Hydrogen dissolved in transformer oil monitoring device, monitoring system and preparation method

Abstract

The application provides a transformer oil hydrogen dissolved monitoring device, a monitoring system and a preparation method, and belongs to the technical field of power system monitoring equipment. The monitoring device comprises a sensing probe and a control box, the sensing probe is connected with the control box, a hydrogen-sensitive sensing material layer is arranged on the sensing probe, the hydrogen-sensitive sensing material layer is a zinc oxide nanorod material layer doped with cobalt elements, and the control box is used for outputting an induction signal acquired by the sensing probe. The transformer oil hydrogen dissolved monitoring device and the monitoring system can solve the technical problems of poor real-time sensitivity and accuracy in monitoring the hydrogen concentration in transformer oil in the related art.

Description

Technical Field

[0001] This invention relates to the field of power system monitoring equipment technology, and in particular to a device, system and preparation method for monitoring dissolved hydrogen in transformer oil. Background Technology

[0002] Power transformers are among the most critical electrical devices, and their operating conditions directly impact the safety and reliability of the power system. A transformer failure can cause significant economic losses to my country's national economy; therefore, real-time monitoring of transformer operating status and ensuring their safe operation are of paramount importance.

[0003] Currently, dissolved gas detection technology in transformer oil is the most important method for transformer condition diagnosis. Dissolved hydrogen in the oil is a marker of transformer overheating. As overheating, partial discharge, and electrical sparks worsen, the dissolved hydrogen content in the oil will significantly increase. By analyzing the hydrogen concentration and its growth trend, early risk warnings can be provided. Existing transformer oil and gas analysis techniques mainly include gas chromatography, mass spectrometry, and spectroscopy.

[0004] Gas chromatography (GC) is used to separate and detect gases in transformer oil. This method features high resolution, high precision, and high sensitivity, but it suffers from poor real-time performance and requires frequent maintenance of spare parts. Mass spectrometry (MS) is used to analyze and identify gases in transformer oil. This method can efficiently separate and accurately identify gas components, but it is costly, and equipment such as sampling bottles may contaminate the samples. Spectroscopy is used for rapid detection of dissolved gases in transformer oil. This method is simple to operate, but it has limitations on the types and concentrations of gases, and its precision and sensitivity are insufficient. Furthermore, all of the above methods require oil-gas oscillation separation, which is time-consuming and cannot achieve real-time monitoring. Summary of the Invention

[0005] This invention provides a device, system, and preparation method for monitoring dissolved hydrogen in transformer oil, which solves the technical problems of poor real-time sensitivity and accuracy in related technologies for monitoring dissolved hydrogen concentration in transformer oil. The technical solution is as follows:

[0006] In a first aspect, embodiments of the present invention provide a device for monitoring dissolved hydrogen in transformer oil, comprising: a sensing probe and a control box.

[0007] The sensing probe is connected to the control box. A hydrogen-sensitive sensing material layer is disposed on the sensing probe. The hydrogen-sensitive sensing material layer is a zinc oxide nanorod material layer doped with cobalt. The control box is used to output the sensing signal acquired by the sensing probe.

[0008] Optionally, the hydrogen-sensitive sensing material layer includes a zinc oxide material layer and a zeolite imidazole ester framework structure material layer covering the zinc oxide material layer.

[0009] Optionally, the transformer oil dissolved hydrogen monitoring device further includes a cylindrical permeation membrane, which is disposed outside the sensing probe.

[0010] Optionally, the transformer oil dissolved hydrogen monitoring device further includes a permeate membrane support, which is arranged around the sensing probe, and the cylindrical permeate membrane is sleeved on the permeate membrane support.

[0011] Optionally, the permeation membrane support is cylindrical, and multiple permeation openings are uniformly arranged in a circumferential array on the sidewall of the permeation membrane support.

[0012] Optionally, the cylindrical permeation membrane is a polytetrafluoroethylene, fluorinated polymer, or polyvinylidene fluoride membrane.

[0013] Secondly, embodiments of the present invention provide a monitoring system, including the dissolved hydrogen monitoring device in transformer oil described in the first aspect, and further including an oil-immersed transformer tank, wherein the control box is disposed outside the oil-immersed transformer tank, and the sensing probe extends into and is disposed inside the oil-immersed transformer tank.

