A wind turbine generator coupling slip identification and protection method and device and wind turbine generator

Abstract

The application provides a wind turbine coupling slip identification and protection method and device and a wind turbine, so that the wind turbine coupling slip can be identified and protected in advance before the coupling slip occurs without adding an input side sensor. The method comprises the following steps: acquiring a high-speed shaft real-time rotating speed, a converter real-time power, a converter real-time torque and a cabin temperature of the wind turbine; determining an instantaneous total load torque and a dynamic critical slip torque of the wind turbine respectively according to the high-speed shaft real-time rotating speed, the converter real-time power, the converter real-time torque and the cabin temperature; determining a coupling slip risk level according to the instantaneous total load torque and the dynamic critical slip torque; and performing a corresponding coupling protection action according to the coupling slip risk level.

Description

Technical Field

[0001] This application relates to the field of wind turbine generators, specifically to a method, device, and wind turbine generator for identifying and protecting against slippage in the coupling of a wind turbine generator set. Background Technology

[0002] As a crucial component of the transmission system, the high-speed shaft coupling of a wind turbine plays a vital role in transmitting torque and buffering shocks. Frequent slippage of the coupling can lead to decreased transmission efficiency and even erosion of the friction plates, seriously affecting the safe and stable operation of the unit.

[0003] In existing technologies, methods for protecting couplings from slippage are mainly divided into two categories:

[0004] One type is based on input loads (such as blade root loads and rotor aerodynamic torque) to identify slippage risk. This type of identification method requires the addition of dedicated sensors on the input side of the blades and rotor, which has problems such as complex installation, high cost, and difficult maintenance. At the same time, this method only considers the load at the input end (rotor side), but the load at the input end changes slowly and cannot reflect the rapid torque fluctuations on the high-speed shaft side, resulting in low identification accuracy and difficulty in timely capturing transient slippage risk.

[0005] Another type is based on comparing the generator speed and the wind turbine speed. Protection is initiated after a significant speed difference between the generator and wind turbine speeds occurs due to coupling slippage. However, this method is reactive protection; by this time, slippage has already occurred, the friction plates have worn, and the protection action is delayed, failing to achieve early identification and proactive intervention of slippage risks.

[0006] In summary, the existing technology lacks a wind turbine coupling slippage identification and protection scheme that does not require additional input-side sensors and can achieve early identification and graded protection before slippage occurs. Summary of the Invention

[0007] This application provides a method, device, and wind turbine for identifying and protecting the slippage of the coupling in a wind turbine generator set, so as to achieve early identification and graded protection before the slippage of the coupling occurs without adding an input-side sensor.

[0008] The technical solution of this invention is as follows:

[0009] This application provides a method for identifying and protecting against slippage in wind turbine couplings, including:

[0010] Obtain the real-time high-speed shaft speed, real-time converter power, real-time converter torque, and nacelle temperature of the wind turbine.

[0011] The instantaneous total load torque and dynamic critical slippage torque of the wind turbine are determined based on the real-time speed of the high-speed shaft, the real-time power of the converter, the real-time torque of the converter, and the nacelle temperature, respectively.

[0012] The slippage risk level of the coupling is determined based on the instantaneous total load torque and the dynamic critical slippage torque.

[0013] Based on the slippage risk level of the coupling, the corresponding coupling protection action is executed.

[0014] Preferably, the steps of determining the instantaneous total load torque and dynamic critical slippage torque of the wind turbine based on the real-time rotational speed of the high-speed shaft, the real-time power of the converter, the real-time torque of the converter, and the nacelle temperature include:

[0015] Calculate the steady-state load torque based on the real-time speed of the high-speed shaft and the real-time power of the converter;

[0016] The rotational speed change rate is calculated based on the real-time rotational speed of the high-speed shaft, and the inertial impact torque is calculated based on the rotational speed change rate.

[0017] Calculate the instantaneous total load torque based on the steady-state load torque and the inertial impact torque;

[0018] The torque change rate is calculated based on the real-time torque of the converter, and the friction coefficient is dynamically corrected based on the torque change rate to obtain the dynamic friction coefficient.

[0019] The dynamic critical slippage torque is calculated based on the dynamic friction coefficient and the cabin temperature.

[0020] Preferably, the step of determining the slippage risk level of the coupling based on the instantaneous total load torque and the dynamic critical slippage torque includes:

[0021] The ratio of the instantaneous total load torque to the dynamic critical slippage torque is calculated and used as the slippage risk coefficient.

[0022] The slippage risk coefficient is compared with a preset risk threshold.

[0023] When the slippage risk coefficient is less than the first preset threshold, the coupling is determined to be in a safe state;

[0024] When the slippage risk coefficient is greater than or equal to the first preset threshold and less than the second preset threshold, the coupling is determined to be in a slippage warning state.

[0025] When the slippage risk coefficient is greater than or equal to the second preset threshold, the coupling is determined to be in a slippage fault state.

[0026] Wherein, the first preset threshold is less than the second preset threshold, and both the first preset threshold and the second preset threshold are positive numbers less than or equal to 1.

[0027] Preferably, the steps for performing corresponding coupling protection actions based on the coupling slippage risk level include:

[0028] When the coupling is determined to be in a safe state, the current operating state of the wind turbine is maintained and no protection action is performed.

[0029] When the coupling is determined to be in a slippage warning state, a first-level protection action is executed. The first-level protection action includes: sending a power reduction operation command to the wind turbine main control system, controlling the turbine to reduce the output power to the target power value at a preset power reduction rate, and continuously monitoring the slippage risk coefficient; if the slippage risk coefficient drops below the safe state threshold within a preset time period, the warning is lifted and the power is restored; if the slippage risk coefficient does not drop below the safe state threshold within the preset time period, the power reduction operation is maintained and monitoring continues.

[0030] When the coupling is determined to be in a slippage fault state, a secondary protection action is executed. The secondary protection action includes: sending an emergency stop command to the wind turbine main control system, controlling the unit to execute the emergency stop procedure, cutting off power output, and recording the current operating data and slippage event log.

[0031] Preferably, when it is determined that the coupling is in a slippage warning state and no emergency stop has been executed, the method further includes:

[0032] The cabin temperature is compared with a preset temperature threshold.

[0033] When the cabin temperature is greater than the first preset temperature threshold, the temperature correction coefficient in the dynamic critical slip torque is reduced by a preset step size.

[0034] When the cabin temperature is greater than the second preset temperature threshold, the temperature correction coefficient is further reduced by a preset step size, wherein the second preset temperature threshold is greater than the first preset temperature threshold.

[0035] The dynamic critical slip torque is recalculated using the updated temperature correction coefficient, and the recalculated dynamic critical slip torque is used for subsequent slip risk level determination.

[0036] Preferably, the method further includes:

[0037] Record slip events in a log, which includes the cumulative number of slips and the cumulative duration of slips;

[0038] Based on the slippage event log, the wear aging correction coefficient in the dynamic critical slippage torque is updated:

[0039] Wherein, for each increase in the cumulative number of slips, the wear and aging correction coefficient is reduced by one level according to a preset step size; and / or for each increase in the cumulative slip duration by a preset duration, the wear and aging correction coefficient is reduced by one level according to a preset step size;

[0040] The dynamic critical slippage torque is recalculated using the updated wear and aging correction coefficient, and the recalculated dynamic critical slippage torque is used for subsequent slippage risk level determination.

