Emergency protection methods and devices for wind turbine blade clearance and wind turbine generator sets

Abstract

This application relates to the field of wind power generation technology, and provides a method, device, and wind turbine for emergency protection of wind turbine blade clearance. The method includes: determining the clearance deterioration rate based on clearance monitoring data; and triggering an emergency feathering action at the maximum pitch rate in response to the clearance deterioration rate meeting an emergency triggering condition. This application uses the clearance deterioration rate as a leading trend warning criterion, identifying and proactively intervening in deterioration trends before the absolute clearance falls below the safety threshold. It also overcomes the rate limitations of conventional shutdown logic, rapidly avoiding danger at the maximum pitch rate, significantly shortening the protection response time, and securing a critical time window for establishing a safe clearance margin, effectively reducing the probability of tower sweep accidents.

Description

Technical Field

[0001] This application relates to the field of wind power generation technology, and more specifically, to a method, device, and wind turbine generator set for emergency protection of wind turbine blade clearance. Background Technology

[0002] Currently, during operation, the blades of horizontal axis wind turbines undergo bending deformation in the flapping direction under aerodynamic loads. With the continuous increase in single-unit capacity, blade lengths have exceeded 100 meters, significantly enhancing blade flexibility. Under extreme wind conditions, sudden turbulence changes, excessive yaw errors, or lag in pitch control response, the flapping deformation of the blades towards the tower can increase dramatically, leading to a rapid decrease in the clearance between the blade tip and the tower. When the clearance falls below the design safety threshold, there is a serious risk of blade collision with the tower (i.e., tower sweep), which could result in blade breakage, tower damage, or even turbine collapse.

[0003] Regarding the monitoring and protection of wind turbine blade clearance, existing technologies mainly have the following types of solutions and shortcomings: The first type is the airspace monitoring and early warning scheme, which measures the airspace distance in real time using radar or cameras. When the airspace falls below the limit, it triggers reduced power operation or a regular shutdown. However, the response logic of this type of scheme is "monitoring - exceeding the limit - executing a regular shutdown". The pitch rate during the regular shutdown process is limited by the control parameters during normal operation (generally 4° / s to 8° / s). It takes several seconds to complete the full pitch stroke. Under extreme transient conditions where a sudden gust of wind causes a sharp reduction in airspace, the shutdown process at the regular pitch rate does not have enough time to establish a sufficient airspace safety margin before the blades sweep the tower.

[0004] The second category is load control schemes based on model prediction, which adjust the pitch angle in advance by establishing a wind turbine aeroelastic coupling simulation model and combining it with wind condition prediction. This type of scheme relies on accurate wind condition prediction and system modeling, and is limited by prediction accuracy and computational complexity, thus having limited response capability to transient small headroom caused by sudden turbulent impacts.

[0005] The third type is the safety chain hardware protection scheme, which directly triggers the pitch system to perform emergency feathering at the maximum pitch rate when serious faults such as overspeed or excessive vibration are triggered. However, the triggering conditions of the existing safety chain do not include the direct criterion of "insufficient clearance". It often needs to evolve into tower sweeping leading to excessive vibration or blade breakage leading to abnormal speed before it can be indirectly triggered, and the protection action lags behind the accident evolution process.

[0006] In summary, existing technologies for safety protection under sudden low clearance conditions have several drawbacks. The conventional shutdown pitch rate is insufficient to cope with the transient risk of a sharp decrease in clearance. There is a lack of control logic that directly links clearance monitoring signals with an emergency pitch rapid response mechanism. Furthermore, the existing safety chain system does not treat clearance as an independent trigger condition and cannot proactively intervene before tower sweep occurs. These issues result in delayed response under sudden low clearance conditions, making tower sweep accidents highly likely. Summary of the Invention

[0007] The purpose of this application is to provide a method, device and wind turbine generator set for emergency protection of wind turbine blade clearance. Based on the rate of change of clearance degradation, the deterioration trend is identified in advance and an emergency feathering action is directly triggered at the maximum pitch rate of the system, so as to realize the ultra-fast anti-collision protection that actively establishes a safe clearance margin before the blade collides with the tower.

[0008] Firstly, this application provides an emergency protection method for the airspace clearance of wind turbine blades, comprising: Based on airspace monitoring data, determine the rate of change in airspace deterioration; In response to the airspace deterioration rate meeting the emergency triggering condition, an emergency feathering action is triggered at the maximum pitch rate.

[0009] In an optional implementation, determining the rate of change in airspace deterioration based on airspace monitoring data includes: The rate of change of airspace deterioration is determined based on the current airspace distance and the historical airspace sequence.

[0010] In an optional implementation, determining the rate of change of airspace deterioration based on the current airspace distance and the historical airspace sequence includes: Extract the airspace distance values ​​from the previous N sampling periods from the historical airspace sequence, where N is a positive integer; Calculate the difference between the clearance distance value before the previous N sampling periods and the clearance distance value at the current moment; Based on the ratio of the difference to the corresponding time window, the net airspace deterioration rate is determined, where the time window is the total duration corresponding to N sampling periods; The airspace deterioration rate represents the rate at which the airspace distance decreases per unit time. When the difference is positive, it indicates that the airspace distance is decreasing and the airspace deterioration rate is positive, indicating that the airspace is deteriorating. When the difference is negative or zero, it indicates that the airspace distance is increasing or remaining unchanged and the airspace deterioration rate is negative or zero, indicating that the airspace is in a safe trend. The emergency triggering condition includes the airspace deterioration rate being greater than a preset airspace change rate safety threshold.

[0011] In an optional implementation, triggering an emergency feathering action at the maximum pitch rate includes: Drive the blades to the feathering position at the maximum permissible pitch rate that covers the normal pitch rate limit.

[0012] In an optional implementation, the maximum permissible pitch rate is greater than 8° / s; The normal operating pitch rate is limited to 4° / s to 8° / s; Emergency feathering actions that trigger at maximum pitch rate also include: Send an emergency pitch control command to the pitch control system. The emergency pitch command includes a target pitch angle, a pitch rate command, and a priority identifier. Wherein, the target pitch angle is the feathering position angle, the pitch rate command is executed at the maximum permissible pitch rate, and the priority identifier is the emergency protection priority, which is higher than the normal power control pitch command; The pitch angle corresponding to the feathering position is around 90°, which ensures that the aerodynamic load on the blades is quickly removed and the flapping deformation of the blades towards the tower is quickly restored. Based on the angular difference between the current pitch angle position and the target feathering position, and the maximum permissible pitch rate, calculate the expected pitch action duration.

[0013] In an optional implementation, the method further includes: In response to the current airspace distance being less than the absolute safety threshold, an emergency feathering maneuver is directly triggered at the maximum pitch rate.

