An online measurement and control system and method for bolt preload of wind turbine units

Abstract

This application discloses an online measurement and control system and method for bolt preload in wind turbine generators, relating to the field of safety monitoring and fault diagnosis technology for wind power equipment. The system includes: an ultrasonic probe for transmitting ultrasonic pulses into the bolt under test and receiving echo signals reflected from the end face, as well as collecting ambient temperature data of the bolt; a bolt monitoring host for collecting echo signals and performing analog-to-digital conversion and measuring echo time difference data; a communication link including switches and wireless bridge devices deployed inside the wind turbine hub and at the base of the tower, for transmitting the outputs of each bolt monitoring host to a monitoring server via the wind farm ring network fiber optic cable; and a monitoring server connected to the bolt monitoring host via the communication link for performing temperature compensation calculations based on the received echo time difference data and temperature data to obtain the bolt preload value, and performing trend analysis and threshold alarms.

Description

Technical Field

[0001] This application relates to the field of safety monitoring and fault diagnosis technology for wind power generation equipment, and in particular to an online measurement and control system and method for bolt preload of wind turbine units. Background Technology

[0002] Currently, the industry's detection technology for loose wind turbine bolts has the following limitations: 1) The traditional torque wrench sampling method relies on manual periodic climbing of the tower for re-tightening, which is not only labor-intensive and has a high risk factor of working at height, but also has a blind spot of "loosening after tightening" and cannot reflect the real axial force state inside the bolt in real time; 2) Image detection methods based on machine vision or deep learning can identify obvious bolt rotation or breakage, but they are powerless against early preload decay and microscopic plastic deformation inside the bolt that are invisible to the naked eye. 3) Existing ultrasonic axial force measurement technology is mostly used for single-point offline testing in the automotive or aerospace fields. Directly applying it to wind turbines for large-scale online monitoring faces significant challenges: the wind turbine hub is a continuously rotating component, and traditional wired transmission is difficult to cross the rotating slip ring; at the same time, the drastic temperature differences in the wind field environment will severely interfere with the propagation speed of ultrasonic waves inside the metal, leading to large deviations in axial force calculations.

[0003] Therefore, the wind power industry urgently needs an online measurement and control system for bolt preload that can adapt to strong electromagnetic interference, drastic temperature differences, and the special structure of rotating components, in order to completely change the passive situation of traditional post-maintenance and realize proactive safety early warning and closed-loop control of wind power bolts. Summary of the Invention

[0004] The purpose of this application is to provide an online measurement and control system and method for bolt preload of wind turbine units, which can realize real-time, accurate, online monitoring and closed-loop control of bolt preload in key parts of wind turbine units.

[0005] To achieve the above objectives, this application provides the following solution: In a first aspect, this application provides an online measurement and control system for the preload of wind turbine bolts, comprising: Several ultrasonic probes are installed on the end face of the bolt being tested to emit ultrasonic pulses into the bolt and receive the echo signals reflected from the end face, as well as to collect the ambient temperature data of the bolt being tested. Several bolt monitoring hosts are connected to the ultrasonic probe for acquiring the echo signal and performing analog-to-digital conversion and measuring the echo time difference data of the echo signal. The communication link includes switches and wireless bridge devices deployed inside the wind turbine hub and at the base of the tower, respectively, for transmitting the output of each bolt monitoring host to the monitoring server through the wind farm ring network fiber optic cable; The monitoring server is connected to the bolt monitoring host through the communication link. It is used to perform temperature compensation calculation based on the received echo time difference data and temperature data, obtain the bolt preload value, and perform trend analysis and threshold alarm.

[0006] Secondly, this application provides a method for online measurement and control of bolt preload in wind turbine units, including: S1: Control the ultrasonic probe to emit ultrasonic pulses into the bolt being tested, and receive the echo signal reflected from the end face of the bolt being tested, while simultaneously collecting the ambient temperature data of the bolt being tested. S2: Control the bolt monitoring host to collect echo signals, and perform analog-to-digital conversion and echo time difference data measurement on the echo signals; S3: Control the communication link to transmit the output of each bolt monitoring host to the monitoring server; S4: The control and monitoring server performs temperature compensation calculations on the received echo time difference data and ambient temperature data to obtain the bolt preload value; S5: The control and monitoring server performs trend analysis and threshold alarms on bolt preload values. The online monitoring platform software presents the axial force distribution of all uniformly distributed bolts in a single flange face in real time in the form of radar charts and bar charts, and tracks the axial force change trend of a single bolt under the conditions of gusts of wind, speed and power increase in line chart.

