A fan tower monitoring system based on optical fiber strain sensing

Abstract

The application relates to a fan tower tube monitoring system based on an optical fiber strain sensor, the monitoring system comprising a plurality of fixed bases arranged at the top end of a tower tube, at the middle position of the tower tube and between any two tower tubes, a sensor group arranged on the fixed bases and a monitoring terminal connected with the sensor group, optical fiber connection being used between the sensor group and the monitoring terminal, the sensor group comprising a strain sensor, a temperature sensor and an acceleration sensor, the strain sensor, the temperature sensor and the acceleration sensor all being optical fiber sensors. The fan tower tube monitoring system based on the optical fiber strain sensor disclosed in the application uses optical fiber sensors to perform multi-position monitoring on a fan tower tube, the method does not need to additionally provide electric energy, can be deployed at any position and has a relatively long service life.

Description

Technical Field

[0001] This application relates to the field of wind power equipment monitoring technology, and in particular to a wind turbine tower monitoring system based on fiber optic strain sensing. Background Technology

[0002] Wind turbine generators are expensive to manufacture and operate in harsh environments. During operation, they are subjected to a combination of various loads such as vibration, torsion, and shear, which causes varying degrees of wear on key components such as blades and towers, as well as the fasteners connecting these components.

[0003] If early damage is not maintained in time, wear and tear and the spread of damage will cause critical parts to fail, causing the wind turbine to malfunction and stop operating. In severe cases, it can lead to serious accidents such as blade breakage and tower collapse, causing huge economic losses to the operator and even personal injury accidents.

[0004] Taking medium and large wind turbines (medium-sized wind turbines 1~2 MW, large wind turbines 3~5 MW) as an example, the height of the tower is generally between 60 meters and 120 meters, and monitoring needs to be carried out at different heights. If a self-powered monitoring method is adopted, there will be difficulties in power supply and deployment. At the same time, due to the harsh operating environment, the service life of electrical sensors (voltage type, resistance type, capacitive type) will be reduced, and maintenance-free operation during the service life cannot be achieved. Utility Model Content

[0005] This application provides a wind turbine tower monitoring system based on fiber optic strain sensing. It uses fiber optic sensors to monitor the wind turbine tower at multiple locations. This method does not require additional power, can be deployed at any location, and has a long service life.

[0006] The above-mentioned objective of this application is achieved through the following technical solution: This application provides a wind turbine tower monitoring system based on fiber optic strain sensing, comprising: Multiple fixed bases are set at the top of the tower, the middle of the tower, and between any two towers; The sensor assembly is mounted on a fixed base; The monitoring terminal is connected to the sensor array, and the sensor array and the monitoring terminal are connected by optical fiber. The sensor group includes a strain sensor, a temperature sensor, and an acceleration sensor, all of which are fiber optic sensors.

[0007] One possible implementation of this application also includes: The constraint element is located on the inner wall of the tower, and there is a constraint channel on the constraint element; Protective tube, passing through the constraint channel; The restraint rope has one end fixed to the restraint member and the other end fixed to the protective tube.

[0008] In one possible implementation of this application, the length of the protective tube between any two constraint members is greater than the minimum distance between the two constraint members.

[0009] In one possible implementation of this application, the fixed base includes: The base is used to fix it to the tower. The limiting element is slidably connected to the base and is used to apply pressure to the sensor assembly placed on the base.

[0010] In one possible implementation of this application, the limiting member includes a frame that is slidably connected to the base and fasteners provided on the frame.

[0011] In one possible implementation of this application, the fastener is slidably connected to the frame. The sliding direction of the fastener is perpendicular to the sliding direction of the frame.

[0012] In one possible implementation of this application, the strain sensor and temperature sensor are located between any two tower sections, and the acceleration sensor is located at the top of the tower section and the middle of the tower section.

[0013] In one possible implementation of this application, the protective pipe includes multiple rigid pipe segments and flexible sections at both ends that are fixedly connected to adjacent rigid pipe segments.

[0014] The beneficial effects of this application are as follows: The wind turbine tower monitoring system based on fiber optic strain sensing provided in this application can further understand the operating status of the tower by monitoring the deformation and temperature at the tower connection and the overall sway of the tower. It can promptly detect abnormalities in the tower and take timely intervention measures to avoid major safety accidents. Attached Figure Description

[0015] Figure 1 This is a structural schematic diagram of a fixed base provided in this application.

[0016] Figure 2 Based on Figure 1 A structural schematic diagram of the fixed base is provided by adjusting the viewing angle.

[0017] Figure 3 This is an installation diagram of a sensor array provided in this application.

[0018] Figure 4 This is a schematic diagram of a method for constraining optical fibers using a constraint element, as provided in this application.

[0019] Figure 5 This is a schematic diagram of a constraint element with a constraint channel provided in this application.

[0020] Figure 6 This is a structural schematic diagram of a protective tube provided in this application.

