A wind turbine tower clearance monitoring system and method based on a ring identification device

Abstract

This invention provides a wind turbine tower clearance monitoring system and method based on a ring recognition device. The monitoring system includes: a camera device installed at the bottom of the nacelle shell, located between the tower and the blades; a ring recognition device composed of two or more arc-shaped recognition plates joined end to end, with a ring-shaped light strip installed on it; a control device installed on the ground and connected to the ring recognition device via a signal line; a central processing unit receiving light intensity data signals and image data monitored by the camera device via wired or wireless means, analyzing the image data and light intensity data signals, and determining whether the clearance value has reached a safe threshold; and a power supply providing power to the ring-shaped light strip in the ring recognition device and the control device. This application utilizes a ring recognition device for clearance monitoring, which is simple, efficient, and accurate, overcoming the shortcomings of existing monitoring methods such as complex calculations and large errors.

Description

Technical Field

[0001] This invention relates to the field of wind turbine operation status monitoring technology, and in particular to a wind turbine tower clearance monitoring system and method. Background Technology

[0002] The tower clearance of a wind turbine refers to the minimum distance between the blade tip and the tower as the blade passes through the tower during rotor rotation. As the capacity of individual wind turbines increases, along with rotor diameter and blade length, the clearance between the tower and the blades becomes increasingly crucial. Insufficient tower clearance can lead to the risk of blade collision with the tower. Therefore, real-time monitoring of the blade clearance is necessary to ensure the safe operation of wind turbines.

[0003] Currently, a mainstream technology for monitoring the clearance between wind turbine towers involves installing a camera at the bottom front of the nacelle to capture video images of the blades and tower. The distance between the blade tips and the tower is then determined by analyzing the pixel distances in the images. This method requires determining the orientation of the blades and locating the tower at the same height as the blade tips in the image. This process is complex and prone to significant errors. Furthermore, the video monitoring process is susceptible to the impact of poor visibility at night. Therefore, the reliability and accuracy of this technology require further improvement. Summary of the Invention

[0004] To address the shortcomings of current tower clearance video monitoring technology, this application provides a wind turbine tower clearance monitoring system and method based on a ring recognition device. In this application, clearance monitoring is performed based on a ring recognition device, which is simple, efficient, and accurate. It eliminates the need for complex calculations and real-time dynamic positioning of components such as blades and towers in existing monitoring methods, thereby solving the defects of complex calculations and large errors in existing monitoring methods.

[0005] The technical solution adopted to achieve the above-mentioned objectives of this invention is as follows:

[0006] A wind turbine tower clearance monitoring system based on a ring recognition device includes at least a camera device installed on the nacelle shell. The wind turbine tower clearance monitoring system includes:

[0007] The camera device is installed at the bottom of the nacelle shell and located between the tower and the blades, with the lens facing downwards;

[0008] The ring-shaped identification device is composed of two or more arc-shaped identification plates spliced ​​end to end. It is fixed to the ground with the tower as the center and has a ring-shaped light strip on it. The outer diameter of the ring-shaped identification device is D = 2R. Specifically, based on the tower tilt angle and the distance between the blade tip and the tower when the tower clearance is at its minimum, a straight line is drawn from the camera device and tangent to the outer surface of the blade tip facing the tower. This straight line is extended to intersect the plane of the upper surface of the ring-shaped identification device, obtaining the intersection point A. The plane of the upper surface of the ring-shaped identification device intersects the center line of the tower, obtaining the intersection point B. The distance between the intersection point A and the intersection point B is the radius R of the ring-shaped identification device.

[0009] The control device, installed on the ground and connected via a signal line ring recognition device, includes a light sensor, a data acquisition and transmission module, and a PLC control module. The light sensor monitors the ambient light intensity and transmits the detected data signal to the data acquisition and transmission module. The data acquisition and transmission module then transmits the light intensity data signal to the PLC control module and, via wired or wireless means, to the central processing unit. The PLC control module controls the opening and closing of the ring light strip based on the light intensity data.

[0010] The central processing unit receives light intensity data signals and image data monitored by the camera device via wired or wireless means, analyzes the image data and light intensity data signals, and determines whether the clearance value has reached the safety threshold.

[0011] The power supply provides power to the ring-shaped light strip and control device in the ring recognition device.