[0041] When the cumulative number of slippages exceeds a preset threshold, or the cumulative slippage duration exceeds a preset duration threshold, a coupling maintenance reminder message is output.

[0042] Preferably, the step of calculating the steady-state load torque based on the real-time speed n of the high-speed shaft and the real-time power of the converter includes:

[0043] The real-time rotational speed of the high-speed shaft is time-differentized, and the rate of change of rotational speed dn / dt is calculated.

[0044] Obtain the total rotational inertia J on the high-speed shaft side;

[0045] The inertial impact moment Tinertia is calculated using the following formula:

[0046]

[0047] Where ω is the angular velocity and n is the real-time rotational speed of the high-speed shaft;

[0048] The steps for calculating the instantaneous total load torque based on the steady-state load torque and the inertial impact torque include:

[0049] Calculate the instantaneous total load torque T using the following formula. load :

[0050]

[0051] Among them, T steady For the steady-state load torque, T inertia The inertial impact torque;

[0052] The steps of calculating the torque change rate based on the real-time torque of the converter, and dynamically correcting the friction coefficient based on the torque change rate to obtain the dynamic friction coefficient include:

[0053] The real-time torque T of the converter is time-differentiated, and the torque change rate dT / dt is calculated.

[0054] The static friction coefficient μ is determined based on the absolute value of the torque change rate dT / dt. s Dynamic attenuation correction is performed to obtain the dynamic friction coefficient μ. d :

[0055]

[0056] Where, μ s β is the static friction coefficient, and β is the friction material rate attenuation coefficient;

[0057] The steps for calculating the dynamic critical slippage torque based on the dynamic friction coefficient and the cabin temperature include:

[0058] Obtain the inherent structural parameters of the coupling, including the number of friction surfaces z and the total axial preload F of the friction plates. n and the average radius r of the friction surface m ;

[0059] The correction factor for the coupling is obtained, the correction factor including the centrifugal correction factor K determined based on the real-time rotational speed. n The temperature correction factor Kt and the wear and aging correction factor K are determined based on the cabin temperature. w ;

[0060] According to the dynamic friction coefficient μ d Number of friction surfaces z, total axial preload F of friction plates n and the average radius r of the friction surface m Centrifugal correction factor K n Temperature correction factor Kt and wear aging correction factor K w Calculate the dynamic critical slippage torque T slip_dynamic :

[0061] .

[0062] Preferably, the centrifugal correction coefficient K is... n Determined according to the following formula:

[0063]

[0064] Where k1 is the centrifugal correction constant, with a value ranging from 0.12 to 0.18; n is the real-time rotational speed of the high-speed shaft; n e This refers to the rated speed of the high-speed shaft.

[0065] When the cabin temperature is less than or equal to the first temperature threshold, the centrifugal speed correction coefficient K t The value is 1;

[0066] When the cabin temperature is greater than the first temperature threshold and less than or equal to the second temperature threshold, the centrifugal speed correction coefficient K is... t Take the first correction value;

[0067] When the cabin temperature is greater than the second temperature threshold, the centrifugal speed correction coefficient K... t Take the second correction value;

[0068] Wherein, the first temperature threshold is less than the second temperature threshold, and the second correction value is less than the first correction value.

[0069] This application also provides a wind turbine coupling slippage identification and protection device, including:

[0070] The acquisition module is used to acquire the real-time high-speed shaft speed, real-time converter power, real-time converter torque, and nacelle temperature of the wind turbine.

[0071] The calculation module is used to determine the instantaneous total load torque and dynamic critical slippage torque of the wind turbine based on the real-time speed of the high-speed shaft, the real-time power of the converter, the real-time torque of the converter, and the nacelle temperature, respectively.

[0072] The risk level classification module is used to determine the slippage risk level of the coupling based on the instantaneous total load torque and the dynamic critical slippage torque.

[0073] The protection module is used to perform corresponding coupling protection actions based on the coupling slippage risk level.

[0074] This application also provides a wind turbine generator set, including the aforementioned wind turbine generator set coupling slippage identification and protection device.

[0075] The beneficial effects of this invention are as follows:

[0076] By utilizing the existing real-time output of the wind turbine, including real-time speed, inverter power, inverter torque, and nacelle temperature, all of which can be directly obtained from the wind turbine's existing sensors and monitoring and data acquisition systems, no additional sensor hardware needs to be added to the input side such as the blades or rotor. Slippage identification based on existing output information fundamentally avoids the hardware, installation, and maintenance costs associated with adding sensors. Furthermore, since no hardware modifications to existing wind turbines are required, on-site deployment is simpler, implementation is shorter, and it is easier to promote and apply to existing turbines.

[0077] The risk level of slippage is determined by separately determining the instantaneous total load torque and the dynamic critical slippage torque, and comparing the two. Specifically, the instantaneous total load torque reflects the actual load currently acting on the coupling, while the dynamic critical slippage torque reflects the maximum torque the coupling can bear under the current condition. By comparing the actual load with the bearing limit in real time, slippage risk can be identified in advance when the actual load approaches but has not yet exceeded the bearing limit. This mechanism allows protective actions to be executed before slippage occurs, thereby preventing slippage events from actually happening and fundamentally solving the protection lag problem of post-event protection schemes.

[0078] Real-time speed, real-time power of the converter, and real-time torque of the converter are all collected from the high-speed shaft side. Among them, the real-time torque of the converter directly reflects the change in electromagnetic torque on the generator side. This signal is located at the output end of the drive train and is directly related to the coupling. It does not need to be transmitted and attenuated through multiple stages of transmission components, and can more quickly reflect the load changes borne by the coupling. Based on the output end signal, slippage risk identification has a shorter response path and can capture transient changes in coupling load more promptly, improving the response speed and accuracy of slippage risk identification. Attached Figure Description

[0079] Figure 1 This is a flowchart illustrating the method of an embodiment of this application;

[0080] Figure 2 This is a structural block diagram of the device in the embodiments of this application. Detailed Implementation

[0081] Reference Figure 1 This application provides a method for identifying and protecting against slippage in wind turbine couplings, including:

[0082] S101, obtain the real-time speed of the high-speed shaft of the wind turbine, the real-time power of the converter, the real-time torque of the converter, and the nacelle temperature;

[0083] S102, based on the real-time speed of the high-speed shaft, the real-time power of the converter, the real-time torque of the converter, and the nacelle temperature, determine the instantaneous total load torque and dynamic critical slippage torque of the wind turbine respectively;

[0084] S103, determine the slippage risk level of the coupling based on the instantaneous total load torque and the dynamic critical slippage torque;

[0085] S104, based on the slippage risk level of the coupling, execute the corresponding coupling protection action.

[0086] In step S101, the real-time speed n of the high-speed shaft is acquired by a speed sensor at the generator shaft end. The real-time power P and torque T of the converter are read directly from the internal variables of the wind turbine converter controller. The nacelle temperature t is acquired by a temperature sensor located inside the wind turbine nacelle. All of the above parameters are data that can be provided by the existing sensors and control systems of the wind turbine, and there is no need to specifically limit the acquisition method for any single parameter.

