A fan blade moving blade opening online measurement method and device

Abstract

The application discloses a kind of fan blade moving blade opening online measurement method and device, the application object of this method is power station moving blade regulating type axial flow fan, it is related to power station fan blade opening online monitoring sensor arrangement scheme and its test method.This method is based on tip timing method, by arranging tip sensor in the corresponding shell specific position of power station fan wheel swept area, arranging key phase sensor in the specific position of fan main shaft, measuring the signal of different positions through tip sensor at the tip of fan blade, calculating the phase information of different positions of fan blade axis relative to key phase zero point, and obtaining the actual opening paddle angle information of fan blade by conversion.This information can be used for the blade opening asynchronous fault diagnosis of power station fan, solves the problem that the actual opening of moving blade regulating type axial flow fan blade is difficult to monitor.The principle of this method is simple, easy to apply, and has good application prospect.

Description

Technical Field

[0001] This invention belongs to the field of online monitoring of power plant wind turbines, specifically relating to an online measurement method and device for the opening degree of wind turbine blades. Background Technology

[0002] The adjustable-blade axial flow fan is an important type of ventilation equipment. Its key feature is that the blade angle can be changed by adjusting the rotation position of the blades, thus achieving precise control over airflow and pressure. The working principle of the adjustable-blade axial flow fan is relatively complex but highly efficient. When airflow enters the fan from the system duct, it first changes direction through the air box, then flows through the collector to converge and accelerate before flowing to the impeller. The motor provides power to the impeller, enabling it to perform work on the airflow. The blade working angle and blade pitch are steplessly adjustable, allowing for changes in airflow and pressure according to varying operating conditions. After passing through the impeller, the airflow rotates, then flows axially into the diffuser after passing through the rear guide vanes. Inside the diffuser, some of the gas's kinetic energy is converted into static pressure energy, before flowing back to the system to meet operational requirements, thus completing the fan's output process.

[0003] Due to their advantages such as small size, light weight, high efficiency in low-load areas, wide adjustment range, and fast response speed, axial flow fans with adjustable blades have significant economic advantages compared to centrifugal fans and static blade fans. Therefore, they are widely used to replace old-fashioned centrifugal fans in energy-saving technology renovation projects of coal-fired power plants in China.

[0004] The blade adjustment mechanism of a variable-blade axial flow fan is relatively complex. It typically uses a hydraulic cylinder and an actuating disc to drive a slider on a crank at the root of the blade, causing the crank to swing and the blades to rotate around an adjustment shaft, thus changing the blade opening. In actual operation, under the influence of corrosive exhaust gases, alternating vibration loads, and centrifugal loads, variable-blade axial flow fans are prone to mechanical failures such as crank deformation, and corrosion or wear of the slider or actuating disc after a period of operation. This can lead to asynchronous blade openings or deviations between the actual and controlled blade openings during adjustment, affecting fan efficiency and increasing fan vibration.

[0005] Existing axial flow fans with adjustable blades mainly rely on control system feedback values ​​such as the actuation stroke of the actuator or the pumping volume of hydraulic oil to monitor the blade opening. When the end of the actuator, such as the slider, actuator plate, or crank, malfunctions, the control system cannot accurately reflect the actual blade opening. Therefore, it is necessary to set up an online blade opening measurement system independent of the control system.

[0006] Currently, some studies use pressure sensors to attempt to indirectly measure the blade opening of a wind turbine from the flow field characteristics at the impeller outlet, and to diagnose problems such as signal opening asynchrony. This technical approach is difficult to calibrate, easily affected by other flow field factors, and cannot accurately monitor the blade opening; it can only monitor more severe blade opening asynchrony faults. Summary of the Invention

[0007] The purpose of this invention is to provide an online measurement method and device for the blade opening of a wind turbine. This invention is applied to a power plant blade-adjustable axial flow fan. It can measure the actual opening of each blade of the fan during operation, and is used to diagnose faults such as asynchronous blade adjustment and incomplete blade adjustment that occur during the operation of the blade-adjustable axial flow fan.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] This invention provides an online measurement device for the moving blade opening of a wind turbine blade, comprising a key phase sensor, an opening sensor, a shaft sensor, and a key phase measuring point;

[0010] The key phase sensor is installed in a non-contact manner at the fan coupling or motor output shaft, acquiring a key phase signal once per rotation. The opening sensor and shaft sensor are installed on the casing through openings in the casing. The arrangement of the key phase measuring points ensures that the starting point of the key phase calculation is located within the angle range formed by the leading edge of the blade and the opening adjustment rotation axis of the previous blade when the blade opening is at its minimum.

