On-line monitoring system and monitoring method for weld joint of fan tower barrel

Abstract

The invention relates to the technical field of fan monitoring, and discloses a fan tower tube weld joint online monitoring system and a monitoring method thereof.The monitoring system comprises a tilt angle sensor installed on a tower tube and used for measuring the tilt angle of the tower tube, a vibration acceleration sensor used for measuring the vibration acceleration of the tower tube and a controller installed on the upper side and the lower side of the weld joint, the strain sensor is used for measuring strain changes of corresponding positions, the temperature sensor is used for measuring temperature changes of the corresponding positions, the data collector is arranged at the bottom of the tower drum and used for collecting measurement data of the tilt angle sensor, the vibration acceleration sensor, the strain sensor and the temperature sensor, and the remote operation monitoring station is arranged in the tower drum. The far-end monitoring device is used for analyzing the change condition of the tower drum after acquiring the corresponding data acquired by the data acquisition unit; according to the invention, real-time monitoring and early warning of tower drum inclination, tower drum overload and foundation differential settlement faults are realized, and the method has the advantages of comprehensive monitoring and safe and stable operation of a unit.

Description

Technical Field

[0001] The invention relates to an online monitoring system for a fan tower weld and a monitoring method thereof, belonging to the technical field of fan monitoring. Background Art

[0002] A wind turbine, commonly referred to as a wind turbine, is a device that converts wind energy into electricity and plays a vital role in the renewable energy sector. After long-term operation, wind turbine components can wear and corrode, leading to decreased performance and increased failure rates. Replacement is necessary to maintain power generation efficiency and stability. A common replacement involves replacing only the wind turbine, without replacing the foundation, current collection lines, and other components. However, after the replacement, the new wind turbine may differ from the original in weight, tower height, and impeller diameter. This significantly changes the load on the new turbine during operation when installed on the foundation. This can lead to potential failures such as uneven tower settlement, tower tilt, unit resonance, and tower overload. Furthermore, during the replacement process, the tower and connecting flanges must be re-welded. This structural strength may differ from the original unit, potentially leading to weld cracking and tower wall cracking.

[0003] To this end, in the prior art, there is an invention patent application with Chinese patent application number CN202110193182.9, which discloses a system and method for monitoring the subtle settlement and tilt of a wind turbine tower. The system uses a laser transmitter to conduct online monitoring of the safety and health status of the tower, specifically detecting the settlement and tilt of the tower, so as to achieve real-time monitoring and early warning of wind turbine tower failures and ensure the safe and stable operation of the wind turbine unit. However, it still lacks monitoring of the tower load and natural frequency during use. At the same time, the online monitoring of the laser transmitter may also suffer from laser fading, which may affect its monitoring results of the tower settlement and tilt, resulting in inaccurate results. Summary of the Invention

[0004] In order to solve the above problems existing in the prior art, the present invention provides a wind turbine tower weld online monitoring system and a monitoring method thereof.

[0005] The technical solutions of the present invention are as follows: In the first aspect, the present invention provides an online monitoring system for the weld of a wind turbine tower, comprising an inclination sensor installed on the tower for measuring the inclination angle of the tower, a vibration acceleration sensor installed on the tower for measuring the vibration acceleration of the tower, strain sensors installed at the upper and lower sides of the weld for measuring the strain changes at corresponding positions, a temperature sensor installed at the upper and lower sides of the weld for measuring the temperature changes at corresponding positions, a data collector arranged at the bottom of the tower, which is electrically connected to the inclination sensor, the vibration acceleration sensor, the strain sensor and the temperature sensor to collect measurement data of the inclination sensor, the vibration acceleration sensor, the strain sensor and the temperature sensor, and a remote monitoring device arranged in a remote operation monitoring station, which is communicatively connected to the data collector by setting a communication module to acquire the corresponding data collected by the data collector and then analyze the changes in the tower.

[0006] Furthermore, the remote monitoring device obtains data measured by the inclination sensor and the vibration acceleration sensor to generate a dynamic stiffness circle monitoring map and a tower natural frequency monitoring map, and the remote monitoring device obtains data measured by the strain sensor and the temperature sensor to generate a tower load monitoring map, so as to analyze the changes in the tower.