[0087] Step S102 includes:

[0088] S1021, Calculate the steady-state load torque based on the real-time speed of the high-speed shaft and the real-time power of the converter;

[0089] S1022, calculate the speed change rate based on the real-time speed of the high-speed shaft, and calculate the inertial impact torque based on the speed change rate;

[0090] S1023, Calculate the instantaneous total load torque based on the steady-state load torque and the inertial impact torque;

[0091] S1024, calculate the torque change rate based on the real-time torque of the converter, and dynamically correct the friction coefficient based on the torque change rate to obtain the dynamic friction coefficient.

[0092] S1025, Calculate the dynamic critical slippage torque based on the dynamic friction coefficient and the cabin temperature.

[0093] During normal operation of the wind turbine, both the real-time high-speed shaft speed *n* and the real-time converter power *P* are dynamic quantities that change with time. This step substitutes these two values ​​into the following formula to calculate the steady-state load torque:

[0094]

[0095] Where Tsteady is the steady-state load torque in Newton-meters (N·m); P is the real-time power of the converter in kilowatts (kW); and n is the real-time speed of the high-speed shaft in revolutions per minute (r / min). The coefficient 9550 in this formula is derived from the unit conversion relationship between power, speed, and torque, and is a well-known physical calculation formula in this field.

[0096] In practice, the wind turbine's main control system or condition monitoring server acquires the P and n values ​​at each sampling period. Substituting these values ​​into the formula above yields the steady-state load torque at that moment. This steady-state load torque reflects the basic steady-state torque that the coupling needs to transmit under the current output power and speed. Higher power or lower speed results in a larger steady-state load torque, a heavier foundation load on the coupling, and a higher risk of foundation slippage.

[0097] In actual operation of wind turbine units, the high-speed shaft speed is not constant due to wind speed fluctuations and pitch control. When the speed changes rapidly, the inertia of the rotating components on the high-speed shaft side generates an additional impact torque, which is superimposed on the steady-state load torque, significantly increasing the instantaneous total load on the coupling. Step S1022, the step of calculating the steady-state load torque based on the real-time high-speed shaft speed n and the real-time power of the converter, includes:

[0098] The real-time rotational speed of the high-speed shaft is time-differentized, and the rate of change of rotational speed dn / dt is calculated:

[0099]

[0100] Where n(t) is the rotational speed at the current moment, n(t-Δt) is the rotational speed at the previous sampling moment, and Δt is the sampling time interval. This time difference method is a conventional method for calculating the derivative of a signal in the field of digital signal processing. It has high computational efficiency and is suitable for real-time execution in embedded systems.

[0101] The high-speed shaft side total rotational inertia J is obtained. J is an inherent physical parameter of the wind turbine transmission system, which does not change with operating conditions and is directly obtained from the factory technical parameters.

[0102] After obtaining the rate of change of rotational speed, the inertial impact torque T is calculated according to the following formula. inertia :

[0103]

[0104] Where ω is the angular velocity and n is the real-time rotational speed of the high-speed shaft.

[0105] The dynamic changes in rotational speed are quantified as inertial impact torque, enabling the calculation of the instantaneous total load torque to reflect the contribution of transient speed changes to the load. This step directly calculates the rate of change of rotational speed from the high-speed shaft speed, which can quickly respond to speed fluctuations on the high-speed shaft side and promptly reflect the impact of transient impact loads on slippage risk.

[0106] The total load torque borne by the coupling at any given moment is equal to the linear superposition of the steady-state transmitted torque and the transient inertial impact torque. The steady-state load torque represents the basic torque that the wind turbine needs to stably transmit under the current power generation conditions, while the inertial impact torque represents the additional dynamic torque generated by changes in rotational speed. The two have different physical sources, but both act on the same coupling. Therefore, under the premise of consistent dimensions, they can be directly added together to obtain the actual total load torque borne by the coupling at the current moment.

[0107] In step S1023, the step of calculating the instantaneous total load torque based on the steady-state load torque and the inertial impact torque includes:

[0108] Calculate the instantaneous total load torque T using the following formula. load :

[0109]

[0110] Among them, T steady For the steady-state load torque, T inertia The inertial impact torque is given.

[0111] In step S1024, during the operation of the coupling, the friction coefficient is not a constant, but a dynamic quantity significantly affected by the torque change rate. When the torque changes rapidly, the microscopic contact state of the friction pair surface changes, and the static friction state transitions to the dynamic friction state, causing the friction coefficient to drop instantaneously. The steps of calculating the torque change rate based on the real-time torque of the converter and dynamically correcting the friction coefficient based on the torque change rate to obtain the dynamic friction coefficient include:

[0112] The real-time torque T of the converter is time-differentiated, and the torque change rate dT / dt is calculated:

[0113]

[0114] Where T(t) is the real-time torque value of the converter at the current moment, T(t-Δt) is the real-time torque value of the converter at the previous sampling moment, and Δt is the sampling time interval. This calculation method is the same as the calculation method of the speed change rate, both of which perform time difference on the real-time acquired signal.

[0115] The static friction coefficient μ is determined based on the absolute value of the torque change rate dT / dt. s Dynamic attenuation correction is performed to obtain the dynamic friction coefficient μ. d :

[0116]

[0117] Where, μ s β is the static friction coefficient, and β is the friction material rate attenuation coefficient.

[0118] The larger the absolute value of the torque change rate, the more drastic the torque fluctuation, and the more difficult it is for the microscopic uneven structure of the friction pair surface to maintain a stable static contact state. The degree of decrease in the static friction coefficient towards the dynamic friction coefficient is also more significant. When the torque change rate is zero (i.e., the torque is constant), the dynamic friction coefficient equals the static friction coefficient; as the torque change rate increases, the dynamic friction coefficient decreases linearly. This linear attenuation model is a commonly used simplified model in this field to describe the change of friction coefficient with loading rate. Its mathematical form is concise, the physical meaning of the parameters is clear, and it is convenient for real-time calculation in embedded systems. The friction material rate attenuation coefficient β in the formula is calibrated through bench tests and can be set differently for different friction material characteristics.

[0119] In step S1025, the critical slippage torque of the coupling is affected not only by the dynamic friction coefficient but also by a combination of factors, including the geometric parameters of the friction pair, preload, centrifugal effect of rotational speed, ambient temperature, and long-term wear. This step incorporates all of these factors into the calculation of the dynamic critical slippage torque.

[0120] Step S1025, which calculates the dynamic critical slippage torque based on the dynamic friction coefficient and the cabin temperature, includes:

[0121] Obtain the inherent structural parameters of the coupling, including the number of friction surfaces z and the total axial preload F of the friction plates. n and the average radius r of the friction surface m ;

[0122] The correction factor for the coupling is obtained, the correction factor including the centrifugal correction factor K determined based on the real-time rotational speed. n The temperature correction factor Kt and the wear and aging correction factor K are determined based on the cabin temperature. w ;

[0123] According to the dynamic friction coefficient μ d Number of friction surfaces z, total axial preload F of friction plates n and the average radius r of the friction surface m Centrifugal correction factor K n Temperature correction factor Kt and wear aging correction factor K w Calculate the dynamic critical slippage torque T slip_dynamic :

[0124] .