[0011] A further improvement of the present invention is that the key phase sensor and the opening degree sensor are arranged in phase.

[0012] A further improvement of this invention is that the bond phase is obtained by a photoelectric sensor in conjunction with reflective paper.

[0013] A further improvement of the present invention is that the bond phase is obtained by using an eddy current sensor in conjunction with a keyway.

[0014] A further improvement of the present invention is that the opening sensor is a blade tip sensor used to record the blade tip passing signal. The sensor type is a fiber optic sensor or an eddy current sensor, which is installed radially on the casing in the blade rotation plane. The center line of the sensor is located in front of or behind the blade opening adjustment rotation axis along the axial position of the fan shaft. If the space allows for the sensor arrangement, it should be arranged in front of the blade opening adjustment rotation axis.

[0015] A further improvement of the present invention is that the shaft sensor is a blade tip sensor used to record the blade tip passing signal. The sensor type is a fiber optic sensor or an eddy current sensor, which is installed radially on the casing in the blade rotation plane. The center line of the sensor is at the same axial position along the fan shaft as the axial position of the blade opening adjustment rotation shaft.

[0016] A further improvement of the present invention is that the key phase sensor, in conjunction with the key phase measuring point, is used to measure the rotational speed of the fan rotor and to provide key phase information during the rotor's operation.

[0017] This invention also provides an online measurement method for the moving blade opening of a wind turbine blade, which is based on the aforementioned online measurement device for the moving blade opening of a wind turbine blade, and includes:

[0018] Step 1: Count the blade tip transmission signals of the blade opening sensor and the blade tip transmission signals of the shaft sensor respectively, and determine whether the blade opening is within the monitoring range by comparing the difference in counts;

[0019] Step 2: When the blade opening is within the monitoring range, record the opening sensor phase data and shaft sensor phase data for each blade in each cycle, and record continuously for 16 full cycles.

[0020] Step 3: Calculate the average phase of the blade opening sensor and the average phase of the shaft sensor within 16 whole cycles, and calculate the difference for each blade separately;

[0021] Step 4: Compare and interpolate the phase difference of the blades with the phase difference and blade opening calibration data under normal operating conditions to obtain the actual opening of each blade.

[0022] A further improvement of this invention lies in the method for obtaining the phase difference and blade opening calibration data under normal operating conditions:

[0023] After installing the sensors and key phase measurement points as required, with the wind turbine blade adjustment mechanism functioning normally, adjust the wind turbine blades to different opening degrees and run at low speeds. Measure the phase difference between the opening degree sensor and the shaft sensor under different blade opening conditions to establish the correspondence between the wind turbine blade opening degree and the phase difference measured by the sensor.

[0024] A further improvement of the present invention is that the method identifies the actual opening of the wind turbine blade by measuring the phase difference between the blade tip signal monitored by the opening sensor and the blade tip signal monitored by the shaft sensor.

[0025] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0026] This invention provides an online measurement method and apparatus for wind turbine blade moving blade opening. By arranging two blade tip sensors axially along the blade's rotation area, the method directly measures the passing phase of the wind turbine blade tip and calculates the wind turbine blade angle using the phase difference. Compared to methods that diagnose blade opening based on aerodynamic data, this invention's direct measurement method offers higher fault diagnosis accuracy and can pinpoint the fault to a specific blade, exhibiting greater stability. Furthermore, this invention can locate the fault point to a specific blade when diagnosing asynchronous moving blade opening faults. Attached Figure Description

[0027] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0028] Appendix Figure 1 This is an overall schematic diagram of an embodiment of the present invention.

