first maximum value at the first measurement point, and a second zero point value and a second maximum value at the second measurement point; an eccentric zero point determination unit for measuring a second eccentric zero point value when a first maximum value is measured at the first measurement point, and measuring a first eccentric zero point value when a second maximum value is measured at the second measurement point; and a corrected bending moment determination unit for determining a corrected first load bending moment and a corrected second load bending moment based on the measured wavelength values ​​of the first and second measurement points.

[0017] The beneficial effects of this disclosure are as follows: In some embodiments of this disclosure, by setting the cross section of the tower to be tested and determining the first and second measurement points at the edge of the cross section and the inner wall of the tower, only two fiber optic load sensors need to be installed on each cross section of the tower to achieve load monitoring in two orthogonal directions of the tower, thereby saving measurement costs; through actual installation calibration of the tower load measurement, more accurate tower load monitoring is achieved. Attached Figure Description

[0018] The above and other features, advantages and aspects of the embodiments of this disclosure will become more apparent from the accompanying drawings and the following detailed description, wherein: Figure 1 A schematic diagram of the composition structure of a wind turbine generator set according to an embodiment of the present disclosure is shown; Figure 2 A top-view schematic diagram of a wind turbine structure is shown according to an embodiment of the present disclosure; Figure 3 Another schematic diagram of a wind turbine structure from a top view according to an embodiment of the present disclosure is shown; Figure 4 A schematic diagram of an ideally mounted sensor in a tower cross-section according to an embodiment of the present disclosure is shown; Figure 5 A schematic diagram showing the actual installation of a sensor in a tower cross-section according to an embodiment of the present disclosure is shown; Figure 6 A flowchart of a wind turbine tower load calibration method according to an embodiment of the present disclosure is shown; Figure 7A schematic diagram of a wind turbine tower load calibration device according to an embodiment of the present disclosure is shown; and In the various figures, the same or corresponding reference numerals indicate the same or corresponding parts. Detailed Implementation

[0019] Embodiments of this disclosure will now be described in more detail with reference to the accompanying drawings. While some embodiments of this disclosure are shown in the drawings, it should be understood that this disclosure can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of this disclosure. It should be understood that the accompanying drawings and embodiments of this disclosure are for illustrative purposes only and are not intended to limit the scope of protection of this disclosure.

[0020] In the description of embodiments of this disclosure, the term "comprising" and similar terms should be understood as open-ended inclusion, i.e., "including but not limited to". The term "based on" should be understood as "at least partially based on". The term "one embodiment" or "the embodiment" should be understood as "at least one embodiment". The terms "first", "second", etc., may refer to different or the same objects. Other explicit and implicit definitions may also be included below.

[0021] Generally, existing methods for monitoring tower loads in wind turbines are based on the principle that, in low-wind standby mode, the load on the tower primarily comes from the gravity of the nacelle and blades. Therefore, when the nacelle yaws one revolution, the tower load forms a relatively regular sinusoidal signal. The load corresponding to different nacelle azimuth angles is constant. That is, after the wind turbine has been running for a period of time and then stopped, and the wind speed is basically the same as the wind speed at the time of yaw, the tower load value can be calculated based on the nacelle azimuth angle. However, existing technologies generally use a four-point measurement method, requiring the simultaneous installation of four load monitoring devices at 0, 90, 180, and 270 degrees on the tower measurement section (tower sidewall) to compensate for the shortcomings of installing a single load monitoring device. Furthermore, some existing load monitoring methods do not consider the scenario of actual installation rather than ideal installation. That is, in real-world engineering installations, it is not guaranteed that the sensors will be ideally installed in the specified or relative positions. Such non-ideal installations will obviously introduce some deviations in load monitoring, leading to deficiencies or even failure of the monitoring method.

[0022] To address at least one of the aforementioned problems, as well as one or more other potential problems, exemplary embodiments of this disclosure propose a method for calibrating the tower load of a wind turbine. The aim of this calibration method is to reduce the error between theoretical values ​​and measured loads, thereby ensuring the reliability of measurement results.

[0023] Specifically, the following explanation is provided in conjunction with the accompanying drawings. It should be noted that, in order to more clearly illustrate the technical solution of this disclosure, the wind turbine tower structure and sensor arrangement are first explained.

