A wind power main shaft connecting section crack early warning method and device

Abstract

The application relates to a wind power main shaft connecting section crack early warning method and device, which comprises the following steps: performing angular domain resampling on vibration signals in a connecting section vibration signal group and a high-speed shaft vibration signal group to obtain a connecting section order amplitude sequence group and a high-speed shaft order amplitude sequence group; performing frequency band screening on the vibration signals in the connecting section vibration signal group and the high-speed shaft vibration signal group to obtain a connecting section local impact characteristic sequence group and a high-speed shaft local impact characteristic sequence group; determining a stiffness degradation indication result according to synchronous changes in the connecting section order amplitude sequence group and difference changes between the connecting section order amplitude sequence group and the high-speed shaft order amplitude sequence group; and determining a local impact indication result according to difference changes in the connecting section local impact characteristic sequence group and difference changes between the connecting section local impact characteristic sequence group and the high-speed shaft local impact characteristic sequence group.

Description

Technical Field

[0001] This invention relates to the technical field of wind turbine generator condition monitoring, and in particular to a method and device for early warning of cracks in the main shaft connection section of a wind turbine. Background Technology

[0002] As wind turbines develop towards larger capacities, taller towers, and longer blades, the alternating and impact loads on the main drive system are continuously increasing. Long-term effects of wind speed variations, blade aerodynamic load fluctuations, and torsional vibrations in the drive system on the main drive structure can easily cause fatigue damage at connection points. This damage may appear weak in the early stages, but as it continues to expand, it can lead to main shaft fracture, affecting the operational safety of the wind turbine.

[0003] Existing methods for monitoring the condition of wind turbine generators mainly identify common faults such as bearing wear and gear damage through vibration amplitude, spectral composition, or statistical indicators. Because the wind turbine main shaft rotates at relatively low speeds and its operating speed varies continuously, the collected vibration signals are easily affected by the combined influence of operating loads, ambient temperature, and vibrations from other components in the transmission chain. Therefore, abnormal features resulting from early structural damage are difficult to stably separate from complex vibrations.

[0004] Therefore, existing condition monitoring methods are unable to accurately identify early cracks in the spindle connection under low speed, variable operating conditions, and multi-vibration source coupling conditions, and are prone to problems such as delayed early warning or false alarms. Summary of the Invention

[0005] To address the issue of low accuracy in existing wind turbine main shaft crack early warning systems, this application provides a method and apparatus for early warning of cracks in the connection section of a wind turbine main shaft.

[0006] The above-mentioned objective of this application is achieved through the following technical solution:

[0007] A method for early warning of cracks in the connecting section of a wind turbine main shaft, the method comprising:

[0008] Vibration signal groups of connecting sections, vibration signal groups of high-speed shafts, and high-speed shaft rotational speed pulse signals are acquired at multiple monitoring times. The vibration signal groups of connecting sections are collected from both sides of the connecting section of the shaft, and the vibration signal groups of high-speed shafts are collected from both ends of the high-speed shaft.

[0009] Using the high-speed shaft rotational speed pulse signal as an angular reference, the vibration signals in the connecting section vibration signal group and the high-speed shaft vibration signal group are resampled in the angular domain, the order amplitude is extracted and arranged in the order of the monitoring time to obtain the connecting section order amplitude sequence group and the high-speed shaft order amplitude sequence group respectively.

[0010] The vibration signals in the connecting section vibration signal group and the high-speed shaft vibration signal group are subjected to frequency band filtering, local impact features are extracted and arranged in chronological order of the monitoring time to obtain the connecting section local impact feature sequence group and the high-speed shaft local impact feature sequence group, respectively.

[0011] The stiffness degradation indication result is determined based on the synchronous changes within the connecting segment order amplitude sequence group and the difference changes between the connecting segment order amplitude sequence group and the high-speed shaft order amplitude sequence group.

[0012] The local impact indication result is determined based on the differences within the local impact characteristic sequence group of the connecting section and the differences between the local impact characteristic sequence group of the connecting section and the local impact characteristic sequence group of the high-speed shaft.

[0013] Based on the stiffness degradation indication result and the local impact indication result, a crack early warning result for the main shaft connection section is generated.

[0014] By adopting the above technical solution, the vibration change characteristics of both sides of the main shaft connection section and both ends of the high-speed shaft can be extracted under low-speed variable speed conditions. The abnormality of the main shaft connection section can be identified by the difference in order amplitude and local impact distribution, reducing the interference caused by high-speed shaft failure, fluctuation of operating conditions and common changes in wind field, and improving the accuracy, timeliness and stability of crack early warning of the main shaft connection section.

[0015] In a preferred embodiment, this application can be further configured such that: the vibration signal group of the connecting section and the vibration signal group of the high-speed shaft are synchronously acquired in the radial vertical direction, the sampling frequency of the vibration signal group of the connecting section is lower than the sampling frequency of the vibration signal group of the high-speed shaft, and the single sampling duration of the vibration signal group of the connecting section is greater than the single sampling duration of the vibration signal group of the high-speed shaft.

[0016] By adopting the above technical solution, vibration data acquisition at different locations of the main shaft connection section and the high-speed shaft can be completed at the same monitoring time. By using differentiated sampling frequencies and sampling durations, both low-frequency change records of the connection section and high-frequency vibration records of the high-speed shaft can be taken into account, thereby improving the temporal correspondence and acquisition completeness of vibration data at multiple locations.

[0017] In a preferred embodiment, this application can be further configured such that the generation process of the connecting segment order amplitude sequence group and the high-speed shaft order amplitude sequence group is as follows:

[0018] The equal-angle sampling position is determined based on the high-speed shaft rotation pulse signal;

[0019] According to the aforementioned equal-angle sampling positions, the vibration signals in the connecting section vibration signal group and the high-speed shaft vibration signal group are interpolated and resampled respectively, and the interpolated and resampled vibration signals are synchronously averaged.

[0020] The first-order amplitude of the high-speed shaft is extracted from the vibration signal after synchronous averaging. The first-order amplitude of the high-speed shaft is arranged in chronological order according to the monitoring time to obtain the sequence group of the connecting segment first-order amplitude and the sequence group of the high-speed shaft first-order amplitude.

[0021] By adopting the above technical solution, the vibration signals of the connecting section and high-speed shaft can be uniformly converted to the angular domain, reducing the spectral dispersion caused by speed fluctuations. Furthermore, by synchronous averaging, the influence of random vibration on the first-order amplitude can be reduced, enabling the formation of continuously comparable order amplitude change data at different signal acquisition locations at each monitoring time, thereby improving the stability and accuracy of stiffness change identification.

[0022] In a preferred embodiment, this application can be further configured such that the generation process of the connection segment local impact feature sequence group and the high-speed shaft local impact feature sequence group is as follows:

[0023] The vibration signals corresponding to the monitoring time in the vibration signal group of the connecting section and the vibration signal group of the high-speed shaft are respectively filtered by frequency band, and the kurtosis of each vibration signal after frequency band filtering is calculated. The kurtosis is determined as a local impact feature.

[0024] According to the signal acquisition location and monitoring time corresponding to the local impact characteristics, the local impact characteristics are arranged into the connection segment local impact characteristic sequence group and the high-speed shaft local impact characteristic sequence group, respectively.

[0025] By adopting the above technical solution, high-frequency impact changes can be extracted from vibration data at various signal acquisition locations, and continuous feature records can be formed according to the monitoring time. This makes the impact changes at different locations of the main shaft connection section and different locations of the high-speed shaft comparable, thereby improving the sensitivity and stability of local anomaly identification.

[0026] In a preferred embodiment, this application can be further configured such that the process for determining the stiffness degradation indication result is as follows:

[0027] Obtain the wind speed and power corresponding to the monitoring time, and determine the wind speed range and power range corresponding to each monitoring time based on the wind speed and power.

[0028] Based on the historical order amplitude values ​​within each wind speed and power range, dynamic threshold values ​​for each order amplitude sequence are established for each order amplitude sequence in the connecting segment order amplitude sequence group and the high-speed axis order amplitude sequence group.

[0029] The order amplitude at each monitoring time is compared with the dynamic threshold of the order amplitude for the corresponding wind speed range and power range.

[0030] When the order amplitude in the connecting segment order amplitude sequence group synchronously exceeds the corresponding dynamic threshold of the order amplitude at multiple consecutive monitoring times, and the order amplitude in the high-speed shaft order amplitude sequence group does not synchronously exceed the corresponding dynamic threshold of the order amplitude, the stiffness degradation indication result is determined.

[0031] By adopting the above technical solution, matching order amplitude judgment benchmarks can be established for each signal acquisition location based on different wind speed and power ranges, reducing amplitude fluctuation interference caused by load changes, and identifying stiffness changes in the connecting section by the over-limit difference between the connecting section and the high-speed shaft, thereby improving the working condition adaptability and accuracy of stiffness degradation judgment.

[0032] In a preferred embodiment, this application can be further configured such that the process for determining the local impact indication result is as follows:

[0033] The local impact feature sequence of the corresponding main shaft connecting segment near the main shaft in the local impact feature sequence group of the connecting segment is determined as the local impact feature sequence of the main shaft side, and the local impact feature sequence of the corresponding main shaft connecting segment near the gearbox side in the local impact feature sequence group of the connecting segment is determined as the local impact feature sequence of the gearbox side.

