WO2018049895A1

WO2018049895A1 - Device and method for monitoring status of blade of wind turbine

Info

Publication number: WO2018049895A1
Application number: PCT/CN2017/092570
Authority: WO
Inventors: 王兴波; 张国涛; 郝刘峰
Original assignee: 北京金风科创风电设备有限公司
Priority date: 2016-09-14
Filing date: 2017-07-12
Publication date: 2018-03-22
Also published as: CN106286152B; CN106286152A

Abstract

A device and method for monitoring the status of a blade of a wind turbine are provided. The monitoring device comprises a sensor (5) and a controller. The sensor (5) is disposed on a tower (9), a cabin, a hub, or a generator of the wind turbine having the blade (8), and monitors a distance between the sensor (5) and a suction surface of the blade (8) to obtain current distance data between the suction surface of the blade (8) and the sensor (5). The controller is connected to the sensor (5) to receive the current distance data output by the sensor (5), and determines a torsional state of the blade (8) on the basis of initial distance data between the suction surface of the blade (8) and the sensor (5) and the current distance data. The monitoring device monitors the distance between the sensor (5) and the blade (8) by means of the external sensor, and determines whether a torsional deformation of the blade is too large on the basis of the obtained current distance data and initial distance data, so as to determine whether the blade (8) is at risk of cracking or structural abnormalities, such that corresponding maintenance and other remedial measures can be taken in time to reduce loss caused by cracking of the blade (8), and reduce costs caused by blade component replacement.

Description

Wind turbine generator blade state monitoring device and monitoring method

This application claims the priority of the invention patent application filed on Sep. 14, 2016, the Chinese Patent Office, the application No. 201610826920.8, the title of the invention is "the blade state monitoring device of the wind turbine and the monitoring method", the entire contents of which are incorporated by reference. In this application.

Technical field

The invention relates to the technical field of wind power, in particular to a monitoring device and a monitoring method for monitoring the torsional deformation state of a blade of a wind power generator to determine whether the blade has cracking or other structural abnormality resulting in excessive torsion.

Background technique

In recent years, the wind power industry has developed rapidly, and the installed capacity is increasing every year. The problems brought by the wind power industry are also highlighted. It is limited by the manual processing of blade processing and manufacturing, and the manufacturing, process and quality control. On the other hand, if there is a defect in a certain operation, after the wind farm is installed for a period of time, there will be incidents such as blade cracking, power drop, blade breakage or even overall collapse of the whole machine, which brings cost increase and reputation to the whole plant and the owner. Affected, loss of power generation and other issues.

In this regard, monitoring means can be used to monitor the state of the fan blades in real time to determine whether the blade has the risk of cracking or structural abnormality, and timely take corresponding repair and other remedial measures to reduce the loss caused by blade cracking, and save blade parts. The cost of replacement.

A rotor blade condition monitoring system of the prior art includes at least one sensor and a controller configured to sense vibration of a rotor blade and transmit at least one monitoring signal indicative of the sensed vibration, the controller being electrically coupled to A sensor is configured to receive a monitoring signal from the sensor, and the controller can determine a state of the rotor blade based on the received monitoring signal.

Another wind turbine blade edge monitoring system of the prior art includes any configuration of sensors disposed within an interior cavity of a rotor blade, wherein the sensor is oriented relative to a leading or trailing edge of the blade and configured to detect physics within the blade A characteristic that indicates the occurrence of a separation between the housing members along the edge being monitored, the controller being configured to receive a signal from the sensor and initiate an automatic response to the detected separation.

Both blade monitoring systems and methods monitor the blade status by sensors and then The sensor data is calculated and analyzed to determine whether the blade is in a normal state. However, the sensors need to be installed inside the blade in a special way. The structure is complicated, the assembly is difficult, the manufacturing cost is high, and the measurement accuracy and stability are poor. Once the monitoring system itself fails, it needs to be shut down. Maintenance is difficult and maintenance costs are high. In addition, it is not suitable for upgrading wind turbines that have already been put into use.

Therefore, how to overcome the defects of the above-described fan blade state monitoring device and method is a technical problem that a person skilled in the art needs to solve.

Summary of the invention

It is an object of the present invention to provide a blade condition monitoring device for a wind power plant. The monitoring device monitors the distance between the sensor and the blade through an external sensor, and determines whether the torsional deformation of the blade is too large according to the obtained actual distance data and the initial distance data, thereby obtaining whether the blade has a risk of cracking or structural abnormality. In case of timely remedial measures such as maintenance, reduce the loss caused by blade cracking, and save the cost of blade parts replacement.

