An online detection method for wind turbine blade angle consistency

Abstract

The present invention relates to the technical field of wind power generation, and in particular to an online detection method for the angle consistency of blades of a wind turbine, the method comprising numbering the blades of the wind turbine as a first blade, a second blade and a third blade; obtaining the vibration velocity amplitude of each vibration sensor and the phase of the third velocity sensor through vibration signals collected by a first, second and third vibration velocity sensors and a key phase signal collected by a key phase sensor; judging the consistency of the blade angle by comparing the vibration velocity amplitudes of the first and second velocity sensors with a warning value; when the blade angles are inconsistent, judging the inconsistency of the angle of a specific blade by the phase of the third vibration velocity amplitude; the calculation method of the present invention is simple and can accurately detect the consistency of the blade angle, and the sensor is easy to install and low in cost, without entering the blade hub to perform complicated work, and at the same time the blade status can be detected online, reducing downtime time and cost.

Description

Technical Field

[0001] The present invention relates to the technical field of wind power generation, and in particular to an online detection method for the angle consistency of blades of a wind turbine generator set. Background Art

[0002] The main function of the blades on the wind turbine casing is to capture wind energy and convert it into mechanical energy, which is then converted into electrical energy through the generator. The blade angle should be set appropriately and the angles of the three blades should be consistent, so that the blades face the wind with maximum efficiency, thereby ensuring the power generation efficiency of the generator; inconsistent blade angles will cause the wind turbine to be unable to reach the optimal windward angle, thereby reducing power output and causing uneven rotation speed, which in turn affects the overall efficiency of the generator. If the angles of some blades are too large, the rotation speed may slow down, while blades with too small an angle may wear out more due to high resistance, affecting the stability and life of the equipment; at the same time, inconsistent blade angles may cause noise levels to rise, affecting the quality of the surrounding environment.

[0003] In the existing technology, the detection of the blade angle of the generator set mainly relies on the following technologies: laser ranging and contour curve fitting technology. After searching, it is found that a Chinese patent document discloses a method and device for detecting the blade angle of a wind turbine set [Application No.: CN202410581314.9]. It uses a laser ranging device to collect the distance data of the blade and the tower in real time, combines the algorithm to generate the blade contour curve, calculates the torsion angle and angle deviation, and is suitable for real-time monitoring under grid-connected operation. It has high accuracy and does not require shutdown operation, but its cost is high, and the stability requirements of the laser calibration device are high; Image recognition technology: using image processing technology combined with deep learning models to identify the blade orientation angle. Its advantages are non-contact detection, applicable to complex lighting and dynamic scenes, and support for remote monitoring. Its disadvantages are that it requires a lot of model training and complex background processing, and the calculation accuracy is low; Sensor triggers automatic Zeroing system: Sensors (such as displacement sensors or fiber optic sensors) are installed on the hub and blades to automatically adjust the angle through signal feedback. The advantage is fully automated operation, suitable for large units and frequent maintenance scenarios, and strong anti-interference ability. The disadvantage is that it is generally used for large units, has high cost, and requires frequent maintenance; Mechanical load detection method: The torque change is analyzed through the load sensor installed at the blade root (such as fiber grating sensor or strain gauge). The advantage is that it is suitable for complex mechanical environments, provides an absolute zero reference, and does not require visual calibration. The disadvantage is that it has high requirements for the sensor installation position, and the data changes a lot during operation, requiring strong data analysis capabilities; Mechanical and laser combined detection device: A mechanical structure is used in conjunction with a laser rangefinder to achieve high-precision detection. The advantage is strong portability, suitable for rapid on-site detection, and low cost. The disadvantage is that the mechanical structure precision control is difficult and the measurement error is large. Summary of the Invention

[0004] The object of the present invention is to provide an online detection method for the angle consistency of blades of a wind turbine generator set, which obtains the vibration velocity amplitudes of the three vibration velocity sensors and the phase of the third vibration velocity sensor through three vibration velocity sensors combined with a key phase sensor, judges the consistency of the blade angle according to the vibration velocity amplitude, and can judge the angle inconsistency of a specific blade in combination with the phase; the present invention can perform online real-time detection of the blade angle, reducing downtime time and cost; at the same time, the three vibration velocity sensors and the key phase sensor are easy to install and low in cost, do not require complex installation environment requirements, and do not need to enter the blade hub to perform complex work, reducing labor costs; the calculation method of the present invention is convenient and can accurately judge the situation of the blade angle.