[0034] Based on the local impact characteristics of each local impact characteristic sequence in the main shaft side local impact characteristic sequence, the gearbox side local impact characteristic sequence, and the high-speed shaft local impact characteristic sequence group at adjacent monitoring times, the changing trend of each local impact characteristic sequence is determined;

[0035] When the change trend of the local impact characteristic sequence on the main shaft side is upward over multiple consecutive monitoring times, and the change trends of each local impact characteristic sequence in the gearbox side and the high-speed shaft local impact characteristic sequence group do not show an upward trend within the same monitoring time, the local impact indication result is determined.

[0036] By adopting the above technical solution, the source of local anomalies can be identified by the difference in impact changes at various positions on the main shaft side, gearbox side, and high-speed shaft. When the impact on the main shaft side continues to rise while other positions remain stable, a targeted judgment can be made, reducing the interference caused by gearbox vibration or high-speed shaft vibration, and improving the positioning accuracy and reliability of local impact identification.

[0037] In a preferred embodiment, this application can be further configured such that the generation process of the crack early warning result of the spindle connection section is as follows:

[0038] The wind turbine corresponding to the vibration signal group of the connecting section is identified as the target wind turbine. Multiple comparison wind turbines are obtained, and the comparison wind turbines and the target wind turbines are located in the same wind farm, have the same model and match the operating conditions.

[0039] By comparing the order amplitude sequence of the connection segment of the target wind turbine with the order amplitude sequence of the connection segment of each of the comparison wind turbines, the order variation relationship between the turbines is determined.

[0040] When the stiffness degradation indication result indicates that the main shaft connection section has undergone stiffness degradation, the local impact indication result indicates that the main shaft connection section has undergone local impact, and the inter-unit order change relationship indicates that the target wind turbine and each of the comparison wind turbines have not undergone synchronous change, a crack warning result for the main shaft connection section is generated.

[0041] By adopting the above technical solution, the order changes of the same type and operating conditions of wind turbines in the same wind farm can be used as a common reference to distinguish between common fluctuations in the wind farm and independent anomalies of the target wind turbine. Crack early warning results can be generated by combining stiffness degradation indicators and local impact indicators, thereby reducing misjudgments caused by environmental changes and improving the accuracy and reliability of crack early warning.

[0042] In a preferred embodiment, this application can be further configured such that the process of generating the crack early warning result of the spindle connection segment also includes:

[0043] From the connected segment order amplitude sequence group, determine the main shaft side order amplitude sequence that corresponds to the same signal acquisition position as the main shaft side local impact feature sequence;

[0044] The relationship between the two features is determined based on the changing trends of the main shaft side order amplitude sequence and the main shaft side local impact feature sequence at the same monitoring time.

[0045] When the dual-feature synergistic change relationship indicates that the order amplitude sequence of the main shaft side and the local impact characteristic sequence of the main shaft side synchronously form an upward trend within multiple consecutive monitoring times, and when both the stiffness degradation indication result and the local impact indication result indicate anomalies, the crack warning result of the main shaft connection segment is generated.

[0046] By adopting the above technical solution, it is possible to correlate order amplitude changes and local impact changes within the same signal acquisition location and the same monitoring period. When both types of features rise synchronously and the corresponding indication results are abnormal, a crack warning is generated, reducing misjudgments caused by single feature fluctuations and improving the accuracy and reliability of crack identification.

[0047] In a preferred embodiment, this application can be further configured such that the process for determining the order change relationship between the units is as follows:

[0048] Based on the target wind turbine and the sequence of order amplitude values ​​of the connecting segments of each of the comparison wind turbines, the target order variation trend and multiple comparison order variation trends are determined respectively.

[0049] When multiple comparison order change trends change synchronously, the common change trend of the wind field is determined based on the multiple comparison order change trends;

[0050] By comparing the target order change trend with the common change trend of the wind field, when the target order change trend and the common change trend of the wind field are not synchronized, the order change relationship between the units is determined to indicate that the target wind turbine and each of the comparison wind turbines have not changed synchronously.

[0051] By adopting the above technical solution, the common trend of wind farm changes can be extracted from the order changes of multiple wind turbine units under the same operating conditions. The difference between the target order change trend and the common trend of wind farm changes can be used to identify independent anomalies of individual units, reduce misjudgments caused by seasonal temperature changes and fluctuations in the common operating conditions of the wind farm, and improve the accuracy of anomaly identification between units.

[0052] The second objective of this invention is achieved through the following technical solution:

[0053] A wind turbine main shaft connection section crack early warning device, the device comprising:

[0054] The signal acquisition module is used to acquire the vibration signal group of the connecting section, the vibration signal group of the high-speed shaft, and the high-speed shaft rotational speed pulse signal at multiple monitoring times. The vibration signal group of the connecting section is collected from both sides of the connecting section of the shaft, and the vibration signal group of the high-speed shaft is collected from both ends of the high-speed shaft.

[0055] The order amplitude sequence generation module is used to perform angular domain resampling on the vibration signals in the connecting section vibration signal group and the high-speed shaft vibration signal group, using the high-speed shaft rotation speed pulse signal as an angular reference, extracting the order amplitude, and arranging them in the order of the monitoring time to obtain the connecting section order amplitude sequence group and the high-speed shaft order amplitude sequence group respectively.

[0056] The local impact feature sequence generation module is used to perform frequency band filtering on the vibration signals in the connecting section vibration signal group and the high-speed shaft vibration signal group, extract local impact features, and arrange them in the order of the monitoring time to obtain the connecting section local impact feature sequence group and the high-speed shaft local impact feature sequence group, respectively.

[0057] The stiffness degradation indication result determination module is used to determine the stiffness degradation indication result based on the synchronous changes within the connecting segment order amplitude sequence group and the difference changes between the connecting segment order amplitude sequence group and the high-speed shaft order amplitude sequence group.

[0058] The local impact indication result determination module is used to determine the local impact indication result based on the difference changes within the local impact feature sequence group of the connecting section and the difference changes between the local impact feature sequence group of the connecting section and the local impact feature sequence group of the high-speed shaft.

[0059] The crack early warning result generation module is used to generate a crack early warning result for the main shaft connection section based on the stiffness degradation indication result and the local impact indication result.

[0060] By adopting the above technical solution, the vibration change characteristics of both sides of the main shaft connection section and both ends of the high-speed shaft can be extracted under low-speed variable speed conditions. The abnormality of the main shaft connection section can be identified by the difference in order amplitude and local impact distribution, reducing the interference caused by high-speed shaft failure, fluctuation of operating conditions and common changes in wind field, and improving the accuracy, timeliness and stability of crack early warning of the main shaft connection section.

[0061] In summary, this application includes at least one of the following beneficial technical effects:

[0062] By adopting the above technical solution, the vibration change characteristics of both sides of the main shaft connection section and both ends of the high-speed shaft can be extracted under low-speed variable speed conditions. The abnormality of the main shaft connection section can be identified by the difference in order amplitude and local impact distribution, reducing the interference caused by high-speed shaft failure, fluctuation of operating conditions and common changes in wind field, and improving the accuracy, timeliness and stability of crack early warning of the main shaft connection section. Attached Figure Description

[0063] Figure 1 This is a flowchart of a method for early warning of cracks in the connecting section of a wind turbine main shaft according to an embodiment of this application.

[0064] Figure 2 This is a flowchart illustrating the implementation of step S10 in a wind turbine main shaft connection section crack early warning method according to an embodiment of this application.

[0065] Figure 3 This is a flowchart illustrating the implementation of step S20 in a wind turbine main shaft connection section crack early warning method according to an embodiment of this application.

[0066] Figure 4 This is a flowchart illustrating the implementation of step S30 in a wind turbine main shaft connection section crack early warning method according to an embodiment of this application.

[0067] Figure 5 This is a flowchart illustrating the implementation of step S40 in a wind turbine main shaft connection section crack early warning method according to an embodiment of this application;

[0068] Figure 6 This is a flowchart illustrating the implementation of step S50 in a wind turbine main shaft connection section crack early warning method according to an embodiment of this application.

[0069] Figure 7 This is a flowchart illustrating the implementation of step S60 in a wind turbine main shaft connection section crack early warning method according to an embodiment of this application.

[0070] Figure 8 This is a flowchart illustrating the implementation of step S60 in a wind turbine main shaft connection section crack early warning method according to an embodiment of this application.

[0071] Figure 9 This is a flowchart illustrating the implementation of step S603 in a wind turbine main shaft connection section crack early warning method according to an embodiment of this application.

[0072] Figure 10 This is a schematic diagram of a device according to one embodiment of this application. Detailed Implementation

[0073] The present application will be further described in detail below with reference to the accompanying drawings.

[0074] In one embodiment, such as Figure 1 As shown, this application discloses a method for early warning of cracks in the connection section of a wind turbine main shaft, which specifically includes the following steps:

[0075] S10: Acquire vibration signal groups of connecting sections, high-speed shaft vibration signal groups, and high-speed shaft rotational speed pulse signals at multiple monitoring times. The vibration signal groups of connecting sections are collected from both sides of the connecting section of the main shaft, and the vibration signal groups of high-speed shafts are collected from both ends of the high-speed shaft.

[0076] In this embodiment, the multiple monitoring times are multiple signal acquisition times continuously determined according to a preset monitoring cycle, the connecting section vibration signal group is a collection of vibration signals acquired from both sides of the main shaft connecting section, the high-speed shaft vibration signal group is a collection of vibration signals acquired from both ends of the high-speed shaft, and the high-speed shaft rotation speed pulse signal is a pulse signal continuously output by the key phase sensor during the rotation of the high-speed shaft.