[0014] In an optional implementation, the method further includes, prior to triggering an emergency feathering maneuver executed at the maximum pitch rate: The persistence of the airspace deterioration rate and the unit's operating status were cross-checked to rule out false triggering.

[0015] In an optional implementation, the method further includes, after the emergency feathering maneuver performed at the maximum pitch rate, the following steps: Trigger the generator to disconnect from the grid or reduce it to idle speed to prevent runaway; Record complete event data that triggers the emergency feathering action. The complete event data includes the trigger time, the airspace sequence before the trigger, wind speed conditions, operating status parameters, and pitch execution process data, for subsequent fault analysis and control strategy optimization. Based on the number and severity of emergency pitch triggers, it is determined whether the unit can be allowed to automatically reset and restart, or whether manual on-site inspection and confirmation are required before it can be reconnected to the grid. The determination of whether to allow the unit to automatically reset and restart includes: If the number of emergency pitch triggers does not exceed the preset threshold and the severity does not exceed the preset severity threshold, the unit is allowed to automatically reset and restart. If the number of emergency pitch triggers exceeds the preset threshold, or the severity exceeds the preset severity threshold, manual on-site inspection and confirmation are required before the system can be reconnected to the grid.

[0016] Secondly, this application provides an emergency protection device for the airspace clearance of wind turbine blades, comprising: The processing module is used to determine the rate of change of airspace deterioration based on airspace monitoring data; The control module is used to trigger an emergency feathering action at the maximum pitch rate in response to the airspace deterioration rate meeting the emergency triggering condition.

[0017] Thirdly, this application provides a wind turbine generator set, including blades, a tower, and an emergency protection device for blade clearance as described in the foregoing embodiments.

[0018] Beneficial effects: This application directly links the clearance monitoring signal with the maximum pitch rate. Under sudden low clearance conditions, emergency feathering is performed at the maximum rate allowed by the pitch system hardware, which breaks through the limitation on pitch rate in normal operation logic. This shortens the response time compared to conventional shutdown methods and provides a critical time window for establishing a safe clearance margin for the blades.

[0019] By introducing the rate of change in airspace deterioration as a prerequisite judgment condition, it is possible to identify the rapid deterioration of transient trends and take the initiative to intervene before the absolute airspace falls below the safety threshold. This shifts the triggering time for safety protection from reactive remediation after a tower sweep to proactive prevention before the tower sweep occurs, effectively reducing the probability of tower sweep accidents.

[0020] This application incorporates multiple judgment steps, including continuous confirmation of the net airspace change rate and cross-verification of the unit's operating status. This effectively eliminates false triggering caused by instantaneous noise interference from sensors, ensuring that emergency pitch control is only triggered under real sudden risk conditions, thus avoiding unnecessary power generation losses.

[0021] By setting an absolute safety threshold to trigger a graded emergency pitch strategy and a rate-of-change trend trigger, corresponding rapid response mechanisms are matched under different risk conditions. This reduces the impact load on the pitch drive system and blade structure while ensuring airspace safety, and extends the life of key components.

[0022] This application provides a complete record of the data from the entire process of triggering emergency pitch control, providing detailed data support for subsequent analysis of the causes of sudden low airspace, optimization of control strategies, and assessment of unit safety. Attached Figure Description

[0023] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments of this application will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 A schematic flowchart of an emergency protection method for wind turbine blade clearance provided in this application embodiment; Figure 2 A schematic diagram of an emergency protection device for the air clearance of a wind turbine blade provided in this application embodiment; Figure 3 This is a schematic diagram of a wind turbine generator set provided in an embodiment of this application. Detailed Implementation

[0025] The technical solutions in the embodiments of this application will now be described with reference to the accompanying drawings.

[0026] like Figure 1 As shown, this embodiment provides an emergency protection method for wind turbine blade clearance. This method constructs an overall control framework combining proactive trend warning and rapid disaster avoidance response, aiming to solve the response lag problem caused by relying solely on absolute clearance thresholds to trigger conventional rate shutdowns in existing technologies. The method of this embodiment mainly includes the following steps: Step S110: Determine the rate of change in airspace deterioration based on airspace monitoring data.

[0027] Specifically, air clearance monitoring data refers to the distance information between the blade tip and the tower, which is obtained in real time through distance sensors installed on the unit.

[0028] The "rate of change in clearance degradation" referred to in this application embodiment refers to the rate of decrease in clearance distance per unit time, reflecting the speed of dynamic deterioration of blade deformation towards the tower. In this step, the reason for using the "rate of change" rather than the "absolute value" as the core criterion for triggering emergency protection is that blade flexible deformation under sudden gusts or extreme turbulence impacts exhibits extremely rapid transient changes. If protection is triggered solely based on whether the absolute clearance distance falls below the safety threshold, since an absolute value exceeding the limit often indicates that the deterioration trend has already developed to an extremely dangerous stage, initiating protection at this point leaves very limited time for the unit to establish a safety margin, easily leading to blade-tower-sweeping accidents. By extracting this dynamic trend feature of the rate of change in clearance degradation, the transient deterioration trend of rapidly decreasing clearance can be identified before the absolute clearance distance falls below the safety threshold. This shifts the triggering time for safety protection from a delayed remedy after an absolute value exceeds the limit to an early prevention measure when the deterioration trend first appears, providing crucial time margin for subsequent rapid disaster avoidance responses.

[0029] It should be understood that there are various methods for calculating and extracting the net airspace deterioration change rate. This embodiment only provides the most basic trend warning logic. The specific time-series calculation logic and algorithm formula of the change rate will be elaborated in detail in subsequent advanced embodiments.

[0030] Step S120: In response to the airspace deterioration rate meeting the emergency triggering condition, an emergency feathering action is triggered at the maximum pitch rate.

[0031] Specifically, emergency triggering conditions refer to pre-set threshold conditions used to determine whether the trend of deteriorating airspace has reached the danger limit for immediate intervention.

[0032] When the calculated rate of change in airspace deterioration meets the emergency triggering condition, it indicates that the airspace is decreasing rapidly at a dangerous rate, posing an extremely high risk of tower sweeping. At this point, an emergency feathering action should be triggered immediately.

[0033] The "maximum pitch rate" referred to in this application's embodiments refers to the highest pitch speed that the pitch drive system can achieve under the limits of its hardware and electrical capabilities, which is significantly higher than the pitch rate limit allowed in normal operating logic. The reason for exceeding the conventional rate limit and using the maximum pitch rate to perform emergency feathering at this time is that under transient conditions of rapidly deteriorating clearance, the conventional shutdown pitch rate is limited by normal operating control parameters, and completing the full stroke of feathering takes several seconds. This conventional speed response is simply insufficient to quickly remove the aerodynamic load before the blades sweep the tower and to promote the recovery of the blade flapping deformation. Executing emergency feathering at the maximum rate allowed by the pitch system hardware is necessary to drive the blades to the feathering position in the shortest possible time, rapidly remove the aerodynamic load, and allow the blade flapping deformation towards the tower to recover extremely quickly, thereby achieving rapid hazard avoidance.

