Wind turbine generator stall identification method, identification system, protection method and protection system

Abstract

The embodiment of the invention provides a wind turbine generator stall identification method, identification system, protection method and protection system. The identification method comprises the following steps: acquiring a design power curve, design air density, current wind speed, current air density and current generation power of a wind turbine generator; according to the designed air density, the current wind speed and the current air density, the current wind speed is converted into an identification wind speed; setting a wind speed offset and a wind speed threshold based on the design power curve, and determining a boundary power curve; and when the current generation power is smaller than the boundary power under the corresponding recognition wind speed and the duration is larger than a preset time threshold value, it is judged that the wind turbine generator set is in a stall state. According to the embodiment of the invention, whether the wind turbine generator set is in the stall state or not is more accurately judged by integrating multiple factors, the misrecognition probability is reduced, the stall state of the wind turbine generator set is efficiently and reliably recognized under the condition of not increasing a sensor, and the method can be widely applied to in-service or newly-built wind turbine generator sets.

Description

Technical Field

[0001] The embodiments of the present disclosure belong to the technical field of wind turbine stall identification and protection, and specifically relate to a wind turbine stall identification method, an identification system, and a protection method and a protection system. Background Art

[0002] During operation, wind turbines can easily stall due to certain factors (such as low air density and blade ice). This causes the blades to become aerodynamically unstable and experience significantly greater forces than in normal operation. Prolonged operation in a stalled state can lead to blade failure and fracture, impacting turbine safety. When blades stall, the turbine's operating state manifests itself as rotor speed and power failing to keep pace with wind speed changes, remaining at low speed and power, impacting the turbine's power generation.

[0003] Patent CN115478993A uses whether the blade angle of attack exceeds the critical angle of attack as a criterion. However, this method is limited to situations where the critical angle of attack is known and the blade angle of attack can be accurately calculated. When wind turbine blades are long and the wind speed distribution varies significantly across the rotor's swept surface, it's impossible to accurately determine the wind speed at the blade cross section, making blade angle of attack calculation more difficult.

[0004] Patent CN115929565A proposes installing air pressure sensors on the blades to determine stall based on the measured blade air pressure. This method requires pre-installation of sensors on the blades and pre-determined blade design parameters, making it impractical for wind turbines already in operation.

[0005] In summary, existing stall identification methods are either difficult to obtain and calculate data, or require the installation of additional sensors for online identification, and the demand for sensors is large. These methods are difficult to implement and cannot be widely applied to existing or newly built wind turbines. Summary of the Invention

[0006] The embodiments of the present disclosure aim to solve at least one of the technical problems existing in the prior art, and provide a wind turbine stall identification method, an identification system, and a protection method and a protection system.

[0007] One aspect of the present disclosure provides a method for identifying stall of a wind turbine generator set.

[0008] Other methods include:

[0009] Obtaining a design power curve, design air density, current wind speed, current air density, and current generated power of a wind turbine; wherein the design power curve represents the design power at each wind speed;

[0010] converting the current wind speed into an identified wind speed according to the design air density, the current wind speed, and the current air density;

[0011] Setting a wind speed offset and a wind speed threshold based on the design power curve to determine a boundary power curve; wherein the boundary power curve represents the boundary power at each identified wind speed;

[0012] When the current generated power is less than the boundary power at the corresponding identified wind speed and the duration is greater than a preset time threshold, it is determined that the wind turbine is in a stall state.

[0013] Furthermore, the identified wind speed is converted by the following formula:

[0014]

[0015] Where, v e To identify the wind speed, v m is the current wind speed, ρ m is the current air density, ρ ref is the design air density, p m is the current air pressure, p ref is the design air pressure, t m is the current temperature.

[0016] Furthermore, the boundary power curve is determined by the following formula:

[0017]

[0018] Where, P t is the boundary power, f(·) is the power calculation function, v is the wind speed, v b is the wind speed bias, v t is the wind speed threshold.

[0019] Furthermore, after determining that the wind turbine is in a stall state, the identification method further includes:

[0020] Get the current temperature of the wind turbine;

[0021] When the current air temperature is less than or equal to 0, it is determined that the blades of the wind turbine generator set are in an ice-covered state.