[0007] According to the specific embodiments provided in this application, the following technical effects are disclosed: This application provides an online measurement and control system and method for bolt preload in wind turbine generators. Through the collaborative operation of an ultrasonic probe and a bolt monitoring host, real-time and accurate sensing of bolt preload in wind turbine generators is achieved. Regarding data transmission, communication links are deployed for bolts at different locations within the wind turbine generator. Several bolt monitoring hosts are installed at various locations on the wind turbine generator, enabling non-contact transmission of signals across different locations, overcoming the technical bottlenecks of traditional wired transmission in rotating environments. The monitoring server can perform temperature compensation calculations based on echo time difference data and temperature data to derive the bolt preload value, and perform trend analysis and threshold alarms, forming a closed-loop control to ensure the accuracy and consistency of bolt preload during tightening and operation. Attached Figure Description

[0008] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0009] Figure 1 This is a topology diagram of an online measurement and control system for bolt preload of a wind turbine provided in one embodiment of this application.

[0010] Figure 2 This is a schematic flowchart of an online measurement and control method for bolt preload of a wind turbine provided in an embodiment of this application.

[0011] Figure 3 This is a schematic diagram of a computer device structure provided in an embodiment of this application. Detailed Implementation

[0012] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0013] In recent years, the global energy structure transformation has accelerated, and the wind power industry has experienced explosive growth. Statistics show that the global installed wind power capacity has exceeded 1.1 TW, with China's installed capacity approaching 580 GW, ranking first in the world. To achieve the "dual carbon" goal, offshore wind power and large-scale onshore wind farm construction are in full swing, and wind turbines are showing a significant trend towards larger sizes. However, with the increase in blade length and tower height, the load on key connection parts of the turbine has increased dramatically. Wind farm operation and maintenance costs now account for 20-25% of the levelized cost of electricity (LCOE), with equipment aging and connector failure being the main causes of unplanned downtime. High-strength connecting bolts are core components that transmit enormous mechanical loads between the wind turbine blade root and the hub and tower flange sections. During their 20-year service life, these bolts are subjected to harsh environments of extreme temperature differences, strong gusts, and alternating stress, making them prone to preload decay, loosening, and ultimately fatigue cracks or even breakage. Accident cases show that broken tower flange bolts can lead to tower collapse, while failure of blade root bolts directly causes blade detachment. Statistics indicate that over 80% of bolt breakage accidents are related to insufficient preload or uneven stress. Therefore, early measurement and control diagnosis of bolt preload are crucial for ensuring wind power safety.

[0014] Therefore, the purpose of this application is to provide an online measurement and control system and method for bolt preload of wind turbine generators, which can realize real-time, accurate, online monitoring and closed-loop control of bolt preload in key parts of wind turbine generators. To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the application will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0015] Example 1 like Figure 1 As shown, this embodiment provides an online measurement and control system for the preload of wind turbine bolts, including: Several ultrasonic probes are installed on the end face of the bolt being tested to emit ultrasonic pulses into the bolt and receive the echo signals reflected from the end face, as well as to collect the ambient temperature data of the bolt being tested. Several bolt monitoring hosts are connected to the ultrasonic probe for acquiring the echo signal and performing analog-to-digital conversion and measuring the echo time difference data of the echo signal. The communication link includes switches and wireless bridge devices deployed inside the wind turbine hub and at the bottom of the wind turbine tower, respectively, used to transmit the output of each bolt monitoring host to the monitoring server through the wind farm ring network fiber optic cable. The monitoring server is connected to the bolt monitoring host through the communication link. It is used to perform temperature compensation calculations based on the received echo time difference data and ambient temperature data, obtain the bolt preload value, and perform trend analysis and threshold alarms.

[0016] In some embodiments, such as Figure 1 As shown, the ultrasonic probes installed on the wind turbine are all end-face ultrasonic probes with integrated temperature sensors. They support temperature compensation for the sound velocity and deformation measurements of each tested bolt within an ambient temperature range of -40℃ to +70℃, eliminating the interference of extreme temperature differences on axial force measurement. Specifically, the integrated temperature sensor monitors the ambient temperature of the tested bolt in real time. Based on this temperature data, the measured values ​​of sound velocity and deformation are corrected, effectively eliminating the interference of extreme temperature differences on axial force measurement and ensuring the accuracy and reliability of axial force measurement results under different temperature conditions.