[0077] Specifically, piezoelectric acceleration vibration sensors are installed at the vertical radial positions of the main bearing housing and the first-stage planetary carrier end cover of the gearbox, respectively; piezoelectric acceleration vibration sensors are installed at the vertical radial positions of the high-speed output shaft end cover of the gearbox and the generator drive end bearing end cover, respectively; and a key phase sensor is installed at the high-speed shaft half coupling position.

[0078] At each monitoring moment, the condition monitoring system synchronously acquires data from all piezoelectric acceleration vibration sensors and key phase sensors. Vibration signals from the main bearing housing and the end cover of the first-stage planetary carrier of the gearbox are continuously acquired for 16 seconds at a sampling frequency of 12800 Hz. The acquired vibration signals are recorded as vibration signal groups for the connecting section according to the corresponding signal acquisition positions.

[0079] The vibration signals of the high-speed output shaft end cover of the gearbox and the bearing end cover of the generator drive end were continuously collected for 5.12 seconds at a sampling frequency of 25600 Hz. The collected vibration signals were recorded as high-speed shaft vibration signal groups according to the corresponding signal collection positions.

[0080] While acquiring the vibration signal groups of the connecting section and the high-speed shaft, the pulses output by the key phase sensor and the generation time of each pulse are read to form the high-speed shaft speed pulse signal. The vibration signal groups of the connecting section, the high-speed shaft, and the high-speed shaft speed pulse signal are then associated and stored with the corresponding monitoring times.

[0081] S20: Using the high-speed shaft rotational speed pulse signal as the angle reference, the vibration signals in the connecting section vibration signal group and the high-speed shaft vibration signal group are resampled in the angular domain, the order amplitude is extracted and arranged in the order of monitoring time to obtain the connecting section order amplitude sequence group and the high-speed shaft order amplitude sequence group respectively.

[0082] In this embodiment, the angular reference is the reference for determining the sampling position of each vibration signal based on the rotation angle of the high-speed shaft. Angular domain resampling is the conversion of vibration signals collected according to time intervals into vibration signals arranged according to angular intervals. The order amplitude is the amplitude of the vibration signal after angular domain resampling at the first order position of the high-speed shaft. The connecting segment order amplitude sequence group is a set of sequences formed by arranging the order amplitudes on both sides of the main shaft connecting segment according to the monitoring time. The high-speed shaft order amplitude sequence group is a set of sequences formed by arranging the order amplitudes at both ends of the high-speed shaft according to the monitoring time.

[0083] Specifically, the generation time of each pulse in the high-speed shaft rotation pulse signal is read, the generation time between two adjacent pulses is determined as one high-speed shaft rotation cycle, and each high-speed shaft rotation cycle is divided into multiple equal angular intervals, and the corresponding sampling time is determined according to each equal angular interval.

[0084] Vibration signals from the connecting section vibration signal group and the high-speed shaft vibration signal group are read separately. The vibration value corresponding to each sampling time is calculated using Lagrange interpolation. The calculated vibration values ​​are arranged according to the angular position to form the angular domain waveform corresponding to each vibration signal.

[0085] Select angular domain waveforms of no less than eight consecutive high-speed shaft rotation cycles, synchronously average the vibration values ​​at the same angular position, and perform order spectrum analysis on the synchronously averaged angular domain waveforms to extract the order amplitude corresponding to the first order position of the high-speed shaft.

[0086] At each monitoring moment, the order amplitude values ​​of each vibration signal in the vibration signal group of the connecting section are recorded and arranged in chronological order of monitoring moments to form a sequence group of order amplitude values ​​of the connecting section. Similarly, the order amplitude values ​​of each vibration signal in the vibration signal group of the high-speed shaft are recorded and arranged in chronological order of monitoring moments to form a sequence group of order amplitude values ​​of the high-speed shaft.

[0087] S30: Perform frequency band filtering on the vibration signals in the connecting section vibration signal group and the high-speed shaft vibration signal group, extract local impact features, and arrange them in chronological order of monitoring time to obtain the connecting section local impact feature sequence group and the high-speed shaft local impact feature sequence group, respectively.

[0088] In this embodiment, frequency band filtering is to retain the vibration components in the vibration signal within the corresponding frequency range according to a preset cutoff frequency. Local impact features are the kurtosis of the vibration signal after frequency band filtering. The local impact feature sequence group of the connecting section is a set of sequences formed by arranging the local impact features on both sides of the main shaft connecting section according to the monitoring time. The local impact feature sequence group of the high-speed shaft is a set of sequences formed by arranging the local impact features at both ends of the high-speed shaft according to the monitoring time.

[0089] Specifically, the vibration signals corresponding to each monitoring time in the vibration signal group of the connecting section and the vibration signal group of the high-speed shaft are read respectively. The read vibration signals are high-pass filtered, and 2000 Hz is set as the preset cutoff frequency to obtain the vibration signal after frequency band filtering.

[0090] For each monitoring moment, the local impact characteristics of each vibration signal after frequency band filtering are calculated according to the following formula:

[0091] Where K represents the local impact characteristic, This represents the i-th vibration value in the vibration signal after frequency band filtering. is the average value of each vibration value in the vibration signal after band filtering, and N is the number of vibration values ​​contained in the vibration signal after band filtering.

[0092] Record the local impact characteristics corresponding to each monitoring time according to the signal acquisition location. Arrange the local impact characteristics extracted from the vibration signal group of the connecting section in the order of monitoring time to form the local impact characteristic sequence group of the connecting section. Arrange the local impact characteristics extracted from the vibration signal group of the high-speed shaft in the order of monitoring time to form the local impact characteristic sequence group of the high-speed shaft.

[0093] S40: Determine the stiffness degradation indication result based on the synchronous changes within the connecting section order amplitude sequence group and the differential changes between the connecting section order amplitude sequence group and the high-speed shaft order amplitude sequence group.

[0094] Specifically, the wind speed and power corresponding to each monitoring moment are obtained, and the wind speed range and power range corresponding to each monitoring moment are determined according to the preset wind speed interval and preset power interval.

[0095] Read the historical order amplitude values ​​within each wind speed range and power range, calculate the average historical order amplitude value and the standard deviation of the historical order amplitude value corresponding to each order amplitude value sequence, and determine the sum of the average historical order amplitude value and three times the standard deviation of the historical order amplitude value as the dynamic threshold of the order amplitude value of the corresponding order amplitude value sequence.

[0096] According to the chronological order of monitoring times, the order amplitude of each order amplitude sequence in the connecting segment order amplitude sequence group is compared with the dynamic threshold of the order amplitude for the corresponding wind speed and power ranges. When each order amplitude sequence in the connecting segment order amplitude sequence group exceeds the corresponding dynamic threshold of the order amplitude for multiple consecutive monitoring times, and the order amplitude at adjacent monitoring times is increasing, it is determined that synchronous changes have occurred within the connecting segment order amplitude sequence group.

[0097] Within the same monitoring time, the order amplitude of each order amplitude sequence in the high-speed shaft order amplitude sequence group is compared with the corresponding order amplitude dynamic threshold. When each order amplitude sequence in the high-speed shaft order amplitude sequence group does not synchronously exceed the corresponding order amplitude dynamic threshold and does not show a continuous upward trend, it is determined that a difference exists between the connecting segment order amplitude sequence group and the high-speed shaft order amplitude sequence group.

[0098] When synchronous changes occur within the connecting segment order amplitude sequence group, and differential changes occur between the connecting segment order amplitude sequence group and the high-speed shaft order amplitude sequence group, the stiffness degradation indication result is determined.

[0099] S50: Determine the local impact indication result based on the differences within the local impact characteristic sequence group of the connecting section and the differences between the local impact characteristic sequence group of the connecting section and the local impact characteristic sequence group of the high-speed shaft.

[0100] In this embodiment, the local impact indication result is the indication result formed when the difference changes within the local impact feature sequence group of the connecting section and the difference changes between the local impact feature sequence group of the connecting section and the local impact feature sequence group of the high-speed shaft meet the preset judgment conditions.

[0101] Specifically, based on the signal acquisition location corresponding to each local impact feature sequence in the connecting section local impact feature sequence group, the local impact feature sequence of the corresponding main shaft connecting section near the main shaft is determined as the main shaft side local impact feature sequence, and the local impact feature sequence of the corresponding main shaft connecting section near the gearbox is determined as the gearbox side local impact feature sequence.

[0102] Historical local impact characteristics are read within each wind speed and power range. The average value and standard deviation of historical local impact characteristics corresponding to each local impact characteristic sequence are calculated. The sum of the average value of historical local impact characteristics and three times the standard deviation of historical local impact characteristics is determined as the dynamic threshold of local impact characteristics for the corresponding local impact characteristic sequence.

[0103] According to the chronological order of monitoring times, the local impact features in the main shaft side local impact feature sequence are compared with the corresponding local impact feature dynamic thresholds. When the local impact features in the main shaft side local impact feature sequence exceed the corresponding local impact feature dynamic thresholds in multiple consecutive monitoring times, and the local impact features in adjacent monitoring times show an upward trend, it is determined that the main shaft side local impact feature sequence has formed an upward change.

[0104] Within the same monitoring time, the local impact characteristics of each local impact characteristic sequence in the gearbox-side local impact characteristic sequence and the high-speed shaft local impact characteristic sequence group are compared with the corresponding local impact characteristic dynamic thresholds. When none of the local impact characteristic sequences in the gearbox-side local impact characteristic sequence and the high-speed shaft local impact characteristic sequence group continuously exceed the corresponding local impact characteristic dynamic thresholds, and none of them continuously show an upward trend, it is determined that neither the gearbox-side local impact characteristic sequence nor the high-speed shaft local impact characteristic sequence group has formed an upward change.

