Wind turbine generator blade clearance monitoring, error evaluation and threshold optimization method and system

Abstract

The invention discloses a wind turbine generator blade clearance monitoring, error evaluation and threshold optimization method and system, and the method comprises the steps: monitoring a blade clearance value of a wind turbine generator in real time through clearance monitoring equipment, and synchronously measuring a distance value from a blade tip to a tower wall in the wind turbine generator through an installed calibration radar. And comparing the blade clearance value measured at each time point in the time period with the distance value, and determining clearance difference values corresponding to different time points. Statistical analysis is carried out on the clearance difference values corresponding to all the time points in the specified time range, the clearance difference mean value in the time range is determined, and the clearance monitoring error of the wind turbine generator can be evaluated and the clearance alarm threshold value can be optimized through the clearance difference mean value. Therefore, the influence of factors such as cabin glass fiber flatness, a cabin inclination angle, a clearance equipment installation angle and a tower drum inclination angle on clearance alarm monitoring is eliminated, and the power generation loss caused by clearance false alarm is effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of measuring the clearance distance of a wind turbine generator set, and in particular to a method and system for wind turbine generator set blade clearance monitoring, error evaluation, and threshold optimization. Background Art

[0002] With the increase in the unit capacity and blade length of wind turbines, the operational safety and reliability of blades have become the key to ensuring power stability. Through clearance monitoring, the position information of the blade tip can be obtained in real time, and protection strategies can be taken in time when facing the risk of tower sweeping to ensure the safety of the unit. Currently, widely used clearance equipment includes millimeter wave radar, laser radar, video clearance radar, etc., which have the advantages of easy installation and good real-time performance. However, due to the influence of the flatness of the cabin glass fiber, the cabin inclination, the installation angle of the clearance equipment and the inclination of the tower, there is an error between the actual measurement results of the blade and the calculated clearance, which has a great impact on the blade root limit load design and the increase in power generation. Therefore, accurately evaluating the error of the clearance value has important guiding significance for the unit design. Summary of the invention

[0003] In view of the shortcomings of the prior art, the present invention proposes a method and system for wind turbine blade clearance monitoring, error assessment, and threshold optimization, which can accurately assess the blade clearance monitoring error of wind turbines. The specific technical solution is as follows:

[0004] In a first aspect, a method for evaluating blade clearance monitoring errors of a wind turbine is provided. In a first implementable manner of the first aspect, the method comprises:

[0005] Obtain the blade clearance value measured by the clearance monitoring equipment within a specified time range, and the distance value from the blade tip to the tower wall of the wind turbine obtained by synchronous measurement of the calibration radar;

[0006] Calculate the clearance difference corresponding to different time points within a specified time range according to the corresponding blade clearance value and distance value;

[0007] The mean clearance difference within the specified time range is calculated, and the blade clearance monitoring error of the wind turbine is evaluated based on the mean clearance difference.

[0008] In combination with the first implementable manner of the first aspect, in a second implementable manner of the first aspect, obtaining a blade clearance value measured by a clearance monitoring device includes:

[0009] Acquire multiple blade images continuously collected by the video clearance radar, and identify and locate the position coordinates of the target points in each blade image respectively;

[0010] The Euclidean distance from each target point to the tower projection surface is calculated according to the corresponding position coordinates, and the minimum distance value is selected as the blade clearance value.

[0011] In combination with the first implementable manner of the first aspect, in a third implementable manner of the first aspect, obtaining the distance value measured by the calibration radar includes:

[0012] Obtain the blade pitch angle and nacelle yaw angle of the wind turbine in real time;

[0013] When the blade pitch angle reaches a preset angle, the calibration radar is placed on the extension line of the direction indicated by the yaw angle of the nacelle, and the vertical displacement difference between the calibration radar and the tower base of the wind turbine is adjusted.

[0014] In a second aspect, a method for optimizing a wind turbine blade clearance monitoring alarm threshold is provided, comprising:

[0015] Obtain the blade clearance value measured by the clearance monitoring equipment within a specified time range, and the distance value from the blade tip to the tower wall of the wind turbine obtained by synchronous measurement of the calibration radar;

[0016] Calculate the clearance difference corresponding to different time points within a specified time range according to the corresponding blade clearance value and distance value;

[0017] Count the average of the clearance difference within the specified time range, and optimize the preset alarm threshold based on the average of the clearance difference.