[0034] It should be understood that this embodiment does not specify the exact range of the maximum pitch rate or the control command reconfiguration logic that covers the conventional rate limit. The specific parameter mapping and hardware binding logic will be further elaborated in subsequent advanced embodiments.

[0035] Through the above steps S110 and S120, the change rate trend warning provides a triggering opportunity for the rapid response, and the rapid response provides substantial risk avoidance capability for the trend warning. Together, they proactively establish a critical safety clearance margin before the blade collides with the tower, fundamentally overcoming the core pain point of delayed conventional shutdown response.

[0036] In some embodiments, determining the rate of change of airspace deterioration based on airspace monitoring data includes: determining the rate of change of airspace deterioration based on the current airspace distance and the historical airspace sequence.

[0037] The historical airspace sequence refers to the time series of airspace distance values ​​acquired over multiple consecutive sampling periods in the past. The reason for introducing the historical airspace sequence instead of relying solely on instantaneous values ​​at a single moment for trend judgment is that in actual wind field environments, airspace monitoring sensors are affected by gusts, blade passage effects, or electromagnetic interference, and the instantaneous data they collect is often accompanied by high-frequency noise fluctuations. Judging a deteriorating trend based solely on a single instantaneous data point is highly susceptible to misjudgment due to noise interference.

[0038] By combining the current clearance distance with a continuous historical clearance sequence, the macroscopic trend characteristics of clearance distance evolution can be extracted from the time-series dimension, effectively filtering out or smoothing instantaneous interference noise, so that the determined rate of deterioration truly reflects the physical dynamics of blade flapping deformation, rather than the illusion of sensor measurement noise.

[0039] Furthermore, determining the airspace deterioration rate based on the current airspace distance and the historical airspace sequence includes: extracting the airspace distance values ​​from the previous N sampling periods from the historical airspace sequence, where N is a positive integer; calculating the difference between the airspace distance values ​​from the previous N sampling periods and the airspace distance value at the current moment; and determining the airspace deterioration rate based on the ratio of the difference to the corresponding time window, where the time window is the total duration corresponding to the N sampling periods.

[0040] Specifically, this embodiment provides a preferred calculation formula: ; in The current rate of change in net airspace deterioration. This represents the current clearance distance. This represents the clearance distance value before the previous N sampling periods. The duration of a single sampling period. This is the total duration of the corresponding time window.

[0041] Among them, the rate of change of airspace deterioration represents the rate at which the airspace distance decreases per unit time. When the difference is positive, that is... Greater than This indicates that the clearance distance is decreasing. A positive rate of change in clearance deterioration indicates that the clearance is worsening, and the blades are approaching the tower in a dangerous flaring deformation. When the difference is negative or zero, i.e. Less than or equal to This indicates that the clearance distance is increasing or remaining constant. A negative or zero rate of change in clearance indicates that the clearance is trending towards safety, and the blades are moving away from the tower or maintaining a stable distance. The emergency trigger condition includes the rate of change in clearance exceeding a preset safe threshold for the rate of change in clearance.

[0042] Regarding the impact of the value of N, N determines the length of the time window used to extract trend features. For example, when the sampling frequency is 20Hz, if N is between 5 and 10, the corresponding time window is 0.25 to 0.5 seconds. This window range is sufficient to cover several sampling periods to smooth high-frequency noise, and short enough to ensure sensitivity in capturing sudden deterioration trends. It should be understood that the specific value of N should not be limited to this range; it can be adaptively adjusted according to the flexibility characteristics of different turbine blades and the sampling capabilities of the control system.

[0043] At the defense depth level, in addition to using the aforementioned difference-to-time-window ratio algorithm, similar methods such as the sliding window average slope method and the least squares fitting slope method can also be used to determine the rate of change of airspace deterioration. The sliding window average slope method extracts the trend by calculating the average slope of adjacent sampling points within a sliding window of the historical sequence; the least squares fitting slope method uses linear regression to fit the historical sequence, taking the slope of the fitted line as the rate of change. These equivalent methods also utilize the core logic of extracting trends from time-series historical data and can all achieve the effect of resisting instantaneous interference. It is particularly important to point out why a single instantaneous difference (i.e., N=1, only calculating the difference between the previous sampling period and the current period) cannot be selected. A single instantaneous difference essentially only reflects the local fluctuation between two very close moments, and its anti-interference ability is extremely poor. Once the sensor experiences jump noise in a certain sampling period, the instantaneous difference will produce a drastic change, which can easily trigger false emergency protection commands, leading to frequent false shutdowns of the unit and resulting in power generation losses. By introducing time series containing multiple historical sampling points for comprehensive trend extraction, a reliable anti-interference defense depth is established while ensuring response sensitivity, ensuring that the judgment of emergency triggering conditions is based on real physical deterioration trends rather than noise artifacts.

[0044] In some embodiments, triggering an emergency feathering action at the maximum pitch rate includes driving the blades to the feathering position at the maximum permissible pitch rate that covers the normal pitch rate limit.

[0045] The normal operating pitch rate limit refers to the upper limit set by the main control system for the pitch rate during normal power generation, power regulation, or routine shutdown, for purposes such as protecting the pitch drive motor, reducing mechanical shock, and maintaining aerodynamic stability. This limit is typically between 4° / s and 8° / s. The maximum permissible pitch rate referred to in this application, however, is the highest pitch speed that the pitch drive system can maintain for a short period under hardware boundary conditions such as full-load backup power output, motor overload capacity, and mechanical transmission limits. This maximum permissible pitch rate is greater than 8° / s, and can exemplarily reach 10° / s to 15° / s or higher. The reason for using the maximum permissible pitch rate, which covers the normal operating pitch rate limit, is that under extreme transient conditions such as sudden small clearance, the conventional 4° / s to 8° / s rate limit is a compromise based on the unit's lifespan and steady-state operation design, and it is fundamentally unable to complete the aerodynamic load removal within the extremely short time window before blade sweep. Only by breaking through this steady-state compromise and directly utilizing the hardware's limits can a sufficient safety margin be established in a life-or-death moment.

[0046] Furthermore, triggering an emergency feathering action at the maximum pitch rate also includes sending an emergency pitch control command to the pitch control system, the emergency pitch command including the target pitch angle, pitch rate command and priority indicator.

