Method and System for Clearance Monitoring of Wind Turbines Based on Millimeter Waves in the Machine Cabin

Abstract

The present invention discloses a method and system for monitoring the clearance of a wind turbine based on millimeter waves in the nacelle, which reads the fault code and clearance value L of the millimeter wave rangefinder in real time 实测 , under the condition that the ranging value is normal, it is judged whether the blade is operating in the safe clearance area or the non-safe clearance area through the ranging value, and the sizes of the safe clearance value L1, the low-speed pitch clearance value L2, the medium-speed pitch clearance value L3, and the shutdown clearance value L4 are compared, and then how to pitch or shut down is determined to ensure the safe operation of the wind turbine; when it is found that the ranging value data is abnormal, the specific operation condition of the millimeter wave rangefinder is judged through the fault code of the millimeter wave rangefinder, so as to improve the reliability of the whole clearance monitoring system. The present invention can meet the highly adaptable monitoring in various bad weather and complex environments, has high reliability and accuracy, simple calibration, low cost at the same time, and is convenient for installation and later maintenance.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power generation, and in particular to a method and system for monitoring the clearance of a wind turbine based on millimeter waves in the nacelle. Background Art

[0002] With the development of wind power generation technology, the blades of wind turbines are getting longer and longer, which means the blades are getting softer and deforming greatly during rotation, and there is a possibility of hitting the tower barrel and causing danger. Therefore, it is necessary to monitor the distance between the blades and the tower barrel of the wind turbine in real time, that is, the clearance distance from the lower tip of the blade to the outer wall of the tower barrel.

[0003] Currently, the more common practice in the industry for monitoring the clearance between the blade and the tower barrel is to install a laser rangefinder at the nacelle position and dynamically monitor the blade clearance by following the real-time yaw of the nacelle. However, the laser has a short wavelength and poor penetration performance, resulting in poor anti-interference ability in bad weather such as rain, snow, and fog, and can only meet the monitoring in normal weather. Compared with the laser, the millimeter wave has a longer wavelength and stronger penetration performance, and has a strong anti-interference ability in bad weather such as rain, snow, and fog, and can meet the clearance monitoring in various bad weathers.

[0004] If the clearance monitoring sensor is arranged at a position on the outer wall of the tower barrel at the same height as the lower tip of the blade, because the installation height of the millimeter wave rangefinder is the height of the lower tip, at least 20 meters from the ground, professional equipment such as a crane and a hanging basket is required for installation and subsequent maintenance, which is very inconvenient, and the installation cost and maintenance cost are very high.

[0005] In addition, some other clearance monitoring methods are studied as follows:

[0006] If the clearance monitoring sensor is installed at the tip of the blade, first, it is not convenient for installation and subsequent maintenance, and the cost is high; second, because the linear velocity of the blade is very large, comparable to that of a high-speed train, the sensor is extremely easy to be thrown out due to the huge centrifugal force, resulting in sensor damage and endangering the safety of personnel around the wind turbine; third, the sensor installed at the tip of the blade will affect the aerodynamic performance of the blade. If the clearance monitoring sensor is arranged at the root position inside the blade and the blade clearance is indirectly measured by measuring the deformation of the blade, first, only the middle position of the blade can be monitored, and the tip cannot be monitored; second, it is necessary to accurately obtain the relationship between the blade deformation and the load, and further obtain the blade clearance through the calibration relationship between the load and the blade clearance, which is very difficult and indirect for the actual site, and the error will be very large and it is difficult to be accurate, while the requirement for blade clearance monitoring is relatively accurate. If methods such as cameras or video monitoring are used, even in normal weather, the monitoring effect at night is poor, the blade cannot be accurately identified, and the strong sunlight at noon during the day will also affect the monitoring effect. In case of bad weather such as rain, snow, and fog, the effect will be even worse. Summary of the Invention

[0007] The first object of the present invention is to overcome the disadvantages and deficiencies of the existing blade clearance monitoring technology for wind turbines, and to provide a method for monitoring the clearance of wind turbines based on millimeter waves in the nacelle, which can meet the highly adaptable monitoring in various harsh weather and complex environments, has high reliability and accuracy, simple calibration, low cost, is easy to install and maintain in the later stage, and has great practical significance.

