Online detection method for blade angle consistency of wind turbine generator

Abstract

The invention relates to the technical field of wind power generation, in particular to a wind turbine generator blade angle consistency online detection method, which comprises the following steps: numbering blades of a fan as a first blade, a second blade and a third blade; the vibration speed amplitude of each vibration sensor and the phase of the third speed sensor are obtained through vibration signals collected by the first vibration speed sensor, the second vibration speed sensor and the third vibration speed sensor and key phase signals collected by the key phase sensor; comparing the vibration speed amplitudes of the first speed sensor and the second speed sensor with an early warning value to judge the consistency of the blade angle; when the angles of the blades are inconsistent, the condition that the angles of a certain blade are inconsistent is judged according to the phase of the third vibration speed amplitude; the calculation method is simple and convenient, the blade angle consistency condition can be accurately detected, the sensor is convenient to install and low in cost, the sensor does not need to enter a blade hub for complex work, meanwhile, the blade state can be detected on line, and the shutdown time and cost are reduced.

Description

Technical Field

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

[0002] The main function of the blades of a wind turbine housing is to capture wind energy and convert it into mechanical energy, and then convert it into electrical energy through a generator. The angles of the blades should be set appropriately and the angles of the three blades should be kept consistent, so that the efficiency of the blades facing the wind is maximized, thereby ensuring the power generation efficiency of the generator; inconsistent blade angles will cause the wind turbine to not reach the optimal windward angle, resulting in a reduction in power output, and will also cause uneven rotational speed, thereby affecting the overall efficiency of the generator. If the angles of some blades are too large, it may cause the rotational speed to slow down, while the blades with too small angles may experience increased wear due to high resistance, affecting the stability and lifespan of the equipment; at the same time, inconsistent blade angles may cause the noise level to rise, affecting the quality of the surrounding environment.

[0003] In the prior art, the detection of the blade angles of a wind turbine mainly relies on the following several technologies: laser ranging and contour curve fitting technology. After retrieval, for example, a Chinese patent document discloses a method and device for detecting the blade angles of a wind turbine [Application No.: CN202410581314.9], which collects the distance data between the blade and the tower barrel in real time through a laser ranging device, generates the blade contour curve in combination with an algorithm, and calculates the twist angle and angle deviation. It is applicable to real-time monitoring in the grid-connected operation state, with high precision and no need for shutdown operation, but its cost is relatively high, and the stability requirements for the laser calibration device are high; image recognition technology: uses image processing technology combined with a deep learning model to identify the blade orientation angle. Its advantages are non-contact detection, applicability to complex lighting and dynamic scenarios, and support for remote monitoring. The disadvantages are that a large amount of model training and complex background processing are required, and the calculation accuracy is relatively low; sensor-triggered automatic zeroing system: installs sensors (such as displacement sensors or fiber optic sensors) on the hub and blades, and automatically adjusts the angle through signal feedback. The advantages are fully automated operation, applicability to large-scale units and frequent maintenance scenarios, and strong anti-interference ability. The disadvantages are that it is generally used for large-scale units, with high costs and the need for frequent maintenance; mechanical load detection method: analyzes the torque change through load sensors (such as fiber Bragg grating sensors or strain gauges) installed at the blade root. The advantages are applicability to complex mechanical environments, providing an absolute zero reference, and not relying on visual calibration. The disadvantages are that the requirements for the installation position of the sensors are relatively high, and there are many data changes during operation, requiring strong data analysis capabilities; a detection device combining machinery and laser: uses a mechanical structure in cooperation with a laser rangefinder to achieve high-precision detection. The advantages are strong portability, applicability to on-site rapid detection, and relatively low costs. The disadvantages are that it is difficult to control the accuracy of the mechanical structure and the measurement error is relatively large. Summary of the Invention

[0004] The purpose of the present invention is to provide an on-line detection method for the blade angle consistency of a wind turbine. By combining three vibration velocity sensors with a key-phase sensor, the vibration velocity amplitudes of the three vibration velocity sensors and the phase of the third vibration velocity sensor are obtained. The blade angle consistency is judged according to the vibration velocity amplitudes, and the situation of angle inconsistency of a specific blade can be judged in combination with the phase. The present invention can perform on-line real-time detection of the blade angle, reducing the downtime and cost; at the same time, the three vibration velocity sensors and the key-phase sensor are convenient to install and low in cost, without complex installation environment requirements, and without entering the blade hub for complex work, reducing the labor cost; the calculation method of the present invention is convenient and can accurately judge the blade angle situation.

