Device and method for measuring micro water in transformer oil

Abstract

The invention relates to a transformer oil micro-water measuring device and method, the device comprises a darkroom, a transparent oil tank is arranged in the darkroom, a laser emitter and a camera device are arranged outside the oil tank, and the laser emitting direction of the laser emitter is perpendicular to the shooting direction of the camera device; and a weak ultrasonic stirrer is also arranged in the darkroom and is used for slightly oscillating and stirring the transformer oil in the oil tank, so that micro water contained in the transformer oil is uniformly distributed. The method comprises the following steps: S1, adding to-be-detected transformer oil into an oil tank to a set height, and closing a darkroom; s2, starting a weak ultrasonic stirrer; s3, a laser emitter is started, the laser emitter emits a laser beam to the oil groove, and the laser beam penetrates through the oil groove and the transformer oil in the oil groove; s4, shooting an image of the scattered light column in the transformer oil through a camera device; and S5, performing image analysis on the image shot by the camera device through the computer to obtain the moisture content in the transformer oil. The device and the method are beneficial to improving the accuracy of measuring the micro-water in the transformer oil.

Description

Technical Field

[0001] The invention relates to the technical field of transformer oil detection, and in particular to a transformer oil micro-water measuring device and method. Background Art

[0002] The insulation performance of power transformer insulating oil is crucial to the operation of the transformer. Transformer oil usually uses indicators such as micro-water, color spectrum, and dielectric loss factor to measure the operating status of the oil, among which micro-water is one of the important indicators to characterize the moisture and oxidation of transformer oil.

[0003] The prior art usually adopts the GB / T 7600-2014 method for determining the moisture content of transformer oil and turbine oil in operation (coulometric method) for detection. When detecting according to the above method, Karl Fischer electrolyte and pure water are required as reagents. The electrolyte needs to be titrated and then shaken during the measurement process. The operation process is relatively cumbersome, and if the operation is improper, it is easy to cause large detection errors. Summary of the invention

[0004] The object of the present invention is to provide a transformer oil micro-water measurement device and method, which are conducive to improving the accuracy of transformer oil micro-water measurement.

[0005] In order to achieve the above-mentioned purpose, the technical scheme adopted by the present invention is: a transformer oil micro-water measuring device, comprising a darkroom, wherein a transparent oil tank is arranged in the darkroom, a laser transmitter and a camera device are arranged outside the oil tank, and the laser emission direction of the laser transmitter is perpendicular to the shooting direction of the camera device; a weak ultrasonic stirrer is also arranged in the darkroom, which is used to slightly oscillate and stir the transformer oil in the oil tank to promote uniform distribution of the micro-water contained in the transformer oil.

[0006] Furthermore, a support table is provided in the darkroom, and the oil tank is placed on the support table; a heating pad is provided between the upper surface of the support table and the lower bottom surface of the oil tank; a temperature measuring probe is provided in the oil tank; the laser emitter, camera device, heating pad and temperature measuring probe are all electrically connected to a computer.

[0007] Furthermore, the laser emitter and the camera device are horizontally arranged at different positions outside the oil tank, and the installation heights of the laser emitter and the camera device are comparable, so that the shooting direction of the camera device is perpendicular to the laser emitting direction of the laser emitter.

[0008] Furthermore, the oil tank is filled with transformer oil to be tested, and the filling height of the transformer oil to be tested is higher than the installation height of the laser transmitter and the camera device.

[0009] Furthermore, the laser emitter is a tunable laser with variable laser wavelength; the laser wavelength emitted by the laser emitter is adapted to the size of water molecules in the transformer oil, so as to irradiate free water molecules in the transformer oil to form a light spot.

[0010] Furthermore, the weak ultrasonic agitator includes a weak ultrasonic transducer and a weak ultrasonic transmitter, the weak ultrasonic transducer is embedded in the bottom of the oil tank, the weak ultrasonic transmitter is electrically connected to the weak ultrasonic transducer, the weak ultrasonic signal generated by the weak ultrasonic transmitter is sent to the weak ultrasonic transducer, and the transformer oil contained in the oil tank is slightly oscillated and stirred by the weak ultrasonic transducer, so that the trace water contained in the transformer oil is evenly distributed under the slight oscillation and stirring.