[0018] In a third aspect, a method for monitoring the clearance of blades of a wind turbine is provided. In a first achievable manner of the third aspect, the method comprises:

[0019] The wind turbine blade clearance monitoring alarm threshold optimization method as described in the second aspect is adopted to optimize the alarm threshold corresponding to the wind turbine.

[0020] In combination with the first implementable manner of the third aspect, in a second implementable manner of the third aspect, further comprising:

[0021] The vertical distance between the clearance monitoring device and the blade tip plane is measured, and the installation angle of the clearance monitoring device is adjusted according to the distance value measured by the calibration radar.

[0022] In a fourth aspect, a wind turbine blade clearance monitoring error assessment system is provided, comprising:

[0023] An acquisition module is configured to acquire a blade clearance value measured by a clearance monitoring device within a specified time range, and a distance value from a blade tip to a tower wall of a wind turbine generator set obtained by synchronous measurement of a calibration radar;

[0024] A calculation module, configured to calculate the clearance difference corresponding to different time points within a specified time range according to the corresponding blade clearance value and distance value;

[0025] The evaluation module is configured to calculate the mean value of the clearance difference within a specified time range and evaluate the blade clearance monitoring error of the wind turbine according to the mean value of the clearance difference.

[0026] In a fifth aspect, a wind turbine blade clearance monitoring alarm threshold optimization system is provided, comprising:

[0027] An acquisition module is configured to acquire a blade clearance value measured by a clearance monitoring device within a specified time range, and a distance value from a blade tip to a tower wall of a wind turbine generator set obtained by synchronous measurement of a calibration radar;

[0028] A calculation module, configured to calculate the clearance difference corresponding to different time points within a specified time range according to the corresponding blade clearance value and distance value;

[0029] The optimization module is configured to calculate the average value of the clearance difference within a specified time range and optimize the preset alarm threshold value based on the average value of the clearance difference.

[0030] In a sixth aspect, a wind turbine blade clearance monitoring system is provided, comprising:

[0031] The threshold optimization module is configured to optimize the alarm threshold corresponding to the wind turbine using the wind turbine blade clearance monitoring alarm threshold optimization method as described in claim 4.

[0032] Beneficial effect: By adopting the wind turbine blade clearance monitoring, error assessment, and threshold optimization method and system of the present invention, the error of the clearance monitoring equipment can be accurately assessed by comparing the blade clearance value measured by the clearance monitoring equipment with the distance value measured by the calibration radar in real time, and the power generation loss caused by the triggering of the unit protection mode due to the clearance false alarm can be effectively reduced, which has good guiding value for the blade root limit load design, power generation improvement, and unit safety control strategy. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] In order to more clearly illustrate the specific implementation of the present invention, the following will briefly introduce the drawings required for use in the specific implementation. In all the drawings, each element or part is not necessarily drawn according to the actual scale.

[0034] Figure 1 A flow chart of a method for evaluating wind turbine blade clearance monitoring errors provided by an embodiment of the present invention;

[0035] Figure 2 A flow chart of a method for optimizing a wind turbine blade clearance monitoring alarm threshold value provided by an embodiment of the present invention;

[0036] Figure 3 A system block diagram of a wind turbine blade clearance monitoring error assessment system provided by an embodiment of the present invention;

[0037] Figure 4 A system block diagram of a wind turbine blade clearance monitoring alarm threshold optimization system provided by an embodiment of the present invention;

[0038] Figure 5 Schematic diagram of the measurement principle for calibrating the radar;

[0039] Figure 6 Measurement data for video clearance radar and calibration radar. DETAILED DESCRIPTION

[0040] The following embodiments of the technical solution of the present invention are described in detail in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the protection scope of the present invention.

[0041] like Figure 1 The flowchart of the wind turbine blade clearance monitoring error evaluation method shown in FIG. 1 includes:

[0042] Step 1: obtaining the blade clearance value measured by the clearance monitoring equipment within a specified time range, and the distance value from the blade tip to the tower wall of the wind turbine generator set obtained by synchronous measurement of the calibration radar;

[0043] Step 2: Calculate the clearance difference corresponding to different time points within a specified time range according to the corresponding blade clearance value and distance value;

[0044] Step 3: Calculate the mean value of the clearance difference within the specified time range, and evaluate the blade clearance monitoring error of the wind turbine according to the mean value of the clearance difference.

