A wind turbine load measuring device

Abstract

The present invention discloses a wind turbine load measuring device, comprising a cantilever rod and a longitudinal displacement detection head arranged in the length direction of the cantilever rod, wherein the fixed end of the cantilever rod is arranged on a cantilever mounting seat, and the suspended end is provided with a longitudinal reference surface, the longitudinal displacement detection head is fixed on the detection head mounting seat, and a measuring gap is provided between the detection end and the longitudinal reference surface on the cantilever rod, the cantilever mounting seat and the detection head mounting seat are both fixed on the load detection surface of the wind turbine, and an installation positioning device is further provided between the cantilever mounting seat and the detection head mounting seat. The wind turbine load measuring device of the present invention has the advantages of simple installation, convenient maintenance and high accuracy of measurement results, can greatly improve the safety and reliability of wind turbine operation, and has high practical value.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine mechanical load measurement, and in particular to a wind turbine load measurement device. Background Art

[0002] If a wind turbine tower or blade is subjected to continuous alternating loads and the load exceeds its corresponding fatigue limit, fatigue failure and subsequent fracture will occur. Therefore, wind turbine load testing is a critical step in turbine development. Its importance lies in two aspects: first, it can improve the reliability of the turbine throughout its life cycle; second, through the implementation of digital testing, it can optimize turbine design, further reduce turbine development costs, and provide technical support for applications in complex terrain. According to the standard GB / T37257-2018 / IEC 61400-13:2015, wind turbine load testing mainly includes tower load and blade load measurements. Typically, strain gauges are installed in locations such as the tower, the top of the tower, and the blade root, and a full-bridge is assembled to collect load signals and measure the strain in the test area.

[0003] Using strain gauges to measure wind turbine loads has both advantages and disadvantages. The advantage is that the strain gauges are small and easy to carry, and they are a contact-type force measurement. However, the disadvantages are also very obvious. The main disadvantages are: 1. The installation is cumbersome. The installation of a set of strain gauges involves many steps such as point selection, grinding, marking, pasting, and welding. Any carelessness in the above steps will have a certain impact on the load measurement results. 2. Maintenance is not easy. After the strain gauge is installed, it is usually covered with moisture-proof glue, fireproof mud and tin foil tape in sequence. If the strain gauge needs to be replaced later, all coverings on its surface need to be removed. This process is time-consuming and labor-intensive. 3. The strain measurement area at the strain gauge measuring point is small. When loaded, it cannot be guaranteed that the measurement area will produce a corresponding deformation. There is a certain degree of uncertainty, which causes deviations in the measurement results. A Chinese patent document with publication number CN212228366U, published on December 25, 2020, discloses a wind turbine load testing device; it includes a control device, an uninterruptible power supply, three groups of first strain gauges, three groups of second strain gauges, and three groups of third strain gauges. The control device and uninterruptible power supply are installed on the hub, and each group of the first strain gauges is respectively installed at the bottom, middle, and top of the outer wall of the blade. Each group of the second strain gauges is respectively installed at the bottom, middle, and top of the inner wall of the blade. Each group of the third strain gauges is respectively installed at the bottom, middle, and top of the inner wall of the blade. By arranging the first, second, and third strain gauges, the device can monitor the blade load status in real time, provide early warning of fault signs before a major accident occurs, and guide inspection personnel to replace and repair the blades to avoid the occurrence of major faults. However, the device uses strain gauges to measure the load of wind turbines, which has the problems of cumbersome installation and difficult maintenance. The strain measurement area of ​​the strain gauge measuring point is small, and when loaded, it cannot ensure that the measurement area will produce corresponding deformation, resulting in large deviations in the measurement results. Summary of the Invention

[0004] The purpose of the present invention is to solve the problems of the existing wind turbine load measurement device, which is complicated to install and difficult to maintain, and the strain measurement area of ​​the strain gauge measuring point is small, and it cannot ensure that the measurement area produces a corresponding deformation when loaded, thereby causing a large deviation in the measurement results. The present invention provides a wind turbine load measurement device with the advantages of simple installation, convenient maintenance and high measurement accuracy.