[0125] Among them, the product of the number of friction surfaces, the total axial preload, and the average radius of the friction surfaces. The coefficient of friction represents the theoretical load-bearing capacity of the coupling under static conditions, while the dynamic friction coefficient and various correction coefficients respectively introduce dynamic factors such as torque change rate, speed, temperature, and wear, as well as long-term factors, to correct for the theoretical load-bearing capacity.

[0126] Centrifugal correction factor K n This reflects the weakening effect of centrifugal force on the clamping force of the friction plates during high-speed rotation; its value decreases as the rotational speed increases. Temperature correction factor K t This reflects the effect of temperature increase on the decrease in the coefficient of friction of the friction material; its value decreases with increasing temperature. Wear aging correction factor K w This reflects the decrease in load-bearing capacity caused by friction pad wear and material aging during long-term operation. Its value decreases as the cumulative operating time or cumulative slippage increases.

[0127] Centrifugal correction factor K n Determined according to the following formula:

[0128]

[0129] Where k1 is the centrifugal correction constant, with a value ranging from 0.12 to 0.18; n is the real-time rotational speed of the high-speed shaft; n e This refers to the rated speed of the high-speed shaft.

[0130] When the cabin temperature is less than or equal to the first temperature threshold, the centrifugal speed correction coefficient K t The value is 1;

[0131] When the cabin temperature is greater than the first temperature threshold and less than or equal to the second temperature threshold, the centrifugal speed correction coefficient K is... t Take the first correction value;

[0132] When the cabin temperature is greater than the second temperature threshold, the centrifugal speed correction coefficient K... t Take the second correction value;

[0133] Wherein, the first temperature threshold is less than the second temperature threshold, and the second correction value is less than the first correction value.

[0134] In this embodiment of the application, step S103, which determines the slippage risk level of the coupling based on the instantaneous total load torque and the dynamic critical slippage torque, includes:

[0135] S1031, Calculate the ratio of the instantaneous total load torque to the dynamic critical slippage torque, as the slippage risk coefficient;

[0136] S1032, compare the slippage risk coefficient with a preset risk threshold;

[0137] S1033, when the slippage risk coefficient is less than the first preset threshold, the coupling is determined to be in a safe state;

[0138] S1034, when the slippage risk coefficient is greater than or equal to the first preset threshold and less than the second preset threshold, the coupling is determined to be in a slippage warning state.

[0139] S1035, when the slippage risk coefficient is greater than or equal to the second preset threshold, the coupling is determined to be in a slippage fault state;

[0140] Wherein, the first preset threshold is less than the second preset threshold, and both the first preset threshold and the second preset threshold are positive numbers less than or equal to 1.

[0141] In S1031, the instantaneous total load torque T is obtained through step S1023. load The dynamic critical slippage torque T is obtained through step S1025. slip_dynamic Next, this step calculates the ratio of the two as the slippage risk factor:

[0142]

[0143] Where R is the slip risk coefficient, which is dimensionless.

[0144] The instantaneous total load torque represents the total load actually borne by the coupling at the current moment, while the dynamic critical slippage torque represents the maximum torque limit that the coupling can withstand under the current condition. Dividing the two by the ratio R directly reflects how close the current load is to the bearing limit. When R is much less than 1, it indicates that the current load is far below the bearing limit, and the safety margin is sufficient; when R approaches 1, it indicates that the current load is close to the bearing limit, and the safety margin is insufficient; when R equals 1, it indicates that the load has reached the bearing limit and is in a critical slippage state; when R is greater than 1, it indicates that the load has exceeded the bearing limit, and slippage has occurred.

[0145] After obtaining the slippage risk coefficient R, this step compares it with a pre-set risk threshold. The risk threshold includes a first preset threshold R1 and a second preset threshold R2, where R1... <R2≤1。

[0146] The first preset threshold R1 is used to distinguish between a safe state and a warning state; its physical meaning is the lower limit of the safety margin. When R is lower than the first preset threshold R1, it is considered that there is sufficient safety margin between the current load and the bearing limit, and no intervention is required. The second preset threshold R2 is used to distinguish between a warning state and a fault state; its physical meaning is the danger boundary. When R reaches or exceeds the second preset threshold R2, it is considered that the load is extremely close to or has reached the bearing limit, slippage is about to occur or has already occurred, and immediate protective actions are required.

[0147] The first preset threshold R1 is set to 0.85, and the second preset threshold R2 is set to 0.95. The above specific values are general selections considered based on engineering experience and safety margins: 0.85 represents that a 15% safety margin is reserved, which is sufficient to cover load fluctuations under normal working conditions; 0.95 represents that only a 5% safety margin is reserved, and at this time, any slight disturbance may trigger slipping. However, those skilled in the art should understand that the above thresholds can be adaptively adjusted according to different coupling models, material properties of friction pairs, unit operation conditions and safety requirements. For example, for critical units with high reliability requirements, the thresholds can be appropriately reduced to give early warning, and for units that have accumulated sufficient operation data, the threshold settings can be optimized according to the statistical distribution, and these adjustments all fall within the protection scope of the present application. By setting dual thresholds, the continuously varying slipping risk coefficient is divided into three discrete grade intervals, so that the severity of the slipping risk is clearly defined, and a clear judgment basis is provided for the execution of graded protection actions.

[0148] When R < R1, it indicates that the current instantaneous total load torque is lower than R1 times the dynamic critical slipping torque, that is, there is sufficient safety margin between the actual load and the load-bearing limit. At this time, the coupling is in a normal working state with no slipping risk, and the current operation strategy can be maintained. The total load after the superposition of steady-state load and inertial impact is far lower than the current load-bearing capacity of the coupling, the friction plate is in a stable static friction state, the torque transmission is reliable, and no intervention measures are required.

[0149] When R1 ≤ R < R2, it indicates that the current instantaneous total load torque has reached a relatively high proportion of the dynamic critical slipping torque, the actual load is close to the load-bearing limit, and the safety margin is insufficient. At this time, although the coupling has not slipped yet, it is already in the slipping risk interval. If the load further increases or the load-bearing capacity further decreases, slipping may occur at any time. The load level has approached the load-bearing boundary of the coupling, and the friction plate is in the critical interval of transition from static friction to dynamic friction. In this state, it is necessary to issue an early warning and implement active intervention measures to actively reduce the load without immediate shutdown, so as to avoid the actual occurrence of slipping events. This judgment is the core link of the present method to realize early identification rather than post-protection — by setting the first preset threshold lower than the limit threshold, an early warning is issued before the load reaches the load-bearing limit, reserving time and space for active intervention.

[0150] When R ≥ R2, it indicates that the current instantaneous total load torque has reached or exceeded R2 times the dynamic critical slippage torque, meaning the actual load is extremely close to or even exceeds the bearing limit. At this point, slippage is highly likely to have already occurred or is about to occur within a short time, requiring immediate emergency protection actions. The load has approached or exceeded the bearing limit, the friction plates can no longer maintain a stable static friction state, and the coupling is about to enter or has already entered a slippage state. In this state, mild intervention measures such as reduced power operation are insufficient to avoid the risk, and an immediate emergency shutdown is required to protect equipment safety. This judgment serves as the last line of defense, ensuring that the equipment can be promptly shut down in the event of warning failure or rapid deterioration of the risk, avoiding serious failures such as friction plate burning caused by continued slippage.