[0012] The arc-shaped recognition plate is divided into an inner ring and an outer ring. The ring-shaped light strip is installed in the inner ring, and the outer ring is coated with recognition paint. A pad is provided at the bottom of the ring-shaped light strip. The ring-shaped light strip and the pad are wrapped and fixed inside the protective shell. The protective shell and the pad are both made of two or more arc-shaped segments spliced ​​end to end. The protective shell consists of an upper shell made of light-transmitting material and a lower shell fixed to the arc-shaped recognition plate. The upper shell and the lower shell are connected and fixed by buckles.

[0013] A heating resistance wire is installed in the upper housing, and a PTC heater is installed on the lower surface of the outer ring of the arc-shaped identification plate. Both the heating resistance wire and the PTC heater are connected to the control device. The control device is equipped with a temperature sensor that can monitor the ambient temperature. The temperature sensor transmits the monitored temperature signal to the data acquisition and transmission module. The data acquisition and transmission module transmits the temperature signal to the PLC control module. The PLC control module controls the PTC heater and the heating resistance wire to turn on and off according to the temperature signal.

[0014] The lower shell has drainage outlets and fixing plates for fixing the lower shell. The fixing plates are connected and fixed to the arc-shaped identification plate by bolts. Both ends of the lower shell section are provided with overlapping joints for connecting to the adjacent lower shell sections.

[0015] The buckle consists of a semi-circular annular protrusion and an annular groove, which are connected by a reverse buckle. The semi-circular annular protrusion is located at the inner and outer edges of the bottom surface of the upper shell, and the annular groove is located at the inner and outer edges of the top surface of the lower shell.

[0016] The pad is laid on the upper surface of the inner cavity of the lower housing, and the pad has two rows of openings for weight reduction and heat dissipation; the ring light strip is laid on top of the pad, and the waterproof rating of the ring light strip is not lower than IP67 and the working voltage is not higher than 36V.

[0017] The ring-shaped identification device is composed of four identical arc-shaped identification plates spliced ​​end to end, and the protective shell and pad are also composed of four identical arc-shaped segments spliced ​​end to end.

[0018] The ring recognition device is fixed to the ground by a support base, which consists of an upper support plate, a lower support plate, and support ribs. The upper support plate is connected to the ring recognition plate by bolts, the lower support plate is located on the ground, and the support ribs are vertically connected between the upper support plate and the lower support plate.

[0019] This invention also provides a method for monitoring the clearance of wind turbine towers, comprising the following steps:

[0020] S1. Determine the outer diameter of the ring recognition device. The requirements for setting the outer diameter of the ring recognition device are as follows: Based on the tower tilt angle and the distance between the blade tip and the tower when the tower clearance is at its minimum, draw a straight line from the camera device that is tangent to the outer surface of the blade tip facing the tower. Extend this straight line to intersect the plane where the upper surface of the ring recognition device is located, and obtain the intersection point A. The plane where the upper surface of the ring recognition device is located intersects the center line of the tower, and obtain the intersection point B. The distance between the intersection point A and the intersection point B is the radius R of the ring recognition device. The outer diameter D of the ring recognition device is 2R.

[0021] S2. Install the ring recognition device at the bottom of the tower, with the center of the ring recognition device coinciding with the central axis of the tower; simultaneously install the camera device and the control device.

[0022] S3. The light sensor monitors the ambient light intensity in real time and transmits the monitoring data to the control device.

[0023] S4. The control device determines whether to turn the ring light strip on or off based on the magnitude of the light intensity data signal; when the light intensity is greater than the light intensity threshold, the ring light strip is turned off; when the light intensity is less than or equal to the light intensity threshold, the ring light strip is turned on to ensure high visibility even in low-light environments.

[0024] S5. The camera device captures images of the tower in front of the impeller side in real time and transmits the image data to the central processing unit via wired or wireless means.

[0025] S6. The central processing unit stores, analyzes, and judges the received images. The analysis and judgment methods are as follows:

[0026] S6.1 The central processing unit analyzes the image. If the light intensity data signal received by the central processing unit is greater than the light intensity threshold, the ring recognition device in the image is identified based on the color characteristics and circular features of the ring recognition plate. If the light intensity data signal received by the central processing unit is less than or equal to the light intensity threshold, the ring recognition device in the image is identified based on the brightness characteristics and circular features of the ring light strip.

