Wind power blade root load monitoring device

Abstract

The utility model relates to the technical field of optical fiber sensing technology and wind power blade root load monitoring, in particular to a wind power blade root load monitoring device which comprises a wind power blade root body. The fiber bragg grating array comprises a first fiber bragg grating measuring point, a second fiber bragg grating measuring point, a third fiber bragg grating measuring point, a fourth fiber bragg grating measuring point, a fifth fiber bragg grating measuring point, a sixth fiber bragg grating measuring point and an optical fiber patch cord which are located in a wind power blade root body, and one end close to the fourth fiber bragg grating measuring point is arranged as a PS end connecting end. According to the utility model, the fiber bragg grating array is embedded into the blade root of the wind power blade, so that the probability that the fiber bragg grating array is damaged, falls off and fails is greatly reduced, and the measurement accuracy of the fiber bragg grating array is improved. And the reliability and the stability of load measurement are greatly improved.

Description

Technical Field

[0001] The utility model relates to the fields of optical fiber sensing technology and wind turbine blade load monitoring technology, in particular to a wind turbine blade root load monitoring device. Background Art

[0002] Currently, wind turbines are developing towards lighter weight, higher speed, and heavier loads. These requirements place greater demands on blade operating length and parameters, and the natural conditions in which they operate are becoming increasingly harsh. Blades not only endure constant alternating loads but are also subject to frequent impacts from flying rocks, as well as erosion and erosion from external factors such as airflow and ultraviolet radiation. This can easily lead to mechanical damage such as delamination, cracks, and wear, affecting the blade's mechanical properties and directly threatening wind turbine performance, operational safety, and power generation quality. This is also a major cause of other failures and economic losses. Data indicates that blade failures account for over 65% of wind turbine failures, and the resulting incidents are often severe, resulting in significant losses.

[0003] With the increasing maturity of fiber Bragg grating manufacturing technology and the improvement of fiber Bragg grating demodulation technology, fiber Bragg grating technology is increasingly being used in the field of wind power monitoring, especially in the field of blade structure health monitoring, because of its many advantages such as resistance to electromagnetic interference, corrosion resistance, lightning resistance, direct absolute wavelength encoding, no influence from optical power fluctuations, good long-term reliability and stability, long-distance signal transmission, wavelength division multiplexing networking, and application in flammable and explosive environments.

[0004] Blade root load monitoring can detect the stress conditions on wind turbine blades and monitor parameters such as blade load (bending moment and torque) and fatigue damage. It is currently the primary focus of blade structure monitoring. Existing sensors and wind turbine blades are typically connected by gluing the blades onto the surface after they are formed. The drawback of this approach is that, due to the repeated alternating loads (such as impact, random, and cyclic loads) and alternating hot and cold temperatures that blades endure during operation, the bonding surface between the sensor and the blade can easily separate, resulting in invalid measurement data and even sensor damage. Utility Model Content

[0005] The purpose of the present utility model is to provide a wind turbine blade root load monitoring device to solve the problems raised in the above background technology.

[0006] To achieve the above objectives, the present invention provides the following technical solutions:

[0007] A wind turbine blade root load monitoring device includes a wind turbine blade root body, wherein a fiber grating array is sequentially arranged inside the wind turbine blade root body, the fiber grating array including a fiber grating measuring point No. 1, a fiber grating measuring point No. 2, a fiber grating measuring point No. 3, a fiber grating measuring point No. 4, a fiber grating measuring point No. 5, a fiber grating measuring point No. 6, and a fiber jumper located inside the wind turbine blade root body, wherein the fiber grating measuring point No. 1, the fiber grating measuring point No. 2, the fiber grating measuring point No. 3, the fiber grating measuring point No. 4, the fiber grating measuring point No. 5, and the fiber grating measuring point No. 6 are respectively connected by fiber jumpers, an end close to the fiber grating measuring point No. 4 is set as a PS terminal connection end, an end close to the fiber grating measuring point No. 3 is set as a demodulator connection end, and an end close to the fiber grating measuring point No. 1 is set as an SS terminal connection end.

[0008] As a preferred solution of the present invention, the fiber optic jumper connected only at one end is connected to a pigtail, a fiber optic protection tube is provided on the outside of the pigtail, a connector is fixedly connected to the side of the fiber optic protection tube, and a plurality of fiber-reinforced composite material bundle layers and epoxy resin layers are sequentially provided on the outside of the fiber grating array.