[0029] Appendix Figure 2 This is a schematic diagram of the blade tip sensor arrangement in an embodiment of the present invention.

[0030] Appendix Figure 3 This is a schematic diagram of the sensor arrangement phase in an embodiment of the present invention.

[0031] Appendix Figure 4 This is a graph showing the relationship between blade opening and the blade tip sensor signal.

[0032] Appendix Figure 5 This is a flowchart of the blade opening conversion algorithm of the present invention.

[0033] Explanation of reference numerals in the attached figures:

[0034] 1. Key phase sensor; 2. Opening degree sensor; 3. Rotary shaft sensor; 4. Blade opening degree adjustment rotating shaft; 5. Key phase measuring point; 6. Key phase calculation starting point; 7. Key phase calculation starting point layout range. Detailed Implementation

[0035] In the following description, only certain exemplary embodiments are briefly described. As those skilled in the art will recognize, the described embodiments can be modified in various ways without departing from the spirit or scope of the invention. Therefore, the drawings and description are considered to be exemplary in nature and not restrictive.

[0036] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0037] In this invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0038] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0039] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0040] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0041] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0042] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0043] Example 1

[0044] like Figures 1 to 3 As shown, this embodiment provides an online measurement device for the moving blade opening of a wind turbine blade, including a key phase sensor 1, an opening sensor 2, a shaft sensor 3, and key phase measuring points 5. The key phase sensor 1 is installed in a non-contact manner at the wind turbine coupling or the motor output shaft, acquiring a key phase signal once per rotation. The opening sensor 2 and the shaft sensor 3 are installed on the casing through openings in the casing. The arrangement of the key phase measuring points 5 ensures that the key phase calculation starting point 6 is located within the angle range 7 formed by the blade leading edge and the previous blade opening adjustment rotation shaft 4 when the blade opening is at its minimum.

[0045] In this embodiment, as Figure 3 As shown, the key phase sensor 1 and the opening sensor 2 are arranged in phase. The arrangement of the key phase measuring point 5 should ensure that the key phase calculation starting point 6 is located within the angle range 7 formed by the leading edge of the blade and the previous blade opening adjustment rotation axis 4 when the blade opening is at its minimum. This prevents the blade tip signal from exceeding the phase range during blade opening adjustment, thus avoiding blade coding errors. When the key phase sensor 1 and the opening sensor 2 are arranged in phase, their temporal consistency is ensured, avoiding confusion caused by phase differences during data processing. By setting the key phase calculation starting point 6 within the angle range 7 formed by the leading edge of the blade and the previous blade opening adjustment rotation axis 4 when the blade opening is at its minimum, it is ensured that the blade tip signal remains within the expected phase range during blade opening adjustment.

[0046] In this embodiment, the bond phase can be obtained using a photoelectric sensor with reflective paper or an eddy current sensor with a keyway. When using a photoelectric sensor with reflective paper to obtain the bond phase, reflective paper is attached to the rotating component as a marker. As the component rotates, the photoelectric sensor detects the position of the reflective paper by receiving and reflecting light. Each time the sensor passes the reflective paper, a pulse signal is triggered. This method is convenient for phase measurement and improves work efficiency. The photoelectric sensor is highly adaptable to the environment and can operate in various conditions.

[0047] When using an eddy current sensor with a keyway to acquire the key phase, a keyway is machined into the rotating component as a marker. The eddy current sensor generates a pulse signal by measuring the change in distance between the probe and the surface of the rotor being measured. When the rotating component rotates to the keyway position, the distance between the probe and the measured surface changes, thus triggering the pulse signal. This method provides stable and reliable keyway marking, is not easily affected by the environment, and the eddy current sensor exhibits high measurement accuracy and sensitivity.

[0048] The key phase sensor 1, in conjunction with the key phase measuring point 5, is used to measure the rotational speed of the fan rotor and provide key phase information during rotor operation.