[0027] S6.2 The central processing unit compares and analyzes frame by frame of images in real time and continuously. If it finds that a certain position in the image of the ring recognition device in front of the tower on one side of the impeller is interrupted or obstructed two or more times, and the time interval between two adjacent obstructions is an integer multiple of 20 / N seconds, it indicates that the tower clearance has reached the safety threshold, and a warning signal is issued; where N is the impeller rotation speed N r / min obtained by the central processing unit from the main control system.

[0028] In step S4, when the ambient temperature is lower than the temperature threshold, the control device activates the heating function of the heating resistance wire inside the protective shell and the heating function of the PTC heater on the lower surface of the outer ring of the ring recognition plate to prevent the protective shell of the ring light strip and the outer ring of the ring recognition plate from being covered by ice and snow, so as to ensure the recognizability of the ring recognition device.

[0029] Compared with the prior art, the technical solution provided by the present invention has the following advantages:

[0030] 1. The ring identification device consists of four identical arc-shaped identification plates, which facilitates the disassembly, transportation, and installation of the ring identification device, and also makes it easier for staff to transport materials and tools inside and outside the wind turbine.

[0031] 2. The ring recognition device is equipped with a ring light strip, which can be turned on or off according to the intensity of ambient light. When the ambient light is good, turning off the ring light strip can save energy; when the ambient light is poor at night or on rainy days, turning on the ring light strip can ensure the recognition accuracy of the ring recognition device.

[0032] 3. The lower housing of the ring-shaped light strip protective shell is equipped with a drainage hole to prevent moisture from accumulating in the lower housing.

[0033] 4. The lower housing of the ring-shaped light strip protective shell has a groove, and the upper housing of the ring-shaped light strip protective shell has a protrusion. The two fit together to quickly complete the installation of the lower and upper housings of the ring-shaped light strip protective shell without the need for bolts.

[0034] 5. When the ambient temperature is low, the heating function of the resistance wire inside the upper housing of the ring light strip protective shell and the heating function of the PTC heater on the lower surface of the outer ring of the ring recognition plate can be turned on to prevent the upper housing of the ring light strip protective shell and the outer ring of the ring recognition plate from being covered by ice and snow, so as to ensure the recognizability of the ring recognition device.

[0035] 6. In the process of determining whether the tower clearance has reached the set safety threshold, it is not necessary to identify the blade tip in the image or the tower position at the same height as the blade tip, nor is it necessary to calculate the accurate value of the tower clearance based on the image, which saves a lot of work and can ensure timely and accurate detection of whether the tower clearance has reached the set safety threshold.

[0036] 7. In determining whether the tower clearance has reached the set safety threshold, an interruption or obstruction at a certain location in the ring recognition device image will only be considered a problem if the tower clearance has reached the safety threshold if a specific time interval is required. This determination method can eliminate misjudgments caused by workers obstructing the ring recognition device when they cross it to enter or exit the wind turbine. Attached Figure Description

[0037] Figure 1 This is an overall schematic diagram of the wind turbine tower clearance monitoring system in this invention;

[0038] Figure 2 A schematic diagram showing the outer diameter setting of the ring recognition device;

[0039] Figure 3 This is a schematic diagram of the overall structure of the ring recognition device;

[0040] Figure 4 This is a schematic diagram of the segments of the ring-shaped identification device;

[0041] Figure 5 for Figure 4 A magnified view of a portion of the image;

[0042] Figure 6 This is a schematic diagram of the overall structure of the arc-shaped recognition plate;

[0043] Figure 7 This is a schematic diagram of the lower shell segment;

[0044] Figure 8This is a schematic diagram of the end face structure of the lower shell segment;

[0045] Figure 9 This is a schematic diagram of the upper shell segment;

[0046] Figure 10 This is a schematic diagram of the end face structure of the upper shell segment;

[0047] Figure 11 This is a schematic diagram of the overall structure of the support base;

[0048] Figure 12 This is a structural schematic diagram of the pad segment;

[0049] In the diagram: 1-Camera device, 2-Ring identification device, 3-Ring light strip, 4-Arc-shaped identification plate, 5-Tower, 6-Nacelle, 7-Blade, 8-Pad plate, 9-Upper shell, 10-Lower shell, 11-Drain outlet, 12-Fixing plate, 13-Overlap, 14-Ring semi-circular protrusion, 15-Ring groove, 16-Opening, 17-Support seat, 18-Upper support plate, 19-Lower support plate, 20-Support rib, 21-Inner ring, 22-Outer ring. Detailed Implementation

[0050] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. However, the scope of protection of the present invention is not limited to the following embodiments.

