Abnormal monitoring method of cable force in mixed tower based on high-precision displacement sensor

Abstract

The invention relates to the technical field of wind turbine hybrid tower health status monitoring, and specifically to a hybrid tower cable force anomaly monitoring method based on a high-precision displacement sensor. The high-precision displacement sensor is arranged at the transverse seam of a hybrid tower C-type component to measure the size of the transverse seam gap of the hybrid tower C-type component in real time; the wind turbine unit operating data, including the yaw angle and the wind speed or the rotation speed, are collected; the high-precision displacement sensor data within the yaw angle within ±30 degrees is obtained, a correlation curve between the transverse seam gap of the C-type component and the wind speed or the rotation speed under the yaw angle range is established, and a transverse seam gap threshold range of the C-type component under different wind speeds or rotation speeds is established; when the transverse seam gap of the C-type component exceeds the transverse seam gap threshold range of the C-type component, an abnormal C-type component gap warning is issued, thereby achieving the purpose of hybrid tower cable force anomaly monitoring, and the cost is low, the sensor is convenient to install, and the application range is wide.

Description

Technical Field

[0001] The invention relates to the technical field of wind turbine generator set hybrid tower health status monitoring, and in particular to a hybrid tower cable force anomaly monitoring method based on a high-precision displacement sensor. Background Art

[0002] With the development of large-scale wind turbines with high power, long blades and high towers, hybrid towers have become a more economical and safer choice. The upper part of the hybrid tower is composed of steel sections and the lower part is concrete sections. Due to the characteristics of concrete materials: high rigidity and weak tensile strength, in order to improve the safety of the tower, prestressing will be carried out after the concrete sections are spliced. The use of prestressed concrete towers can improve the bearing capacity, stability and durability of wind turbine towers, while reducing construction and maintenance costs. Monitoring the cable force of prestressed cables is one of the important measures to ensure the safety and effective operation of wind turbine tower structures. The cable force of prestressed cables directly affects the stability and bearing capacity of the tower structure. By monitoring the cable force, problems such as looseness, corrosion or fatigue in the prestressed cables can be discovered in time, and preventive maintenance measures can be taken in time to avoid collapse or damage to the tower structure due to failure of prestressed cables, thereby ensuring the safety of personnel and equipment.

[0003] At present, the commonly used methods for measuring anchor cable force include vibrating string measurement method, vibration fundamental frequency measurement method, anchor cable pressure gasket method, etc. The vibrating string measurement method is to install a vibrating string anchor cable strain gauge on the anchor cable to measure the stress change of the anchor cable during the operation of the mixed tower. This method has low accuracy. The vibration fundamental frequency measurement method is to install an acceleration sensor on the anchor cable, extract the fundamental frequency through spectrum analysis to calculate the cable force. This method is the most widely used, but the cost is high, and it cannot be used for internal anchor cable mixed towers. The anchor cable pressure measurement method is to deploy a pressure sensor gasket before installing the mixed tower anchor cable, which can directly and effectively measure the tension of the mixed tower anchor cable, but this method needs to be deployed in advance, cannot be deployed for units that are already in operation, and later maintenance is more difficult. Summary of the invention

[0004] The present invention provides a method for monitoring abnormal cable tension in a mixed tower based on a high-precision displacement sensor. By measuring the transverse seam gap of the C-type component, a correlation curve between the transverse seam gap of the C-type component within a yaw angle of ±30 degrees and the wind speed or rotation speed is established, and a relative abnormal warning of the anchor cable force can be achieved. The method has low cost, convenient sensor installation and a wide range of applications.

[0005] In order to solve the above technical problems, the technical solution of the present invention is:

[0006] The present invention provides a method for monitoring abnormal cable tension of a hybrid tower based on a high-precision displacement sensor, comprising the following steps:

[0007] S1. The C-type components of the mixing tower are firmly connected by applying tension pre-tightening force through the anchor cables connected up and down. High-precision displacement sensors are arranged at the transverse joints of the C-type components of the mixing tower to measure the size of the transverse joints of the C-type components of the mixing tower in real time;

[0008] S2. Collect wind turbine unit operating data, including yaw angle and wind speed or rotation speed;

[0009] S3. Acquire high-precision displacement sensor data within a yaw angle of ±30 degrees, establish a correlation curve between the transverse seam gap of the C-type component and the wind speed or rotation speed within the yaw angle range, and establish a transverse seam gap threshold range of the C-type component under different wind speeds or rotation speeds. When the transverse seam gap of the C-type component exceeds the transverse seam gap threshold range of the C-type component, issue a transverse seam gap abnormality warning for the C-type component, i.e., a relative cable force abnormality warning.