[0024] Figure 1 A schematic diagram of a wind turbine assembly structure according to an embodiment of the present disclosure is shown. In the illustrated embodiment, the lower tower body is shown, which is generally a flat-topped conical structure with a centerline as shown. Further, a nacelle portion is installed on the upper part of the tower, which can be referred to as the upper tower structure (generally including: nacelle, generator, hub, impeller, etc.), where e is the eccentricity of the total mass of the upper tower relative to the center of the tower, m is the total mass of the upper tower structure, and correspondingly, g is the acceleration due to gravity. Further, the illustration includes an example of the installation cross-section of load monitoring sensors in layers A, B, C, and D. It should be understood that this four-layer cross-sectional arrangement is exemplary, and the number of layers can be increased or decreased according to the actual height of the tower to better monitor the tower load. It should also be understood that the fiber optic load sensors should be installed on the inner wall of the tower to minimize environmental impact during daily use.

[0025] It should be noted that, in order to more clearly explain the technical solution of this disclosure, some relevant technologies of the wind turbine tower structure are further explained and described.

[0026] Figure 2 A schematic diagram of a wind turbine structure from a top view according to an embodiment of the present disclosure is shown. In this illustrated embodiment, the upper structure of the tower is shown from a top view (mainly showing the nacelle and hub, omitting the generator, rotor, etc.). It should be noted that this simplification is more conducive to explaining the embodiments of the present disclosure. The diagram shows a schematic of the upper tower structure rotating clockwise along the tower centerline. Similarly, Figure 3 Another schematic diagram of a wind turbine structure from a top view according to an embodiment of the present disclosure is shown. In this illustrated embodiment, a schematic diagram of the upper tower structure rotating counterclockwise along the tower centerline is shown. It should be understood that due to the presence of photoelectric transmission circuits inside the connection between the upper tower structure and the tower, the rotation of the upper tower structure is generally limited to one clockwise rotation (0 degrees - 360 degrees) or one counterclockwise rotation (360 degrees - 0 degrees).

[0027] Figure 4 A schematic diagram of an ideally mounted sensor in a tower cross-section according to an embodiment of the present disclosure is shown. In this illustrated embodiment, a... Figure 1 The diagram illustrates the installation of a load cell in a cross-section of a tower. Two measuring points are orthogonal (90 degrees), with one point located exactly on the x-axis and the other on the y-axis. It should be understood that... Figure 4In the ideal arrangement of two measurement points, however, when installing load sensors (corresponding to the arrangement of measurement points) on site, it is impossible to achieve the most ideal orthogonal position. Figure 5 A schematic diagram showing the actual installation of a sensor in a tower cross-section according to an embodiment of the present disclosure is illustrated. Figure 5 In the diagram, the second measuring point, positioned along the vertical Y-axis, forms an angle β with the Y-axis; correspondingly, the first measuring point, positioned along the horizontal X-axis, forms an angle α with the X-axis. This represents the actual arrangement of the load sensor (as the actual working condition of the measuring points). Clearly, such a non-ideal angular deviation will inevitably introduce data errors into the actual monitoring of the tower load. Therefore, it is necessary to compensate for this deviation caused by the actual installation through calibration methods.

[0028] Figure 6 A flowchart of a wind turbine tower load calibration method according to an embodiment of the present disclosure is shown. In the illustrated embodiment, a wind turbine tower load calibration method 600 is shown, which includes the following steps: Step 610, determining the cross section of the tower under test load, and determining a first measuring point and a second measuring point disposed on the inner wall of the tower at the edge of the cross section. Step 620: Rotate the nacelle at the top of the tower clockwise and counterclockwise one revolution each to measure the first zero-point value λx_0 and the first maximum value λx_max at the first measurement point, and the second zero-point value λy_0 and the second maximum value λy_max at the second measurement point; Step 630: When the first measurement point obtains the first maximum value (λx reaches its maximum value), measure the current measurement value of the second measurement point as the second eccentric zero-point value λy_center; When the second measurement point obtains the second maximum value (λy reaches its maximum value), measure the current measurement value of the first measurement point as the first eccentric zero-point value λx_center; Step 640: Determine the corrected first load bending moment Mx_modified and the corrected second load bending moment My_modified based on the measured wavelength values ​​(i.e., λx and λy) of the first and second measurement points.