[0005] The technical solution adopted by the present invention to solve the above-mentioned technical problems is a wind turbine load measuring device, comprising a cantilever rod and a longitudinal displacement detection head arranged in the length direction of the cantilever rod, the fixed end of the cantilever rod is arranged on the cantilever mounting seat, the suspended end of the cantilever rod is provided with a longitudinal reference surface, the longitudinal displacement detection head is fixed on the detection head mounting seat, the longitudinal displacement detection head is close to the suspended end of the cantilever rod and a measuring gap is provided between the detection end of the longitudinal displacement detection head and the longitudinal reference surface on the cantilever rod, the cantilever mounting seat and the detection head mounting seat are both fixed on the load detection surface of the wind turbine and the cantilever rod is parallel to the load detection surface, and an installation positioning device is also provided between the cantilever mounting seat and the detection head mounting seat.

[0006] The wind turbine load measuring device of the present invention includes a longitudinal displacement detection head and a cantilever rod. The longitudinal displacement detection head is fixed on the detection head mounting seat, and the fixed end of the cantilever rod is fixed on the cantilever mounting seat. The detection head mounting seat and the cantilever mounting seat are both installed on the load detection surface that needs to be measured (usually in the tower, the tower top, the blade root, etc.). The cantilever rod is arranged horizontally and is located on the same axis as the longitudinal displacement detection head. A small measuring gap is provided between the detection end of the longitudinal displacement detection head and the suspended end of the cantilever rod.

[0007] The measurement principle of the present invention is to convert strain measurement into displacement measurement, which greatly improves the measurement accuracy and makes the measurement results more accurate and reliable. During measurement, the load measuring device is installed on the inner wall (load detection surface), and the original distance from the fixed end of the cantilever rod (the end connected to the cantilever mounting seat) to the end of the longitudinal displacement detection head with the signal line is set as L, and there is a small gap between the detection end of the longitudinal displacement detection head and the longitudinal reference plane on the cantilever rod, which is recorded as l. When the load detection surface is deformed by the alternating load, the size of the small gap l changes, and △l / L reflects the strain generated when the installation area of ​​the load measuring device is loaded. Since the load measuring device of the present invention introduces a cantilever rod system with a longer span, the span of the measurement area is large compared to the strain gauge, so it can minimize the impact of the uncertainty of the deformation of the measurement area in the existing technology on the measurement, thereby greatly improving the accuracy of the measurement. Taking into account that after the detection head mounting seat and the cantilever mounting seat are fixed to the load detection surface, the strain of the load detection surface when it is loaded may be affected (that is, the deformation of the load detection surface fixed by the detection head mounting seat and the cantilever mounting seat may be reduced accordingly), the original distance L here can be corrected according to the actual situation to improve the accuracy of the measurement. In addition, in terms of installation and maintenance, the load measuring device of the present invention has a simple structure and is easy to install. It is only necessary to fix the detection head mounting seat and the cantilever mounting seat on the load detection surface (blade or tower inner wall) respectively. In addition, if the load measuring device needs to be tested, calibrated or replaced later, it is only necessary to remove the longitudinal displacement detection head part thereof as a whole, and the other components can remain unchanged. In this way, the present invention solves the problems of the existing wind turbine load measuring device, which has the advantages of simple installation, easy maintenance and high measurement result accuracy.

[0008] Preferably, the installation and positioning device includes a lifting lug and a positioning rod symmetrically arranged on the left and right sides of the cantilever mounting seat and the detection head mounting seat, wherein the lifting lug is provided with a positioning hole, and the positioning rod is inserted into the positioning hole. The positioning rods on both sides are parallel to the cantilever rod and are on the same plane as the cantilever rod, and the lifting lug is also provided with a set screw for fixing the positioning rod; the longitudinal displacement detection head is provided with a photoelectric ranging module and a temperature measurement module. The installation and positioning device can ensure the relative position between the cantilever mounting seat and the detection head mounting seat is accurate, so that the installation error during installation is minimized, thereby improving the measurement accuracy. When the load measuring device is installed, the positioning rod is inserted into the lifting lugs on the detection head mounting seat and the cantilever mounting seat and fixed by a set screw, thereby limiting the freedom of movement of the two, and avoiding the longitudinal displacement detection head and the cantilever rod from tilting or misaligning their axes in the horizontal or vertical direction during the installation process. After the load measuring device is installed, the two positioning rods are removed to avoid affecting the displacement measurement.