[0011] Furthermore, a combined automatic calibration device is also provided, which includes four pre-prepared standard oil samples with different trace water contents, four corresponding miniature standard oil sample injectors, four driving mechanisms, four miniature solenoid valves and a control module; the four standard oil samples are: a standard oil sample with a low trace water content in the range of 0-10ul / l, a standard oil sample with a medium-low trace water content in the range of 11-20ul / l, a standard oil sample with a medium-high trace water content in the range of 21-30ul / l and a standard oil sample with a water content in the range of The invention relates to a standard oil sample with a high micro-water content of 31-60ul / l; four standard oil samples are pre-loaded into corresponding micro standard oil sample injectors respectively, and driving mechanisms are installed on the four micro standard oil sample injectors respectively to drive their actions; four micro solenoid valves are installed at the outlets of the corresponding micro standard oil sample injectors respectively, and the outlets of the respective micro solenoid valves are respectively installed with slender outlet pipes and extend to the oil tank to inject the corresponding standard oil sample into the oil tank; when the transformer oil micro-water measuring device completes the detection of the water content in the transformer oil to be tested, the transformer oil micro-water measuring device is used to measure the water content of the transformer oil to be tested. The computer of the measuring device transmits the detection data to the control module, and the control module determines the water content range to which the detection data belongs: low micro-water content, medium-low micro-water content, medium-high micro-water content or high micro-water content, and after the transformer oil to be tested in the oil tank is emptied, the micro-electromagnetic valve at the outlet of the micro-standard oil sample injector corresponding to the water content range is controlled to open, and then the micro-standard oil sample injector is driven by the corresponding driving mechanism to inject the corresponding standard oil sample into the oil tank, and the standard oil sample is detected by the transformer oil micro-water measuring device to calibrate the accuracy of the detection of the transformer oil micro-water measuring device; if the difference between the water content of the standard oil sample detected by the transformer oil micro-water measuring device and the real water content of the standard oil sample is within the set allowable range, it means that the detection data of the transformer oil micro-water measuring device is accurate and reliable; if the difference between the detected water content and the real water content exceeds the allowable range, it means that the detection data of the transformer oil micro-water measuring device is distorted, and the control module issues an alarm to prompt the operator to check and calibrate the transformer oil micro-water measuring device, thereby ensuring the accuracy and reliability of the water content detection of each water content range.

[0012] The present invention also provides a transformer oil micro-water measurement method using the above device, comprising:

[0013] S1. Add the transformer oil to be tested into the oil tank to the set height and close the darkroom;

[0014] S2, start the weak ultrasonic stirrer to slightly oscillate and stir the transformer oil to be tested in the oil tank;

[0015] S3, turning on the laser transmitter, the laser transmitter transmits a laser beam to the oil tank, the laser beam penetrates the oil tank and the transformer oil in the oil tank;

[0016] S4, capturing an image of a scattered light column in transformer oil by a camera device;

[0017] S5. Performing image analysis on the image captured by the camera device through a computer to obtain the moisture content in the transformer oil.

[0018] Further, in step S5, the specific method of performing image analysis on the captured image to obtain the moisture content in the transformer oil is:

[0019] S501, in order to avoid interference from laser refraction at the oil tank wall and corners, the middle image is cut out from the captured image, leaving only the middle part of the scattered light column;

[0020] S502, graying and binarizing the cropped image according to a set light sensitivity threshold;

[0021] S503, extracting the area of ​​the white light spot from the processed image, and inputting the established data model of the correspondence between the moisture content and the light spot area, so as to obtain the moisture content in the transformer oil.

[0022] Furthermore, the laser transmitter adopts a tunable laser with a variable laser wavelength; after adding the transformer oil to be tested into the oil tank and turning on the laser transmitter, the laser wavelength is changed intermittently within a certain range adapted to the size of water molecules; each time the laser wavelength is changed, steps S4-S5 are repeated to obtain all moisture content values ​​under different laser wavelengths; finally, the first k moisture content values ​​with the largest values ​​are taken to calculate the average value, which is used as the final moisture content in the transformer oil.

