CN112746929B

CN112746929B - Blade stall monitoring method, device, equipment and storage medium

Info

Publication number: CN112746929B
Application number: CN201911063159.7A
Authority: CN
Inventors: 陈威; 杨建军
Original assignee: Jiangsu Goldwind Science and Technology Co Ltd
Current assignee: Jiangsu Goldwind Science and Technology Co Ltd
Priority date: 2019-10-31
Filing date: 2019-10-31
Publication date: 2022-07-26
Anticipated expiration: 2039-10-31
Also published as: CN112746929A

Abstract

The invention provides a method, a device, equipment and a storage medium for monitoring blade stall, and relates to the field of wind power generation. The blade stall monitoring method comprises the following steps: measuring and calculating the attack angle of one or more sections of the blade of the wind generating set; determining a stall attack angle critical value corresponding to the section according to the pneumatic parameters of the section; and if the attack angle of at least one section is larger than the stalling attack angle critical value corresponding to at least one section, judging that the wind generating set has blade stalling. By utilizing the technical scheme of the invention, the monitoring on the blade stall of the wind generating set can be realized, and the operation reliability of the wind generating set is improved.

Description

Blade stall monitoring method, device, equipment and storage medium

Technical Field

The invention belongs to the field of wind power generation, and particularly relates to a method, a device, equipment and a storage medium for monitoring blade stall.

Background

The wind generating set is in a normal working condition, the attack angle of the blade of the wind generating set is very small, and airflow can bypass the blade to keep a streamline state. When the angle of attack of the blade is too large, the lift coefficient decreases with the increase of the angle of attack, that is, the stall phenomenon of the blade occurs. In the event of a blade stall, the aerodynamic damping of the blade is negative and the aerodynamic effects may exacerbate the vibration effects of the blade, thereby causing damage to the blade.

Therefore, in order to ensure the safety of the wind generating set, a blade stall monitoring method is urgently needed to monitor the blade stall phenomenon of the wind generating set.

Disclosure of Invention

The embodiment of the invention provides a method, a device, equipment and a storage medium for monitoring blade stall, which can be used for monitoring the blade stall of a wind generating set and improving the operation reliability of the wind generating set.

In a first aspect, an embodiment of the present invention provides a blade stall monitoring method, including: measuring and calculating the attack angle of one or more sections of the blade of the wind generating set; determining a stall attack angle critical value corresponding to the section according to the pneumatic parameters of the section; and if the attack angle of at least one section is larger than the stall attack angle critical value corresponding to at least one section, judging that the blade stall occurs in the wind generating set.

In some possible embodiments, estimating an angle of attack of one or more sections of a blade of a wind park, comprises: and aiming at one section, acquiring environmental parameters, blade operating parameters and axial induction factors, and calculating to obtain the attack angle of the section according to the environmental parameters, the blade operating parameters and the axial induction factors.

In some possible embodiments, the blade operational parameters include a wind direction angle, a distance between the cross section and a center of a hub of the wind park, an impeller rotation speed of the wind park, an intrinsic twist angle value of the cross section, a pitch angle of the blade, and a torsional deformation amount of the blade; or the blade operation parameters comprise a wind direction angle, a distance between the section and the center of a hub of the wind generating set, an impeller rotating speed of the wind generating set, an inherent torsion angle value of the section, a pitch angle of the blade, a torsion deformation amount of the blade and a blade tip loss of the blade.

In some possible embodiments, the environmental parameter comprises wind speed, or the environmental parameter comprises wind speed and one or more of: temperature, air density, liquid water content, weather factors.

In some possible embodiments, if the angle of attack of at least one section is greater than the stall angle of attack threshold value corresponding to the at least one section, determining that the wind turbine generator system has blade stall includes: and if the attack angle of at least one section is larger than the stall attack angle critical value corresponding to at least one section and the attack angle of at least one section meets the N-stage stall condition, judging that the wind generating set has N-stage blade stall, wherein N is a positive integer.

In some possible embodiments, after the above determining that the blade stall of the wind turbine generator system occurs, the method further includes:

and executing an N-stage blade stall strategy corresponding to the N-stage blade stall to prompt the wind generating set of the blade stall or control the wind generating set to adjust the operation state so that the attack angle of at least one section is reduced.

In some possible embodiments, where N is 1, the primary stall condition comprises: the attack angle of the cross section is larger than a first attack angle threshold value, the duration of the time that the attack angle of the cross section is larger than the first attack angle threshold value exceeds a first duration threshold value, and the first attack angle threshold value is larger than a stall attack angle critical value corresponding to the cross section;

n-2, the secondary stall conditions include: the attack angle of the cross section is larger than a first attack angle threshold value and smaller than or equal to a second attack angle threshold value, the duration of the attack angle of the cross section, which is larger than the first attack angle threshold value and smaller than or equal to the second attack angle threshold value, exceeds a second duration threshold value, the second attack angle threshold value is larger than the first attack angle threshold value, and the second duration threshold value is larger than the first duration threshold value;

n-3, the three-stage stall condition includes: the attack angle of the cross section is larger than a second attack angle threshold value, and the duration of the attack angle of the cross section larger than the second attack angle threshold value is larger than a second duration threshold value; or the attack angle of the cross section is greater than the third attack angle threshold, the duration that the attack angle of the cross section is greater than the third attack angle threshold exceeds the third duration threshold, the third attack angle threshold is greater than the second attack angle threshold, and the third duration threshold is less than the second duration threshold.

under the condition that the blade stall is the first-stage blade stall, executing a first-stage blade stall strategy corresponding to the first-stage blade stall, and sending early warning information to a central controller corresponding to the wind generating set;

under the condition that the blade stall is the second-stage blade stall, executing a second-stage blade stall strategy corresponding to the second-stage blade stall, and sending a first control instruction to a stall regulation structure of the wind generating set, wherein the first control instruction is used for instructing the stall regulation structure to regulate the wind generating set so as to reduce the attack angle of at least one section;

and under the condition that the blade stall is the three-stage blade stall, executing a three-stage blade stall strategy corresponding to the three-stage blade stall, and sending a stop instruction to the wind generating set, wherein the stop instruction is used for indicating the wind generating set to stop.

In some possible embodiments, the ratio of the distance of the at least one section from the root of the blade to the length of the blade is above a stall withstand length ratio threshold.

and under the condition that the blade stall is the three-stage blade stall, executing a three-stage blade stall strategy corresponding to the three-stage blade stall, and sending a second control command to a stall regulation and control structure of the wind generating set, wherein the second control command is used for instructing the stall regulation and control structure to adjust the wind generating set so as to reduce the attack angle of at least one section.

In some possible embodiments, the ratio of the distance of the at least one section from the root of the blade to the length of the blade is lower than or equal to a stall tolerance length ratio threshold.

In some possible embodiments, the stall regulation structure comprises a pitch system of the wind park, the first control instructions being for instructing an increase of a pitch angle of the blades of the wind park; and/or the stall regulation structure comprises an aerodynamic profile adjustment device of the blade, and the first control instruction is used for instructing to change the aerodynamic profile of the blade.