[0045] Specifically, firstly, the existing clearance monitoring equipment, such as millimeter wave radar, laser radar, video clearance radar, etc., can be used to monitor the clearance value of the wind turbine blades in real time. At the same time, the distance from the blade tip to the tower wall of the wind turbine can be synchronously measured by the installed calibration radar. The data obtained are as follows: Figure 6 As shown. Then, compare the blade clearance value measured by the clearance monitoring device at each time point within the specified time range with the distance value measured by the calibration radar to determine the clearance difference between the clearance monitoring device and the calibration radar at that time point. Finally, by statistically analyzing the clearance differences corresponding to all time points within the specified time range, the mean clearance difference within the time range is determined, and the blade clearance monitoring error of the wind turbine can be accurately evaluated by the mean clearance difference. At the same time, the clearance monitoring error at the current time point can also be accurately evaluated based on the clearance difference and blade clearance value corresponding to the time point. The specific calculation formula is as follows:

[0046]

[0047] Where N is the number of time points within the time range, At is the leaf clearance value corresponding to time point t, B t is the distance value corresponding to time point t.

[0048] In this embodiment, optionally, in step 1, obtaining a blade clearance value measured by a clearance monitoring device includes:

[0049] Acquire multiple blade images continuously collected by the video clearance radar, and identify and locate the position coordinates of the target points in each blade image respectively;

[0050] The Euclidean distance from each target point to the tower projection surface is calculated according to the corresponding position coordinates, and the minimum distance value is selected as the blade clearance value.

[0051] Specifically, the clearance monitoring device can use a video clearance radar, which can continuously collect multiple blade video images of three blades of the wind turbine, and use existing image recognition and positioning technology to locate the position coordinates of the target point in each blade video image that can be used to calculate the blade clearance. In this embodiment, the blade tip can be selected as the target point.

[0052] Then, the Euclidean distance from each target point to the tower projection plane is calculated according to the corresponding position coordinates. As the blade is rotating, when the blade is in the video clearance radar shooting area, multiple target points will be continuously acquired, some of which are not clearance. Therefore, the minimum distance value is finally selected from the Euclidean distances corresponding to all target points as the blade clearance value. The specific calculation formula for the Euclidean distance from the target point to the tower projection plane is as follows:

[0053]

[0054] Among them, x1, y1, z1 are the position coordinates of the target point, and x2, y2, z3 are the position coordinates of the projection point of the target point on the tower projection plane.

[0055] It should be understood that this embodiment only takes the video clearance radar as an example, but the present application is not limited to this. Other clearance monitoring equipment can also be used to measure the blade clearance value, such as millimeter wave radar and laser radar.

[0056] In this embodiment, optionally, in step 1, obtaining the distance value measured by the calibration radar includes:

[0057] Obtain the blade pitch angle and nacelle yaw angle of the wind turbine in real time;

[0058] When the blade pitch angle reaches a preset angle, the calibration radar is placed on the extension line of the direction indicated by the yaw angle of the nacelle, and the vertical displacement difference between the calibration radar and the tower base of the wind turbine is adjusted.

[0059] Specifically, the calibration radar is installed near the wind turbine. When the calibration radar is installed, the blade pitch angle and the cabin yaw angle of the wind turbine can be measured in real time. When the blade pitch angle reaches 89° or 90°, the calibration radar can be installed on the extension line of the direction indicated by the cabin yaw angle, so that the normal of the calibration radar sweeping the plane coincides with the extension line of the direction indicated by the cabin yaw angle, so as to ensure that the initial installation position of the calibration radar is directly opposite to the wind rotor rotation plane, and reduce the calculation error generated by the calibration radar. Finally, the vertical displacement difference between the calibration radar and the tower base of the wind turbine is measured, and the height of the calibration radar is adjusted according to the vertical displacement difference, so that the installation plane of the calibration radar coincides with the installation plane of the tower base. It should be understood that the installation plane of the calibration radar and the installation plane of the tower base may not coincide, as long as the two planes are parallel, that is, there is a fixed Z coordinate difference between the two. However, in order to facilitate the adjustment of the initial Z coordinates of the two GPSs, the installation plane of the calibration radar can be overlapped with the installation plane of the tower base during installation.