[0151] In step S103, by setting a first preset threshold R1 lower than the limit threshold, potential risks can be identified before the load reaches its bearing limit, enabling protection actions to be executed before slippage occurs. This fundamentally solves the deficiency of the existing speed comparison method, which can only provide post-event protection after slippage occurs, and realizes the transformation from passive response to active prevention. The three-level risk classification allows protection actions to be executed according to the severity of the risk, avoiding unnecessary unit shutdowns and power generation losses caused by over-protection triggered by minor risks in a single threshold scheme, and also avoiding equipment damage due to insufficient protection actions for serious risks. The progression between the levels—maintaining operation in safe state, active intervention in early warning state, and emergency shutdown in fault state—is clear, and the protection strategy is reasonably matched with the risk level. The first preset threshold R1 and the second preset threshold R2 are both less than or equal to 1, meaning that both early warning and fault determination occur before or when the slippage risk coefficient reaches 1. This design ensures that slippage has not yet occurred when the early warning state is triggered, reserving time for active intervention measures such as power reduction; when the fault state is triggered, slippage is exactly at the critical state, and emergency shutdown can minimize friction plate wear. This threshold design is a key guarantee for achieving early detection of slippage.

[0152] In this embodiment of the application, step S104, which executes the corresponding coupling protection action based on the coupling slippage risk level, includes:

[0153] S1041, when the coupling is determined to be in a safe state, the current operating state of the wind turbine is maintained and no protection action is performed;

[0154] In S1042, when it is determined that the coupling is in a slip early warning state, a first-level protection action is executed. The first-level protection action includes: sending a power reduction operation instruction to the main control system of the wind turbine unit, controlling the unit to reduce the output power to a target power value at a preset power reduction rate, and continuously monitoring the slip risk coefficient; if the slip risk coefficient drops below the safety state threshold within a preset time period, the early warning is lifted and the power is restored; if the slip risk coefficient does not drop below the safety state threshold within the preset time period, the power reduction operation is maintained and the monitoring is continued;

[0155] In S1043, when it is determined that the coupling is in a slip fault state, a second-level protection action is executed. The second-level protection action includes: sending an emergency shutdown instruction to the main control system of the wind turbine unit, controlling the unit to execute an emergency shutdown procedure, cutting off power output, and recording the operation data and slip event log at the current moment.

[0156] In step S1041, when it is determined in step S103 that the coupling is in a safe state (i.e., R<R1), it indicates that the current instantaneous total load torque is much lower than the dynamic critical slip torque, and there is sufficient safety margin between the actual load and the load-bearing limit. At this time, the coupling is in a normal stable operation range, the friction plate is in a reliable static friction state, and torque transmission is safe and reliable. In this state, the main control system of the wind turbine unit or the condition monitoring server does not send any protection action instruction to the converter or the main control system, and the wind turbine unit maintains the current operation state unchanged and continues to perform normal power generation tasks. However, it should be noted that not executing protection actions does not mean stopping monitoring, and all sensors and calculation steps continue to operate to ensure timely response when the risk coefficient changes.

[0157] In step S1042, a power reduction operation instruction is sent to the main control system of the wind turbine unit to control the unit to reduce the output power to a target power value at a preset power reduction rate. The physical principle of power reduction is: according to the calculation formula of the steady-state load torque in step S1021 , when the rotation speed n does not change much, the steady-state load torque is approximately proportional to the power P. Reducing the power can directly reduce the steady-state load torque, and then reduce the instantaneous total load torque T load , so that the slip risk coefficient R decreases accordingly, thereby leaving the early warning range. The preset power reduction rate is preferably 5% to 10% of the rated power reduced per second. The selection of this rate takes into account both rapid response and system stability: if the rate is too slow, the risk coefficient will not drop in time, and slip may occur during the power reduction process; if the rate is too fast, it may cause unstable regulation of the converter or grid frequency fluctuation. The target power value is preferably 80% to 90% of the current power, and this reduction is sufficient to make the risk coefficient drop below the safety state threshold, while not excessively affecting the power generation.

[0158] When R drops below the safe state threshold within the preset duration (i.e., R<R1), it indicates that the power reduction measure has effectively reduced the load level, and the coupling has returned to the safe operation range. At this point, the early warning state is lifted, a power restoration instruction is sent to the main control system, and the power is gradually restored to the level before power reduction or the power set value optimized according to the current wind speed condition. The rate of power restoration is preferably consistent with or slightly lower than the power reduction rate, so as to avoid load impact caused by sudden power increase.

[0159] When R does not drop below the safe state threshold within the preset duration (i.e., R1≤R<R2 is still satisfied), it indicates that one-time power reduction fails to sufficiently reduce the risk coefficient. Possible reasons include the continuous increase of wind speed leading to the increase of steady-state load torque, the rapid change of rotational speed leading to the persistent existence of inertial impact torque, or the rise of nacelle temperature leading to the synchronous decrease of dynamic critical slipping torque. At this point, the current power reduction state is maintained, the change of R is continuously monitored, and the above judgment logic is repeatedly executed in subsequent operations. If R continues to fail to drop below the safe state threshold or further rises to the fault state threshold, the corresponding action is executed according to the latest judgment result.

[0160] The above preset duration is preferably 30 seconds to 60 seconds. The selection of this duration is based on engineering experience: on the one hand, it is long enough to observe the effect of the power reduction measure and the response trend of the risk coefficient, and on the other hand, it avoids protection delay caused by infinite waiting.

[0161] The load is actively reduced through power reduction operation, so that the coupling gets out of the risk range before slipping occurs, realizing advance avoidance of slipping rather than post-processing. Meanwhile, the continuous monitoring and condition restoration mechanism ensures the accuracy of protection actions: when the risk is eliminated, the power is restored in time to reduce power generation loss, and when the risk persists, the protection state is maintained to ensure safety. Compared with the passive protection mode based on rotational speed comparison in the prior art, this step advances the execution timing of the protection action from after slipping occurs to before slipping occurs, realizing the transformation from passive response to active prevention.

[0162] In step S1043, by controlling the converter to quickly disconnect the load, controlling the pitch system to perform an emergency pitch retraction action, and controlling the braking system to brake sequentially, the wind turbine's power output is cut off in the shortest possible time, allowing the coupling to unload quickly and preventing slippage from continuing to develop and causing friction plate ablation or secondary damage to other components of the transmission system. Furthermore, at the same time as triggering the emergency shutdown, the current operating data and slippage event log are recorded. Specifically, this includes recording all key parameters at the time the fault state is triggered, including the real-time speed of the high-speed shaft, the real-time power of the converter, the real-time torque of the converter, the nacelle temperature, the instantaneous total load torque, the dynamic critical slippage torque, the slippage risk coefficient, and the values ​​of each correction coefficient. The timestamp of the triggering time, the turbine number, and other operating status information are also recorded. This data is stored in the server's memory for subsequent accident analysis and maintenance decisions. The recorded operating data allows maintenance personnel to analyze the specific cause of the slippage fault (whether it is due to excessive load or reduced load-bearing capacity), determine whether friction plates need to be replaced or preload adjusted, and assess the timeliness and effectiveness of the protection actions.