In a second aspect, embodiments of the present invention provide a method for monitoring blade stall, which is applied to a wind turbine group, where the wind turbine group includes a plurality of wind turbine generators,

the blade stall monitoring method comprises the following steps: determining a target wind generating set of the outermost periphery of the wind generating set group, which is subjected to blade stall, by using the blade stall monitoring method in the technical scheme in the first aspect; and predicting whether the downwind wind generating set is about to have blade stall or not according to the windward angle of the target wind generating set and the windward angle of the downwind wind generating set, wherein the downwind wind generating set is the downwind wind generating set of the target wind generating set.

In some possible embodiments, predicting whether a downwind wind park is about to suffer from blade stall based on a wind angle of the target wind park and a wind angle of the downwind wind park, comprises: and if the difference value of the wind angle of the target wind generating set and the wind angle of the downwind wind generating set is within the stall difference value threshold range, predicting that the wind generating set closest to the target wind generating set in the downwind wind generating set is about to have blade stall.

In some possible embodiments, the above blade stall monitoring method further includes: calculating the first time of the wind at the current moment from the target wind generating set to the downwind wind generating set which predicts the impending blade stall; executing a blade stall strategy corresponding to the target wind generating set on the target wind generating set; before the first time, the same blade stall strategy as the corresponding blade stall strategy of the target wind park is performed on the downwind wind park where blade stall is predicted to be imminent.

In a third aspect, an embodiment of the present invention provides a blade stall monitoring apparatus, including: the measuring and calculating module is used for measuring and calculating the attack angle of one or more sections of the blade of the wind generating set; the determining module is used for determining a stall attack angle critical value corresponding to the section according to the pneumatic parameters of the section; and the stall determination module is used for determining that the blade stall occurs in the wind generating set if the attack angle of at least one section is larger than the stall attack angle critical value corresponding to at least one section.

In some possible embodiments, the blade stall comprises N stages of blade stall, the apparatus further comprising:

and the execution module is used for executing an N-stage blade stall strategy corresponding to the N-stage blade stall so as to prompt the wind generating set to have the blade stall or control the wind generating set to adjust the operation state so that the attack angle of at least one section is reduced.

In a fourth aspect, an embodiment of the present invention provides a blade stall monitoring apparatus, including: a target determining module, configured to determine, by using the blade stall monitoring method according to the technical scheme in the first aspect, a target wind turbine generator set at an outermost periphery of the wind turbine generator set group where blade stall occurs; and the prediction module is used for predicting whether the downwind wind generating set is about to have blade stall or not according to the windward angle of the target wind generating set and the windward angle of the downwind wind generating set, and the downwind wind generating set is the downwind wind generating set of the target wind generating set.

In some possible embodiments, the blade stall monitoring apparatus further comprises:

the calculation module is used for calculating and obtaining the first time of wind at the current moment from the target wind generating set to the downwind wind generating set predicted to have blade stall;

and the execution module is used for executing a blade stall strategy corresponding to the target wind generating set on the target wind generating set, and executing the blade stall strategy which is the same as the blade stall strategy corresponding to the target wind generating set on the downwind wind generating set predicted to have the blade stall before the first time.

In a fifth aspect, an embodiment of the present invention provides a blade stall monitoring device, which includes a processor, a memory, and a computer program stored in the memory and executable on the processor, and when the computer program is executed by the processor, the blade stall monitoring method according to the technical scheme in the first aspect or the blade stall monitoring method according to the technical scheme in the second aspect is implemented.

In a sixth aspect, an embodiment of the present invention provides a computer-readable storage medium, on which a computer program is stored, where the computer program, when executed by a processor, implements the blade stall monitoring method according to the technical solution in the first aspect or implements the blade stall monitoring method according to the technical solution in the second aspect.

The embodiment of the invention provides a method, a device, equipment and a storage medium for monitoring blade stall, which are used for judging whether the blade stall of a wind generating set occurs or not according to the attack angle of one or more sections of the blade of the wind generating set and the stall attack angle critical value corresponding to the one or more sections. Due to the special shape and the special movement mode of the blades of the wind generating set, the angle of attack of the blades of the wind generating set cannot be measured. In the embodiment of the invention, whether the blade stall occurs in the wind generating set is judged by using the attack angle of the section of the blade, the monitoring of the blade stall of the wind generating set can be realized without measuring the attack angle of the whole blade, whether the blade stall occurs in the wind generating set is determined in advance, the damage of the blade caused by the stall can be avoided, and the operation reliability of the wind generating set is improved.

Drawings

The present invention may be better understood from the following description of specific embodiments of the invention taken in conjunction with the accompanying drawings, in which like or similar reference numerals identify like or similar features.

FIG. 1 is a flow chart of a method of blade stall monitoring in an embodiment of the present invention;

FIG. 2 is a schematic view of an angle of attack of a section of a blade according to an embodiment of the invention;

FIG. 3 is a flow chart of a method of blade stall monitoring in another embodiment of the present invention;

FIG. 4 is a flow chart of another method of blade stall monitoring in an embodiment of the present invention;

FIG. 5 is a schematic view of a wind turbine cluster according to an embodiment of the present invention;

FIG. 6 is a flow chart of another method of blade stall monitoring in accordance with another embodiment of the present invention;

FIG. 7 is a schematic view of a blade stall monitoring apparatus according to an embodiment of the present invention;

FIG. 8 is a schematic view of a blade stall monitoring apparatus according to another embodiment of the present invention;

FIG. 9 is a schematic view of another blade stall monitoring apparatus in accordance with an embodiment of the present invention;

FIG. 10 is a schematic view of another blade stall monitoring apparatus according to another embodiment of the present invention;

FIG. 11 is a schematic view of a blade stall monitoring apparatus according to an embodiment of the present invention.

Detailed Description

Features and exemplary embodiments of various aspects of the present invention will be described in detail below. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the present invention. The present invention is in no way limited to any specific configuration and algorithm set forth below, but rather covers any modification, replacement or improvement of elements, components or algorithms without departing from the spirit of the invention. In the drawings and the following description, well-known structures and techniques are not shown in order to avoid unnecessarily obscuring the present invention.

The embodiment of the invention provides a method, a device, equipment and a storage medium for monitoring blade stall, which can be applied to a stall monitoring scene of a wind generating set. The phenomenon of blade stall may occur in the operation process of the wind generating set, and the motion mode of the blades of the wind generating set is nonlinear displacement motion, so that the attack angle of the blades is difficult to measure. According to the embodiment of the invention, whether the blade stall occurs in the wind generating set is judged by utilizing the attack angle of at least one section of the blade of the wind generating set, so that the monitoring on the blade stall of the wind generating set is realized.

FIG. 1 is a flow chart of a method of blade stall monitoring in an embodiment of the present invention. The blade stall monitoring method can be applied to a single wind generating set. As shown in FIG. 1, the blade stall monitoring method may include steps S101 to S103.

In step S101, an angle of attack of one or more sections of a blade of a wind turbine is measured.