[0007] Furthermore, the remote monitoring device is preset with a stiffness warning value, a natural frequency warning value and a load warning value. The remote monitoring device monitors the tower stiffness through a dynamic stiffness circle monitoring map, monitors the tower natural frequency through a tower natural frequency monitoring map and monitors the tower load through a tower load monitoring map, and sends an alarm signal when the tower stiffness exceeds the stiffness warning value, the tower natural frequency exceeds the natural frequency warning value and the tower load exceeds the load warning value.

[0008] Furthermore, the number of the inclination sensors and the vibration acceleration sensors are both two, and one inclination sensor and one vibration acceleration sensor are both provided at the lower part of the yaw flange of the tower and the lower part of the upper flange of the base ring.

[0009] Furthermore, the strain sensors and temperature sensors form multiple monitoring groups, each monitoring group includes three strain sensors and two temperature sensors. The multiple monitoring groups are arranged at different horizontal heights at the upper and lower sides of the weld. The three strain sensors in each monitoring group are distributed in a circular array with the center line of the tower as the array center at the corresponding positions, and the two temperature sensors and the three strain sensors are staggered.

[0010] Furthermore, the strain sensors located on both sides of the monitoring group are installed parallel to the ground, and the strain sensor located in the middle is installed perpendicular to the ground.

[0011] Furthermore, the number of the monitoring groups is four, and the distribution of the monitoring groups at the upper and lower sides of the weld is: 0.1m above the weld, 0.2m above the weld, 0.1m below the weld, and 0.2m below the weld.

[0012] In a second aspect, the present invention provides a monitoring method for the aforementioned wind turbine tower weld online monitoring system, comprising the following steps: Step 1: Install the tilt sensor and vibration acceleration sensor on the tower, install the strain sensor and temperature sensor on the upper and lower sides of the weld, install the data collector in the tower control cabinet at the bottom of the tower, electrically connect the data collector to the tilt sensor, vibration acceleration sensor, strain sensor and temperature sensor, and connect the data collector to the remote monitoring device through the communication module; Step 2: Carry out monitoring work; the remote monitoring device obtains the corresponding data collected by the data collector through the communication module, monitors and analyzes the changes in the tower in real time after calculation, and feeds back to the operating personnel.

[0013] Furthermore, the method for the remote monitoring device to analyze tower changes in the aforementioned second step includes the following steps: the remote monitoring device generates a dynamic stiffness circle monitoring map and a tower natural frequency monitoring map by acquiring data measured by the inclination sensor and the vibration acceleration sensor; the remote monitoring device also generates a tower load monitoring map by acquiring data measured by the strain sensor and the temperature sensor, thereby analyzing the changes in the tower.

[0014] Furthermore, the method for the remote monitoring device to analyze tower changes in the aforementioned second step includes the following steps: presetting a stiffness warning value, a natural frequency warning value, and a load warning value in the remote monitoring device, the remote monitoring device monitors the tower stiffness through a generated dynamic stiffness circle monitoring map, monitors the tower natural frequency through a generated tower natural frequency monitoring map, and monitors the tower load through a generated tower load monitoring map, and sends an alarm signal to remind the operating personnel when the tower stiffness exceeds the stiffness warning value, the tower natural frequency exceeds the natural frequency warning value, and the tower load exceeds the load warning value.

[0015] The present invention has the following beneficial effects: The present invention provides structures such as an inclination sensor, a vibration acceleration sensor, a strain sensor, and a temperature sensor. By installing the inclination sensor and the vibration accelerator sensor on the tower, the inclination angle of the tower and the vibration acceleration of the tower can be measured in real time, thereby monitoring the inclination posture and natural frequency of the tower. By installing the strain sensor and the temperature sensor on the upper and lower sides of the weld, the load on this part of the tower can be measured in real time. In conjunction with the provided data collector and the remote monitoring device, the data collector collects the data measured by the above sensors and sends it to the remote monitoring device through a communication module for the remote monitoring device to analyze the changes in the tower and make corresponding early warnings. Compared with the existing technology, the present invention realizes real-time monitoring and early warning of tower tilt, tower overload, and uneven foundation settlement faults, and has the advantages of comprehensive monitoring and ensuring safe and stable operation of the unit. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the module composition of the wind turbine tower weld online monitoring system of the present invention; Figure 2 Schematic diagram of the distribution of strain sensors and temperature sensors in the monitoring group of the present invention.

[0017] The reference numerals in the figures are as follows: 1. Inclination sensor; 2. Vibration acceleration sensor; 3. Strain sensor; 4. Temperature sensor; 5. Data collector; 6. Communication module; 7. Remote monitoring device. DETAILED DESCRIPTION

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0019] It should be understood that the step numbers used herein are only for convenience of description and are not intended to limit the order in which the steps are to be executed.