Another object of the present invention is to provide a method of monitoring a blade condition of a wind power generator.

To achieve the above object, the present invention provides a blade state monitoring device for a wind power generator, comprising:

a sensor disposed on the tower of the wind turbine set on which the blade is located, on the hub, on the nacelle or on the generator, for monitoring the distance between the sensor and the suction surface of the blade, and obtaining the suction surface of the blade Actual distance data between the sensors;

a controller, connecting the sensor to receive actual distance data output by the sensor, and determining a torsion state of the blade according to initial distance data between the blade suction surface and the sensor and the actual distance data .

Preferably, the sensor is disposed on the tower by a synchronization mechanism; the synchronization mechanism is disposed on the outer surface of the tower for carrying the sensor, and drives the sensor to surround the tower in a circumferential direction Rotating, the synchronizing mechanism rotates synchronously with the nacelle when the wind turbine is yawed.

Preferably, the synchronization mechanism comprises:

a power component electrically connected to the controller;

An annular slide rail disposed circumferentially on an outer wall of the tower;

a transmission component for driving the sensor to move along the annular slide under the driving of the power component.

Preferably, the transmission member comprises an annular toothed belt and a gear; the toothed belt is disposed on an outer wall of the tower, and is arranged in parallel with the annular sliding rail; the gear is connected to the power component a power output end and meshing with the toothed belt.

Preferably, the transmission component comprises a slider, pulley or sliding sleeve mounted on the annular slide.

Preferably, the monitoring position of the sensor is disposed on the tower corresponding to a selected portion between a maximum chord length portion of the blade and a tip portion.

Preferably, the monitoring position of the sensor is disposed on one or both, or both of the tip portion, the mid-leaf portion, and the maximum chord portion of the blade on the tower.

Preferably, the sensor is disposed on or on the outer rotor of the generator of the wind turbine.

To achieve the above second object, the present invention provides a method for monitoring a blade state of a wind power generator, comprising:

Positioning a sensor on a tower of the wind turbine set on which the blade is located, on a nacelle or on a generator, monitoring a distance between the sensor and the suction side of the blade, obtaining the suction side of the blade and the sensor Actual distance data between;

The controller receives actual distance data output by the sensor, and determines a torsion state of the blade according to initial distance data between the blade suction surface and the sensor and the actual distance data.

Further, the sensor monitors its distance from the suction side of the blade when the blade is turned to the vertical direction.

Further, the receiving the actual distance data output by the sensor, and determining the twist state of the blade according to the initial distance data between the blade suction surface and the sensor and the actual distance data includes:

Obtaining an actual twist angle of the blade according to initial distance data between the suction surface of the blade and the sensor and the actual distance data;

Comparing the actual twist angle with a set twist angle, if the actual twist angle Above the set twist angle, it is determined that the blade is at risk of abnormality or cracking.

Further, if the actual twist angle is greater than the set twist angle, an alarm or a stop occurs.

Further, the obtaining the actual twist angle of the blade according to the initial distance data between the blade suction surface and the sensor and the actual distance data comprises:

Monitoring a distance between the leading edge and the trailing edge of the blade and the sensor to obtain an actual distance between the leading edge and the trailing edge of the blade and the sensor;

An actual twist angle of the blade is obtained based on an initial distance between the leading and trailing edges of the blade and the actual distance and the actual distance.

Further, if the wind turbine completes yaw, the sensor is controlled to move synchronously with the blade around the tower in a circumferential direction.

The blade state monitoring device and method for a wind power generator provided by the present invention monitors the distance between the sensor and the blade through an external sensor, and determines whether the torsional deformation of the blade is too large according to the obtained actual distance data and the initial distance data. Furthermore, it is concluded that there is a risk of cracking or structural abnormality of the blade, and timely remedial measures such as maintenance are taken to reduce the loss caused by blade cracking, and at the same time, the cost increase by replacing the blade component is saved; and, by monitoring the blade torsional deformation In the subsequent development of the blade design process, increase the angle of attack caused by torsional deformation, and play a guiding role. At the same time, considering the torsional deformation of the blade from the angle of the hanging blade, it can guide the aerodynamic and structural design. .