[0009] The longitudinal displacement detection head of this solution uses a photoelectric ranging module and is equipped with a temperature measurement module. During measurement, the photoelectric ranging module emits infrared light and senses the infrared light reflected from the longitudinal reference surface on the cantilever rod. The temperature measurement module can directly measure the ambient temperature. When the load detection surface is deformed by the alternating load, the size of the small gap l changes. At the same time, the intensity of the infrared light reflected by the longitudinal displacement detection head also changes. This intensity change signal is transmitted via a signal line to the microcontroller inside the load measurement device. The microcontroller then converts the actual displacement change △l based on the real-time temperature measured by the temperature measurement module and the thermal expansion coefficient of the cantilever rod material. Finally, the microcontroller calculates the strain generated by the load in the load measurement device installation area from △l / L, further improving measurement accuracy.

[0010] Preferably, the detection head mounting seat includes a base plate and a detection head mounting plate vertically arranged on the base plate, the lifting ears are arranged at the left and right ends of the detection head mounting plate, the detection head mounting plate is provided with screw holes, the longitudinal displacement detection head is screwed to the detection head mounting plate, a fastening nut is provided between the longitudinal displacement detection head and the detection head mounting plate, the bottom surfaces of the detection head mounting seat and the cantilever mounting seat are provided with multiple groups of trapezoidal grooves, and the detection head mounting seat and the cantilever mounting seat are both bonded to the load detection surface of the wind turbine by glue. The detection head mounting seat and the cantilever mounting seat of this solution are both bonded to the load detection surface of the wind turbine by glue, which can facilitate the installation and maintenance (disassembly) of the load measuring device. During bonding, the installation positioning device is used to fix the position of the detection head mounting seat and the cantilever mounting seat to ensure installation accuracy.

[0011] Preferably, the cantilever rod is cylindrical and made of a chromium alloy with a low coefficient of thermal expansion. One end of the cantilever rod is threaded, and the cantilever mounting seat is provided with a screw hole. The cantilever rod and the cantilever mounting seat are threadedly connected. A longitudinal reference surface provided at the free end of the cantilever rod is circular, with a diameter greater than the diameter of the cantilever rod, and the longitudinal reference surface is flat. Using a chromium alloy with a low coefficient of thermal expansion for the cantilever rod can reduce measurement errors caused by thermal expansion and contraction of the cantilever rod.

[0012] As another preferred embodiment, the load measuring device also includes a lateral displacement detection head and a vertical displacement detection head. The detection head mounting seat is a horizontally placed rectangular box-shaped body. The suspended end of the cantilever rod is located in the box-shaped body. The bottom of the box-shaped body and the two adjacent side walls are provided with screw holes. The longitudinal displacement detection head is screwed to the bottom of the box-shaped body. The lateral displacement detection head and the vertical displacement detection head are respectively screwed to the two adjacent side walls of the box-shaped body. A fastening nut is provided between the detection head and the detection head mounting seat. The suspended end of the cantilever rod is also provided with a lateral reference plane corresponding to the lateral displacement detection head and a vertical reference plane corresponding to the vertical displacement detection head. There is a gap between the detection end of the lateral displacement detection head and the lateral reference plane, and between the detection end of the vertical displacement detection head and the vertical reference plane. In addition to the longitudinal (X-direction) displacement detection of the aforementioned scheme, this scheme also detects the lateral (Y-direction) and vertical (Z-direction) displacement of the suspended end of the cantilever rod. In this way, based on the displacement data in three directions, a more detailed and accurate judgment can be made on the deformation of the measured area and corresponding countermeasures can be taken, thereby improving the safety and reliability of the wind turbine operation.

