Fiber bragg grating sensor for monitoring deformation of wind power tower

Abstract

The utility model relates to a fiber bragg grating sensor used for wind power tower deformation monitoring, comprising a sensor body, the sensor body comprises a fiber bragg grating, a sleeve body, a penetrating movable steel pipe, a transmission separator plate and a connecting steel pipe, the penetrating movable steel pipe is arranged on the sleeve body through the transmission separator plate in a sliding fit manner, and the connecting steel pipe is arranged on the transmission separator plate. The fiber bragg grating is arranged on the connecting steel pipe and penetrates through the two sides of the axial sleeve body, displacement sensors are arranged on the two sides of the fiber bragg grating, and when the two sides of the sensor body receive pressure or tension, the penetrating movable steel pipe can drive the transmission partition plate to push together along with different pressure or tension, so that the connecting steel pipe can be correspondingly stretched or compressed; the fiber bragg grating penetrates through the displacement sensors on the two sides to detect different deformation values, and then changes of the wavelength in the fiber bragg grating are reflected. The sensor can monitor the change of stress according to external stretching or compression (the pressure changes).

Description

Technical Field

[0001] The utility model relates to the technical field of wind power tower deformation monitoring, in particular to a fiber grating sensor used for wind power tower deformation monitoring. Background Art

[0002] Wind tower deformation monitoring is a key technology that aims to monitor and evaluate the deformation of wind tower structures in real time. Since wind towers are subjected to wind loads, deadweight and other external factors, their structures may deform to a certain extent, such as tilt, deflection and deformation.

[0003] The context of this monitoring work is important for the following reasons:

[0004] First of all, the wind turbine tower is a vital component of the wind power generation system. The structural stability and safety of the tower are directly related to the reliability and operational safety of the entire power generation system. By monitoring the deformation of the tower in real time, potential structural problems can be discovered in time, and corresponding measures can be taken to repair them to ensure the stability and safety of the tower.

[0005] Secondly, the deformation of the tower may affect the operating efficiency of the wind turbine. The inclination, deflection and deformation of the tower may cause the turbine to deviate from the designed operating conditions, thus affecting the power generation efficiency. By monitoring the deformation in real time, these adverse effects can be discovered and corrected in time, thereby improving the operating efficiency and power generation of the wind power generation system.

[0006] Finally, deformation monitoring is critical for tower maintenance management. By collecting and analyzing deformation data, a scientific and reasonable maintenance plan can be formulated, and the timing of maintenance can be accurately determined to avoid greater losses due to untimely treatment. This effective maintenance management will help extend the service life of wind turbine towers and reduce maintenance costs. Deformation monitoring of wind turbine towers is an important means to ensure the structural safety of wind power generation systems, improve operating efficiency, and optimize maintenance management.

[0007] Therefore, how to provide reliable data support through real-time monitoring and analysis of tower deformation is a technical problem that needs to be solved urgently. Utility Model Content

[0008] In view of this, the utility model provides a fiber grating sensor for monitoring deformation of wind power towers, which can monitor and analyze the deformation of towers in real time through fiber grating (FBG), and provide reliable data support.

[0009] The utility model provides a fiber grating sensor for wind power tower deformation monitoring using the following technical solutions:

[0010] A fiber grating sensor for monitoring deformation of a wind power tower comprises a sensor body, wherein the sensor body comprises a fiber grating, a sleeve body, a penetrating movable steel pipe, a transmission partition and a connecting steel pipe, wherein the penetrating movable steel pipe is slidably fitted on the sleeve body through the transmission partition, the connecting steel pipe is arranged on the transmission partition, the fiber grating is arranged on the connecting steel pipe, the fiber grating penetrates both sides of the sleeve body along the axial direction, and displacement sensors are arranged on both sides of the fiber grating. When both sides of the sensor body receive pressure or tension, the penetrating movable steel pipe will drive the transmission partition to push together with the different pressure or tension, so that the connecting steel pipe will also be stretched or compressed accordingly, so that the displacement sensors penetrating both sides of the fiber grating detect different deformation values, thereby reflecting the change of wavelength in the fiber grating.

