Device for sensing hydrogen dissolved in oil based on V-shaped cut optical fiber FBG (Fiber Bragg Grating)

Abstract

The invention relates to a device for sensing hydrogen dissolved in oil based on a V-shaped cut optical fiber FBG (Fiber Bragg Grating), which is suitable for the fields of optical fiber sensing, power system state monitoring and the like and comprises two key technologies, namely a sensor cutting manufacturing technology and a sensor film coating technology. The invention provides a device for sensing hydrogen dissolved in oil based on a V-shaped cut FBG (Fiber Bragg Grating), which realizes the detection of hydrogen dissolved in transformer oil by performing V-shaped cutting sensitization on the surface of the FBG and sputtering an expandable palladium alloy capable of specifically absorbing hydrogen. The coverage area of the palladium alloy film is increased through the V-shaped cutting structure, the sensitivity is improved, the binding power of the film is improved by changing the metal component proportion of the palladium alloy, and the repeated measurement strength of the film is improved by improving the microstructure of the film. The device can be directly arranged in the transformer to measure hydrogen dissolved in oil.

Description

Technical Field

[0001] The invention relates to a dissolved hydrogen in oil sensing device based on a V-cut optical fiber FBG, which is suitable for the fields of optical fiber sensing, power system status monitoring, etc. Background Art

[0002] As the operation hub equipment of power transmission and distribution in power system, transformer is one of the most important components of power system. Once a fault occurs, it will bring great threat to the stable operation of power system and social production. Therefore, the safe and stable operation of transformer is of far-reaching significance for ensuring the safety of power grid. Traditional transformer status monitoring methods mainly rely on electrical sensors and electronic equipment, which may be affected by electromagnetic interference and may have reliability problems during long-term operation. Fiber optic sensing technology has gradually become an important means of transformer status monitoring due to its advantages of anti-electromagnetic interference, high reliability and ability to realize distributed measurement. For the measurement of dissolved hydrogen in transformer oil, the current detection methods are mainly concentrated on dissolved gas analysis (DGA), which requires taking transformer oil samples, degassing them, and analyzing the components of the generated gas. The detection time is long and it is difficult to reflect the abnormal situation in the transformer in time.

[0003] Dissolved Gas Analysis (DGA) is a technology used to diagnose internal faults in transformers and other electrical equipment. DGA helps identify potential problems with equipment by analyzing the gas components dissolved in insulating oil. During the operation of power equipment (especially transformers), internal faults often lead to high temperatures or arc discharges. These abnormal conditions can cause changes in the dissolved gases in the oil. Therefore, by monitoring the type and concentration of these gases, equipment failures can be predicted in advance and preventive maintenance can be performed.

[0004] Transformer gas protection technology (Gas-Relay Protection) is a protection technology based on the change of gas concentration in the transformer oil tank, which is widely used in the protection and monitoring of transformers in power systems. Gas protection technology mainly detects the gas in the oil inside the transformer, especially the type and concentration change of the gas, to determine whether the transformer has internal faults, such as partial discharge, overheating, short circuit, etc. Gas protection is a very effective means of early fault diagnosis. It can detect potential problems of the transformer in time, thereby avoiding serious accidents.

[0005] For the dissolved gas analysis technology (DGA), it is necessary to take transformer oil samples from the oil tapping port, degas them, and analyze the components of the generated gas. The detection time is long, and it is difficult to quickly and timely respond to abnormal conditions in the transformer. In addition, it is impossible to monitor the specific location of the fault.

[0006] For gas protection, since gas protection relies on gas accumulation, the alarm may be triggered only in very serious fault conditions, with a certain delay. And in some cases, changes in gas concentration may be caused by external factors (such as changes in ambient temperature) rather than internal faults, which may lead to false alarms.

[0007] In order to solve the above problems, the present invention proposes a dissolved hydrogen in oil sensing device based on V-cut optical fiber FBG, which uses V-cutting on the surface of fiber Bragg grating (FBG) to enhance sensitivity and sputter palladium alloy that specifically absorbs hydrogen and can expand, so as to detect dissolved hydrogen in transformer oil. The V-cut structure is used to increase the coverage area of ​​the palladium alloy film to improve the sensitivity, and the ratio of the metal components of the palladium alloy is changed to improve the adhesion of the film and improve the microstructure of the film to improve the repeated measurement strength of the film. It can be directly built into the transformer to measure dissolved hydrogen in oil. Summary of the invention

[0008] The present invention proposes a dissolved hydrogen in oil sensor device based on V-cut optical fiber FBG, which includes two key technologies: sensor cutting and sensor coating technology.

