Method and system for identifying wind shear working condition of wind generating set

Abstract

The invention discloses a wind shear working condition identification method and system for a wind generating set, and the method comprises the steps: obtaining the test data of the wind generating set through independent variable pitch equipment of the wind generating set, calculating the bending moment of the wind generating set in a static load coordinate system, and calculating the change rate time sequence according to the bending moment; comparing the direction and the duration of the change rate in the change rate time sequence with a preset threshold condition, and if the direction and the duration of the change rate in the change rate time sequence meet the threshold condition, identifying that the wind generating set is in a wind shear working condition; the test data can be obtained based on the independent variable pitch equipment, the difference between the wind shear working condition and the normal power generation working condition is recognized, load optimization and clearance optimization of the wind shear working condition are achieved, the generating capacity of the normal power generation working condition is not affected, and the generating capacity loss of the wind generating set is prevented.

Description

Technical Field

[0001] The present invention relates to the technical field of wind shear condition identification of a wind turbine generator set, and in particular to a method and system for wind shear condition identification of a wind turbine generator set. Background Art

[0002] Wind shear is an atmospheric phenomenon in which wind speed and direction change suddenly in the horizontal or vertical direction. Most of the domestic onshore wind farms are erected in mountainous and hilly environments, and there are more "sea and land breezes" in offshore wind farms. The wind shear of the wind farm has the characteristics of short duration, small scale and high intensity, which will cause great interference to the operation of wind turbines. Therefore, the "wind shear condition" of large wind turbines has gradually become a key condition that restricts wind turbine load and clearance.

[0003] In the prior art, laser radar is often used to detect wind shear, but it is expensive and has a narrow scope of application; or as disclosed in Chinese invention patent application CN202110725377.3, a wind turbine determines the similarity of wind speed and wind direction in the environment in which the wind turbine is located based on wind speed and wind direction sampling data, and determines that the wind turbine is in a wind shear condition based on the similarity being greater than a preset threshold. However, it is not possible to simply and effectively distinguish between the normal power generation condition and the wind shear condition of the wind turbine. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the prior art and propose a method and system for identifying wind shear conditions of a wind turbine generator set. The test data of an independent variable pitch device is converted through a stationary hub coordinate system to obtain the bending moment of the stationary hub coordinate system, and then the wind shear condition is identified through the bending moment change rate and effectively distinguished from the normal power generation condition.

[0005] The objective of the present invention is achieved through the following technical solutions: a method for identifying wind shear conditions of a wind turbine generator set, the method obtaining test data of the wind turbine generator set through an independent pitch device of the wind turbine generator set, calculating the bending moment of the wind turbine generator set in a static load coordinate system, calculating its rate of change time series based on the bending moment, comparing the direction of the rate of change and the duration in the rate of change time series with preset threshold conditions, and if the direction of the rate of change and the duration in the rate of change time series meet the threshold conditions, then the wind turbine generator set is identified as being in a wind shear condition.

[0006] Further, the method comprises the following steps:

[0007] S1. Obtain test data of the wind turbine generator set through an independent pitch control device of the wind turbine generator set;

[0008] S2. Calculate the static load coordinate system bending moments SH_My and SH_Mz of the wind turbine generator set according to the test data;

[0009] S3, obtaining the normal power generation load, the wind shear load, the SH_My change rate time series and the SH_Mz change rate time series, and then setting the threshold conditions for judging the wind shear condition as the SH_My change rate is a negative value and lasts for at least 0.8 seconds, and the SH_Mz change rate is a negative value and lasts for at least 0.8 seconds;

[0010] S4. Compare the direction and duration of the rate of change of the bending moments SH_My and SH_Mz with the threshold conditions described in step S3. If the direction and duration of the time series change rate do not meet the threshold conditions, it is considered that the wind turbine generator set is not in a wind shear condition. If the direction and duration of the time series change rate meet the threshold conditions, it is considered that the wind turbine generator set is in a wind shear condition.

[0011] Further, the step S1 comprises:

[0012] The test data include the first blade root bending moment BR_My1, the second blade root bending moment BR_My2, the third blade root bending moment BR_My3, the wind wheel azimuth angle β, the blade theoretical installation cone angle α, and the theoretical static bending moments My0 and Mz0 of the stationary hub coordinate system under gravity only.

