A wind turbine unified blade runaway fault identification method and system

Abstract

The present invention discloses a method and system for identifying a unified blade runaway fault in a wind turbine generator set, comprising: 1) calculating the expected pitch following error of each blade based on the pitch command of each blade and the current pitch angle of each blade; 2) calculating the derivative of the expected pitch following error of each blade based on the expected pitch following error, and obtaining the pitch following error change rate after filtering; 3) judging whether blade 1, blade 2, and blade 3 have runaway faults at the same time based on the pitch following error change rate, obtaining a unified blade runaway fault flag, and triggering it to be a positive unified blade runaway fault flag or a negative unified blade runaway fault flag; 4) obtaining a unified runaway fault shutdown flag based on the unified blade runaway fault flag, and triggering the wind turbine generator set to enter a unified runaway fault shutdown logic. The present invention can improve fault identification accuracy and reduce fault identification time, and will not mistakenly identify a single blade runaway as a unified blade runaway fault.

Description

Technical Field

[0001] The present invention relates to the technical field of wind turbine generator set control, and in particular to a method, system, storage medium and computing device for identifying a unified blade runaway fault of a wind turbine generator set. Background Art

[0002] Wind turbines are subject to various unavoidable faults throughout their lifecycle. Among them, the unified blade runaway fault of a wind turbine is a type of fault condition that must be considered in IEC design specifications. A unified blade runaway fault occurs when a wind turbine is operating in normal turbulent winds and all three blades lose control simultaneously, running away at either the positive maximum pitch rate or the negative maximum pitch rate. After the control system identifies the unified blade runaway fault, it triggers the safety chain of the pitch system and immediately shuts down the unit. Currently, there is no specific method for identifying unified blade runaway faults, and it can only be identified through the following error of the pitch command. However, to avoid false shutdowns under normal power generation conditions, the threshold for the following error is usually set relatively high. Existing methods cannot quickly identify blade runaway faults and tend to categorize single-blade runaway faults, stuck-blade faults, and unified blade runaway faults as the same type of fault, making it difficult to perform fault-specific shutdown control. Summary of the Invention

[0003] The first purpose of the present invention is to overcome the shortcomings and deficiencies of the prior art and provide a method for identifying a unified blade runaway fault in a wind turbine. By introducing the expected pitch following error and the pitch following error change rate, an effective identification method for the unified blade runaway fault is proposed, which can improve the fault identification accuracy and reduce the fault identification time, and will not mistakenly identify a single blade runaway fault as a unified blade runaway fault.

[0004] A second object of the present invention is to provide a wind turbine generator set unified blade runaway fault identification system.

[0005] A third object of the present invention is to provide a storage medium.

[0006] A fourth object of the present invention is to provide a computing device.

[0007] The first object of the present invention is achieved by the following technical solution: a method for identifying a unified blade runaway fault in a wind turbine generator set, performing the following operations:

[0008] 1) Based on the pitch commands for each blade output by the pitch controller and the current pitch angles of each blade measured by the sensors, the expected following error of each blade is calculated;

[0009] 2) Based on the desired pitch following error obtained in step 1), the derivative of the desired pitch following error of each blade is calculated, and the rate of change of the pitch following error is obtained after filtering;

[0010] 3) Based on the pitch following error change rate obtained in step 2), determine whether blade 1, blade 2, and blade 3 have runaway faults at the same time, obtain a unified blade runaway fault flag, and determine whether the unified blade runaway fault flag is triggered in a positive direction or a negative direction;

[0011] 4) Based on the unified blade runaway fault flag obtained in step 3), a unified runaway fault shutdown flag is obtained, and the wind turbine generator set is triggered to enter the unified runaway fault shutdown logic until the unit is completely shut down.