[0014] Thirdly, the present invention provides a preparation method applicable to the transformer oil dissolved hydrogen monitoring device described in the first aspect above. The preparation method includes: slowly adding a 0.03 mol / L sodium hydroxide methanol solution to a 0.01 mol / L zinc acetate methanol solution and stirring at 60°C for 2 hours to obtain a zinc oxide nanocrystal dispersion. Then, the zinc oxide nanocrystals are spin-coated three times onto a ceramic substrate printed with electrodes and dried to form a seed layer.

[0015] A ceramic substrate coated with a zinc oxide seed layer was placed in an aqueous solution of zinc nitrate hexahydrate and hexamethylenetetramine of equal concentration, and heated at 80°C for 6 hours to carry out a hydrothermal reaction, thereby growing a zinc oxide nanorod array on the ceramic substrate.

[0016] The prepared zinc oxide nanorod array was immersed in a mixture containing 0.1 g of 45-dichloroimidazole, 16 mL of dimethylformamide, and distilled water, wherein the volume ratio of dimethylformamide to distilled water was 3:1. Approximately 0.05 g of cobalt nitrate hexahydrate was added during the solvothermal reaction. The entire assembly was then transferred to a stainless steel reactor with a tetrafluoroethylene liner. The reactor was heated at 70 °C for 2 hours. Finally, the assembly was washed with ethanol and dried at 60 °C to obtain the cobalt-doped zinc oxide nanorod material layer.

[0017] The beneficial effects of the technical solutions provided in the embodiments of the present invention include at least the following:

[0018] The transformer oil dissolved hydrogen monitoring device provided in this invention utilizes zinc oxide nanorods in the hydrogen-sensitive sensing material layer on its sensing probe. These nanorods have a small grain size and a large specific surface area, which improves the sensitivity to hydrogen. Furthermore, the addition of a specific proportion of cobalt to the zinc oxide increases the number of oxygen vacancies and active sites on the zinc oxide surface, accelerating the adsorption-desorption process of gas molecules and lowering the contact barrier height. This allows for rapid response to hydrogen in the transformer oil, with high sensitivity and response value. When a transformer malfunctions, the device detects the rapidly increasing hydrogen content in the oil and outputs a sensing signal through the control box, providing both an early warning and the hydrogen concentration and growth rate, facilitating timely countermeasures by staff. This invention solves the technical problems of poor real-time sensitivity and accuracy in related technologies for monitoring dissolved hydrogen concentration in transformer oil. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a three-dimensional structural schematic diagram of the hydrogen dissolved in transformer oil monitoring device provided in an embodiment of the present invention;

[0021] Figure 2 This is a schematic diagram of the structure of the cylindrical permeation membrane provided in an embodiment of the present invention;

[0022] Figure 3 This is a cross-sectional view of the assembly structure of the hydrogen dissolved in transformer oil monitoring device provided in an embodiment of the present invention;

[0023] Figure 4 This is a TEM image of the hydrogen-sensitive sensing material layer magnified to 1 μm provided in the embodiments of the present invention;

[0024] Figure 5 This is a TEM image of the hydrogen-sensitive sensing material layer magnified to 100 nm provided in the embodiments of the present invention;

[0025] Figure 6 This is a TEM image of the hydrogen-sensitive sensing material layer magnified to 20 nm provided in the embodiments of the present invention;

[0026] Figure 7This is a schematic diagram of the detection system provided in an embodiment of the present invention;

[0027] Figure 8 The flowchart of a preparation method provided in an embodiment of the present invention is shown.

[0028] In the picture:

[0029] 1-Sensing probe; 2-Control box; 3-Cylindrical permeation membrane; 4-Permeation membrane support; 5-Oil-immersed transformer tank; 11-Hydrogen-sensitive sensing material layer; 11a-Zinc oxide material layer; 11b-Zeol imidazolium ester skeleton structure material layer; 41-Permeation opening. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below with reference to the accompanying drawings.

[0031] Currently, dissolved gas detection technology in transformer oil is the most important method for transformer condition diagnosis. Dissolved hydrogen in the oil is a marker of transformer overheating. As overheating, partial discharge, and electrical sparks worsen, the dissolved hydrogen content in the oil will significantly increase. By analyzing the hydrogen concentration and its growth trend, early risk warnings can be provided. Existing transformer oil and gas analysis techniques mainly include gas chromatography, mass spectrometry, and spectroscopy.