[0013] Further, the step S2 comprises:

[0014] 1) If the impeller of the wind turbine generator set rotates counterclockwise, that is, the rotation order of the blades is the first blade, the third blade, and the second blade, the formula for calculating the static load coordinate system bending moments SH_My and SH_Mz of the wind turbine generator set is as follows:

[0015] SH_My=BR_My1*cosβ+BR_My3*cos(β-120)+BR_My2*cos(β-240)+My0;

[0016] SH_Mz=(BR_My1*sinβ+BR_My3*sin(β-120)+BR_My2*sin(β-240))*cos(α);

[0017] 2) If the impeller of the wind turbine generator set rotates clockwise, that is, the rotation order of the blades is the first blade, the second blade, and the third blade, the formula for calculating the static load coordinate system bending moments SH_My and SH_Mz of the wind turbine generator set is as follows:

[0018] SH_My=BR_My1*cosβ+BR_My2*cos(β-120)+BR_My3*cos(β-240)+My0;

[0019] SH_Mz=(BR_My1*sinβ+BR_My2*sin(β-120)+BR_My3*sin(β-240))*cos(α);

[0020] Among them, BR_My1 is the first blade root bending moment, BR_My2 is the second blade root bending moment, BR_My3 is the third blade root bending moment, β is the wind wheel azimuth, α is the theoretical installation cone angle of the blade, My0 and Mz0 are the theoretical static bending moments of the stationary hub coordinate system under gravity only.

[0021] Further, the step S3 comprises:

[0022] S3.1. Obtain the blade root load of the wind turbine generator set under normal power generation conditions and wind shear conditions, calculate the blade root loads of the two conditions, and obtain the SH_My and SH_Mz time series of the two conditions in the static load coordinate system, wherein the SH_My time series of the wind shear condition is within the maximum and minimum value range of the SH_My time series of the normal power generation condition, and the SH_Mz time series of the wind shear condition is within the maximum and minimum value range of the SH_Mz time series of the normal power generation condition, then it is determined that the wind shear condition cannot be identified based on the blade root load alone;

[0023] S3.2. According to the SH_My and SH_Mz timings of the wind turbine generator set under normal power generation conditions and wind shear conditions, respectively, the time derivative is taken to obtain the SH_My and SH_Mz timing change rates under normal power generation conditions and wind shear conditions, wherein the SH_My timing change rate under the wind shear condition is within the maximum and minimum value range of the SH_My timing change rate under the normal power generation condition, and the SH_Mz timing change rate under the wind shear condition is within the maximum and minimum value range of the SH_Mz timing change rate under the normal power generation condition, then it is determined that the wind shear condition cannot be identified only based on the SH_My and SH_Mz timing change rates;

[0024] S3.3. When the timing change rates of SH_My and SH_Mz under normal power generation conditions and wind shear conditions are negative and the duration of the negative change rates of both is not less than 0.8s, the timing change rate of SH_My under wind shear conditions is not covered by the maximum and minimum values ​​of the timing change rate of SH_My under normal power generation conditions, and the timing change rate of SH_Mz under wind shear conditions is not covered by the maximum and minimum values ​​of the timing change rate of SH_Mz under normal power generation conditions, then the judgment threshold condition is set to that the timing change rates of SH_My and SH_Mz are negative and the duration is not less than 0.8s.

[0025] A wind turbine generator set wind shear condition identification system, used to implement the wind turbine generator set wind shear condition identification method, comprising:

[0026] Independent pitch equipment for testing wind turbines;

[0027] A test data acquisition module, which acquires the test data of the wind turbine generator set by testing the independent pitch control device of the wind turbine generator set;

[0028] The static load coordinate system bending moment calculation module calculates the static load coordinate system bending moments SH_My and SH_Mz of the wind turbine generator set according to the test data;

[0029] The threshold condition setting module obtains the normal power generation load, the wind shear load, the SH_My change rate time series and the SH_Mz change rate time series, and then sets the threshold conditions for judging the wind shear condition;

[0030] The wind shear condition identification module compares the direction and duration of the change rate of the bending moments SH_My and SH_Mz with the threshold conditions of the threshold condition setting module. If the direction and duration of the time series change rate do not meet the threshold conditions, it is considered that the wind turbine is not in a wind shear condition. If the direction and duration of the time series change rate meet the threshold conditions, it is considered that the wind turbine is in a wind shear condition.