[0060] like Figure 5 As shown in the figure, the calibrated radar can be adjusted to obtain the 3D point cloud image of the blade tip and the tower in real time, and the point coordinates X of the blade tip can be used to calculate the 3D point cloud image of the blade tip and the tower. A = 0, determine the distance L1 between the blade tip A and the calibration radar, the distance L2 between the projection point B of the blade tip A on the tower wall and the calibration radar, the angle β between the line between the blade tip A and the calibration radar and the tower base installation plane, and the angle α between the line between the projection point B and the calibration radar and the tower base installation plane. Combining these parameters, the distance value to the tower wall can be calculated, and the specific calculation formula is as follows:

[0061] B t =L1cosβ-L2cosα.

[0062] By calibrating the radar, we can obtain the 3D point cloud images of the blade tip and the tower. Considering factors such as yaw and blade tip height, the distance value calculated by the obtained 3D point cloud image has higher calculation accuracy. By comparing the blade clearance value A measured by the video clearance radar at the same time point t and the distance value B measured by the calibration radar t , the blade clearance monitoring error of the evaluated wind turbine is more accurate.

[0063] like Figure 2 The flowchart of the wind turbine blade clearance monitoring alarm threshold optimization method shown in the figure includes:

[0064] Step S1, obtaining a blade clearance value measured by a clearance monitoring device within a specified time range, and a distance value from a blade tip to a tower wall of a wind turbine generator set obtained by synchronous measurement of a calibration radar;

[0065] Step S2, calculating the clearance difference corresponding to different time points within a specified time range according to the corresponding blade clearance value and distance value;

[0066] Step S3: Count the average of the headroom differences within a specified time range, and optimize the preset alarm threshold according to the average of the headroom differences.

[0067] Specifically, first, the blade clearance value of the wind turbine can be monitored in real time through existing clearance monitoring equipment, such as millimeter wave radar, laser radar, video clearance radar, etc. At the same time, the distance value from the blade tip to the tower wall of the wind turbine is synchronously measured by the installed calibration radar. Then, the blade clearance value measured by the clearance monitoring equipment at the same time point is compared with the distance value measured by the calibration radar to determine the clearance difference between the clearance monitoring equipment and the calibration radar at that time point. Finally, by performing statistical analysis on the clearance differences corresponding to all time points within the specified time range, the mean clearance difference within the time range is determined, and the preset alarm threshold of the wind turbine can be optimized through the mean clearance difference, thereby eliminating the influence of factors such as cabin glass fiber flatness, cabin inclination, clearance equipment installation angle, and tower inclination on clearance alarm monitoring. The specific optimization calculation formula of the alarm threshold is as follows:

[0068]

[0069] Among them, C0 is the preset alarm threshold.

[0070] A method for monitoring the clearance of blades of a wind turbine generator system, comprising:

[0071] The above-mentioned wind turbine blade clearance monitoring alarm threshold optimization method is adopted to optimize the alarm threshold corresponding to the wind turbine.

[0072] Specifically, the above-mentioned optimization method can be used to optimize the alarm threshold corresponding to the clearance monitoring in real time. The blade clearance value measured by the video clearance monitoring device is then compared with the optimized alarm threshold. If it is less than the optimized alarm threshold, an alarm signal is issued, otherwise, no alarm signal is issued. Since the influence of factors such as the flatness of the cabin glass fiber, the cabin inclination, the installation angle of the clearance equipment and the inclination of the tower on the clearance alarm monitoring is eliminated, the clearance monitoring alarm of the wind turbine can be made more accurate, effectively reducing the power generation loss caused by the false clearance alarm triggering the unit protection mode.

[0073] In this embodiment, optionally, it further includes:

[0074] The vertical distance between the clearance monitoring device and the blade tip plane is measured, and the installation angle of the clearance monitoring device is adjusted according to the distance value measured by the calibration radar.