[0005] To achieve the above object, the present invention provides the following technical solution: an online detection method for the angle consistency of wind turbine blades, comprising the following steps:

[0006] Step S1: numbering the three blades of the fan as the first blade, the second blade, and the third blade respectively;

[0007] Step S2: obtaining a vibration velocity amplitude and phase of the vibration velocity sensor by combining a vibration signal collected by the vibration velocity sensor with a key phase signal collected by the key phase sensor; the number of the vibration velocity sensors is set to three and numbered as a first vibration velocity sensor, a second vibration velocity sensor, and a third vibration velocity sensor; the vibration velocity sensors are all located in the vibration sensitive area of ​​the fan and arranged axially, the third vibration velocity sensor is located at the top of the vibration sensitive area, the first vibration velocity sensor and the second vibration velocity sensor are 90° to each other and are symmetrically distributed with the third vibration velocity sensor as the center; the key phase sensor is installed on the rotating component; the vibration velocity amplitudes of the first vibration velocity sensor, the second vibration velocity sensor, and the third vibration velocity sensor are marked as A, B, and C, respectively; and the phase value of the third vibration velocity sensor is marked as φ;

[0008] Step S3: The vibration velocity amplitudes A and B are calculated using a formula to obtain a warning value D. The vibration velocity amplitude C is compared with the warning value D to determine the consistency of the blade angle. The calculation formula is as follows:

[0009] D= (1)

[0010] Wherein, D is the warning value, A is the vibration velocity amplitude measured by the first vibration velocity sensor; B is the vibration velocity amplitude measured by the second vibration velocity sensor;

[0011] Step S4: If the blade angles are consistent, no adjustment is required. If the blade angles are inconsistent, the phase φ interval is used to determine whether a specific blade has an inconsistent angle. The phase φ interval is (0°, 90°) or (120°, 210°) or (240°, 330°).

[0012] Preferably, in step S1, the three blades of the fan are numbered as the first blade, the second blade and the third blade respectively, and the specific method is: select one of the blades to be numbered as the first blade and set the angle to 0°, take a key phase indicator bar as the key phase signal mark and install it on the rotating component, the axis of the key phase indicator bar, the axis of the key phase sensor, and the axis of the root of the first blade, the three axes are collinear in their positive projections on the surface parallel to the axis of the rotating component; number the remaining two blades as the second blade and the third blade in sequence according to the direction of rotation of the fan, and set the angle of the second blade to 120° and the angle of the third blade to 240° in the opposite direction of rotation of the fan.

[0013] Preferably, in step S2, the vibration velocity amplitude and phase of the vibration velocity sensor are obtained by combining the vibration signal collected by the vibration velocity sensor with the key phase signal collected by the key phase sensor, and the specific method is:

[0014] Step S2.1: The Fourier transform of the non-periodic continuous-time signal f(t) can be expressed as:

[0015] (2)

[0016] in: is a rotation factor, j is the imaginary unit, ω is the angular frequency, rad / s, t is the time, s; X( ) is the continuous spectrum of f(t); f(t) is a non-periodic continuous time signal;

[0017] Step S2.2: For the non-periodic continuous-time signal f(t), it can be converted into:

[0018] (3)

[0019] Where f(t) is a non-periodic continuous time signal, that is, a continuous function that changes with time; A is the vibration velocity amplitude; ψ is the corresponding phase value; n is the maximum sampling frequency of the instrument equipment, n ≥ 1; k is the frequency domain sequence number, corresponding to the actual frequency; t is the time variable, indicating the continuous change of the signal in the time domain;

[0020] Step S2.3: Obtain the blade rotation speed per minute through the key phase signal collected by the key phase sensor, and obtain the main vibration frequency of each vibration velocity sensor according to the rotation speed. The main frequency calculation formula is:

[0021] (4)

[0022] Where f is the main vibration frequency in Hz, and n is the rotational speed of the blade in r / min.