[0013] Preferably, the cantilever rod is cylindrical and made of a chromium alloy with a low thermal expansion coefficient. One end of the cantilever rod is provided with a thread, and the cantilever mounting seat is provided with a screw hole. The cantilever rod and the cantilever mounting seat are screwed together. The suspended end of the cantilever rod is provided with a rectangular block. The end surface of the rectangular block constitutes a longitudinal reference plane corresponding to the longitudinal displacement detection head; the side surface of the rectangular block constitutes a transverse reference plane and a vertical reference plane corresponding to the transverse displacement detection head and the vertical displacement detection head; the longitudinal reference plane, transverse reference plane, and vertical reference plane are all planes; and the transverse displacement detection head and the vertical displacement detection head are both provided with a photoelectric ranging module. This solution places a cubic block structure at the suspended end of the cantilever rod, using three mutually perpendicular planes of the cube as corresponding reference planes to complete displacement detection in three directions.

[0014] Preferably, the lifting ears are arranged on the left and right side walls of the detection head mounting seat, and multiple sets of trapezoidal grooves are provided on the side wall of the detection head mounting seat opposite to the load detection surface. The detection head mounting seat is glued to the load detection surface of the wind turbine.

[0015] Preferably, the wind turbine load measurement device further comprises a protective housing, a housing mounting seat being provided on the load detection surface, a screw being fixed to the housing mounting seat, the protective housing being fixed to the load detection surface via the screw, and a cable hole being provided on the protective housing for passing a signal line of the detection head. The protective housing serves to cover and protect the displacement detection head and reference surface therein, and the protective housing is fixed by the housing mounting seat mounted on the load detection surface.

[0016] Preferably, the housing mounting base is elongated and symmetrically positioned on the load detection surfaces on either side of the cantilever. The housing mounting base is a stretchable elastic structure, bonded to the load detection surfaces with glue. The elastic structure of the housing mounting base can prevent deformation of the load detection surfaces. For example, the securing mechanism of the protective housing is formed of rubber and a screw pre-set within the rubber. The protective housing can be made of high-strength engineering plastic.

[0017] The beneficial effects of the present invention are: it effectively solves the problems of the existing wind turbine load measurement device, which is cumbersome to install, difficult to maintain, and a small strain measurement area at the strain gauge measuring point, and cannot ensure that the measurement area produces a corresponding deformation when loaded, thereby causing a large deviation in the measurement results. The wind turbine load measurement device of the present invention has the advantages of simple installation, convenient maintenance and high measurement accuracy, can greatly improve the safety and reliability of wind turbine operation, and has high practical value. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the three-dimensional structure of the interior of the wind turbine load measurement device according to the present invention;

[0019] Figure 2 This is a front view of the internal structure of Example 1 of the present invention;

[0020] Figure 3 yes Figure 2 A top view of

[0021] Figure 4 yes Figure 2 Left view of;

[0022] Figure 5 yes Figure 2 Right view of;

[0023] Figure 6 This is a schematic diagram of a three-dimensional structure of embodiment 1 of the present invention;

[0024] Figure 7 It is a schematic diagram of a three-dimensional decomposition structure of Example 2 of the present invention.

[0025] In the figure: 1. Cantilever rod, 2. Longitudinal displacement detection head, 3. Cantilever mounting seat, 4. Longitudinal reference surface, 5. Detection head mounting seat, 6. Load detection surface, 7. Lifting ear, 8. Positioning rod, 9. Set screw, 10. Fastening nut, 11. Trapezoidal groove, 12. Transverse displacement detection head, 13. Vertical displacement detection head, 14. Transverse reference surface, 15. Vertical reference surface, 16. Protective shell, 17. Shell mounting seat, 18. Screw, 19. Signal line. DETAILED DESCRIPTION

[0026] The specific implementation of the technical solution of the present invention will be further described below through examples and in conjunction with the accompanying drawings.