[0023] Compared with the prior art, the present invention has the following beneficial effects: the present invention provides a transformer oil micro-water measurement device and method, the device and method adopt a new transformer oil micro-water measurement method, which can be used to detect the moisture content of transformer oil in the equipment. The detection and judgment methods of the device and method are simple, which can not only improve the detection accuracy, but also be easy to operate, and have strong practicality and broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a front view (cut away) of the device structure of an embodiment of the present invention;

[0025] Figure 2 is a top view (cut away) of the device structure of an embodiment of the present invention;

[0026] Figure 3 is an image captured in an embodiment of the present invention;

[0027] Figure 4 is a cropped image in an embodiment of the present invention;

[0028] Figure 5 is an image after grayscale and binarization processing in an embodiment of the present invention;

[0029] Figure 6 1 is a circuit diagram of a weak ultrasonic stirrer in an embodiment of the present invention.

[0030] In the figure: 1. Camera device; 2. Oil tank; 3. Darkroom; 4. Laser transmitter; 5. Support platform; 6. Temperature probe; 7. Weak ultrasonic transducer; 8. Weak ultrasonic transmitter. DETAILED DESCRIPTION

[0031] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0032] It should be noted that the following detailed descriptions are exemplary and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0033] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0034] like Figure 1-2 As shown, this embodiment provides a transformer oil micro-water measuring device, including a darkroom 3, a transparent oil tank 2 is arranged in the darkroom 3, a laser emitter 4 and a camera device 1 are arranged outside the oil tank 2, and the laser emission direction of the laser emitter 4 is perpendicular to the shooting direction of the camera device 1; a weak ultrasonic agitator is also arranged in the darkroom 3, which is used to slightly oscillate and stir the transformer oil in the oil tank 2 to promote uniform distribution of the micro-water contained in the transformer oil.

[0035] Preferably, the laser emitter 4 and the camera device 1 are horizontally arranged at different positions outside the oil tank 2, and the installation heights of the laser emitter 4 and the camera device 1 are equal, so that the shooting direction of the camera device 1 is perpendicular to the laser emission direction of the laser emitter 4. In this embodiment, the laser emitter 4 is arranged at the right position outside the oil tank 2, and the camera device 1 is arranged at the rear position outside the oil tank 2. In this embodiment, the oil tank 2 is made of transparent acrylic resin.

[0036] The oil tank 2 is filled with transformer oil to be tested, and the filling height of the transformer oil to be tested is higher than the installation height of the laser transmitter 4 and the camera device 1 .

[0037] In this embodiment, the camera device 1 uses a high-definition camera. The camera device 1 is connected to a computer, and the computer determines the moisture content in the transformer oil through image analysis.

[0038] In this embodiment, a support platform 5 is provided in the darkroom 3, and the oil tank 2 is placed on the support platform 5. A heating pad is provided between the upper surface of the support platform 5 and the lower bottom surface of the oil tank 2. A temperature measuring probe 6 is provided in the oil tank 2. The laser emitter 4, the camera device 1, the heating pad and the temperature measuring probe 6 are all electrically connected to the computer.

[0039] like Figure 6 As shown, the weak ultrasonic stirrer comprises a weak ultrasonic transducer 7 and a weak ultrasonic transmitter 8, the weak ultrasonic transducer 7 is embedded in the outer side of the bottom of the oil tank 2 (a corresponding groove can be provided on the support platform 5 to accommodate the weak ultrasonic transducer 7), the weak ultrasonic transmitter 8 is arranged near the periphery of the oil tank 2 (it can also be arranged outside the darkroom 3), the weak ultrasonic transmitter 8 is electrically connected to the weak ultrasonic transducer 7, the weak ultrasonic signal generated by the weak ultrasonic transmitter 8 is sent to the weak ultrasonic transducer 7, and the transformer oil contained in the oil tank 2 is slightly oscillated and stirred by the weak ultrasonic transducer 7, so that the micro-water contained in the transformer oil is evenly distributed under slight oscillation and stirring. The weak ultrasonic stirrer has the advantages of low energy, no damage, and non-invasive. In the present embodiment, a miniature weak ultrasonic stirrer can be adopted.