[0105] When the local impact characteristic sequence on the main shaft side shows an upward change, and neither the local impact characteristic sequence on the gearbox side nor the local impact characteristic sequence on the high-speed shaft shows an upward change, the local impact indication result is determined.

[0106] S60: Generate early warning results for cracks in the main shaft connection section based on stiffness degradation indication results and local impact indication results.

[0107] Specifically, the wind turbines corresponding to the vibration signal groups of the connecting sections are identified as the target wind turbines, and multiple wind turbines of the same model are selected from the same wind farm as comparison wind turbines. According to the wind speed and power ranges corresponding to each monitoring time, the corresponding connecting section order amplitude sequence groups are read from each comparison wind turbine.

[0108] The changing trends of the order amplitude sequence groups of the connection segments of each comparative wind turbine were determined over multiple consecutive monitoring periods. When the order amplitude sequence groups of the connection segments of multiple comparative wind turbines changed synchronously, the common changing trend of the wind field was determined based on the synchronously changing order amplitude sequence groups of the connection segments.

[0109] Determine the target order variation trend corresponding to the target wind turbine's connected segment order amplitude sequence group, and compare the target order variation trend with the common variation trend of the wind farm. When the target order variation trend is not synchronized with the common variation trend of the wind farm, it is determined that the target wind turbine has formed an independent variation.

[0110] The main shaft side order amplitude sequence corresponding to the same signal acquisition position as the main shaft side local impact characteristic sequence is read from the connection segment order amplitude sequence group, and the changing trends of the main shaft side order amplitude sequence and the main shaft side local impact characteristic sequence are compared within the same monitoring time. When the main shaft side order amplitude sequence and the main shaft side local impact characteristic sequence synchronously increase in multiple consecutive monitoring times, it is determined that a dual-feature coordinated change has formed.

[0111] When the stiffness degradation indication result and the local impact indication result are both determined, and the target wind turbine forms independent changes and dual-feature synergistic changes, a crack early warning result for the main shaft connection section is generated.

[0112] The amplitude of the main shaft side order amplitude sequence exceeding the corresponding order amplitude dynamic threshold, the amplitude of the main shaft side local impact characteristic sequence exceeding the corresponding local impact characteristic dynamic threshold, and the duration of continuous exceeding the corresponding dynamic threshold are calculated respectively. Based on the amplitude and duration, the warning level is determined as early hidden danger warning, crack propagation warning, or fracture critical warning.

[0113] In one embodiment, such as Figure 2 As shown, in step S10, the vibration signal group of the connecting section and the vibration signal group of the high-speed shaft are synchronously acquired along the radial vertical direction. The sampling frequency of the vibration signal group of the connecting section is lower than that of the vibration signal group of the high-speed shaft, and the single sampling duration of the vibration signal group of the connecting section is greater than that of the vibration signal group of the high-speed shaft.

[0114] In this embodiment, the radial vertical direction is the signal acquisition direction that is perpendicular to the corresponding axis and extends in the vertical direction. Synchronous acquisition means sending the same acquisition start command to each vibration signal acquisition channel at the same monitoring time. The sampling frequency is the number of vibration values ​​acquired per unit time. The single sampling duration is the duration of continuous acquisition of vibration values ​​after each acquisition start.

[0115] Specifically, the piezoelectric acceleration vibration sensors for acquiring the vibration signal groups of the connecting section and the high-speed shaft are set to be installed radially vertically, so that the signal acquisition direction of each piezoelectric acceleration vibration sensor is radially vertical.

[0116] At each monitoring moment, the condition monitoring system synchronous acquisition unit sends the same acquisition start command to each vibration signal acquisition channel of the acquisition connection section vibration signal group and the high-speed shaft vibration signal group, and records the moment when each vibration signal acquisition channel starts acquiring vibration values.

[0117] Set the sampling frequency of the vibration signal acquisition channel for the connecting section vibration signal group to 12800 Hz and the single sampling duration to 16 seconds. Set the sampling frequency of the vibration signal acquisition channel for the high-speed shaft vibration signal group to 25600 Hz and the single sampling duration to 5.12 seconds.

[0118] After receiving the acquisition start command, each vibration signal acquisition channel continuously acquires vibration values ​​according to the corresponding sampling frequency and single sampling duration, and stores the acquired vibration values ​​according to the corresponding signal acquisition location and monitoring time.

[0119] In one embodiment, such as Figure 3 As shown, in step S20, the process of generating the connection segment order amplitude sequence group and the high-speed shaft order amplitude sequence group is as follows:

[0120] S201: Determine the equal angle sampling position based on the high-speed shaft speed pulse signal.

[0121] In this embodiment, the equal-angle sampling position is the vibration signal sampling position determined at equal angular intervals within each rotation cycle of the high-speed shaft.

[0122] Specifically, the high-speed shaft rotation speed pulse signals are read in chronological order of pulse generation. The time range between the generation times of two adjacent pulses is defined as one high-speed shaft rotation cycle, and the high-speed shaft rotation angle corresponding to the generation time of the previous pulse is defined as the starting angle.

[0123] According to the preset number of angle segments, the circumferential angle corresponding to one high-speed shaft rotation cycle is divided into multiple equal angle intervals. Based on the proportion of each equal angle interval to the circumferential angle, the corresponding sampling time is determined between the generation times of two adjacent pulses.

[0124] The rotation angle and time position of the high-speed shaft at each sampling moment are associated and recorded, and arranged in the order of the rotation angle of the high-speed shaft to obtain the equiangular sampling position corresponding to each high-speed shaft rotation cycle.

[0125] S202: According to the equal angle sampling position, the vibration signals in the connecting section vibration signal group and the high-speed shaft vibration signal group are interpolated and resampled respectively, and the vibration signals after interpolation and resampling are synchronously averaged.

[0126] In this embodiment, interpolation resampling involves calculating the corresponding vibration value from the vibration signal collected at time intervals based on the sampling time corresponding to the equal angle sampling position, and rearranging the vibration values ​​according to the rotation angle of the high-speed shaft. Synchronous averaging involves averaging the vibration values ​​corresponding to the same equal angle sampling position within multiple high-speed shaft rotation cycles.

[0127] Specifically, the time range corresponding to the vibration signal group of the connecting section, the vibration signal group of the high-speed shaft, and the high-speed shaft speed pulse signal is determined, and the equiangular sampling positions within the time range and the sampling time corresponding to each equiangular sampling position are read.

[0128] For each equiangular sampling position, multiple vibration values ​​located before and after the corresponding sampling time are read from each vibration signal in the connecting section vibration signal group and the high-speed shaft vibration signal group. The vibration value at the corresponding sampling time is calculated using Lagrange interpolation. The calculated vibration values ​​are arranged in the order of the high-speed shaft rotation angle to form the angular domain waveform corresponding to each high-speed shaft rotation period.

[0129] Angular waveforms of at least eight high-speed shaft rotation cycles are continuously selected. Each angular waveform is aligned according to the equal angle sampling position. The average value of the vibration value corresponding to the same equal angle sampling position is calculated. The average values ​​are arranged in the order of the high-speed shaft rotation angle to obtain the synchronously averaged vibration signal corresponding to each vibration signal.

[0130] S203: Extract the first-order amplitude of the high-speed shaft from the vibration signal after synchronous averaging, arrange the first-order amplitude of the high-speed shaft according to the order of monitoring time, and obtain the sequence group of the connecting section first-order amplitude and the sequence group of the high-speed shaft first-order amplitude.

[0131] In this embodiment, the first-order amplitude of the high-speed shaft is the amplitude of the vibration component that changes periodically once for each rotation cycle of the high-speed shaft in the vibration signal after synchronous averaging.

[0132] Specifically, for each monitoring moment, the synchronously averaged vibration signals corresponding to each vibration signal in the connecting section vibration signal group and the high-speed shaft vibration signal group are read respectively, and the synchronously averaged vibration signals are subjected to discrete Fourier transform according to the arrangement order of the high-speed shaft rotation angle to obtain the corresponding order spectrum.

[0133] One high-speed shaft rotation period is defined as one order period. The first order position is determined from the order spectrum. The complex spectrum value corresponding to the first order position is read. The modulus of the complex spectrum value is calculated and normalized according to the number of angular domain samples to obtain the first order amplitude of the high-speed shaft of the corresponding vibration signal at the corresponding monitoring time.

[0134] The first-order amplitude of the high-speed shaft extracted from each vibration signal in the vibration signal group of the connecting section is associated with the corresponding signal acquisition position and monitoring time. The first-order amplitude of the high-speed shaft corresponding to each signal acquisition position is arranged in chronological order of monitoring time to obtain the connecting section first-order amplitude sequence group.

[0135] The first-order amplitude of the high-speed shaft is extracted from each vibration signal in the high-speed shaft vibration signal group and associated with the corresponding signal acquisition position and monitoring time. The first-order amplitude of the high-speed shaft corresponding to each signal acquisition position is arranged in chronological order of monitoring time to obtain the high-speed shaft first-order amplitude sequence group.

[0136] In one embodiment, such as Figure 4 As shown, in step S30, the process of generating the local impact characteristic sequence group of the connecting section and the local impact characteristic sequence group of the high-speed shaft is as follows:

[0137] S301: Perform frequency band filtering on the vibration signals at the corresponding monitoring time in the vibration signal group of the connecting section and the vibration signal group of the high-speed shaft, calculate the kurtosis of each vibration signal after frequency band filtering, and determine the kurtosis as a local impact characteristic.