[0031] Furthermore, the test data includes a first blade root bending moment BR_My1, a second blade root bending moment BR_My2, a third blade root bending moment BR_My3, a wind rotor azimuth angle β, a blade theoretical installation cone angle α, and theoretical static bending moments My0 and Mz0 of a stationary hub coordinate system under gravity alone.

[0032] Furthermore, the static load coordinate system bending moment calculation module includes:

[0033] 1) If the impeller of the wind turbine generator set rotates counterclockwise, that is, the rotation order of the blades is the first blade, the third blade, and the second blade, the formula for calculating the static load coordinate system bending moments SH_My and SH_Mz of the wind turbine generator set is as follows:

[0034] SH_My=BR_My1*cosβ+BR_My3*cos(β-120)+BR_My2*cos(β-240)+My0;

[0035] SH_Mz=(BR_My1*sinβ+BR_My3*sin(β-120)+BR_My2*sin(β-240))*cos(α);

[0036] 2) If the impeller of the wind turbine generator set rotates clockwise, that is, the rotation order of the blades is the first blade, the second blade, and the third blade, the formula for calculating the static load coordinate system bending moments SH_My and SH_Mz of the wind turbine generator set is as follows:

[0037] SH_My=BR_My1*cosβ+BR_My2*cos(β-120)+BR_My3*cos(β-240)+My0;

[0038] SH_Mz=(BR_My1*sinβ+BR_My2*sin(β-120)+BR_My3*sin(β-240))*cos(α);

[0039] Among them, BR_My1 is the first blade root bending moment, BR_My2 is the second blade root bending moment, BR_My3 is the third blade root bending moment, β is the wind wheel azimuth, α is the theoretical installation cone angle of the blade, My0 and Mz0 are the theoretical static bending moments of the stationary hub coordinate system under gravity only.

[0040] Furthermore, the threshold condition setting module includes:

[0041] Obtain the blade root load of the wind turbine generator set under normal power generation conditions and wind shear conditions, calculate the blade root loads of the two conditions, and obtain the SH_My and SH_Mz time series of the two conditions in the static load coordinate system, wherein the SH_My time series of the wind shear condition is within the maximum and minimum value range of the SH_My time series of the normal power generation condition, and the SH_Mz time series of the wind shear condition is within the maximum and minimum value range of the SH_Mz time series of the normal power generation condition, then it is determined that the wind shear condition cannot be identified based on the blade root load alone;

[0042] According to the SH_My and SH_Mz timings of the wind turbine generator set under normal power generation conditions and wind shear conditions, the time derivative is respectively taken to obtain the SH_My and SH_Mz timing change rates under normal power generation conditions and wind shear conditions, wherein the SH_My timing change rate under the wind shear condition is within the maximum and minimum value range of the SH_My timing change rate under the normal power generation condition, and the SH_Mz timing change rate under the wind shear condition is within the maximum and minimum value range of the SH_Mz timing change rate under the normal power generation condition, then it is determined that the wind shear condition cannot be identified only based on the SH_My and SH_Mz timing change rates;

[0043] When the timing change rates of SH_My and SH_Mz under normal power generation conditions and wind shear conditions are negative and the duration of the negative change rates of both is not less than 0.8s, the timing change rate of SH_My under wind shear conditions is not covered by the maximum and minimum values ​​of the timing change rate of SH_My under normal power generation conditions, and the timing change rate of SH_Mz under wind shear conditions is not covered by the maximum and minimum values ​​of the timing change rate of SH_Mz under normal power generation conditions. The judgment threshold condition is set to that the timing change rates of SH_My and SH_Mz are negative and the duration is not less than 0.8s.

[0044] Furthermore, the wind shear condition identification module includes:

[0045] The direction and duration of the change rate of the bending moments SH_My and SH_Mz are compared with the threshold conditions of the threshold condition setting module. If the direction and duration of the timing change rate do not meet the requirements that the timing change rate is a negative value and the duration is not less than 0.8s, the wind turbine is considered not to be in a wind shear condition. If the direction and duration of the timing change rate meet the requirements that the timing change rate is a negative value and the duration is not less than 0.8s, the wind turbine is considered to be in a wind shear condition.