[0010] For the mixed tower with external anchor cables, in step S1, a fundamental frequency cable force sensor is also installed on the external segment of the lower anchor head of the anchor cable at the bottom of the mixed tower to monitor and calculate the real-time cable force value of the anchor cable, that is, the anchor cable tension; according to the real-time measurement value of the anchor cable tension and the transverse seam gap of the C-type component within the yaw angle of ±30 degrees, the relative coefficient between the anchor cable tension and the transverse seam gap of the C-type component is fitted and calibrated to obtain the relative relationship between the anchor cable tension and the transverse seam gap of the C-type component, thereby realizing the reverse calculation of the physical actual value of the anchor cable tension according to the real-time measurement value of the transverse seam gap of the C-type component of the mixed tower on the same model unit.

[0011] Within the range of yaw angle of ±30 degrees, a correlation curve is established between the actual physical value of the anchor cable tension calculated by monitoring the transverse seam gap of the C-type component and the wind speed or rotation speed, and a threshold range of the anchor cable tension under different wind speeds or rotation speeds is established. When the actual physical value of the anchor cable tension is lower than the threshold range of the anchor cable tension, an abnormal hybrid tower cable tension warning is issued.

[0012] The fundamental frequency cable force sensor is an acceleration sensor.

[0013] The high-precision displacement sensor is a micron-level displacement sensor.

[0014] In step S1, more than four high-precision displacement sensors are arranged at each transverse seam of the C-type component and are evenly distributed along the circumference of the mixing tower.

[0015] In step S3, the yaw angle range is selected within ±15 degrees.

[0016] Compared with the prior art, the present invention has the following beneficial effects: (1) By measuring the transverse gap of the C-type component, the present invention establishes a correlation curve between the transverse gap of the C-type component within a yaw angle of ±30 degrees and the wind speed or rotation speed, and realizes a relative abnormal warning of the anchor cable force.

[0017] (2) Based on gap monitoring and combined with the fundamental frequency cable force monitoring of the external anchor cable, the present invention fits and calibrates the relative coefficient of the anchor cable tension and the transverse gap of the C-type component, and establishes the relative relationship between the anchor cable tension and the transverse gap of the C-type component, thereby realizing the reverse calculation of the physical actual value of the anchor cable tension based on the measured transverse gap of the C-type component on the same model unit; and establishes a correlation curve between the physical actual value of the anchor cable tension within a yaw angle of ±30 degrees and the wind speed or rotation speed, so as to provide an early warning for abnormal anchor cable tension. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a simplified schematic diagram of the structure of the mixed tower anchor cable and C-type component;

[0019] Figure 2 A correlation curve diagram between the transverse gap of the C-type component and the wind speed or rotation speed established in the present invention;

[0020] Figure 3 It is a schematic diagram of the arrangement of the high-precision displacement sensor and the fundamental frequency cable force sensor on the mixing tower of the external anchor cable in the present invention;

[0021] Figure 4 A correlation curve diagram between the actual physical value of the anchor cable tension and the wind speed or rotation speed established in the present invention;

[0022] In the figure, 1-C type component, 2-anchor cable, 3-high precision displacement sensor, 4-fundamental frequency cable force sensor. DETAILED DESCRIPTION

[0023] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0024] The mixed tower is formed by splicing C-type components 1. Each C-type component 1 is firmly connected by applying a tension pre-tightening force through the anchor cables 2 connected up and down. The simplified schematic diagram of the structure of the mixed tower anchor cables 2 and C-type components 1 is shown in Figure 1 As shown. There will be a tiny gap at the transverse connection between C-type component 1 and C-type component 1, that is, the transverse gap δ of the C-type component. F in the figure is the anchor cable tension. When the wind turbine is running, the mixed tower will cause the anchor cable tension to fluctuate under the action of external loads. Therefore, during the operation of the wind turbine, the transverse gap δ of the C-type component will fluctuate within a certain range. When the anchor cable 2 has problems such as looseness, corrosion or fatigue, the anchor cable tension F will decrease (that is, the mixed tower cable force will decay), which will reduce the pressure between the two surfaces of the C-type component. Then the transverse gap δ of the C-type component caused by the external load will fluctuate more. Therefore, by monitoring the size of the transverse gap δ of the C-type component, the change of the anchor cable tension F of the mixed tower can be effectively monitored.