[0027] Example 1

[0028] In such Figure 1 Figure 2 Figure 3 In the embodiment 1 shown, a wind turbine load measuring device includes a cantilever rod 1 and a longitudinal displacement detection head 2 arranged in the longitudinal direction of the cantilever rod. The fixed end of the cantilever rod is arranged on the cantilever mounting seat 3. The cantilever rod is cylindrical and made of chromium alloy with a low thermal expansion coefficient. One end of the cantilever rod is provided with a thread, and the cantilever mounting seat is provided with a screw hole. The cantilever rod is screwed to the cantilever mounting seat. The suspended end of the cantilever rod is provided with a longitudinal reference surface 4 (see Figure 1 ), the longitudinal reference surface is circular, the diameter of the longitudinal reference surface is larger than the diameter of the cantilever rod, and the longitudinal reference surface is flat. The longitudinal displacement detection head is fixed to the detection head mounting base 5. The detection head mounting base includes a base plate and a detection head mounting plate vertically arranged on the base plate. The lifting ears are arranged at the left and right ends of the detection head mounting plate. The detection head mounting plate is provided with screw holes. The longitudinal displacement detection head is screwed to the detection head mounting plate. A fastening nut 10 is provided between the longitudinal displacement detection head and the detection head mounting plate. The bottom surfaces of the detection head mounting base and the cantilever mounting base are both provided with multiple sets of trapezoidal grooves 11. The detection head mounting base and the cantilever mounting base are both glued to the load detection surface of the wind turbine. The longitudinal displacement detection head is close to the suspended end of the cantilever rod and a measuring gap is provided between the detection end of the longitudinal displacement detection head and the longitudinal reference plane on the cantilever rod. The cantilever mounting seat and the detection head mounting seat are both fixed on the load detection surface 6 of the wind turbine and the cantilever rod is parallel to the load detection surface. A mounting positioning device is also provided between the cantilever mounting seat and the detection head mounting seat. The mounting positioning device includes a lifting ear 7 and a positioning rod 8 symmetrically arranged on the left and right sides of the cantilever mounting seat and the detection head mounting seat (see Figure 4 Figure 5 ), a positioning hole is provided on the lifting ear, the positioning rod is passed through the positioning hole, the positioning rods on both sides are parallel to the cantilever rod and are on the same plane as the cantilever rod, and a set screw 9 for fixing the positioning rod is also provided on the lifting ear; the longitudinal displacement detection head is provided with a photoelectric ranging module and a temperature measurement module.

[0029] The wind turbine load measuring device of this embodiment further includes a protective housing (see Figure 6), a housing mounting seat is provided on the load detection surface, a screw being fixed to the housing mounting seat, and the protective housing is fixed to the load detection surface via the screw. The protective housing is provided with a cable hole for passing the detection head signal line. The housing mounting seat is elongated and symmetrically arranged on the load detection surface on both sides of the cantilever rod. The housing mounting seat is a stretchable elastic structure (rubber in this embodiment) and is bonded to the load detection surface with glue.

[0030] Example 2

[0031] In such Figure 7 In the embodiment 2 shown, the load measuring device also includes a lateral displacement detection head 12 and a vertical displacement detection head 13. The detection head mounting seat is a horizontally placed rectangular box-shaped body. The suspended end of the cantilever rod is located in the box-shaped body. The bottom of the box-shaped body and the two adjacent side walls are provided with screw holes. The longitudinal displacement detection head is screwed to the bottom of the box-shaped body. The lateral displacement detection head and the vertical displacement detection head are respectively screwed to the two adjacent side walls of the box-shaped body. A fastening nut is provided between the detection head and the detection head mounting seat. The suspended end of the cantilever rod is also provided with a lateral reference plane 14 corresponding to the lateral displacement detection head and a vertical reference plane 15 corresponding to the vertical displacement detection head. A measuring gap is provided between the detection end of the lateral displacement detection head and the lateral reference plane, and between the detection end of the vertical displacement detection head and the vertical reference plane. The cantilever rod is cylindrical and made of a chromium alloy with a low thermal expansion coefficient. One end of the cantilever rod is threaded, and the cantilever mounting seat is provided with a screw hole. The cantilever rod and the cantilever mounting seat are screwed together. The free end of the cantilever rod is provided with a rectangular block 16. The end surface of the rectangular block constitutes a longitudinal reference surface corresponding to the longitudinal displacement detection head; the side surface of the rectangular block constitutes a transverse reference surface and a vertical reference surface corresponding to the transverse displacement detection head and the vertical displacement detection head. The longitudinal reference surface, transverse reference surface, and vertical reference surface are all planes. The transverse displacement detection head and the vertical displacement detection head are both equipped with a photoelectric ranging module. Lifting ears are provided on the left and right side walls of the detection head mounting seat. The side wall of the detection head mounting seat opposite the load detection surface is provided with multiple sets of trapezoidal grooves. The detection head mounting seat is glued to the load detection surface of the wind turbine generator. The rest of the embodiment is the same as that of Example 1.