[0009] Figure 1 A schematic cross-sectional view of a dissolved hydrogen in oil sensing device based on a V-cut optical fiber FBG provided by the present invention; Figure 2 A schematic diagram of the cross-sectional coating of a dissolved hydrogen in oil sensing device based on a V-cut optical fiber FBG provided by the present invention.

[0010] The V-cutting method of the fiber Bragg grating (FBG) is as follows: the cross-section of the grating area of ​​the fiber Bragg grating (FBG) is circular, and lines are drawn upward from the center O and the diameters A and B parallel to the plane, where ∠ACB and ∠DOE are 90°, AC=AB, AC and OD intersect at point M, BC and OE intersect at point N, and ∠CMN and ∠CNM are both 45°.

[0011] The V-cutting process of the fiber Bragg grating (FBG) is as follows: first, the grating area is polished into a triangle along AC and BC by side polishing, and then the discontinuity of the triangle is cut off to form the MN plane, and finally the area to be coated with AMNB as the surface is formed. Cutting in this way is conducive to improving the bonding force of the coating, and at the same time, the grating area can fully contact with the film, thereby improving the sensitivity.

[0012] The palladium alloy film composition of the fiber Bragg grating (FBG) is selected as follows: palladium (Pd) has a specific absorption effect on hydrogen, and it will expand when absorbing hydrogen. Acting on the grating area of ​​FBG can change the interference wavelength of the optical signal, and then measure the hydrogen concentration. Gold (Au) can enhance the corrosion resistance and stability of palladium, and can form a lattice with palladium at the atomic level to increase the speed of palladium absorbing hydrogen. Nickel (Ni) and titanium (Ti) can be used to make memory alloys to improve the repeatability of palladium absorbing and releasing hydrogen. The content ratio of each metal is palladium: gold: nickel: titanium = 73%: 22%: 2%: 3%.

[0013] The palladium alloy film coating method of the fiber Bragg grating (FBG) is as follows: four alloys are sputtered proportionally onto the surface of the cut FBG grating area by magnetron sputtering, and the sputtering thickness is 5 μm. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a schematic cross-sectional cutting diagram of a dissolved hydrogen in oil sensing device based on V-cut optical fiber FBG.

[0015] Figure 2 This is a schematic diagram of the cross-sectional coating of a dissolved hydrogen in oil sensing device based on a V-cut optical fiber FBG. Specific implementation plan The embodiments are described in detail below in conjunction with the accompanying drawings.

[0016] In order to more clearly explain the objectives, technical solutions and advantages of this patent application, the following content will describe this application in detail with reference to the accompanying drawings and examples. It should be noted that the embodiments described herein are only used to explain the contents of this application and do not constitute any limitation to this application. Any other implementation methods obtained by any person skilled in the art according to this application without performing creative work shall be deemed as the scope of protection covered by this application.

[0017] The drawings mentioned in the patent only show some examples or implementations of the present patent application. For those of ordinary skill in the art, they can apply the principles of the present application to other similar situations based on these drawings without performing creative work. At the same time, it should also be recognized that although complex efforts may be required during the development process, for those of ordinary skill in the art, the adjustments and changes in design, manufacturing or production based on the technical content disclosed in the present application are merely routine technical operations and should not be regarded as incompleteness of the disclosure of the present application.

[0018] Figure 1 A schematic cross-sectional view of a dissolved hydrogen in oil sensing device based on a V-cut optical fiber FBG provided by the present invention; Figure 2A schematic diagram of the cross-sectional coating of a dissolved hydrogen in oil sensing device based on a V-cut optical fiber FBG provided by the present invention.

[0019] Example 1: Figure 1 The figure shows a cross-sectional cutting schematic diagram of a dissolved hydrogen in oil sensor device based on a V-cut optical fiber FBG, and provides a cutting method of the present invention. The cross section of the fiber Bragg grating (FBG) is circular, and lines are drawn upward from the center O and the diameters A and B parallel to the plane, where ∠ACB and ∠DOE are 90°, AC=AB, AC and OD intersect at point M, BC and OE intersect at point N, and ∠CMN and ∠CNM are both 45°.

[0020] The V-cutting process of the fiber Bragg grating (FBG) is as follows: first, the grating area is polished into a triangle along AC and BC by side polishing, and then the discontinuity of the triangle is cut off to form the MN plane, and finally the area to be coated with AMNB as the surface is formed. Cutting in this way is conducive to improving the bonding force of the coating, and at the same time, the grating area can fully contact with the film, thereby improving the sensitivity.

