Fan blade clearance distance monitoring system capable of measuring rotating speed and speed measuring method thereof

Abstract

The invention relates to the technical field of wind driven generator blade clearance protection, in particular to a fan blade clearance distance monitoring system capable of measuring the rotating speed and a speed measuring method of the fan blade clearance distance monitoring system. The millimeter-wave radar technology and the millimeter-wave annular self-adaptive radar technology are adopted, so that the system is applicable all weather, is not influenced by weather and environment, can stably work in various complex environments, meets all-weather monitoring requirements, provides a stable monitoring result under various weather conditions, and has a radar measurement data updating rate as high as 500Hz. According to the invention, the change of the blade position can be quickly captured, the clearance distance of the fan blade can be monitored in real time, the distance information between the blade and the tower drum can be obtained in time, and the collision accident of the blade and the tower drum can be effectively prevented.

Description

Technical Field

[0001] The invention relates to the technical field of wind turbine blade clearance protection, and in particular to a wind turbine blade clearance distance monitoring system capable of measuring rotation speed and a distance measurement method thereof. Background Art

[0002] In recent years, major quality incidents such as blade falling, blade tearing, blade breaking, pitch bearing cracking, and wind turbine tower collapse have occurred frequently in the field of wind power. The main reason is that the power of wind turbine main engine is getting bigger and bigger, and the length of wind turbine blades is getting longer and longer. With the continuous increase of blade length, the flexibility of blades is also getting bigger and bigger. Under the condition of higher wind speed and flexible swing of tower, the radial swing of blade tip becomes larger. In extreme cases, the blade tip will sweep the tower wall, resulting in serious accidents such as tower collapse, which seriously threatens the safe operation of wind turbines. The occurrence of such preventable accidents will not only bring huge economic losses to users, but also often cause casualties. It can be seen that real-time monitoring of blade clearance distance is of great significance to ensure the safe operation of wind turbines.

[0003] At present, major wind turbine manufacturers and operators are actively researching real-time monitoring methods. There are two main monitoring products that have been tried: video images and three-line laser radar. The installation method is: install it under the body and move with it, and observe from top to bottom. Its advantages are: the monitoring position relative to the blade and the tower is fixed, the installation is simple, and it is easy to implement. The disadvantages are: the observation distance is long, the cost is high, it is easily affected by weather and environment, and it cannot achieve all-weather real-time monitoring.

[0004] Recently, some units have been studying the use of millimeter-wave radars to monitor the clearance in real time. There are two methods: one is to place the radar under the fuselage to replace the laser radar. It requires a long-range narrow-beam radar with a measurement distance greater than 100 meters. It is simple to install and easy to implement, but the cost is high. The other is to place 8 millimeter-wave radars around the tower base as described in patent application number 202311501894.8 and application number 202310429204.6. Since it monitors from bottom to top, the dust accumulation and freezing rain problems of the radar aperture transparent plate are difficult to solve, resulting in low accuracy of the measurement results, poor credibility or invalidity, and the running direction and spatial coordinates of the wind turbine head need to be referenced, and the calculation method is complicated. Summary of the invention

[0005] In view of this, the present invention proposes a fan blade clearance distance monitoring system and a distance measurement method that can measure the rotation speed. The system can monitor the fan blade clearance distance based on the millimeter-wave annular adaptive radar and measure the rotation speed, thereby improving the monitoring accuracy and reliability while ensuring the safe operation of the fan.

[0006] To achieve the above object, the technical solution of the present invention is:

[0007] A fan blade clearance distance monitoring system capable of measuring rotation speed includes a main control computer, an array unit controller, an R / T antenna and a wave-transmitting body;

[0008] Two R / T antennas are installed in each of the wave-transmitting bodies, and the R / T antennas are installed around the tower through the wave-transmitting body; wherein each R / T antenna is provided with a corresponding sequence number, and each radar array unit includes R / T antennas and an array unit controller, X is the total number of R / T antennas, and each radar array unit includes A wave-transmitting body;

[0009] The radar array unit installation height h is calculated according to the following formula:

[0010] h = H – L + Rtan(θ / 2), where the tower height is H, the blade length is L, the R / T antenna pitch angle is θ, and the distance from the radar to the blade is R;

[0011] The six array unit controllers are controlled by a main control computer and are responsible for completing the clearance measurement of the blade tip in six different areas; the main control computer is responsible for completing the calculation of the measurement data and outputting the measurement data to the main control computer in real time.