[0040] In this embodiment, the transformer oil micro-water measuring device is further equipped with a combined automatic calibration device, which includes four pre-prepared standard oil samples with different micro-water contents, four corresponding matching miniature standard oil sample injectors, four driving mechanisms, four miniature solenoid valves and a control module. The four standard oil samples are: a standard oil sample with a low micro-water content in the water content range of 0-10ul / l, a standard oil sample with a medium-low micro-water content in the water content range of 11-20ul / l, a standard oil sample with a medium-high micro-water content in the water content range of 21-30ul / l, and a standard oil sample with a high micro-water content in the water content range of 31-60ul / l. Four kinds of standard oil samples are pre-loaded into corresponding micro standard oil sample injectors respectively, and driving mechanisms are installed on the four micro standard oil sample injectors respectively to drive their actions; four micro solenoid valves are installed at the outlets of corresponding micro standard oil sample injectors respectively, and the outlets of each micro solenoid valve are respectively installed with slender outlet pipes and extend to the oil tank to inject the corresponding standard oil samples into the oil tank; when the transformer oil micro-water measuring device completes the detection of the moisture content in the transformer oil to be tested, the computer of the transformer oil micro-water measuring device transmits the detection data to the control module, and the control module determines the moisture content range to which the detection data belongs: low micro-water content, medium-low micro-water content, medium-high micro-water content or high micro-water content, and after the transformer oil to be tested in the oil tank is emptied, the outlet of the micro standard oil sample injector corresponding to the moisture content range is controlled. The micro solenoid valve is opened, and then the micro standard oil sample injector is driven by the corresponding driving mechanism to inject the corresponding standard oil sample into the oil tank, and the standard oil sample is detected by the transformer oil micro-water measuring device to calibrate the detection accuracy of the transformer oil micro-water measuring device; if the difference between the moisture content of the standard oil sample detected by the transformer oil micro-water measuring device and the actual moisture content of the standard oil sample is within the set allowable range, it means that the detection data of the transformer oil micro-water measuring device is accurate and reliable; if the difference between the detected moisture content and the actual moisture content exceeds the allowable range, it means that the detection data of the transformer oil micro-water measuring device is distorted, and the control module issues an alarm to prompt the operator to check and calibrate the transformer oil micro-water measuring device, thereby ensuring the accuracy and reliability of moisture content detection in each moisture content range.

[0041] According to the Tyndall effect, when the wavelength of the light wave is greater than the particle irradiated by the light channel during the irradiation, the light will be scattered, and the closer the wavelength of the light is to the size of the particle, the more obvious the scattering phenomenon is. By selecting a laser irradiator with a suitable wavelength, the free water in the oil can be irradiated, thereby forming a light spot in the irradiation channel. Therefore, in this device, the laser emitter 4 is selected according to the size of the water molecules in the transformer oil, so that the wavelength of the laser emitted by the laser emitter 4 is adapted to the size of the water molecules in the transformer oil, thereby irradiating the free water molecules and particulate impurities in the transformer oil, and forming a light spot in the irradiation channel.

[0042] Preferably, in order to further improve the accuracy of detection, the laser transmitter used in this embodiment is a tunable laser with variable wavelength of emitted laser light. How to improve the detection accuracy based on the tunable laser will be further described below.

[0043] This embodiment also provides a transformer oil micro-water measurement method using the above device, comprising:

[0044] S1. Add the transformer oil to be tested into the oil tank 2 to the set height and close the darkroom 3.

[0045] S2, start the weak ultrasonic stirrer to slightly oscillate and stir the transformer oil to be tested in the oil tank 2.

[0046] S3, turn on the laser emitter 4, the laser emitter 4 emits a laser beam to the oil tank 2, and the laser beam penetrates the oil tank 2 and the transformer oil in the oil tank 2. In this process, the Tyndall effect is used, that is, when a beam of light passes through the colloid, a bright "pathway" can be observed in the colloid from the direction perpendicular to the incident light, and a scattered light column is formed in the transformer oil.

[0047] S4. Using the camera device 1 to capture an image of the scattered light column in the transformer oil.

[0048] S5. Perform image analysis on the image taken by the camera device 1 through a computer, and obtain the moisture content in the transformer oil according to the situation of the scattered light column.

[0049] The specific method of performing image analysis on the captured images to obtain the moisture content in the transformer oil is:

[0050] S501: The image captured by the camera device 1 is as follows: Figure 3 As shown in the figure. Due to the laser refraction phenomenon on the transparent oil tank wall and corners, these two scattered light columns cannot be used as the basis for oil moisture analysis. They must be excluded first to avoid the interference of laser refraction. Therefore, the middle image is cropped from the captured image to remove the interference items, retain the valid data, and only leave the middle part of the scattered light column. The cropped image is shown in the figure. Figure 4 shown.