[0032] When installing the load measuring device of the present invention, the positioning rod is first inserted into the ears of the detection head mounting seat and the cantilever mounting seat and fixed with a set screw to limit the freedom of movement of the two and avoid the longitudinal displacement detection head and the cantilever rod from tilting and misaligning their axes in the horizontal or vertical direction during the installation process. After the internal structure of the load measuring device is installed, the two positioning rods need to be removed before installing the protective shell.

[0033] Before installing the load measuring device, first determine the test area (load detection surface) on the inner wall to be tested and select it with a marker. Then, paste the shell mounting base with a screw in this area. Then, install the load measuring device in the selected area between the two shell mounting bases. First, screw the longitudinal displacement detection head into the detection head mounting base and tighten the locking nut. Then, insert the positioning rod into the ears on both sides of the detection head mounting base. Then, tighten the set screws on the ears to ensure that the positioning rod does not slide in the ears. Use glue to stick the detection head mounting base to the test area. Since there is a trapezoidal groove on its bottom, the contact area between the detection head mounting base and the glue is increased, so that the detection head mounting base can be stably and reliably installed on the inner wall. Then screw the cantilever rod into the cantilever mounting base, and connect the cantilever mounting base sleeve into the positioning rod through the ears on both sides of the cantilever mounting base. Move the cantilever mounting base and ensure that one end of the cantilever rod enters the detection range of the longitudinal displacement detection head. At this time, ensure that the original distance from one end of the cantilever rod screwed into the mounting base to the end of the longitudinal displacement detection head with the signal line is L. Finally, use glue to stick the cantilever mounting base to the test area.

[0034] After completing the above steps and the glue is cured, remove the positioning rod and install the protective shell on the shell mounting seat to complete the overall installation of the load measuring device.

[0035] The photoelectric ranging module in the longitudinal displacement detection head emits infrared rays and senses the infrared rays reflected back through the longitudinal reference plane on the cantilever rod. When the inner wall is deformed by the alternating load, the tiny gap between the cantilever rod and the longitudinal displacement detection head changes. At the same time, the intensity of the infrared light reflected back by the longitudinal displacement detection head also changes, and the light intensity change signal is transmitted to the single-chip microcomputer inside the load measurement device via the signal line. The single-chip microcomputer then converts the actual displacement change △l according to the real-time temperature and the thermal expansion coefficient of the cantilever rod material. Finally, the single-chip microcomputer calculates the strain generated when the load measurement device installation area is loaded based on △l / L. The working principles of the lateral displacement detection head and the vertical displacement detection head are similar to those of the longitudinal displacement detection head. Those skilled in the art should understand this and will not be described in detail here.

[0036] In addition to the above-mentioned embodiments, within the scope disclosed in the claims and description of the present invention, the technical features or technical data of the present invention can be reselected and combined to form new embodiments. These can be achieved by those skilled in the art without creative work. Therefore, these embodiments that are not described in detail in the present invention should also be regarded as specific embodiments of the present invention and within the scope of protection of the present invention.

Claims

1. A wind turbine load measuring device, characterized in that: The invention comprises a cantilever rod (1) and a longitudinal displacement detection head (2) arranged in the longitudinal direction of the cantilever rod, wherein the fixed end of the cantilever rod is arranged on a cantilever mounting seat (3), the suspended end of the cantilever rod is provided with a longitudinal reference surface (4), the longitudinal displacement detection head is fixed on a detection head mounting seat (5), the longitudinal displacement detection head is close to the suspended end of the cantilever rod, and a measuring gap is provided between the detection end of the longitudinal displacement detection head and the longitudinal reference surface on the cantilever rod, the cantilever mounting seat and the detection head mounting seat are both fixed on a load detection surface (6) of a wind turbine generator set, and the cantilever rod is parallel to the load detection surface, and an installation positioning device is also provided between the cantilever mounting seat and the detection head mounting seat; The installation and positioning device comprises a lifting lug (7) and a positioning rod (8) symmetrically arranged on the left and right sides of the cantilever mounting seat and the detection head mounting seat; The detection head mounting seat includes a base plate and a detection head mounting plate vertically arranged on the base plate, the lifting ears are arranged on the left and right ends of the detection head mounting plate, and the longitudinal displacement detection head is screwed on the detection head mounting plate.