[0023] Step S2.4: Based on the main vibration frequency of each vibration velocity sensor, obtain the vibration velocity amplitude at the main vibration frequency of each vibration velocity sensor and the phase of the third vibration velocity sensor according to Equation (3).

[0024] Preferably, in Step S2, the vibration-sensitive area is the generator housing of the direct-drive wind turbine, and the rotating component is the first connecting shaft between the generator housing and the blade.

[0025] Preferably, in Step S2, the vibration-sensitive area is the first gearbox of the doubly-fed wind turbine, and the rotating component is the second connecting shaft between the first gearbox and the blade.

[0026] Preferably, in Step S3, calculate the warning value D from the vibration velocity amplitudes A and B through a formula, and compare the vibration velocity amplitude C with the warning value D to judge the consistency of the blade angles; the specific calculation method is as follows:

[0027] Step S3.1: Calculate the warning value D from the vibration velocity amplitudes A and B through Equation (1);

[0028] Step S3.2: Compare the magnitude of the warning value D with the vibration velocity amplitude C;

[0029] When C ≥ D, it indicates that there is a relatively obvious inconsistency in the blade angles of the wind turbine;

[0030] When 0.5D ≤ C < D, it indicates that there is a slight inconsistency in the blade angles of the wind turbine;

[0031] When C < 0.5D, it indicates that the blade angles of the wind turbine are consistent.

[0032] Preferably, in Step S4, when the blade angles are inconsistent, combine the phase value φ to judge the situation where a specific blade has an angle inconsistency. The specific method is as follows:

[0033] Step S4.1: Judge the lag angle θ;

[0034] When the impeller rotational speed is lower than the first critical rotational speed, judge that the range of the lag angle θ is (0°, 90°);

[0035] Step S4.2: Judge the phase φ interval;

[0036] By adding the lag angle θ to the angle of each blade, the phase φ can be obtained to be in the range of (0°, 90°) or (120°, 210°) or (240°, 330°);

[0037] Step S4.3: Determine if a specific blade angle is inconsistent. The specific method is as follows:

[0038] When φ∈(0°, 90°), the first blade has an angle inconsistent with the second and third blades;

[0039] When φ∈(120°, 210°), the angle of the second blade is inconsistent with that of the first and third blades;

[0040] If φ∈(240°, 330°), the angle of the third blade is inconsistent with that of the first and second blades.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] 1. The present invention uses three vibration velocity sensors combined with a key phase sensor to detect blade angle consistency in real time when the wind turbine is running, without the need for shutdown operations, significantly reducing power generation losses and maintenance costs.

[0043] 2. The vibration sensor and key phase sensor of the present invention are easy to install and have low cost. They do not require complex installation environment requirements and do not require entering the blade hub to perform complicated work, thus reducing labor costs.

[0044] 3. The calculation method of the present invention is based on Fourier transform and rotor dynamics theory, and the calculation is relatively convenient.

[0045] 4. The vibration sensors of the present invention are symmetrically distributed at 90° (with the third sensor as the center), and the single-point measurement error is eliminated by synthesizing the warning value D, effectively suppressing interference such as oil film vortex, and ensuring the accuracy of the calculation results. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 Schematic diagram of the method steps in the present invention;

[0047] Figure 2 It is a schematic block diagram of the workflow of the present invention;

[0048] Figure 3 Schematic diagram of the numbers and angles of the first blade, the second blade, and the third blade in the present invention;

[0049] Figure 4 This is a schematic diagram of the operation of the direct-drive blower in Example 1 of the present invention;

[0050] Figure 5This is a partial enlarged schematic diagram of point A in Example 1 of the present invention;

[0051] Figure 6 Schematic diagram of the overall installation structure of the vibration velocity sensor of Example 1 of the present invention;

[0052] Figure 7 It is a front view of the mounting structure of the vibration velocity sensor of Example 1 of the present invention;

[0053] Figure 8 It is a left side view of the mounting structure of the vibration velocity sensor of Example 1 of the present invention;

[0054] Figure 9 This is a schematic diagram of the operation of the doubly-fed wind turbine in Example 2 of the present invention;

[0055] Figure 10 This is a structural diagram of the installation position of the vibration velocity sensor of Example 2 of the present invention;

[0056] Figure 11 A front view of the installation position of the vibration velocity sensor of Example 2 of the present invention;

[0057] Figure 12 This is a left side view of the installation position of the vibration velocity sensor of Example 2 in the present invention.