[0046] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0047] (1) The present invention can obtain test data based on independent pitch devices and identify the differences between wind shear conditions and normal power generation conditions. It can achieve load optimization and clearance optimization under wind shear conditions without affecting the power generation under normal power generation conditions, thus preventing the wind turbine generator set from losing power.

[0048] (2) The present invention can detect wind shear conditions using test data from existing independent variable pitch equipment, with low cost and wide applicability. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 Schematic diagram of the stationary hub coordinate system of a wind turbine.

[0050] Figure 2 It is the timing diagram of the bending moment SH_My in the stationary hub coordinate system.

[0051] Figure 3 It is the timing diagram of the changing rate of the bending moment SH_My in the stationary hub coordinate system.

[0052] Figure 4 For Figure 3 Schematic diagram of wind shear conditions selected and identified based on threshold conditions. DETAILED DESCRIPTION

[0053] The present invention will be further described below in conjunction with specific embodiments.

[0054] Example 1

[0055] The present embodiment provides a method for identifying a wind shear condition of a wind turbine generator set. The method is to obtain test data of the wind turbine generator set through an independent pitch device of the wind turbine generator set, calculate the bending moment of the wind turbine generator set in a static load coordinate system, calculate the change rate time series according to the bending moment, compare the direction and duration of the change rate in the change rate time series with a preset threshold condition, and if the direction and duration of the change rate in the change rate time series meet the threshold condition, identify that the wind turbine generator set is in a wind shear condition, and include the following steps:

[0056] S1. Obtain the test data of the wind turbine generator set through the blade root load independent pitch device of the wind turbine generator set; the test data includes the first blade root bending moment BR_My1, the second blade root bending moment BR_My2, the third blade root bending moment BR_My3, the wind rotor azimuth angle β, the blade theoretical installation cone angle α and the theoretical static bending moments My0 and Mz0 of the stationary hub coordinate system under gravity only.

[0057] S2, see Figure 1 As shown in the figure, it is a schematic diagram of the stationary hub coordinate system of the wind turbine generator set, where: XN is the axis along the rotor axis, ZN is the axis perpendicular to the XN direction, YN is the horizontal axis and forms a right-handed coordinate system with the XN axis and the ZN axis, F XN 、F YN 、F ZN are the tensile forces along the XN, YN and ZN axes, M XN 、M YN and M ZN are the bending moments in the positive directions around the XN, YN and ZN axes respectively, and the positive directions around the XN, YN and ZN axes are clockwise;

[0058] According to the test data, the YN axis and ZN axis bending moments SH_My (M YN ) and SH_Mz(M ZN );

[0059] 1) If the impeller of the wind turbine generator set rotates counterclockwise, that is, the rotation order of the blades is the first blade, the third blade, and the second blade, the formula for calculating the static load coordinate system bending moments SH_My and SH_Mz of the wind turbine generator set is as follows:

[0060] SH_My=BR_My1*cosβ+BR_My3*cos(β-120)+BR_My2*cos(β-240)+My0;

[0061] SH_Mz=(BR_My1*sinβ+BR_My3*sin(β-120)+BR_My2*sin(β-240))*cos(α);

[0062] 2) If the impeller of the wind turbine generator set rotates clockwise, that is, the rotation order of the blades is the first blade, the second blade, and the third blade, the formula for calculating the static load coordinate system bending moments SH_My and SH_Mz of the wind turbine generator set is as follows:

[0063]

[0064] S3, obtaining the normal power generation load, wind shear load, and SH_My change rate time series, and then setting the threshold condition for judging the wind shear condition as the SH_My change rate is negative and lasts for at least 0.8 seconds, including:

[0065] S3.1. Obtain the blade root load of the wind turbine generator set under normal power generation conditions and wind shear conditions, calculate the blade root loads of the two conditions, and obtain the SH_My time series in the static load coordinate system of the two conditions, see Figure 2 As shown, the SH_My timing of the wind shear condition is within the maximum and minimum range of the SH_My timing of the normal power generation condition, and it is determined that the wind shear condition cannot be identified based on the blade root load alone;

[0066] S3.2. According to the SH_My of the wind turbine generator set under normal power generation conditions and wind shear conditions, the time derivative is respectively obtained to obtain the time series change rate of SH_My under normal power generation conditions and wind shear conditions, see Figure 3 As shown, the SH_My time series change rate of the wind shear condition is within the maximum and minimum value range of the SH_My time series change rate of the normal power generation condition, and it is determined that the wind shear condition cannot be identified only based on the SH_My time series change rate;