[0008] The second object of the present invention is to provide a system for monitoring the clearance of wind turbines based on millimeter waves in the nacelle.

[0009] The first object of the present invention is achieved by the following technical solutions: For the method for monitoring the clearance of wind turbines based on millimeter waves in the nacelle, first, through simulation calculation, determine the safe clearance value L1 from the lower tip of the blade to the outer wall of the tower, the low-speed pitch clearance value L2, the medium-speed pitch clearance value L3, and the shutdown clearance value L4 during the operation of the wind turbine; secondly, according to the Pythagorean theorem of a triangle, calculate the angle of the installation tooling of the millimeter wave rangefinder through the height of the lower tip of the blade, the clearance value from the lower tip of the blade to the outer wall of the tower, and the distance between the installation position of the millimeter wave rangefinder and the lower tip of the blade; finally, install the millimeter wave rangefinder on the nacelle, and adjust the millimeter wave rangefinder to the previously calculated angle through the inclination sensor integrated inside the millimeter wave rangefinder, ensuring that the millimeter wave rangefinder is adjusted to the clearance monitoring area near the lower tip of the blade, that is, the installation and positioning of the rangefinder are completed. Moreover, because the millimeter wave rangefinder is installed on the nacelle and yaws together with the nacelle, only one unit is required to achieve full-area non-blind monitoring, ensuring the safe operation of the wind turbine. In addition, since the monitoring range of the millimeter wave rangefinder is a fan-shaped area, it can monitor a section of the blade from the lower tip of the blade towards the root of the blade, and can avoid false alarms of clearance caused by non-blade behaviors, thereby improving the accuracy of clearance alarms;

[0010] After installation, when the wind turbine is operating, the following method is used to perform real-time monitoring and control of the blade clearance:

[0011] If the clearance value L measured by the millimeter wave rangefinder 实测 > the safe clearance value L1, at this time the blade is operating in the safe clearance area and no treatment is done, and the wind turbine continues to operate normally;

[0012] If the clearance value L measured by the millimeter wave rangefinder 实测 ≤ the safe clearance value L1, at this time the blade is operating in the non-safe clearance area under the action of strong wind. Further compare the clearance value L measured by the millimeter wave rangefinder 实测 with the simulated low-speed pitch clearance value L2, medium-speed pitch clearance value L3, and shutdown clearance value L4, and process according to the following method:

[0013] If the low-speed pitch clearance value L2 < the clearance value L measured by the millimeter wave rangefinder 实测≤Safety clearance value L1, the wind turbine increases the pitch angle through low-speed pitch control to increase the clearance value to ensure the safe operation of the wind turbine;

[0014] If the medium-speed pitch control clearance value L3 < the clearance value L measured by the millimeter-wave rangefinder 实测 ≤Low-speed pitch control clearance value L2, the wind turbine increases the pitch angle through medium-speed pitch control to increase the clearance value to ensure the safe operation of the wind turbine;

[0015] If the shutdown clearance value L4 < the clearance value L measured by the millimeter-wave rangefinder 实测 ≤Medium-speed pitch control clearance value L3, the wind turbine increases the pitch angle through high-speed pitch control to increase the clearance value to ensure the safe operation of the wind turbine;

[0016] If the clearance value L measured by the millimeter-wave rangefinder 实测 ≤Shutdown clearance value L4, the blades are stopped by shutdown to ensure the safe operation of the wind turbine.