[0025] pass Figure 1 From the simplified schematic diagram in , it can be assumed that the relationship between the transverse gap δ of the C-type component and the anchor cable tension F is as follows:

[0026] ;

[0027] in The load change on the contact surface of the C-type component caused by the external load during the operation of the fan;

[0028] K is the relative coefficient of the anchor cable tension F and the transverse gap δ of the C-type component;

[0029] n is the order of the relationship between the anchor tension F and the transverse gap δ of the C-type component, which may be 1, 2, …, n;

[0030] Therefore, when When the anchor cable tension F and the C-type component transverse seam gap δ are the same, it can be considered that there is a linear or nonlinear relationship between them. Therefore, when monitoring and early warning, the different rotation speeds or wind speeds can be used to divide the compartments, and the displacement relationship between the anchor cable tension F, the C-type component transverse seam gap δ and the wind speed or rotation speed can be established, so as to provide an early warning of cable force attenuation.

[0031] Based on the above principle, the present invention provides a method for monitoring abnormal cable tension of a hybrid tower based on a high-precision displacement sensor, comprising the following steps:

[0032] S1. Arrange a high-precision displacement sensor 3 at the transverse seam of the C-type component 1 of the mixing tower to measure the size of the transverse seam gap δ of the C-type component of the mixing tower in real time; preferably, the high-precision displacement sensor 3 is a micron-level displacement sensor; preferably, more than four high-precision displacement sensors 3 are arranged at the transverse seam of each C-type component 1, and are evenly distributed along the circumference of the mixing tower.

[0033] S2. Collect wind turbine unit operating data, including yaw angle and wind speed or rotation speed;

[0034] S3, obtain the data of high-precision displacement sensor 3 within the yaw angle of ±30 degrees (i.e., yaw angle ≤30°), and establish the correlation curve between the transverse gap δ of the C-type component and the wind speed or rotation speed under the yaw angle range, such as Figure 2 As shown, a threshold range of transverse seam gap of C-type components under different wind speeds or rotation speeds is established, that is, the upper warning line in the figure. The transverse seam gap δ of the C-type component under the same wind speed or rotation speed is compared with the transverse seam gap threshold of the C-type component. When the transverse seam gap δ of the C-type component exceeds the transverse seam gap threshold range of the C-type component (that is, when it exceeds the range of the upper warning line), an abnormal transverse seam gap warning of the C-type component is issued, that is, an abnormal relative cable force warning. Preferably, the yaw angle range is selected within ±15 degrees, that is, high-precision displacement sensor data with a yaw angle range within ±15 degrees is selected to establish a correlation curve between the transverse seam gap δ of the C-type component and the wind speed or rotation speed.

[0035] The anchor cable 2 of the mixed tower is generally divided into an external anchor cable and an internal anchor cable. In this embodiment, for the mixed tower with external anchor cables, the relative coefficient K of the anchor cable tension F and the transverse gap δ of the C-type component is fitted and calibrated, so as to obtain the relative relationship between the anchor cable tension F and the transverse gap δ of the C-type component, so as to realize that only the transverse gap δ of the C-type component is monitored on the same type of unit, and the anchor cable tension F can be obtained by reverse calculation. Specifically, in step S1 of the above method, a high-precision displacement sensor 3 and a fundamental frequency cable force sensor 4 are arranged at the same time, such as Figure 3 As shown, a fundamental frequency cable force sensor 4 is installed on the outer segment of the lower anchor head of the anchor cable 2 at the bottom of the mixed tower to monitor and calculate the real-time cable force value of the anchor cable, that is, the anchor cable tension F; specifically, a fundamental frequency cable force sensor 4 is installed on the outer segment of the lower anchor head of the anchor cable 2 at the bottom of the mixed tower. It should be noted that the contact surface of the fundamental frequency cable force sensor 4 is parallel to the contact surface of the anchor cable 2 and does not interfere with other structures or equipment; preferably, the fundamental frequency cable force sensor 4 is an acceleration sensor, and the calculation method of the real-time cable force value of the anchor cable is adopted. According to the real-time measurement value of the anchor cable tension F and the transverse seam gap δ of the C-type component within the yaw angle of ±30 degrees, the relative coefficient K between the anchor cable tension and the transverse seam gap of the C-type component is fitted and calibrated, and the relative relationship between the anchor cable tension and the transverse seam gap of the C-type component is obtained, so as to realize the reverse calculation of the physical actual value of the anchor cable tension according to the real-time measurement value of the transverse seam gap of the C-type component of the mixed tower on the same model unit.