[0067] S3.3. To prevent the SH_My time series change rate of wind shear condition from being covered by the maximum and minimum values ​​of the SH_My time series change rate of normal power generation condition, it is necessary to superimpose the two conditions of the direction of the time series change rate and the time threshold. Since the closed-loop control of the wind turbine control logic, i.e. receiving signals, logical judgment and then transmitting control instructions, takes about 120ms, the judgment threshold condition is set to a negative value of the SH_My time series change rate and a duration of not less than 0.8s; see Figure 4 As shown in the figure, the SH_My timing change rate at point A is negative and lasts for 5s, which meets the threshold condition, so that the SH_My timing change rate of the wind shear condition is not covered by the maximum and minimum values ​​of the SH_My timing change rate of the normal power generation condition, and can be used to identify the wind shear condition.

[0068] In the stationary hub coordinate system, the SH_Mz load and the SH_My load belong to the axisymmetric bending moment of the X-axis, so the relevant strategy for identifying the wind shear condition through the SH_Mz load is consistent with the SH_My method.

[0069] S4. Compare the direction and duration of the rate of change of the bending moments SH_My and SH_Mz with the threshold conditions described in step S3. If the direction and duration of the time series change rate do not meet the threshold conditions, it is considered that the wind turbine generator set is not in a wind shear condition. If the direction and duration of the time series change rate meet the threshold conditions, it is considered that the wind turbine generator set is in a wind shear condition.

[0070] Example 2

[0071] This embodiment discloses a wind shear condition identification system for a wind turbine generator set, which is used to implement the wind shear condition identification method for a wind turbine generator set described in Embodiment 1, including:

[0072] Independent pitch equipment for testing wind turbines;

[0073] The test data acquisition module acquires the test data of the wind turbine generator set by testing the independent variable pitch device of the wind turbine generator set; the test data includes the first blade root bending moment BR_My1, the second blade root bending moment BR_My2, the third blade root bending moment BR_My3, the wind wheel azimuth angle β, the blade theoretical installation cone angle α and the theoretical static bending moments My0 and Mz0 of the stationary hub coordinate system under gravity only.

[0074] The static load coordinate system bending moment calculation module calculates the static load coordinate system bending moments SH_My and SH_Mz of the wind turbine generator set according to the test data, including:

[0075] 1) If the impeller of the wind turbine generator set rotates counterclockwise, that is, the rotation order of the blades is the first blade, the third blade, and the second blade, the formula for calculating the static load coordinate system bending moments SH_My and SH_Mz of the wind turbine generator set is as follows:

[0076] SH_My=BR_My1*cosβ+BR_My3*cos(β-120)+BR_My2*cos(β-240)+My0;

[0077] SH_Mz=(BR_My1*sinβ+BR_My3*sin(β-120)+BR_My2*sin(β-240))*cos(α);

[0078] 2) If the impeller of the wind turbine generator set rotates clockwise, that is, the rotation order of the blades is the first blade, the second blade, and the third blade, the formula for calculating the static load coordinate system bending moments SH_My and SH_Mz of the wind turbine generator set is as follows:

[0079]

[0080] The threshold condition setting module obtains the normal power generation load, wind shear load, SH_My change rate time series and SH_Mz change rate time series, and then sets the threshold conditions for judging the wind shear condition, including:

[0081] Obtain the blade root load of the wind turbine generator set under normal power generation conditions and wind shear conditions, calculate the blade root loads of the two conditions, and obtain the SH_My and SH_Mz time series of the two conditions in the static load coordinate system, wherein the SH_My time series of the wind shear condition is within the maximum and minimum value range of the SH_My time series of the normal power generation condition, and the SH_Mz time series of the wind shear condition is within the maximum and minimum value range of the SH_Mz time series of the normal power generation condition, then it is determined that the wind shear condition cannot be identified based on the blade root load alone;

[0082] According to the SH_My and SH_Mz timings of the wind turbine generator set under normal power generation conditions and wind shear conditions, the time derivative is respectively taken to obtain the SH_My and SH_Mz timing change rates under normal power generation conditions and wind shear conditions, wherein the SH_My timing change rate under the wind shear condition is within the maximum and minimum value range of the SH_My timing change rate under the normal power generation condition, and the SH_Mz timing change rate under the wind shear condition is within the maximum and minimum value range of the SH_Mz timing change rate under the normal power generation condition, then it is determined that the wind shear condition cannot be identified only based on the SH_My and SH_Mz timing change rates;