[0075] Specifically, while optimizing the alarm threshold, the corresponding angle adjustment value can be calculated based on the distance from the blade tip to the tower wall measured by the calibration radar and the vertical distance between the clearance monitoring device and the blade tip plane. The installation angle of the video clearance device is then manually adjusted according to the angle adjustment value to eliminate the impact of the clearance device installation angle on the clearance alarm monitoring, further improving the accuracy of the clearance monitoring alarm.

[0076] like Figure 3 The system block diagram of the wind turbine blade clearance monitoring error evaluation system shown in FIG. 1 includes:

[0077] An acquisition module is configured to acquire a blade clearance value measured by a clearance monitoring device within a specified time range, and a distance value from a blade tip to a tower wall of a wind turbine generator set obtained by synchronous measurement of a calibration radar;

[0078] A calculation module, configured to calculate the clearance difference corresponding to different time points within a specified time range according to the corresponding blade clearance value and distance value;

[0079] The evaluation module is configured to calculate the mean value of the clearance difference within a specified time range and evaluate the blade clearance monitoring error of the wind turbine according to the mean value of the clearance difference.

[0080] Specifically, the evaluation system includes an acquisition module, a calculation module and an evaluation module, wherein the acquisition module can acquire existing clearance monitoring equipment, such as millimeter wave radar, laser radar, video clearance radar, etc., to monitor the blade clearance value of the wind turbine in real time. At the same time, the distance value from the blade tip to the tower wall of the wind turbine is synchronously measured by the installed calibration radar. The calculation module can compare the blade clearance value measured by the clearance monitoring device at the same time point with the distance value measured by the calibration radar, so as to determine the clearance difference between the clearance monitoring device and the calibration radar at that time point. The evaluation module can determine the mean clearance difference within the time range by statistically analyzing the clearance difference corresponding to all time points within the specified time range, and accurately evaluate the blade clearance monitoring error of the wind turbine through the mean clearance difference. At the same time, the clearance monitoring error at the current time point can also be accurately evaluated based on the clearance difference and blade clearance value corresponding to the time point.

[0081] like Figure 4 The system block diagram of the wind turbine blade clearance monitoring alarm threshold optimization system shown in the figure includes:

[0082] An acquisition module is configured to acquire a blade clearance value measured by a clearance monitoring device within a specified time range, and a distance value from a blade tip to a tower wall of a wind turbine generator set obtained by synchronous measurement of a calibration radar;

[0083] A calculation module, configured to calculate the clearance difference corresponding to different time points within a specified time range according to the corresponding blade clearance value and distance value;

[0084] The optimization module is configured to calculate the average value of the clearance difference within a specified time range and optimize the preset alarm threshold value based on the average value of the clearance difference.

[0085] Specifically, the optimization system includes an acquisition module, a calculation module and an optimization module. Among them, the acquisition module can obtain the existing clearance monitoring equipment to monitor the blade clearance value of the wind turbine in real time. At the same time, the calibration radar synchronously measures the distance value from the blade tip to the tower wall of the wind turbine. The calculation module can compare the blade clearance value measured by the clearance monitoring equipment at the same time point with the distance value measured by the calibration radar, so as to determine the clearance difference between the clearance monitoring equipment and the calibration radar at that time point. The optimization module can perform statistical analysis on the clearance difference corresponding to all time points within the specified time range, determine the average clearance difference within the time range, and optimize the preset alarm threshold of the wind turbine through the average clearance difference, thereby eliminating the influence of factors such as the flatness of the cabin glass fiber, the cabin inclination, the installation angle of the clearance equipment and the tower inclination on the clearance alarm monitoring.

[0086] A wind turbine blade clearance monitoring system, comprising:

[0087] The threshold optimization module is configured to use the above-mentioned wind turbine blade clearance monitoring alarm threshold optimization method to optimize the alarm threshold corresponding to the wind turbine.