[0058] In the figure: 1. First blade; 2. Second blade; 3. Third blade; 4. Key phase indicator bar; 5. Key phase sensor; 6. First speed sensor; 7. Second speed sensor; 8. Third speed sensor; 9. Generator housing; 10. First connecting shaft; 11. Second connecting shaft; 12. First gearbox. DETAILED DESCRIPTION

[0059] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0060] The present invention obtains the vibration velocity amplitudes of the three vibration velocity sensors and the phase of the third vibration velocity sensor through three vibration velocity sensors combined with a key phase sensor, judges the consistency of the blade angle according to the vibration velocity amplitude, and can judge the angle inconsistency of a specific blade in combination with the phase.

[0061] Example 1

[0062] See also Figure 1 and Figure 2 , an online detection method for the angle consistency of wind turbine blades, comprising the following steps:

[0063] Step S1: numbering the three blades of the fan as a first blade 1 , a second blade 2 and a third blade 3 respectively.

[0064] The specific operation method is: Figure 3 As shown, one of the blades is selected as the first blade 1 and the angle is set to 0°, and a key phase indicator bar 4 is taken as the key phase signal mark. The key phase signal mark includes a first blade mark and a fan speed mark. The first blade mark is used to mark the position information of the first blade, and the fan speed mark is used to record the speed information of the fan; according to the rotation direction of the direct-drive fan, the remaining two blades are numbered in sequence as the second blade 2 and the third blade 3. In this embodiment, the rotation direction of the direct-drive fan is clockwise. According to the reverse direction of the rotation of the direct-drive fan, that is, counterclockwise, the angle of the second blade 2 is set to 120°, and the angle of the third blade 3 is set to 240°.

[0065] Step S2: The vibration signals collected by the first vibration velocity sensor 6, the second vibration velocity sensor 7 and the third vibration velocity sensor 8 are combined with the key phase signal collected by the key phase sensor 5 to obtain the vibration velocity amplitudes A, B, and C of the three vibration velocity sensors and the phase φ of the third vibration velocity sensor 8, respectively. The specific method is as follows:

[0066] Step S2.1: Determine the installation positions of the vibration velocity sensor, the key phase sensor 5 and the key phase indicator bar 4.

[0067] See also Figure 4 and Figure 5 , Figure 4 This is a schematic diagram of the operation of the direct-drive fan of this embodiment during operation. Figure 5 This is a partial enlarged schematic diagram of point A in this embodiment. The key phase indicator bar 4 and the key phase sensor 5 are respectively installed on the rotating component. The orthographic projections of the axis of the key phase indicator bar 4, the axis of the key phase sensor 5, and the axis of the root of the first blade 1 on a plane parallel to the axis of the rotating component are collinear. The vibration velocity sensor is installed in the vibration-sensitive area of ​​the direct-drive wind turbine. The vibration-sensitive area is the location where the vibration signal is significant. In this embodiment, the vibration-sensitive area is the generator housing 9 of the direct-drive wind turbine. The rotating component is the first connecting shaft 10 between the generator housing and the blade. The key phase indicator bar 4 is located between the key phase sensor 5 and the blade.

[0068] See also Figure 6-8The number of vibration velocity sensors is set to three and they are numbered as the first vibration velocity sensor 6, the second vibration velocity sensor 7 and the third vibration velocity sensor 8 respectively. The three vibration velocity sensors are all located in the axial direction of the generator housing 9 and the third vibration velocity sensor 8 is located at the top of the generator housing 9. The first vibration velocity sensor 6 and the second vibration velocity sensor 7 are 90° to each other and are symmetrically distributed with the third vibration velocity sensor 8 as the center.

[0069] It is worth noting that since the fan will generate a certain amount of oil film vortex when it rotates, resulting in unequal vibration amplitudes in each direction, arranging the first vibration velocity sensor 6 and the second velocity sensor 7 separately and calculating them uniformly can effectively reduce the impact of the oil film on the fan.