[0083] When the timing change rates of SH_My and SH_Mz under normal power generation conditions and wind shear conditions are negative and the duration of the negative change rates of both is not less than 0.8s, the timing change rate of SH_My under wind shear conditions is not covered by the maximum and minimum values ​​of the timing change rate of SH_My under normal power generation conditions, and the timing change rate of SH_Mz under wind shear conditions is not covered by the maximum and minimum values ​​of the timing change rate of SH_Mz under normal power generation conditions. The judgment threshold condition is set to that the timing change rates of SH_My and SH_Mz are negative and the duration is not less than 0.8s.

[0084] The wind shear condition identification module compares the direction and duration of the change rate of the bending moments SH_My and SH_Mz with the threshold conditions of the threshold condition setting module. If the direction and duration of the timing change rate do not meet the requirements that the timing change rate is a negative value and the duration is not less than 0.8s, the wind turbine is considered not to be in a wind shear condition. If the direction and duration of the timing change rate meet the requirements that the timing change rate is a negative value and the duration is not less than 0.8s, the wind turbine is considered to be in a wind shear condition.

[0085] Example 3

[0086] This embodiment discloses a non-transitory computer-readable medium storing instructions. When the instructions are executed by a processor, the steps of the method for identifying wind shear conditions of a wind turbine generator set according to Embodiment 1 are executed.

[0087] The non-temporary computer-readable medium in this embodiment may be a disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), a USB flash drive, a mobile hard disk, or other media.

[0088] Example 4

[0089] This embodiment discloses a computing device, including a processor and a memory for storing a program executable by the processor. When the processor executes the program stored in the memory, the method for identifying wind shear conditions of a wind turbine generator set described in Embodiment 1 is implemented.

[0090] The computing device described in this embodiment may be a desktop computer, a laptop computer, a smart phone, a PDA handheld terminal, a tablet computer, a programmable logic controller (PLC), or other terminal devices with a processor function.

[0091] The embodiments described above are only preferred embodiments of the present invention and are not intended to limit the scope of implementation of the present invention. Therefore, all changes made according to the shape and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for identifying wind shear conditions of a wind turbine generator set, characterized in that: The method is to obtain the test data of the wind turbine generator set through the independent pitch device of the wind turbine generator set, calculate the bending moment of the wind turbine generator set in the static load coordinate system, calculate its change rate time series according to the bending moment, compare the direction of the change rate and the duration in the change rate time series with the preset threshold conditions, and if the direction of the change rate and the duration in the change rate time series meet the threshold conditions, it is identified that the wind turbine generator set is in a wind shear condition.

2. A method for identifying wind shear conditions of a wind turbine generator set according to claim 1, characterized in that: The following steps are involved: S1. Obtain test data of the wind turbine generator set through an independent pitch control device of the wind turbine generator set; S2. Calculate the static load coordinate system bending moments SH_My and SH_Mz of the wind turbine generator set according to the test data; S3, obtaining the normal power generation load, the wind shear load, the SH_My change rate time series and the SH_Mz change rate time series, and then setting the threshold conditions for judging the wind shear condition as the SH_My change rate is a negative value and lasts for at least 0.8 seconds, and the SH_Mz change rate is a negative value and lasts for at least 0.8 seconds; S4. Compare the direction and duration of the rate of change of the bending moments SH_My and SH_Mz with the threshold conditions described in step S3. If the direction and duration of the time series change rate do not meet the threshold conditions, it is considered that the wind turbine generator set is not in a wind shear condition. If the direction and duration of the time series change rate meet the threshold conditions, it is considered that the wind turbine generator set is in a wind shear condition.

3. A method for identifying wind shear conditions of a wind turbine generator set according to claim 2, characterized in that: The step S1 comprises: The test data include the first blade root bending moment BR_My1, the second blade root bending moment BR_My2, the third blade root bending moment BR_My3, the wind wheel azimuth angle β, the blade theoretical installation cone angle α, and the theoretical static bending moments My0 and Mz0 of the stationary hub coordinate system under gravity only.