[0012] Furthermore, in step 1), the pitch command of each blade is subjected to a pitch second-order transfer function operation to obtain a desired pitch angle of each blade; the desired pitch angle of each blade is then subtracted from the current pitch angle measured for the corresponding blade to obtain a desired pitch following error of each blade;

[0013] The second-order transfer function of the pitch control is defined as follows:

[0014]

[0015] In the above formula, H(s) represents the second-order transfer function of pitch; ω n represents the natural frequency of the pitch system; ξ represents the damping ratio of the pitch system; s represents the Laplace variable; e -τs represents the delay link, and the delay time constant is τ; wherein, the natural frequency, damping ratio and delay time constant of the pitch system can be obtained through the step response test of the pitch system;

[0016] The calculation formula of the expected following error of the pitch control is as follows:

[0017]

[0018] In the above formula, represents the expected following error of blade 1; represents the expected following error of blade 2; represents the expected following error of blade 3; Indicates the pitch command of blade 1, which is output by the pitch controller; represents the pitch command of blade 2, which is output by the pitch controller; represents the pitch command of blade 3, which is output by the pitch controller; Indicates the current pitch angle of blade 1, measured by the sensor; Indicates the current pitch angle of blade 2, measured by the sensor; Indicates the current pitch angle of blade 3, measured by the sensor.

[0019] Further, in step 2), the derivative of the desired pitch following error of blade 1 with respect to time is obtained, and the result is filtered to obtain the rate of change of the pitch following error of blade 1; the derivative of the desired pitch following error of blade 2 with respect to time is obtained, and the result is filtered to obtain the rate of change of the pitch following error of blade 2; the derivative of the desired pitch following error of blade 3 with respect to time is obtained, and the result is filtered to obtain the rate of change of the pitch following error of blade 3;

[0020] The calculation formula of the pitch following error change rate is as follows:

[0021]

[0022] In the above formula, represents the rate of change of the pitch following error of blade 1; Pitch following error change rate; represents the rate of change of the pitch following error of blade 3; Filter(·) represents the filter function; represents the expected following error of blade 2; represents the expected following error of blade 3;

[0023] When a wind turbine is operating normally, the rate of change of the pitch following error of each blade is close to zero; when a blade runaway failure occurs, the rate of change of the pitch following error of the three blades will quickly deviate from zero.

[0024] Furthermore, the filter selects a first-order low-pass filter, a second-order low-pass filter or a sliding average filter to remove high-frequency noise signals.

[0025] Further, in step 3), the method for identifying a unified blade runaway fault is as follows: when blades 1, 2, and 3 all run away at the positive maximum pitch rate, the pitch following error change rate of the three blades will deviate from zero and be significantly higher than zero, and this is a positive unified blade runaway fault; when blades 1, 2, and 3 all run away at the negative maximum pitch rate, the pitch following error change rate of the three blades will deviate from zero and be significantly lower than zero, and this is a negative unified blade runaway fault; by setting the upper and lower thresholds, the unified blade runaway fault can be identified;

[0026] The forward unified blade runaway fault flag is defined as follows:

[0027]

[0028] In the above formula, Indicates the positive unified blade runaway fault flag, identifying three blades running away at a positive pitch rate; represents the rate of change of the pitch following error of blade 1; represents the rate of change of the pitch following error of blade 2; represents the rate of change of the pitch following error of blade 3; C H Indicates the upper threshold of the pitch following error change rate; if indicates the following judgment condition; & indicates the logical AND operation; else indicates other conditions;

[0029] The negative unified blade runaway fault flag is defined as follows:

[0030]

[0031] In the above formula, Indicates the negative unified blade runaway fault flag, identifying three blades running away at a negative pitch rate; C L Indicates the lower threshold of the pitch following error change rate.

[0032] Furthermore, in step 4), when the positive unified blade runaway fault flag or the negative unified blade runaway fault flag is triggered, the unified runaway fault shutdown flag is triggered; the unified runaway fault shutdown flag is defined as follows:

[0033]

[0034] In the above formula, Flag is the unified runaway fault shutdown flag; Indicates the forward unified blade runaway fault flag; Indicates the negative unified blade runaway fault flag; or represents the logical OR operation; when it is identified that three blades are uniformly runaway at a positive pitch rate or at a negative pitch rate, the unified runaway fault shutdown flag will be triggered, and the wind turbine will enter the unified runaway fault shutdown logic;