[0017] Furthermore, the millimeter-wave rangefinder is integrated with start-stop code and fault code. Since the clearance is large when the wind turbine is in the shutdown state and low-power operation, there is no problem of unsafe clearance. The start-stop code is added to control the opening and closing of the millimeter-wave rangefinder, so that the wind turbine can automatically shut down the millimeter-wave rangefinder through the start-stop code in the shutdown and low-power operation states, so as to extend the service life of the millimeter-wave rangefinder; the fault code is used to feedback whether the millimeter-wave rangefinder is operating normally, and can understand the operation of the millimeter-wave rangefinder in real time, and can feedback the fault conditions of different millimeter-wave rangefinders in time when data anomalies occur.

[0018] Furthermore, an inclination sensor is configured inside the millimeter-wave rangefinder to determine the angle of the millimeter-wave rangefinder and ensure that the rangefinder is adjusted to the clearance monitoring area near the lower blade tip.

[0019] Furthermore, a positioning laser is integrated inside the millimeter-wave rangefinder. The positioning laser can be controlled to be turned on and off on the tower base control cabinet of the wind turbine. It can be mutually verified with the inclination sensor during installation, and when checking whether the angle of the millimeter-wave rangefinder is deviated later, the operation can be carried out on the tower base control cabinet without climbing into the nacelle after shutdown.

[0020] The second object of the present invention is achieved by the following technical solutions: A clearance monitoring system for a wind turbine based on millimeter waves in the nacelle, which is applied to the above-mentioned clearance monitoring method for a wind turbine based on millimeter waves in the nacelle. This system reads the parameters related to the clearance of the wind turbine from the PLC control system of the wind turbine, and makes a logical judgment on the read parameters. When the read parameters meet the access conditions for blade clearance monitoring, the entire clearance monitoring system will automatically switch to the blade clearance monitoring mode, control the start-stop code of the millimeter wave rangefinder to open, and make the millimeter wave rangefinder in the working state. Otherwise, it will control the start-stop code of the millimeter wave rangefinder to remain closed. In this way, when the wind turbine is in the shutdown state and there is no clearance safety problem during low-power operation, the millimeter wave rangefinder does not work, which prolongs the service life of the millimeter wave rangefinder. Among them, in the blade clearance monitoring mode, this system reads the fault code and clearance value L of the millimeter wave rangefinder in real time 实测 , and transmits them to the PLC control system of the wind turbine. When the ranging value is normal, this system judges whether the blade is operating in a safe clearance area or an unsafe clearance area through the ranging value, and compares the sizes of the safe clearance value L1, the low-speed pitch clearance value L2, the medium-speed pitch clearance value L3, and the shutdown clearance value L4, and then decides how to pitch or shut down to ensure the safe operation of the wind turbine; when it is found that the ranging value data is abnormal, this system will judge the specific operation situation of the millimeter wave rangefinder through the fault code of the millimeter wave rangefinder, thereby improving the reliability of the entire clearance monitoring system.

[0021] Further, the parameters related to the clearance include the operating state, power, wind speed, wind turbine speed, pitch angle, and wind turbine azimuth angle of the wind turbine.

[0022] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0023] 1. Compared with lasers, millimeter wave rangefinders have longer wavelengths, stronger penetrability, stronger resistance to interference from harsh weather such as rain, snow, and fog, and better adaptability to complex environments.

[0024] 2. Compared with lasers that can only monitor one point, several points, or a surface, millimeter wave rangefinders can monitor a certain fan-shaped area, so they can monitor a relatively long section of the blade from the tip to the root, and the accuracy of the test results is higher.

[0025] 3. Compared with photographing and video monitoring, millimeter wave rangefinders will not have a worse effect at night or in low light conditions, and can achieve the same effect during the day and at night.

[0026] 4. Installing the millimeter wave rangefinder in the nacelle position reduces the installation and maintenance difficulty and cost compared with the method of installing it at the lower tip of the blade.

[0027] 5. The millimeter wave rangefinder yaws together with the nacelle, and only one millimeter wave rangefinder can be used to achieve real-time monitoring, reducing costs.