[0032] Gas chromatography (GC) is used to separate and detect gases in transformer oil. This method features high resolution, high precision, and high sensitivity, but it suffers from poor real-time performance and requires frequent maintenance of spare parts. Mass spectrometry (MS) is used to analyze and identify gases in transformer oil. This method can efficiently separate and accurately identify gas components, but it is costly, and equipment such as sampling bottles may contaminate the samples. Spectroscopy is used for rapid detection of dissolved gases in transformer oil. This method is simple to operate, but it has limitations on the types and concentrations of gases, and its precision and sensitivity are insufficient. Furthermore, all of the above methods require oil-gas oscillation separation, which is time-consuming and cannot achieve real-time monitoring.

[0033] Figure 1 This is a three-dimensional structural schematic diagram of the hydrogen dissolved in transformer oil monitoring device provided in an embodiment of the present invention. Figure 2 This is a schematic diagram of the structure of the cylindrical permeation membrane provided in an embodiment of the present invention. Figure 3 This is a cross-sectional view of the assembly structure of the hydrogen dissolved in transformer oil monitoring device provided in an embodiment of the present invention. Figure 4 This is a TEM image of the hydrogen-sensitive sensing material layer magnified to 1 μm provided in an embodiment of the present invention. Figure 5 This is a TEM image of the hydrogen-sensitive sensing material layer magnified to 100 nm provided in the embodiments of the present invention. Figure 6This is a magnified TEM image of the hydrogen-sensitive sensing material layer provided in this embodiment of the invention, magnified to 20 nm. Figures 1 to 6 As shown, through practice, this embodiment of the invention provides a device for monitoring dissolved hydrogen in transformer oil, including a sensing probe 1 and a control box 2.

[0034] The sensing probe 1 is connected to the control box 2. The sensing probe 1 is provided with a hydrogen-sensitive sensing material layer 11, which is a zinc oxide nanorod material layer doped with cobalt. The control box 2 is used to output the sensing signal acquired by the sensing probe 1.

[0035] In this embodiment of the invention, the hydrogen dissolved in transformer oil monitoring device is suitable for oil-immersed transformers. Its control box 2 is installed on the oil tank 5 of the oil-immersed transformer, while the sensing probe 1 extends into and is positioned inside the oil tank 5, contacting the transformer oil. The sensing probe 1 is provided with a hydrogen-sensitive sensing material layer 11, which reacts with the hydrogen atoms contained in the transformer oil, causing a change in surface potential. This, in turn, causes a change in the resistance or capacitance inside the sensing probe 1, which is converted into an electrical signal by a corresponding circuit. This signal is then output through the circuitry in the control box 2, analyzed in the background by an external host computer, and finally converted into a concentration output for visualization.

[0036] The hydrogen-sensitive sensing material layer 11 is a zinc oxide nanorod-shaped material layer doped with cobalt. Its structure can be visualized as a zinc oxide material layer 11a and a zeolite imidazole ester framework structure material layer 11b coating the zinc oxide material layer 11a. The preparation method mainly includes the following steps:

[0037] A 0.03 mol / L sodium hydroxide methanol solution was slowly added to a 0.01 mol / L zinc acetate methanol solution, and the mixture was stirred at 60 °C for 2 hours to obtain a zinc oxide nanocrystal dispersion. The zinc oxide nanocrystals were then spin-coated three times onto a ceramic substrate with printed electrodes and dried to form a seed layer.

[0038] Subsequently, a ceramic substrate coated with a zinc oxide seed layer was placed in an aqueous solution of zinc nitrate hexahydrate and hexamethylenetetramine of equal concentration and heated at 80°C for 6 hours to carry out a hydrothermal reaction, so as to grow an array of zinc oxide nanorods on the ceramic substrate.

[0039] Subsequently, the prepared zinc oxide nanorod array was immersed in a mixture containing 0.1 g of 45-dichloroimidazole, 16 mL of dimethylformamide, and distilled water, wherein the volume ratio of dimethylformamide to distilled water was 3:1. Approximately 0.05 g of cobalt nitrate hexahydrate was added during the solvothermal reaction. The entire assembly was then transferred to a stainless steel reactor with a tetrafluoroethylene liner. The reactor was heated at 70 °C for 2 hours. Finally, the assembly was washed with ethanol and dried at 60 °C to obtain a zinc oxide nanorod material layer doped with cobalt.