[0035] When the wind turbine enters the unified runaway fault shutdown logic, the pitch rate setting value during the shutdown process is a table lookup value. The pitch rate setting value is obtained by looking up the table according to the current pitch angle. The specific definition is as follows:

[0036]

[0037] In the above formula, Indicates the blade 1 pitch rate setting value for the unified runaway fault shutdown process;

[0038] Indicates the blade 2 pitch rate setting value for the unified runaway fault shutdown process; Indicates the blade 3 pitch rate setting value for the unified runaway fault shutdown process; Lookup_P represents the unified runaway fault shutdown pitch rate lookup table function; Indicates the current pitch angle of blade 1, measured by the sensor; Indicates the current pitch angle of blade 2, measured by the sensor; Indicates the current pitch angle of blade 3, measured by the sensor;

[0039] When the wind turbine enters the unified runaway fault shutdown logic, the generator torque setting value during the shutdown process is a table lookup value. The generator torque setting value is obtained by looking up the table according to the current generator speed. The specific definition is as follows:

[0040]

[0041] In the above formula, Represents the generator torque setting value for the unified runaway fault shutdown process; Lookup_T represents the unified runaway fault shutdown generator torque lookup function; Indicates the current generator speed, measured by the sensor.

[0042] The second object of the present invention is achieved by the following technical solution: a wind turbine unified blade runaway fault identification system, used to implement the above-mentioned wind turbine unified blade runaway fault identification method, comprising:

[0043] The pitch expected following error module calculates the pitch expected following error of each blade based on the pitch command of each blade output by the pitch controller and the current pitch angle of each blade measured by the sensor;

[0044] The pitch following error change rate module calculates the derivative of the pitch expected following error of each blade based on the pitch expected following error obtained by the pitch expected following error module, and obtains the pitch following error change rate after filtering;

[0045] The unified blade runaway fault identification module determines whether blades 1, 2, and 3 have runaway faults at the same time based on the pitch following error change rate obtained by the pitch following error change rate module, and obtains the unified blade runaway fault flag, which triggers a positive unified blade runaway fault flag or a negative unified blade runaway fault flag.

[0046] The unified blade runaway fault shutdown module obtains the unified blade runaway fault flag based on the unified blade runaway fault identification module, and triggers the wind turbine generator set to enter the unified runaway fault shutdown logic until the unit is completely shut down.

[0047] The third object of the present invention is achieved through the following technical solution: a storage medium stores a program, and when the program is executed by a processor, the above-mentioned method for identifying the unified blade runaway fault of the wind turbine generator set is implemented.

[0048] The fourth purpose of the present invention is achieved through the following technical solution: a computing device, comprising a processor and a memory for storing a program executable by the processor, wherein when the processor executes the program stored in the memory, the above-mentioned method for identifying a unified blade runaway fault of a wind turbine is implemented.

[0049] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0050] 1. The present invention obtains the derivative of the expected pitch following error of each blade and, when a fault occurs, utilizes the characteristic that the rate of change of the pitch following error deviates from zero, thereby being able to more quickly identify a unified runaway fault.

[0051] 2. The present invention does not require additional sensors and measuring equipment, can effectively identify the unified blade runaway fault, and will not mistakenly identify other faults as the unified blade runaway fault.

[0052] 3. The present invention can distinguish between a positive pitch rate uniform runaway and a negative pitch rate uniform runaway, thus providing a possibility for fault-based shutdown logic control. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 This is an architecture diagram of the system of the present invention. DETAILED DESCRIPTION

[0054] The present invention will be described in further detail below with reference to the embodiments and drawings, but the embodiments of the present invention are not limited thereto.

[0055] Example 1

[0056] This embodiment discloses a method for identifying a wind turbine blade runaway fault, which includes performing the following operations:

[0057] 1) Based on the pitch commands of each blade output by the pitch controller and the current pitch angle of each blade measured by the sensor, the expected pitch following error of each blade is calculated.

[0058] The specific method is as follows: after the pitch command of each blade is subjected to the pitch second-order transfer function operation, the expected pitch angle of each blade is obtained; then the expected pitch angle of each blade is subtracted from the current pitch angle measured by the corresponding blade to obtain the expected pitch following error of each blade.