[0028] 6. The present invention adopts a direct monitoring method. Compared with some indirect measurement methods (such as inferring the change in clearance by inferring the load change through blade deformation, etc.), the data collected by it does not require conversion and calibration of multiple physical quantities, and can be directly judged, with a simple method and accurate results, reducing the computing burden of the collector.

[0029] 7. The present invention adopts different control means for different clearance areas of the safety clearance value L1, low-speed pitch clearance value L2, medium-speed pitch clearance value L3, and shutdown clearance value L4, maximizing power generation while ensuring the safety of the wind turbine;

[0030] 8. The millimeter-wave rangefinder of the present invention integrates a start-stop code, which is disconnected when the wind turbine is shut down or operating at low power, extending the service life of the millimeter-wave rangefinder and reducing costs.

[0031] 9. The millimeter-wave rangefinder of the present invention integrates an inclination sensor. When installed, the inclination adjustment is simple and convenient, and because of the integrated one-piece design, the accuracy of inclination adjustment is higher.

[0032] 10. The millimeter-wave rangefinder of the present invention integrates a positioning laser. When installed, it can verify with the inclination sensor mutually. At the same time, when checking whether the angle is deviated later, only the tower base control cabinet needs to be operated, without climbing up the nacelle after shutdown, which is convenient and safe.

[0033] 11. The millimeter-wave rangefinder of the present invention can output a fault code, enabling real-time understanding of the operating state of the millimeter-wave rangefinder and timely feedback on the working condition of the clearance monitoring system. Brief Description of the Drawings

[0034] Figure 1 It is a schematic diagram of the equipment for wind turbine clearance monitoring. Detailed Embodiment

[0035] The present invention will be further described in detail below in conjunction with the embodiments and the drawings, but the embodiments of the present invention are not limited thereto.

[0036] Embodiment 1

[0037] As Figure 1 shown, the nacelle 3 of the wind turbine is installed on the top of the tower barrel 5, the PLC control system 1 of the wind turbine is installed in the tower base control cabinet of the tower barrel 5, and the wind wheel composed of three blades 4 rotates clockwise after absorbing wind energy.

[0038] This embodiment provides a method for wind turbine clearance monitoring based on millimeter waves in the nacelle, and the specific situation is as follows:

[0039] First, through simulation calculations, determine the safety clearance value L1 from the lower tip of blade 4 to the outer wall of the tower 5, the low-speed pitch clearance value L2, the medium-speed pitch clearance value L3, and the stop clearance value L4 during the operation of the wind turbine; secondly, according to the Pythagorean theorem of a triangle, calculate the angle of the millimeter-wave rangefinder installation tooling through the height of the lower tip of blade 4, the clearance value from the lower tip to the outer wall of the tower 5, and the distance between the installation position of the millimeter-wave rangefinder and the lower tip; and the millimeter-wave rangefinder yaws together with the nacelle, and only one millimeter-wave rangefinder 2 is required to achieve real-time monitoring; the millimeter-wave rangefinder 2 is adjusted to the pre-calculated angular position through the built-in inclination sensor inside the millimeter-wave rangefinder 2, ensuring that the millimeter-wave rangefinder is adjusted to the clearance monitoring area near the lower tip of the blade, that is, the installation and positioning of the rangefinder are completed. And because the monitoring range of the millimeter-wave rangefinder 2 is a fan-shaped area, it can monitor a section of the blade from the lower tip of blade 4 towards the blade root, and can avoid false alarms of clearance caused by non-blade behaviors, thereby improving the accuracy of clearance alarms.