In addition, the sensor is arranged on the tower of the wind turbine where the blade is located, on the nacelle or on the generator, and is relatively independent from the blade, and has the advantages of simple structure, easy assembly and maintenance, low manufacturing and maintenance cost, and measurement accuracy and stability. Significantly improved, not only for new wind turbines, but also for upgrading wind turbines already in use.

DRAWINGS

1 is a schematic structural view of a wind power generator set with a blade state monitoring device for a wind power generator provided by the present invention at a position corresponding to a blade tip;

2 is a partially enlarged schematic view showing a blade state monitoring device and a blade of the wind power generator set shown in FIG. 1;

Figure 3 is a deformation diagram of a section of a conventional blade;

Figure 4 is a running measurement diagram before and after blade torsional deformation;

Fig. 5 is a monitoring deformation diagram before and after blade torsional deformation.

In the picture:

1. Inverter motor 2. Slide rail slider 3. Slide rail 4. Gearbox 5. Sensor 6. Gear 7. Toothed belt 8. Blade 9. Tower

detailed description

The present invention will be further described in detail below in conjunction with the drawings and embodiments.

Please refer to FIG. 1 and FIG. 2 . FIG. 1 is a schematic structural view of a wind power generator set. The tower state monitoring device of the wind power generator provided by the present invention is disposed on the tower at a position corresponding to the blade tip; FIG. 2 is FIG. 1 . A partially enlarged schematic view of the blade condition monitoring device and the blade of the wind turbine shown.

As shown, in one embodiment, a blade state monitoring device for a wind power generator provided by the present invention includes a sensor 5, a synchronization mechanism, and a controller (not shown), wherein the sensor 5 is a distance The sensor is disposed outside the tower 9 and at a certain height for monitoring the distance between the sensor 5 and the suction surface of the blade 8; the synchronization mechanism is disposed on the outer wall of the tower 9 for carrying the sensor 5 and driving the sensor 5 along The circumferential direction moves synchronously with the blade 8 around the tower 9; the controller is communicatively coupled to the sensor 5 to receive the monitoring signal of the sensor 5 and to determine the torsional state of the blade 8 based on the monitoring signal.

Specifically, the synchronizing mechanism includes a toothed belt 7 that circumferentially surrounds the tower 9 in the circumferential direction, a slide rail 3 that also surrounds the tower 9 in the circumferential direction, a gear 6, a slide rail slider 2, a reduction box 4, and a frequency conversion Motor 1, the use of variable frequency motor can greatly improve the degree of mechanical automation and synchronization, save energy, and help reduce the size of the synchronization mechanism. Of course, other types of motors can be used depending on actual needs.

The rail slide 3 and the toothed belt 7 are mounted on the outer surface of the tower 9 at intervals, and the side of the reduction box 4 is connected to the slide slider 2 mounted on the slide rail 3 for position fixing. And sliding around the tower 9, the variable frequency motor 1 is mounted above the reduction gear box 4 for power driving, the reduction gear box 4 Below the gear unit 6 is mounted, the gear 6 meshes with the toothed belt 7 on the surface of the tower 9, and the sensor 5 is mounted on the outer side of the reduction gear box 4 for distance measurement. Of course, in addition to the slide slider 2, the reduction gear box 4 and the slide rail 3 can also be slidably connected by other transmission members such as a pulley or a sliding sleeve.

When the variable frequency motor 1 drives the reduction gear box 4 to rotate, the reduction gear box 4 drives the gear 6 to rotate on the toothed belt 7, thereby driving the reduction gear box 4 together with the sensor 5 and the variable frequency motor 1 to make a rotary motion on the slide rail 3 . In this way, when the fan is yawed, the sensor 5 can be yawed to the corresponding position synchronously, and the torsional deformation of the blade 8 can be monitored at all times.

Although the embodiment only has one sensor 5 for monitoring the deformation of the tip region of the blade, those skilled in the art can understand that two or more sensors can also be mounted on the tower 9, and a slewing mechanism is provided for each sensor. To monitor the torsional deformation of the blade tip, the blade, and the maximum chord length of the blade 8, respectively, and the plurality of sensors may share the same controller, or multiple sets of mutually independent monitoring devices may be installed on the tower to monitor the blade respectively. Torsional deformation of the tip, the middle of the leaf, the maximum chord length, etc., and each sensor is connected to a different controller. Of course, in addition to monitoring the tip, leaf, and maximum chord length of the blade 8, other portions of the blade can be monitored.