[0047] Specifically, under normal operating conditions, the pitch control system receives normal power control pitch commands from the main control power regulation loop, which have relatively low priority and are rate-limited. When emergency protection is triggered, the main control system or an independent safety controller reconstructs the command architecture, generating an emergency pitch command with an emergency protection priority identifier. This emergency protection priority is higher than the normal power control pitch command and has absolute preemption rights in the pitch control system's command queue. After parsing this priority identifier, the pitch control system immediately suspends or discards the currently executing normal power control pitch command, forcibly bypassing the normal rate limit lock, and drives the blades at the maximum permissible pitch rate specified in the command. The target pitch angle is the feathering position angle, which corresponds to a pitch angle around 90°, ensuring rapid removal of aerodynamic loads on the blades and rapid recovery of blade flapping deformation towards the tower.

[0048] It should be understood that the feathering position angle is typically set between 87° and 91°, with the specific value depending on the aerodynamic design of different units. The key is to achieve rapid aerodynamic load removal; 90° should not be interpreted as an absolute value. Simultaneously, based on the angle difference between the current pitch angle and the target feathering position, as well as the maximum permissible pitch rate, the expected duration of the pitch maneuver is calculated. This duration calculation is used not only to estimate the completion time of feathering but also to synchronously trigger subsequent actions such as generator disconnection in terms of timing logic, ensuring a closed-loop timing sequence for the entire disaster avoidance process.

[0049] To more clearly illustrate why conventional speeds of 8° / s and below are not feasible, an off-grid comparison is used for demonstration. Assume a 100-meter-class flexible blade turbine is operating at its rated speed. The current pitch angle is 80°, and the target feathering position is 90°. The required pitch stroke is 10°. If the upper limit of the conventional speed of 8° / s is selected for emergency feathering, the time required to complete this 10° stroke is 1.25 seconds. However, under extreme gust turbulence, the blade's flapping deformation rate towards the tower is extremely rapid, with the clearance deterioration rate potentially reaching several meters per second. A 1.25-second response delay means that the blade tip will continue to approach the tower by several meters during this time. On a flexible blade turbine with already limited initial clearance margin, this 1.25-second lag will directly lead to blade-to-tower sweep accidents, causing catastrophic consequences such as blade breakage or even tower collapse. In contrast, if an emergency feathering operation is performed at the maximum permissible pitch rate of 15° / s proposed in this embodiment, the time required to complete the same 10° stroke is only 0.67 seconds. Compared to 1.25 seconds, the extremely rapid response of 0.67 seconds reduces the pitch action time by nearly half. This gained 0.58 seconds of time margin is sufficient to quickly remove the aerodynamic load before the blades sweep the tower, causing the blades to flap and deform rapidly and rebound, thereby avoiding a collision. This comparative example clearly demonstrates that conventional rates of 8° / s and below are not selectable under sudden small clearance conditions, and only a maximum permissible pitch rate greater than 8° / s can achieve true rapid avoidance. It should be understood that the above-mentioned 10° stroke, 8° / s, 15° / s, and the calculated 1.25 seconds and 0.67 seconds are only specific examples given to demonstrate that conventional rates are not selectable. The actual stroke and rate in operation may vary due to different unit designs, but the core mechanism of breaking through the conventional rate limit to gain time margin remains unchanged.

[0050] Furthermore, the communication timing logic of emergency pitch control commands is equally crucial. When a command is sent, the target pitch angle, pitch rate command, and priority identifier are typically packaged in the same communication frame and transmitted in parallel to the pitch control system via a high-speed fieldbus or hardwired signals. This ensures the real-time and complete arrival of the command and avoids timing errors or delays caused by framed transmission. The above description is illustrative only and not restrictive. Any parameter mapping and execution methods that bypass conventional rate limitations and drive the blades to feather rapidly through command reconfiguration logic should fall within the scope of this application.

[0051] In some embodiments, the method further includes: in response to the current clearance distance being less than an absolute safety threshold, directly triggering an emergency feathering maneuver performed at the maximum pitch rate.

[0052] Here, the current clearance distance refers to the absolute physical distance between the blade tip and the tower casing, measured in real time at the current moment, i.e., the aforementioned... .

[0053] The absolute safety threshold refers to the minimum permissible safe distance between the blade tip and the tower. If the distance is below this value, it means that a physical collision between the blade and the tower is imminent, and there is an extremely high risk of immediate tower sweep.

[0054] It should be understood that the specific value of the absolute safety threshold is not a fixed number of meters, but is determined comprehensively based on the structural clearance design between the wind turbine tower and blades, the flexible deformation characteristics of the blades, and safety margin requirements. Different capacity turbines and blades of different lengths have different tower wall thicknesses and maximum allowable flapping deformations. Therefore, the absolute safety threshold needs to be determined during the turbine design phase through aeroelastic coupling analysis and structural strength verification. It is typically set as the minimum clearance between the blade tip and the tower when the blade is stationary, minus a certain percentage of the safety margin.

[0055] The reason for setting up a direct trigger logic for absolute clearance exceeding the limit in addition to the rate of change trend warning is that this constitutes a double-insurance mechanism for the rate of change warning. In extreme operating conditions, there exists a dangerous scenario with extremely rapid changes, such as a sudden impact from an extreme gust of wind or a brief loss or jump in sensor data, causing a precipitous drop in clearance distance in a very short instant. In such a rapidly changing scenario, the system may not have enough time to accumulate a sufficiently long historical clearance sequence to calculate a reliable rate of deterioration, or the rate of change calculation may miss a detection due to missing sequences. In this case, the rate of change trend warning may not be able to capture the danger signal in time, while the absolute clearance threshold serves as the last physical line of defense. Regardless of whether the rate of change warning has been triggered, once the current clearance distance falls below the absolute safety threshold, it indicates that the blades have entered the red line zone for tower sweeping, and immediate action is taken.

[0056] Therefore, when When the absolute safety threshold is below, the control logic in this embodiment does not require intermediate judgment steps such as rate of change calculation and continuity confirmation. Instead, it directly triggers an emergency feathering action executed at the maximum pitch rate. In other words, when the absolute clearance has fallen below the physical safety threshold, the time window for the crew to avoid a collision has been compressed to the millisecond level. Any additional calculation, confirmation, or delay could lead to catastrophic consequences. At this point, the decision-making chain is compressed to the extreme, directly and hard-linking "detecting exceeding the limit" and "rapid avoidance," achieving zero-latency bottom-line protection.

[0057] It should be understood that although this embodiment focuses on describing the logic of direct triggering by the absolute clearance threshold, in actual control systems, absolute threshold triggering and rate of change triggering are usually monitored in parallel and judged independently. They converge at the execution end of triggering an emergency feathering maneuver executed at the maximum pitch rate, both pointing to the same rapid risk avoidance response mechanism. This dual-insurance mechanism design ensures both the proactiveness of trend warning and the absolute reliability of bottom-line triggering.