[0005] To achieve the above object, the present invention provides the following technical solution: An on-line detection method for the blade angle consistency of a wind turbine, comprising the following steps:

[0006] Step S1: Number the three blades of the wind turbine as the first blade, the second blade, and the third blade respectively;

[0007] Step S2: Obtain 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. The vibration velocity sensor is installed in the vibration sensitive area of the wind turbine; the number of the vibration velocity sensors is set to three and are numbered as the first vibration velocity sensor, the second vibration velocity sensor, and the third vibration velocity sensor respectively; 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 respectively marked as A, B, and C; the phase value of the third vibration velocity sensor is marked as φ;

[0008] Step S3: Calculate the warning value D by using 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 blade angle consistency;

[0009] Step S4: If the blade angles are consistent, no adjustment is required; if the blade angles are inconsistent, combine the interval of the phase φ to judge the situation of angle inconsistency of a specific blade. The interval of the phase φ is (0°, 90°) or (120°, 210°) or (240°, 330°).

[0010] Preferably, in the step S1, the three blades of the fan are respectively numbered as the first blade, the second blade, and the third blade. The specific method is as follows: Select one of the blades and number it as the first blade and set the angle to 0°. Take a key-phase indicating bar as the key-phase signal marker and install it on the rotating component. The axes of the key-phase indicating bar, the key-phase sensor, and the root of the first blade are collinear in the orthographic projection on the plane 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 rotation direction of the fan, and set the angle of the second blade to 120° and the angle of the third blade to 240° in the reverse direction of the fan rotation.

[0011] Preferably, in the step S2, the vibration speed amplitude and phase of the vibration speed sensor are obtained by combining the vibration signal collected by the vibration speed sensor and the key-phase signal collected by the key-phase sensor. The specific method is as follows:

[0012] Step S2.1: The Fourier transform of the non-periodic continuous-time signal f(t) can be expressed as:

[0013]

[0014] where: e -jωτ is a rotation factor, j is the imaginary unit, ω is the angular frequency, in rad / s, t is the time, in s; X(ω) is the continuous spectrum of f(t); f(t) is the non-periodic continuous-time signal;

[0015] Step S2.2: For the non-periodic continuous-time signal f(t), according to the Fourier transform, it can be converted to:

[0016]

[0017] where f(t) is the non-periodic continuous-time signal, that is, a continuous function varying with time; A is the vibration speed amplitude; ψ is the corresponding phase value; n is the maximum sampling frequency of the instrument and equipment, n≥1; k is the frequency domain serial number corresponding to the actual frequency; t is the time variable indicating the continuous change of the signal in the time domain.

[0018] Step S2.3: Obtain the rotational speed of the blades per minute through the key-phase signal collected by the key-phase sensor, and obtain the vibration main frequency of each vibration speed sensor according to the rotational speed. The calculation formula for the main frequency is:

[0019] f = n / 60 (3)

[0020] where f is the vibration main frequency, in Hz; n is the rotational speed of the blade, in r / min;

[0021] 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 vibration velocity sensor and the phase of the third vibration velocity sensor according to the formula.

[0022] Preferably, in step S2, the vibration sensitive area is the generator housing of the direct-drive fan, and the rotating component is the first connecting shaft between the generator housing and the blade.

[0023] Preferably, all the vibration velocity sensors are located axially on the generator housing and the third vibration velocity sensor is located at the top of the generator housing. The first vibration velocity sensor and the second vibration velocity sensor are mutually at 90° and symmetrically distributed with the third vibration velocity sensor as the center.

[0024] Preferably, in step S2, the vibration sensitive area is the first gearbox of the doubly-fed fan, and the rotating component is the second connecting shaft between the first gearbox and the blade.

[0025] Preferably, all the vibration velocity sensors are located axially on the first gearbox and the third vibration velocity sensor is located at the top of the first gearbox. The first vibration velocity sensor and the second vibration velocity sensor are mutually at 90° and symmetrically distributed with the third vibration velocity sensor as the center.