[0017] In some embodiments, such as Figure 1As shown, the booster station monitoring server has a built-in bolt load calculation model. This model is used to: record the initial time difference T0 of the bolt in its free state and the real-time time difference T1 in its tightened state, and calculate the time difference change ΔT based on the initial time difference T0 and the real-time time difference T1; it is also used to: calculate the deformation ΔL of the bolt based on the mechanical longitudinal wave propagation velocity; and it is also used to: calculate the deformation ΔL of the bolt based on the elastic modulus E, cross-sectional area S, and clamping length L of the bolt, using the formula... Calculate the bolt preload value F of the bolt being tested.

[0018] For example, in the monitoring of tower flange bolts of a 1.5MW wind turbine, the initial time difference T0 measured by the ultrasonic probe for a certain bolt in its free state was 5.20μs. After the bolt was tightened, the real-time monitored time difference T1 was 5.28μs, from which the time difference change ΔT was calculated to be 0.08μs. It is known that the bolt is an 8.8 grade M30 high-strength bolt with an elastic modulus E of 206GPa and a calculated cross-sectional area S of 706.86mm². 2 The clamping length L is 200mm. Assuming the propagation speed of the mechanical longitudinal wave in the bolt material is 5900m / s, according to the deformation ΔL = v × ΔT (where v is the speed of sound and ΔT is the change in time difference), ΔL = 5900m / s × 0.08 × 10⁻⁶. -6 s = 0.000472m = 0.472mm. Substituting the above parameters into the formula F = (E × S / L) × ΔL, we get F = (206 × 10 9 Pa×706.86×10 -6 m 2 (0.2m)×0.000472m, and through step-by-step calculation, F≈343647N is obtained, that is, the current preload of the bolt is about 343.6kN. This value can be compared with the design preload range of this type of bolt to determine whether it is in normal working condition.

[0019] In some embodiments, such as Figure 1 As shown, the bolt monitoring host is used to perform multi-channel synchronous real-time measurement, and the single-channel data measurement frequency in the multi-channel synchronous real-time measurement is not less than 1Hz. Furthermore, the system has an automatic self-test function after power-on and can issue alarms for hardware malfunctions or errors.

[0020] Specifically, the software functions of the bolt monitoring host include at least: measuring bolt preload, calculating and tracking bolt load, trend tracking and early warning; and recording and storing channel number, waveform, echo time, sound time difference, elongation, preload, ambient temperature and measurement time; and connecting to the upper control system via Ethernet to transmit data.

[0021] When the bolt being tested is a blade root bolt inside the wind turbine hub, which is a rotating component, the bolt monitoring host is installed inside the wind turbine hub; the communication link uses a PoE-powered dedicated wireless bridge for monitoring, which transmits the signal from the bolt monitoring host inside the wind turbine hub across the rotating component to the switch at the bottom of the wind turbine tower in a non-contact manner.

[0022] When the bolts being tested are tower flange bolts, each of the bolt monitoring hosts is deployed on each flange surface of the wind turbine tower. The ultrasonic probes of each flange surface are connected to the corresponding bolt monitoring host via signal lines that run in a ring along the flange surface, and then connected to the switch at the bottom of the wind turbine tower via network cables.

[0023] The monitoring server is equipped with online monitoring platform software, which is used to present the axial force distribution of all uniformly distributed bolts in a single flange face in real time in the form of radar charts and bar charts; and to track the axial force change trend of a single bolt under the conditions of gusts of wind, rotation speed and power increase in the form of line charts.

[0024] Monitoring servers or edge computing units deployed at the front end of the wind turbine can feed back the real-time monitoring results of axial force during the bolt tightening process to the wind turbine control system or hydraulic fastening equipment to form a closed-loop control, so as to ensure the accuracy and consistency of bolt preload during tightening and operation.

[0025] In addition, the preload measurement and control algorithm further includes multi-sensor data fusion and edge computing: in addition to ultrasound, angle and temperature sensors are integrated to cross-verify the preload status and reduce single sensor errors. An edge computing unit is built into the tower to preprocess and warn data in real time, so as to reduce the amount of uplink data and improve the response speed.