[0040] By strictly controlling the dosage of the drugs in each step according to the calibration, it is beneficial to form a specific porous nanofiber structure, so that the final prepared zinc oxide nanorod material layer doped with cobalt has a large specific surface area and higher gas sensitivity.

[0041] The transformer oil dissolved hydrogen monitoring device provided in this embodiment of the invention utilizes zinc oxide nanorod-shaped material in the hydrogen-sensitive sensing material layer 11 on its sensing probe 1. This material has a nanorod-shaped structure, small grain size, and large specific surface area, which improves the sensitivity to hydrogen. Furthermore, the addition of a specific proportion of cobalt to the zinc oxide increases the number of oxygen vacancies and active sites on the zinc oxide surface, accelerating the surface adsorption-desorption process of gas molecules and reducing the contact barrier height. This allows for rapid response to hydrogen in the transformer oil, with high sensitivity and response value. When a transformer malfunctions, the device detects the rapidly increasing hydrogen content in the oil and outputs a sensing signal through the control box 2, providing both an early warning and the hydrogen concentration value and growth rate, facilitating timely response by staff. This invention solves the technical problems of poor real-time sensitivity and accuracy in related technologies for monitoring dissolved hydrogen concentration in transformer oil.

[0042] Optionally, the transformer oil dissolved hydrogen monitoring device further includes a cylindrical permeable membrane 3, which is disposed outside the sensing probe 1. Exemplarily, in this embodiment of the invention, by fixing a cylindrical permeable membrane 3 to the outside of the sensing probe 1, which extends into the oil-immersed transformer tank 5, and ensuring that the membrane 3 is completely immersed in the transformer oil, the gas-liquid two-phase interaction area is greatly increased. Dissolved hydrogen in the oil, through thermal motion and diffusion, fully permeates into the cylindrical structure, quickly reaching dynamic equilibrium and contacting the sensing probe 1. Furthermore, the cylindrical permeable membrane 3 can also isolate and filter impurities in the oil, preventing impurities from contacting the sensing probe 1 and causing scaling and sensing failure, effectively improving the monitoring and response accuracy of the transformer oil dissolved hydrogen monitoring device.

[0043] Optionally, the transformer oil dissolved hydrogen monitoring device further includes a permeate membrane support 4, which is arranged around the sensing probe 1, and a cylindrical permeate membrane 3 is fitted onto the permeate membrane support 4. Exemplarily, in this embodiment of the invention, the cylindrical permeate membrane 3 is shaped and supported by the additional permeate membrane support 4. The permeate membrane support 4 is cylindrical, and multiple permeation openings 41 are uniformly arranged in a circumferential array on its sidewall. The opening at the end of the permeate membrane support 4 away from the inner wall of the oil-immersed transformer tank 5, and the permeation openings 41 on the sidewall, ensure oil permeation and the gas-liquid two-phase interaction area. This avoids problems such as deformation and damage to the cylindrical permeate membrane 3 due to oil pressure changes caused by oil temperature variations, further improving the overall service life of the transformer oil dissolved hydrogen monitoring device.

[0044] Optionally, the cylindrical permeate membrane 3 is made of polytetrafluoroethylene (PTFE), fluorinated polymers, or polyvinylidene fluoride (PVDF). Exemplarily, in this embodiment of the invention, the cylindrical permeate membrane 3 is made of fluorinated polymer-based permeate membranes, such as polytetrafluoroethylene (PTFE), fluorinated polymers (FEP), and polyvinylidene fluoride (PVDF), which possess extremely high hydrogen permeability and selectivity. A suitable cylindrical permeate membrane is prepared using methods such as membrane processing, dip coating, spraying, electrochemical polymerization, or nanomaterial electrophoretic deposition, ensuring that the inner diameter can completely accommodate the sensing probe 1. During assembly, the sensing probe 1 is bridged and fixed at the center of the cylindrical permeate membrane 3, and its position is adjusted to ensure an appropriate distance between the sensing probe 1 and the surface of the cylindrical permeate membrane 3. The shape of the cylindrical membrane is then cured, and a layer of anti-corrosion agent is coated on the surface of the encapsulated cylindrical permeate membrane 3 to protect the quality of the permeate membrane and ensure long-term stable use. Finally, it is checked whether the sensing probe 1 has achieved encapsulation, protection, and safeguarding, and whether the minimum detection range of the sensing probe 1 meets the usage requirements, completing the overall assembly of the transformer oil dissolved hydrogen monitoring device.