[0012] Among them, when the blade tip passes through a certain radar array unit, multiple radar R / T antennas will measure the horizontal distance of the blade tip at the same time, and the smallest measured distance among all measured distances will be selected as the clearance distance; when the blade tip passes through two adjacent radar arrays, multiple radar antennas will measure the horizontal distance of the blade tip in both arrays at the same time, and the smallest measured distance among all measured distances of the two arrays will be selected as the clearance distance; while measuring the clearance distance, the blade rotation speed is calculated, and the rotation speed and clearance distance data are output to the main control computer together.

[0013] Among them, the direction of the blades when the fan is running is automatically searched and located through electric scanning.

[0014] Among them, a buckle is installed on the back of each wave-transmitting body, and the wave-transmitting body is installed around the tower through the buckle, steel belt and cushion block; specifically, the cushion block is a magnetic cushion block, which is evenly placed horizontally at the installation height h of the radar array unit and is attracted to the outer wall of the tower; the cushion block is provided with a groove for fixing the steel belt, and the steel belt is inserted into the cushion block through the groove and connected after being around the tower for a circle; the wave-transmitting body equipped with the R / T antenna is clamped into the steel belt in the order of number through the buckle, and the connection between the two wave-transmitting bodies is tightened by an axle pin, and the electrical connectors therein are plugged in.

[0015] Among them, only the distance between the blade tip and the outer wall of the tower is measured.

[0016] The present invention also provides a speed measurement method, which uses the system of the present invention to achieve monitoring, including the following steps:

[0017] The time from the nth clearance data to the n+3th clearance data is Δt1 seconds, so the speed of the blade is n1 = 60 / Δt1 rpm;

[0018] The time from the n+1th clearance data to the n+4th clearance data is Δt2 seconds, so the speed of the second blade is n2 = 60 / Δt2 rpm;

[0019] The time from the n+2 clearance data to the n+5 clearance data is Δt3 seconds, and the rotation speed of the third blade is ω3=60 / Δt3 revolutions / second; wherein n is an arbitrary integer.

[0020] Beneficial Effects

[0021] 1. The system of the present invention adopts millimeter wave radar technology and millimeter wave circular adaptive radar technology. It is applicable all-weather and is not affected by weather and environment. It can work stably in various complex environments to meet the needs of all-weather monitoring. At the same time, it provides stable monitoring results under various weather conditions. The radar measurement data update rate is as high as 500Hz. The present invention can quickly capture the changes in the position of the blades, realize real-time monitoring of the clearance distance of the wind turbine blades, obtain the distance information between the blades and the tower in time, and effectively prevent the occurrence of collision accidents between the blades and the tower.

[0022] 2. The system of the present invention can autonomously search, locate and measure the orientation of blades, and can meet the needs of wind turbines of different models; the system reduces costs while ensuring monitoring accuracy, and implements electronic scanning in the order of the physical numbers of the R / T antennas by applying the design principle of circular adaptation through X radar R / T antennas, searches for blades when passing by, locates the orientation of the blades after scanning the blades, and then judges and determines to use the array unit or another array unit adjacent to it for measurement.

[0023] 3. The radar in the system of the present invention only performs high-speed measurement of the distance between the blade tip and the outer wall of the tower, and the radar measurement data update rate is 500Hz; the measurement data output rate is optional at 10 to 50Hz, which can accurately measure the blade clearance distance and improve the accuracy of the monitoring data.

[0024] 4. The system of the present invention is easy to install, and the radar array unit is installed in a simple and easy manner, which reduces the installation and maintenance costs. The design of the steel belt and the wave-transparent body effectively protects the radar antenna from the influence of dust and freezing rain, ensuring the stable operation of the monitoring system.

[0025] 5. The present invention can calculate the rotation speed of the blades, provide important data for the operation status analysis of the wind turbine, further ensure the safety of the wind turbine, and is applicable to wind turbines of different models and sizes, with good versatility and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The figure is a schematic diagram of the overall implementation of the fan blade clearance monitoring system based on the millimeter-wave annular adaptive radar of the present invention.

[0027] Figure 2 This is a schematic diagram of the installation layout of the annular adaptive radar array of the system of the present invention on the outer wall of the tower.

[0028] Figure 3 Schematic diagram of the annular adaptive radar array unit of the system of the present invention.