[0040] After installation, when the wind turbine is operating, the blade clearance is monitored and controlled in real time according to the following method:

[0041] If the clearance value L measured by the millimeter-wave rangefinder 实测 > the safety clearance value L1, at this time the blade is operating in the safe clearance area and no treatment is done, and the wind turbine continues to operate normally;

[0042] If the clearance value L measured by the millimeter-wave rangefinder 实测 ≤ the safety clearance value L1, at this time the blade is operating in the non-safe clearance area under the action of strong wind, and further compare the clearance value L measured by the millimeter-wave rangefinder 实测 with the simulated low-speed pitch clearance value L2, medium-speed pitch clearance value L3, and stop clearance value L4, and process according to the following method:

[0043] If the low-speed pitch clearance value L2 < the clearance value L measured by the millimeter-wave rangefinder 实测 ≤ the safety clearance value L1, then the wind turbine increases the pitch angle through low-speed pitching to increase the clearance value to ensure the safe operation of the wind turbine;

[0044] If the medium-speed pitch clearance value L3 < the clearance value L measured by the millimeter-wave rangefinder 实测 ≤ the low-speed pitch clearance value L2, then the wind turbine increases the pitch angle through medium-speed pitching to increase the clearance value to ensure the safe operation of the wind turbine;

[0045] If the stop clearance value L4 < the clearance value L measured by the millimeter-wave rangefinder 实测 ≤ the medium-speed pitch clearance value L3, then the wind turbine increases the pitch angle through high-speed pitching to increase the clearance value to ensure the safe operation of the wind turbine;

[0046] If the clearance value L measured by the millimeter-wave rangefinder 实测 ≤ the shutdown clearance value L4, the blades are stopped by shutdown to ensure the safe operation of the wind turbine generator set.

[0047] Furthermore, the millimeter-wave rangefinder 2 is integrated with start-stop codes and fault codes. Since the clearance is large when the wind turbine generator set is in the shutdown state and running at low power, and there is no problem of unsafe clearance, start-stop codes are added to control the opening and closing of the millimeter-wave rangefinder 2, so that when the wind turbine generator set is in the shutdown and low-power operation states, the millimeter-wave rangefinder 2 can be automatically shut down through the start-stop codes to extend the service life of the millimeter-wave rangefinder 2; the fault codes are used to feedback whether the millimeter-wave rangefinder 2 is operating normally, and the operation status of the millimeter-wave rangefinder 2 can be understood in real time. When data anomalies occur, the fault conditions of different millimeter-wave rangefinders 2 can be feedback in time.

[0048] Furthermore, an inclination sensor is configured inside the millimeter-wave rangefinder 2 to determine the angle of the millimeter-wave rangefinder 2 and ensure that the rangefinder is adjusted to the clearance monitoring area near the lower blade tip. Compared with using an external inclination sensor to adjust the angle, it not only saves a lot of time and workload, but also is more accurate than an external inclination sensor when adjusting the angle of the millimeter-wave rangefinder, and better improves the accuracy of the angle adjustment of the millimeter-wave rangefinder.

[0049] Furthermore, a positioning laser is integrated inside the millimeter-wave rangefinder 2, which can be mutually verified with the inclination sensor during installation, and the positioning laser can be controlled to be turned on and off in the tower base control cabinet of the wind turbine generator set. During subsequent maintenance, operations can be performed in the tower base control cabinet, and there is no need to climb into the nacelle after shutdown to check whether the angle of the millimeter-wave rangefinder 2 is deviated.