[0045] Figure 7 This is a schematic diagram of the structure of a monitoring system provided in an embodiment of the present invention. Figure 7 As shown, embodiments of the present invention also provide a monitoring system, including as follows: Figures 1 to 6 The transformer oil dissolved hydrogen monitoring device shown is characterized in that it further includes an oil-immersed transformer oil tank 5, a control box 2 is disposed outside the oil-immersed transformer oil tank 5, and a sensing probe 1 extends into and is disposed inside the oil-immersed transformer oil tank 5.

[0046] The hydrogen dissolved in transformer oil monitoring device provided in this embodiment of the invention is assembled with an oil-immersed transformer tank 5 to form a monitoring system. The hydrogen-sensitive sensing material layer 11 on the sensing probe 1 uses zinc oxide nanorod-shaped material with a nanorod structure, small grain size, and large specific surface area, which is beneficial for improving the sensitivity to hydrogen. Combined with the addition of a specific proportion of cobalt to the zinc oxide, the number of oxygen vacancies and active sites on the zinc oxide surface increases accordingly, accelerating the surface adsorption-desorption process of gas molecules, reducing the contact barrier height, and enabling rapid response to hydrogen contained in the transformer oil with high sensitivity and response value. When a transformer fault occurs, by detecting the rapidly increasing hydrogen content in the oil, the control box 2 outputs a sensing signal, issuing an early warning while providing the hydrogen concentration value and growth rate, facilitating timely response by personnel. This solves the technical problems of poor real-time sensitivity and accuracy in related technologies for monitoring the dissolved hydrogen concentration in transformer oil.

[0047] Figure 8 This is a flowchart of a preparation method provided in an embodiment of the present invention. For example... Figure 8 As shown, embodiments of the present invention also provide a preparation method suitable for applications such as 1 to Figure 6 The transformer oil dissolved hydrogen monitoring device described herein. The preparation method includes:

[0048] S1. A 0.03 mol / L sodium hydroxide methanol solution is slowly added to a 0.01 mol / L zinc acetate methanol solution and stirred at 60°C for 2 hours to obtain a zinc oxide nanocrystal dispersion. Then, the zinc oxide nanocrystals are spin-coated three times onto a ceramic substrate with printed electrodes and dried to form a seed layer.

[0049] S2. A ceramic substrate coated with a zinc oxide seed layer is placed in an aqueous solution of zinc nitrate hexahydrate and hexamethylenetetramine of equal concentration and heated at 80°C for 6 hours to carry out a hydrothermal reaction in order to grow a zinc oxide nanorod array on the ceramic substrate.

[0050] S3. The prepared zinc oxide nanorod array was immersed in a mixture containing 0.1 g of 45-dichloroimidazole, 16 mL of dimethylformamide and distilled water, wherein the volume ratio of dimethylformamide to distilled water was 3:1. Approximately 0.05 g of cobalt nitrate hexahydrate was added during the solvothermal reaction. The entire assembly was then transferred to a stainless steel reactor with a tetrafluoroethylene liner. The reactor was heated at 70 °C for 2 hours. Finally, the assembly was washed with ethanol and dried at 60 °C to obtain a zinc oxide nanorod material layer doped with cobalt.

[0051] By strictly controlling the dosage of reagents in each step according to calibration, a specific porous nanofiber structure can be formed, resulting in a cobalt-doped zinc oxide nanorod material layer with a large specific surface area and higher gas sensitivity. The above preparation method is simple and inexpensive, but this preparation form is not the final packaging form; it mainly facilitates material performance testing. The MEMS (Micro-Electro-Mechanical Systems) packaging form of the magnetron sputtering method mentioned below is more conducive to large-scale industrial production.

[0052] After preparing the hydrogen-sensitive sensing material layer 11 using the above method, a clean, defect-free silicon wafer of suitable size is selected and cut into a substrate required for MEMS fabrication. Photolithography is used to precisely transfer the shape, position, and spacing of the MEMS device structure onto the silicon wafer surface. Chemical vapor deposition (CVD) is used to successively prepare support films, platinum heating bands, isolation films, and interdigitated metal electrodes on the silicon wafer surface. Dry etching is used to remove unwanted silicon material. Finally, the MEMS chip is obtained by offline water washing. A target material is fabricated using cobalt-doped zinc oxide nanorods via magnetron sputtering. Inert gases such as argon are added to a vacuum chamber, and an excitation magnetic field is generated by passing an electric current. A particle beam bombards the target material, causing it to peel off and sputter onto the chip surface, forming a deposition layer. Micro-nano fabrication processes are used to organically combine the deposition layer with the MEMS chip and micro-fabricate the microelectronic materials to form a MEMS sensor, which is the sensing probe 1 provided in this embodiment of the invention.