[0070] Step S2.2: Collect vibration signals through three vibration velocity sensors. The specific method is as follows:

[0071] The Fourier transform of the non-periodic continuous-time signal f(t) can be expressed as:

[0072] (2)

[0073] in: is a rotation factor, j is the imaginary unit, ω is the angular frequency, rad / s, t is the time, s; X( ) is the continuous spectrum of f(t); f(t) is a non-periodic continuous time signal;

[0074] For non-periodic continuous-time signal f(t), it can be converted into:

[0075] (3)

[0076] Where f(t) is a non-periodic continuous-time signal, that is, a continuous function that changes with time; A is the vibration velocity amplitude; ψ is the corresponding phase value; n is the maximum sampling frequency of the instrument equipment, n ≥ 1; k is the frequency domain sequence number, corresponding to the actual frequency; t is the time variable, indicating the continuous change of the signal in the time domain.

[0077] Step S2.3: Obtain the blade rotation speed per minute through the key phase signal collected by the key phase sensor 5, and obtain the main vibration frequency of each vibration velocity sensor according to the rotation speed. The main frequency is calculated as follows:

[0078] (4)

[0079] Where, f is the main vibration frequency, Hz; n is the blade speed, r / min;

[0080] In this step S2.3, when the key-phase indicating bar 4 rotates to the position of the key-phase sensor 5, the key-phase sensor 5 will generate a pulse signal. For each rotation of the blade, a pulse signal will be generated. By counting the pulses, the rotational speed of the blade can be measured.

[0081] Step S2.4: Based on the vibration main frequency f of each of the vibration velocity sensors, the vibration velocity amplitudes A, B, C of the first velocity sensor 6, the second velocity sensor 7, and the third velocity sensor 8 and the phase φ of the third vibration velocity sensor 8 at the vibration main frequency f can be obtained according to Equation (3).

[0082] Step S3: Calculate the warning value D from the vibration velocity amplitudes A and B through a formula. Compare the vibration velocity amplitude C with the warning value D to judge the consistency of the blade angles. The specific method is as follows:

[0083] Step S3.1: Calculate the warning value D from the vibration velocity amplitudes A and B. The specific calculation formula is:

[0084] D = (1)

[0085] where D is the warning value, A is the vibration velocity amplitude measured by the first vibration velocity sensor 6; B is the vibration velocity amplitude measured by the second vibration velocity sensor 7;

[0086] It should be noted that in the industry, especially in Shanghai Turbine Works, this calculation method is adopted when measuring vibration. This can exclude external interference at a single point, and the value can better reflect the actual vibration of the rotor.

[0087] Step S3.2: Compare the magnitude of the warning value D with the vibration velocity amplitude C;

[0088] When C ≥ D, it indicates that there is a relatively obvious situation of inconsistent fan blade angles, and the machine needs to be stopped immediately for inspection to prevent wear of the fan.

[0089] When 0.5D ≤ C < D, it indicates that there is a slight situation of inconsistent fan blade angles, and monitoring needs to be strengthened.

[0090] When C < 0.5D, it indicates that the fan blade angles are consistent, and no adjustment needs to be made to the fan.

[0091] Step S4: When the blade angles are inconsistent, combine the phase φ to judge the situation where a specific blade has an inconsistent angle. The specific method is as follows:

[0092] Step S4.1: Judge the lag angle θ;

[0093] Since the impeller speed of a large wind turbine casing assembly generally does not exceed 20 r / min and is about 40 r / min lower than the first-order critical speed, according to rotor dynamics, the rotor lag angle below the first-order critical speed is within 90°. It can be determined that the range of the lag angle θ is (0°, 90°).

[0094] Step S4.2: Determine the phase φ interval;

[0095] Specifically, the phase interval φ can be obtained by adding the lag angle θ to the angle of each blade;

[0096] The angle of the first blade 1 is 0° + the lag angle (0°, 90°) to obtain (0°, 90°);

[0097] The angle of the second blade 2 is 120° + the lag angle (0°, 90°) to obtain (120°, 210°);

[0098] The angle of the third blade 3 is 240° + the lag angle (0°, 90°) to obtain (240°, 330°);

[0099] That is, the phase φ is in the range of (0°, 90°) or (120°, 210°) or (240°, 330°).