4. A method for identifying wind shear conditions of a wind turbine generator set according to claim 2, characterized in that: The step S2 comprises: 1) If the impeller of the wind turbine generator set rotates counterclockwise, that is, the rotation order of the blades is the first blade, the third blade, and the second blade, the formula for calculating the static load coordinate system bending moments SH_My and SH_Mz of the wind turbine generator set is as follows: SH_My=BR_My1*cosβ+BR_My3*cos(β-120)+BR_My2*cos(β-240)+My0; SH_Mz=(BR_My1*sinβ+BR_My3*sin(β-120)+BR_My2*sin(β-240))*cos(α); 2) If the impeller of the wind turbine generator set rotates clockwise, that is, the rotation order of the blades is the first blade, the second blade, and the third blade, the formula for calculating the static load coordinate system bending moments SH_My and SH_Mz of the wind turbine generator set is as follows: SH_My=BR_My1*cosβ+BR_My2*cos(β-120)+BR_My3*cos(β-240)+My0; SH_Mz=(BR_My1*sinβ+BR_My2*sin(β-120)+BR_My3*sin(β-240))*cos(α); Among them, BR_My1 is the first blade root bending moment, BR_My2 is the second blade root bending moment, BR_My3 is the third blade root bending moment, β is the wind wheel azimuth, α is the theoretical installation cone angle of the blade, My0 and Mz0 are the theoretical static bending moments of the stationary hub coordinate system under gravity only.

5. A method for identifying wind shear conditions of a wind turbine generator set according to claim 2, characterized in that: The step S3 comprises: S3.

1. Obtain the blade root load of the wind turbine generator set under normal power generation conditions and wind shear conditions, calculate the blade root loads of the two conditions, and obtain the SH_My and SH_Mz time series of the two conditions in the static load coordinate system, wherein the SH_My time series of the wind shear condition is within the maximum and minimum value range of the SH_My time series of the normal power generation condition, and the SH_Mz time series of the wind shear condition is within the maximum and minimum value range of the SH_Mz time series of the normal power generation condition, then it is determined that the wind shear condition cannot be identified based on the blade root load alone; S3.

2. According to the SH_My and SH_Mz timings of the wind turbine generator set under normal power generation conditions and wind shear conditions, respectively, the time derivative is taken to obtain the SH_My and SH_Mz timing change rates under normal power generation conditions and wind shear conditions, wherein the SH_My timing change rate under the wind shear condition is within the maximum and minimum value range of the SH_My timing change rate under the normal power generation condition, and the SH_Mz timing change rate under the wind shear condition is within the maximum and minimum value range of the SH_Mz timing change rate under the normal power generation condition, then it is determined that the wind shear condition cannot be identified only based on the SH_My and SH_Mz timing change rates; S3.

3. When the timing change rates of SH_My and SH_Mz under normal power generation conditions and wind shear conditions are negative and the duration of the negative change rates of both is not less than 0.8s, the timing change rate of SH_My under wind shear conditions is not covered by the maximum and minimum values ​​of the timing change rate of SH_My under normal power generation conditions, and the timing change rate of SH_Mz under wind shear conditions is not covered by the maximum and minimum values ​​of the timing change rate of SH_Mz under normal power generation conditions, then the judgment threshold condition is set to that the timing change rates of SH_My and SH_Mz are negative and the duration is not less than 0.8s.

6. A wind shear condition identification system for a wind turbine generator set, characterized in that: A method for identifying wind shear conditions of a wind turbine generator set according to any one of claims 1 to 5, comprising: Independent pitch equipment for testing wind turbines; A test data acquisition module, which acquires the test data of the wind turbine generator set by testing the independent pitch control device of the wind turbine generator set; The static load coordinate system bending moment calculation module calculates the static load coordinate system bending moments SH_My and SH_Mz of the wind turbine generator set according to the test data; The threshold condition setting module obtains the normal power generation load, the wind shear load, the SH_My change rate time series and the SH_Mz change rate time series, and then sets the threshold conditions for judging the wind shear condition; The wind shear condition identification module compares the direction and duration of the change rate of the bending moments SH_My and SH_Mz with the threshold conditions of the threshold condition setting module. If the direction and duration of the time series change rate do not meet the threshold conditions, it is considered that the wind turbine is not in a wind shear condition. If the direction and duration of the time series change rate meet the threshold conditions, it is considered that the wind turbine is in a wind shear condition.