[0020] It should be understood that the terms used in the present specification are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in the present specification and the appended claims, the singular forms "a", "an" and "the" are intended to include the plural forms unless the context clearly indicates otherwise.

[0021] The terms “include” and “comprising” indicate the presence of described features, integers, steps, operations, elements and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof.

[0022] The term "and / or" refers to and includes any and all possible combinations of one or more of the associated listed items.

[0023] Example: Please refer to Figure 1 and Figure 2 This embodiment provides an online monitoring system for a wind turbine tower weld and a monitoring method thereof. In this embodiment, the online monitoring system for a wind turbine tower weld includes an inclination sensor 1, a vibration acceleration sensor 2, a strain sensor 3, a temperature sensor 4, a data collector 5, and a remote monitoring device 7. The inclination sensor 1 is selected as a composite biaxial dynamic inclination sensor 1, and the vibration acceleration sensor is selected as a biaxial vibration acceleration sensor 2. The inclination sensor 1 and the vibration acceleration sensor 2 are both installed on the tower, and are used to measure the inclination angle of the tower and the vibration acceleration of the tower, respectively. The strain sensor 3 is selected as an optical fiber strain sensor 3, and the temperature sensor 4 is selected as an optical fiber temperature sensor 4. The strain sensor 3 and the temperature sensor 4 are both installed at the upper and lower sides of the weld, and are used to measure the strain change and the temperature change at the corresponding position, respectively. The data collector 5 is located at the bottom of the tower, specifically within the tower control cabinet. The data collector 5 is electrically connected to the inclination sensor 1, the vibration acceleration sensor 2, the strain sensor 3, and the temperature sensor 4, thereby enabling the collection of data measured by the inclination sensor 1, the vibration acceleration sensor 2, the strain sensor 3, and the temperature sensor 4. A remote monitoring device 7 is located within the remote operation monitoring station. This device communicates with the data collector 5 via a communication module 6, enabling the acquisition of the corresponding data collected by the data collector 5 and analysis of tower changes, thereby enabling real-time monitoring of the tower.

[0024] In this embodiment, the remote monitoring device 7 performs real-time monitoring of the tower in the following manner: the remote monitoring device 7 generates a dynamic stiffness circle monitoring map and a tower natural frequency monitoring map by acquiring data measured by the inclination sensor 1 and the vibration acceleration sensor 2. The remote monitoring device 7 also generates a tower load monitoring map by acquiring data measured by the strain sensor 3 and the temperature sensor 4, thereby analyzing changes in the tower and achieving real-time monitoring.

[0025] In this embodiment, the remote monitoring device 7 generates the dynamic stiffness circle monitoring map in the following manner: The coordinate matrix T is constructed according to the tower inclination angle and azimuth angle. The coordinate transformation matrix is:

[0026] Wherein, T represents the coordinate transformation matrix, θ represents the tower tilt angle, and φ represents the tower azimuth. The tower tilt angle and azimuth are both directly measured by the tilt sensor 1.

[0027] Afterwards, the coordinate transformation matrix T is modified to obtain the following stiffness matrix:

[0028] Where K represents the stiffness matrix, T T represents the transposed matrix of the coordinate transformation matrix, and K0 represents the stiffness matrix of the tower, which is directly obtained from the actual material properties and specific geometric dimensions of the tower through finite element analysis or theoretical derivation.

[0029] Then, the dynamic stiffness K is calculated according to the stiffness matrix K using the following formula: * :

[0030] Wherein, m represents the mass of the tower, which is determined according to the actual weight of the tower, ω represents the angular frequency, which is directly measured by the vibration acceleration sensor 2, i represents the imaginary unit, and c represents the damping coefficient of the tower, which is determined according to the actual material properties of the tower.

[0031] Finally, according to the dynamic stiffness K * Draw the dynamic stiffness circle on the complex plane as follows: K * It can be expressed in the complex plane as:

[0032] Where K real represents K-mω 2 is the real part, K imag Indicates that cω is the imaginary part, and the angular frequency ω measured by the vibration acceleration sensor 2 in real time is constantly changing, that is, a series of K real , K imag points, which constitute the required dynamic stiffness circle on the complex plane.

[0033] Then, a dynamic stiffness circle monitoring map can be generated based on the drawn dynamic stiffness circle.