[0058] In some embodiments, before triggering an emergency feathering action at the maximum pitch rate, the method further includes: cross-checking the persistence of the airspace deterioration rate and the unit operating status to rule out false triggering.

[0059] In actual wind farm operating environments, the clearance monitoring sensors are susceptible to transient noise fluctuations due to gusts, electromagnetic interference, or blade passage effects. If an emergency avoidance response is triggered immediately based solely on a single momentary exceedance of the rate of change, false signals can easily lead to frequent erroneous unit shutdowns, causing unnecessary power generation losses and mechanical impacts on the pitch drive system. Therefore, a false trigger exclusion mechanism is introduced before executing emergency avoidance to ensure that emergency protection actions are only triggered under genuine, sudden risk conditions.

[0060] Specifically, the continuous confirmation of the rate of change of airspace deterioration includes: continuously monitoring the rate of change for the next M sampling periods to be greater than the threshold, where M is a positive integer.

[0061] For example, when the sampling frequency is 20Hz, M takes the value of 3 to 5, corresponding to a confirmation time window of 0.15 to 0.25 seconds. Within this window, the system does not immediately execute emergency feathering, but continuously observes whether the deterioration trend is consistent. If the net clearance deterioration rate calculated for the subsequent M sampling cycles is consistently greater than the preset net clearance change rate safety threshold, then the rapid net clearance deterioration trend is confirmed to be consistent, rather than an accidental exceedance caused by instantaneous noise interference from the sensor. Regarding the value of M, M should not be too large. For example, if M exceeds 10, the corresponding confirmation delay will exceed 0.5 seconds. In the transient condition of rapidly deteriorating net clearance, this delay will severely compress the time margin for subsequent rapid avoidance, which may lead to missing the best intervention opportunity and causing tower sweep. At the same time, M should not be 1 either. If M is only 1, it is essentially still a confirmation of a single instantaneous data, which cannot rule out accidental noise jumps and is very likely to cause false triggering. Therefore, M of 3 to 5 is the optimal balance point between anti-interference reliability and avoidance timeliness.

[0062] Furthermore, the cross-confirmation of the unit's operating status includes the following specific sub-steps: First, determine whether the unit is in the shutdown process.

[0063] Specifically, the current pitch angle and pitch rate are obtained. If the pitch angle is moving in the feathering direction and the pitch rate is not zero, it indicates that the unit is in the process of normal shutdown or fault shutdown. At this time, there is no need to trigger the emergency pitch command again. The existing shutdown logic can be maintained to avoid redundant impact on the pitch system.

[0064] Secondly, determine whether the wind speed and turbulence intensity exceed the limit.

[0065] Specifically, the wind speed sequence for the most recent minute is obtained using an anemometer, and the ratio of the standard deviation to the average wind speed is calculated as an indicator of turbulence intensity. If this turbulence intensity exceeds a preset threshold, it confirms that the current sudden narrow headroom is caused by real physical deterioration due to extreme turbulence impact, rather than a false signal from the sensor, thus further confirming the necessity of triggering emergency intervention.

[0066] At the defense depth level, cross-confirmation can also include similar methods such as evidence of excessive nacelle vibration acceleration and excessive yaw error. When the blades undergo rapid flapping deformation towards the tower, the top of the tower and the nacelle usually experience significant dynamic load impacts, leading to an abnormal increase in the amplitude of nacelle vibration acceleration. Simultaneously, extreme gusts are often accompanied by sudden changes in wind direction, resulting in a sharp increase in yaw error. Therefore, both excessive nacelle vibration acceleration and excessive yaw error can serve as physical evidence of a rapidly deteriorating airspace. These equivalent methods, from different dimensions of physical quantities, confirm the same deteriorating trend, further solidifying the reliability of the trigger. It is particularly important to point out why relying solely on a single sensor signal is not advisable. Single sensor signals, whether from airspace radar, anemometers, or accelerometers, each have their own measurement blind spots and failure modes. For example, airspace radar may malfunction due to electromagnetic interference, anemometers may fail due to icing or obstruction, and accelerometers may drift due to loose installation. If an abnormality from a single signal source triggers an emergency shutdown, a malfunction or disturbance to that sensor itself could directly lead to system malfunctions. Only through multi-dimensional, multi-sensor cross-verification, forming a composite judgment logic, can false triggers caused by single sensor failure or noise be effectively eliminated, ensuring the absolute reliability of emergency protection actions.

[0067] This embodiment, through the coordinated cooperation of continuous confirmation and cross-confirmation of unit operating status, establishes a solid anti-interference defense depth while ensuring the timeliness of the rapid risk avoidance response. It effectively eliminates false triggering caused by false signals, ensuring that emergency feathering is only triggered under real sudden risk conditions, thus balancing the proactive nature of safety protection with the stability of unit operation.

[0068] In some embodiments, after an emergency feathering action is performed at the maximum pitch rate, the method further includes: triggering the generator to disconnect from the grid or reduce to idle speed to prevent overspeed; recording complete event data of the event that triggered the emergency feathering action, the complete event data including the trigger time, the clearance sequence before the trigger, wind speed conditions, operating status parameters, and pitch execution process data, for subsequent fault analysis and control strategy optimization; and determining, based on the number and severity of emergency pitch triggers, whether the unit can be automatically reset and restarted, or whether manual on-site inspection and confirmation are required before it can be reconnected to the grid.

[0069] Specifically, once the blades have been driven to the feathering position at maximum pitch rate, although the aerodynamic load has been significantly reduced and the clearance has returned to a safe range, the unit is still in a state of continuous high-speed rotational mechanical inertia. If the generator is not immediately disconnected from the grid, the unit may still maintain a high speed due to inertia the moment it loses aerodynamic driving force, and may even face the danger of overspeeding under the continuous action of external gusts. Therefore, synchronously triggering the generator to disconnect from the grid or reduce to idle speed disconnects the electrical load and actively consumes mechanical kinetic energy, ensuring that the unit speed quickly drops to the safe idle range and completely eliminating the risk of overspeeding.

[0070] At the same time, it can record complete event data that triggers emergency feathering maneuvers with high precision.

[0071] Among these, the trigger time serves as the absolute time reference for anchoring the event; the pre-trigger clearance sequence fully preserves the transient waveform characteristics of the rapidly deteriorating clearance, providing the core basis for analyzing the causes of sudden low clearance; wind speed conditions record the sudden gusts or turbulent impact environment at the time; operating status parameters, including the pitch angle, generator speed, and yaw error, are used to reconstruct the dynamic response background of the unit before triggering; and pitch execution process data records the actual pitch trajectory and rate response curve from the issuance of the command to the blade reaching the feathering position. This data not only provides data support under real-world conditions for subsequent fault analysis to trace the root cause of tower sweep risks but also enables future threshold settings and confirmation logic to be adaptively corrected based on historical data.