[0029] Further, in some embodiments, in step 610, fiber optic load sensors are respectively arranged at the first and second measurement points to measure the load at the first and second measurement points; the fiber optic load sensors are disposed on the inner wall surface of the tower. Specifically, the first line connecting the first measurement point to the central axis of the tower and the second line connecting the second measurement point to the central axis of the tower are nearly orthogonal in the cross-section. Preferably, the first line connecting the first measurement point to the central axis of the tower and the second line connecting the second measurement point to the central axis of the tower form a 90±5 degree angle in the cross-section. It should be understood that if this angle is too large, exceeding 90 degrees, it may cause the calibration process to fail. Obviously, ideally, it should be as follows... Figure 4 The arrangement shown is ideal. However, in reality, such an ideal arrangement is almost non-existent; the actual arrangement in engineering projects should be as follows: Figure 5 The arrangement should be as described above, but generally speaking, it should be ensured that the first line connecting the first measuring point to the central axis of the tower and the second line connecting the second measuring point to the central axis of the tower form a 90±5 degree angle on the cross section.

[0030] Furthermore, in some embodiments, in step 620, rotating the nacelle on the upper part of the tower clockwise and counterclockwise by one revolution each means: rotating the nacelle on the upper part of the tower clockwise by 365 degrees and then counterclockwise by 365 degrees (one revolution clockwise, then one revolution counterclockwise), or rotating the nacelle on the upper part of the tower counterclockwise by 365 degrees and then clockwise by 365 degrees (one revolution counterclockwise, then one revolution clockwise). It should be understood that the reason for not rotating more times is generally due to the numerous wiring connections between the upper part of the tower and the tower itself; excessive rotation could lead to wiring problems and other issues. It should also be understood that the above wind turbine tower load calibration method should be performed under conditions where the ambient wind speed is less than 5 m / s; otherwise, the calibration will be invalid.

[0031] Further, in some embodiments, in step 620, the so-called measurement of the first zero-point value λx_0 and the first maximum value λx_max at the first measurement point and the second zero-point value λy_0 and the second maximum value λy_max at the second measurement point means obtaining the first positive maximum wavelength value λx_max_p, the first positive minimum wavelength value λx_min_p, the first negative maximum wavelength value λx_max_n, and the first negative minimum wavelength value λx_min_n at the first measurement point, and the second positive maximum wavelength value λy_max_p, the second positive minimum wavelength value λy_min_p, the second negative maximum wavelength value λy_max_n, and the second negative minimum wavelength value λy_min_n at the second measurement point; determining the first zero-point value λx_0 as the arithmetic mean of the first positive maximum wavelength value λx_max_p, the first positive minimum wavelength value λx_min_p, the first negative maximum wavelength value λx_max_n, and the first negative minimum wavelength value λx_min_n, i.e., λx_0 = ( λx_max_p + λx_min_p + λx_max_n + λx_min_n) / 4; The first maximum value λx_max is determined to be the arithmetic mean of the first positive maximum wavelength value λx_max_p and the first negative maximum wavelength value λx_max_n, i.e., λx_max = (λx_max_p + λx_max_n) / 2; The second zero-point value λy_0 is determined to be the second positive maximum wavelength value λy_max_p and the second positive minimum wavelength value λy_min_p. The arithmetic mean of the second reflected maximum wavelength value λy_max_n and the second reflected minimum wavelength value λy_min_p is λy_0 = (λy_max_p + λy_min_p + λy_max_n + λy_min_n) / 4; the second maximum value λy_max is determined to be the arithmetic mean of the second positive maximum wavelength value λy_max_p and the second reflected maximum wavelength value λy_max_n, i.e., λy_max = (λy_max_p + λy_max_n) / 2. It should be understood that when rotating clockwise for one full cycle (360 degrees), the first positive maximum wavelength value λx_max_p, the first positive minimum wavelength value λx_min_p, the second positive maximum wavelength value λy_max_p, and the second positive minimum wavelength value λy_min_p are obtained; while when rotating counterclockwise for one full cycle (360 degrees), the first reverse maximum wavelength value λx_max_n, the first reverse minimum wavelength value λx_min_n, the second reverse maximum wavelength value λy_max_n, and the second reverse minimum wavelength value λy_min_n are obtained.Ideally, the first positive maximum wavelength value λx_max_p, the first positive minimum wavelength value λx_min_p, and the second positive maximum wavelength value λy_max_p and the second positive minimum wavelength value λy_min_p during forward rotation should correspond one-to-one with the corresponding first negative maximum wavelength value λx_max_n, the first negative minimum wavelength value λx_min_n, and the second negative maximum wavelength value λy_max_n and the second negative minimum wavelength value λy_min_n during reverse rotation. However, in engineering practice, these values ​​are not always perfectly equal and may have slight deviations. In this calibration scheme, it is necessary to control the ambient wind speed to be less than 5 m / s and other temperature factors to ensure that the numerical deviation is less than 3%. Otherwise, the calibration measurement data should be discarded, and the calibration work in this embodiment should be carried out when the wind speed (less than 5 m / s) and temperature (closer to room temperature) are more suitable. It should be understood that wind speed has the greatest impact on calibration, and usually only wind speed needs to be considered. In other words, to ensure the effectiveness of this calibration method, the deviation between the two maximum values ​​should be within 3%, and the deviation between the two minimum values ​​should also be within 3%.