[0021] In the diagram, 1 is the fixed base, 2 is the sensor group, 21 is the strain sensor, 22 is the temperature sensor, 23 is the acceleration sensor, 6 is the monitoring terminal, 7 is the constraint component, 11 is the base, 12 is the limiting component, 71 is the constraint channel, 72 is the protective tube, 73 is the constraint rope, 121 is the frame, 122 is the fastener, 721 is the rigid pipe section, and 722 is the flexible section. Detailed Implementation

[0022] The technical solutions in this application will be further described in detail below with reference to the accompanying drawings.

[0023] This application discloses a wind turbine tower monitoring system based on fiber optic strain sensing. For some examples, please refer to... Figures 1 to 3 The wind turbine tower monitoring system based on fiber optic strain sensing disclosed in this application includes a fixed base 1, a sensor group 2, and a monitoring terminal 6. The fixed base 1 can be installed in three locations: between any two tower sections, at the top of the tower section, and in the middle of the tower section.

[0024] Sensor group 2 includes strain sensor 21, temperature sensor 22, and acceleration sensor 23. The types of sensors included in sensor group 2 differ depending on the position of the fixed base 1. The specific differences are as follows: Strain sensor 21 and temperature sensor 22 are located on fixed base 1 between any two tower sections; Accelerometer 23 is located on a fixed base 1 at the top and middle of the tower.

[0025] The strain sensor 21, temperature sensor 22, and acceleration sensor 23 all use fiber optic sensors and are connected to the monitoring terminal 6 via fiber optic cables. Fiber optic sensors are non-metallic products, which helps reduce the impact of electromagnetic interference such as lightning strikes on fiber optic transmission equipment, resulting in higher reliability and a longer service life.

[0026] The strain sensor 21 mainly reflects the deformation and deformation process at the connection point. This can be described as the change in the relative position of the two connected towers. This change will cause irreversible deformation, cracks and mechanical fatigue at the connection point of the two towers, and will also weaken the strength of the connecting components at the connection point.

[0027] Temperature sensor 22 mainly reflects the surface temperature of the structure and is used to correct the value of strain sensor 21, so that strain sensor 21 reflects the deformation of the structure under the influence of external force, rather than thermal expansion and contraction deformation. This is because the feedback result of temperature sensor 22 is related to its environment and needs to be corrected by the ambient temperature.

[0028] Accelerometer 23 mainly reflects the swaying of the tower, including vibration frequency and amplitude.

[0029] Specifically, through data analysis, the natural frequency of tower sway can be monitored. By monitoring the change of the tower's natural frequency over time, the degradation of the tower's stiffness can be reflected, thereby judging the damage situation and assessing aging, local crack damage, etc., after long-term operation of the tower.

[0030] By combining the vibration frequency and amplitude monitored by the two acceleration sensors 23, the actual sway and mode shape of the tower top relative to the equilibrium position can be calculated, which is beneficial for real-time monitoring of the overall safety of the tower.

[0031] In some examples, please refer to Figure 1 and Figure 2 The fixed base 1 includes a base 11 and a limiting member 12. The base 11 is fixed to the tower, for example by adhesive bonding. The limiting member 12 is slidably connected to the base 11. Its function is to apply pressure to the strain sensor 21, temperature sensor 22 or acceleration sensor 23 placed on the base 11, thereby fixing the strain sensor 21, temperature sensor 22 or acceleration sensor 23 to the base 11.

[0032] The limiting component 12 includes a frame 121 that is slidably connected to the base 11 and a fastener 122 provided on the frame 121. The frame 121 is used for position adjustment and to provide support for the fastener 122.

[0033] The fastener 122 is connected to the frame 121 by a sliding connection, and the sliding direction of the fastener 122 is perpendicular to the direction of the frame 121. Here, the sliding method of the frame 121 can be called longitudinal sliding, and the sliding method of the fastener 122 can be called transverse sliding.

[0034] The frame 121 and fastener 122 can be adjusted in position by sliding, which is used to fix the sensor groups 2 of different specifications. Generally, at least one sensor is deployed at a fixed base 1 position, and at least one set of spare sensors may also be added. For convenience, these sensors are generally fixed on a mounting plate. The frame 121 and fastener 122 are moved to the appropriate position to fix the mounting plate.

[0035] Additionally, a spare recess will be added to the mounting plate for installing a new sensor when the old one fails. Figure 3 As shown, the mounting plate has 6 grooves. New sensors can be directly installed in the empty grooves and then fixed by means of the threaded holes below the grooves.

[0036] The monitoring terminal 6 is also deployed inside a platform or box inside the tower. The monitoring terminal 6 consists of two parts: a spectrometer and a processor. The spectrometer can use a demodulator module from Bayer or a miniaturized spectrometer module from A53. The processor can be an industrial computer for processing. Data communication between the spectrometer and the processor can be completed using a communication module (QJ-12RGT-O1Z-24V).