[0036] Within the range of yaw angle of ±30 degrees, the actual physical value of anchor cable tension calculated by monitoring the transverse gap of C-type components and wind speed or rotation speed are used to establish a correlation curve, such as Figure 4 As shown, a threshold range of anchor cable tension under different wind speeds or rotation speeds is established (i.e., the lower warning line in the figure). When the actual physical value of the anchor cable tension is lower than the threshold range of the anchor cable tension (i.e., beyond the range of the lower warning line), an abnormal warning of the mixed tower cable tension is issued.

Claims

1. A hybrid tower cable force abnormality monitoring method based on a high-precision displacement sensor is characterized by: The following steps are involved: S1, the C-type components (1) of the mixing tower are firmly connected by applying a tension pre-tightening force through the anchor cables (2) connected up and down, and a high-precision displacement sensor (3) is arranged at the transverse seam of the C-type component (1) of the mixing tower to measure the size of the transverse seam gap of the C-type component of the mixing tower in real time; S2. Collect wind turbine unit operating data, including yaw angle and wind speed or rotation speed; S3, obtaining data of a high-precision displacement sensor (3) within a yaw angle of ±30 degrees, establishing a correlation curve between the transverse seam gap of the C-type component and the wind speed or rotation speed within the yaw angle range, and establishing a transverse seam gap threshold range of the C-type component under different wind speeds or rotation speeds, and when the transverse seam gap of the C-type component exceeds the transverse seam gap threshold range of the C-type component, issuing a transverse seam gap abnormality warning of the C-type component, i.e., a relative cable force abnormality warning; For a mixed tower with external anchor cables, in step S1, a fundamental frequency cable force sensor (4) is also installed on the outer segment of the lower anchor head of the anchor cable (2) at the bottom of the mixed tower to monitor and calculate the real-time cable force value of the anchor cable, that is, the anchor cable tension; according to the real-time measurement value of the anchor cable tension within the yaw angle of ±30 degrees and the transverse seam gap of the C-type component, the relative coefficient between the anchor cable tension and the transverse seam gap of the C-type component is fitted and calibrated to obtain the relative relationship between the anchor cable tension and the transverse seam gap of the C-type component, thereby realizing the reverse calculation of the physical actual value of the anchor cable tension according to the real-time measurement value of the transverse seam gap of the C-type component of the mixed tower on the same model unit.

2. The method for monitoring abnormal cable tension of a mixed tower based on a high-precision displacement sensor according to claim 1 is characterized in that: Within the range of yaw angle of ±30 degrees, a correlation curve is established between the actual physical value of the anchor cable tension calculated by monitoring the transverse seam gap of the C-type component and the wind speed or rotation speed, and a threshold range of the anchor cable tension under different wind speeds or rotation speeds is established. When the actual physical value of the anchor cable tension is lower than the threshold range of the anchor cable tension, an abnormal hybrid tower cable tension warning is issued.

3. The method for monitoring abnormal cable tension of a mixed tower based on a high-precision displacement sensor according to claim 1 is characterized in that: The fundamental frequency cable force sensor (4) is an acceleration sensor.

4. The method for monitoring abnormal cable tension of a mixed tower based on a high-precision displacement sensor according to claim 1 is characterized in that: The high-precision displacement sensor (3) is a micrometer-level displacement sensor.

5. The method for monitoring abnormal cable tension of a mixed tower based on a high-precision displacement sensor according to claim 1 is characterized in that: In step S1, more than four high-precision displacement sensors (3) are arranged at the transverse seams of each C-shaped component (1), and are evenly distributed along the circumference of the mixing tower.

6. The method for monitoring abnormal cable tension of a mixed tower based on a high-precision displacement sensor according to claim 1 is characterized in that: In step S3, the yaw angle range is selected within ±15 degrees.

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