[0026] Preferably, in step S3, calculate the warning value D from the vibration velocity amplitudes A and B through the 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, and the specific calculation formula is:

[0028]

[0029] 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;

[0030] Step S3.2: Compare the size of the warning value D with the vibration velocity amplitude C;

[0031] When C ≥ D, it indicates that there is a relatively obvious inconsistency in the blade angles of the fan;

[0032] When 0.5D ≤ C < D, it indicates that there is a slight inconsistency in the blade angles of the fan;

[0033] When C < 0.5D, it indicates that the blade angles of the fan are consistent.

[0034] Preferably, in step S4, when the blade angles are inconsistent, the specific blade with inconsistent angle is determined by combining the phase value φ. The specific method is as follows:

[0035] Step S4.1: Determine the lag angle θ;

[0036] When the impeller speed is lower than the first critical speed, it is determined that the range of the lag angle θ is (0°, 90°);

[0037] Step S4.2: Determine the phase φ interval;

[0038] Adding the lag angle θ to the angle of each blade, the obtained phase φ interval is (0°, 90°) or (120°, 210°) or (240°, 330°);

[0039] Step S4.3: Determine that a specific blade has an inconsistent angle. The specific method is as follows:

[0040] When φ ∈ (0°, 90°), it means that the first blade has an inconsistent angle with the second and third blades;

[0041] When φ ∈ (120°, 210°), it means that the second blade has an inconsistent angle with the first and third blades;

[0042] When φ ∈ (240°, 330°), it means that the third blade has an inconsistent angle with the first and second blades. Description of the Drawings

[0043] Figure 1 It is a schematic flow chart of the method steps in the present invention;

[0044] Figure 2 It is a schematic block diagram of the work flow in the present invention;

[0045] Figure 3 It is a schematic diagram of the numbers and angles of the first blade, the second blade and the third blade in the present invention;

[0046] Figure 4 It is a schematic working diagram of the direct-drive fan during operation in Embodiment 1 of the present invention;

[0047] Figure 5 It is a partial enlarged schematic diagram at A in Embodiment 1 of the present invention;

[0048] Figure 6 It is a schematic overall diagram of the installation structure of the vibration velocity sensor in Embodiment 1 of the present invention;

[0049] Figure 7 It is a front view of the installation structure of the vibration velocity sensor in Embodiment 1 of the present invention;

[0050] Figure 8 The left view of the installation structure of the vibration velocity sensor in Embodiment 1 of the present invention;

[0051] Figure 9 The working schematic diagram of the double-fed wind turbine during operation in Embodiment 2 of the present invention;

[0052] Figure 10 The structural schematic diagram of the installation position of the vibration velocity sensor in Embodiment 2 of the present invention;

[0053] Figure 11 The front view of the installation position of the vibration velocity sensor in Embodiment 2 of the present invention;

[0054] Figure 12 The left view of the installation position of the vibration velocity sensor in Embodiment 2 of the present invention.

[0055] In the figure: 1. First blade; 2. Second blade; 3. Third blade; 4. Key phase indicating bar; 5. Key phase sensor; 6. First velocity sensor; 7. Second velocity sensor; 8. Third velocity sensor; 9. Generator housing; 10. First connecting shaft; 11. Second connecting shaft; 12. First gearbox. Detailed implementation manners

[0056] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0057] The present invention obtains the vibration velocity amplitudes of three vibration velocity sensors and the phase of the third vibration velocity sensor by combining three vibration velocity sensors with a key phase sensor, judges the consistency of the blade angles according to the vibration velocity amplitudes, and can judge the situation where a specific blade has inconsistent angles in combination with the phase.

[0058] Embodiment 1

[0059] Please refer to Figure 1 and Figure 2 , an on-line detection method for the consistency of the blade angles of a wind turbine, comprising the following steps:

[0060] Step S1: Number the three blades of the wind turbine as the first blade 1, the second blade 2, and the third blade 3 respectively.

[0061] The specific operation method is: Please refer to Figure 3As shown, select one of the blades and number it as the first blade 1 and set the angle to 0°. Take a key phase indicating bar 4 as the key phase signal marker. The key phase signal marker includes a first blade marker and a fan speed marker. The first blade marker is used to mark the position information of the first blade, and the fan speed marker is used to record the speed information of the fan. According to the rotation direction of the direct-drive fan, number the remaining two blades as the second blade 2 and the third blade 3 in sequence. In this embodiment, the rotation direction of the direct-drive fan is clockwise. Set the angle of the second blade 2 to 120° and the angle of the third blade 3 to 240° in the reverse direction of the direct-drive fan rotation, i.e., counterclockwise.