[0051] The overall layout diagram of the wind turbine tower clearance monitoring system provided in this embodiment is shown below. Figure 1 As shown, it includes a camera device 1 mounted on the outer shell of the nacelle 6. The camera device is mounted at the bottom of the nacelle outer shell and located between the tower 5 and the blade 7, with the lens facing downwards. The structure of the ring recognition device 2 is as follows. Figure 3 , Figure 4 and Figure 5 As shown, the ring-shaped identification device is composed of four identical arc-shaped identification plates, each segment being a quarter-circle. The ring-shaped identification device is fixed to the ground with the tower as its center, and a ring-shaped light strip is installed on it. The ring-shaped identification device, composed of four identical arc-shaped identification plates, facilitates disassembly, transportation, and installation, and also allows workers to easily transport materials and tools inside and outside the wind turbine.

[0052] The outer diameter D of the ring recognition device is 2R. Specifically, based on the tower tilt angle and blade tip distance from the tower when the tower clearance is at its minimum, a straight line is drawn from the camera device and tangent to the outer surface of the blade tip facing the tower. This line is extended to intersect the plane containing the upper surface of the ring recognition device, obtaining intersection point A. The plane containing the upper surface of the ring recognition device intersects the centerline of the tower, obtaining intersection point B. The distance between intersection point A and intersection point B is the radius R of the ring recognition device. Figure 2 As shown.

[0053] The structure of the arc-shaped recognition plate is as follows Figure 6 As shown, the device is divided into an inner ring 21 and an outer ring 22. The annular light strip is installed in the inner ring, while the outer ring is coated with identification paint. A PTC heater is installed on the lower surface of the outer ring of the arc-shaped identification plate, and the PTC heater is connected to the control device. A pad 8 is provided at the bottom of the annular light strip. The annular light strip and the pad are together wrapped and fixed inside the protective shell. Both the protective shell and the pad are made of four identical arc-shaped segments spliced ​​end to end. The protective shell consists of an upper shell 9 made of light-transmitting material and a lower shell 10 fixed to the arc-shaped identification plate. The upper shell and the lower shell are connected and fixed by buckles. The buckles are annular semi-circular protrusions 14 and annular grooves 15, which are embedded and connected by a reverse buckle. The annular semi-circular protrusions are located at the inner and outer edges of the bottom surface of the upper shell, and the annular grooves are located at the inner and outer edges of the top surface of the lower shell. The embedded fit of the annular semi-circular protrusions and annular grooves allows for quick installation of the lower and upper shells of the annular light strip protective shell without the need for bolts.

[0054] The structure of the upper shell is as follows: Figure 9 and Figure 10 As shown, it contains a heating resistance wire, which is connected to the control device. If the local rainfall is high, adjacent upper shells can be bolted together to improve the waterproof performance of the protective shell; if the local rainfall is low, adjacent upper shells do not need to be connected. The structure of the lower shell is as follows. Figure 7 and Figure 8 As shown, it has drainage outlets 11 and fixing plates 12 for fixing the lower housing. The fixing plates are connected and fixed to the arc-shaped identification plate by bolts. The drainage holes inside the lower housing can prevent water from accumulating in the lower housing of the ring-shaped light strip protective shell. Both ends of the single lower housing section are provided with overlapping joints 13 for connecting with the adjacent lower housing sections. The pad is laid on the upper surface of the internal cavity of the lower housing. The pad has two rows of openings 16 for weight reduction and heat dissipation, such as... Figure 12 As shown; the ring-shaped light strip is laid on top of the pad, and the waterproof rating of the ring-shaped light strip is not lower than IP67, and the working voltage is not higher than 36V.

[0055] The ring recognition device is fixed to the ground by a support base 17, the structure of which is as follows: Figure 11 As shown, it consists of an upper support plate 18, a lower support plate 19, and a support rib 20. The upper support plate is connected to the annular identification plate by bolts, the lower support plate is located on the ground, and the support rib is vertically connected between the upper support plate and the lower support plate.