[0138] In this embodiment, each vibration signal after frequency band filtering is a vibration signal obtained by high-pass filtering the vibration signal at the corresponding monitoring time according to a preset cutoff frequency.

[0139] Specifically, each vibration signal in the connecting section vibration signal group and the high-speed shaft vibration signal group is read according to the monitoring time. 2000 Hz is set as the preset cutoff frequency, and each read vibration signal is high-pass filtered to obtain each vibration signal after frequency band filtering.

[0140] After frequency band filtering, read each vibration value in each vibration signal in sequence, calculate the average value of each vibration value, and calculate the second-order central moment and the fourth-order central moment based on the difference between each vibration value and the average value.

[0141] Calculate the ratio of the fourth-order central moment to the square of the second-order central moment, determine the calculated ratio as the kurtosis of the corresponding vibration signal, and determine the kurtosis as the local impact characteristic of the corresponding signal acquisition location and monitoring time.

[0142] S302: According to the signal acquisition location and monitoring time corresponding to the local impact characteristics, the local impact characteristics are arranged into the connecting section local impact characteristic sequence group and the high-speed shaft local impact characteristic sequence group respectively.

[0143] In this embodiment, local impact features are divided according to the signal acquisition location, and arranged in chronological order of monitoring time at the same signal acquisition location.

[0144] Specifically, the signal acquisition location and monitoring time corresponding to each local impact feature are read, and the source of the local impact feature is determined to be the vibration signal group of the connecting section or the vibration signal group of the high-speed shaft based on the corresponding signal acquisition location.

[0145] For the local impact characteristics originating from the vibration signal group of the connecting section, they are classified according to the signal acquisition positions on both sides of the main shaft connecting section. The local impact characteristics corresponding to the same signal acquisition position are arranged in chronological order of monitoring time to form a local impact characteristic sequence corresponding to the signal acquisition position. The local impact characteristic sequences corresponding to both sides of the main shaft connecting section are combined into a connecting section local impact characteristic sequence group.

[0146] For the local impact characteristics originating from the high-speed shaft vibration signal group, they are classified according to the signal acquisition positions at both ends of the high-speed shaft. The local impact characteristics corresponding to the same signal acquisition position are arranged in chronological order of monitoring time to form a local impact characteristic sequence corresponding to the signal acquisition position. The local impact characteristic sequences corresponding to both ends of the high-speed shaft are combined into a high-speed shaft local impact characteristic sequence group.

[0147] In one embodiment, such as Figure 5 As shown, in step S40, the process of determining the stiffness degradation indication result is as follows:

[0148] S401: Obtain the wind speed and power corresponding to the monitoring time, and determine the wind speed range and power range corresponding to each monitoring time based on the wind speed and power.

[0149] In this embodiment, the wind speed is the wind speed value recorded in the wind turbine operating data, the power is the output power value recorded in the wind turbine operating data, the wind speed range is the numerical range defined by two adjacent preset wind speed boundary values, and the power range is the numerical range defined by two adjacent preset power boundary values.

[0150] Specifically, the wind speed and output power values ​​are read from the wind turbine operation data according to the monitoring time, and the read wind speed value is determined as wind speed, and the read output power value is determined as power.

[0151] Multiple wind speed boundary values ​​are pre-set in ascending order, and the range between any two adjacent wind speed boundary values ​​is defined as a wind speed interval. Similarly, multiple power boundary values ​​are pre-set in ascending order, and the range between any two adjacent power boundary values ​​is defined as a power interval.

[0152] The wind speed is compared sequentially with each wind speed boundary value. The wind speed interval where the lower boundary value is less than or equal to the wind speed and the upper boundary value is greater than the wind speed is determined as the wind speed interval for the corresponding monitoring time.

[0153] The power is compared sequentially with each power boundary value. The power interval where the lower boundary value is less than or equal to the power and the upper boundary value is greater than the power is determined as the power interval for the corresponding monitoring time.

[0154] S402: Based on the historical order amplitude values ​​in each wind speed range and power range, establish dynamic threshold values ​​for each order amplitude sequence in the connecting section order amplitude sequence group and the high-speed axis order amplitude sequence group.

[0155] In this embodiment, the historical order amplitude is the order amplitude recorded before the current monitoring time, which has a corresponding signal acquisition location, wind speed range, and power range. The dynamic threshold of the order amplitude is a threshold established for each order amplitude sequence and the corresponding wind speed range and power range, and recalculated according to a preset update cycle.

[0156] Specifically, the historical amplitude values ​​recorded before the current monitoring time are read, and the historical amplitude values ​​are classified according to the signal acquisition location, wind speed range, and power range corresponding to each historical amplitude value.

[0157] For each order amplitude sequence in the connecting section order amplitude sequence group and the high-speed axis order amplitude sequence group, read M historical order amplitudes within the same wind speed range and the same power range, and calculate the average and standard deviation of the historical order amplitudes according to the following formula:

[0158] , ,in, Let M be the amplitude of the Mth historical order, where M is the number of historical order amplitudes. The average amplitude of historical orders The standard deviation of the historical order amplitude.

[0159] The dynamic threshold of the order amplitude sequence in the corresponding wind speed and power ranges is calculated using the following formula: , where T is the dynamic threshold of the order amplitude.

[0160] Each order amplitude dynamic threshold is associated with and stored in relation to its corresponding order amplitude sequence, wind speed range, and power range. At the preset update cycle, newly added historical order amplitude values ​​are categorized accordingly, and the corresponding order amplitude dynamic threshold is recalculated.

[0161] S403: Compare the order amplitude at each monitoring time with the dynamic threshold of the order amplitude for the corresponding wind speed and power ranges.

[0162] In this embodiment, the order amplitude at each monitoring moment is compared with the corresponding order amplitude dynamic threshold according to the corresponding order amplitude sequence, wind speed range, and power range.

[0163] Specifically, for each monitoring moment, the order amplitudes in the connection segment order amplitude sequence group and the high-speed shaft order amplitude sequence group are read respectively, and the order amplitude sequence to which the order amplitude belongs is determined according to the signal acquisition position corresponding to the order amplitude.

[0164] Read the wind speed and power ranges for the corresponding monitoring time, and query the corresponding dynamic threshold of the order amplitude based on the order amplitude sequence, wind speed range, and power range to which the order amplitude belongs.

[0165] The order amplitude is compared with the queried dynamic threshold for order amplitude. When the order amplitude is greater than the dynamic threshold, it is recorded that the order amplitude exceeds the dynamic threshold; when the order amplitude is less than or equal to the dynamic threshold, it is recorded that the order amplitude does not exceed the dynamic threshold.

[0166] S404: When the order amplitude in the connecting section order amplitude sequence group synchronously exceeds the corresponding order amplitude dynamic threshold at multiple consecutive monitoring times, and the order amplitude in the high-speed shaft order amplitude sequence group does not synchronously exceed the corresponding order amplitude dynamic threshold, the stiffness degradation indication result is determined.

[0167] In this embodiment, "synchronous exceedance" means that the order amplitude of each order amplitude sequence in the connecting segment order amplitude sequence group exceeds its corresponding dynamic threshold for order amplitude within the same consecutive multiple monitoring times, while "non-synchronous exceedance" means that the order amplitude of each order amplitude sequence in the high-speed shaft order amplitude sequence group does not simultaneously exceed its corresponding dynamic threshold for order amplitude within the same monitoring time.

[0168] Specifically, according to the order of monitoring time, the comparison states corresponding to each order amplitude in the connecting segment order amplitude sequence group and the high-speed shaft order amplitude sequence group are read respectively, and multiple consecutive monitoring times are selected according to the preset number of consecutive times.

[0169] For a selected series of consecutive monitoring times, it is determined whether the order amplitude of each order amplitude sequence in the connecting segment order amplitude sequence group exceeds its corresponding dynamic threshold. When the order amplitude of each order amplitude sequence exceeds its corresponding dynamic threshold in a series of consecutive monitoring times, it is determined that the order amplitude in the connecting segment order amplitude sequence group has synchronously exceeded its corresponding dynamic threshold.

[0170] Within the same series of consecutive monitoring moments, it is determined whether the order amplitude of each order amplitude sequence in the high-speed shaft order amplitude sequence group exceeds its corresponding dynamic threshold. When the order amplitude of each order amplitude sequence in the high-speed shaft order amplitude sequence group does not continuously exceed its corresponding dynamic threshold, it is determined that the order amplitude in the high-speed shaft order amplitude sequence group has not synchronously exceeded the corresponding dynamic threshold.

[0171] When the order amplitude in the connecting segment order amplitude sequence group synchronously exceeds the corresponding order amplitude dynamic threshold, and the order amplitude in the high-speed shaft order amplitude sequence group does not synchronously exceed the corresponding order amplitude dynamic threshold, the stiffness degradation indication result is determined.

[0172] In one embodiment, such as Figure 6 As shown, in step S50, the process of determining the local impact indication result is as follows:

[0173] S501: The local impact feature sequence of the corresponding main shaft connecting section near the main shaft in the local impact feature sequence group of the connecting section is determined as the local impact feature sequence of the main shaft side, and the local impact feature sequence of the corresponding main shaft connecting section near the gearbox side in the local impact feature sequence group of the connecting section is determined as the local impact feature sequence of the gearbox side.