[0050] Embodiment 2

[0051] This embodiment provides a nacelle millimeter-wave based wind turbine clearance monitoring system, which can implement the nacelle millimeter-wave based wind turbine clearance monitoring method described in Embodiment 1. This system can be integrated into the PLC control system 1 of the wind turbine or separated separately. It mainly reads the parameters related to the clearance of the wind turbine from the PLC control system 1 of the wind turbine, including the operating state, power, wind speed, wind turbine rotational speed, pitch angle, and wind turbine azimuth angle of the wind turbine, etc., and makes logical judgments on the read parameters. When the read parameters meet the access conditions for blade clearance monitoring, the entire clearance monitoring system will automatically switch to the blade clearance monitoring mode, control the start-stop code of the millimeter-wave rangefinder 2 to open, and make the millimeter-wave rangefinder 2 in the working state. Otherwise, it will control the start-stop code of the millimeter-wave rangefinder 2 to remain closed. In this way, when the wind turbine is in the shutdown state and there is no clearance safety problem during low-power operation, the millimeter-wave rangefinder 2 does not work, extending the service life of the millimeter-wave rangefinder 2. Among them, in the blade clearance monitoring mode, the system reads the fault code and clearance value L of the millimeter-wave rangefinder 2 in real time 实测 , and transmits them to the PLC control system 1 of the wind turbine. When the ranging value is normal, the system judges whether the blade is operating in the safe clearance area or the non-safe clearance area through the ranging value, and compares the sizes of the safe clearance value L1, low-speed pitch clearance value L2, medium-speed pitch clearance value L3, and shutdown clearance value L4, and then decides how to pitch or shut down to ensure the safe operation of the wind turbine. When it is found that the ranging value data is abnormal, the system will judge the specific operation situation of the millimeter-wave rangefinder through the fault code of the millimeter-wave rangefinder 2, thereby improving the reliability of the entire clearance monitoring system.

[0052] The above-described embodiments are only the preferred embodiments of the present invention, and do not limit the scope of implementation of the present invention. Therefore, all changes made according to the shape and principle of the present invention should be covered within the protection scope of the present invention.

Claims

1. A method for monitoring the clearance of a wind turbine based on millimeter waves in the nacelle, characterized in that: First, through simulation calculations, determine the safe clearance value L1 from the lower tip of the blade to the outer wall of the tower, the low-speed pitch clearance value L2, the medium-speed pitch clearance value L3, and the shutdown clearance value L4 during the operation of the wind turbine; secondly, according to the Pythagorean theorem of a triangle, calculate the installation angle of the millimeter-wave rangefinder through the height of the lower tip of the blade, the clearance value from the lower tip of the blade to the outer wall of the tower, and the distance between the installation position of the millimeter-wave rangefinder and the lower tip of the blade; finally, install the millimeter-wave rangefinder on the nacelle, and adjust the millimeter-wave rangefinder to the previously calculated angle through the inclination sensor integrated inside the millimeter-wave rangefinder, ensuring that the millimeter-wave rangefinder is adjusted to the clearance monitoring area near the lower tip of the blade, thus completing the installation and positioning of the rangefinder. Moreover, since the millimeter-wave rangefinder is installed on the nacelle and yaws together with the nacelle, only one is needed to achieve full-area non-blind-zone monitoring, ensuring the safe operation of the wind turbine. In addition, since the monitoring range of the millimeter-wave rangefinder is a fan-shaped area, it can monitor a section of the blade from the lower tip of the blade towards the root of the blade, and can avoid false alarms of clearance caused by non-blade behaviors, thereby improving the accuracy of clearance alarms; After installation, during the operation of the wind turbine, the blade clearance is monitored and controlled in real time according to the following method: If the clearance value L measured by the millimeter-wave rangefinder 实测 > the safety clearance value L1, at this time the blade operates in the safe clearance area without any treatment, and the wind turbine continues to operate normally; If the clearance value L measured by the millimeter-wave rangefinder 实测 ≤ the safety clearance value L1, at this time the blade operates in the non-safe clearance area under the action of strong wind. Further compare the clearance value L measured by the millimeter-wave rangefinder 实测 with the low-speed pitch clearance value L2, medium-speed pitch clearance value L3, and stop clearance value L4 obtained by simulation, and process them according to the following method: If the low-speed pitch clearance value L2 < the clearance value L measured by the millimeter-wave rangefinder 实测 ≤ the safety clearance value L1, the wind turbine increases the pitch angle through low-speed pitching to increase the clearance value to ensure the safe operation of the wind turbine; If the net clearance value L3 of medium-speed pitch < the net clearance value L measured by the millimeter-wave rangefinder 实测 ≤ the net clearance value L2 of low-speed pitch, the wind turbine increases the pitch angle through medium-speed pitching to increase the net clearance value to ensure the safe operation of the wind turbine; If the shutdown clearance value L4 < the clearance value L measured by the millimeter-wave rangefinder 实测 ≤ the medium-speed pitch clearance value L3, the wind turbine increases the pitch angle through high-speed pitching to increase the clearance value to ensure the safe operation of the wind turbine; If the clearance value L measured by the millimeter-wave rangefinder 实测 ≤ the shutdown clearance value L4, the blades are stopped by shutdown to ensure the safe operation of the wind turbine.