[0056] The control device in this embodiment is not shown in the figure. It is installed on the ground and connected via a signal line ring recognition device. The control device includes a light sensor, a data acquisition and transmission module, and a PLC control module. The light sensor monitors the ambient light intensity and transmits the monitored data signal to the data acquisition and transmission module. The data acquisition and transmission module transmits the light intensity data signal to the PLC control module and then transmits it to the central processing unit via wired or wireless means. The PLC control module controls the opening and closing of the ring light strip based on the light intensity data. The control device also includes a temperature sensor that monitors the ambient temperature. The temperature sensor transmits the monitored temperature signal to the data acquisition and transmission module, which in turn transmits the temperature signal to the PLC control module. The PLC control module controls the opening and closing of the PTC heater and heating resistance wire based on the temperature signal.

[0057] In this embodiment, the central processing unit is usually a computer in the wind farm office area (not shown in the figure). The central processing unit receives light intensity data signals and image data monitored by the camera device in a wired or wireless manner, analyzes the image data and light intensity data signals, and determines whether the clearance value has reached the safety threshold.

[0058] In this embodiment, a small solar power supply (not shown in the figure) is used to provide DC power of no more than 36V to components such as the ring light strip, heating resistance wire, PTC heater, and control device.

[0059] Based on the aforementioned wind turbine tower clearance monitoring system, the method for monitoring the clearance of wind turbine towers in this embodiment includes the following steps:

[0060] S1. Determine the outer diameter of the ring recognition device. The requirements for setting the outer diameter of the ring recognition device are as follows: Based on the tower tilt angle and the distance from the blade tip to the tower when the tower clearance is at its minimum, draw a straight line from the camera device that is tangent to the outer surface of the blade tip facing the tower. Extend this line to intersect the plane containing the upper surface of the ring recognition device, obtaining intersection point A. The plane containing the upper surface of the ring recognition device intersects the center line of the tower, obtaining intersection point B. The distance between intersection point A and intersection point B is the radius R of the ring recognition device. The outer diameter D of the ring recognition device is 2R. (Refer to...) Figure 2 As shown;

[0061] S2. Install the ring recognition device at the bottom of the tower, with the center of the ring recognition device coinciding with the central axis of the tower; simultaneously install the camera device and the control device.

[0062] S3. The light sensor monitors the ambient light intensity in real time and transmits the monitoring data to the control device; the temperature sensor monitors the ambient temperature in real time and transmits the monitored temperature signal to the control device.

[0063] S4. The control device determines whether to turn the ring light strip on or off based on the magnitude of the light intensity data signal. When the light intensity is greater than the light intensity threshold, the ring light strip is turned off. When the light intensity is less than or equal to the light intensity threshold, the ring light strip is turned on to ensure high visibility even in low-light environments. When the ambient temperature is lower than the temperature threshold, the control device activates the heating function of the heating resistance wire inside the protective shell and the heating function of the PTC heater on the lower surface of the outer ring of the ring recognition plate to prevent the protective shell of the ring light strip and the outer ring of the ring recognition plate from being covered by ice and snow, thus ensuring the visibility of the ring recognition device.

[0064] In this embodiment, a ring light strip is provided in the ring recognition device. The ring light strip can be turned on or off according to the intensity of ambient light. When the ambient light is good, turning off the ring light strip can save energy; when the ambient light is poor at night or on rainy days, turning on the ring light strip can ensure the recognition accuracy of the ring recognition device.

[0065] S5. The camera device captures images of the tower in front of the impeller side in real time and transmits the image data to the central processing unit via wired or wireless means.

[0066] S6. The central processing unit stores, analyzes, and judges the received images. The analysis and judgment methods are as follows:

[0067] S6.1 The central processing unit analyzes the image. If the light intensity data signal received by the central processing unit is greater than the light intensity threshold, the ring recognition device in the image is identified based on the color characteristics and circular features of the ring recognition plate. If the light intensity data signal received by the central processing unit is less than or equal to the light intensity threshold, the ring recognition device in the image is identified based on the brightness characteristics and circular features of the ring light strip. In this embodiment, it is not necessary to identify the blade tip and the tower position at the same height as the blade tip in the image as in the prior art. It is not necessary to calculate the accurate value of the tower clearance based on the image, which saves a lot of work and can ensure timely and accurate detection of whether the tower clearance has reached the set safety threshold.