[0072] Furthermore, based on the number and severity of emergency pitch triggers, it is determined whether the unit can automatically reset and restart, or whether manual on-site inspection and confirmation are required before it can be reconnected to the grid. The determination of whether the unit can automatically reset and restart includes: if the number of emergency pitch triggers does not exceed a preset threshold and the severity does not exceed a preset severity threshold, the unit can automatically reset and restart; if the number of emergency pitch triggers exceeds a preset threshold or the severity exceeds a preset severity threshold, manual on-site inspection and confirmation are required before it can be reconnected to the grid.

[0073] The reason why automatic reset and restart of the unit cannot be unconditionally allowed is that under conditions of repeated impact from extreme turbulence or potential structural defects in the unit, airspace deterioration may occur frequently. If automatic reset and grid connection are unconditionally enabled after each trigger, the unit will be trapped in a cycle of "triggering emergency feathering - automatic reset and grid connection - encountering gusts again and triggering emergency feathering." This high-frequency repeated triggering will not only cause severe cumulative impact loads on the pitch drive motor, battery, and mechanical transmission mechanism, accelerating fatigue of key components and even leading to hardware damage, but also generate huge aerodynamic and mechanical transient loads during each high-speed feathering and grid disconnection process, causing irreversible damage to the lifespan of the blades and tower structure. Therefore, the frequency of automatic reset is limited by setting a trigger number threshold. When the frequency exceeds the limit, manual inspection is forced to eliminate potential equipment hazards.

[0074] Conversely, the reason why mandatory manual on-site inspections cannot be enforced before grid reconnection is that in actual wind farms, a significant portion of sudden minor clearing events are incidental events caused by brief extreme gusts or instantaneous turbulence. Once these incidental conditions pass and wind conditions stabilize, the turbines are already in a completely safe state. If manual on-site inspections and resets are mandatory for all such minor incidents, given that wind farms are often located in remote areas and turbines are widely distributed, it would take maintenance personnel several hours or even days to reach the site. This would result in prolonged shutdowns pending inspections even when safety conditions are met, causing unnecessary and significant power generation losses and severely impacting the economic benefits of the wind farm. Therefore, for incidental events that occur very infrequently and are of minor severity, allowing the turbines to automatically reset and restart after the system self-checks and confirms safety can maximize power generation recovery while relying on a threshold to prevent potential problems from escalating.

[0075] It should be understood that the severity threshold can be quantified based on parameters such as the peak rate of change in airspace deterioration at the time of triggering, the depth at which the absolute airspace distance falls below the safety baseline, or the maximum mechanical impact load during pitch control. Different units can set different quantification standards based on their structural strength and control strategies. The preset number of triggers threshold is usually set to 1 to 3 times, meaning that if the number of consecutive triggers exceeds this number within a single operating cycle, the automatic reset function will be locked. The specific value needs to be comprehensively calibrated in conjunction with the wind farm meteorological characteristics and the unit's hardware impact resistance.

[0076] like Figure 2 As shown, this embodiment provides an emergency protection device 200 for the airspace clearance of wind turbine blades. This device 200 is a hardware architecture mapping of the aforementioned method embodiments, designed to ensure the reliable execution of the core logic of proactive trend warning and rapid risk avoidance response in the physical controller through specific modular functional divisions. The device 200 mainly includes a processing module 201 and a control module 202.

[0077] Processing module 201 is used to determine the rate of change of airspace deterioration based on airspace monitoring data.

[0078] Specifically, the processing module 201 undertakes the core tasks of trend identification and data calculation in the method flow. It receives raw distance signals from airspace monitoring sensors (such as millimeter-wave radar, lidar, or visual ranging systems), and extracts the rate of deterioration, representing the rate of decrease in airspace distance per unit time, through time-series analysis of the current airspace distance and historical airspace sequences. The processing module not only performs basic difference and time window ratio calculations, but also integrates anti-interference algorithms such as the sliding window average slope method or the least squares method for fitting slopes to filter out instantaneous sensor noise and ensure that the output rate of deterioration truly reflects the physical dynamics of blade flapping deformation. It should be understood that, in terms of hardware implementation, the processing module can be a dedicated digital signal processor independent of the wind turbine main control system, specifically responsible for filtering and trend extraction of high-frequency airspace data; or it can be a software function block integrated within the wind turbine main control PLC, using the PLC's computing resources to complete the above calculation logic, as long as it has the function of determining the rate of deterioration of airspace based on airspace monitoring data. This embodiment does not limit its specific hardware model or physical carrier form.

[0079] Control module 202 is configured to trigger an emergency feathering action at the maximum pitch rate in response to the airspace deterioration rate meeting the emergency triggering condition.

[0080] Specifically, the control module 202 is responsible for decision-making and command reconfiguration for rapid emergency response. When it receives the deterioration rate of change signal from the processing module and determines that the rate of change exceeds the preset safety threshold for the rate of change of clearance, the control module immediately bypasses the rate limit of the normal operating power regulation loop and generates an emergency pitch command with an emergency protection priority indicator. This command includes the target feathering angle and the maximum permissible pitch rate, and is transmitted in parallel to the pitch control system via a high-speed fieldbus or hardwired signal, forcing the pitch drive system to perform feathering at the hardware limit rate. It should also be understood that the control module has a high degree of flexibility in its hardware implementation. In a preferred architecture, the control module can be integrated into the wind turbine's main control PLC, running as the highest-priority safety protection thread within the main control system. This facilitates cross-confirmation and coordination with other normal control logic of the unit. In a more independent and reliable architecture, the control module can be an independent safety controller. This safety controller runs in parallel with the main control PLC, and even in the event of a failure or crash in the main control PLC, it can still rely on an independent backup power supply and hard-wired signal channels to directly trigger the pitch system to perform emergency feathering, thus providing a deeper level of hardware-level safety. Regardless of whether an integrated or independent hardware form is adopted, the core value of the control module lies in directly linking trend warning signals to the maximum pitch rate at the end of the high-speed execution, achieving zero-delay hard correlation from data judgment to physical action.

[0081] Through the coordinated operation of processing module 201 and control module 202, the device in this embodiment completely replicates the core mechanisms of proactive trend warning and rapid risk avoidance response in the method embodiment in terms of hardware architecture. Processing module 201 provides the triggering opportunity for rapid response, and control module 202 provides substantial risk avoidance capability for trend warning. Together, they proactively establish a critical safety clearance margin before the blade collides with the tower.