[0009] As a preferred solution of the present invention, the fiber grating array is arranged in the axial direction of the fan blade for monitoring the axial load, the circumferential direction of the fan blade for monitoring the circumferential load, and the 45° direction for monitoring the torsional load. The central reflection wavelengths of the fiber gratings of the fiber grating array are different, and the wavelength intervals between them are preferably greater than 3nm.

[0010] As a preferred solution of the present invention, the optical fiber protection tube can be a rubber tube or a plastic tube. The diameter of the optical fiber protection tube is preferably between 2mm and 3.5mm, and the inner diameter of the optical fiber protection tube is preferably between 2mm and 3mm.

[0011] As a preferred solution of the present invention, the fiber grating array is composed of n (n≥2) single fiber gratings, and the fiber grating array is directly laser-written on the optical fiber without removing the coating layer using existing technology.

[0012] As a preferred solution of the present invention, the demodulator connection end is connected to the fiber grating demodulator, and the fiber grating array is connected to the communication system of the wind turbine through an Ethernet cable, and then completes data interaction with the server of the wind turbine wind turbine blade root structure monitoring system software platform of the wind farm's centralized control center.

[0013] As a preferred solution of the present invention, the wind turbine blade root structure monitoring system software platform uses the modbus / TCP protocol and a fiber grating demodulator to read stress monitoring data for display, processing, storage and information alarm.

[0014] As an optimal solution of the present invention, the wind turbine blade root structure monitoring system software platform is a B / S architecture, and the wind turbine blade root structure monitoring system software is deployed on the server of the wind turbine control center and the cloud server in the cloud, both of which can be remotely accessed.

[0015] Compared with the prior art, the beneficial effects of the present invention are:

[0016] 1. In the present invention, compared with the prior art, on the one hand, the fiber grating array is embedded into the root body of the wind turbine blade, and the various components of the fiber grating array will not be damaged or fall off, the probability of failure is very small, and the reliability and stability of load measurement are greatly improved. On the other hand, it also improves the production efficiency of the wind turbine blade root body and improves the practical performance.

[0017] 2. Compared with the existing technology, the fiber grating array in the present invention has no breakpoints and does not require fiber fusion splicing. It can measure multiple load measurement points on one optical fiber, which improves the accuracy of the data and makes the data more representative. It can timely monitor and maintain parameters such as the root load (bending moment and torque) and fatigue damage of wind turbine blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the fiber Bragg grating array connected to the SS end of the utility model;

[0019] Figure 2 This is a schematic diagram of the fiber Bragg grating array connected to the PS end of the utility model;

[0020] Figure 3 A schematic cross-sectional view of the present invention.

[0021] In the figure: 1. Fiber Bragg grating measurement point No. 1; 2. Fiber Bragg grating measurement point No. 2; 3. Fiber Bragg grating measurement point No. 3; 4. Fiber Bragg grating measurement point No. 4; 5. Fiber Bragg grating measurement point No. 5; 6. Fiber Bragg grating measurement point No. 6; 7. PS end connection end; 8. Demodulator connection end; 9. SS end connection end; 10. Pigtail; 11. Fiber optic protection tube; 12. Connector; 13. Epoxy resin layer; 14. Multiple fiber reinforced composite material bundle layer; 15. Wind turbine blade root body; 16. Fiber jumper; 17. Fiber Bragg grating array. DETAILED DESCRIPTION

[0022] The following will combine the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0023] For examples, see Figure 1-3 , the utility model provides a technical solution:

[0024] A wind turbine blade root load monitoring device includes a wind turbine blade root body 15, a fiber grating array 17 is sequentially arranged inside the wind turbine blade root body 15, and the fiber grating array 17 includes a fiber grating measuring point 1 No. 1, a fiber grating measuring point 2 No. 2, a fiber grating measuring point 3 No. 3, a fiber grating measuring point 4 No. 4, a fiber grating measuring point 5 No. 5, a fiber grating measuring point 6 No. 6 and an optical fiber jumper 16 located inside the wind turbine blade root body 15, and a fiber grating measuring point 1 No. 1, a fiber grating measuring point 2 No. 3, a fiber grating measuring point 3 No. 4, a fiber grating measuring point 4 No. 5, a fiber grating measuring point 6 No. 6 and an optical fiber jumper 16. The fiber grating measuring points 6 are connected to each other through fiber jumpers 16 respectively, the end close to the fiber grating measuring point 4 No. 4 is set as the PS end connection end 7, the end close to the fiber grating measuring point 3 No. 3 is set as the demodulator connection end 8, and the end close to the fiber grating measuring point 1 No. 1 is set as the SS end connection end 9. The fiber jumper 16 connected only at one end is connected to a pigtail 10, and a fiber optic protection tube 11 is set on the outside of the pigtail 10, and a connector 12 is fixedly connected to the side of the fiber optic protection tube 11. A plurality of fiber reinforced composite material bundle layers 14 and epoxy resin layers 13 are sequentially arranged on the outside of the fiber grating array 17.