[0022] Another aspect of the present disclosure provides a wind turbine stall identification system, the identification system comprising:

[0023] An acquisition module is used to obtain a design power curve, a design air density, a current wind speed, a current air density, and a current generated power of a wind turbine; wherein the design power curve represents the design power at each wind speed;

[0024] a conversion module, configured to convert the current wind speed into an identified wind speed according to the design air density, the current wind speed, and the current air density;

[0025] A boundary module is used to set a wind speed offset and a wind speed threshold based on the design power curve to determine a boundary power curve; wherein the boundary power curve represents the boundary power at each identified wind speed;

[0026] The judgment module is used to judge that the wind turbine is in a stall state when the current generated power is less than the boundary power under the corresponding identified wind speed and the duration is greater than a preset time threshold.

[0027] Furthermore, the acquisition module is also used to obtain the current temperature of the wind turbine generator set;

[0028] The judgment module is further configured to judge that the blades of the wind turbine generator set are in an ice-covered state when the current temperature is less than or equal to 0.

[0029] Another aspect of the present disclosure provides a wind turbine stall protection method. Based on the wind turbine stall identification method described above, after determining that the wind turbine is in a stall state, the protection method includes:

[0030] Setting a minimum blade pitch angle of the wind turbine; wherein the minimum blade pitch angle is calculated based on a design pitch angle corresponding to the identified wind speed and an additional pitch angle for stall protection;

[0031] The pitch angles of the wind turbine blades are controlled according to the minimum blade pitch angle, and the control of the wind turbine blades is stopped after a preset protection time period.

[0032] Furthermore, the minimum blade pitch angle is expressed as follows:

[0033]

[0034] Where β is the minimum blade pitch angle, βs is the stall protection additional pitch angle,

[0035] is the design pitch angle calculation function, v e To identify wind speed.

[0036] Another aspect of the present disclosure provides a wind turbine stall protection system, based on the wind turbine stall identification system described above, the protection system comprising:

[0037] a setting module, configured to set a minimum blade pitch angle of the wind turbine after determining that the wind turbine is in a stall state; wherein the minimum blade pitch angle is calculated based on a design pitch angle corresponding to the identified wind speed and an additional pitch angle for stall protection;

[0038] The control module is configured to control the pitch angles of the wind turbine blades according to the minimum blade pitch angle and stop controlling the wind turbine blades after a preset protection time has passed.

[0039] Furthermore, the setting module sets the minimum blade pitch angle by the following formula:

[0040]

[0041] Where β is the minimum blade pitch angle, βs is the stall protection additional pitch angle,

[0042] is the design pitch angle calculation function, v e To identify wind speed.

[0043] The embodiments of the present disclosure provide a wind turbine stall identification method, identification system, protection method, and protection system. By integrating multiple factors, it is possible to more accurately determine whether a wind turbine is in a stall state, thereby reducing the probability of misidentification. Without adding sensors, the stall state of a wind turbine can be efficiently and reliably identified, and the method and system are widely applicable to existing or newly built wind turbines. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 1 is a flow chart of a method for identifying stall of a wind turbine generator system according to an embodiment of the present disclosure;

[0045] Figure 2 This is a schematic diagram of a power curve according to another embodiment of the present disclosure;

[0046] Figure 3 This is a structural diagram of a wind turbine stall identification system according to another embodiment of the present disclosure;

[0047] Figure 4 This is a flow chart of a stall protection method for a wind turbine generator set according to another embodiment of the present disclosure;

[0048] Figure 5 The figure is a schematic structural diagram of a wind turbine stall protection system according to another embodiment of the present disclosure. DETAILED DESCRIPTION

[0049] The following will be combined with the accompanying drawings in the embodiments of the present disclosure to clearly and completely describe the technical solutions in the embodiments of the present disclosure. Obviously, the embodiments described are only part of the embodiments of the present disclosure, not all of the embodiments. Based on the embodiments of the present disclosure, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present disclosure.

[0050] In addition, the described features, structures or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to provide a full understanding of the embodiments of the present disclosure. However, those skilled in the art will appreciate that the technical solutions of the present disclosure can be practiced without one or more of the specific details, or other methods, components, devices, steps, etc. can be adopted. In other cases, well-known methods, devices, implementations or operations are not shown or described in detail to avoid blurring various aspects of the present disclosure.

[0051] The flowcharts shown in the accompanying drawings are for illustrative purposes only and do not necessarily include all contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may be decomposed, while others may be combined or partially combined. Therefore, the actual execution order may vary depending on the actual situation.