[0059] Due to communication delays in the pitch system and inertial lags in the pitch actuator, the measured current pitch angle cannot completely track the blade pitch command. However, by introducing a second-order pitch transfer function, which accounts for the pitch system delays and inertial lags, the desired pitch angle is very close to the measured current pitch angle.

[0060] The second-order transfer function of the pitch control is defined as follows:

[0061]

[0062] In the above formula, H(s) represents the second-order transfer function of pitch; ω n represents the natural frequency of the pitch system; ξ represents the damping ratio of the pitch system; s represents the Laplace variable; e -τs represents the delay link, and the delay time constant is τ. Among them, the natural frequency, damping ratio and delay time constant of the pitch system can be obtained through the step response test of the pitch system.

[0063] The calculation formula of the expected following error of the pitch control is as follows:

[0064]

[0065] In the above formula, represents the expected following error of blade 1; represents the expected following error of blade 2; represents the expected following error of blade 3; H(s) represents the second-order transfer function of the pitch; Indicates the pitch command of blade 1, which is output by the pitch controller; represents the pitch command of blade 2, which is output by the pitch controller; represents the pitch command of blade 3, which is output by the pitch controller; Indicates the current pitch angle of blade 1, measured by the sensor; Indicates the current pitch angle of blade 2, measured by the sensor; Indicates the current pitch angle of blade 3, measured by the sensor.

[0066] 2) Based on the desired pitch following error obtained in step 1), the derivative of the desired pitch following error of each blade is calculated, and the rate of change of the pitch following error is obtained after filtering.

[0067] The specific method is: taking the derivative of the expected pitch following error of blade 1 with respect to time, filtering the result, and obtaining the rate of change of the pitch following error of blade 1; taking the derivative of the expected pitch following error of blade 2 with respect to time, filtering the result, and obtaining the rate of change of the pitch following error of blade 2; taking the derivative of the expected pitch following error of blade 3 with respect to time, filtering the result, and obtaining the rate of change of the pitch following error of blade 3; wherein, the filter can select a first-order low-pass filter, a second-order low-pass filter, or a sliding average filter to remove high-frequency noise signals.

[0068] The calculation formula of the pitch following error change rate is as follows:

[0069]

[0070] In the above formula, represents the rate of change of the pitch following error of blade 1; represents the rate of change of the pitch following error of blade 2; represents the rate of change of the pitch following error of blade 3; Filter(·) represents the filter function; represents the expected following error of blade 1; represents the expected following error of blade 2; represents the expected following error of blade 3 in pitch control.

[0071] When a wind turbine is operating normally, the rate of change of the pitch following error of each blade is very close to zero; when a blade runaway failure occurs, the rate of change of the pitch following error of the three blades will quickly deviate from zero.

[0072] 3) Based on the pitch following error change rate obtained in step 2), determine whether blade 1, blade 2, and blade 3 have runaway faults at the same time, and obtain a unified blade runaway fault flag, which is triggered by a positive unified blade runaway fault flag or a negative unified blade runaway fault flag.

[0073] A unified blade runaway fault can be identified as follows: if blades 1, 2, and 3 all runaway at the positive maximum pitch rate, the rate of change of the pitch following error for all three blades will deviate from zero and be significantly above zero, indicating a positive unified blade runaway fault. If blades 1, 2, and 3 all runaway at the negative maximum pitch rate, the rate of change of the pitch following error for all three blades will deviate from zero and be significantly below zero, indicating a negative unified blade runaway fault. By setting upper and lower thresholds, a unified blade runaway fault can be identified.

[0074] The forward unified blade runaway fault flag is defined as follows:

[0075]

[0076] In the above formula, Indicates the positive unified blade runaway fault flag, identifying three blades running away at a positive pitch rate; represents the rate of change of the pitch following error of blade 1; represents the rate of change of the pitch following error of blade 2; represents the rate of change of the pitch following error of blade 3; C H Indicates the upper threshold of the pitch following error change rate; if indicates the following judgment condition; & indicates a logical AND operation; else indicates other situations.