2. The wind turbine load measuring device according to claim 1, characterized in that: The lifting lug is provided with a positioning hole, the positioning rod is passed through the positioning hole, the positioning rods on both sides are parallel to the cantilever rod and are on the same plane as the cantilever rod, and the lifting lug is also provided with a set screw (9) for fixing the positioning rod; the longitudinal displacement detection head is provided with a photoelectric distance measurement module and a temperature measurement module.

3. The wind turbine load measuring device according to claim 2, characterized in that: A fastening nut (10) is provided between the longitudinal displacement detection head and the detection head mounting plate, and the bottom surfaces of the detection head mounting seat and the cantilever mounting seat are provided with multiple groups of trapezoidal grooves (11), and the detection head mounting seat and the cantilever mounting seat are both bonded to the load detection surface of the wind turbine generator set by glue.

4. The wind turbine load measuring device according to claim 3, characterized in that: The cantilever rod is cylindrical and made of a chromium alloy material with a low thermal expansion coefficient. One end of the cantilever rod is provided with a thread, and the cantilever mounting seat is provided with a screw hole. The cantilever rod is screwed to the cantilever mounting seat. The longitudinal reference plane set at the suspended end of the cantilever rod is circular, the diameter of the longitudinal reference plane is larger than the diameter of the cantilever rod, and the longitudinal reference plane is a plane.

5. The wind turbine load measuring device according to claim 1, characterized in that: The load measuring device further comprises a lateral displacement detection head (12) and a vertical displacement detection head (13); the detection head mounting seat is a horizontally placed rectangular box-shaped body; the suspended end of the cantilever rod is located in the box-shaped body; screw holes are provided on the bottom and two adjacent side walls of the box-shaped body; the longitudinal displacement detection head is screwed onto the bottom of the box-shaped body; the lateral displacement detection head and the vertical displacement detection head are screwed onto two adjacent side walls of the box-shaped body respectively; a fastening nut is provided between the detection head and the detection head mounting seat; the suspended end of the cantilever rod is also provided with a lateral reference surface (14) corresponding to the lateral displacement detection head and a vertical reference surface (15) corresponding to the vertical displacement detection head; a measuring gap is provided between the detection end of the lateral displacement detection head and the lateral reference surface, and between the detection end of the vertical displacement detection head and the vertical reference surface.

6. The wind turbine load measuring device according to claim 5, characterized in that: The cantilever rod is a cylinder and is made of a chromium alloy material with a low thermal expansion coefficient. One end of the cantilever rod is provided with a thread, and the cantilever mounting seat is provided with a screw hole. The cantilever rod is screwed to the cantilever mounting seat. The suspended end of the cantilever rod is provided with a rectangular block, and the end face of the rectangular block constitutes a longitudinal reference plane corresponding to the longitudinal displacement detection head; the side face of the rectangular block constitutes a transverse reference plane and a vertical reference plane corresponding to the transverse displacement detection head and the vertical displacement detection head; the longitudinal reference plane, transverse reference plane and vertical reference plane are all planes; the transverse displacement detection head and the vertical displacement detection head are both provided with a photoelectric ranging module.

7. The wind turbine load measuring device according to claim 5, characterized in that: The lifting ears are set on the left and right side walls of the detection head mounting base. The side wall of the detection head mounting base opposite to the load detection surface is provided with multiple sets of trapezoidal grooves. The detection head mounting base is glued to the load detection surface of the wind turbine.

8. The wind turbine load measuring device according to any one of claims 1 to 7, characterized in that: The wind turbine load measuring device further comprises a protective shell (16), a shell mounting seat (17) is provided on the load detection surface, a screw (18) is fixed on the shell mounting seat, the protective shell is fixed to the load detection surface via the screw, and a cable hole for passing a detection head signal line (19) is provided on the protective shell.

9. The wind turbine load measuring device according to claim 8, characterized in that: The shell mounting seat is in the shape of an elongated strip and is symmetrically arranged on the load detection surfaces on both sides of the cantilever rod. The shell mounting seat is a stretchable elastic structure and is bonded to the load detection surface by glue.

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