[0100] Step S4.3: Determine if a specific blade angle is inconsistent. The specific method is as follows:

[0101] When φ∈(0°, 90°), the first blade 1 has an angle inconsistent with the second blade 2 and the third blade 3;

[0102] When φ∈(120°, 210°), the angle of the second blade 2 is inconsistent with that of the first blade 1 and the third blade 3;

[0103] If φ∈(240°, 330°), the angle of the third blade 3 is inconsistent with that of the first blade 1 and the second blade 2.

[0104] Embodiment 1 of the present invention obtains the vibration velocity amplitude and phase through a vibration velocity sensor combined with a key phase sensor 5, judges the consistency of the blade angle according to the vibration velocity amplitude, and can judge the angle inconsistency of a specific blade in combination with the phase. The calculation method is simple and can accurately judge the blade angle.

[0105] To verify the method described in Example 1 of the present invention, this method is applied to a 2.0 MW direct-drive wind turbine. The 2.0 MW direct-drive wind turbine has large axial vibration during operation and low consistency of the long-term power curve. Please refer to Table 1, which shows the vibration velocity amplitudes A, B, C and the phase φ of the third vibration velocity sensor measured for the 2.0 MW direct-drive wind turbine.

[0106] Table 1 A, B, C and φ measured for a 2.0MW direct-drive wind turbine

[0107] Vibration velocity sensor Vibration velocity amplitude A, B, C Phase φ First vibration velocity sensor A: 3.8mm / s \ Second vibration velocity sensor B: 3.6mm / s \ The third vibration velocity sensor C:4.1mm / s Φ: 55°

[0108] (1) The vibration velocity amplitudes A and B are calculated using formula (1) to obtain the warning value D, which is 3.7 mm / s;

[0109] (2) Compare the warning value D with the vibration velocity amplitude C. If the comparison result is C>D, it means that there is a more obvious inconsistency in the fan blade angle;

[0110] (3) Finally, the phase of the third vibration velocity sensor 8 is used to determine which blade has an angle inconsistency. As shown in Table 1, φ is 55°, which falls within the interval (0°, 90°). This indicates that the first blade 1 has an angle inconsistency with the second blade 2 and the third blade 3.

[0111] A 2.0MW direct-drive wind turbine was shut down for inspection and tested using a blade angle measuring instrument. The result showed that the angle deviation between the first blade 1 and the other two blades was -7°, indicating that the angle of the first blade 1 was significantly inconsistent. This verified the calculation results of the method of Example 1 of the present invention.

[0112] Example 2

[0113] The difference between Example 2 of the present invention and Example 1 is that the wind turbine in Example 2 is a doubly-fed wind turbine. The specific differences are as follows:

[0114] See also Figure 9 As shown, the vibration sensitive area is the first gearbox 12 of the doubly fed wind turbine, and the rotating component is the second connecting shaft 11 between the first gearbox 12 and the blades; see Figure 10-12 The vibration velocity sensors are all located in the axial direction of the first gear box 12 and the third vibration velocity sensor 8 is located at the top of the first gear box 12. The key phase sensor 5 and the key phase indicator bar 4 are located on the second connecting shaft 11. In this embodiment, the second connecting shaft 11 is the same as the first connecting shaft in Example 1 and will not be repeated.

[0115] Except for the above differences, the rest of the contents are the same and will not be repeated in this embodiment 2.

[0116] To verify the method described in Example 2 of the present invention, this method is applied to a 2.65MW doubly-fed wind turbine. The 2.65MW doubly-fed wind turbine has large axial vibration during operation and low consistency of the long-term power curve. Please refer to Table 2, which shows the vibration velocity amplitudes A, B, C and the phase φ of the third vibration velocity sensor measured for the 2.65MW doubly-fed wind turbine.