[0051] S502: grayscale and binarize the cropped image according to the set light sensitivity threshold. Figure 5 shown.

[0052] S503, extracting the area of ​​the white light spot from the processed image, and inputting the established data model of the correspondence between the moisture content and the light spot area, so as to obtain the moisture content in the transformer oil.

[0053] As mentioned above, the closer the wavelength of the laser is to the size of the particles, the more obvious the scattering phenomenon is. However, the situation of transformer oil in the equipment being doped with water and impurities after use will be different. In order to improve the detection accuracy, the wavelength of the laser should be adapted to the particle size in the transformer oil as much as possible. Therefore, the laser transmitter in this embodiment adopts a tunable laser with a variable laser wavelength. After adding the transformer oil to be detected to the oil tank 2 and turning on the laser transmitter, the laser wavelength is changed intermittently within a certain range that is adapted to the size of the water molecules. Each time the laser wavelength is changed, steps S4-S5 are repeated to obtain all moisture content values ​​under different laser wavelengths. Finally, the first k moisture content values ​​with the largest values ​​are taken to calculate the average value as the final moisture content in the transformer oil.

[0054] The above is only a preferred embodiment of the present invention, and does not limit the present invention in other forms. Any technician familiar with the profession may use the above disclosed technical content to change or modify it into an equivalent embodiment with equivalent changes. However, any simple modification, equivalent change and modification made to the above embodiment according to the technical essence of the present invention without departing from the technical solution of the present invention still belongs to the protection scope of the technical solution of the present invention.

Claims

1. A transformer oil micro-water measuring device, characterized in that: The invention comprises a darkroom (3), wherein a transparent oil tank (2) is arranged in the darkroom (3), and a laser emitter (4) and a camera device (1) are arranged outside the oil tank (2), wherein the laser emission direction of the laser emitter (4) and the shooting direction of the camera device (1) are perpendicular to each other; and a weak ultrasonic stirrer is also arranged in the darkroom (3) for slightly oscillating and stirring the transformer oil in the oil tank (2) so as to promote uniform distribution of the micro-water contained in the transformer oil.

2. A transformer oil micro-water measuring device according to claim 1, characterized in that: A support platform (5) is arranged in the darkroom (3), and the oil tank (2) is placed on the support platform (5); a heating pad is arranged between the upper surface of the support platform (5) and the lower bottom surface of the oil tank (2); a temperature measuring probe (6) is arranged in the oil tank (2); and the laser emitter (4), the camera device (1), the heating pad and the temperature measuring probe (6) are all electrically connected to a computer.

3. A transformer oil micro-water measuring device according to claim 1, characterized in that: The laser emitter (4) and the camera device (1) are horizontally arranged at different positions outside the oil tank (2), and the installation heights of the laser emitter (4) and the camera device (1) are similar, so that the shooting direction of the camera device (1) is perpendicular to the laser emission direction of the laser emitter (4).

4. A transformer oil micro-water measuring device according to claim 1, characterized in that: The oil tank (2) is filled with transformer oil to be tested, and the filling height of the transformer oil to be tested is higher than the installation height of the laser transmitter (4) and the camera device (1).

5. A transformer oil micro-water measuring device according to claim 1, characterized in that: The laser emitter (4) is a tunable laser with a variable laser wavelength; the laser wavelength emitted by the laser emitter (4) is adapted to the size of water molecules in transformer oil, so as to illuminate free water molecules in the transformer oil to form light spots.

6. A transformer oil micro-water measuring device according to claim 1, characterized in that: The weak ultrasonic stirrer comprises a weak ultrasonic transducer (7) and a weak ultrasonic transmitter (8); the weak ultrasonic transducer (7) is embedded in the bottom of the oil tank (2); the weak ultrasonic transmitter (8) is electrically connected to the weak ultrasonic transducer (7); a weak ultrasonic signal generated by the weak ultrasonic transmitter (8) is sent to the weak ultrasonic transducer (7); and the transformer oil contained in the oil tank (2) is slightly oscillated and stirred by the weak ultrasonic transducer (7), so that the micro-water content in the transformer oil is evenly distributed under the slight oscillation and stirring.