[0011] Optionally, transmission partitions are provided at both ends of the sleeve body, a movable steel pipe is provided on one transmission partition, a movable steel pipe is provided on the other transmission partition, and a built-in transmission steel pipe is provided on the transmission partition located on one side of the movable steel pipe. The built-in transmission steel pipe is spaced apart from the transmission partition located on one side of the movable steel pipe.

[0012] Optionally, a fiber Bragg grating clamping tube and a fiber Bragg grating mounting support frame are respectively provided at both ends of the fiber Bragg grating, and the fiber Bragg grating is arranged on the connecting steel pipe through the fiber Bragg grating clamping tube and the fiber Bragg grating mounting support frame.

[0013] Optionally, the deformation and strain of the fiber Bragg grating clamping tube and the fiber Bragg grating are expressed as:

[0014]

[0015]

[0016] (where P g , P f is the internal force of the FBG clamping tube and the FBG, L and L f is the distance between the FBG clamping tube and the FBG mounting support and the length of the FBG, E g 、E f is the Young's modulus of the fiber Bragg grating holding tube and the fiber Bragg grating, A g , A f is the cross-sectional area of ​​the fiber Bragg grating clamping tube and the fiber Bragg grating. Since the sensor can be approximated as a double-force rod that is only subjected to axial force, the internal force of each part can be regarded as equal, so P g Equal to P f . )

[0017] Optionally, the sleeve body includes an outer sleeve and an inner upper sleeve and an inner lower sleeve arranged at two ends of the outer sleeve.

[0018] Optionally, the inner upper sleeve and the inner lower sleeve are connected to the outer sleeve via threads.

[0019] Optionally, the fiber grating is adhered to the outer contour of the connecting steel pipe.

[0020] In summary, the present invention includes at least one of the following beneficial technical effects: BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is an overall schematic diagram of the wind power tower fiber grating sensor of this embodiment;

[0022] Figure 2 This is a schematic diagram of the internal cross-section of the fiber grating sensor of the wind power tower of this embodiment;

[0023] Figure 3 This is a schematic diagram of the fiber Bragg grating pasting of the fiber Bragg grating sensor on the wind turbine tower of this embodiment.

[0024] Explanation of the reference numerals: 1. Fiber Bragg grating; 2. Outer sleeve; 3. Inner upper sleeve; 4. Inner lower sleeve; 5. Through steel pipe; 6. Connecting steel pipe; 7. Built-in transmission steel pipe; 8. Transmission partition; 9. Through movable steel pipe; 10. Fiber Bragg grating clamping tube; 11. Fiber Bragg grating mounting support frame. DETAILED DESCRIPTION

[0025] The following is combined with Figure 1-3 The utility model is described in further detail.

[0026] The utility model embodiment discloses a fiber grating sensor for monitoring deformation of a wind power tower.

[0027] Reference Figure 1 , Figure 2 , Figure 3 A fiber grating sensor for wind power tower deformation monitoring includes a sensor body, the sensor body includes a fiber grating 1, a sleeve body, a penetrating movable steel pipe 9, a transmission partition 8 and a connecting steel pipe 6, the penetrating movable steel pipe 9 is slidably arranged on the sleeve body through the transmission partition 8, the connecting steel pipe 6 is arranged on the transmission partition 8, the fiber grating 1 is arranged on the connecting steel pipe 6, the fiber grating 1 penetrates both sides of the sleeve body along the axial direction, and displacement sensors are arranged on both sides of the fiber grating 1. When the two sides of the sensor body receive pressure or tension, the penetrating movable steel pipe 9 will drive the transmission partition 8 to push together with the different pressure or tension, so that the connecting steel pipe 6 will also be stretched or compressed accordingly, so that the displacement sensors on both sides of the fiber grating 1 detect different deformation values, thereby reflecting the change of wavelength in the fiber grating 1. The sensor can monitor the change of stress according to external tension or compression (pressure change).

[0028] The fiber Bragg grating 1 is passed through both sides of the sleeve. When the outside is stretched or compressed, the connecting steel pipe 6 to which the fiber Bragg grating is pasted is also stretched or compressed, so that the displacement meter connected to both sides of the fiber Bragg grating 1 detects the displacement. The physical quantity sensed by the displacement meter of the fiber Bragg grating 1 is converted into an electrical signal. After analog signal processing or digital signal processing, the electrical signal is converted into a readable digital signal or data.