The angle of attack is the angle between the airfoil chord line and the direction of the airflow. The angle of attack of the cross section is the angle between the chord line of the cross section and the direction of the airflow. FIG. 2 is a schematic view of an angle of attack of a section of a blade according to an embodiment of the invention. As shown in fig. 2, the section is a cross section of the blade, and the angle α between the chord line of the cross section and the direction of the airflow is the angle of attack.

In the embodiment of the invention, as the blade consists of a plurality of wing profiles with different thicknesses and chord lengths, the calculation amount of all the sections of the blade is large, one section can be selected, and the attack angle of the section can be calculated. More than two sections can be selected to measure and calculate the attack angle of each section. The different cross-sections have different distances to the blade root. It should be noted that the cross section of the blade may vary due to various factors, for example, in the case of icing the blade, the angle of attack of the cross section of the blade needs to be calculated by considering the influence of the ice type on the angle of attack at the cross section of the blade.

The angle of attack of the cross section may be measured directly by using an external angle of attack sensor, or may be measured and calculated by using relevant parameters of the blade, such as environmental parameters and blade operating parameters, without limitation.

In step S102, a stall angle of attack threshold corresponding to the cross section is determined according to the aerodynamic parameters of the cross section.

Aerodynamic parameters may affect the lift, drag, and the magnitude and direction of various forces experienced by the blade during operation. The stall angle of attack threshold for a section may be determined based on the aerodynamic parameters of the section. The stall angle of attack threshold is a threshold value of angle of attack that defines whether or not stall has occurred. And if the attack angle of the section is larger than the stalling attack angle critical value corresponding to the section, the wind generating set is considered to have the blade stalling phenomenon. And if the attack angle of the section is smaller than or equal to the stalling attack angle critical value corresponding to the section, the wind generating set is considered not to have the blade stalling phenomenon.

In step S103, if the angle of attack of at least one section is greater than the stall angle of attack critical value corresponding to at least one section, it is determined that the wind turbine generator system has blade stall.

If the measured angle of attack of one section is in step S101, it is determined that the wind turbine generator system has blade stall if the angle of attack of the one section is greater than the stall angle of attack critical value corresponding to the one section. If the attack angles of more than two sections are measured in the step S101, a corresponding stall attack angle critical value can be obtained for each section, and if the attack angle of at least one section is greater than the stall attack angle critical value corresponding to the section, it is determined that the blade stall occurs in the wind generating set.

And if the obtained attack angles of all the sections are smaller than or equal to the stalling attack angle critical values corresponding to the sections, judging that the wind generating set does not have blade stalling.

In the embodiment of the invention, whether the blade of the wind generating set stalls is judged according to the attack angle of one or more sections of the blade of the wind generating set and the stall attack angle critical value corresponding to the one or more sections. Due to the special shape and the special movement mode of the blades of the wind generating set, the angle of attack of the blades of the wind generating set cannot be measured. In the embodiment of the invention, whether the blade stall occurs in the wind generating set is judged by using the attack angle of the section of the blade, the monitoring of the blade stall of the wind generating set can be realized without measuring the attack angle of the whole blade, whether the blade stall occurs in the wind generating set is determined in advance, the damage of the blade caused by the stall can be avoided, and the operation reliability of the wind generating set is improved. In addition, in the embodiment of the invention, the monitoring and the protection of the blade of the wind generating set are realized through the self-owned parts of the wind generating set without adding an accessory structure.

FIG. 3 is a flow chart of a method of blade stall monitoring in another embodiment of the present invention. Fig. 3 differs from fig. 1 in that step S101 in fig. 1 may be subdivided into step S1011 in fig. 3, step S103 in fig. 1 may be subdivided into step S1031 in fig. 3, and the blade stall monitoring method shown in fig. 3 may further include step S104.

In step S1011, for a cross section, an environmental parameter, a blade operating parameter, and an axial guidance factor are obtained, and an angle of attack of the cross section is calculated according to the environmental parameter, the blade operating parameter, and the axial guidance factor.

The environmental parameter is used for representing the environmental condition of the wind generating set, for example, the environmental parameter includes wind speed. In some examples, in addition to including wind speed, the environmental parameters may include one or more of: temperature, air density, liquid water content, weather factors. The weather factors can include rain, fog, frost, wind, snow and other weather conditions. Other environmental parameters that can assist in calculating the angle of attack of a cross-section are within the scope of the present invention and are not limited thereto.

In some examples, calibration, sonic or laser measurement, etc. may be used to measure the precise wind speed at each point on the blade surface, thereby improving the accuracy of the wind speed and thus the angle of attack of the cross-section being measured.

The blade operation parameters are used for characterizing blade conditions in an operation process, and may specifically include structural parameters, state parameters, and the like, which are not limited herein. In some examples, the blade operational parameters may include a wind direction angle, a distance between the cross section and a center of a hub of the wind turbine, an impeller speed of the wind turbine, an inherent twist angle value of the cross section, a pitch angle of the blade, and an amount of torsional deformation of the blade. Alternatively, the blade operational parameters may include a wind direction angle, a distance between the cross section and a center of a hub of the wind turbine, an impeller rotation speed of the wind turbine, an inherent twist angle value of the cross section, a pitch angle of the blade, a torsional deformation amount of the blade, a tip loss of the blade, and the like. And if the ratio of the distance between the section and the root of the blade to the length of the blade is out of the loss neglected ratio range, the tip loss of the blade needs to be considered. For example, if the ratio of the loss neglected ratio is [0, 80% ], the tip loss of the blade needs to be considered if the ratio of the distance between the cross section and the root of the blade to the length of the blade is greater than 80%.

The torsional deformation of the blade can be directly measured or a more accurate calculation method of the torsional deformation is adopted, so that the accuracy of the torsional deformation is improved, and the accuracy of the measured and calculated attack angle of the section is improved.

The axial induction factor is used for adjusting the accuracy of the angle of attack of the cross section obtained by measurement and calculation. The axial induction factor may be preset empirically, or may be obtained by performing iterative real-time calculation using a nonlinear equation system, which is not limited herein. For example, the axial induction factor can be preset to 1/3.

For convenience of explanation, the following description will be given with reference to an example. The angle of attack α of the blade cross section can be calculated according to the following equation (1), or calculated according to equations (2) and (3), where equations (2) and (3) and equation (1) can be mutually converted:

wherein gamma is a wind direction angle, namely an included angle between a wind speed direction and the normal direction of a rotating plane; v _wind In terms of wind speed, a is an axial induction factor, n is the impeller rotation speed of the wind turbine generator system, twist angle is an inherent twist angle value of a cross section, PitchAngle is a pitch angle of a blade, and AeroTwist is a torsional deformation amount of the blade.

In step S1031, if the angle of attack of at least one section is greater than the stall angle of attack critical value corresponding to at least one section, and the angle of attack of at least one section satisfies the N-stage stall condition, it is determined that the wind turbine generator system stalls at the N-stage blade.

Wherein N is a positive integer. Different levels of blade stall may be divided for different degrees of blade stall. Different levels of blade stall satisfy different levels of stall conditions. That is, it is determined whether the wind turbine is experiencing N-stage blade stall by determining whether the angle of attack of a section greater than the stall angle of attack threshold satisfies the N-stage stall condition. Wherein a larger value of N indicates a higher severity of blade stall.