[0163] Therefore, the most decisive protective measures are taken at the highest risk level to ensure equipment safety. Emergency shutdown can unload the coupling load in a short time, minimizing wear on the friction plates and impact on the transmission system caused by slippage. Simultaneously, complete recording of operating data provides data support for subsequent fault diagnosis and maintenance decisions, helping maintenance personnel accurately locate the cause of the fault and take targeted maintenance measures to prevent the recurrence of similar faults.

[0164] In this embodiment of the application, when it is determined that the coupling is in a slippage warning state and no emergency stop is executed, the method further includes:

[0165] S105, compare the cabin temperature with a preset temperature threshold;

[0166] S106, when the cabin temperature is greater than the first preset temperature threshold, the temperature correction coefficient K in the dynamic critical slip torque is adjusted. t The temperature is adjusted downward according to the preset step size; the first preset temperature threshold is preferably 60℃, which corresponds to the starting point when the friction coefficient of the friction material begins to show a significant decrease. When the temperature exceeds this temperature, the deterioration effect of temperature on the load-bearing capacity cannot be ignored, and the temperature correction coefficient Kt needs to be adjusted downward to reflect the decrease in load-bearing capacity.

[0167] S107, when the cabin temperature is greater than the second preset temperature threshold, the temperature correction coefficient K is adjusted. tThe temperature is further adjusted downwards according to a preset step size, wherein the second preset temperature threshold is greater than the first preset temperature threshold; the second preset temperature threshold is preferably 90°C, which corresponds to the high-temperature range where the friction coefficient of the friction material is severely reduced. If this temperature is exceeded, the friction pad is at risk of ablation, and the temperature correction coefficient K needs to be further adjusted downwards. t This is to reflect the sharp decline in load-bearing capacity. The preset step size for each downward adjustment is preferably 0.01 to 0.02, which allows for smooth adjustment of the temperature correction coefficient K according to temperature changes. t This avoids sudden changes in the protection threshold due to excessively large adjustments in a single instance.

[0168] S108, the dynamic critical slip torque is recalculated using the updated temperature correction coefficient, and the recalculated dynamic critical slip torque is used for subsequent slip risk level determination.

[0169] The purpose of steps S105-S108 is to trigger the temperature correction coefficient K in the dynamic critical slippage torque by real-time monitoring of the engine compartment temperature when the coupling is in a slippage warning state. t Dynamic adjustment is performed so that the critical slippage torque value can be adjusted in real time according to temperature changes. Temperature correction coefficient K t This study characterizes the effect of nacelle ambient temperature on the critical slippage torque of the coupling. As the nacelle temperature rises, the friction coefficient of the friction plate material decreases, and the preload changes due to thermal expansion, leading to a reduction in the coupling's load-bearing capacity. This step involves adjusting K in real-time based on the measured temperature. t This allows the value of the dynamic critical slippage torque to be adjusted synchronously with temperature changes, avoiding the calculated critical slippage torque being higher than the actual value due to the failure to consider temperature effects, thereby preventing protection delays caused by an artificially high protection threshold.

[0170] When the coupling is already in a warning state and the high-temperature environment further weakens its load-bearing capacity, the dynamic critical slippage torque can be reduced in real time, causing the slippage risk factor R to increase accordingly, thus more sensitively reflecting the additional risks brought about by the temperature rise. This avoids the protection lag caused by the calculated value not changing synchronously due to the decrease in the actual critical slippage torque caused by the temperature rise. At the same time, the two-level reduction mechanism distinguishes between two different operating conditions: general high temperature and severe high temperature. The correction range matches the severity of the temperature, neither overly sensitive nor overly sluggish, achieving refined temperature correction. In addition, this step works in conjunction with the power reduction measures in the first-level protection action: the power reduction reduces T from the load side. load Temperature correction reduces T from the load side. slip_dynamic Together, these two factors determine that R=T load / T slip_dynamic The changing trends enable protection decisions to comprehensively reflect the two-way changes in load and bearing capacity.

[0171] In this embodiment of the application, the method further includes:

[0172] S109, Record a slippage event log, the slippage event log including the cumulative number of slippages and the cumulative slippage duration;

[0173] S110, based on the slippage event log, update the wear aging correction coefficient in the dynamic critical slippage torque: wherein, for each increase in the cumulative slippage count, the wear aging correction coefficient is reduced by one level according to a preset step size; and / or for each increase in the cumulative slippage duration by a preset duration, the wear aging correction coefficient is reduced by one level according to a preset step size; the preset step size is preferably 0.01 to 0.02, that is, each slippage event causes K to... w Reduced by 1% to 2%.

[0174] Because relative sliding occurs between the friction plate and its mating component during each slippage event, wear occurs on the friction surface. Although the wear amount is limited in a single slippage, each slippage accumulates a small amount of material loss on the friction surface and irreversibly alters the microscopic contact state of the friction pair. The cumulative effect of multiple slippages will cause the friction plate's load-bearing capacity to continuously decrease. Therefore, the wear aging correction factor K needs to be adjusted after each slippage. w The adjustment was made downward to reflect the gradual decrease in load-bearing capacity.

[0175] The longer the slippage lasts, the more severe the wear and heat accumulation experienced by the friction plate under sliding friction. Prolonged slippage leads to a sharp increase in the surface temperature of the friction plate, accelerating material aging and wear depth. Therefore, the cumulative effect of the slippage duration also needs to be reflected in the wear aging correction factor K. w The attenuation is in progress. For example, if the coupling slips three times, with each slip lasting 2 minutes, 3 minutes, and 5 minutes respectively, the cumulative slip duration is 10 minutes, which will also trigger a downgrade.

[0176] The two update methods described above can be used individually or simultaneously. Both reflect the wear and aging degree of the friction pads, but each has its own emphasis: the cumulative slip count reflects the frequency of slip events; each slip event, whether lasting several seconds or minutes, causes impact wear on the friction pad. The cumulative slip duration reflects the total duration of slip events; prolonged slippage means the friction pad has experienced more heat accumulation and material loss under sliding friction conditions. Both are triggered independently and counted separately, together forming a comprehensive characterization of the wear and aging degree. A downward adjustment is executed when either condition is met, ensuring K... w The update can cover various physical mechanisms of friction plate performance degradation.

[0177] S111, the dynamic critical slippage torque is recalculated using the updated wear and aging correction coefficient, and the recalculated dynamic critical slippage torque is used for subsequent slippage risk level determination.

[0178] As the friction pads wear more rapidly, the dynamic critical slippage torque is adjusted downwards in real time. This results in a higher slippage risk factor for the same load level after wear, thus lowering the trigger threshold for protection actions. This ensures that the protection strategy can be triggered at a lower load threshold after the friction pads' load-bearing capacity decreases, avoiding situations where the protection threshold is not adjusted synchronously, leading to situations where the actual slippage limit is approaching or reached but protection is not triggered in time.