[0029] In this embodiment, the displacement sensor is a displacement meter.

[0030] In this embodiment, transmission partitions 8 are provided at both ends of the sleeve body, a movable steel pipe 9 is provided on one transmission partition 8, and a movable steel pipe is provided on the other transmission partition 8. A built-in transmission steel pipe 7 is provided on the transmission partition 8 located on one side of the movable steel pipe, and the built-in transmission steel pipe 7 is spaced apart from the transmission partition 8 located on the side of the movable steel pipe 9.

[0031] In this embodiment, the fiber grating 1 is pasted to the outer contour of the connecting steel pipe 6. The two ends of the fiber grating 1 are respectively provided with a fiber grating clamping tube 10 and a fiber grating mounting support frame 11, and the fiber grating 1 is arranged on the connecting steel pipe 6 through the fiber grating clamping tube 10 and the fiber grating mounting support frame 11.

[0032] In this embodiment, the sleeve body includes an outer sleeve 2 and an inner upper sleeve 3 and an inner lower sleeve 4 disposed at both ends of the outer sleeve 2. Specifically, the inner upper sleeve 3 and the inner lower sleeve 4 are connected to the outer sleeve 2 by threads. According to actual use requirements, outer sleeves 2, inner upper sleeves 3 and inner lower sleeves 4 of different sizes or multiple sleeve bodies can be selected for use, and the number of sleeve bodies can be freely increased or decreased according to the length of the monitored object, so that the overall length of the sensor can be adjusted. Improve applicability.

[0033] The fiber grating is passed through both sides of the sleeve. When the outside is stretched or compressed, the connecting steel pipe 6 is also stretched or compressed, so that the displacement sensors connected to both sides of the fiber grating 1 detect the displacement. The physical quantity sensed by the fiber grating displacement sensor is converted into electrical signals. These electrical signals are converted into readable digital signals or data after analog signal processing or digital signal processing.

[0034] Since the adhesive thickness is smaller than the fiber diameter, the stress transmission loss between the epoxy resin and the fiber can be ignored. Since the fiber Bragg grating 1 is mounted on the structural surface through two mounting supports, the fiber area has no contact with the epoxy resin, so the fiber Bragg grating 1 strain sensor eliminates multiple peaks of reflected light caused by the uneven bonding distribution of the epoxy resin. Therefore, the deformation and strain of the fiber Bragg grating clamping tube 10 and the fiber Bragg grating 1 can be expressed as:

[0035]

[0036]

[0037] (where P g , P f is the internal force of the clamping tube and FBG, L and L f is the distance between the two mounting supports (in this embodiment, the FBG clamping tube 10 and the FBG mounting support frame 11) and the length of the FBG, E g 、E f is the Young's modulus of the fiber Bragg grating holding tube 10 and the fiber Bragg grating, A g , A f is the cross-sectional area of ​​the fiber Bragg grating holding tube 10 and the fiber Bragg grating. Since the sensor can be approximated as a double-force rod that is only subjected to axial force, the internal force of each part can be considered equal, so P g Equal to P f . )

[0038] When the light source is incident on the Bragg grating, the Bragg condition is met, that is, the reflected wavelength of the light must satisfy:

[0039] λ B =2n eff Λ (3)

[0040] (where λ B is the central wavelength of the fiber Bragg grating, n eff is the effective refractive index of the fiber core, Λ is the Bragg grating period)

[0041] When the environment and temperature change:

[0042] Δλ / λ=[(1-P e )ε+(α+ξ)ΔT] (4)

[0043] (where λ is the initial wavelength of the fiber Bragg grating, Δλ is the wavelength change, ε is the axial strain of the fiber Bragg grating, P is the effective elastic-optic coefficient of the fiber, α is the thermal expansion coefficient of the fiber, ξ is the thermal-optic coefficient of the fiber, and ΔT is the temperature change)

[0044] This fiber Bragg grating sensor eliminates the influence of temperature. According to formulas (1)-(4), the wavelength change Δλ of the fiber Bragg grating sensor and the fiber Bragg grating internal force P can be obtained: f Relationship:

[0045]

[0046] It can be seen that the wavelength change Δλ is related to the fiber Bragg grating internal force P fThere is a certain functional relationship, that is, when the connecting steel pipe 6 in the sensor is subjected to pressure or tension, the displacement captured by the displacement meters on both sides can be used to deduce the internal force of the fiber grating, and then the wavelength change in the fiber grating can be obtained, thereby achieving the monitoring purpose of this fiber grating sensor for wind tower deformation monitoring.