[0026] Example 2 like Figure 2 As shown, this embodiment provides a method for online measurement and control of bolt preload in wind turbine units, including: S1: Control the ultrasonic probe to emit ultrasonic pulses into the bolt being tested, and receive the echo signal reflected from the end face of the bolt being tested, while simultaneously collecting the ambient temperature data of the bolt being tested. S2: Control the bolt monitoring host to collect echo signals, and perform analog-to-digital conversion and echo time difference data measurement on the echo signals; S3: Control the communication link to transmit the output of each bolt monitoring host to the monitoring server; S4: The control and monitoring server performs temperature compensation calculations on the received echo time difference data and ambient temperature data to obtain the bolt preload value; S5: The control and monitoring server performs trend analysis and threshold alarms on bolt preload values. The online monitoring platform software presents the axial force distribution of all uniformly distributed bolts in a single flange face in real time in the form of radar charts and bar charts, and tracks the axial force change trend of a single bolt under the conditions of gusts of wind, speed and power increase in line chart.

[0027] Specifically, S4 includes: based on Calculate the bolt preload value of the bolt being tested; In the formula, F is the bolt preload, E is the elastic modulus of the bolt being tested, S is the cross-sectional area of ​​the bolt being tested, L is the clamping length of the bolt being tested, and ΔL is the deformation of the bolt being tested.

[0028] In one exemplary embodiment, a computer device is provided, which may be a server or a terminal, and its internal structure diagram may be as follows. Figure 3 As shown, the computer device includes a processor, memory, input / output (I / O) interfaces, and a communication interface. The processor, memory, and I / O interfaces are connected via a system bus, and the communication interface is also connected to the system bus via the I / O interfaces. The processor provides computational and control capabilities. The memory includes non-volatile storage media and internal memory. The non-volatile storage media stores the operating system, computer programs, and a database. The internal memory provides the environment for the operation of the operating system and computer programs stored in the non-volatile storage media. The database stores the bolt preload values ​​of the measured bolts. The I / O interfaces are used for information exchange between the processor and external devices. The communication interface is used for communication with external terminals via a network connection. When the computer program is executed by the processor, it implements an online measurement and control method for the bolt preload of a wind turbine.

[0029] Those skilled in the art will understand that Figure 3 The structure shown is merely a block diagram of a portion of the structure related to the present application and does not constitute a limitation on the computer device to which the present application is applied. Specific computer devices may include more or fewer components than those shown in the figure, or combine certain components, or have different component arrangements.

[0030] In one exemplary embodiment, a computer device is also provided, including a memory and a processor, wherein the memory stores a computer program, and the processor executes the computer program to implement the steps in the above-described method embodiments.

[0031] In one exemplary embodiment, a computer-readable storage medium is provided storing a computer program that, when executed by a processor, implements the steps in the above-described method embodiments.

[0032] It should be noted that the user information (including but not limited to user device information, user personal information, etc.) and data (including but not limited to data used for analysis, data stored, data displayed, etc.) involved in this application are all information and data authorized by the user or fully authorized by all parties, and the collection, use and processing of the relevant data must comply with relevant regulations.

[0033] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The computer program can be stored in a non-volatile computer-readable storage medium. When executed, the computer program can include the processes of the embodiments described above. Any references to memory, databases, or other media used in the embodiments provided in this application can include at least one of non-volatile and volatile memory. Non-volatile memory can include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory can include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can take many forms, such as Static Random Access Memory (SRAM) or Dynamic Random Access Memory (DRAM).

[0034] The databases involved in the embodiments provided in this application may include at least one type of relational database and non-relational database. Non-relational databases may include, but are not limited to, blockchain-based distributed databases. The processors involved in the embodiments provided in this application may be general-purpose processors, central processing units, graphics processing units, digital signal processors, programmable logic devices, quantum computing-based data processing logic devices, etc., and are not limited to these.

[0035] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0036] This document uses specific examples to illustrate the principles and implementation methods of this application. The descriptions of the above embodiments are only for the purpose of helping to understand the methods and core ideas of this application. Furthermore, those skilled in the art will recognize that, based on the ideas of this application, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. An online measurement and control system for bolt preload of a wind turbine generator, characterized in that, include: Several ultrasonic probes are installed on the end face of the bolt being tested to emit ultrasonic pulses into the bolt and receive the echo signals reflected from the end face, as well as to collect the ambient temperature data of the bolt being tested. Several bolt monitoring hosts are connected to the ultrasonic probe for acquiring the echo signal and performing analog-to-digital conversion and measuring the echo time difference data of the echo signal. The communication link includes switches and wireless bridge devices deployed inside the wind turbine hub and at the bottom of the wind turbine tower, respectively, used to transmit the output of each bolt monitoring host to the monitoring server through the wind farm ring network fiber optic cable. The monitoring server is connected to the bolt monitoring host through the communication link. It is used to perform temperature compensation calculations based on the received echo time difference data and ambient temperature data, obtain the bolt preload value, and perform trend analysis and threshold alarms.