In some embodiments, the stall conditions may be divided into primary, secondary, and tertiary stall conditions.

N-1, the primary stall conditions include: the angle of attack of the cross-section is greater than the first angle of attack threshold, and a duration of the angle of attack of the cross-section being greater than the first angle of attack threshold exceeds a first duration threshold.

The first angle of attack threshold and the first duration threshold may be set according to a working scenario and a working requirement, which is not limited herein. For example, the first duration threshold is 30 seconds. It should be noted that the first angle of attack threshold is greater than the stall angle of attack threshold for the section. Each section has a respective first angle of attack threshold, and the first angle of attack threshold for different sections may differ from the stall angle of attack threshold for the section. For example, the ratio of the distance between the blade root of the section a and the blade to the length of the blade is 80%, and the ratio of the distance between the blade root of the section B and the blade to the length of the blade is 50%. The stall angle of attack threshold for section a is StallA and the stall angle of attack threshold for section B is StallB. The first angle of attack threshold corresponding to section a is StallA +2 °, and the first angle of attack threshold corresponding to section B is StallB +4 °.

N-2, the secondary stall conditions include: the attack angle of the cross section is larger than the first attack angle threshold and smaller than or equal to the second attack angle threshold, and the duration of the attack angle of the cross section, which is larger than the first attack angle threshold and smaller than or equal to the second attack angle threshold, exceeds the second duration threshold.

The second attack angle threshold and the second duration threshold may be set according to a working scenario and a working requirement, and are not limited herein. It should be noted that the second angle of attack threshold is greater than the first angle of attack threshold. The second duration threshold is greater than the first duration threshold. For example, as in the above example, the stall angle of attack threshold for section A is StallA. The first angle of attack threshold for section a is StallA + 2. The first duration threshold is 30 seconds. The second threshold angle of attack for section a may be StallA + 4. The second time period threshold may be 10 minutes.

N-3, the three-stage stall condition includes: the angle of attack of the cross-section is greater than a second angle of attack threshold, and a duration of time that the angle of attack of the cross-section is greater than the second angle of attack threshold is greater than a second duration threshold. Alternatively, the three stage stall conditions include: the angle of attack of the cross-section is greater than the third angle of attack threshold, and the duration of the angle of attack of the cross-section being greater than the third angle of attack threshold exceeds the third duration threshold.

The third attack angle threshold and the third duration threshold may be set according to a working scenario and a working requirement, and are not limited herein. It should be noted that the third attack angle threshold is greater than the second attack angle threshold. The third duration threshold is less than the second duration threshold. For example, as in the above example, the stall angle of attack threshold for section A is StallA. The second attack angle threshold for section a may be StallA +4 °. The second time period threshold may be 10 minutes. The third threshold angle of attack for section a may be StallA + 10. The third duration threshold may be 10 seconds.

Other levels of stall conditions may also be provided, and are not limited herein.

In step S104, an N-stage blade stall strategy corresponding to the N-stage blade stall is executed to prompt the wind generating set of the wind generating set for the blade stall or to control the wind generating set to adjust the operation state such that the angle of attack of the at least one section is reduced.

The blade stall strategy of the corresponding level may be set in advance for different levels of blade stall. By making at least one section at a lower angle of attack is meant making at least one section at an angle of attack greater than the stall angle of attack threshold.

In some embodiments, in the case that the blade stall is the first-stage blade stall, executing a first-stage blade stall strategy corresponding to the first-stage blade stall, and sending early warning information to a central controller corresponding to the wind generating set. Namely, the first-stage blade stall strategy comprises the step of sending early warning information to a central controller corresponding to the wind generating set. The warning information may be, but is not limited to, sound information, light information, image information, and the like. And the data that the section attack angle meets the first-stage stall condition can be used as the operation data of the wind generating set to be stored.

And under the condition that the blade stall is the second-stage blade stall, executing a second-stage blade stall strategy corresponding to the second-stage blade stall, and sending a first control instruction to a stall regulation structure of the wind generating set. That is, the secondary blade stall strategy includes sending a first control command to a stall regulation structure of the wind turbine generator set. The first control instruction is for instructing the stall regulation structure to adjust the wind turbine generator set to reduce the angle of attack of the at least one section.

And under the condition that the blade stall is the three-stage blade stall, executing a three-stage blade stall strategy corresponding to the three-stage blade stall, and sending a shutdown instruction to the wind generating set. That is, the three-stage blade stall strategy includes sending a shutdown command to the wind turbine generator set. The shutdown command is used for indicating the wind generating set to be shut down.

It is worth mentioning that in this embodiment, the ratio of the distance of the at least one section from the root of the blade to the length of the blade is higher than the stall withstand length ratio threshold. The distance of the section from the blade root to the length of the blade is higher than the stall bearing length ratio threshold value, and the section is considered to be close to the blade tip. And the distance of the section from the blade root to the length of the blade is lower than or equal to a stall bearing length ratio threshold value, and the section is considered to be close to the blade root. The stall tolerance length ratio threshold may be set according to a working scenario and a working requirement, and is not limited herein. For example, the stall tolerance threshold may be set to 60%, and the section to which the N-stage blade stall strategy in this embodiment is applied is a section in which the ratio of the distance from the blade root to the length of the blade is higher than 60%, for example, a section in which the ratio of the distance from the blade root to the length of the blade is 80%.

In other embodiments, when the blade stall is the first-stage blade stall, a first-stage blade stall strategy corresponding to the first-stage blade stall is executed, and early warning information is sent to a central controller corresponding to the wind generating set. For the related content, reference may be made to the related description of the first-stage blade stall strategy in the above embodiments, and details are not repeated here.

And under the condition that the blade stall is the second-stage blade stall, executing a second-stage blade stall strategy corresponding to the second-stage blade stall, and sending a first control command to a stall regulation structure of the wind generating set. The first control instruction is for instructing the stall regulation structure to adjust the wind park to reduce the angle of attack of the at least one section. For related contents, reference may be made to the related description of the two-stage blade stall strategy in the above embodiments, and details are not repeated herein.

And under the condition that the blade stall is the three-stage blade stall, executing a three-stage blade stall strategy corresponding to the three-stage blade stall, and sending a second control instruction to a stall regulation structure of the wind generating set. The second control instructions are for instructing the stall regulation structure to adjust the wind turbine generator set to reduce the angle of attack of the at least one section. In some examples, the second control command reduces the angle of attack of the at least one section more heavily than the first control command reduces the angle of attack of the at least one section.

It is worth mentioning that in this embodiment, the ratio of the distance of the at least one section from the root of the blade to the length of the blade is lower than or equal to the stall tolerance length ratio threshold. The related contents of the stall tolerance length to the threshold can be referred to the related description in the above embodiments, and are not described herein again. For example, if the stall tolerance threshold may be set to 60%, the section to which the N-stage blade stall strategy in the previous embodiment is applied is a section in which the ratio of the distance from the blade root to the length of the blade is higher than 60%, and the section to which the N-stage blade stall strategy in this embodiment is applied is a section in which the ratio of the distance from the blade root to the length of the blade is lower than or equal to 60%, for example, a section in which the ratio of the distance from the blade root to the length of the blade is 50%.