[0032] Further, in some embodiments, the calibration method 600 further includes: step 622 (between step 620 and step 630), determining the first load relationship (load coefficient) Kxx based on the second zero-point value λy_0 and the second maximum value λy_max; and determining the second load relationship (load coefficient) Kyy based on the first zero-point value λx_0 and the first maximum value λx_max, wherein the first load relationship (load coefficient) Kxx is set as follows: Kxx*(λy_max-λy_0)=mg*e; where e is the eccentric distance of the total mass of the upper part of the tower relative to the center of the tower, m is the total mass of the upper structure of the tower, and g is the acceleration due to gravity.

[0033] The second load relationship described above is set as follows: Kyy*(λx_max-λx_0)=mg*e; where e is the eccentric distance of the total mass of the upper part of the tower relative to the center of the tower, m is the total mass of the upper structure of the tower, and g is the acceleration due to gravity.

[0034] Furthermore, in some embodiments, the calibration method 600 further includes: step 624 (between step 620 and step 630, but after step 622), determining the first load bending moment Mx and the second load bending moment My based on the measured wavelength value λx of the first measurement point and the measured wavelength value λy of the second measurement point, wherein the first load bending moment Mx is set as follows: Mx = Kxx*(λy - λy_0); The second load bending moment My is set as follows: My = Kyy*(λx - λx_0).

[0035] Further, in some embodiments, the calibration method 600 further includes: step 632 (between step 630 and step 640), determining a first cross-influence relationship (cross-influence coefficient) Kxy based on the first zero-point value λx_0 and the first eccentric zero-point value λx_center; and determining a second cross-influence relationship (cross-influence coefficient) Kyx based on the second zero-point value λy_0 and the second eccentric zero-point value λy_center; wherein the first cross-influence relationship (cross-influence coefficient) Kyx is set as follows: λx_0-λx_center=Kxy*mg*e; where e is the eccentricity of the total mass of the upper part of the tower relative to the center of the tower, m is the total mass of the upper structure of the tower, and g is the acceleration due to gravity. The cross-influence coefficient Kyx of the second cross-influence relationship mentioned above is set as follows: λy_0-λy_center=Kyx*mg*e; where e is the eccentric distance of the total mass of the upper part of the tower relative to the center of the tower, m is the total mass of the upper structure of the tower, and g is the acceleration due to gravity.

[0036] Furthermore, in some embodiments, in the above calibration method 600: step 640 specifically involves determining, based on the measured wavelength values ​​(i.e., λx and λy) of the first and second measurement points, that the modified first load bending moment Mx_modified is set as follows: Mx_modified=Kxx*(λy-λy_0-Kyx*My); The modified second load moment My_modified is set as follows: My_modified=Kyy*(λx-λx_0-Kxy*Mx).