[0077] The negative unified blade runaway fault flag is defined as follows:

[0078]

[0079] In the above formula, Indicates the negative unified blade runaway fault flag, identifying three blades running away at a negative pitch rate; represents the rate of change of the pitch following error of blade 1; represents the rate of change of the pitch following error of blade 2; represents the rate of change of the pitch following error of blade 3; C L Indicates the lower limit threshold of the pitch following error change rate; if indicates the following judgment condition; & indicates a logical AND operation; else indicates other situations.

[0080] 4) Based on the unified blade runaway fault flag obtained in step 3), a unified runaway fault shutdown flag is obtained, and the wind turbine generator set is triggered to enter the unified runaway fault shutdown logic until the unit is completely shut down.

[0081] When the positive unified blade runaway fault flag or the negative unified blade runaway fault flag is triggered, the unified runaway fault shutdown flag is triggered. The definition of the unified runaway fault shutdown flag is as follows:

[0082]

[0083] In the above formula, Flag is the unified runaway fault shutdown flag; Indicates the forward unified blade runaway fault flag; Indicates the negative unified blade runaway fault flag; or represents the logical OR operation; when it is identified that three blades are runaway at a positive pitch rate or at a negative pitch rate, the unified runaway shutdown flag will be triggered and the wind turbine will enter the unified runaway fault shutdown logic.

[0084] When the wind turbine enters the unified runaway fault shutdown logic, the pitch rate setting value during the shutdown process is a table lookup value, which is obtained by looking up the table based on the current pitch angle. The specific definition is as follows:

[0085]

[0086] In the above formula, Indicates the blade 1 pitch rate setting value for the unified runaway fault shutdown process;

[0087] Indicates the blade 2 pitch rate setting value for the unified runaway fault shutdown process; Indicates the blade 3 pitch rate setting value for the unified runaway fault shutdown process; Lookup_P represents the unified runaway fault shutdown pitch rate lookup table function; Indicates the current pitch angle of blade 1, measured by the sensor; Indicates the current pitch angle of blade 2, measured by the sensor; Indicates the current pitch angle of blade 3, measured by the sensor.

[0088] When the wind turbine enters the unified runaway fault shutdown logic, the generator torque setting value during the shutdown process is a table lookup value, which is obtained by looking up the table according to the current generator speed. The specific definition is as follows:

[0089]

[0090] In the above formula, Represents the generator torque setting value for the unified runaway fault shutdown process; Lookup_T represents the unified runaway fault shutdown generator torque lookup function; Indicates the current generator speed, measured by the sensor.

[0091] Example 2

[0092] This embodiment discloses a wind turbine unified blade runaway fault identification system, which is used to implement the wind turbine unified blade runaway fault identification method described in Example 1. Figure 1 As shown, the system includes the following functional modules:

[0093] The pitch expected following error module calculates the pitch expected following error of each blade based on the pitch command of each blade output by the pitch controller and the current pitch angle of each blade measured by the sensor;

[0094] The pitch following error change rate module calculates the derivative of the pitch expected following error of each blade based on the pitch expected following error obtained by the pitch expected following error module, and obtains the pitch following error change rate after filtering;

[0095] The unified blade runaway fault identification module determines whether blades 1, 2, and 3 have runaway faults at the same time based on the pitch following error change rate obtained by the pitch following error change rate module, and obtains the unified blade runaway fault flag, which triggers a positive unified blade runaway fault flag or a negative unified blade runaway fault flag.

[0096] The unified blade runaway fault shutdown module obtains the unified blade runaway fault flag based on the unified blade runaway fault identification module, and triggers the wind turbine generator set to enter the unified runaway fault shutdown logic until the unit is completely shut down.

[0097] Example 3

[0098] This embodiment discloses a storage medium storing a program. When the program is executed by a processor, the method for identifying a unified blade runaway fault of a wind turbine generator set described in Example 1 is implemented.

[0099] The storage medium in this embodiment can be a magnetic disk, an optical disk, a computer memory, a read-only memory (ROM), a random access memory (RAM), a USB flash drive, a mobile hard disk, or the like.

[0100] Example 4

[0101] This embodiment discloses a computing device, including a processor and a memory for storing a program executable by the processor. When the processor executes the program stored in the memory, the method for identifying a unified blade runaway fault of a wind turbine generator set described in Example 1 is implemented.