[0174] In this embodiment, the local impact feature sequence on the spindle side is the local impact feature sequence corresponding to the signal acquisition position on the spindle connecting section near the spindle side in the local impact feature sequence group of the connecting section, and the local impact feature sequence on the gearbox side is the local impact feature sequence corresponding to the signal acquisition position on the spindle connecting section near the gearbox side in the local impact feature sequence group of the connecting section.

[0175] Specifically, the signal acquisition positions corresponding to each local impact feature sequence in the local impact feature sequence group of the connecting section are read, and each signal acquisition position is matched with the vertical and radial positions of the main bearing housing and the first-stage planetary carrier end cover of the gearbox.

[0176] When the signal acquisition position corresponding to the local impact feature sequence is the vertical radial position of the main bearing housing, the corresponding local impact feature sequence is determined as the local impact feature sequence of the main shaft side.

[0177] When the signal acquisition position corresponding to the local impact feature sequence is the vertical radial position of the first-stage planetary carrier end cover of the gearbox, the corresponding local impact feature sequence is determined as the gearbox side local impact feature sequence.

[0178] Record the signal acquisition location and monitoring time corresponding to the local impact characteristic sequence on the main shaft side and the local impact characteristic sequence on the gearbox side, respectively.

[0179] S502: Determine the changing trend of each local impact feature sequence based on the local impact characteristics of each local impact feature sequence in the main shaft side local impact feature sequence, gearbox side local impact feature sequence and high-speed shaft local impact feature sequence group at adjacent monitoring times.

[0180] In this embodiment, adjacent monitoring times are two monitoring times that are adjacent in position after being arranged in the order of monitoring times, and the trend of change is the direction of numerical change of local impact characteristics between adjacent monitoring times in the same local impact characteristic sequence.

[0181] Specifically, the local impact feature sequences in the main shaft side local impact feature sequence, gearbox side local impact feature sequence and high-speed shaft local impact feature sequence are read respectively, and two local impact features corresponding to adjacent monitoring times are selected in each local impact feature sequence in chronological order of monitoring time.

[0182] The local impact characteristics at the next monitoring time are compared with those at the previous monitoring time. When the local impact characteristics at the next monitoring time are greater than those at the previous monitoring time, the trend of change at the corresponding adjacent monitoring time is determined to be an upward trend.

[0183] When the local impact characteristics at the next monitoring time are less than those at the previous monitoring time, the trend of change at the corresponding adjacent monitoring time is determined to be a downward trend. When the local impact characteristics at two adjacent monitoring times are equal, the trend of change at the corresponding adjacent monitoring time is determined to be a stable trend.

[0184] According to the order of monitoring time, the changing trends of each local impact characteristic sequence in the main shaft side local impact characteristic sequence, gearbox side local impact characteristic sequence and high-speed shaft local impact characteristic sequence group are recorded respectively.

[0185] S503: When the trend of the local impact characteristic sequence on the main shaft side is upward over multiple consecutive monitoring times, and the trends of each local impact characteristic sequence in the gearbox side local impact characteristic sequence and the high-speed shaft local impact characteristic sequence group do not show an upward trend within the same monitoring time, the local impact indication result is determined.

[0186] In this embodiment, an upward trend within multiple consecutive monitoring times means that the change trend corresponding to every two adjacent monitoring times is an upward trend. No upward trend within the same monitoring time means that no continuous upward trend is formed within the same multiple consecutive monitoring times.

[0187] Specifically, multiple consecutive monitoring times are selected according to a preset number of consecutive times, and the changing trend of the local impact characteristic sequence on the main shaft side is read for each two adjacent monitoring times in the multiple consecutive monitoring times.

[0188] When all the read trends are upward, it is determined that the trend of the local impact characteristic sequence on the main shaft side is upward over multiple consecutive monitoring times.

[0189] Read the changing trends of each local impact characteristic sequence in the gearbox-side local impact characteristic sequence and the high-speed shaft local impact characteristic sequence group over the same consecutive monitoring times. When none of the local impact characteristic sequences in the gearbox-side local impact characteristic sequence and the high-speed shaft local impact characteristic sequence group show a continuous upward trend over the same consecutive monitoring times, it is determined that the changing trends of each corresponding local impact characteristic sequence do not show an upward trend within the same monitoring time.

[0190] When the trend of the local impact characteristic sequence on the main shaft side is upward over multiple consecutive monitoring times, and the trends of each local impact characteristic sequence in the gearbox side local impact characteristic sequence and the high-speed shaft local impact characteristic sequence group do not show an upward trend within the same monitoring time, the local impact indication result is determined.

[0191] In one embodiment, such as Figure 7 As shown, in step S60, the process of generating the crack early warning result for the spindle connection section is as follows:

[0192] S601: The wind turbine corresponding to the vibration signal group of the connecting section is identified as the target wind turbine. The connecting section order amplitude sequence group of multiple comparison wind turbines is obtained. The comparison wind turbines and the target wind turbines are located in the same wind farm, have the same model, and have matching operating conditions.

[0193] In this embodiment, the target wind turbine is the wind turbine corresponding to the vibration signal group of the connecting section, and the comparison wind turbine is other wind turbines that are located in the same wind field as the target wind turbine, have the same model, and have matching operating conditions. Matching operating conditions means that different wind turbines have the same wind speed range and power range at the corresponding monitoring time.

[0194] Specifically, the wind turbine identifier associated with the vibration signal group of the connecting section is read, and the wind turbine corresponding to the wind turbine identifier is identified as the target wind turbine.

[0195] Read the wind farm identifier and turbine model identifier corresponding to the target wind turbine, and filter other wind turbines with the same turbine model identifier from the wind farms corresponding to the wind farm identifier to obtain multiple candidate wind turbines.

[0196] For each monitoring time, the wind speed range and power range corresponding to the target wind turbine are read, and the wind speed range and power range of each candidate wind turbine at the corresponding monitoring time are also read.

[0197] When the wind speed range corresponding to the candidate wind turbine is the same as that corresponding to the target wind turbine, and the power range corresponding to the candidate wind turbine is the same as that corresponding to the target wind turbine, the corresponding candidate wind turbine is determined as the comparison wind turbine.

[0198] From the condition monitoring data of each comparative wind turbine, read the connection segment order amplitude sequence group formed according to the same generation process, and store the read connection segment order amplitude sequence group in association with the corresponding comparative wind turbine and monitoring time.

[0199] S602: Compare the order amplitude sequence of the target wind turbine with the order amplitude sequence of the connecting sections of each comparative wind turbine to determine the order variation relationship between the units.

[0200] In this embodiment, the order change relationship between units is the synchronous or asynchronous change relationship formed between the order amplitude sequence group of the connection segment of the target wind turbine and the order amplitude sequence group of the connection segment of each comparative wind turbine at a monitoring time that matches the operating conditions.

[0201] Specifically, according to the signal acquisition location, each order amplitude sequence in the connection segment order amplitude sequence group of the target wind turbine is matched with the order amplitude sequence corresponding to the same signal acquisition location in the connection segment order amplitude sequence group of each comparison wind turbine.

[0202] For each set of adjacent monitoring times that match the operating conditions, the order amplitudes in the corresponding order amplitude sequences of each comparative wind turbine are compared to determine the order change trend of each comparative wind turbine at the corresponding signal acquisition location.

[0203] When a preset number of comparative wind turbine units exhibit the same order of change trend at the same signal acquisition location and the same monitoring time, the same order of change trend is identified as the common change trend of the wind farm.

[0204] Compare the order variation trends of the target wind turbine units at the corresponding signal acquisition locations and monitoring times with the common variation trends of the wind farm. When the order variation trends of the target wind turbine units are the same as the common variation trends of the wind farm, the order variation relationship between the units is determined to be a synchronous relationship; when the order variation trends of the target wind turbine units are different from the common variation trends of the wind farm, the order variation relationship between the units is determined to be a asynchronous relationship.

[0205] S603: When the stiffness degradation indication result indicates that the main shaft connection section has undergone stiffness degradation, the local impact indication result indicates that the main shaft connection section has undergone local impact, and the order change relationship between units indicates that the target wind turbine unit and each comparison wind turbine unit have not undergone synchronous change, a crack warning result for the main shaft connection section is generated.

[0206] In this embodiment, the stiffness degradation indication result, the local impact indication result, and the order change relationship between units correspond to the same target wind turbine and the same multiple consecutive monitoring times.

[0207] Specifically, the stiffness degradation indication result and the corresponding multiple consecutive monitoring times are read to determine whether the stiffness degradation indication result has been determined. When the stiffness degradation indication result has been determined, stiffness degradation of the spindle connection section is recorded.

[0208] Read the local impact indication results and the corresponding multiple consecutive monitoring times to determine whether the local impact indication results have been confirmed. When the local impact indication results have been confirmed, record that a local impact occurred on the spindle connection section.

[0209] Read the inter-unit order change relationship of the target wind turbine unit within the same consecutive monitoring time. When the inter-unit order change relationship is asynchronous, record that the target wind turbine unit and each comparison wind turbine unit have not changed synchronously.

[0210] When stiffness degradation occurs in the main shaft connection section, local impact occurs in the main shaft connection section, and the target wind turbine and each comparison wind turbine do not change synchronously, a crack warning result for the main shaft connection section is generated. The crack warning result for the main shaft connection section is then associated and stored with the target wind turbine, the corresponding multiple consecutive monitoring times, stiffness degradation indication results, and local impact indication results.