Further, the synchronizing mechanism is not limited to the above specific form, and any slewing mechanism capable of driving the sensor 5 and the vane 8 to be yawed synchronously can be used for the purpose of the present invention. For example, the upper and lower positions of the above-mentioned slide rail 3 and the toothed belt 7 may be reversed from each other, or instead of the gear 6 and the toothed belt 7 mechanism, an annular rotary platform is mounted on the outer wall of the tower 9, and then the sensor 5 is mounted. It is rotatably mounted on a swivel platform, and so on.

Please refer to FIG. 3, FIG. 4 and FIG. 5 together. FIG. 3 is a deformation diagram of a certain section of the conventional blade; FIG. 4 is an operation measurement diagram before and after the blade torsional deformation; FIG. 5 is a monitoring deformation diagram before and after the blade torsional deformation.

As shown in the figure, when the fan rotor rotates to generate electricity, the starting wind speed, the rated wind speed and the cut-out wind speed are generally set. For example, the starting wind speed is 3m/s, the rated wind speed is 10m/s, and the cut-out wind speed is 25m/s. 8 Before the rated wind speed, the pitching strategy is not adopted. After the wind speed exceeds the rated wind speed of 10m/s, the blade 8 is pitched, and after the wind speed exceeds the cut-out wind speed of 25m/s, the blade 8 stops off; the wind wheel runs in the cutting At this stage before the wind speed, the maximum value of the torsional deformation of the blade 8 itself is generally less than or equal to 2°. If the measured torsional deformation is too large, the problem is solved in the blade design stage from the perspective of aerodynamics and structure, respectively.

The measure adopted by the present invention for monitoring the torsional deformation of the blade is (taking a certain blade as an example): when the fan is yawed, the controller outputs a yaw signal to the variable frequency motor 1, and drives the reduction gearbox 4 through the variable frequency motor 1 on the surface of the tower 9. Moving to the position between the blade 8 and the tower 9, when the blade 8 is running, the sensor 5 located on the reduction gearbox 4 starts measuring the horizontal distance from the surface of the blade 8, measuring the airfoil from point A of Fig. 4 to The distance from the sensor 5, when running to point B, can obtain the running curve as shown in Fig. 3, so combined with the relative position of the blade 8 at the position after the fan blade is hung, it can be judged whether the section has a large torsional deformation.

For example, in FIG. 4, the right side is a section of the blade 8 that is operated after the twist angle, and the deformation of the point A and the point B with the running time of the fan, that is, the deformation position shown by the broken line in FIG. 5, is measured by the distance sensor 5, combined with The position before the position deformation is judged to have a torsional deformation of 5° at the cross-section position. According to the design of the pneumatic torsion angle and the angle of attack data at the position, it is judged that the position is stalled, and the blade cracking, the power generation curve abnormality, etc. may have occurred. phenomenon.

Corresponding to the output of the torsional deformation, an alarm signal can be set, that is, the torsional deformation exceeds the set value (for example, the torsional deformation is set to ≥ 3°, and the consideration of the set value is mainly the torsional deformation of the blade corresponding to different wind speeds, and the whole The size of the machine component, the angle of the cabin tilt, and the pitch angle of the blade, etc., issue a warning signal, and the fan is stopped in time by manual control to check whether the entire blade 8 is damaged or cracked;

At the same time, by monitoring the torsional deformation of the blade 8 position, especially the torsional deformation of the tip region, it can be compared with the theoretical design value to provide actual operational data support for the aerodynamic design and structural design of the blade, and better iterative optimization of the blade. design.

The above embodiments are only preferred embodiments of the present invention, and are not limited thereto. On this basis, targeted adjustments can be made according to actual needs, thereby obtaining different implementation manners. For example, the distance sensor 5 is mounted on the ground to monitor the torsional deformation of the blade 8; alternatively, the distance sensor 5 is mounted on the hub to monitor the torsional deformation of the blade 8, or, on the nacelle, the distance sensor is mounted above, below and to the side 5. Monitor the torsional deformation of the blade 8; or alternatively, mount the sensor on the outer or outer stator of the direct drive generator, and the like. Since there are many ways to implement, there is no longer an example here.

If the sensor is mounted on the outer rotor of the hub or the generator, since the outer rotor of the nacelle and the generator itself can be rotated synchronously with the blade when the whole machine is yawed, the synchronization mechanism can be omitted.