[0052] It should be understood that although the terms first, second, third, etc. may be used in this disclosure to describe various components, these components should not be limited by these terms. These terms are used to distinguish one component from another. Thus, the first component discussed below can be referred to as the second component without departing from the teachings of the concepts of this disclosure. As used in this disclosure, the term "and / or" includes any one of the associated listed items and all combinations of one or more of them.

[0053] Those skilled in the art will understand that the drawings are merely schematic diagrams of example embodiments, and the modules or processes in the drawings are not necessarily necessary for implementing the present disclosure, and therefore cannot be used to limit the scope of protection of the present disclosure.

[0054] like Figure 1 As shown, an embodiment of the present disclosure provides a method for identifying stall of a wind turbine generator set, the method comprising:

[0055] Step S11: Obtain the design power curve, design air density, current wind speed, current air density and current generated power of the wind turbine.

[0056] Specifically, the design power curve represents the design power at each wind speed. The design power curve of all wind turbines in service or newly built is obtained, or a power curve under normal power generation status is fitted after filtering historical operating data with additional conditions as the design power curve. Figure 2As shown, the wind turbine operates near the design power curve during normal power generation. When the actual operating state deviates from the power curve beyond a certain range, it can be considered that the wind turbine operation is abnormal. When the wind turbine enters the stall state, the curve composed of the actual power scatter points of the wind turbine, that is, the power curve in the stall state, will be below the design power curve. The calculation function of the design power curve can be expressed as P = f(v), with the input being wind speed v and the output being power P. The stall of the wind turbine is related to wind speed, air temperature, air pressure, power generation, and power restriction status. Obtain the design air density ρ referenced by the design power curve ref , the current wind speed v is measured by several sensors installed on the wind turbine m , temperature t m , air pressure p m , measure the current power generation P m , and the current air density ρ can be calculated by the following formula m :

[0057]

[0058] Among them, p ref The design air pressure is usually the standard atmospheric pressure. The current air density ρ m In addition to being calculated through temperature and air pressure, it can also be measured through an air density sensor.

[0059] Step S12: converting the current wind speed into an identified wind speed according to the design air density, the current wind speed, and the current air density.

[0060] Specifically, according to the design air density ρ obtained in the previous step S1 ref 、Current wind speed v m and the current air density ρ m , the measured current wind speed v m Converted to the reference air density ρ of the design power curve ref The corresponding identification wind speed v e , the specific conversion formula is as follows:

[0061]

[0062] Step S13: setting a wind speed offset and a wind speed threshold based on the design power curve, and determining a boundary power curve.

[0063] Specifically, refer to Figure 2 Based on the design power curve, a boundary power curve is set within a certain range. When the actual current power generation power of the wind turbine exceeds the boundary, it is considered that the turbine has entered a stall state or the stall protection measures need to be activated.

[0064] The boundary power curve is obtained by adding the offset based on the design power curve. Set the wind speed offset v b and wind speed threshold v t , the boundary power curve can be determined by the following formula:

[0065]

[0066] Where, P t is the boundary power, f(·) is the wind speed-power calculation function of the design power curve, and v is the wind speed. e The corresponding boundary power can be expressed as P e .

[0067] Step S14: When the current generated power is less than the boundary power at the corresponding identified wind speed and the duration is greater than a preset time threshold, it is determined that the wind turbine is in a stall state.

[0068] Specifically, when the wind turbine is not in a power-limiting state, when the measured current power generation power P m <P e , which corresponds to the identification of wind speed v e The current power point is located at Figure 2 The power curve is below the boundary shown, and the duration is greater than the pre-set time threshold T s , it is determined that the wind turbine is in a stall state. In addition, when the current temperature t m When ≤0, it can be determined that the blades of the wind turbine are in an ice-covered state.

[0069] The wind speed-power curve described above can also be replaced by a wind speed-rotation speed curve. Simply replace all power-related parameters with rotation speed-related parameters, and the same identification method will achieve the same effect.

[0070] A wind turbine stall identification method according to an embodiment of the present disclosure can more accurately determine whether a wind turbine is in a stall state by integrating multiple factors, thereby reducing the probability of misidentification. It can efficiently and reliably identify the stall state of a wind turbine without adding sensors, and is widely applicable to existing or newly built wind turbines.