[0037] It should also be understood that, as illustrated in the embodiments of this disclosure, the direction of the first measuring point is generally set to the x-direction, and the direction of the second measuring point is set to the y-direction, such as... Figure 4-5 As shown in the diagram.

[0038] Figure 6A schematic diagram of a wind turbine tower load calibration device according to an embodiment of the present disclosure is shown. In the illustrated embodiment, a wind turbine tower load calibration device 700 is shown, comprising: a measurement point determination unit 710, used to determine the cross-section of the tower under test load, and to determine a first measurement point and a second measurement point set at the edge of the cross-section; an extreme value / zero point determination unit 720, used to rotate the nacelle on the upper part of the tower clockwise and counterclockwise one revolution each to measure a first zero point value and a first maximum value at the first measurement point, and a second zero point value and a second maximum value at the second measurement point; an eccentric zero point determination unit 730, used to measure a second eccentric zero point value when a first maximum value is measured at the first measurement point, and to measure a first eccentric zero point value when a second maximum value is measured at the second measurement point; and a corrected bending moment determination unit 740, used to determine a corrected first load bending moment and a corrected second load bending moment based on the measured wavelength values ​​of the first and second measurement points.

[0039] The various embodiments of this disclosure have been described above. These descriptions are exemplary and not exhaustive, nor are they limited to the disclosed embodiments. Many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the described embodiments. The terminology used herein is chosen to best explain the principles, practical application, or technical improvements to the embodiments in the market, or to enable others skilled in the art to understand the embodiments disclosed herein.

[0040] The above description is merely an optional embodiment of this disclosure and is not intended to limit this disclosure. Various modifications and variations can be made to this disclosure by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the scope of protection of this disclosure.

Claims

1. A method for calibrating the load on a wind turbine tower, characterized in that, include: Determine the cross section of the tower under the load to be detected, and determine the first and second measuring points located at the edge of the cross section and on the inner wall of the tower. The nacelle at the top of the tower is rotated clockwise and counterclockwise one revolution each to measure the first zero point value and the first maximum value at the first measurement point, and the second zero point value and the second maximum value at the second measurement point. When the first measurement point obtains the first maximum measurement value, the current measurement value of the second measurement point is obtained as the second eccentric zero value; When the second measurement point obtains the second maximum value, the current measurement value of the first measurement point is obtained as the first eccentric zero value; Then, the corrected first load bending moment and the corrected second load bending moment are determined based on the measured wavelength values ​​of the first and second measurement points.

2. The wind turbine tower load calibration method according to claim 1, characterized in that, The first measurement point and the second measurement point are respectively equipped with fiber optic load sensors to measure the load at the first measurement point and the second measurement point.

3. The wind turbine tower load calibration method according to claim 1, characterized in that, The determination of the first and second measuring points set at the outer edge of the cross-section includes: The first line connecting the first measuring point to the central axis of the tower and the second line connecting the second measuring point to the central axis of the tower are nearly orthogonal on the cross section.

4. The wind turbine tower load calibration method according to claim 1, characterized in that, The determination of the first and second measuring points set at the outer edge of the cross-section includes: The first line connecting the first measuring point to the central axis of the tower and the second line connecting the second measuring point to the central axis of the tower form a 90±5 degree angle on the cross section.

5. The wind turbine tower load calibration method according to claim 1, characterized in that, The step of rotating the upper part of the tower nacelle clockwise and counterclockwise one revolution each includes: The nacelle at the top of the tower is rotated 365 degrees clockwise and then 365 degrees counterclockwise, or the nacelle at the top of the tower is rotated 365 degrees counterclockwise and then 365 degrees clockwise.