7. A wind turbine generator set wind shear condition identification system according to claim 6, characterized in that: The test data include the first blade root bending moment BR_My1, the second blade root bending moment BR_My2, the third blade root bending moment BR_My3, the wind wheel azimuth angle β, the blade theoretical installation cone angle α, and the theoretical static bending moments My0 and Mz0 of the stationary hub coordinate system under gravity only.

8. A wind turbine generator set wind shear condition identification system according to claim 6, characterized in that: The static load coordinate system bending moment calculation module includes: 1) If the impeller of the wind turbine generator set rotates counterclockwise, that is, the rotation order of the blades is the first blade, the third blade, and the second blade, the formula for calculating the static load coordinate system bending moments SH_My and SH_Mz of the wind turbine generator set is as follows: SH_My=BR_My1*cosβ+BR_My3*cos(β-120)+BR_My2*cos(β-240)+My0; SH_Mz=(BR_My1*sinβ+BR_My3*sin(β-120)+BR_My2*sin(β-240))*cos(α); 2) If the impeller of the wind turbine generator set rotates clockwise, that is, the rotation order of the blades is the first blade, the second blade, and the third blade, the formula for calculating the static load coordinate system bending moments SH_My and SH_Mz of the wind turbine generator set is as follows: SH_My=BR_My1*cosβ+BR_My2*cos(β-120)+BR_My3*cos(β-240)+My0; SH_Mz=(BR_My1*sinβ+BR_My2*sin(β-120)+BR_My3*sin(β-240))*cos(α); Among them, BR_My1 is the first blade root bending moment, BR_My2 is the second blade root bending moment, BR_My3 is the third blade root bending moment, β is the wind wheel azimuth, α is the theoretical installation cone angle of the blade, My0 and Mz0 are the theoretical static bending moments of the stationary hub coordinate system under gravity only.

9. A wind turbine generator set wind shear condition identification system according to claim 6, characterized in that: The threshold condition setting module includes: Obtain the blade root load of the wind turbine generator set under normal power generation conditions and wind shear conditions, calculate the blade root loads of the two conditions, and obtain the SH_My and SH_Mz time series of the two conditions in the static load coordinate system, wherein the SH_My time series of the wind shear condition is within the maximum and minimum value range of the SH_My time series of the normal power generation condition, and the SH_Mz time series of the wind shear condition is within the maximum and minimum value range of the SH_Mz time series of the normal power generation condition, then it is determined that the wind shear condition cannot be identified based on the blade root load alone; According to the SH_My and SH_Mz timings of the wind turbine generator set under normal power generation conditions and wind shear conditions, the time derivative is respectively taken to obtain the SH_My and SH_Mz timing change rates under normal power generation conditions and wind shear conditions, wherein the SH_My timing change rate under the wind shear condition is within the maximum and minimum value range of the SH_My timing change rate under the normal power generation condition, and the SH_Mz timing change rate under the wind shear condition is within the maximum and minimum value range of the SH_Mz timing change rate under the normal power generation condition, then it is determined that the wind shear condition cannot be identified only based on the SH_My and SH_Mz timing change rates; When the timing change rates of SH_My and SH_Mz under normal power generation conditions and wind shear conditions are negative and the duration of the negative change rates of both is not less than 0.8s, the timing change rate of SH_My under wind shear conditions is not covered by the maximum and minimum values ​​of the timing change rate of SH_My under normal power generation conditions, and the timing change rate of SH_Mz under wind shear conditions is not covered by the maximum and minimum values ​​of the timing change rate of SH_Mz under normal power generation conditions. The judgment threshold condition is set to that the timing change rates of SH_My and SH_Mz are negative and the duration is not less than 0.8s.

10. A wind turbine generator set wind shear condition identification system according to claim 6, characterized in that: The wind shear condition identification module includes: The direction and duration of the change rate of the bending moments SH_My and SH_Mz are compared with the threshold conditions of the threshold condition setting module. If the direction and duration of the timing change rate do not meet the requirements that the timing change rate is a negative value and the duration is not less than 0.8s, the wind turbine is considered not to be in a wind shear condition. If the direction and duration of the timing change rate meet the requirements that the timing change rate is a negative value and the duration is not less than 0.8s, the wind turbine is considered to be in a wind shear condition.

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