[0179] S112, When the cumulative number of slippages exceeds a preset threshold, or the cumulative slippage duration exceeds a preset duration threshold, output a coupling maintenance reminder message.

[0180] The preset number of slippages is preferably 5, and the preset duration is preferably 1 hour. The designed slippage life of coupling friction plates is typically several to a dozen times (depending on the friction pair material and design margin). When the cumulative slippage count reaches 5 times, the friction plate has undergone multiple cycles of sliding friction wear, and the remaining life is insufficient to support long-term safe operation, requiring maintenance and evaluation. A cumulative slippage duration of 1 hour means that the friction plate has operated under sliding friction conditions for a considerable period, and the cumulative heat input and wear have reached a level requiring inspection. Here, 1 hour refers to the total cumulative slippage time, not the duration of a single slippage, but the sum of multiple slippage durations.

[0181] When the wear and aging correction coefficient K w When the cumulative reduction reaches a certain level, the system will proactively alert maintenance personnel by outputting a maintenance reminder message to prevent wear and aging correction factor K from being affected. w Continuing to lower the protection threshold beyond a reasonable range will result in the protection threshold being too low. At the same time, it provides maintenance personnel with clear inspection opportunities and specific maintenance directions, which is conducive to timely detection of friction plate wear problems and taking remedial measures to prevent serious damage to the friction plate or sudden failure shutdown due to continuous operation.

[0182] The method described in this application embodiment is based entirely on the existing output information of the wind turbine (real-time high-speed shaft speed, real-time converter power, real-time converter torque, and nacelle temperature) for slippage identification. This data can be directly obtained from the existing sensors and monitoring and data acquisition systems of the wind turbine, without the need to add any dedicated sensors to the input side such as blades or rotor. This fundamentally avoids the hardware costs, installation costs, and subsequent maintenance costs associated with adding sensors. Furthermore, since no hardware modifications to existing wind turbines are required, on-site deployment is simple, the implementation cycle is short, and it is easier to promote and apply to existing units. This solves the problems of complex installation, high cost, and difficult maintenance associated with input load-based identification schemes mentioned in the background art.

[0183] By separately determining the instantaneous total load torque and the dynamic critical slippage torque, and using the ratio between the two as the slippage risk coefficient, slippage risk can be identified in advance when the actual load approaches but has not yet exceeded the bearing limit. The threshold R1 for determining the slippage warning state is less than 1, meaning that a warning and first-level protection action can be triggered even before the slippage risk coefficient reaches 1, allowing protection to be executed before slippage actually occurs. This fundamentally solves the deficiency of the speed comparison-based scheme mentioned in the background technology, which can only provide post-event protection after slippage occurs, realizing a shift from passive response to proactive prevention.

[0184] In this embodiment, the real-time torque of the converter and the real-time speed of the high-speed shaft are both collected from the high-speed shaft side. The signal source is located at the output end of the transmission chain and is directly related to the coupling, eliminating the need for transmission attenuation through multiple transmission components such as the impeller, main shaft, and gearbox. The torque change rate dT / dt is directly calculated based on the real-time torque of the converter, which can more quickly reflect the transient changes in the load borne by the coupling. This advantage solves the shortcomings of the input load-based schemes mentioned in the background art, which suffer from low recognition accuracy due to slow load changes at the input end and long signal transmission paths.

[0185] This application employs a three-tiered risk assessment system: safe state, warning state, and fault state, along with corresponding three-tiered progressive protection actions: no action, first-level power reduction protection, and second-level emergency shutdown protection. In the safe state, no intervention is implemented to ensure power generation efficiency; in the warning state, power is reduced to proactively avoid slippage and unnecessary shutdowns; and in the fault state, emergency shutdown is performed to ensure equipment safety. The progressive relationship between each level ensures that the strength of the protection strategy is strictly matched to the risk level, avoiding power generation losses caused by over-protection triggered by minor risks while ensuring that equipment safety is not compromised under severe risks.

[0186] By adaptively updating the temperature correction coefficient, the dynamic critical slippage torque can be adjusted in real time according to changes in engine room temperature, avoiding protection lag caused by the actual load-bearing capacity decreasing due to temperature rise and the protection threshold not being adjusted synchronously. Through adaptive updates of the wear and aging correction coefficient, the protection threshold can be dynamically reduced based on the cumulative number of slippages and the cumulative slippage duration, ensuring that the protection strategy always matches the actual wear state of the friction pads throughout the entire service life. Simultaneously, when the cumulative slippage reaches a dangerous threshold, a maintenance reminder is output, guiding maintenance personnel to intervene promptly, achieving an upgrade from periodic maintenance to condition-based preventative maintenance. The synergistic effect of these correction mechanisms addresses the inherent defect of fixed threshold protection schemes gradually failing due to environmental changes and component aging during long-term operation.

[0187] Reference Figure 2 This application embodiment also provides a wind turbine coupling slippage identification and protection device, including:

[0188] The acquisition module 201 is used to acquire the real-time speed of the high-speed shaft of the wind turbine, the real-time power of the converter, the real-time torque of the converter, and the nacelle temperature.

[0189] The calculation module 202 is used to determine the instantaneous total load torque and dynamic critical slip torque of the wind turbine based on the real-time speed of the high-speed shaft, the real-time power of the converter, the real-time torque of the converter, and the nacelle temperature, respectively.

[0190] The risk level classification module 203 is used to determine the slippage risk level of the coupling based on the instantaneous total load torque and the dynamic critical slippage torque.

[0191] The protection module 204 is used to perform corresponding coupling protection actions according to the coupling slippage risk level.

[0192] This application also provides a wind turbine generator set, including the aforementioned wind turbine generator set coupling slippage identification and protection device.

[0193] It should be understood that the application of this application is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims. Those skilled in the art can understand that implementing all or part of the processes of the above embodiments and making equivalent changes according to the claims of this application still fall within the scope of this application.

Claims

1. A method for identifying and protecting against slippage in wind turbine couplings, characterized in that, include: Obtain the real-time high-speed shaft speed, real-time converter power, real-time converter torque, and nacelle temperature of the wind turbine. The instantaneous total load torque and dynamic critical slippage torque of the wind turbine are determined based on the real-time speed of the high-speed shaft, the real-time power of the converter, the real-time torque of the converter, and the nacelle temperature, respectively. The slippage risk level of the coupling is determined based on the instantaneous total load torque and the dynamic critical slippage torque. Based on the slippage risk level of the coupling, the corresponding coupling protection action is executed.

2. The method for identifying and protecting wind turbine coupling slippage according to claim 1, characterized in that, The steps for determining the instantaneous total load torque and dynamic critical slippage torque of the wind turbine based on the real-time speed of the high-speed shaft, the real-time power of the converter, the real-time torque of the converter, and the nacelle temperature include: Calculate the steady-state load torque based on the real-time speed of the high-speed shaft and the real-time power of the converter; The rotational speed change rate is calculated based on the real-time rotational speed of the high-speed shaft, and the inertial impact torque is calculated based on the rotational speed change rate. Calculate the instantaneous total load torque based on the steady-state load torque and the inertial impact torque; The torque change rate is calculated based on the real-time torque of the converter, and the friction coefficient is dynamically corrected based on the torque change rate to obtain the dynamic friction coefficient. The dynamic critical slippage torque is calculated based on the dynamic friction coefficient and the cabin temperature.