It should be noted that, the closer the cross section is to the root of the blade, the higher the stall degree that the shape of the cross section can bear, so the specific content of setting the N-stage blade stall strategy can be considered by combining the distance between the cross section and the root of the blade.

In the above embodiment, if the stop instruction is sent to the wind turbine generator system, the stop instruction may instruct the wind turbine generator system to stop, or may instruct the wind turbine generator system to stop for a period of time and then automatically start. For example, the stop instruction instructs the wind turbine generator system to stop, and the wind turbine generator system is automatically started after one hour of stop.

In some examples, the stall regulation structure may include a pitch system of a wind turbine generator set. The first control instruction may also be used to instruct an increase of the pitch angle of the blades of the wind park. The second control instruction may also be for instructing an increase of the pitch angle of the blades of the wind park. The degree of increasing the pitch angle may be set according to the working scene and the working requirement, and is not limited herein. For example, the current pitch angle may be adjusted by 3 ° or 4 °. The first control instruction may, in addition to instructing to increase the pitch angle of the blades of the wind park, instruct to adjust the pitch angle of the blades of the wind park after a period of time to a pitch angle before the increase. For example, the first control instruction instructs that the current value of pitch angle p1 be adjusted by 3 °, and after one hour, the value of pitch angle is adjusted back to p 1.

It should be noted that the degrees by which the first control commands increase the pitch angle for different cross sections may be different. For example, the first control command for the section near the blade tip of the blade increases the pitch angle by a greater number of degrees than the first control command for the section near the blade root of the blade increases the pitch angle by a greater number of degrees. For example, the first control command for the section near the blade tip of the blade increases the pitch angle by 3 degrees, and the first control command for the section near the blade root of the blade increases the pitch angle by 2 degrees.

In other examples, the stall regulation feature includes an aerodynamic profile adjustment device of the blade. The first control command is for instructing a change in the aerodynamic profile of the blade. For example, the aerodynamic profile adjustment device may adjust the section of the blade where stall occurs, or adjust an attachment provided with the blade itself, to change the aerodynamic profile of the blade to avoid blade stall. The second control command may also be used to instruct a change in the aerodynamic profile of the blade.

The embodiment of the invention also provides a blade stall monitoring method applied to the wind turbine group. The wind turbine group includes a plurality of wind turbine generators, and the number of the wind turbine generators in the wind turbine group and the positions of the wind turbine generators are not limited.

FIG. 4 is a flow chart of another method of blade stall monitoring in an embodiment of the present invention. The blade stall monitoring method is applied to a wind turbine generator group. As shown in FIG. 4, the blade stall monitoring method may include step S201 and step S202.

In step S201, a target wind turbine generator set at the outermost periphery of the wind turbine generator set group where blade stall occurs is determined by using the blade stall monitoring method applied to a single wind turbine generator set in the above embodiments.

By using the blade stall monitoring method applied to a single wind generating set in the above embodiments, each outermost wind generating set of the wind generating set group is monitored, and whether a target wind generating set with a stalled blade exists is determined. The target wind generating set is the wind generating set with the blades stalled.

For example, fig. 5 is a schematic diagram of a wind turbine group according to an embodiment of the present invention. As shown in fig. 5, the wind turbine group includes wind turbine generators a1 to a 10. Wherein the outermost located wind park comprises wind parks a1 to A8. The presence of the target wind park may be determined for each of the wind parks a 1-A8 using the blade stall monitoring method applied to a single wind park in the above embodiment.

In step S202, it is predicted whether or not the downwind wind turbine generator system is about to stall the blade, based on the wind angle of the target wind turbine generator system and the wind angle of the downwind turbine generator system.

The downwind wind generating set is a downwind wind generating set of the target wind generating set. The number of the downwind wind turbine generators may be one or more, and is not limited herein. For example, as shown in fig. 5, the downwind genset of wind genset a1 includes wind gensets a9, a10, a5, and a 6.

And predicting whether the blade stall of the downwind wind generating set is about to occur or not according to the wind angle of the target wind generating set and the wind angle of the downwind wind generating set. Since the target wind park has blade stalls, there is a high probability that the target wind park's downwind wind park will also stall. For further judgment, the wind angle of the target wind generating set is compared with the wind angle of the downwind wind generating set, and whether the downwind wind generating set is about to have blade stall or not is determined.

In the embodiment of the invention, the outermost wind generating set in the wind generating set group is monitored by using the blade stall monitoring method applied to a single wind generating set, and if the outermost wind generating set has the wind generating set with the blade stall, the downwind wind generating set of the wind generating set with the blade stall may also have the blade stall. According to the wind angle of the target wind generating set and the wind angle of the downwind wind generating set, whether the downwind wind generating set has blade stall or not can be determined in advance, so that the monitoring and prediction of the blade stall of the wind generating set in the wind generating set group are realized, the damage of the blade caused by the stall can be avoided, and the running reliability of the wind generating set group is improved.

FIG. 6 is a flow chart of another method of blade stall monitoring in another embodiment of the present invention. Fig. 6 differs from fig. 4 in that step S202 in fig. 4 may be refined to step S2021 in fig. 6, and the blade stall monitoring method shown in fig. 6 may further include steps S203 to S205.

In step S2021, if the difference between the wind angle of the target wind turbine generator and the wind angle of the downwind wind turbine generator is within the stall difference threshold range, it is predicted that the wind turbine generator closest to the target wind turbine generator will have blade stall.

The stall difference threshold range may be set according to a work scenario and a work requirement, and is not limited herein. For example, the stall difference threshold range may be [ -8 °, 8 ° ].

If the number of the downwind wind generating sets is one, the difference value between the wind angle of the target wind generating set and the wind angle of the downwind wind generating set is within the stall difference value threshold range, and therefore the fact that the wind generating set closest to the target wind generating set in the downwind wind generating sets is about to have blade stall can be predicted.

If the number of the downwind wind generating sets is multiple, the difference value of the wind angle of the target wind generating set and the wind angle of at least one downwind wind generating set in the multiple downwind wind generating sets is within the stall difference value threshold range, and therefore blade stall of the wind generating set closest to the target wind generating set in the downwind wind generating sets can be predicted to happen.

For example, as shown in fig. 5, the wind turbine group is a wind turbine generator set a1, and if the differences between the wind angles of the target wind turbine generator set a1 and the target wind turbine generator set a9 and the wind angle of the target wind turbine generator set a10 are within the stall difference threshold range, among the downwind wind turbine generator sets a9, a10, a5 and a6, where the downwind turbine generator set a9 and the target wind turbine generator set a1 are closest to each other in the downwind direction, it is predicted that the blade stall of the downwind turbine generator set a9 will occur soon.

And if the difference value of the wind angle of the target wind generating set and the wind angle of the downwind wind generating set is out of the stall difference value threshold range, the wind generating set closest to the target wind generating set in the downwind wind generating set is considered not to have the blade stall.

In step S203, a first time for the current time wind to reach the downwind wind park, where the blade stall is predicted to be imminent, from the target wind park is calculated.