[0211] In one embodiment, such as Figure 8 As shown, after step S60, the process of generating the crack early warning result for the spindle connection section also includes:

[0212] S70: Determine the main shaft side order amplitude sequence from the connecting segment order amplitude sequence group that corresponds to the same signal acquisition position as the main shaft side local impact characteristic sequence.

[0213] In this embodiment, the order amplitude sequence on the main shaft side is the order amplitude sequence in the connecting segment order amplitude sequence group that has the same signal acquisition position as the local impact feature sequence on the main shaft side.

[0214] Specifically, the signal acquisition locations associated with the local impact feature sequence on the main shaft side are read, and the read signal acquisition locations are determined as the signal acquisition locations to be matched.

[0215] Read the signal acquisition positions associated with each order amplitude sequence in the connection segment order amplitude sequence group respectively, and compare the signal acquisition positions associated with each order amplitude sequence with the signal acquisition positions to be matched.

[0216] When the signal acquisition location associated with the order amplitude sequence is the same as the signal acquisition location to be matched, the corresponding order amplitude sequence is determined as the main axis order amplitude sequence, and the correspondence between the signal acquisition locations of the main axis order amplitude sequence and the main axis local impact feature sequence is recorded.

[0217] S80: Determine the synergistic relationship between the two features based on the changing trends of the main shaft side order amplitude sequence and the main shaft side local impact characteristic sequence at the same monitoring time.

[0218] In this embodiment, the dual-feature coordinated change relationship is a synchronous or asynchronous change relationship formed between the change trends of the main axis-side order amplitude sequence and the main axis-side local impact feature sequence within the same monitoring time.

[0219] Specifically, the monitoring times corresponding to the main shaft side order amplitude sequence and the main shaft side local impact characteristic sequence are read, and the same monitoring time in the two sequences is selected.

[0220] Following the chronological order of monitoring times, the order amplitudes of adjacent monitoring times in the principal axis order amplitude sequence are compared sequentially. When the order amplitude of a later monitoring time is greater than that of a previous monitoring time, the trend of change for the corresponding adjacent monitoring times is determined to be an upward trend; when the order amplitude of a later monitoring time is less than or equal to that of a previous monitoring time, the trend of change for the corresponding adjacent monitoring times is determined to be a non-upward trend.

[0221] Read the changing trend of the local impact characteristic sequence on the main shaft side at the same adjacent monitoring time, and compare the changing trend of the order amplitude sequence on the main shaft side with the changing trend of the local impact characteristic sequence on the main shaft side.

[0222] When the change trends of two sequences are both upward at the same adjacent monitoring time, the dual-feature coordinated change relationship at the corresponding adjacent monitoring time is determined as a synchronous change relationship. When the change trend of at least one of the two sequences is not upward, the dual-feature coordinated change relationship at the corresponding adjacent monitoring time is determined as an asynchronous change relationship.

[0223] Record the dual-feature coordinated change relationship corresponding to each adjacent monitoring time in chronological order.

[0224] S90: When the dual-feature synergistic change relationship characterizes the order amplitude sequence of the main shaft side and the local impact characteristic sequence of the main shaft side to form an upward trend synchronously within multiple consecutive monitoring times, and both the stiffness degradation indication result and the local impact indication result characterize anomalies, a crack early warning result for the main shaft connection section is generated.

[0225] In this embodiment, the anomaly is characterized by stiffness degradation indication or local impact indication, which has been determined and corresponds to multiple consecutive monitoring times. The synchronous upward trend is formed when the dual-feature synergistic change relationship between each two adjacent monitoring times in the multiple consecutive monitoring times is a synchronous change relationship.

[0226] Specifically, multiple consecutive monitoring times are selected according to a preset number of consecutive times, and the dual-feature collaborative change relationship corresponding to every two adjacent monitoring times in the multiple consecutive monitoring times is read.

[0227] When all the dual-feature coordinated change relationships read are synchronous change relationships, the change trends of the principal axis side order amplitude sequence and the principal axis side local impact feature sequence are read in multiple consecutive monitoring times.

[0228] When both the principal axis-side order amplitude sequence and the principal axis-side local impact characteristic sequence show an upward trend over multiple consecutive monitoring periods, the synergistic change relationship of the two features is determined to characterize the synchronous upward trend of the principal axis-side order amplitude sequence and the principal axis-side local impact characteristic sequence.

[0229] Read the stiffness degradation indication results and local impact indication results corresponding to multiple consecutive monitoring times. When both the stiffness degradation indication results and the local impact indication results have been determined, it is determined that both the stiffness degradation indication results and the local impact indication results represent anomalies.

[0230] When the dual-feature synergistic change relationship indicates that the principal shaft side order amplitude sequence and the principal shaft side local impact characteristic sequence simultaneously form an upward trend, and both the stiffness degradation indication result and the local impact indication result indicate anomalies, a crack early warning result for the principal shaft connection segment is generated, and the crack early warning result for the principal shaft connection segment is associated and stored with the corresponding consecutive multiple monitoring times, the principal shaft side order amplitude sequence, the principal shaft side local impact characteristic sequence, the stiffness degradation indication result, and the local impact indication result.

[0231] In one embodiment, such as Figure 9 As shown, in step S603, the process of determining the order change relationship between units is as follows:

[0232] S6031: Determine the target order change trend and multiple comparison order change trends based on the order amplitude sequence groups of the connecting segments of the target wind turbine and each comparative wind turbine.

[0233] In this embodiment, the target order change trend is the overall change trend of the connection segment order amplitude sequence group of the target wind turbine at adjacent monitoring times, and the comparison order change trend is the overall change trend of the connection segment order amplitude sequence group of each comparison wind turbine at adjacent monitoring times.

[0234] Specifically, according to the signal acquisition location, the order amplitude of each order amplitude sequence in the connection segment order amplitude sequence group of the target wind turbine is read at adjacent monitoring times, and the order amplitude of the later monitoring time is compared with the order amplitude of the previous monitoring time to determine the change trend of each order amplitude sequence.

[0235] When the order amplitude sequences of the target wind turbine have the same trend at the same adjacent monitoring time, the same trend is determined as the target order trend at the corresponding adjacent monitoring time. When the trends of the order amplitude sequences are different, the target order trend at the corresponding adjacent monitoring time is determined as the asynchronous trend.

[0236] For each comparison wind turbine, the changing trend of each order amplitude sequence in the corresponding connection segment order amplitude sequence group at adjacent monitoring times is determined in the same way. When the order amplitude sequences of the same comparison wind turbine have the same changing trend, the same changing trend is determined as the corresponding comparison order changing trend. When the changing trends of each order amplitude sequence are different, the corresponding comparison order changing trend is determined as the asynchronous changing trend.

[0237] S6032: When multiple comparison order trends change synchronously, the common trend of wind field change is determined based on the trends of multiple comparison orders.

[0238] In this embodiment, the common variation trend of the wind field is the comparative order variation trend that multiple comparative wind turbines share at the same monitoring time when their operating conditions are matched.

[0239] Specifically, according to the monitoring time and the corresponding wind speed and power range, the changing trends of multiple comparison orders are classified, and the changing trends of multiple comparison orders corresponding to the same monitoring time, the same wind speed range, and the same power range are read.

[0240] The number of comparative wind turbines corresponding to upward, downward, and stable trends is counted separately. When the number of comparative wind turbines corresponding to any trend reaches a preset number, the trends of multiple comparative orders are determined to change synchronously at the corresponding monitoring time.

[0241] The common trend of the comparison order change among multiple wind turbine units that have reached a preset number is determined as the common trend of wind field change at the corresponding monitoring time.

[0242] Record the common trends of wind field changes in chronological order of monitoring time, and associate and store the common trends of wind field changes with the corresponding wind speed range and power range.

[0243] S6033: Compare the target order change trend with the common change trend of the wind field. When the target order change trend and the common change trend of the wind field are not synchronized, determine the order change relationship between the units to indicate that the target wind turbine and each comparative wind turbine have not changed synchronously.

[0244] Specifically, the monitoring time, wind speed range, and power range associated with the target order change trend are read, and the corresponding common wind field change trends are queried based on the read monitoring time, wind speed range, and power range.

[0245] Read the change states corresponding to the target order change trend and the common wind field change trend, and compare the two change states. When the two change states are the same, it is determined that the target order change trend and the common wind field change trend are synchronized; when the two change states are different, it is determined that the target order change trend and the common wind field change trend are not synchronized.

[0246] When the target order change trend is not synchronized with the common change trend of the wind field, the comparative wind turbines that form the common change trend of the wind field are read, and the order change relationship between the units is determined to indicate that the target wind turbine and each comparative wind turbine have not changed synchronously.

[0247] It should be understood that the sequence number of each step in the above embodiments does not imply the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of this application.

[0248] In one embodiment, a wind turbine main shaft connection section crack early warning device is provided, which corresponds one-to-one with the wind turbine main shaft connection section crack early warning method in the above embodiments. For example... Figure 10 As shown, the wind turbine main shaft connection section crack early warning device includes a signal acquisition module, an order amplitude sequence group generation module, a local impact characteristic sequence group generation module, a stiffness degradation indication result determination module, a local impact indication result determination module, and a crack early warning result generation module.

[0249] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the above-described division of functional units and modules is used as an example. In practical applications, the above functions can be assigned to different functional units and modules as needed, that is, the internal structure of the device can be divided into different functional units or modules to complete all or part of the functions described above.

[0250] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit it. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications 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 included within the protection scope of this application.