[0049] In this embodiment, the opening sensor 2 is a blade tip sensor used to record the blade tip passing signal. The sensor type is an eddy current sensor, which is installed radially on the casing in the blade rotation plane. The center line of the sensor is located in front of the blade opening adjustment rotation axis along the axial position of the fan shaft. The axial distance of the sensor axis is slightly greater than 3 times the diameter of the eddy current sensor to ensure that the eddy current sensor obtains the largest possible blade opening measurement range under the condition that there is no mutual interference.

[0050] One type of sensor is the blade tip sensor, used to detect the gap between the tip of an impeller or blade and surrounding structures (such as a casing or inner wall) in rotating machinery. Eddy current sensors, also known as eddy current measurement sensors, are sensors that utilize the principle of eddy currents for measurement and detection. Their working principle is based on Faraday's law of electromagnetic induction and Lenz's law. When a bulk metal conductor is placed in a changing magnetic field or moves through a magnetic field cutting magnetic lines of force, an induced current in the form of eddy currents is generated within the conductor. This current is called an eddy current, and the phenomenon is known as the eddy current effect. Eddy current sensors use the reverse magnetic field generated by these eddy currents to measure the relative position of the measured metal conductor and the probe end face.

[0051] In this embodiment, the shaft sensor 3 is a blade tip sensor used to record the blade tip passing signal. The sensor type is an eddy current sensor, radially mounted on a casing within the blade's rotation plane. The sensor's centerline is aligned with the axial position of the blade opening adjustment shaft, ensuring that the blade tip phase angle monitored by the shaft sensor is essentially consistent during blade opening adjustment. Figure 2 Appendix Figure 4 As shown, in this embodiment, the opening sensor 2 and the shaft sensor 3 are arranged with the same phase angle. The opening sensor 2 receives the blade passing signal first, and the shaft sensor 3 receives the blade passing signal later.

[0052] Example 2

[0053] like Figure 5 As shown in the figure, this embodiment provides an online measurement method for the moving blade opening of a wind turbine, including:

[0054] Step 1: Count the blade tip transmission signals of the blade opening sensor and the blade tip transmission signals of the shaft sensor respectively, and determine whether the blade opening is within the monitoring range by comparing the difference in counts;

[0055] Step 2: When the blade opening is within the monitoring range, record the opening sensor phase data and shaft sensor phase data for each blade in each cycle, and record continuously for 16 full cycles.

[0056] Step 3: Calculate the average phase of the blade opening sensor and the average phase of the shaft sensor within 16 whole cycles, and calculate the difference for each blade separately;

[0057] Step 4: Compare and interpolate the phase difference of the blades with the phase difference and blade opening calibration data under normal operating conditions to obtain the actual opening of each blade.

[0058] Example 3

[0059] like Figure 5 As shown in the figure, this embodiment provides an online measurement method for the moving blade opening of a wind turbine, including:

[0060] Step 1: Count the blade tip transmission signals of the blade opening sensor and the blade tip transmission signals of the shaft sensor respectively, and determine whether the blade opening is within the monitoring range by comparing the difference in counts;

[0061] Step 2: When the blade opening is within the monitoring range, record the opening sensor phase data and shaft sensor phase data for each blade in each cycle, and record continuously for 16 full cycles.

[0062] Step 3: Calculate the average phase of the blade opening sensor and the average phase of the shaft sensor within 16 whole cycles, and calculate the difference for each blade separately;

[0063] Step 4: Compare the phase difference of the blades with the phase difference under normal operating conditions. ΔΦ and blade opening O Calibration data Δ Φ The actual opening degree of each blade is obtained by comparison and calculation, as shown in the following formula. O r .

[0064]

[0065] In this embodiment, the phase difference and blade opening calibration data under normal operating conditions involved in step 4 of the blade opening conversion algorithm of the present invention are obtained as follows:

[0066] After installing the sensors and key phase measuring points as required, and with the wind turbine blade adjustment mechanism functioning normally, adjust the wind turbine blades to different opening degrees. O During low-speed operation, the phase difference between the blade opening sensor and the shaft sensor was measured at different blade opening degrees. ΔΦ 0. Establish the correspondence between the percentage of wind turbine blade opening and the phase difference measured by the sensor.