[0037] The strain sensor 21, temperature sensor 22, and acceleration sensor 23 are all connected to the monitoring terminal 6 via optical fibers. The optical fibers that are suspended or fixed with fasteners may be damaged during long-term use due to factors such as large-scale shaking or pulling.

[0038] To resolve this issue, please refer to Figure 4 and Figure 5 In some examples, a constraint member 7, a protective tube 72, and a constraint rope 73 are added. The constraint member 7 is fixed to the inner wall of the tower. The constraint member 7 has constraint channels 71. The protective tube 72 passes through each constraint channel 71 sequentially. The function of the constraint channel 71 is to limit the range of motion of the protective tube 72. Here, the diameter of the protective tube 72 needs to be smaller than the inner diameter of the constraint channel 71, with a difference of 5-10 mm.

[0039] The first end of the constraint rope 73 is fixed to the constraint member 7, and the second end is fixed to the protective tube 72. The function of the constraint rope 73 is to connect the protective tube 72. The specific reason is that when the length of the protective tube 72 is too long, its weight will be borne by the connection between the sensor group 2 and the optical fiber, which will cause the connection to be overloaded.

[0040] After using the constraint rope 73, the weight of the protective tube 72 is transferred to the constraint member 7. This allows the connection between the sensor group 2 and the optical fiber to be free from weight load, and the length of the optical fiber at this point can be appropriately increased to compensate for the distance change caused by relative displacement, thus preventing tension at the connection between the sensor group 2 and the optical fiber.

[0041] Furthermore, such as Figure 6As shown, the protective tube 72 includes a rigid tube section 721 and a flexible section 722. The rigid and flexible sections are arranged alternately. The function of the flexible section 722 is to reduce the length of a single rigid tube section 721, which can prevent the protective tube 72 from shaking significantly to a certain extent and prevent the optical fiber inside the protective tube 72 from being straightened, thus playing an effective protective role.

[0042] In some possible implementations, the length of the protective tube 72 between any two constraint members 7 is greater than the minimum distance between the two constraint members 7. This allows the protective tube 72 to have a certain margin when it shakes, which can prevent the optical fiber inside the protective tube 72 from being pulled. This is achieved by means of a constraint rope 73.

[0043] In some possible implementations, the optical fiber inside the protective tube 72 is fixed to the inner wall of the protective tube 72 using clips. Specifically, the optical fiber is first fixed to the clips, then the clips are glued to the inner wall of the rigid tube segment 721 of the protective tube 72, and then a flexible joint 722 is used to connect the two rigid tube segments 721.

[0044] The embodiments described in this specific implementation are preferred embodiments of this application and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A wind turbine tower monitoring system based on fiber optic strain sensing, characterized in that, include: Multiple fixed bases (1) are set at the top of the tower, at the middle of the tower, and between any two towers; The sensor assembly (2) is mounted on the fixed base (1); The monitoring terminal (6) is connected to the sensor group (2), and the sensor group (2) and the monitoring terminal (6) are connected by optical fiber; The sensor group (2) includes a strain sensor (21), a temperature sensor (22) and an acceleration sensor (23), all of which are fiber optic sensors.

2. The wind turbine tower monitoring system based on fiber optic strain sensing according to claim 1, characterized in that, Also includes: The constraint member (7) is located on the inner wall of the tower, and the constraint member (7) has a constraint channel (71). The protective tube (72) passes through the restraint channel (71); The first end of the restraint rope (73) is fixed to the restraint member (7), and the second end is fixed to the protective tube (72).

3. The wind turbine tower monitoring system based on fiber optic strain sensing according to claim 2, characterized in that, The length of the protective tube (72) between any two constraint members (7) is greater than the minimum distance between the two constraint members (7).

4. The wind turbine tower monitoring system based on fiber optic strain sensing according to any one of claims 1 to 3, characterized in that, The fixed base (1) includes: The base (11) is used to fix it to the tower tube; The limiting member (12) is slidably connected to the base (11) and is used to apply pressure to the sensor group (2) placed on the base (11).

5. The wind turbine tower monitoring system based on fiber optic strain sensing according to claim 4, characterized in that, The limiting member (12) includes a frame (121) that is slidably connected to the base (11) and a fastener (122) provided on the frame (121).

6. The wind turbine tower monitoring system based on fiber optic strain sensing according to claim 5, characterized in that, Fastener (122) is slidably connected to frame (121); The sliding direction of the fastener (122) is perpendicular to the sliding direction of the frame (121).

7. The wind turbine tower monitoring system based on fiber optic strain sensing according to claim 1, characterized in that, The strain sensor (21) and temperature sensor (22) are located between any two tower sections, and the acceleration sensor (23) is located at the top of the tower section and the middle of the tower section.

8. The wind turbine tower monitoring system based on fiber optic strain sensing according to claim 2, characterized in that, The protective pipe (72) includes multiple rigid pipe sections (721) and flexible sections (722) that are fixedly connected at both ends to adjacent rigid pipe sections (721).

Images