[0034] The remote monitoring device 7 generates the tower natural frequency monitoring spectrum in the following manner: The tower natural frequency is calculated using the following formula:

[0035] Where, f n represents the natural frequency of the tower, K represents the stiffness matrix, and m represents the mass of the tower.

[0036] Then, a tower natural frequency monitoring spectrum can be generated based on the calculated tower natural frequency.

[0037] The remote monitoring device 7 generates the tower load monitoring map in the following manner: Since temperature changes will cause deformation of the strain sensor 3, thus affecting the accuracy of stress measurement, the temperature sensor 4 is installed to compensate by measuring the temperature. The specific compensation method is: Assume that the total strain ε measured by the strain sensor 3 includes the strain ε1 caused by stress and the strain ε2 caused by temperature change.

[0038] The strain caused by temperature change is calculated using the following formula:

[0039] Wherein, α represents the thermal expansion coefficient of the tower material, which is determined by the actual material properties of the tower; ΔT represents the temperature change measured by the temperature sensor 4, which is obtained by subtracting the temperature measured by the temperature sensor 4 from the preset initial temperature. The preset initial temperature is set according to the actual situation.

[0040] Then, the strain ε1 caused by the actual stress can be obtained by subtracting the strain ε2 caused by temperature change from the total strain ε.

[0041] The tower stress is then calculated using the following formula:

[0042] Where σ represents the tower stress and E represents the elastic modulus of the tower, which is determined according to the actual material properties of the tower.

[0043] Then, the corresponding tower load monitoring map can be generated based on the calculated tower stress.

[0044] In this embodiment, the remote monitoring device 7 also has preset stiffness warning values, natural frequency warning values, and load warning values. The specific values ​​of the stiffness warning values, natural frequency warning values, and load warning values ​​are selected and set according to actual conditions. The remote monitoring device 7 monitors tower stiffness using a dynamic stiffness circle monitoring graph, tower natural frequency using a tower natural frequency monitoring graph, and tower load using a tower load monitoring graph. It issues an alarm signal when the tower stiffness exceeds the stiffness warning value, the tower natural frequency exceeds the natural frequency warning value, or the tower load exceeds the load warning value.

[0045] In this embodiment, there are two inclination sensors 1 and two vibration acceleration sensors, and one inclination sensor 1 and one vibration acceleration sensor are respectively provided at the lower part of the yaw flange of the tower and the lower part of the upper flange of the base ring.

[0046] In this embodiment, strain sensors 3 and temperature sensors 4 form multiple monitoring groups, specifically four in number, which can be adjusted based on actual conditions. Each monitoring group contains three strain sensors 3 and two temperature sensors 4. The multiple monitoring groups are positioned at different heights above and below the weld. Specifically, the four monitoring groups are positioned 0.1 m above the weld, 0.2 m above the weld, 0.1 m below the weld, and 0.2 m below the weld. The three strain sensors 3 in each monitoring group are arranged in a circular array centered on the centerline of the tower. The two temperature sensors 4 are staggered with the three strain sensors 3. Furthermore, the strain sensors 3 on the sides of each monitoring group are mounted parallel to the ground for torque testing, while the strain sensor 3 in the middle is mounted perpendicular to the ground for bending moment testing. The two temperature sensors 4 in the same monitoring group provide temperature compensation data for these three strain sensors 3.

[0047] In this embodiment, the monitoring method corresponding to the wind turbine tower weld online monitoring system includes the following steps: Step 1: Install the inclination sensor 1 and the vibration acceleration sensor 2 on the tower. The specific installation method is: Prepare two inclination sensors 1 and two vibration acceleration sensors 2, and then set the tower top measuring point and the tower bottom measuring point. The tower top measuring point is the lower part of the yaw flange, which can be specifically about 1m in the north direction, and the tower bottom measuring point is the lower part of the upper flange of the foundation ring, which can be specifically about 0.4m in the north direction. Then, the sensor mounting bracket is solidified and combined with the two measuring point positions through steel glue, and after horizontal calibration with a spirit level, the inclination sensor 1 and the vibration acceleration sensor 2 are installed on the sensor mounting bracket, and the sensors are fixed with hexagonal screws so that one inclination sensor 1 and one vibration acceleration sensor 2 are set at the tower top measuring point and the tower bottom measuring point.