[0021] Example 2: Figure 2 The figure shows a cross-sectional coating schematic diagram of a dissolved hydrogen in oil sensor device based on a V-cut optical fiber FBG, which provides the coating method and film component selection of the present invention. The palladium alloy film component of the fiber Bragg grating (FBG) is selected as follows: palladium (Pd) has a specific absorption effect on hydrogen, and it will expand when absorbing hydrogen. Acting on the grating area of ​​FBG can change the interference wavelength of the optical signal, and then measure the hydrogen concentration. Gold (Au) can enhance the corrosion resistance and stability of palladium, and can form a lattice with palladium at the atomic level to increase the speed of palladium hydrogen absorption. Nickel (Ni) and titanium (Ti) can be used to make memory alloys to improve the repeatability of palladium hydrogen absorption and release. The content ratio of each metal is palladium: gold: nickel: titanium = 73%: 22%: 2%: 3%.

[0022] The palladium alloy film coating method of the fiber Bragg grating (FBG) is as follows: four alloys are sputtered proportionally onto the surface of the cut FBG grating area by magnetron sputtering, and the sputtering thickness is 5 μm.

Claims

1. The present invention proposes a dissolved hydrogen in oil sensor device based on V-cut optical fiber FBG, which includes two key technologies: sensor cutting and sensor coating technology.

2. According to claim 1, a cross-section cutting method for manufacturing a dissolved hydrogen in oil sensor device based on a V-cut optical fiber FBG, characterized in that: The V-cutting method of the fiber Bragg grating (FBG) is as follows: the cross-section of the grating area of ​​the fiber Bragg grating (FBG) is circular, and lines are drawn upward from the center O and the diameters A and B parallel to the plane, where ∠ACB and ∠DOE are 90°, AC=AB, AC and OD intersect at point M, BC and OE intersect at point N, and ∠CMN and ∠CNM are both 45°.

3. The cross-section cutting manufacturing process of the oil-dissolved hydrogen gas sensor device based on V-cut optical fiber FBG according to claim 1 is characterized in that: The V-cutting process of the fiber Bragg grating (FBG) is as follows: first, the grating area is polished into a triangle along AC and BC by side polishing, and then the discontinuity of the triangle is cut off to form the MN plane, and finally the coating area with AMNB as the surface is formed.

4. The cross-section cutting manufacturing process of the oil-dissolved hydrogen gas sensor device based on V-cut optical fiber FBG according to claim 1 is characterized in that: Cutting in this way is beneficial to improving the bonding strength of the coating, while enabling the gate area to fully contact the film, thereby improving sensitivity.

5. The film composition selection of the cross-section coating technology of the dissolved hydrogen in oil sensor device based on V-cut optical fiber FBG according to claim 1 is characterized in that: The palladium alloy film composition of the fiber Bragg grating (FBG) is selected as follows: palladium (Pd) has a specific absorption effect on hydrogen, and it will expand when absorbing hydrogen. Acting on the grating area of ​​FBG can change the interference wavelength of the optical signal, thereby measuring the hydrogen concentration.

6. The film composition selection of the cross-section coating technology of the dissolved hydrogen in oil sensor device based on V-cut optical fiber FBG according to claim 1 is characterized in that: Adding gold (Au) can enhance the corrosion resistance and stability of palladium, form a lattice with palladium at the atomic level, and increase the rate at which palladium absorbs hydrogen.

7. The film composition selection of the cross-section coating technology of the dissolved hydrogen in oil sensor device based on V-cut optical fiber FBG according to claim 1 is characterized in that: Adding nickel (Ni) and titanium (Ti) can be used to make memory alloys to improve the repeatability of palladium's hydrogen absorption and release.

8. The film composition selection of the cross-section coating technology of the dissolved hydrogen in oil sensor device based on V-cut optical fiber FBG according to claim 1 is characterized in that: The content ratio of each metal is palladium: gold: nickel: titanium = 73%: 22%: 2%: 3%.

9. The film composition selection of the cross-section coating technology of the dissolved hydrogen in oil sensor device based on V-cut optical fiber FBG according to claim 1 is characterized in that: The palladium alloy film coating method of the fiber Bragg grating (FBG) is as follows: four alloys are sputtered proportionally onto the surface of the cut FBG grating area using magnetron sputtering technology, and the sputtering thickness is 5 μm.

10. The dissolved hydrogen in oil sensing device based on V-cut optical fiber FBG according to claim 1 can be used to measure the dissolved hydrogen content in transformer oil.

Images