[0068] S6.2 The central processing unit (CPU) continuously compares and analyzes frame by frame of images in real time. If it finds that a certain position in the image of the ring recognition device in front of the tower on one side of the impeller is interrupted or obstructed two or more times, and the time interval between two adjacent obstructions is an integer multiple of 20 / N seconds, it indicates that the tower clearance has reached the safety threshold, and a warning signal is issued. Here, N is the impeller rotation speed N r / min obtained by the CPU from the main control system. Therefore, the speed at which the three blades successively pass the tower position is 3N r / min, and the time interval between two adjacent blades successively passing the tower position is (60 / 3N) seconds, or (20 / N) seconds. This time interval (20 / N) seconds should account for errors caused by impeller speed deviation; it is recommended to select an error within ±20%.

[0069] In this embodiment, during the process of determining whether the tower clearance has reached the set safety threshold, an interruption or obstruction at a certain location in the image of the ring recognition device is only considered a case of the tower clearance reaching the safety threshold if a specific time interval is required. This determination method eliminates misjudgments caused by workers obstructing the ring recognition device when they cross it to enter or exit the wind turbine.

Claims

1. A wind turbine tower clearance monitoring system based on ring identification device, comprising at least a camera device mounted on the nacelle housing, characterized in that: The wind turbine tower clearance monitoring system comprises: A camera is installed at the bottom of the nacelle shell and located between the tower and the blade, with the lens facing downward; An annular identification device is fixed to the ground with the tower as the center, and is composed of two or more arc-shaped identification plates spliced end to end, and is provided with an annular light belt thereon, the outer diameter D of the annular identification device is equal to 2R, specifically: according to the corresponding tower cylinder inclination angle and the blade tip to tower distance value when the tower clearance is the smallest, in this state, a straight line is drawn from the camera and tangent to the outer surface of the tower on the side facing the tower, and the straight line is extended to intersect with the plane on which the upper surface of the annular identification device is located, to obtain intersection point A, the plane on which the upper surface of the annular identification device is located intersects with the center line of the tower cylinder to obtain intersection point B, and the distance between intersection point A and intersection point B is the radius R of the annular identification device; A control device is installed on the ground and connected with the annular identification device through a signal line, the control device is provided with a light sensor, a data acquisition and transmission module and a PLC control module, the light sensor monitors the ambient light intensity and transmits the monitored data signal to the data acquisition and transmission module, the data acquisition and transmission module transmits the light intensity data signal to the PLC control module, and the light intensity data signal is transmitted to the central processor in a wired or wireless manner; the PLC control module controls the opening and closing of the annular light belt according to the light intensity data; A central processor receives the light intensity data signal and the image data monitored by the camera in a wired or wireless manner, analyzes based on the image data and the light intensity data signal, and judges whether the clearance value reaches the safety threshold; A power supply supplies power to the annular light belt in the annular identification device and the control device.

2. The ring-based identification device wind turbine tower clearance monitoring system of claim 1, wherein: The arc-shaped identification plate is divided into an inner ring and an outer ring, the annular light belt is installed at the inner ring position, and the outer ring position is brushed with identification paint; the bottom of the annular light belt is provided with a pad, and the annular light belt and the pad are jointly wrapped and fixed in a protective shell, and the protective shell and the pad are both composed of two or more arc-shaped segments spliced end to end; the protective shell is composed of an upper shell body made of light-transmitting material and a lower shell body fixed on the arc-shaped identification plate, and the upper shell body and the lower shell body are fixed by buckle connection.

3. The ring-based identification device wind turbine tower clearance monitoring system of claim 2, wherein: The upper shell body is provided with a heating resistance wire, and the outer surface of the outer ring position of the arc-shaped identification plate is provided with a PTC heater, and the heating resistance wire and the PTC heater are connected with the control device; the control device is provided with a temperature sensor that can monitor the ambient temperature, the temperature sensor transmits the monitored temperature signal to the data acquisition and transmission module, the data acquisition and transmission module transmits the temperature signal to the PLC control module, and the PLC control module controls the opening and closing of the PTC heater and the heating resistance wire according to the temperature signal.

4. The ring-based identification device wind turbine tower clearance monitoring system of claim 2, wherein: The lower shell body is distributed with a drain port and a fixing plate for fixing the lower shell body, and the fixing plate is connected and fixed with the arc-shaped identification plate by bolts; the two ends of a single lower shell body are provided with lap joints for connecting with adjacent segment lower shell bodies.