2. The online measurement and control system for bolt preload of a wind turbine as described in claim 1, characterized in that, The ultrasonic probe is an end-face ultrasonic probe with an integrated temperature sensor, used to perform temperature compensation on the sound velocity and deformation measurement results of each tested bolt within an ambient temperature range of -40℃ to +70℃.

3. The online measurement and control system for bolt preload of a wind turbine as described in claim 1, characterized in that, The monitoring server has a built-in bolt load calculation model. This model is used to: record the initial time difference T0 of the bolt in its free state and the real-time time difference T1 in its tightened state, and calculate the time difference change ΔT based on the initial time difference T0 and the real-time time difference T1; it is also used to: calculate the deformation ΔL of the bolt based on the mechanical longitudinal wave propagation velocity; and it is also used to: calculate the deformation ΔL of the bolt based on the elastic modulus E, cross-sectional area S, and clamping length L of the bolt, using the formula... Calculate the bolt preload value F of the bolt being tested.

4. The online measurement and control system for bolt preload of a wind turbine as described in claim 1, characterized in that, The bolt monitoring host is used to perform multi-channel synchronous real-time measurement, and the single-channel data measurement frequency in the multi-channel synchronous real-time measurement is not less than 1Hz.

5. The online measurement and control system for bolt preload of a wind turbine as described in claim 1, characterized in that, When the bolt being tested is a blade root bolt inside the wind turbine hub, which is a rotating component, the bolt monitoring host is installed inside the wind turbine hub; the communication link uses a PoE-powered dedicated wireless bridge for monitoring, which transmits the signal from the bolt monitoring host inside the wind turbine hub across the rotating component to the switch at the bottom of the wind turbine tower in a non-contact manner.

6. The online measurement and control system for bolt preload of a wind turbine as described in claim 1, characterized in that, When the bolts being tested are tower flange bolts, each of the bolt monitoring hosts is deployed on each flange surface of the wind turbine tower. The ultrasonic probes of each flange surface are connected to the corresponding bolt monitoring host via signal lines that run in a ring along the flange surface, and then connected to the switch at the bottom of the wind turbine tower via network cables.

7. The online measurement and control system for bolt preload of a wind turbine as described in claim 1, characterized in that, The monitoring server is equipped with online monitoring platform software, which is used to present the axial force distribution of all uniformly distributed bolts in a single flange face in real time in the form of radar charts and bar charts; and to track the axial force change trend of a single bolt under the conditions of gusts of wind, rotation speed and power increase in the form of line charts.

8. The online measurement and control system for bolt preload of a wind turbine as described in claim 1, characterized in that, The software functions within the bolt monitoring host include: measuring bolt preload, calculating and tracking bolt load, trend tracking and early warning; the bolt monitoring host is used to record and store channel number, waveform, echo time, sound time difference, elongation, preload, ambient temperature and measurement time.

9. A method for online measurement and control of bolt preload in wind turbine units, characterized in that, include: S1: Control the ultrasonic probe to emit ultrasonic pulses into the bolt being tested, and receive the echo signal reflected from the end face of the bolt being tested, while simultaneously collecting the ambient temperature data of the bolt being tested. S2: Control the bolt monitoring host to collect echo signals, and perform analog-to-digital conversion and echo time difference data measurement on the echo signals; S3: Control the communication link to transmit the output of each bolt monitoring host to the monitoring server; S4: The control and monitoring server performs temperature compensation calculations on the received echo time difference data and ambient temperature data to obtain the bolt preload value; S5: The control and monitoring server performs trend analysis and threshold alarms on bolt preload values. The online monitoring platform software presents the axial force distribution of all uniformly distributed bolts in a single flange face in real time in the form of radar charts and bar charts, and tracks the axial force change trend of a single bolt under the conditions of gusts of wind, speed and power increase in line chart.

10. The method for online measurement and control of bolt preload in a wind turbine generator according to claim 9, characterized in that, S4 specifically includes: based on Calculate the bolt preload value of the bolt being tested; In the formula, F is the bolt preload, E is the elastic modulus of the bolt being tested, S is the cross-sectional area of ​​the bolt being tested, L is the clamping length of the bolt being tested, and ΔL is the deformation of the bolt being tested.

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