[0062] Step S2: Combine the vibration signals collected by the first vibration velocity sensor 6, the second vibration velocity sensor 7, and the third vibration velocity sensor 8 with the key phase signal collected by the key phase sensor 5 to obtain the vibration velocity amplitudes A, B, 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:

[0063] Step S2.1: Determine the installation positions of the vibration velocity sensors, the key phase sensor 5, and the key phase indicating bar 4.

[0064] Please refer to Figure 4 and Figure 5 , Figure 4 which is the working schematic diagram of the direct-drive fan in this embodiment during operation. Figure 5 which is the partial enlarged schematic diagram at A in this embodiment. Install the key phase indicating bar 4 and the key phase sensor 5 on the rotating components respectively. The axes of the key phase indicating bar 4, the key phase sensor 5, and the root of the first blade 1 are collinear in the positive projection on the plane parallel to the axis of the rotating components. Install the vibration velocity sensors in the vibration-sensitive area of the direct-drive fan. The vibration-sensitive area is the part where the vibration signal is significant. In this embodiment, the vibration-sensitive area is the generator housing 9 of the direct-drive fan, and the rotating component is the first connecting shaft 10 between the generator housing and the blade. The key phase indicating bar 4 is located between the key phase sensor 5 and the blade.

[0065] Please refer to Figures 6 - 8 , the 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 axially on 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 symmetrically distributed with the third vibration velocity sensor 8 as the center.

[0066] It should be noted that since the fan will generate a certain oil film whirling when rotating, 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.

[0067] Step S2.2: Collect vibration signals through three vibration velocity sensors. The specific method is as follows:

[0068] The Fourier transform of the non-periodic continuous-time signal f(t) can be expressed as:

[0069]

[0070] where: e -jωτ is a rotation factor, j is the imaginary unit, ω is the angular frequency, rad / s, t is the time, s; X(ω) is the continuous spectrum of f(t); f(t) is the non-periodic continuous-time signal;

[0071] For the non-periodic continuous-time signal f(t), according to the Fourier transform, it can be converted to:

[0072]

[0073] where f(t) is the 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 frequency of instrument sampling, n≥1; k is the frequency domain serial number, corresponding to the actual frequency; t is the time variable, indicating the continuous change of the signal in the time domain.

[0074] Step S2.3: Obtain the rotational speed of the blades per minute through 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:

[0075] f = n / 60 (3)

[0076] where f is the vibration main frequency, Hz; n is the rotational speed of the blades, r / min;

[0077] In this step S2.3, when the key phase indicator 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 blades, a pulse signal will be generated. By counting the pulses, the rotational speed of the blades can be measured.

[0078] Step S2.4: Through the vibration main frequency f of each of the vibration velocity sensors, according to Equation (2), 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.

[0079] 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 method is as follows:

[0080] Step S3.1: Obtain the warning value D by calculating the vibration velocity amplitudes A and B. The specific calculation formula is as follows:

[0081]

[0082] 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;

[0083] 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.

[0084] Step S3.2: Compare the magnitude of the warning value D with the vibration velocity amplitude C;

[0085] When C ≥ D, it indicates that there is a relatively obvious inconsistency in the blade angles of the fan, and the machine needs to be stopped immediately for inspection to prevent wear of the fan.

[0086] When 0.5D ≤ C < D, it indicates that there is a slight inconsistency in the blade angles of the fan, and monitoring needs to be strengthened.

[0087] When C < 0.5D, it indicates that the blade angles of the fan are consistent, and no adjustment is required for the fan.

[0088] Step S4: When the blade angles are inconsistent, combine the phase φ to judge which specific blade has an inconsistent angle. The specific method is as follows:

[0089] Step S4.1: Judge the lag angle θ;

[0090] Since the rotational speed of the impeller of the large wind turbine outer casing group generally does not exceed 20 r / min, which is about 40 r / min lower than the first-order critical speed. According to rotor dynamics, the lag angle of the rotor below the first-order critical speed is within 90°. It can be judged that the range of the lag angle θ is (0°, 90°).