[0071] like Figure 3 As shown, another embodiment of the present disclosure provides a wind turbine stall identification system, the identification system comprising:

[0072] An acquisition module 310 is configured to acquire a design power curve, a design air density, a current wind speed, a current air density, and a current generated power of a wind turbine; wherein the design power curve represents the design power at each wind speed;

[0073] a conversion module 320, configured to convert the current wind speed into an identified wind speed according to the design air density, the current wind speed, and the current air density;

[0074] A boundary module 330 is configured to set a wind speed offset and a wind speed threshold based on the design power curve to determine a boundary power curve; wherein the boundary power curve represents the boundary power at each identified wind speed;

[0075] The judgment module 340 is configured to judge that the wind turbine is in a stall state when the current generated power is less than the boundary power at the corresponding identified wind speed and the duration is greater than a preset time threshold.

[0076] Exemplarily, the acquisition module 310 is further configured to acquire the current temperature of the wind turbine generator set; and the judgment module 340 is further configured to judge whether the blades of the wind turbine generator set are in an ice-covered state when the current temperature is less than or equal to 0.

[0077] Specifically, a wind turbine stall identification system according to an embodiment of the present disclosure is used to implement the wind turbine stall identification method described in the above embodiments. The specific implementation process has been described in detail in the above embodiments and will not be repeated here.

[0078] A wind turbine stall identification system according to an embodiment of the present disclosure can more accurately determine whether a wind turbine is in a stall state by integrating multiple factors, reducing the probability of misidentification. It can efficiently and reliably identify the stall state of a wind turbine without adding sensors, and can be widely applicable to existing or newly built wind turbines.

[0079] like Figure 4 As shown, another embodiment of the present disclosure provides a wind turbine stall protection method based on the wind turbine stall identification method described above. After determining that the wind turbine is in a stall state, the protection method includes:

[0080] Step S41: setting the minimum blade pitch angle of the wind turbine.

[0081] Specifically, the minimum blade pitch angle is calculated based on the design pitch angle corresponding to the identified wind speed and the stall protection additional pitch angle, as expressed by the following formula:

[0082]

[0083] Where β is the minimum blade pitch angle, βs is the stall protection additional pitch angle, is the wind speed-pitch angle calculation function in the wind turbine design parameters, v e To identify wind speed.

[0084] Step S42: controlling the pitch angles of the wind turbine blades according to the minimum blade pitch angle, and stopping controlling the wind turbine blades after a preset protection time has elapsed.

[0085] Specifically, when it is determined that the wind turbine is in a stall state, the blades of the wind turbine are controlled to continuously change pitch according to the above-set minimum blade pitch angle β, thereby executing the stall protection. p After that, regardless of whether the pitch change action is completed, the minimum blade pitch angle restriction is canceled and the stall protection is exited. Then, the steps of the wind turbine stall identification method described above are executed again to identify whether the wind turbine is in a stall state and whether stall protection needs to be executed, and the cycle continues.

[0086] A wind turbine stall protection method according to an embodiment of the present disclosure dynamically adjusts the pitch angle of the wind turbine blades according to the wind speed. It can efficiently and reliably perform wind turbine stall protection without adding sensors, and can be widely applicable to existing or newly built wind turbines.

[0087] like Figure 5 As shown, another embodiment of the present disclosure provides a wind turbine stall protection system based on the wind turbine stall identification system described in the above embodiment. The protection system includes:

[0088] a setting module 510 configured to set a minimum blade pitch angle of the wind turbine after the wind turbine stall identification system determines that the wind turbine is in a stall state; wherein the minimum blade pitch angle is calculated based on a design pitch angle corresponding to the identified wind speed and an additional stall protection pitch angle;

[0089] The control module 520 is configured to control the pitch angles of the wind turbine blades according to the minimum blade pitch angle, and stop controlling the wind turbine blades after a preset protection time has elapsed.

[0090] Exemplarily, the setting module 510 sets the minimum blade pitch angle by the following formula:

[0091]

[0092] Where β is the minimum blade pitch angle, βs is the stall protection additional pitch angle, is the design pitch angle calculation function, v e To identify wind speed.

[0093] Specifically, a wind turbine stall protection system according to an embodiment of the present disclosure is used to implement the wind turbine stall protection method described in the above embodiments. The specific implementation process has been described in detail in the above embodiments and will not be repeated here.