[0082] This device embodiment corresponds logically to the aforementioned method embodiment and is explanatory rather than restrictive. For the same technical details, such as the specific algorithm of the rate of change, the specific value of the pitch rate, and the sub-steps for erroneous trigger elimination, etc., they have been elaborated in detail in the method embodiment and will not be repeated here. Any hardware architecture that implements the above-mentioned early warning and rapid risk avoidance collaborative logic based on the processing module and the control module should fall within the protection scope of this application.

[0083] like Figure 3 As shown, this embodiment provides a wind turbine generator set. This wind turbine generator set is the final integrated mapping of the aforementioned method embodiment and device embodiment on the physical carrier of the whole machine.

[0084] Specifically, the wind turbine generator set in this embodiment includes blades 301, a tower 302, and a blade clearance emergency protection device 200. The blades 301 are flexible structures that bear aerodynamic loads and undergo flapping deformation, while the tower 302 is a rigid main structure supporting the nacelle and blades. The dynamic distance between the blades 301 and the tower 302 is the clearance distance described in the preceding embodiments. The blade clearance emergency protection device 200 is the hardware architecture entity containing a processing module 201 and a control module 202, as described in the preceding embodiments. It is deployed in the main control cabinet inside the nacelle or in a separate safety control cabinet. It is responsible for determining the clearance deterioration rate based on clearance monitoring data and triggering an emergency feathering action at the maximum pitch rate when the rate of change meets the emergency triggering conditions.

[0085] To provide a reliable source of raw data for the blade clearance emergency protection device 200, the wind turbine generator set in this embodiment is also equipped with a clearance monitoring device. This clearance monitoring device is installed at the bottom of the nacelle or the top of the tower, and its ranging field of view can cover the critical area between the blade sweep trajectory and the tower surface, thereby capturing real-time changes in the clearance distance between the blade tip and the tower. It should be understood that although this embodiment focuses on the layout installed at the bottom of the nacelle or the top of the tower, in other embodiments, depending on the specific structural design of the unit and the radar beam coverage, the clearance monitoring device can also be installed inside the hub or on a specific observation platform in the middle of the tower, as long as it can stably and continuously acquire dynamic distance data of the blade flapping and deforming towards the tower. The selection of the installation location should not constitute a limitation of this application.

[0086] Regarding sensor types, the clearance monitoring device can employ various non-contact ranging methods, such as millimeter-wave radar, lidar, or visual ranging systems. Millimeter-wave radar has the advantages of strong penetration through rain, fog, and dust, and stable operation in all weather conditions; lidar features extremely high ranging accuracy and a very narrow beam, making it suitable for precise tracking of specific points on leaf tips; visual ranging systems, through binocular cameras or monocular image recognition algorithms, can provide rich spatial contour information. These equivalent methods achieve the same functional goal from different physical principles, namely, real-time output of clearance distance signals. Therefore, the sensor type does not constitute a limitation on this application, and any non-contact measurement method capable of outputting clearance distance data at a sufficient sampling frequency can be used as the input source for this embodiment.

[0087] Regarding sampling frequency, to accurately capture the transient abrupt changes in blade flapping deformation under sudden gusts or extreme turbulence impacts, the sampling frequency of the air clearance monitoring device must be no less than 20Hz. This frequency requirement ensures that the system can acquire at least one air clearance distance observation value within a single sampling period of 0.05 seconds, thereby accumulating 5 to 10 historical sampling points within a time window of 0.25 to 0.5 seconds. This provides sufficient density of time-series data to support the processing module in calculating the rate of change of air clearance deterioration. If the sampling frequency is too low, for example, below 10Hz, the time interval between adjacent sampling points will be too large, making it impossible to accurately depict the dynamic curve of rapid blade deformation. This can easily lead to serious lag or even missed detection in the identification of deterioration trends. Therefore, a sampling frequency of no less than 20Hz is the hardware foundation for ensuring the timeliness and reliability of early warning trends.

[0088] By integrating the blades, tower, blade clearance emergency protection device, and clearance monitoring device, this embodiment of the wind turbine generator set constructs a complete anti-sweeping closed loop at the whole machine level, from physical perception and trend recognition to high-speed action. The clearance monitoring device acts as the sensing antenna, capturing dynamic gaps through high-frequency sampling; the processing module acts as the nerve center, extracting deteriorating trends from time-series data; the control module acts as the execution drive, forcibly overcoming conventional limitations with maximum speed commands; and the pitch system acts as the muscle end, driving the blades to feather at the hardware's maximum speed. This integrated solution enables the wind turbine generator set to no longer rely on conventional shutdown logic with delayed responses or indirectly triggered safety chains when encountering sudden low clearance conditions. Instead, it possesses a high-speed self-protection capability that proactively establishes a safe clearance margin before a collision occurs, fundamentally reducing the probability of tower sweeping accidents and improving the overall survivability and operational safety of the unit under extreme wind conditions.

[0089] This system embodiment corresponds logically to the aforementioned method and device embodiments and is explanatory rather than restrictive. For the same technical details, such as the specific algorithm of the rate of change, the specific value of the pitch rate, and the sub-steps for erroneous triggering elimination, etc., they have been elaborated in detail in the previous embodiments and will not be repeated here. Any wind turbine generator set product that implements early warning and rapid risk avoidance collaborative logic based on the above-mentioned integrated architecture should fall within the protection scope of this application.

[0090] To more intuitively demonstrate the complete closed-loop effect and commercial value of the technical solution in real-world wind conditions, this embodiment substitutes the core logic of the aforementioned embodiments into a specific extreme turbulent impact application scenario for a full-process simulation.

[0091] Application scenario: A 100-meter flexible blade wind turbine is operating normally near its rated wind speed, with a current blade pitch angle of 10°. At this moment, the turbine encounters a sudden gust of turbulent wind, and the sudden change in wind direction causes the yaw error to increase sharply to over 25°, and the blade flapping deformation towards the tower begins to intensify rapidly.

[0092] The millimeter-wave radar installed at the bottom of the nacelle acquires the real-time clearance distance between the blade tip and the tower at a sampling frequency of 20Hz. And a continuous historical airspace sequence. In the initial stage of gust impact, It starts to drop rapidly from the initial safety margin of 12 meters.

[0093] Based on the current airspace distance and the historical airspace distance sequence, extract the airspace distance values ​​from the previous N=8 sampling periods in the historical sequence. ,calculate and The difference is used to determine the current rate of change in airspace deterioration, and based on the ratio of this difference to a 0.4-second time window. As the gusts of wind continued to impact, the calculated... The rate of change in airspace increased sharply, reaching 2.5 m / s, which is far greater than the preset safety threshold for airspace change rate. This indicates that the airspace is decreasing rapidly at an abnormal rate, posing an extremely high risk of sudden small airspace disruptions.