[0091] Step S4.2: Judge the phase φ interval;

[0092] Specifically, adding the lag angle θ to the angle of each said blade can obtain the phase φ interval;

[0093] The angle of the first blade 1, 0° + lag angle (0°, 90°), gives (0°, 90°);

[0094] The angle of the second blade 2 is 120° + lag angle (0°, 90°), resulting in (120°, 210°);

[0095] The angle of the third blade 3 is 240° + lag angle (0°, 90°), resulting in (240°, 330°);

[0096] That is, the interval of the phase φ is (0°, 90°) or (120°, 210°) or (240°, 330°).

[0097] Step S4.3: Determine that the angles of a specific blade are inconsistent. The specific method is as follows:

[0098] When φ ∈ (0°, 90°), that is, the first blade 1 has an inconsistent angle with the second blade 2 and the third blade 3;

[0099] When φ ∈ (120°, 210°), that is, the second blade 2 has an inconsistent angle with the first blade 1 and the third blade 3;

[0100] If φ ∈ (240°, 330°), that is, the third blade 3 has an inconsistent angle with the first blade 1 and the second blade 2.

[0101] In Embodiment 1 of the present invention, the vibration velocity amplitude and phase are obtained by combining a vibration velocity sensor with a key phase sensor 5. According to the vibration velocity amplitude, the consistency of the blade angles is judged, and the situation where a specific blade has an inconsistent angle can be judged in combination with the phase. The calculation method is simple and the blade angle situation can be accurately judged.

[0102] To verify the method described in Embodiment 1 of the present invention, this method is applied to a 2.0 MW direct-drive wind turbine. When the 2.0 MW direct-drive wind turbine is working, there are problems of large axial vibration and low long-term power curve consistency. 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.

[0103] Table 1 A, B, C and φ measured for a 2.0 MW direct-drive wind turbine

[0104]

[0105]

[0106] (1) The warning value D is calculated by the vibration velocity amplitudes A and B through Equation (4), and the warning value D is 3.7 mm / s;

[0107] (2) Compare the warning value D with the vibration velocity amplitude C. If the comparison result is C > D, it indicates that there is a relatively obvious situation of inconsistent fan blade angles.

[0108] (3) Finally, judge which specific blade has an inconsistent angle through the phase of the third vibration velocity sensor 8. As can be seen from Table 1, φ is 55°, which falls within the interval (0°, 90°). It can be judged that the first blade 1 has an inconsistent angle with the second blade 2 and the third blade 3.

[0109] After stopping a certain 2.0MW direct-drive fan for inspection and using a blade angle measuring instrument for testing, the angle deviation between the first blade 1 and the other two blades is -7°. That is, the angle of the first blade 1 shows an obvious inconsistency. Therefore, the calculation results of the method in Embodiment 1 of the present invention are verified.

[0110] Embodiment 2

[0111] The difference between Embodiment 2 and Embodiment 1 of the present invention is that the fan in Embodiment 2 is a doubly-fed fan. The specific differences are as follows:

[0112] Please refer to Figure 9 As shown, the vibration-sensitive area is the first gearbox 12 of the doubly-fed fan, and the rotating part is the second connecting shaft 11 between the first gearbox 12 and the blade; please refer to Figures 10 - 12 , the vibration velocity sensors are all located axially on the first gearbox 12 and the third vibration velocity sensor 8 is located at the top of the first gearbox 12. The key-phase sensor 5 and the key-phase indicating strip 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 Embodiment 1 and will not be elaborated here.

[0113] Except for the above differences, the rest of the content is the same and will not be elaborated in this Embodiment 2.

[0114] To verify the method described in Embodiment 2 of the present invention, this method is applied to a certain 2.65MW doubly-fed fan. A certain 2.65MW doubly-fed fan has a large axial vibration and a low long-term power curve consistency during operation. 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 a certain 2.65MW doubly-fed fan.

[0115] Table 2 Measured A, B, C and φ of a certain 2.65MW doubly-fed fan

[0116] Vibration velocity sensor Vibration velocity amplitudes A, B, C Phase φ First vibration velocity sensor A: 4.2 mm / s \ Second vibration velocity sensor B: 3.5 mm / s \ Third vibration velocity sensor C: 3.9 mm / s Φ: 143°

[0117] (1) Calculate the warning value D from the vibration velocity amplitudes A and B through Equation (4). The warning value D is 3.9 mm / s.

[0118] (2) Compare the warning value D with the vibration velocity amplitude C. If the comparison result is C = D, it indicates that there is a relatively obvious situation of inconsistent fan blade angles.