[0117] Table 2 A, B, C and φ measured for a 2.65MW doubly fed wind turbine

[0118] Vibration velocity sensor Vibration velocity amplitude A, B, C Phase φ First vibration velocity sensor A: 4.2 mm / s \ Second vibration velocity sensor B: 3.5mm / s \ The third vibration velocity sensor C: 3.9mm / s Φ: 143°

[0119] (1) The vibration velocity amplitudes A and B are calculated using formula (1) to obtain the warning value D, which is 3.9 mm / s;

[0120] (2) Compare the warning value D with the vibration velocity amplitude C. The comparison result is C=D, indicating that there is a more obvious inconsistency in the fan blade angle;

[0121] (3) Finally, the phase of the third vibration velocity sensor 8 is used to determine which blade has an angle inconsistency. As shown in Table 2, φ is 143°, which falls within the interval (120°, 210°). This indicates that the angle of the second blade 2 is inconsistent with that of the first blade 1 and the third blade 3.

[0122] A 2.65MW doubly-fed wind turbine was shut down for inspection and tested using a blade angle measuring instrument. The results showed that the angle deviation between the second blade 2 and the other two blades was +5.5°, indicating that the angle of the second blade 2 was significantly inconsistent. This verified the calculation results of the method of Example 2 of the present invention.

[0123] In summary, the present invention can detect and analyze the blade status without stopping the machine, reducing the downtime and cost; the vibration velocity sensor and the key phase sensor are convenient to install, low-cost, and reusable, without the need for complex installation environment requirements, and without the need to enter the blade hub to perform complex work, reducing labor costs; the vibration velocity sensor combined with the key phase sensor can be used to determine the angle inconsistency of a specific blade, the calculation method is simple, and the blade angle can be accurately determined.

[0124] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply the existence of any such actual relationship or order between these entities or operations. Moreover, the terms "comprises," "comprising," or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article, or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or elements inherent to such process, method, article, or device. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or device comprising the element.

[0125] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. An online detection method for wind turbine blade angle consistency, characterized by: The following steps are involved: Step S1: numbering the three blades of the fan as the first blade (1), the second blade (2) and the third blade (3); Step S2: obtaining the vibration velocity amplitude and phase of the vibration velocity sensor by combining the vibration signal collected by the vibration velocity sensor with the key phase signal collected by the key phase sensor (5); the number of the vibration velocity sensors is set to three and they are numbered as the first vibration velocity sensor (6), the second vibration velocity sensor (7) and the third vibration velocity sensor (8); the vibration velocity sensors are all located in the vibration sensitive area of ​​the fan and are arranged axially, the third vibration velocity sensor (8) is located at the top of the vibration sensitive area, the first vibration velocity sensor (6) and the second vibration velocity sensor (7) are 90 degrees to each other and are symmetrically distributed with the third vibration velocity sensor (8) as the center; The key phase sensor (5) is mounted on a rotating component; the vibration velocity amplitudes of the first vibration velocity sensor (6), the second vibration velocity sensor (7), and the third vibration velocity sensor (8) are marked as A, B, and C, respectively; and the phase value of the third vibration velocity sensor (8) is marked as φ; Step S3: The vibration velocity amplitudes A and B are calculated using a formula to obtain a warning value D. The vibration velocity amplitude C is compared with the warning value D to determine the consistency of the blade angle. The calculation formula is as follows: D= （1） Wherein, D is the warning value, A is the vibration velocity amplitude measured by the first vibration velocity sensor (6); B is the vibration velocity amplitude measured by the second vibration velocity sensor (7); Step S4: If the blade angles are consistent, no adjustment is required. If the blade angles are inconsistent, the phase φ interval is used to determine whether a specific blade has an inconsistent angle. The phase φ interval is (0°, 90°) or (120°, 210°) or (240°, 330°).

2. The online detection method for wind turbine blade angle consistency according to claim 1, characterized in that: In the step S1, the three blades of the fan are numbered as the first blade (1), the second blade (2) and the third blade (3), respectively. The specific method is as follows: one of the blades is selected as the first blade (1) and the angle is set to 0°; a key phase indicator bar (4) is taken as a key phase signal mark and installed on the rotating component, and the axis of the key phase indicator bar (4), the axis of the key phase sensor (5), and the axis of the root of the first blade (1) are collinear in their orthographic projections on the surface parallel to the axis of the rotating component; the remaining two blades are numbered as the second blade (2) and the third blade (3) in sequence according to the direction of rotation of the fan, and the angle of the second blade (2) is set to 120° and the angle of the third blade (3) is set to 240° in the reverse direction of the rotation of the fan.