[0053] The sensor probe 1 exhibits high sensitivity and selectivity in detecting hydrogen leakage from transformers. When a transformer malfunctions, it detects a rapid increase in hydrogen content in the oil, issuing an early warning and providing the hydrogen concentration and growth rate, facilitating timely response by staff and reducing the risk of accidents. The sensor probe 1 utilizes nano-metal oxides as the sensing material, resulting in excellent time stability and ensuring accurate long-term monitoring of hydrogen.

[0054] Unless otherwise defined, the technical or scientific terms used herein shall have the ordinary meaning as understood by one of ordinary skill in the art to which this invention pertains. The terms “first,” “second,” and similar terms used in this patent application specification and claims do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an” or “a” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “comprising” or “including” and similar terms mean that the elements or objects preceding “comprising” or “including” encompass the elements or objects listed following “comprising” or “including” and their equivalents, and do not exclude other elements or objects. The terms “connected” or “linked” and similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” and “right” are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0055] The above description is merely an optional embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A device for monitoring dissolved hydrogen in transformer oil, characterized in that, include: Sensor probe (1) and control box (2). The sensing probe (1) is connected to the control box (2). A hydrogen-sensitive sensing material layer (11) is provided on the sensing probe (1). The hydrogen-sensitive sensing material layer (11) is a zinc oxide nanorod material layer doped with cobalt. The control box (2) is used to output the sensing signal acquired by the sensing probe (1). The transformer oil dissolved hydrogen monitoring device also includes a columnar permeation membrane (3), which is covered outside the sensing probe (1); The transformer oil hydrogen dissolution monitoring device also includes a permeation membrane support (4), which is arranged around the sensing probe (1). The cylindrical permeation membrane (3) is sleeved on the permeation membrane support (4). The permeation membrane support (4) is cylindrical, and multiple permeation openings (41) are uniformly arranged in a circumferential array on the side wall of the permeation membrane support (4).

2. The hydrogen-sensitive sensing material layer (11) includes a zinc oxide material layer (11a) and a zeolite imidazole ester framework structure material layer (11b) covering the outside of the zinc oxide material layer (11a).

3. The transformer oil dissolved hydrogen monitoring device of claim 1, wherein, The columnar permeation membrane (3) is a polytetrafluoroethylene, fluorinated polymer, or polyvinylidene fluoride membrane.

4. A monitoring system comprising the transformer oil dissolved hydrogen monitoring device according to any one of claims 1 to 3, characterized in that, It also includes an oil-immersed transformer tank (5), the control box (2) is located outside the oil-immersed transformer tank (5), and the sensing probe (1) extends into and is located inside the oil-immersed transformer tank (5).

5. A preparation method applicable to the transformer oil dissolved hydrogen monitoring device as described in any one of claims 1 to 3, characterized in that, The preparation method includes: A 0.03 mol / L sodium hydroxide methanol solution was slowly added to a 0.01 mol / L zinc acetate methanol solution, and stirred at 60 °C for 2 hours to obtain a zinc oxide nanocrystal dispersion. The zinc oxide nanocrystals were then spin-coated three times onto a ceramic substrate with printed electrodes and dried to form a seed layer. A ceramic substrate coated with a zinc oxide seed layer was placed in an aqueous solution of zinc nitrate hexahydrate and hexamethylenetetramine of equal concentration and heated at 80 °C for 6 hours to carry out a hydrothermal reaction, so as to grow a zinc oxide nanorod array on the ceramic substrate. The prepared zinc oxide nanorod array was immersed in a mixture containing 0.1 g of 45-dichloroimidazole, 16 mL of dimethylformamide, and distilled water, wherein the volume ratio of dimethylformamide to distilled water was 3:

1. Approximately 0.05 g of cobalt nitrate hexahydrate was added during the solvothermal reaction. The entire assembly was then transferred to a stainless steel reactor with a tetrafluoroethylene liner. The reactor was heated at 70°C for 2 hours. Finally, the assembly was washed with ethanol and dried at 60°C to obtain the cobalt-doped zinc oxide nanorod material layer.

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