[0029] Figure 4 This is a schematic diagram of the installation of internal and external components of the annular adaptive radar array wave-transmitting body of an embodiment of the system of the present invention.

[0030] Figure 5 This is a schematic diagram of the installation details of the annular adaptive radar on the outer wall of the tower according to the system embodiment of the present invention. DETAILED DESCRIPTION

[0031] The present invention is described in detail below with reference to the accompanying drawings and embodiments.

[0032] The present invention proposes a fan blade clearance distance monitoring system capable of measuring rotation speed, comprising a ring-shaped adaptive radar main control computer, an array unit controller, a ring-shaped adaptive radar R / T antenna and a wave-transmitting body; the fan blade clearance monitoring system based on the millimeter-wave ring-shaped adaptive radar is generally implemented as follows: Figure 1 As shown, the blade length is L, the tower height is H, the radar installation height is h, the R / T antenna pitch angle is θ, the R / T antenna azimuth angle is σ, the distance from the radar to the blade is R, and the distance from the R / T antenna surface of the wave-transmitting body to the tower wall is d.

[0033] In the system of the present invention, two R / T antennas are installed in each wave-transmitting body, and the R / T antennas are installed around the tower through the wave-transmitting body; wherein each R / T antenna is provided with a corresponding sequence number, and all R / T antennas form 6 radar array units, and the annular adaptive radar array is installed on the outer wall of the tower in the following layout: Figure 2 As shown, Figure 1 and Figure 2 The six radar array units shown are A1-A6, each radar array unit includes R / T antennas and an array unit controller, X is the total number of R / T antennas, and each radar array unit includes ( The installation height h of the radar array unit is calculated according to the following formula: h = H – L + Rtan (θ / 2).

[0034] The annular adaptive radar array unit of the system of the present invention is as follows Figure 3 As shown. Figure 3 (a) is the front view of the array unit. Figure 3 (b) is a top view of the array unit; the six array unit controllers are controlled by the main control computer and are responsible for completing the clearance measurement when the blade tip is in six different areas; the main control computer is responsible for completing the calculation of the measurement data and outputting the measurement data to the main control computer in real time; when the blade tip passes over a certain radar array unit, multiple radar R / T antennas will measure the horizontal distance of the blade tip at the same time, and the smallest measurement distance among all measurement distances will be selected as the clearance distance; when the blade tip passes over two adjacent radar arrays, multiple radar antennas will measure the horizontal distance of the blade tip at the same time in both arrays, and the smallest measurement distance among all measurement distances of the two arrays will be selected as the clearance distance; while measuring the clearance distance, the rotation speed of the blade is calculated, and the rotation speed and the clearance distance data are output to the main control computer together. The clearance distance measurement of the present invention is independent of the tower diameter. The system of the present invention automatically searches and locates the direction of the blades when the fan is running by electronic scanning, without the need for an external system to provide fan direction data.

[0035] Furthermore, in the embodiment of the present invention, a buckle is installed on the back of each wave-transparent body, and the wave-transparent body is installed around the tower by means of the buckle, steel belt and pad; specifically, the pad is a magnetic pad, which is evenly placed horizontally at the installation height h of the radar array unit and firmly attracted to the outer wall of the tower; the pad is provided with a groove for fixing the steel belt, and the steel belt is inserted into the pad through the groove and fastened around the tower; the wave-transparent body equipped with the R / T antenna is clipped into the steel belt in numerical order by the buckle, and the two wave-transparent bodies are fastened by an axle pin, and the electrical connectors therein are plugged in. The internal and external components of the annular adaptive radar array wave-transparent body of the system embodiment of the present invention are installed as follows: Figure 4 As shown, the installation details of the annular adaptive radar on the outer wall of the tower are as follows Figure 5 shown.

[0036] In summary, the system of the present invention applies the design principle of circular adaptation through X radar R / T antennas, implements electronic scanning according to the physical numbering order of the R / T antennas, searches for the blades when passing by, locates the direction of the blades after scanning the blades, and then judges and determines to use the array unit or another array unit adjacent to it for measurement. Specifically, when a radar array unit performs clearance measurement, the main control computer can control other array units to enter a dormant state through the array controller. When the wind direction causes the wind turbine to rotate in a certain direction along the tower, if it reaches the R / T antenna on the edge of the array unit that is working, the main control computer will promptly wake up the array unit adjacent to it to join the clearance measurement; in the conical area scanned by the radar R / T antenna of the present invention, multiple antennas will measure the distance between the blade and the R / T antenna at the same time, and according to the R / T antenna layout, the minimum measurement distance is selected as the blade clearance distance. The radar of the present invention only measures the distance between the blade tip and the outer wall of the tower at a high speed, and the radar measurement data update rate is 500Hz; the measurement data output rate is optional at 10 to 50Hz.