In addition to the above monitoring device, the present invention also provides a method for monitoring a blade state of a wind power generator, comprising:

S01: The sensor 5 is disposed outside the tower 9 and located at a monitoring position of a certain height, and the distance between the sensor 5 and the suction surface of the blade 8 is monitored;

S02: Receive the monitoring signal of the sensor 5, and judge the torsion state of the blade 8 according to the monitoring signal.

Further, in step S01: when the blade 8 is turned to the vertical direction, it is just axially aligned with the sensor 5, entering the monitoring range of the sensor 5, and the sensor 5 monitors the distance between it and the suction surface of the blade 8.

Further, in step S02, the monitoring signal of the sensor 5 is received, and the torsion state of the blade 8 is determined according to the monitoring signal, which can be specifically achieved by:

Monitoring the distance between the suction surface of the blade 8 and the sensor 5, and obtaining actual distance data between the suction surface of the blade 8 and the sensor 5;

Obtaining the actual twist angle of the blade 8 according to the initial distance data and the actual distance data between the suction surface of the blade 8 and the sensor 5;

The actual torsion angle is compared with the set torsion angle, and if the actual torsion angle is greater than the set torsion angle, it is determined that the blade 8 is at risk of abnormality or cracking.

Further, the distance between the suction surface of the blade 8 and the sensor 5 is monitored, and the actual distance data between the suction surface of the blade 8 and the sensor 5 is obtained; according to the initial distance data and the actual distance data between the suction surface of the blade 8 and the sensor 5, Obtaining the actual twist angle of the blade 8 can be achieved in the following manner:

Monitoring the distance between the leading edge and the trailing edge of the blade 8 and the sensor 5 to obtain the actual distance between the leading edge and the trailing edge of the blade 8 and the sensor 5;

The actual twist angle of the blade 8 is obtained from the initial and actual distances between the leading and trailing edges of the blade 8 and the sensor 5.

Further, the method further includes the step S03: if the fan is yawed, the control sensor 5 moves synchronously with the blade 8 in the circumferential direction around the tower to ensure that the torsional deformation of the blade 8 can be monitored at all times.

For the same reason, in addition to installing the sensor on the tower 9, it is also possible to mount the sensor above, below or to the side of the nacelle, or to mount the sensor on the outer rotor of the direct drive generator. in case The sensor is installed on the outer rotor of the nacelle or the generator. Since the outer rotor of the nacelle and the generator itself can be rotated synchronously with the blade when the whole machine is yawed, the steps of controlling the synchronous rotation of the sensor and the blade can be omitted. .

The specific implementation of the above steps has been described in detail in the embodiment of the monitoring device. To save space, it will not be repeated here. Please refer to the above.

It should be noted here that in the process of processing the sensor detection data, the distance between the blade and the tower under the action of the wind during operation can be compensated according to the wind speed, so as to further improve the accuracy of the monitoring, and During the monitoring process, the three blades of the wind turbine will sequentially circulate through the monitoring area of the sensor. Since the shape and performance parameters of the three blades should be consistent, it can be regarded as the monitoring data of the same blade. The results show that there is a risk of abnormality or cracking, which means that one or two or even three of the leaves have an abnormality or risk of cracking.

The monitoring device and method provided by the invention install a distance sensor on the tower, on the nacelle or on the generator, and monitor the inconsistency of the deformation of the front and rear edges of the blade at different positions by the distance sensor, and judge whether the trailing edge of the blade is cracked according to the torsional deformation of the blade or Abnormal structure, timely take appropriate remedial measures such as maintenance, greatly reduce the loss caused by blade cracking, save the cost of blade component replacement; at the same time, by monitoring the blade without cracking or structural abnormality, by measuring the leading edge of the blade and The distance of the trailing edge is used to judge the torsional deformation of the different sections of the blade, which serves as a guiding reference for the aerodynamic and structural design of the blade.

The blade state monitoring device and monitoring method of the wind power generator provided by the present invention are described in detail above. The principles and embodiments of the present invention have been described herein with reference to specific examples. The description of the above embodiments is only for the purpose of understanding the core concepts of the present invention. It should be noted that those skilled in the art can make various modifications and changes to the present invention without departing from the spirit and scope of the invention.