5. The ring-based identification device wind turbine tower clearance monitoring system of claim 2, wherein: The buckle is a ring-shaped semicircular protrusion and a ring-shaped groove connected in a reverse buckle manner, wherein the ring-shaped semicircular protrusion is located at the edge of the inner side and the outer side of the bottom surface of the upper shell, and the ring-shaped groove is located at the edge of the inner side and the outer side of the top surface of the lower shell.

6. The ring-based identification device wind turbine tower clearance monitoring system of claim 2, wherein: The pad is laid on the upper surface of the inner chamber of the lower shell, and two rows of openings for reducing weight and dissipating heat are arranged on the pad; the ring-shaped light strip is laid above the pad, and the waterproof grade of the ring-shaped light strip is not less than IP67, and the working voltage is not higher than 36V.

7. The ring-based identification device wind turbine tower clearance monitoring system of claim 2, wherein: The ring-shaped identification device is composed of four identical arc-shaped identification plates connected end to end, and the protective shell and the pad are also composed of four identical arc-shaped segments connected end to end.

8. The ring-based identification device wind turbine tower clearance monitoring system of claim 1, wherein: The ring-shaped identification device is fixed to the ground through the supporting seat, which is composed of an upper supporting plate, a lower supporting plate and a supporting vertical rib. The upper supporting plate is connected with the arc-shaped identification plate through bolts, and the lower supporting plate is located on the ground. The supporting vertical rib is vertically connected between the upper supporting plate and the lower supporting plate.

9. A wind turbine tower clearance monitoring method based on the wind turbine tower clearance monitoring system according to any one of claims 1-8, characterized in that The method comprises the following steps: S1, determining the outer diameter of the ring-shaped identification device, which requires the following settings: according to the corresponding tower inclination angle and the distance between the blade tip and the tower in the state of the minimum tower clearance, a straight line is drawn from the camera device and tangent to the outer surface of the side of the tower facing the tower, and the straight line is extended to intersect the plane of the upper surface of the ring-shaped identification device to obtain intersection point A. The plane of the upper surface of the ring-shaped identification device intersects the center line of the tower cylinder to obtain intersection point B. The distance between intersection point A and intersection point B is the radius R of the ring-shaped identification device, and the outer diameter D of the ring-shaped identification device is 2R; S2, installing the ring-shaped identification device at the bottom of the tower, with the center of the ring-shaped identification device coinciding with the central axis of the tower; Synchronously installing the camera device and the control device; S3, the light sensor monitors the ambient light intensity in real time and transmits the monitoring data to the control device; S4, the control device determines whether to turn on or off the ring-shaped light strip according to the size of the light intensity data signal; when the light intensity is greater than the light intensity threshold, the ring-shaped light strip is turned off; When the light intensity is less than or equal to the light intensity threshold, the ring-shaped light strip is turned on to ensure that a high distinguishability can be provided in a relatively dark environment; S5, the camera device captures the image in front of the tower near the side of the impeller in real time and transmits the image data to the central processor through wired or wireless transmission; S6, the central processor stores and analyzes the received image, and the analysis method is as follows: S6.1, the central processor analyzes the image, and if the light intensity data signal received by the central processor is greater than the light intensity threshold, the ring-shaped identification device in the image is identified according to the color feature and the circular ring feature of the arc-shaped identification plate; if the light intensity data signal received by the central processor is less than or equal to the light intensity threshold, the ring-shaped identification device in the image is identified according to the light feature and the circular ring feature of the ring-shaped light strip. S6.2, the central processor compares and analyzes the images in real time and continuously, if it is found that the image of the annular identification device in front of the tower on one side of the impeller appears 2 times or more interruptions or is blocked at a certain position, and the time interval between the adjacent two times of blocking is an integer multiple of 20 / N seconds, it is indicated that the tower clearance reaches the safety threshold, and a warning signal is sent; the N is the rotation speed of the impeller obtained from the main control system.

10. The wind turbine tower clearance monitoring method of claim 9, wherein: In step S4, when the ambient temperature is lower than the temperature threshold, the control device starts the heating function of the heating resistance wire inside the protective shell and the heating function of the PTC heater on the lower surface of the outer circle of the arc-shaped identification plate, so as to avoid the annular lamp belt protective shell and the outer circle of the arc-shaped identification plate being covered by ice and snow, and to ensure the distinguishability of the annular identification device.

Images