[0047] When the two sides of the sensor body are subjected to different degrees of tension and compression, the movable steel pipe 9 penetrating through it will drive the transmission partition 8 to push along with the different pressures or tensions, and then the connecting steel pipe 6 will also be stretched or compressed. The displacement sensors penetrating through the two sides of the fiber grating detect different deformation values, which can reflect the changes in the wavelength of the fiber grating.

[0048] The sensor of the utility model can monitor the change of stress according to external stretching or compression (pressure change).

[0049] The above are all preferred embodiments of the present utility model, and are not intended to limit the protection scope of the present utility model. Therefore, any equivalent changes made based on the structure, shape, and principle of the present utility model should be included in the protection scope of the present utility model.

Claims

1. A fiber grating sensor for wind turbine tower deformation monitoring, characterized in that: The sensor body includes a fiber grating, a sleeve body, a penetrating movable steel pipe, a transmission partition and a connecting steel pipe. The penetrating movable steel pipe is slidably fitted on the sleeve body through the transmission partition, the connecting steel pipe is arranged on the transmission partition, the fiber grating is arranged on the connecting steel pipe, the fiber grating penetrates both sides of the sleeve body along the axial direction, and displacement sensors are arranged on both sides of the fiber grating. When both sides of the sensor body receive pressure or tension, the penetrating movable steel pipe will drive the transmission partition to push together with the different pressure or tension, so that the connecting steel pipe will also be stretched or compressed accordingly, so that the displacement sensors on both sides of the fiber grating penetrated by the fiber grating detect different deformation values, thereby reflecting the change of wavelength in the fiber grating.

2. The fiber grating sensor for wind turbine tower deformation monitoring according to claim 1, characterized in that: Transmission partitions are provided at both ends of the sleeve body, a movable steel pipe is provided on one transmission partition, and a movable steel pipe is provided on the other transmission partition. A built-in transmission steel pipe is provided on the transmission partition located on one side of the movable steel pipe, and the built-in transmission steel pipe is spaced apart from the transmission partition located on one side of the movable steel pipe.

3. The fiber grating sensor for wind turbine tower deformation monitoring according to claim 2, characterized in that: The two ends of the fiber grating are respectively provided with a fiber grating clamping tube and a fiber grating mounting support frame, and the fiber grating is arranged on the connecting steel pipe through the fiber grating clamping tube and the fiber grating mounting support frame.

4. The fiber grating sensor for wind turbine tower deformation monitoring according to claim 3 is characterized in that: The deformation and strain of the fiber Bragg grating holding tube and the fiber Bragg grating are expressed as: Where P g , P f is the internal force of the FBG clamping tube and the FBG, L and L f is the distance between the FBG clamping tube and the FBG mounting support and the length of the FBG, E g 、E f is the Young's modulus of the fiber Bragg grating holding tube and the fiber Bragg grating, A g , A f is the cross-sectional area of ​​the fiber Bragg grating clamping tube and the fiber Bragg grating. Since the sensor can be approximated as a double-force rod that is only subjected to axial force, the internal force of each part can be considered equal, so P g Equal to P f .

5. The fiber grating sensor for wind turbine tower deformation monitoring according to claim 3 is characterized in that: The sleeve body comprises an outer sleeve and an inner upper sleeve and an inner lower sleeve which are arranged at two ends of the outer sleeve.

6. The fiber grating sensor for wind turbine tower deformation monitoring according to claim 5, characterized in that: The inner upper sleeve and the inner lower sleeve are connected to the outer sleeve through threads.

7. The fiber grating sensor for wind turbine tower deformation monitoring according to claim 2, characterized in that: The fiber grating is pasted to the outer contour of the connecting steel pipe.

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