Claims

A blade state monitoring device for a wind power generator, comprising:

a sensor (5) disposed on a tower (9) of the wind turbine on which the blade (8) is located, on a nacelle, on a hub or on a generator for monitoring the sensor (5) and the blade (8) the distance of the suction surface, obtaining actual distance data between the suction surface of the blade (8) and the sensor (5);

a controller that connects the sensor (5) to receive actual distance data output by the sensor (5), and according to initial distance data between the suction surface of the blade (8) and the sensor (5) and The actual distance data determines the torsion state in which the blade (8) is located.
A blade state monitoring device for a wind power generator according to claim 1, wherein said sensor (5) is disposed on a tower (9) by a synchronization mechanism; said synchronization mechanism being disposed in said tower (9) On the outer surface, for carrying the sensor (5), and driving the sensor (5) to rotate around the tower (9) in a circumferential direction, the synchronization mechanism when the wind turbine is yaw Rotate synchronously with the nacelle.
The blade state monitoring device for a wind power generator according to claim 2, wherein the synchronization mechanism comprises:

a power component electrically connected to the controller;

An annular slide rail disposed circumferentially on an outer wall of the tower (9);

a transmission component for driving the sensor (5) to move along the annular slide under the driving of the power component.
A blade state monitoring device for a wind power generator according to claim 3, wherein said transmission member comprises an annular toothed belt (7) and a gear (6); said toothed belt (7) is provided at the The outer wall of the tower (9) is arranged in parallel with the annular slide; the gear (6) is connected to the power output of the power component and meshes with the toothed belt (7).
A blade state monitoring device for a wind power generator according to claim 3, wherein said transmission member comprises a slider, a pulley or a sliding sleeve mounted on said annular slide.
A blade state monitoring device for a wind power generator according to any one of claims 2 to 5, characterized in that the monitoring position of the sensor (5) is set on the tower (9) corresponding to the blade (8) The selected portion between the maximum chord length and the tip position.
Blade condition monitoring device for wind power generator set according to any one of claims 2 to 5 The monitoring position of the sensor (5) is set on one of a tip portion, a mid-leaf portion, and a maximum chord portion corresponding to the blade (8) on the tower (9) , two or three.
A blade state monitoring device for a wind power generator according to any one of claims 1 to 5, characterized in that the sensor (5) is arranged on the outer rotor or on the outer stator of the generator of the wind turbine.
A method for monitoring a state of a blade of a wind power generator, comprising:

Locating the sensor (5) on the tower (9) of the wind turbine on which the blade (8) is located, on the nacelle or on the generator, monitoring the sensor (5) and the suction surface of the blade (8) The distance between the suction surface of the blade (8) and the actual distance between the sensor (5) is obtained;

The controller receives actual distance data output by the sensor (5), and determines the blade according to initial distance data between the suction surface of the blade (8) and the sensor (5) and the actual distance data (8) ) the state of twist.
A method for monitoring a state of a blade of a wind power generator according to claim 9, wherein said sensor (5) monitors its suction surface with said blade (8) when said blade (8) is turned to a vertical direction The distance between them.
The method for monitoring a state of a blade of a wind power generator according to claim 9, wherein said receiving said actual distance data output by said sensor (5) is based on said suction surface of said blade (8) and said sensor ( The initial distance data between 5) and the actual distance data determine that the torsion state of the blade (8) is:

Obtaining an actual twist angle of the blade (8) according to initial distance data between the suction surface of the blade (8) and the sensor (5) and the actual distance data;

The actual torsional angle is compared with a set torsion angle, and if the actual torsion angle is greater than the set torsion angle, it is determined that the blade (8) is at risk of abnormality or cracking.
The method for monitoring a state of a blade of a wind power generator according to claim 11, wherein if the actual twist angle is greater than the set twist angle, an alarm or a shutdown occurs.
The method for monitoring a state of a blade of a wind power generator according to claim 11, wherein said initial distance data between said suction surface of said blade (8) and said sensor (5) and said actual distance data Obtaining the actual twist angle of the blade (8) includes:

Monitoring the distance between the leading edge and the trailing edge of the blade (8) and the sensor (5) to obtain an actual distance between the leading edge and the trailing edge of the blade (8) and the sensor (5);

The actual twist angle of the blade (8) is obtained from the initial distance between the leading edge and the trailing edge of the blade (8) and the sensor (5) and the actual distance.
The method for monitoring a state of a wind turbine of a wind power generator according to any one of claims 9 to 13, wherein if the wind turbine completes yaw, the sensor (5) is controlled in a circumferential direction and said The blades (8) move synchronously around the tower (9).