[0048] Install the strain sensor 3 and temperature sensor 4 at the upper and lower sides of the weld. The specific installation method is: Prepare a total of twelve strain sensors 3 and eight temperature sensors 4. Group three strain sensors 3 and two temperature sensors 4 into a group, totaling four groups, forming four monitoring groups. Then select four installation locations, namely: 0.1m above the weld, 0.2m above the weld, 0.1m below the weld, and 0.2m below the weld. Then install a monitoring group at each installation location. The distribution of the monitoring group at the installation location is as follows: the three strain sensors 3 in the monitoring group are distributed in a circular array with the center line of the tower as the array center at the corresponding position. The specific positions of the three strain sensors 3 are at 0°, 90°, and 180° within the installation circular section. Among them, the strain sensors 3 at the 0° and 180° positions are installed parallel to the ground for torque testing, and the strain sensor 3 at the 90° position is installed perpendicular to the ground for bending moment testing. The two temperature sensors 4 and the three strain sensors 3 are staggered. The specific positions of the two temperature sensors 4 are at 45° and 135° within the installation circular section, so as to provide temperature compensation data for the three strain sensors 3 well.

[0049] The data collector 5 is installed in the tower control cabinet at the bottom of the tower, and then the data collector 5 is electrically connected to all the inclination sensors 1, vibration acceleration sensors, strain sensors 3 and temperature sensors 4 so that the data collector 5 can collect the data measured by all the inclination sensors 1, vibration acceleration sensors, strain sensors 3 and temperature sensors 4.

[0050] The data collector 5 is communicatively connected to the remote monitoring device 7 via the communication module 6 , so that the remote monitoring device 7 can obtain the data collected by the data collector 5 .

[0051] Step 2: Perform monitoring. The remote monitoring device 7 obtains the corresponding data collected by the data collector 5 through the communication module 6, monitors and analyzes the changes in the tower in real time after calculation, and provides feedback to the operator. The method for the remote monitoring device 7 to analyze the changes in the tower includes the following steps: presetting a corresponding program on the remote monitoring device 7, which is shown in the various map generation methods of the wind turbine tower weld online monitoring system described above. This allows the remote monitoring device 7 to generate dynamic stiffness circle monitoring maps and tower natural frequency monitoring maps by obtaining data measured by the inclination sensor 1 and the vibration acceleration sensor 2, and to generate tower load monitoring maps by obtaining data measured by the strain sensor 3 and the temperature sensor 4, thereby analyzing the changes in the tower and achieving real-time monitoring. At the same time, the stiffness warning value, natural frequency warning value and load warning value are preset in the remote monitoring device 7. The stiffness warning value, natural frequency warning value and load warning value can be selected and set according to actual conditions, so that the remote monitoring device 7 monitors the tower stiffness through the generated dynamic stiffness circle monitoring map, monitors the tower natural frequency through the generated tower natural frequency monitoring map and monitors the tower load through the generated tower load monitoring map, and sends an alarm signal to remind the operating personnel that a fault has occurred when the tower stiffness exceeds the stiffness warning value, the tower natural frequency exceeds the natural frequency warning value and the tower load exceeds the load warning value, so as to ensure the safe and stable operation of the unit.

[0052] Those skilled in the art will appreciate that the various units and algorithm steps described in the embodiments disclosed herein can be implemented using a combination of electronic hardware, computer software, and electronic hardware. Whether these functions are performed in hardware or software depends on the specific application and design constraints of the technical solution. Professionals and technicians can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of this application.

[0053] Those skilled in the art will clearly understand that, for the convenience and brevity of description, the specific working processes of the systems, devices and units described above can refer to the corresponding processes in the aforementioned method embodiments and will not be repeated here.

[0054] The above descriptions are merely embodiments of the present invention and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention's description and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A wind turbine tower weld online monitoring system, characterized by: include An inclination sensor (1) is installed on the tower and is used to measure the inclination angle of the tower; A vibration acceleration sensor (2) is installed on the tower and is used to measure the vibration acceleration of the tower; Strain sensors (3); installed at the upper and lower sides of the weld, for measuring strain changes at corresponding positions; Temperature sensors (4); installed at the upper and lower sides of the weld, for measuring temperature changes at corresponding locations; A data collector (5) is provided at the bottom of the tower and is used to collect measurement data from the inclination sensor (1), the vibration acceleration sensor (2), the strain sensor (3) and the temperature sensor (4); A remote monitoring device (7) is provided in a remote operation monitoring station, and acquires corresponding data collected by the data collector (5) by providing a communication module (6) and analyzes changes in the tower.