[0119] (3) Finally, determine which specific blade has an inconsistent angle through the phase of the third vibration velocity sensor 8. As can be seen from Table 2, φ is 143°, which falls within the interval (120°, 210°). It can be determined that the second blade 2 has an inconsistent angle with the first blade 1 and the third blade 3.

[0120] After stopping a certain 2.65MW doubly-fed fan for inspection and using a blade angle measuring instrument to test, the angle deviation between the second blade 2 and the other two blades is +5.5°. That is, the angle of the second blade 2 shows an obvious inconsistent situation. Therefore, the calculation result of the method in Embodiment 2 of the present invention is verified.

[0121] In summary, the present invention can detect and analyze the blade state without stopping the machine, reducing the downtime and cost; the installation of the vibration velocity sensor and the key phase sensor is relatively convenient, low-cost, and reusable, without complex installation environment requirements, and there is no need to enter the blade hub for complex work, reducing the labor cost; by combining the vibration velocity sensor with the key phase sensor, it can be determined which specific blade has an inconsistent angle, the calculation method is simple, and the blade angle situation can be accurately judged.

[0122] It should be noted that in this article, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements not only includes those elements, but also includes other elements not expressly listed, or also includes elements inherent to such process, method, article or device. Without further limitation, an element defined by the statement "including a..." does not exclude the existence of additional identical elements in the process, method, article or device including the said element.

[0123] Although the embodiments of the present invention have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. An online detection method for the angle consistency of wind turbine blades, characterized by: The following steps are involved: Step S1: numbering the three blades of the fan as a first blade (1), a second blade (2) and a third blade (3) respectively; 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), wherein the vibration velocity sensor is installed in the vibration sensitive area of ​​the fan; 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 key phase sensor (5) is installed on the 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: Calculate the vibration velocity amplitudes A and B through a formula to obtain a warning value D, and compare the vibration velocity amplitude C with the warning value D to determine the consistency of the blade angle; Step S4: The blade angles are consistent and no adjustment is required; if the blade angles are inconsistent, the phase φ interval is combined 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 method for online detection of 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 a 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 rotation direction 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 is 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), and the specific method is: Step S2.1: The Fourier transform of the non-periodic continuous-time signal f(t) can be expressed as: Where: e -jωτ is a rotation factor, j is an imaginary unit, ω is the angular frequency, rad / s, t is the time, s; X(ω) 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: Among them, 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, n ≥ 1; k is the frequency domain serial number, corresponding to the actual frequency; t is the time variable, indicating the continuous change of the signal in the time domain. Step S2.3: The rotation speed of the blade per minute is obtained through the key phase signal collected by the key phase sensor (5), and the main vibration frequency of each vibration velocity sensor is obtained according to the rotation speed. The main frequency is calculated as follows: f = n / 60 (3) where f is the main vibration frequency, in Hz; n is the rotational speed of the blade, in r / min; Step S2.4: Based on the main vibration frequency of each of the vibration velocity sensors, obtain the vibration velocity amplitude at the main vibration frequency of each vibration velocity sensor and the phase of the third vibration velocity sensor (8) according to Equation (2).

4. The online detection method for wind turbine blade angle consistency according to claim 1 is characterized in that: In 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 blade.

5. The online detection method for wind turbine blade angle consistency according to claim 4 is characterized in that: All of the vibration velocity sensors are located axially on 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 perpendicular to each other and symmetrically distributed around the third vibration velocity sensor (8).

6. The online detection method for wind turbine blade angle consistency according to claim 1, characterized in that: In 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 blade.

7. The online detection method for wind turbine blade angle consistency according to claim 6, characterized in that: All of the vibration velocity sensors are located axially on the first gearbox (12), and the third vibration velocity sensor (8) is located at the top of the first gearbox (12). The first vibration velocity sensor (6) and the second vibration velocity sensor (7) are perpendicular to each other and symmetrically distributed around the third vibration velocity sensor (8).

8. The online detection method for wind turbine blade angle consistency according to claim 1, characterized in that: 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: Step S3.1: Calculate the warning value D from the vibration velocity amplitudes A and B through calculation. The specific calculation formula is: 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); 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 inconsistency in the blade angles of the wind turbine; When 0.5D ≤ C < D, it indicates that there is a slight inconsistency in the blade angles of the wind turbine; When C < 0.5D, it indicates that the blade angles of the wind turbine are consistent.

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

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