[0094] A wind turbine stall protection system according to an embodiment of the present disclosure dynamically adjusts the pitch angle of the wind turbine blades according to wind speed settings, can efficiently and reliably perform wind turbine stall protection without adding sensors, and can be widely applied to existing or newly built wind turbines.

[0095] It is understood that the above embodiments are merely exemplary embodiments for illustrating the principles of the present disclosure, and the present disclosure is not limited thereto. Those skilled in the art may make various modifications and improvements without departing from the spirit and substance of the present disclosure, and such modifications and improvements are also considered to be within the scope of protection of the present disclosure.

Claims

1. A method for identifying stall of a wind turbine, characterized in that: The identification method comprises: Obtaining a design power curve, design air density, current wind speed, current air density, and current generated power of a wind turbine; wherein the design power curve represents the design power at each wind speed; converting the current wind speed into an identified wind speed according to the design air density, the current wind speed, and the current air density; Setting a wind speed offset and a wind speed threshold based on the design power curve to determine a boundary power curve; wherein the boundary power curve represents the boundary power at each identified wind speed; When the current generated power is less than the boundary power at the corresponding identified wind speed and the duration is greater than a preset time threshold, it is determined that the wind turbine is in a stall state.

2. The identification method according to claim 1, characterized in that The identified wind speed is converted by the following formula: Where, v e To identify the wind speed, v m is the current wind speed, ρ m is the current air density, ρ ref is the design air density, p m is the current air pressure, p ref is the design air pressure, t m is the current temperature.

3. The identification method according to claim 1, characterized in that The boundary power curve is determined by the following formula: Where, P t is the boundary power, f(·) is the power calculation function, v is the wind speed, v b is the wind speed bias, v t is the wind speed threshold.

4. The identification method according to any one of claims 1 to 3, characterized in that: After determining that the wind turbine is in a stall state, the identification method further includes: Get the current temperature of the wind turbine; When the current air temperature is less than or equal to 0, it is determined that the blades of the wind turbine generator set are in an ice-covered state.

5. A wind turbine stall identification system, characterized in that: The identification system comprises: An acquisition module is used to obtain a design power curve, a design air density, a current wind speed, a current air density, and a current generated power of a wind turbine; wherein the design power curve represents the design power at each wind speed; a conversion module, configured to convert the current wind speed into an identified wind speed according to the design air density, the current wind speed, and the current air density; A boundary module is used to set a wind speed offset and a wind speed threshold based on the design power curve to determine a boundary power curve; wherein the boundary power curve represents the boundary power at each identified wind speed; The judgment module is used to judge that the wind turbine is in a stall state when the current generated power is less than the boundary power under the corresponding identified wind speed and the duration is greater than a preset time threshold.

6. The identification system according to claim 5, characterized in that The acquisition module is also used to obtain the current temperature of the wind turbine; The judgment module is further configured to judge that the blades of the wind turbine generator set are in an ice-covered state when the current temperature is less than or equal to 0.

7. A wind turbine stall protection method, based on the wind turbine stall identification method according to any one of claims 1 to 4, characterized in that: After determining that the wind turbine generator set is in a stall state, the protection method includes: Setting a minimum blade pitch angle of the wind turbine; wherein the minimum blade pitch angle is calculated based on a design pitch angle corresponding to the identified wind speed and an additional pitch angle for stall protection; The pitch angles of the wind turbine blades are controlled according to the minimum blade pitch angle, and the control of the wind turbine blades is stopped after a preset protection time period.

8. The protection method according to claim 7, characterized in that: The minimum blade pitch angle is expressed as follows: Where β is the minimum blade pitch angle, βs is the stall protection additional pitch angle, is the design pitch angle calculation function, v e To identify wind speed.

9. A wind turbine stall protection system, based on the wind turbine stall identification system according to claim 5 or 6, characterized in that: The protection system comprises: a setting module, configured to set a minimum blade pitch angle of the wind turbine after determining that the wind turbine is in a stall state; wherein the minimum blade pitch angle is calculated based on a design pitch angle corresponding to the identified wind speed and an additional pitch angle for stall protection; The control module is configured to control the pitch angles of the wind turbine blades according to the minimum blade pitch angle and stop controlling the wind turbine blades after a preset protection time has passed.

10. The protection system according to claim 9, characterized in that The setting module sets the minimum blade pitch angle by the following formula: Where β is the minimum blade pitch angle, βs is the stall protection additional pitch angle, is the design pitch angle calculation function, v e To identify wind speed.

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