The first duration can be calculated according to the wind speed and the distance between the target wind generating set and the downwind wind generating set closest to the target wind generating set. And calculating to obtain the first time according to the first time length and the current time.

In step S204, a blade stall strategy corresponding to the target wind park is executed on the target wind park.

The blade stall strategy can be referred to as the N-stage stall strategy in the above embodiments, and is not described herein again.

In step S205, before the first time, the same blade stall strategy as the corresponding blade stall strategy of the target wind park is performed on the downwind wind park where blade stall is predicted to be imminent.

The blade stall strategy executed for the downwind wind generating set predicted to have the blade stall is the same as the blade stall strategy corresponding to the target wind generating set, and the blade stall strategy which is the same as the blade stall strategy corresponding to the target wind generating set is executed before wind does not reach the downwind wind generating set predicted to have the blade stall, so that the blade stall is avoided in advance, the blades are prevented from being damaged due to stall, and the reliability of the operation of a wind turbine group is further improved.

FIG. 7 is a schematic view of a blade stall monitoring apparatus according to an embodiment of the present invention. The blade stall monitoring device can be applied to a single wind generating set. As shown in FIG. 7, the blade stall monitoring apparatus 300 may include a meter module 301, a determination module 302, and a stall determination module 303.

The measuring and calculating module 301 is used for measuring and calculating the attack angle of one or more sections of the blade of the wind generating set.

The determining module 302 is configured to determine a stall angle of attack critical value corresponding to the cross section according to the aerodynamic parameter of the cross section.

And the stall determination module 303 is configured to determine that the blade stall occurs in the wind turbine generator system if the angle of attack of the at least one section is greater than a stall angle of attack critical value corresponding to the at least one section.

In the embodiment of the invention, whether the blade stall occurs in the wind generating set is judged according to the attack angle of one or more sections of the blade of the wind generating set and the stall attack angle critical value corresponding to the one or more sections. Due to the special shape and the special movement mode of the blades of the wind generating set, the angle of attack of the blades of the wind generating set cannot be measured. In the embodiment of the invention, whether the blade stall occurs in the wind generating set is judged by using the attack angle of the section of the blade, the monitoring of the blade stall of the wind generating set can be realized without measuring the attack angle of the whole blade, whether the blade stall occurs in the wind generating set is determined in advance, the damage of the blade caused by the stall can be avoided, and the operation reliability of the wind generating set is improved.

In some examples, the aforementioned calculation module 301 may be specifically configured to obtain, for a cross section, an environmental parameter, a blade operating parameter, and an axial induction factor, and calculate an angle of attack of the cross section according to the environmental parameter, the blade operating parameter, and the axial induction factor.

In some examples, the blade operational parameters include a wind direction angle, a distance between the cross-section and a center of a hub of the wind turbine generator system, an impeller speed of the wind turbine generator system, an intrinsic twist angle value of the cross-section, a pitch angle of the blade, and an amount of torsional deformation of the blade.

Or the blade operation parameters comprise a wind direction angle, a distance between the section and the center of a hub of the wind generating set, an impeller rotating speed of the wind generating set, an inherent torsion angle value of the section, a pitch angle of the blade, a torsion deformation amount of the blade and a blade tip loss of the blade.

In some examples, the environmental parameter includes wind speed. Alternatively, the environmental parameter comprises wind speed and one or more of: temperature, air density, liquid water content, weather factors.

In some embodiments, the stall determination module 303 may be specifically configured to determine that the wind turbine generator system has N-stage blade stall if the angle of attack of the at least one section is greater than the stall angle of attack threshold value corresponding to the at least one section and the angle of attack of the at least one section satisfies the N-stage stall condition.

Wherein N is a positive integer.

In some examples, where N ═ 1, the primary stall condition includes: the angle of attack of the cross-section is greater than the first angle of attack threshold, and a duration of the angle of attack of the cross-section being greater than the first angle of attack threshold exceeds a first duration threshold. The first angle of attack threshold is greater than a stall angle of attack threshold corresponding to the section.

N-2, the secondary stall conditions include: the angle of attack of the cross-section is greater than the first angle of attack threshold and less than or equal to the second angle of attack threshold, and the duration of the angle of attack of the cross-section being greater than the first angle of attack threshold and less than or equal to the second angle of attack threshold exceeds a second duration threshold. The second attack angle threshold is greater than the first attack angle threshold, and the second duration threshold is greater than the first duration threshold.

N-3, the three-stage stall condition includes: the attack angle of the cross section is larger than a second attack angle threshold, and the duration of the time that the attack angle of the cross section is larger than the second attack angle threshold is larger than a second duration threshold; or the angle of attack of the cross section is greater than the third angle of attack threshold, and the duration for which the angle of attack of the cross section is greater than the third angle of attack threshold exceeds a third duration threshold. The third attack angle threshold is greater than the second attack angle threshold, and the third duration threshold is less than the second duration threshold.

FIG. 8 is a schematic view of a blade stall monitoring apparatus according to another embodiment of the present invention. FIG. 8 differs from FIG. 7 in that the blade stall monitoring apparatus 300 shown in FIG. 8 may also include an executive module 304.

And an execution module 304, configured to execute an N-stage blade stall strategy corresponding to the N-stage blade stall, so as to prompt the wind generating set of the wind turbine to have the blade stall, or so as to control the wind generating set to adjust an operation state, so that an angle of attack of at least one section is reduced.

In some examples, the execution module 304 is specifically configured to:

Wherein the ratio of the distance of the at least one section from the root of the blade to the length of the blade is above a stall withstand length ratio threshold.

In other examples, the execution module 304 is specifically configured to:

Wherein the ratio of the distance of at least one section from the root of the blade to the length of the blade is lower than or equal to a stall bearing length ratio threshold.

In the above embodiments, in some examples, the stall regulation structure comprises a pitch system of the wind park, the first control instructions being for instructing an increase of a pitch angle of the blades of the wind park. In other examples, the stall regulation feature comprises an aerodynamic profile adjustment device of the blade, and the first control instruction is for instructing a change in an aerodynamic profile of the blade.

FIG. 9 is a schematic view of another blade stall monitoring apparatus according to an embodiment of the present invention. The blade stall monitoring apparatus 400 may be applied to a wind turbine group. As shown in FIG. 7, the blade stall monitoring apparatus 400 may include a targeting module 401 and a prediction module 402.

The target determination module 401 is configured to determine a target wind turbine generator set at the outermost periphery of the wind turbine generator set group where blade stall occurs, by using the blade stall monitoring method applied to a single wind turbine generator set in the above embodiments.

The prediction module 402 is configured to predict whether a downwind wind turbine generator set is about to have blade stall according to a wind angle of a target wind turbine generator set and a wind angle of a downwind wind turbine generator set, where the downwind wind turbine generator set is a downwind wind turbine generator set of the target wind turbine generator set.