[0102] The computing device described in this embodiment may be a desktop computer, a laptop computer, a smart phone, a PDA handheld terminal, a tablet computer, a programmable logic controller (PLC), or other terminal devices with a processor function.

[0103] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A method for identifying a wind turbine blade runaway fault, characterized in that: Do the following: 1) Calculate the expected following error of each blade’s pitch based on the pitch command and the current pitch angle of each blade; 2) Based on the desired pitch following error obtained in step 1), the derivative of the desired pitch following error of each blade is calculated, and the rate of change of the pitch following error is obtained after filtering; 3) Based on the pitch following error change rate obtained in step 2), determine whether the first blade, the second blade, and the third blade have runaway faults at the same time, obtain a unified blade runaway fault flag, and determine whether the unified blade runaway fault flag is triggered in a positive direction or a negative direction; The identification method for a unified blade runaway fault is as follows: if the first, second, and third blades all run away at the positive maximum pitch rate, the rate of change of the pitch following error of the three blades will deviate from zero and be significantly higher than zero, which is a positive unified blade runaway fault; if the first, second, and third blades all run away at the negative maximum pitch rate, the rate of change of the pitch following error of the three blades will deviate from zero and be significantly lower than zero, which is a negative unified blade runaway fault. By setting the upper and lower thresholds, a unified blade runaway fault can be identified. The forward unified blade runaway fault flag is defined as follows: In the above formula, Indicates the positive unified blade runaway fault flag, identifying three blades running away at a positive pitch rate; represents the rate of change of the pitch following error of the first blade; represents the rate of change of the pitch following error of the second blade; represents the rate of change of the pitch following error of the third blade; C H Indicates the upper threshold of the pitch following error change rate; if indicates the following judgment condition; & indicates the logical AND operation; else indicates other conditions; The negative unified blade runaway fault flag is defined as follows: In the above formula, Indicates the negative unified blade runaway fault flag, identifying three blades running away at a negative pitch rate; C L Indicates the lower threshold of the pitch following error change rate; 4) Based on the unified blade runaway fault flag obtained in step 3), a unified runaway fault shutdown flag is obtained, and the wind turbine generator set is triggered to enter the unified runaway fault shutdown logic until the unit is completely shut down.

2. The method for identifying a wind turbine blade runaway fault according to claim 1, characterized in that: In step 1), the pitch command of each blade is subjected to the pitch second-order transfer function to obtain the desired pitch angle of each blade; then the desired pitch angle of each blade is subtracted from the current pitch angle measured for the corresponding blade to obtain the desired pitch following error of each blade; The second-order transfer function of the pitch control is defined as follows: In the above formula, H(s) represents the second-order transfer function of pitch; ω n represents the natural frequency of the pitch system; ξ represents the damping ratio of the pitch system; s represents the Laplace variable; e -τs represents the delay link, and the delay time constant is τ; wherein, the natural frequency, damping ratio and delay time constant of the pitch system can be obtained through the step response test of the pitch system; The calculation formula of the expected following error of the pitch control is as follows: In the above formula, represents the expected following error of the first blade’s pitch; represents the expected following error of the second blade’s pitch; represents the expected following error of the third blade’s pitch; The pitch command for the first blade is output by the pitch controller; Indicates the pitch command of the second blade, which is output by the pitch controller; The pitch command for the third blade is output by the pitch controller; Indicates the current pitch angle of the first blade, measured by the sensor; Indicates the current pitch angle of the second blade, measured by the sensor; Indicates the current pitch angle of the third blade, measured by the sensor.