[0067] In this embodiment, as Figure 4As shown, the blade opening conversion algorithm identifies the actual opening of the blade by the phase difference change between the blade tip signal monitored by the opening sensor 2 and the blade tip signal monitored by the shaft sensor 3.

[0068] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the scope of the invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0069] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can be appropriately combined to form other embodiments that can be understood by those skilled in the art. The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. An online measuring device for the opening degree of a wind turbine blade, characterized in that, It includes a key phase sensor (1), an opening sensor (2), a shaft sensor (3), and a key phase measuring point (5); The key phase sensor (1) is installed in a non-contact manner at the fan coupling or motor output shaft, and acquires a key phase signal once per rotation; the opening sensor (2) and the shaft sensor (3) are installed on the casing through the casing opening; the arrangement of the key phase measuring points (5) makes the key phase calculation starting point (6) located within the angle range (7) formed by the blade leading edge and the previous blade opening adjustment rotation shaft (4) when the blade opening is at its minimum. The opening sensor (2) is a blade tip sensor used to record the blade tip passing signal. The sensor type is a fiber optic sensor or an eddy current sensor. It is installed radially on the casing in the blade rotation plane. The center line of the sensor is located in front of or behind the blade opening adjustment rotation shaft along the axial position of the fan shaft. The rotating shaft sensor (3) is a blade tip sensor used to record the blade tip passing signal. The sensor type is a fiber optic sensor or an eddy current sensor. It is installed radially on the casing in the blade rotation plane. The center line of the sensor is in the same axial position along the fan shaft as the axial position of the blade opening adjustment rotating shaft.

2. The online measuring device for the moving blade opening of a wind turbine blade according to claim 1, characterized in that, The key phase sensor (1) and the opening sensor (2) are arranged in the same phase.

3. The online measuring device for the moving blade opening of a wind turbine blade according to claim 1, characterized in that, The bond phase is obtained using a photoelectric sensor in conjunction with reflective paper.

4. The online measuring device for the moving blade opening of a wind turbine blade according to claim 1, characterized in that, The key phase is obtained using an eddy current sensor in conjunction with a keyway.

5. The online measuring device for the moving blade opening of a wind turbine blade according to claim 1, characterized in that, Where space permits, the opening sensor (2) should be placed in front of the blade opening adjustment rotation shaft.

6. The online measuring device for the moving blade opening of a wind turbine blade according to claim 1, characterized in that, The key phase sensor (1) is used in conjunction with the key phase measuring point (5) to measure the rotational speed of the fan rotor and to provide key phase information during the rotor operation.

7. A method for online measurement of the opening degree of a wind turbine blade, characterized in that, This method is based on an online measuring device for the moving blade opening of a wind turbine blade according to any one of claims 1 to 6, comprising: Step 1: Count the blade tip transmission signals of the blade opening sensor and the blade tip transmission signals of the shaft sensor respectively, and determine whether the blade opening is within the monitoring range by comparing the difference in counts; Step 2: When the blade opening is within the monitoring range, record the opening sensor phase data and shaft sensor phase data for each blade in each cycle, and record continuously for 16 full cycles. Step 3: Calculate the average phase of the blade opening sensor and the average phase of the shaft sensor within 16 whole cycles, and calculate the difference for each blade separately; Step 4: Compare and interpolate the phase difference of the blades with the phase difference and blade opening calibration data under normal operating conditions to obtain the actual opening of each blade.

8. The method for online measurement of the moving blade opening of a wind turbine blade according to claim 7, characterized in that, The method for obtaining phase difference and blade opening calibration data under normal operating conditions is as follows: After installing the sensors and key phase measurement points as required, with the wind turbine blade adjustment mechanism functioning normally, adjust the wind turbine blades to different opening degrees and run at low speeds. Measure the phase difference between the opening degree sensor and the shaft sensor under different blade opening conditions to establish the correspondence between the wind turbine blade opening degree and the phase difference measured by the sensor.

9. The method for online measurement of the moving blade opening of a wind turbine blade according to claim 7, characterized in that, This method identifies the actual opening of the wind turbine blade by measuring the phase difference between the blade tip signal monitored by the opening sensor (2) and the blade tip signal monitored by the shaft sensor (3).

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