In the embodiment of the invention, the blade stall monitoring method applied to a single wind generating set is used for monitoring the wind generating set at the outermost periphery in the wind generating set group, and if the wind generating set with the blade stall exists at the outermost periphery, the downwind wind generating set of the wind generating set with the blade stall may also have the blade stall. According to the wind angle of the target wind generating set and the wind angle of the downwind wind generating set, whether the downwind wind generating set can generate blade stall or not can be determined in advance, so that the monitoring and the prediction of the blade stall of the wind generating set in a wind generating set group are realized, the damage of the blades caused by the stall can be avoided, and the operation reliability of the wind generating set group is improved.

In some examples, the prediction module 402 may be specifically configured to predict that a wind turbine generator set closest to the target wind turbine generator set is about to experience blade stall if the difference between the wind angle of the target wind turbine generator set and the wind angle of the downwind wind turbine generator set is within a stall difference threshold range.

FIG. 10 is a schematic view of another embodiment of a blade stall monitoring apparatus in accordance with the present invention. FIG. 10 differs from FIG. 9 in that the blade stall monitoring apparatus 400 shown in FIG. 10 may also include a calculation module and an execution module.

A calculation module 403, configured to calculate a first time when wind reaches a downwind wind turbine generator set predicted to have blade stall at the present moment from a target wind turbine generator set;

an executing module 404, configured to execute a blade stall strategy corresponding to the target wind generating set for the target wind generating set, and execute a blade stall strategy, which is the same as the blade stall strategy corresponding to the target wind generating set, for the downwind wind generating set predicted to have the blade stall imminent before the first time.

FIG. 11 is a schematic view of a blade stall monitoring apparatus according to an embodiment of the present invention. As shown in FIG. 11, the blade stall monitoring apparatus 500 includes a memory 501, a processor 502, and a computer program stored on the memory 501 and executable on the processor 502.

In one example, the processor 502 described above may include a Central Processing Unit (CPU), or an Application Specific Integrated Circuit (ASIC), or may be configured to implement one or more integrated circuits of embodiments of the present application.

Memory 501 may include a mass storage for data or instructions. By way of example, and not limitation, memory 501 may include an HDD, floppy disk drive, flash memory, optical disk, magneto-optical disk, magnetic tape, or Universal Serial Bus (USB) drive, or a combination of two or more of these. Memory 501 may include removable or non-removable (or fixed) media, where appropriate. The memory 501 may, where appropriate, open the interior or exterior of the blade stall monitoring device 500 at a terminal hot spot. In a particular embodiment, the memory 501 is a non-volatile solid-state memory. In certain embodiments, memory 501 comprises Read Only Memory (ROM). Where appropriate, the ROM may be mask-programmed ROM, Programmable ROM (PROM), Erasable PROM (EPROM), Electrically Erasable PROM (EEPROM), electrically rewritable ROM (EAROM), or flash memory or a combination of two or more of these.

The processor 502 runs a computer program corresponding to the executable program code by reading the executable program code stored in the memory 501 for implementing the blade stall monitoring method applied to a single wind turbine generator set or the blade stall monitoring method applied to a group of wind turbines in the above-described embodiments.

In one example, the blade stall monitoring device 500 may also include a communication interface 503 and a bus 504. As shown in fig. 11, the memory 501, the processor 502, and the communication interface 503 are connected to each other via a bus 504, and perform communication with each other.

The communication interface 503 is mainly used for implementing communication between modules, apparatuses, units and/or devices in the embodiments of the present application. Input devices and/or output devices may also be accessed through communication interface 503.

The bus 504 includes hardware, software, or both that couple the components of the blade stall monitoring apparatus 500 to one another. By way of example, and not limitation, the bus 504 may include an Accelerated Graphics Port (AGP) or other graphics bus, an Enhanced Industry Standard Architecture (EISA) bus, a Front Side Bus (FSB), a Hyper Transport (HT) interconnect, an Industry Standard Architecture (ISA) bus, an infiniband interconnect, a Low Pin Count (LPC) bus, a memory bus, a Micro Channel Architecture (MCA) bus, a Peripheral Component Interconnect (PCI) bus, a PCI-Express (PCI-X) bus, a Serial Advanced Technology Attachment (SATA) bus, a video electronics standards association local (VLB) bus, or other suitable bus, or a combination of two or more of these. Bus 504 may include one or more buses, where appropriate. Although specific buses are described and shown in the embodiments of the application, any suitable buses or interconnects are contemplated by the application.

An embodiment of the present application further provides a computer-readable storage medium, on which a computer program is stored, which, when being executed by a processor, can implement the blade stall monitoring method applied to a single wind turbine generator system or the blade stall monitoring method applied to a wind turbine generator system group in the above embodiments.

It should be clear that the embodiments in this specification are described in a progressive manner, and the same or similar parts between the embodiments are referred to each other, and each embodiment focuses on the differences from the other embodiments. For apparatus embodiments, service device embodiments, and computer-readable storage medium embodiments, reference may be made to the description of the method embodiments for relevant points. The present invention is not limited to the specific steps and structures described above and shown in the drawings. Those skilled in the art may make various changes, modifications and additions or change the order between the steps after appreciating the spirit of the invention. Also, a detailed description of known process techniques is omitted herein for the sake of brevity.

It should be understood by those skilled in the art that the above embodiments are illustrative and not restrictive. Different features which are present in different embodiments may be combined to advantage. Other variations to the disclosed embodiments can be understood and effected by those skilled in the art upon studying the drawings, the specification, and the claims. In the claims, the term "comprising" does not exclude other means or steps; the indefinite article "a" does not exclude a plurality; the terms "first" and "second" are used to denote a name and not to denote any particular order. Any reference signs in the claims shall not be construed as limiting the scope. The functions of the parts appearing in the claims may be implemented by one single hardware or software module. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage.

Claims

1. A method of blade stall monitoring, comprising:

measuring the attack angle of one or more sections of the blade of the wind generating set, wherein the attack angle of the sections is related to the inherent torsion angle value of the sections and the distance between the sections and the center of the hub of the wind generating set;

determining a stall angle of attack critical value corresponding to the section according to the pneumatic parameters of the section;

and if the attack angle of at least one section is larger than the stall attack angle critical value corresponding to the at least one section, determining that the blade stall occurs in the wind generating set.

2. The method of claim 1, wherein said estimating an angle of attack of one or more sections of a blade of a wind park, comprises:

and aiming at one section, acquiring an environmental parameter, a blade operating parameter and an axial induction factor, and calculating to obtain the attack angle of the section according to the environmental parameter, the blade operating parameter and the axial induction factor.

3. The method of claim 2, wherein the blade operational parameters include a wind direction angle, a distance between the cross-section and a center of a hub of the wind park, an impeller speed of the wind park, an intrinsic pitch value of the cross-section, a pitch angle of the blade, and an amount of torsional deformation of the blade;

4. The method of claim 2, wherein the environmental parameter comprises wind speed, or wherein the environmental parameter comprises wind speed and one or more of:

temperature, air density, liquid water content, weather factors.

5. The method according to claim 1, wherein the determining that the wind turbine generator system has a blade stall if the angle of attack of at least one of the sections is greater than a stall angle of attack threshold value corresponding to the at least one of the sections comprises:

if the angle of attack of at least one section is larger than the stall angle of attack critical value corresponding to at least one section, and the angle of attack of at least one section meets the N-stage stall condition, judging that the wind generating set has N-stage blade stall,

wherein N is a positive integer.