3. The method for identifying a wind turbine blade runaway fault according to claim 1, characterized in that: In step 2), the derivative of the desired pitch following error of the first blade with respect to time is obtained, and the result is filtered to obtain the rate of change of the pitch following error of the first blade; the derivative of the desired pitch following error of the second blade with respect to time is obtained, and the result is filtered to obtain the rate of change of the pitch following error of the second blade; the derivative of the desired pitch following error of the third blade with respect to time is obtained, and the result is filtered to obtain the rate of change of the pitch following error of the third blade; The calculation formula of the pitch following error change rate is as follows: In the above formula, represents the rate of change of the pitch following error of the first blade; represents the rate of change of the pitch following error of the second blade; represents the rate of change of the pitch following error of the third blade; Filter(·) represents the filter function; represents the expected following error of the first blade’s pitch; represents the expected following error of the second blade’s pitch; represents the expected following error of the third blade’s pitch; When a wind turbine is operating normally, the rate of change of the pitch following error of each blade is close to zero; When a blade runaway failure occurs, the rate of change of the pitch following error of the three blades will deviate from zero rapidly.

4. The method for identifying a wind turbine blade runaway fault according to claim 3, characterized in that: The filter is a first-order low-pass filter, a second-order low-pass filter or a sliding average filter to remove high-frequency noise signals.

5. The method for identifying a wind turbine blade runaway fault according to claim 1, characterized in that: In step 4), when the positive unified blade runaway fault flag or the negative unified blade runaway fault flag is triggered, the unified runaway fault shutdown flag is triggered; the unified runaway fault shutdown flag is defined as follows: In the above formula, Flag is the unified runaway fault shutdown flag; Indicates the forward unified blade runaway fault flag; Indicates the negative unified blade runaway fault flag; or represents the logical OR operation; when it is identified that three blades are uniformly runaway at a positive pitch rate or at a negative pitch rate, the unified runaway fault shutdown flag will be triggered, and the wind turbine will enter the unified runaway fault shutdown logic; When the wind turbine enters the unified runaway fault shutdown logic, the pitch rate setting value during the shutdown process is a table lookup value. The pitch rate setting value is obtained by looking up the table according to the current pitch angle. The specific definition is as follows: In the above formula, Indicates the first blade pitch rate setting value of the unified runaway fault shutdown process; Indicates the second blade pitch rate setting value for the unified runaway fault shutdown process; Indicates the third blade pitch rate setting value for the unified runaway fault shutdown process; Lookup_P represents the unified runaway fault shutdown pitch rate lookup table function; Indicates the current pitch angle of the first blade, measured by the sensor; Indicates the current pitch angle of the second blade, measured by the sensor; Indicates the current pitch angle of the third blade, measured by the sensor; When the wind turbine enters the unified runaway fault shutdown logic, the generator torque setting value during the shutdown process is a table lookup value. The generator torque setting value is obtained by looking up the table according to the current generator speed. The specific definition is as follows: In the above formula, Represents the generator torque setting value for the unified runaway fault shutdown process; Lookup_T represents the unified runaway fault shutdown generator torque lookup function; Indicates the current generator speed, measured by the sensor.

6. A wind turbine unified blade runaway fault identification system, characterized in that: A method for identifying a unified blade runaway fault of a wind turbine generator set according to any one of claims 1 to 5, comprising: The expected pitch following error module calculates the expected pitch following error of each blade based on the pitch command of each blade and the current pitch angle of each blade; The pitch following error change rate module calculates the derivative of the pitch expected following error of each blade based on the pitch expected following error obtained by the pitch expected following error module, and obtains the pitch following error change rate after filtering; The unified blade runaway fault identification module determines whether the first blade, the second blade, and the third blade have runaway faults at the same time based on the pitch following error change rate obtained by the pitch following error change rate module, obtains the unified blade runaway fault flag, and triggers the positive unified blade runaway fault flag or the negative unified blade runaway fault flag; The unified blade runaway fault shutdown module obtains the unified blade runaway fault flag based on the unified blade runaway fault identification module, and triggers the wind turbine generator set to enter the unified runaway fault shutdown logic until the unit is completely shut down.

7. A storage medium storing a program, characterized in that: When the program is executed by a processor, the method for identifying a unified blade runaway fault of a wind turbine generator set according to any one of claims 1 to 5 is implemented.

8. A computing device comprising a processor and a memory for storing a program executable by the processor, characterized in that: When the processor executes the program stored in the memory, the method for identifying a unified blade runaway fault of a wind turbine generator set according to any one of claims 1 to 5 is implemented.

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