3. The online detection method for wind turbine blade angle consistency according to claim 1, characterized in that: In step S2, the vibration velocity amplitude and phase of the vibration velocity sensor are obtained by combining the vibration signal collected by the vibration velocity sensor with the key phase signal collected by the key phase sensor (5). The specific method is: Step S2.1: The Fourier transform of the non-periodic continuous-time signal f(t) can be expressed as: （2） in: is a rotation factor, j is the imaginary unit, ω is the angular frequency, rad / s, t is the time, s; X( ) is the continuous spectrum of f(t); f(t) is a non-periodic continuous time signal; Step S2.2: For the non-periodic continuous-time signal f(t), it can be converted into: （3） Among them, f(t) is a non-periodic continuous-time signal, that is, a continuous function varying with time; A is the vibration velocity amplitude; ψ is the corresponding phase value; n is the maximum frequency of sampling by the instrument and equipment, n≥1; k is the frequency domain serial number corresponding to the actual frequency; t is the time variable, representing the continuous change of the signal in the time domain; Step S2.3: Obtain the rotational speed of the blades per minute from the key phase signal collected by the key phase sensor (5), and obtain the vibration main frequency of each of the vibration velocity sensors according to the rotational speed. The calculation formula for the main frequency is: （4） Among them, f is the vibration main frequency, Hz; n is the rotational speed of the blades, r / min; Step S2.4: Based on the vibration main frequency of each of the vibration velocity sensors, obtain the vibration velocity amplitude at the vibration main frequency of each of the vibration velocity sensors and the phase of the third vibration velocity sensor (8) according to Equation (3).

4. The online detection method for wind turbine blade angle consistency according to claim 1, characterized in that: In the said Step S2, the vibration-sensitive area is the generator housing (9) of the direct-drive wind turbine, and the rotating component is the first connecting shaft (10) between the generator housing (9) and the blades.

5. The online detection method for wind turbine blade angle consistency according to claim 1, characterized in that: In the said Step S2, the vibration-sensitive area is the first gearbox (12) of the doubly-fed wind turbine, and the rotating component is the second connecting shaft (11) between the first gearbox (12) and the blades.

6. The online detection method for wind turbine blade angle consistency according to claim 1, characterized in that: In the said Step S3, calculate the warning value D from the vibration velocity amplitudes A and B through a formula, and compare the vibration velocity amplitude C with the warning value D to judge the consistency of the blade angles; the specific calculation method is: Step S3.1: Calculate the warning value D from the vibration velocity amplitudes A and B through formula (1); Step S3.2: Compare the magnitude of the warning value D with the vibration velocity amplitude C; When C≥D, it indicates that there is a relatively obvious condition of inconsistent blade angles of the wind turbine; When 0.5D≤C<D, it indicates that there is a slight condition of inconsistent blade angles of the wind turbine; When C<0.5D, it indicates that the blade angles of the wind turbine are consistent.

7. The online detection method for wind turbine blade angle consistency according to claim 1, characterized in that: In the said Step S4, when the blade angles are inconsistent, combine the phase value φ to judge the situation of inconsistent angles of a specific blade. The specific method is: Step S4.1: Judge the lag angle θ; When the rotational speed of the impeller is lower than the first critical rotational speed, judge that the range of the lag angle θ is (0°, 90°); Step S4.2: Judge the phase φ interval; Adding the lag angle θ to the angle of each of the blades, the interval of the phase φ can be obtained as (0°, 90°) or (120°, 210°) or (240°, 330°); Step S4.3: Judge the inconsistent angle of a specific blade. The specific method is: When φ∈(0°, 90°), that is, the first blade (1) has inconsistent angles with the second blade (2) and the third blade (3); When φ∈(120°, 210°), that is, the second blade (2) has inconsistent angles with the first blade (1) and the third blade (3); If φ∈(240°, 330°), that is, the third blade (3) has inconsistent angles with the first blade (1) and the second blade (2).

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