[0088] Specifically, the monitoring system includes a threshold optimization module and an alarm monitoring module. The threshold optimization module can use the above-mentioned optimization method to optimize the alarm threshold corresponding to the clearance monitoring in real time. The alarm monitoring module can compare the blade clearance value measured by the video clearance monitoring device with the optimized alarm threshold. If it is less than the optimized alarm threshold, an alarm signal is issued, otherwise, no alarm signal is issued. Since the influence of factors such as the flatness of the cabin glass fiber, the cabin inclination, the installation angle of the clearance equipment and the inclination of the tower on the clearance alarm monitoring is eliminated, the clearance monitoring alarm of the wind turbine can be made more accurate, effectively reducing the power generation loss caused by the false clearance alarm triggering the unit protection mode.

[0089] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A method for evaluating wind turbine blade clearance monitoring errors, characterized in that: include: Obtain the blade clearance value measured by the clearance monitoring equipment within a specified time range, and the distance value from the blade tip to the tower wall of the wind turbine obtained by synchronous measurement of the calibration radar; Calculate the clearance difference corresponding to different time points within a specified time range according to the corresponding blade clearance value and distance value; The mean clearance difference within the specified time range is calculated, and the blade clearance monitoring error of the wind turbine is evaluated based on the mean clearance difference.

2. The wind turbine blade clearance monitoring error assessment method according to claim 1 is characterized in that: Obtain the blade clearance value measured by the clearance monitoring equipment, including: Acquire multiple blade images continuously collected by the video clearance radar, and identify and locate the position coordinates of the target points in each blade image respectively; The Euclidean distance from each target point to the tower projection surface is calculated according to the corresponding position coordinates, and the minimum distance value is selected as the blade clearance value.

3. The wind turbine blade clearance monitoring error assessment method according to claim 1, characterized in that: Obtaining a distance value measured by the calibration radar, including: Obtain the blade pitch angle and nacelle yaw angle of the wind turbine in real time; When the blade pitch angle reaches a preset angle, the calibration radar is placed on the extension line of the direction indicated by the yaw angle of the nacelle, and the vertical displacement difference between the calibration radar and the tower base of the wind turbine is adjusted.

4. A method for optimizing the blade clearance monitoring alarm threshold of a wind turbine generator set, characterized in that: include: Obtain the blade clearance value measured by the clearance monitoring equipment within a specified time range, and the distance value from the blade tip to the tower wall of the wind turbine obtained by synchronous measurement of the calibration radar; Calculate the clearance difference corresponding to different time points within a specified time range according to the corresponding blade clearance value and distance value; Count the average of the clearance difference within the specified time range, and optimize the preset alarm threshold based on the average of the clearance difference.

5. A method for monitoring the clearance of blades of a wind turbine generator set, characterized in that: include: The wind turbine blade clearance monitoring alarm threshold optimization method as claimed in claim 4 is adopted to optimize the alarm threshold corresponding to the wind turbine.

6. The wind turbine blade clearance monitoring method according to claim 5, characterized in that: Also includes: The vertical distance between the clearance monitoring device and the blade tip plane is measured, and the installation angle of the clearance monitoring device is adjusted according to the distance value measured by the calibration radar.

7. A wind turbine blade clearance monitoring error assessment system, characterized in that: include: An acquisition module is configured to acquire a blade clearance value measured by a clearance monitoring device within a specified time range, and a distance value from a blade tip to a tower wall of a wind turbine generator set obtained by synchronous measurement of a calibration radar; A calculation module, configured to calculate the clearance difference corresponding to different time points within a specified time range according to the corresponding blade clearance value and distance value; The evaluation module is configured to calculate the mean value of the clearance difference within a specified time range and evaluate the blade clearance monitoring error of the wind turbine according to the mean value of the clearance difference.

8. A wind turbine blade clearance monitoring alarm threshold optimization system, characterized in that: include: An acquisition module is configured to acquire a blade clearance value measured by a clearance monitoring device within a specified time range, and a distance value from a blade tip to a tower wall of a wind turbine generator set obtained by synchronous measurement of a calibration radar; A calculation module, configured to calculate the clearance difference corresponding to different time points within a specified time range according to the corresponding blade clearance value and distance value; The optimization module is configured to calculate the average value of the clearance difference within a specified time range and optimize the preset alarm threshold value based on the average value of the clearance difference.

9. A wind turbine blade clearance monitoring system, characterized in that: include: The threshold optimization module is configured to optimize the alarm threshold corresponding to the wind turbine using the wind turbine blade clearance monitoring alarm threshold optimization method as described in claim 4.

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