2. The wind turbine tower weld online monitoring system according to claim 1, characterized in that: The remote monitoring device (7) obtains data measured by the tilt sensor (1) and the vibration acceleration sensor (2) to generate a dynamic stiffness circle monitoring spectrum and a tower natural frequency monitoring spectrum. The remote monitoring device (7) obtains data measured by the strain sensor (3) and the temperature sensor (4) to generate a tower load monitoring spectrum, thereby analyzing changes in the tower.

3. The wind turbine tower weld online monitoring system according to claim 2, characterized in that: The remote monitoring device (7) is preset with a stiffness warning value, a natural frequency warning value, and a load warning value. The remote monitoring device (7) monitors the tower stiffness through a dynamic stiffness circle monitoring spectrum, monitors the tower natural frequency through a tower natural frequency monitoring spectrum, and monitors the tower load through a tower load monitoring spectrum, and issues an alarm signal when the tower stiffness exceeds the stiffness warning value, the tower natural frequency exceeds the natural frequency warning value, and the tower load exceeds the load warning value.

4. The wind turbine tower weld online monitoring system according to claim 1, characterized in that: The number of the inclination sensors (1) and the number of the vibration acceleration sensors are both two, and one inclination sensor (1) and one vibration acceleration sensor are both provided at the lower part of the yaw flange of the tower and the lower part of the upper flange of the foundation ring.

5. The wind turbine tower weld online monitoring system according to claim 1, characterized in that: The strain sensors (3) and temperature sensors (4) form a plurality of monitoring groups, each monitoring group comprising three strain sensors (3) and two temperature sensors (4), the plurality of monitoring groups being arranged at different levels at the upper and lower sides of the weld, the three strain sensors (3) in each monitoring group being distributed at corresponding positions in a circular array with the center line of the tower as the array center, and the two temperature sensors (4) and the three strain sensors (3) being arranged in an interlaced manner.

6. The wind turbine tower weld online monitoring system according to claim 5, characterized in that: The strain sensors (3) located on both sides of the monitoring group are installed parallel to the ground, and the strain sensor (3) located in the middle is installed perpendicular to the ground.

7. The wind turbine tower weld online monitoring system according to claim 5, characterized in that: There are four monitoring groups, and the monitoring groups are distributed at the upper and lower sides of the weld as follows: 0.1m above the weld, 0.2m above the weld, 0.1m below the weld, and 0.2m below the weld.

8. A monitoring method for a wind turbine tower weld online monitoring system according to any one of claims 1 to 7, characterized in that: The following steps are involved: Step A1: Perform installation work; The tilt sensor (1) and the vibration acceleration sensor (2) are installed on the tower, the strain sensor (3) and the temperature sensor (4) are installed at the upper and lower sides of the weld, the data collector (5) is installed in the tower control cabinet at the bottom of the tower, the data collector (5) is electrically connected to the tilt sensor (1), the vibration acceleration sensor, the strain sensor (3) and the temperature sensor (4), and the data collector (5) is communicatively connected to the remote monitoring device (7) through the communication module (6); Step A2: Perform monitoring work; the remote monitoring device (7) obtains the corresponding data collected by the data collector (5) through the communication module (6), monitors and analyzes the changes in the tower in real time after calculation, and feeds back to the operator.

9. A monitoring method for a wind turbine tower weld online monitoring system according to claim 8, characterized in that: The method for analyzing the tower change by the remote monitoring device (7) in step A2 includes the following steps: the remote monitoring device (7) generates a dynamic stiffness circle monitoring spectrum and a tower natural frequency monitoring spectrum by acquiring data measured by the tilt sensor (1) and the vibration acceleration sensor (2); the remote monitoring device (7) also generates a tower load monitoring spectrum by acquiring data measured by the strain sensor (3) and the temperature sensor (4), thereby analyzing the tower change.

10. A monitoring method for a wind turbine tower weld online monitoring system according to claim 9, characterized in that: The method for analyzing the tower change by the remote monitoring device (7) in step A2 further includes the following steps: presetting a stiffness warning value, a natural frequency warning value, and a load warning value in the remote monitoring device (7), the remote monitoring device (7) monitoring the tower stiffness through a generated dynamic stiffness circle monitoring map, monitoring the tower natural frequency through a generated tower natural frequency monitoring map, and monitoring the tower load through a generated tower load monitoring map, and sending an alarm signal to remind the operator when the tower stiffness exceeds the stiffness warning value, the tower natural frequency exceeds the natural frequency warning value, and the tower load exceeds the load warning value.

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