Claims

1. A method for early warning of cracks in the connecting section of a wind turbine main shaft, characterized in that, The method includes: Vibration signal groups of connecting sections, vibration signal groups of high-speed shafts, and high-speed shaft rotational speed pulse signals are acquired at multiple monitoring times. The vibration signal groups of connecting sections are collected from both sides of the connecting section of the shaft, and the vibration signal groups of high-speed shafts are collected from both ends of the high-speed shaft. Using the high-speed shaft rotational speed pulse signal as an angular reference, the vibration signals in the connecting section vibration signal group and the high-speed shaft vibration signal group are resampled in the angular domain, the order amplitude is extracted and arranged in the order of the monitoring time to obtain the connecting section order amplitude sequence group and the high-speed shaft order amplitude sequence group respectively. The vibration signals in the connecting section vibration signal group and the high-speed shaft vibration signal group are subjected to frequency band filtering, local impact features are extracted and arranged in chronological order of the monitoring time to obtain the connecting section local impact feature sequence group and the high-speed shaft local impact feature sequence group, respectively. The stiffness degradation indication result is determined based on the synchronous changes within the connecting segment order amplitude sequence group and the difference changes between the connecting segment order amplitude sequence group and the high-speed shaft order amplitude sequence group. The local impact indication result is determined based on the differences within the local impact characteristic sequence group of the connecting section and the differences between the local impact characteristic sequence group of the connecting section and the local impact characteristic sequence group of the high-speed shaft. Based on the stiffness degradation indication result and the local impact indication result, a crack early warning result for the main shaft connection section is generated.

2. The method for early warning of cracks in the connecting section of a wind turbine main shaft according to claim 1, characterized in that, The vibration signal group of the connecting section and the vibration signal group of the high-speed shaft are synchronously acquired in the radial vertical direction. The sampling frequency of the vibration signal group of the connecting section is lower than that of the vibration signal group of the high-speed shaft. The single sampling duration of the vibration signal group of the connecting section is greater than that of the vibration signal group of the high-speed shaft.

3. The method for early warning of cracks in the connecting section of a wind turbine main shaft according to claim 1, characterized in that, The generation process of the connecting segment order amplitude sequence group and the high-speed shaft order amplitude sequence group is as follows: The equal-angle sampling position is determined based on the high-speed shaft rotation pulse signal; According to the aforementioned equal-angle sampling positions, the vibration signals in the connecting section vibration signal group and the high-speed shaft vibration signal group are interpolated and resampled respectively, and the interpolated and resampled vibration signals are synchronously averaged. The first-order amplitude of the high-speed shaft is extracted from the vibration signal after synchronous averaging. The first-order amplitude of the high-speed shaft is arranged in chronological order according to the monitoring time to obtain the sequence group of the connecting segment first-order amplitude and the sequence group of the high-speed shaft first-order amplitude.

4. The method for early warning of cracks in the connecting section of a wind turbine main shaft according to claim 1, characterized in that, The generation process of the local impact feature sequence group of the connecting section and the local impact feature sequence group of the high-speed shaft is as follows: The vibration signals corresponding to the monitoring time in the vibration signal group of the connecting section and the vibration signal group of the high-speed shaft are respectively filtered by frequency band, and the kurtosis of each vibration signal after frequency band filtering is calculated. The kurtosis is determined as a local impact feature. According to the signal acquisition location and monitoring time corresponding to the local impact characteristics, the local impact characteristics are arranged into the connection segment local impact characteristic sequence group and the high-speed shaft local impact characteristic sequence group, respectively.

5. The method for early warning of cracks in the connecting section of a wind turbine main shaft according to claim 1, characterized in that, The process for determining the stiffness degradation indication result is as follows: Obtain the wind speed and power corresponding to the monitoring time, and determine the wind speed range and power range corresponding to each monitoring time based on the wind speed and power. Based on the historical order amplitude values ​​within each wind speed and power range, dynamic threshold values ​​for each order amplitude sequence are established for each order amplitude sequence in the connecting segment order amplitude sequence group and the high-speed axis order amplitude sequence group. The order amplitude at each monitoring time is compared with the dynamic threshold of the order amplitude for the corresponding wind speed range and power range. When the order amplitude in the connecting segment order amplitude sequence group synchronously exceeds the corresponding dynamic threshold of the order amplitude at multiple consecutive monitoring times, and the order amplitude in the high-speed shaft order amplitude sequence group does not synchronously exceed the corresponding dynamic threshold of the order amplitude, the stiffness degradation indication result is determined.

6. The method for early warning of cracks in the connecting section of a wind turbine main shaft according to claim 1, characterized in that, The process for determining the local impact indication result is as follows: The local impact feature sequence of the corresponding main shaft connecting segment near the main shaft in the local impact feature sequence group of the connecting segment is determined as the local impact feature sequence of the main shaft side, and the local impact feature sequence of the corresponding main shaft connecting segment near the gearbox side in the local impact feature sequence group of the connecting segment is determined as the local impact feature sequence of the gearbox side. Based on the local impact characteristics of each local impact characteristic sequence in the main shaft side local impact characteristic sequence, the gearbox side local impact characteristic sequence, and the high-speed shaft local impact characteristic sequence group at adjacent monitoring times, the changing trend of each local impact characteristic sequence is determined; When the change trend of the local impact characteristic sequence on the main shaft side is upward over multiple consecutive monitoring times, and the change trends of each local impact characteristic sequence in the gearbox side and the high-speed shaft local impact characteristic sequence group do not show an upward trend within the same monitoring time, the local impact indication result is determined.

7. The method for early warning of cracks in the connecting section of a wind turbine main shaft according to claim 1, characterized in that, The process for generating the early warning result of the main shaft connection section crack is as follows: The wind turbine corresponding to the vibration signal group of the connecting section is identified as the target wind turbine. Multiple comparison wind turbines are obtained, and the comparison wind turbines and the target wind turbines are located in the same wind farm, have the same model and match the operating conditions. By comparing the order amplitude sequence of the connection segment of the target wind turbine with the order amplitude sequence of the connection segment of each of the comparison wind turbines, the order variation relationship between the turbines is determined. When the stiffness degradation indication result indicates that the main shaft connection section has undergone stiffness degradation, the local impact indication result indicates that the main shaft connection section has undergone local impact, and the inter-unit order change relationship indicates that the target wind turbine and each of the comparison wind turbines have not undergone synchronous change, a crack warning result for the main shaft connection section is generated.

8. The method for early warning of cracks in the connecting section of a wind turbine main shaft according to claim 7, characterized in that, The process of generating the early warning result for the spindle connection section crack also includes: From the connected segment order amplitude sequence group, determine the main shaft side order amplitude sequence that corresponds to the same signal acquisition position as the main shaft side local impact feature sequence; The relationship between the two features is determined based on the changing trends of the main shaft side order amplitude sequence and the main shaft side local impact feature sequence at the same monitoring time. When the dual-feature synergistic change relationship indicates that the order amplitude sequence of the main shaft side and the local impact characteristic sequence of the main shaft side synchronously form an upward trend within multiple consecutive monitoring times, and when both the stiffness degradation indication result and the local impact indication result indicate anomalies, the crack warning result of the main shaft connection segment is generated.

9. The method for early warning of cracks in the connecting section of a wind turbine main shaft according to claim 7, characterized in that, The process for determining the order change relationship between the units is as follows: Based on the target wind turbine and the sequence of order amplitude values ​​of the connecting segments of each of the comparison wind turbines, the target order variation trend and multiple comparison order variation trends are determined respectively. When multiple comparison order change trends change synchronously, the common change trend of the wind field is determined based on the multiple comparison order change trends; By comparing the target order change trend with the common change trend of the wind field, when the target order change trend and the common change trend of the wind field are not synchronized, the order change relationship between the units is determined to indicate that the target wind turbine and each of the comparison wind turbines have not changed synchronously.

10. A crack early warning device for the connecting section of a wind turbine main shaft, characterized in that, The device includes: The signal acquisition module is used to acquire the vibration signal group of the connecting section, the vibration signal group of the high-speed shaft, and the high-speed shaft rotational speed pulse signal at multiple monitoring times. The vibration signal group of the connecting section is collected from both sides of the connecting section of the shaft, and the vibration signal group of the high-speed shaft is collected from both ends of the high-speed shaft. The order amplitude sequence generation module is used to perform angular domain resampling on the vibration signals in the connecting section vibration signal group and the high-speed shaft vibration signal group, using the high-speed shaft rotation speed pulse signal as an angular reference, extracting the order amplitude, and arranging them in the order of the monitoring time to obtain the connecting section order amplitude sequence group and the high-speed shaft order amplitude sequence group respectively. The local impact feature sequence generation module is used to perform frequency band filtering on the vibration signals in the connecting section vibration signal group and the high-speed shaft vibration signal group, extract local impact features, and arrange them in the order of the monitoring time to obtain the connecting section local impact feature sequence group and the high-speed shaft local impact feature sequence group, respectively. The stiffness degradation indication result determination module is used to determine the stiffness degradation indication result based on the synchronous changes within the connecting segment order amplitude sequence group and the difference changes between the connecting segment order amplitude sequence group and the high-speed shaft order amplitude sequence group. The local impact indication result determination module is used to determine the local impact indication result based on the difference changes within the local impact feature sequence group of the connecting section and the difference changes between the local impact feature sequence group of the connecting section and the local impact feature sequence group of the high-speed shaft. The crack early warning result generation module is used to generate a crack early warning result for the main shaft connection section based on the stiffness degradation indication result and the local impact indication result.

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