3. The method for identifying and protecting wind turbine coupling slippage according to claim 1, characterized in that, The steps for determining the slippage risk level of the coupling based on the instantaneous total load torque and the dynamic critical slippage torque include: The ratio of the instantaneous total load torque to the dynamic critical slippage torque is calculated and used as the slippage risk coefficient. The slippage risk coefficient is compared with a preset risk threshold. When the slippage risk coefficient is less than the first preset threshold, the coupling is determined to be in a safe state; When the slippage risk coefficient is greater than or equal to the first preset threshold and less than the second preset threshold, the coupling is determined to be in a slippage warning state. When the slippage risk coefficient is greater than or equal to the second preset threshold, the coupling is determined to be in a slippage fault state. Wherein, the first preset threshold is less than the second preset threshold, and both the first preset threshold and the second preset threshold are positive numbers less than or equal to 1.

4. The method for identifying and protecting the slippage of a wind turbine coupling according to claim 1, characterized in that, Based on the slippage risk level of the coupling, the steps for performing the corresponding coupling protection action include: When the coupling is determined to be in a safe state, the current operating state of the wind turbine is maintained and no protection action is performed. When the coupling is determined to be in a slippage warning state, a first-level protection action is executed. The first-level protection action includes: sending a power reduction operation command to the wind turbine main control system, controlling the turbine to reduce the output power to the target power value at a preset power reduction rate, and continuously monitoring the slippage risk coefficient; if the slippage risk coefficient drops below the safe state threshold within a preset time period, the warning is lifted and the power is restored; if the slippage risk coefficient does not drop below the safe state threshold within the preset time period, the power reduction operation is maintained and monitoring continues. When the coupling is determined to be in a slippage fault state, a secondary protection action is executed. The secondary protection action includes: sending an emergency stop command to the wind turbine main control system, controlling the unit to execute the emergency stop procedure, cutting off power output, and recording the current operating data and slippage event log.

5. The method for identifying and protecting the slippage of a wind turbine coupling according to claim 4, characterized in that, When it is determined that the coupling is in a slippage warning state and no emergency stop has been executed, the method further includes: The cabin temperature is compared with a preset temperature threshold. When the cabin temperature is greater than the first preset temperature threshold, the temperature correction coefficient in the dynamic critical slip torque is reduced by a preset step size. When the cabin temperature is greater than the second preset temperature threshold, the temperature correction coefficient is further reduced by a preset step size, wherein the second preset temperature threshold is greater than the first preset temperature threshold. The dynamic critical slip torque is recalculated using the updated temperature correction coefficient, and the recalculated dynamic critical slip torque is used for subsequent slip risk level determination.

6. The method for identifying and protecting the slippage of a wind turbine coupling according to claim 4, characterized in that, The method further includes: Record slip events in a log, which includes the cumulative number of slips and the cumulative duration of slips; Based on the slippage event log, the wear and aging correction coefficient in the dynamic critical slippage torque is updated: wherein, for each increase in the cumulative slippage count, the wear and aging correction coefficient is reduced by one level according to a preset step size; and / or for each increase in the cumulative slippage duration by a preset duration, the wear and aging correction coefficient is reduced by one level according to a preset step size; The dynamic critical slippage torque is recalculated using the updated wear and aging correction coefficient, and the recalculated dynamic critical slippage torque is used for subsequent slippage risk level determination. When the cumulative number of slippages exceeds a preset threshold, or the cumulative slippage duration exceeds a preset duration threshold, a coupling maintenance reminder message is output.

7. The method for identifying and protecting wind turbine coupling slippage according to claim 2, characterized in that, The steps for calculating the steady-state load torque based on the real-time speed n of the high-speed shaft and the real-time power of the converter include: The real-time rotational speed of the high-speed shaft is time-differentized, and the rate of change of rotational speed dn / dt is calculated. Obtain the total rotational inertia J on the high-speed shaft side; The inertial impact moment Tinertia is calculated using the following formula: Where ω is the angular velocity and n is the real-time rotational speed of the high-speed shaft; The steps for calculating the instantaneous total load torque based on the steady-state load torque and the inertial impact torque include: Calculate the instantaneous total load torque T using the following formula. load : Among them, T steady For the steady-state load torque, T inertia The inertial impact torque; The steps of calculating the torque change rate based on the real-time torque of the converter, and dynamically correcting the friction coefficient based on the torque change rate to obtain the dynamic friction coefficient include: The real-time torque T of the converter is time-differentiated, and the torque change rate dT / dt is calculated. The static friction coefficient μ is determined based on the absolute value of the torque change rate dT / dt. s Dynamic attenuation correction is performed to obtain the dynamic friction coefficient μ. d : Where, μ s β is the static friction coefficient, and β is the friction material rate attenuation coefficient; The steps for calculating the dynamic critical slippage torque based on the dynamic friction coefficient and the cabin temperature include: Obtain the inherent structural parameters of the coupling, including the number of friction surfaces z and the total axial preload F of the friction plates. n and the average radius r of the friction surface m ; The correction factor for the coupling is obtained, the correction factor including the centrifugal correction factor K determined based on the real-time rotational speed. n The temperature correction factor Kt and the wear and aging correction factor K are determined based on the cabin temperature. w ; According to the dynamic friction coefficient μ d Number of friction surfaces z, total axial preload F of friction plates n and the average radius r of the friction surface m Centrifugal correction factor K n Temperature correction factor Kt and wear aging correction factor K w Calculate the dynamic critical slippage torque T slip_dynamic : 。 8. The method for identifying and protecting wind turbine coupling slippage according to claim 7, characterized in that, The centrifugal correction coefficient K n Determined according to the following formula: Where k1 is the centrifugal correction constant, with a value ranging from 0.12 to 0.18; n is the real-time rotational speed of the high-speed shaft; n e This refers to the rated speed of the high-speed shaft. When the cabin temperature is less than or equal to the first temperature threshold, the centrifugal speed correction coefficient K t The value is 1; When the cabin temperature is greater than the first temperature threshold and less than or equal to the second temperature threshold, the centrifugal speed correction coefficient K is... t Take the first correction value; When the cabin temperature is greater than the second temperature threshold, the centrifugal speed correction coefficient K... t Take the second correction value; Wherein, the first temperature threshold is less than the second temperature threshold, and the second correction value is less than the first correction value.

9. A wind turbine coupling slippage identification and protection device, characterized in that, include: The acquisition module is used to acquire the real-time high-speed shaft speed, real-time converter power, real-time converter torque, and nacelle temperature of the wind turbine. The calculation module is used to determine the instantaneous total load torque and dynamic critical slippage torque of the wind turbine based on the real-time speed of the high-speed shaft, the real-time power of the converter, the real-time torque of the converter, and the nacelle temperature, respectively. The risk level classification module is used to determine the slippage risk level of the coupling based on the instantaneous total load torque and the dynamic critical slippage torque. The protection module is used to perform corresponding coupling protection actions based on the coupling slippage risk level.

10. A wind turbine generator set, characterized in that, Includes the wind turbine coupling slippage identification and protection device as described in claim 9.

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