6. The wind turbine tower load calibration method according to claim 1, characterized in that, Obtaining the first zero-point value and the first maximum value at the first measurement point, and the second zero-point value and the second maximum value at the second measurement point, includes: Obtain the first positive maximum wavelength value, the first positive minimum wavelength value, the first negative maximum wavelength value, and the first negative minimum wavelength value at the first measurement point, and the second positive maximum wavelength value, the second positive minimum wavelength value, the second negative maximum wavelength value, and the second negative minimum wavelength value at the second measurement point; The first zero-bit value is determined to be the arithmetic mean of the first positive maximum wavelength value, the first positive minimum wavelength value, the first negative maximum wavelength value, and the first negative minimum wavelength value. The first maximum value is determined to be the arithmetic mean of the first positive maximum wavelength value and the first negative maximum wavelength value; The second zero-bit value is determined to be the arithmetic mean of the second positive maximum wavelength value, the second positive minimum wavelength value, the second negative maximum wavelength value, and the second negative minimum wavelength value; The second maximum value is determined to be the arithmetic mean of the second positive maximum wavelength value and the second negative maximum wavelength value.

7. The wind turbine tower load calibration method according to claim 1, characterized in that, Also includes: The first load relationship is determined based on the second zero value and the second maximum value; and the second load relationship is determined based on the first zero value and the first maximum value. The first load relationship is set as follows: Kxx*(λ y_max -l y_0 )=mg*e; The second load relationship is set as follows: Kyy*(λ x_max -l x_0 )=mg*e; Where Kxx represents the load factor for the first load relationship, Kyy represents the load factor for the second load relationship, and λ y_max Represented as the second maximum value, λ y_0 Represented as the second zero value, λ x_max Let λ be the first maximum value. x_0 The value is represented as the first zero point, m represents the total mass of the upper part of the tower, g represents the gravitational acceleration, and e represents the eccentric distance between the total center of gravity and the center line of the tower.

8. The wind turbine tower load calibration method according to claim 7, characterized in that, Also includes: The first load bending moment and the second load bending moment are determined based on the measured wavelength values ​​of the first and second measurement points, wherein, The first load bending moment is set as follows: Mx=Kxx*(λ y -l y_0 ); The second load bending moment is set as follows: My=Kyy*(λ x -l x_0 ); Where Mx represents the first load bending moment, My represents the second load bending moment, and λ y The wavelength λ is represented by the measured value at the second measurement point. x This is represented by the measured wavelength value at the first measurement point.

9. The wind turbine tower load calibration method according to claim 8, characterized in that, Also includes: A first cross-influence relationship is determined based on the first zero value and the first eccentric zero value; and a second cross-influence relationship is determined based on the second zero value and the second eccentric zero value. The first cross-influence relationship is set as follows: l x_0 -l x_center =Kxy*mg*e; The second cross-influence relationship is set as follows: l y_0 -l y_center =Kyx*mg*e; Where, λ x_center Represented as the first eccentricity zero value, λ y_center The value is represented as the second eccentric zero point, Kxy is represented as the cross-influence coefficient of the first cross-influence relationship, and Kyx is represented as the cross-influence coefficient of the second cross-influence relationship.

10. The wind turbine tower load calibration method according to claim 9, characterized in that, The step of determining the corrected first load bending moment and the corrected second load bending moment based on the measured wavelength values ​​of the first and second measurement points includes: The modified first load bending moment is set as follows: Mx_modified=Kxx*(λ y -λ y_0 -Kyx*My); The modified second load bending moment is set as follows: My_modified=Kyy*(λ x -λ x_0 -Kxy*Mx), Where Mx_modified represents the modified first load bending moment, and My_modified represents the modified second load bending moment.

11. A wind turbine tower load calibration device, characterized in that, include: The measurement point determination unit is used to determine the cross section of the tower under the load being tested, and to determine the first measurement point and the second measurement point set at the edge of the cross section and on the inner wall of the tower. The extreme value zero point determination unit is used to rotate the nacelle at the top of the tower clockwise and counterclockwise one revolution each to measure and obtain the first zero point value and the first maximum value at the first measurement point, and the second zero point value and the second maximum value at the second measurement point. An eccentric zero-position determination unit is used to measure and obtain the current measurement value of the second measurement point as a second eccentric zero-position value when the first measurement point measures and obtains the first measurement maximum value; When the second maximum value is obtained at the second measurement point, the current measurement value at the first measurement point is obtained as the first eccentric zero value. The corrected bending moment determination unit is used to determine the corrected first load bending moment and the corrected second load bending moment based on the measured wavelength values ​​of the first measurement point and the second measurement point.

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