2. The method for monitoring the clearance of a wind turbine based on millimeter waves in the nacelle according to claim 1, characterized in that: The millimeter-wave rangefinder is integrated with start / stop codes and fault codes. Since the clearance is large during the shutdown state and low-power operation of the wind turbine, and there is no problem of unsafe clearance, start / stop codes are added to control the opening and closing of the millimeter-wave rangefinder, enabling the wind turbine to automatically shut down the millimeter-wave rangefinder through the start / stop codes during the shutdown and low-power operation states, so as to extend the service life of the millimeter-wave rangefinder; the fault codes are used to feedback whether the millimeter-wave rangefinder is operating normally, enabling real-time understanding of the operation of the millimeter-wave rangefinder and timely feedback of the fault conditions of different millimeter-wave rangefinders in case of abnormal data.

3. The method for monitoring the clearance of a wind turbine based on millimeter waves in the nacelle according to claim 1, characterized in that: The millimeter-wave rangefinder is internally equipped with an inclination sensor to determine the angle of the millimeter-wave rangefinder and ensure that the rangefinder is adjusted to the clearance monitoring area near the lower tip of the blade.

4. The method for monitoring the clearance of a wind turbine based on millimeter waves in the nacelle according to claim 1, characterized in that: The millimeter-wave rangefinder is internally integrated with a positioning laser, which can be controlled to be turned on and off on the tower base control cabinet of the wind turbine. It can be mutually verified with the inclination sensor during installation, and subsequent operations to check whether the angle of the millimeter-wave rangefinder is deviated can be carried out on the tower base control cabinet without having to climb onto the nacelle after shutdown.

5. A system for monitoring the clearance of a wind turbine based on millimeter waves in the nacelle, characterized in that, Applied to the nacelle millimeter-wave-based wind turbine clearance monitoring method according to any one of claims 1 to 4, the system reads the parameters related to the wind turbine clearance from the PLC control system of the wind turbine, and makes a logical judgment on the read parameters. When the read parameters meet the blade clearance monitoring access conditions, the entire clearance monitoring system will automatically switch to the blade clearance monitoring mode, control the start-stop code of the millimeter-wave rangefinder to open, and make the millimeter-wave rangefinder in the working state. Otherwise, control the start-stop code of the millimeter-wave rangefinder to remain closed. This can make the millimeter-wave rangefinder not work when the wind turbine is in the shutdown state and there is no clearance safety problem during low-power operation, extending the service life of the millimeter-wave rangefinder. Among them, in the blade clearance monitoring mode, the system reads the fault code and clearance value L of the millimeter-wave rangefinder in real time 实测 , and transmits it to the PLC control system of the wind turbine. Under normal ranging value conditions, the system judges whether the blade is operating in a safe clearance area or an unsafe clearance area through the ranging value, and compares the sizes of the safe clearance value L1, low-speed pitch clearance value L2, medium-speed pitch clearance value L3, and shutdown clearance value L4, and then decides how to pitch or shut down to ensure the safe operation of the wind turbine. When it is found that the ranging value data is abnormal, the system will judge the specific operation situation of the millimeter-wave rangefinder through the fault code of the millimeter-wave rangefinder, thereby improving the reliability of the entire clearance monitoring system.

6. The system for monitoring the clearance of a wind turbine based on millimeter waves in the nacelle according to claim 5, characterized in that: The parameters related to the clearance include the operating state, power, wind speed, wind turbine speed, pitch angle, and wind turbine azimuth angle of the wind turbine.

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