[0037] The present invention also provides a speed measurement method of a fan blade clearance distance monitoring system capable of measuring rotation speed, and the monitoring is realized by using the system of the present invention, comprising the following steps:

[0038] The time from the nth clearance data to the n+3th clearance data is Δt1 seconds, so the speed of the blade is n1 = 60 / Δt1 rpm;

[0039] The time from the n+1th clearance data to the n+4th clearance data is Δt2 seconds, so the speed of the second blade is n2 = 60 / Δt2 rpm;

[0040] The time from the n+2 clearance data to the n+5 clearance data is Δt3 seconds, and the rotation speed of the third blade is ω3=60 / Δt3 revolutions / second, where n is an arbitrary integer.

[0041] In summary, the above are only preferred embodiments of the present invention and are not intended to limit the protection scope of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A fan blade clearance distance monitoring system capable of measuring rotation speed, characterized in that: A fan blade clearance distance monitoring system capable of measuring rotation speed includes a main control computer, an array unit controller, an R / T antenna and a wave-transmitting body; Two R / T antennas are installed in each of the wave-transmitting bodies, and the R / T antennas are installed around the tower through the wave-transmitting bodies; wherein each R / T antenna is provided with a corresponding sequence number, each radar array unit includes X / 6 R / T antennas and an array unit controller, X is the total number of R / T antennas, and each radar array unit includes X / 12 wave-transmitting bodies; The radar array unit installation height h is calculated according to the following formula: h=H–L+Rtan(θ / 2), where the tower height is, the blade length is, the R / T antenna pitch angle is, and the distance from the radar to the blade is; The six array unit controllers are controlled by a main control computer and are responsible for completing the clearance measurement of the blade tip in six different areas; the main control computer is responsible for completing the calculation of the measurement data and outputting the measurement data to the main control computer in real time.

2. The system according to claim 1, characterized in that When the blade tip passes over a radar array unit, multiple radar R / T antennas will measure the horizontal distance of the blade tip at the same time, and the smallest measured distance among all measured distances will be selected as the clearance distance; when the blade tip passes over two adjacent radar arrays, multiple radar antennas will measure the horizontal distance of the blade tip in both arrays at the same time, and the smallest measured distance among all measured distances of the two arrays will be selected as the clearance distance; while measuring the clearance distance, the blade rotation speed is calculated, and the rotation speed and clearance distance data are output to the main control computer together.

3. The system according to claim 1, characterized in that Automatically search and locate the direction of the blades when the fan is running through electronic scanning.

4. The system according to any one of claims 1 to 3, characterized in that: A buckle is installed at the back of each wave-transmitting body, and the wave-transmitting body is installed around the tower through the buckle, steel belt and pad; specifically, the pad is a magnetic pad, which is evenly placed horizontally at the installation height h of the radar array unit and is attracted to the outer wall of the tower; the pad is provided with a groove for fixing the steel belt, and the steel belt is inserted into the pad through the groove and connected after being around the tower; the wave-transmitting body equipped with the R / T antenna is clamped into the steel belt in the order of number through the buckle, and the two wave-transmitting bodies are connected and fastened with an axle pin, and the electrical connectors therein are plugged in.

5. The system according to claim 4, characterized in that Only the distance between the blade tip and the tower outer wall is measured.

6. A speed measurement method, characterized in that: The monitoring is realized by using the fan blade clearance distance monitoring system capable of measuring the rotation speed as claimed in any one of claims 1 to 5, comprising the following steps: The time from the nth clearance data to the n+3th clearance data is Δt1 seconds, so the speed of the blade is n1 = 60 / Δt1 rpm; The time from the n+1th clearance data to the n+4th clearance data is Δt2 seconds, so the speed of the second blade is n2 = 60 / Δt2 rpm; The time from the n+2 clearance data to the n+5 clearance data is Δt3 seconds, and the rotation speed of the third blade is ω3=60 / Δt3 revolutions / second; wherein n is an arbitrary integer.

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