[0025] In this embodiment, Figure 1 、 Figure 2 and Figure 3 As shown, the fiber Bragg gratings of the fiber Bragg grating array are arranged in the axial direction of the fan blade for monitoring the axial load, the circumferential direction of the fan blade for monitoring the circumferential load, and the 45° direction for monitoring the torsional load. The central reflection wavelengths of the fiber Bragg gratings of the fiber Bragg grating array are different, and the wavelength interval between each other is preferably greater than 3nm. The optical fiber protection tube 11 can be a rubber tube or a plastic tube. The diameter of the optical fiber protection tube 11 is preferably between 2mm-3.5mm, and the inner diameter of the optical fiber protection tube 11 is preferably between 2mm-3mm. The fiber Bragg grating array 17 is composed of n (n≥2) single optical fiber Bragg gratings. The fiber Bragg grating array 17 is directly laser-written on the optical fiber without removing the coating layer using existing technology.

[0026] Among them, compared with the existing technology, on the one hand, the fiber grating array 17 is embedded in the wind turbine blade root body 15, and the various components of the fiber grating array 17 will not be damaged or fall off, the probability of failure is very small, and the reliability and stability of load measurement are greatly improved. On the other hand, it also improves the production efficiency of the wind turbine blade root and improves practical performance.

[0027] In this embodiment, Figure 1 and Figure 2 As shown, the demodulator connection terminal 8 and the fiber Bragg grating demodulator are connected together, and the fiber Bragg grating array 17 is connected to the communication system of the wind turbine through an Ethernet cable, and then completes data interaction with the server of the wind turbine wind turbine blade root structure monitoring system software platform of the wind farm's centralized control center. The wind turbine wind turbine blade root structure monitoring system software platform reads stress monitoring data through the modbus / TCP protocol and the fiber Bragg grating demodulator, and performs display, processing, storage and information alarm. The wind turbine wind turbine blade root structure monitoring system software platform is a B / S architecture. The wind turbine wind turbine blade root structure monitoring system software is deployed on the server of the wind turbine centralized control center and the cloud server in the cloud, both of which can be remotely accessed.

[0028] Among them, compared with the existing technology, the fiber grating array 17 has no breakpoints and does not require fiber fusion splicing. It can measure multiple load measurement points on one optical fiber, which improves the accuracy of the data and makes the data more representative. It can timely monitor and maintain parameters such as the root load (bending moment and torque) and fatigue damage of wind turbine blades.

[0029] The working process of the utility model is as follows: when a wind turbine blade root load monitoring device designed by the present invention is in operation, first, on the wind turbine blade root prefabricated part mold, cleaning, spraying a demoulding agent, laying a demoulding cloth and other processes are carried out, and then a lower layer of glass fiber cloth is laid. After the number of layers is determined according to the design requirements, the fiber optic grating array 17 is laid on the lower layer of glass fiber cloth according to the designed layout measurement point position, and is preliminarily fixed using the existing technology, and then the upper layer of glass fiber cloth is laid on top of the fiber optic grating array 17 and the lower layer of glass fiber cloth; the optical fiber protection tube 11 is put on the outside of the pigtail 10, and protective measures are taken, and then the demoulding cloth, guide net and vacuum film are laid, a vacuum environment is established, epoxy resin is injected, and then heat-insulated and cured to form an epoxy resin layer 13. After demoulding, the pigtail 10 is connected to the optical fiber jumper 16. And take protective measures to form a wind turbine blade root preform embedded with a fiber grating array, and then embed the wind turbine blade root preform into the blade root through existing technology and install it on the wind turbine, connect the fiber grating demodulator set in the wind turbine hub and the wind turbine blade root preform embedded with the fiber grating array 17 through the connector 12, collect and calculate the load information of different measuring points at the blade root, set the wireless data transceiver fiber grating measuring point in the wind turbine cabin, communicate data with the fiber grating demodulator through the WiFi network, and communicate with the system workstation set in the wind farm control room through the wind farm optical fiber communication network, the wind turbine blade root structure monitoring system platform is installed in the system workstation, and performs data, storage, display, alarm and other operations on the blade root load information.