7. A transformer oil micro-water measuring device according to claim 1, characterized in that: A combined automatic calibration device is also provided, which comprises four pre-prepared standard oil samples with different micro-water contents, four corresponding miniature standard oil sample injectors, four driving mechanisms, four miniature solenoid valves and a control module; the four standard oil samples are: a standard oil sample with a low micro-water content in the water content range of 0-10ul / l, a standard oil sample with a medium-low micro-water content in the water content range of 11-20ul / l, a standard oil sample with a medium-high micro-water content in the water content range of 21-30ul / l and a standard oil sample with a high micro-water content in the water content range of 31-60ul / l; the four standard oil samples are respectively pre-loaded into corresponding miniature standard oil sample injectors, and driving mechanisms are correspondingly installed on the four miniature standard oil sample injectors to drive their actions; Four micro solenoid valves are respectively installed at the outlets of the corresponding micro standard oil sample injectors, and the outlets of the respective micro solenoid valves are respectively installed with slender outlet pipes extending to the oil tank so as to inject the corresponding standard oil sample into the oil tank; when the transformer oil micro-water measuring device completes the detection of the moisture content in the transformer oil to be tested, the computer of the transformer oil micro-water measuring device transmits the detection data to the control module, and the control module determines whether the detection data belongs to the moisture range: low micro-water content, medium-low micro-water content, medium-high micro-water content or high micro-water content, and after the transformer oil to be tested in the oil tank is emptied, the micro solenoid valve at the outlet of the micro standard oil sample injector corresponding to the moisture range is controlled to open, and then the micro standard oil sample is driven by the corresponding driving mechanism. The sample injector injects the corresponding standard oil sample into the oil tank, and the standard oil sample is detected by the transformer oil micro-water measuring device to calibrate the accuracy of the detection of the transformer oil micro-water measuring device; if the difference between the moisture content of the standard oil sample detected by the transformer oil micro-water measuring device and the actual moisture content of the standard oil sample is within the set allowable range, it means that the detection data of the transformer oil micro-water measuring device is accurate and reliable; if the difference between the detected moisture content and the actual moisture content exceeds the allowable range, it means that the detection data of the transformer oil micro-water measuring device is distorted, and the control module alarms to prompt the operator to check and calibrate the transformer oil micro-water measuring device, thereby ensuring the accuracy and reliability of moisture content detection in each moisture content range.

8. A method for measuring micro-water content in transformer oil using the device according to any one of claims 1 to 7, characterized in that: include: S1, adding transformer oil to be tested into the oil tank (2) to a set height, and closing the darkroom (3); S2, starting a weak ultrasonic stirrer to gently oscillate and stir the transformer oil to be tested in the oil tank (2); S3, turning on the laser emitter (4), the laser emitter (4) emitting a laser beam toward the oil tank (2), the laser beam penetrating the oil tank (2) and the transformer oil in the oil tank (2); S4, photographing an image of a scattered light column in the transformer oil by means of a camera device (1); S5. Performing image analysis on the image captured by the camera device (1) by means of a computer to obtain the moisture content in the transformer oil.

9. A transformer oil micro-water measurement method according to claim 8, characterized in that: In step S5, the specific method of performing image analysis on the captured image to obtain the moisture content in the transformer oil is: S501, in order to avoid interference from laser refraction at the oil tank wall and corners, the middle image is cut out from the captured image, leaving only the middle part of the scattered light column; S502, graying and binarizing the cropped image according to a set light sensitivity threshold; S503, extracting the area of ​​the white light spot from the processed image, and inputting the established data model of the correspondence between the moisture content and the light spot area, so as to obtain the moisture content in the transformer oil.

10. A transformer oil micro-water measurement method according to claim 8, characterized in that: The laser transmitter (4) uses a tunable laser with a variable laser wavelength. After adding the transformer oil to be tested into the oil tank (2) and turning on the laser transmitter, the laser wavelength is changed intermittently within a certain range that is compatible with the size of water molecules. Each time the laser wavelength is changed, steps S4-S5 are repeated to obtain all moisture content values ​​under different laser wavelengths. Finally, the first k moisture content values ​​with the largest values ​​are taken to calculate the average value, which is used as the final moisture content in the transformer oil.

Images