6. The method according to claim 5, further comprising, after determining that a blade stall of the wind turbine has occurred:

executing an N-stage blade stall strategy corresponding to the N-stage blade stall to prompt the wind generating set of blade stall or to control the wind generating set to adjust an operating state so that the angle of attack of the at least one section is reduced.

7. The method of claim 5,

n =1, the primary stall condition includes: the attack angle of a section is larger than a first attack angle threshold value, the duration of the time that the attack angle of the section is larger than the first attack angle threshold value exceeds a first duration threshold value, and the first attack angle threshold value is larger than a stall attack angle critical value corresponding to the section;

n =2, the secondary stall conditions include: the attack angle of the cross section is greater than the first attack angle threshold and less than or equal to a second attack angle threshold, the duration of the attack angle of the cross section being greater than the first attack angle threshold and less than or equal to the second attack angle threshold exceeds a second duration threshold, the second attack angle threshold is greater than the first attack angle threshold, and the second duration threshold is greater than the first duration threshold;

n =3, the three stage stall condition includes: the angle of attack of the cross section is greater than the second angle of attack threshold, and the duration that the angle of attack of the cross section is greater than the second angle of attack threshold is greater than the second duration threshold; or the attack angle of the cross section is greater than a third attack angle threshold, the duration of the attack angle of the cross section being greater than the third attack angle threshold exceeds a third duration threshold, the third attack angle threshold is greater than the second attack angle threshold, and the third duration threshold is less than the second duration threshold.

8. The method according to claim 7, further comprising, after determining that a blade stall of the wind turbine has occurred:

when the blade stall is a secondary blade stall, executing a secondary blade stall strategy corresponding to the secondary blade stall, and sending a first control instruction to a stall control structure of the wind generating set, wherein the first control instruction is used for instructing the stall control structure to adjust the wind generating set so as to reduce the attack angle of the at least one section;

and under the condition that the blade stall is a three-stage blade stall, executing a three-stage blade stall strategy corresponding to the three-stage blade stall, and sending a shutdown instruction to the wind generating set, wherein the shutdown instruction is used for instructing the wind generating set to shut down.

9. A method according to claim 8, wherein the ratio of the distance of said at least one said section from the root of the blade to the length of the blade is above a stall withstand length ratio threshold.

10. The method of claim 7, further comprising, after determining that blade stall of the wind turbine has occurred,:

under the condition that the blade stall is first-stage blade stall, executing a first-stage blade stall strategy corresponding to the first-stage blade stall, and sending early warning information to a central controller corresponding to the wind generating set;

and under the condition that the blade stall is three-stage blade stall, executing a three-stage blade stall strategy corresponding to the three-stage blade stall, and sending a second control instruction to a stall regulation and control structure of the wind generating set, wherein the second control instruction is used for instructing the stall regulation and control structure to adjust the wind generating set so as to reduce the attack angle of the at least one section.

11. A method according to claim 10, wherein the ratio of the distance of said at least one said section from the root of said blade to the length of said blade is below or equal to a stall bearing length ratio threshold.

12. The method of claim 8 or 10,

the stall regulation structure comprises a pitch control system of the wind generating set, and the first control instruction is used for instructing to increase the pitch angle of the blades of the wind generating set;

and/or the stall regulation structure comprises an aerodynamic profile adjustment device of the blade, and the first control instruction is used for instructing to change the aerodynamic profile of the blade.

13. A method for monitoring the stall of a blade, characterized in that it is applied to a wind turbine group, said wind turbine group comprising a plurality of wind turbine generators,

the blade stall monitoring method comprises the following steps:

determining a target wind park, at the outermost periphery of the wind park, at which blade stall occurs, using a blade stall monitoring method according to any of claims 1 to 12;

and predicting whether the downwind wind generating set is about to have blade stall or not according to the windward angle of the target wind generating set and the windward angle of the downwind wind generating set, wherein the downwind wind generating set is the downwind wind generating set of the target wind generating set.

14. The method of claim 13, wherein predicting whether a downwind wind park is about to experience blade stall based on a wind angle of the target wind park and a wind angle of the downwind wind park comprises:

and if the difference value between the wind angle of the target wind generating set and the wind angle of the downwind wind generating set is within the stall difference value threshold range, predicting that the wind generating set closest to the target wind generating set in the downwind wind generating set is about to have blade stall.

15. The method of claim 14, further comprising:

calculating the first time for the wind at the current moment to reach the downwind wind generating set predicted to have blade stall;

executing a blade stall strategy corresponding to the target wind generating set on the target wind generating set;

before the first time, executing a blade stall strategy identical to a blade stall strategy corresponding to the target wind park on the downwind wind park predicted to have an imminent blade stall.

16. A blade stall monitoring apparatus, comprising:

the measuring and calculating module is used for measuring and calculating the attack angle of one or more sections of the blade of the wind generating set, wherein the attack angle of the section is related to the inherent torsion angle value of the section and the distance between the section and the center of the hub of the wind generating set;

the determining module is used for determining a stall attack angle critical value corresponding to the section according to the pneumatic parameters of the section;

and the stall judging module is used for judging that the wind generating set has the blade stall if the attack angle of at least one section is larger than the stall attack angle critical value corresponding to the at least one section.

17. The apparatus of claim 16, wherein the blade stall comprises an N-stage blade stall, the apparatus further comprising:

and the execution module is used for executing an N-stage blade stall strategy corresponding to the N-stage blade stall so as to prompt the wind generating set to have blade stall or control the wind generating set to adjust the operation state, so that the attack angle of at least one section is reduced.

18. A blade stall monitoring apparatus, comprising:

a target determination module for determining a target wind park for occurrence of blade stall at an outermost periphery of the wind park, using a blade stall monitoring method according to any of claims 1 to 12;

and the prediction module is used for predicting whether the downwind wind generating set is about to have blade stall or not according to the wind angle of the target wind generating set and the wind angle of the downwind wind generating set, and the downwind wind generating set is the downwind wind generating set of the target wind generating set.

19. The apparatus of claim 18, further comprising:

the calculation module is used for calculating the first time when the wind at the current moment reaches the downwind wind generating set predicted to have blade stall;

and the execution module is used for executing a blade stall strategy corresponding to the target wind generating set on the target wind generating set, and executing the same blade stall strategy as the blade stall strategy corresponding to the target wind generating set on the downwind wind generating set predicted to have the blade stall at the beginning of the first time.

20. A blade stall monitoring apparatus comprising a processor, a memory and a computer program stored on and executable on the memory, the computer program, when executed by the processor, implementing a blade stall monitoring method as claimed in any one of claims 1 to 12 or implementing a blade stall monitoring method as claimed in any one of claims 13 to 15.

21. A computer-readable storage medium, characterized in that a computer program is stored on the computer-readable storage medium, which computer program, when being executed by a processor, is adapted to carry out a method of blade stall monitoring according to any one of the claims 1 to 12 or is adapted to carry out a method of blade stall monitoring according to any one of the claims 13 to 15.