[0094] Before triggering emergency feathering, the control module cross-checked the persistence of the airspace deterioration rate and the unit's operating status. Specifically, it continuously monitored the rate of change for the next M=4 sampling periods (0.2 seconds), finding that it consistently exceeded 1.0 m / s, confirming the persistence of the deterioration trend; simultaneously, it acquired the unit's operating status, determining that the current pitch angle was 10° and the pitch rate was 0, confirming that the unit was not in a shutdown process; it calculated the current wind speed turbulence intensity, finding that the ratio of the wind speed standard deviation to the average value exceeded a preset threshold of 0.15, corroborating the actual existence of extreme turbulence impact. All of the above confirmation conditions were met, ruling out the possibility of false triggering due to instantaneous sensor noise interference.

[0095] In response to the airspace deterioration rate meeting the emergency trigger condition and passing cross-confirmation, the control module sends an emergency pitch control system command to override the maximum permissible pitch rate limit under normal operation, driving the blades to the feathering position. The target pitch angle is set to 90° feathering, the pitch rate command is the maximum permissible pitch rate of 15° / s, and the priority is designated as emergency protection priority, higher than the normal power control pitch command. Upon receiving the command, the pitch system immediately begins retracting the blades at an extremely rapid response of 15° / s.

[0096] After pitch control was completed, the system triggered the generator to disconnect from the grid and reduce to idle speed to prevent overspeed. Simultaneously, it recorded complete event data, including the trigger time, pre-trigger clearance sequence, wind speed and turbulence conditions, and pitch control execution process data. Since this was the first emergency pitch control trigger within this operating cycle, the number of triggers did not exceed the preset threshold (3 times), and although the severity was high, it did not exceed the limit requiring manual intervention. After self-checking and confirming safety, the system allowed the unit to automatically reset and restart, avoiding power generation losses caused by prolonged shutdown for inspection.

[0097] The computer program product of the readable storage medium provided in the embodiments of this application includes a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the methods described in the foregoing method embodiments. For specific implementation, please refer to the foregoing method embodiments, which will not be repeated here.

[0098] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of this application, in essence, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0099] Finally, it should be noted that the above-described embodiments are merely specific implementations of this application, used to illustrate the technical solutions of this application, and not to limit them. The scope of protection of this application is not limited thereto. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments, or make equivalent substitutions for some of the technical features, within the scope of the technology disclosed in this application. Such modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be covered within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A method for emergency protection of airspace clearance for wind turbine blades, comprising: Based on airspace monitoring data, determine the rate of change in airspace deterioration; In response to the airspace deterioration rate meeting the emergency triggering condition, an emergency feathering action is triggered at the maximum pitch rate.

2. A wind turbine blade clearance emergency protection method according to claim 1, wherein, The rate of change in airspace deterioration, determined based on airspace monitoring data, includes: The rate of change of airspace deterioration is determined based on the current airspace distance and the historical airspace sequence.

3. A wind turbine blade clearance emergency protection method according to claim 2, wherein, The rate of change in airspace deterioration is determined based on the current airspace distance and the historical airspace sequence, including: Extract the airspace distance values ​​from the previous N sampling periods from the historical airspace sequence, where N is a positive integer; Calculate the difference between the clearance distance value before the previous N sampling periods and the clearance distance value at the current moment; Based on the ratio of the difference to the corresponding time window, the net airspace deterioration rate is determined, where the time window is the total duration corresponding to N sampling periods; The airspace deterioration rate represents the rate at which the airspace distance decreases per unit time. When the difference is positive, it indicates that the airspace distance is decreasing and the airspace deterioration rate is positive, indicating that the airspace is deteriorating. When the difference is negative or zero, it indicates that the airspace distance is increasing or remaining unchanged and the airspace deterioration rate is negative or zero, indicating that the airspace is in a safe trend. The emergency triggering condition includes the airspace deterioration rate being greater than a preset airspace change rate safety threshold.

4. The wind turbine blade clearance emergency protection method of claim 1, wherein, Emergency feathering actions that trigger at maximum pitch rate include: Drive the blades to the feathering position at the maximum permissible pitch rate that covers the normal pitch rate limit.

5. A wind turbine blade clearance emergency protection method according to claim 4, wherein, The maximum permissible pitch rate is greater than 8° / s; The normal operating pitch rate is limited to 4° / s to 8° / s; Emergency feathering actions that trigger at maximum pitch rate also include: Send an emergency pitch control command to the pitch control system. The emergency pitch command includes a target pitch angle, a pitch rate command, and a priority identifier. Wherein, the target pitch angle is the feathering position angle, the pitch rate command is executed at the maximum permissible pitch rate, and the priority identifier is the emergency protection priority, which is higher than the normal power control pitch command; The pitch angle corresponding to the feathering position is around 90°, which ensures that the aerodynamic load on the blades is quickly removed and the flapping deformation of the blades towards the tower is quickly restored. Based on the angular difference between the current pitch angle position and the target feathering position, and the maximum permissible pitch rate, calculate the expected pitch action duration.

6. The wind turbine blade clearance emergency protection method of claim 1, wherein, The method further includes: In response to the current airspace distance being less than the absolute safety threshold, an emergency feathering maneuver is directly triggered at the maximum pitch rate.

7. The wind turbine generator system blade clearance emergency protection method according to claim 1, wherein, Before triggering an emergency feathering maneuver at the maximum pitch rate, the method further includes: The persistence of the airspace deterioration rate and the unit's operating status were cross-checked to rule out false triggering.

8. The wind turbine blade clearance emergency protection method of claim 1, wherein, After the emergency feathering maneuver performed at the maximum pitch rate is completed, the method further includes: Trigger the generator to disconnect from the grid or reduce it to idle speed to prevent runaway; Record complete event data that triggers the emergency feathering action. The complete event data includes the trigger time, the airspace sequence before the trigger, wind speed conditions, operating status parameters, and pitch execution process data, for subsequent fault analysis and control strategy optimization. Based on the number and severity of emergency pitch triggers, it is determined whether the unit can be allowed to automatically reset and restart, or whether manual on-site inspection and confirmation are required before it can be reconnected to the grid. The determination of whether to allow the unit to automatically reset and restart includes: If the number of emergency pitch triggers does not exceed the preset threshold and the severity does not exceed the preset severity threshold, the unit is allowed to automatically reset and restart. If the number of emergency pitch triggers exceeds the preset threshold, or the severity exceeds the preset severity threshold, manual on-site inspection and confirmation are required before the system can be reconnected to the grid.

9. An emergency protection device for the airspace clearance of a wind turbine blade, comprising: The processing module is used to determine the rate of change of airspace deterioration based on airspace monitoring data; The control module is used to trigger an emergency feathering action at the maximum pitch rate in response to the airspace deterioration rate meeting the emergency triggering condition.

10. A wind turbine generator set, comprising blades, a tower, and an emergency blade clearance protection device as described in claim 9.

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