[0030] Although the embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A wind turbine blade root load monitoring device, comprising a wind turbine blade root body (15), characterized in that: The wind turbine blade root body (15) is provided with a fiber grating array (17) in sequence. The fiber grating array (17) includes a fiber grating measuring point No. 1 (1), a fiber grating measuring point No. 2 (2), a fiber grating measuring point No. 3 (3), a fiber grating measuring point No. 4 (4), a fiber grating measuring point No. 5 (5), a fiber grating measuring point No. 6 (6) and an optical fiber jumper (16) located inside the wind turbine blade root body (15). The fiber grating measuring point No. 1 (1), the fiber grating measuring point No. 2 (2), the fiber grating measuring point No. 3 (3), the fiber grating measuring point No. 4 (4), the fiber grating measuring point No. 5 (5), the fiber grating measuring point No. 6 (6) and an optical fiber jumper (16) are provided. The measuring point (2), the third fiber Bragg grating measuring point (3), the fourth fiber Bragg grating measuring point (4), the fifth fiber Bragg grating measuring point (5) and the sixth fiber Bragg grating measuring point (6) are connected respectively by optical fiber jumpers (16), the end close to the fourth fiber Bragg grating measuring point (4) is set as the PS end connection end (7), the end close to the third fiber Bragg grating measuring point (3) is set as the demodulator connection end (8), and the end close to the first fiber Bragg grating measuring point (1) is set as the SS end connection end (9).

2. The wind turbine blade root load monitoring device according to claim 1, characterized in that: The optical fiber jumper (16) connected at only one end is connected to a pigtail (10), an optical fiber protection tube (11) is provided outside the pigtail (10), a connector (12) is fixedly connected to the side of the optical fiber protection tube (11), and a plurality of fiber-reinforced composite material bundle layers (14) and epoxy resin layers (13) are sequentially provided outside the optical fiber grating array (17).

3. The wind turbine blade root load monitoring device according to claim 1, characterized in that: The fiber gratings of the fiber grating array (17) are arranged in the axial direction of the fan blade for monitoring the axial load, the circumferential direction of the fan blade for monitoring the circumferential load, and the 45° direction for monitoring the torsional load. The central reflection wavelengths of the fiber gratings of the fiber grating array (17) are different, and the wavelength intervals between them are preferably greater than 3 nm.

4. The wind turbine blade root load monitoring device according to claim 2, characterized in that: The optical fiber protection tube (11) can be a rubber tube or a plastic tube. The diameter of the optical fiber protection tube (11) is preferably between 2 mm and 3.5 mm, and the inner diameter of the optical fiber protection tube (11) is preferably between 2 mm and 3 mm.

5. The wind turbine blade root load monitoring device according to claim 1, characterized in that: The fiber grating array (17) is composed of n single fiber gratings, where n is greater than or equal to 2. The fiber grating array (17) is directly laser-written on an optical fiber without removing the coating layer using existing technology.

6. The wind turbine blade root load monitoring device according to claim 1, characterized in that: The demodulator connection end (8) is connected to the fiber Bragg grating demodulator, and the fiber Bragg grating array (17) is connected to the wind turbine's communication system via an Ethernet cable, thereby completing data interaction with the server of the wind turbine wind turbine blade root structure monitoring system software platform at the wind farm's centralized control center.

7. The wind turbine blade root load monitoring device according to claim 6, characterized in that: The wind turbine blade root structure monitoring system software platform uses the modbus / TCP protocol and a fiber grating demodulator to read stress monitoring data and perform display, processing, storage and information alarm.

8. The wind turbine blade root load monitoring device according to claim 6, characterized in that: The wind turbine blade root structure monitoring system software platform is a B / S architecture. The wind turbine blade root structure monitoring system software is deployed on the server of the wind turbine control center and the cloud server in the cloud, both of which can be remotely accessed.

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