Low-voltage transformer oil measuring device

Abstract

The low-voltage transformer oil measuring device comprises a shell and a range change adjusting assembly, the shell is of a rectangular box structure with an opening in the left side, a main support is installed at the opening in the left side of the shell, a spring loading belt is arranged on the left side of the main support, a floater is connected to the lower portion of the spring loading belt, and the floater is installed in a jacketed pipe in a sleeved mode; a range change adjusting assembly is arranged in the shell and connected with the inner wall of the shell through a bearing seat, and a driven gear is in power connection with the upper portion of the range change adjusting assembly. A moving frame of a Z-shaped structure is arranged on the left side of the main support, a sensor is installed above the moving frame, and the sensor is connected with the driven gear through a rotating shaft. The sensor is connected with a tubular oil level gauge of the transformer; the device has the advantages that the structure is reasonable, multi-range adjustable oil level detection is achieved, the influence of oil level fluctuation is effectively avoided, and the detection precision is improved.

Description

Technical Field

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

[0002] Oil level is one of the important monitoring parameters of power transformers. It is of great significance to timely detect whether the oil level is too low or too high and take corresponding measures to ensure the safe operation of power transformers. When the oil level is too high, it may cause the internal oil pressure of the transformer to increase, and it may also cause oil overflow; when the oil level is too low, the oil level will further drop when the transformer is running at low load or the transformer is out of service, or when the weather turns cold. When the oil level is below the transformer cover, the lead wire or the iron core will be exposed to the air, and there is a risk of internal flashover; at the same time, the increase in the contact area between oil and air will rapidly reduce the insulation performance of the insulating oil. It can be seen that the transformer requires a certain oil level during operation, and regular inspections must be carried out during operation. The disadvantages of traditional oil level gauges are that they have a single range and a small detection range, and cannot effectively deal with oil level fluctuations. Especially during the operation of the transformer, the volume of the transformer oil will change frequently with the change of the body temperature, thereby interfering with the oil level gauge connecting rod, resulting in distorted oil level indication, false alarm signals, or the oil level gauge cannot indicate normally when the actual oil level is already abnormal; in addition, the transformer oil level detection mainly adopts regular inspections by inspectors, and the transformer oil level characteristic data is obtained manually on a regular basis to judge the transformer operation status. This method not only wastes human resources, but also may fail to detect the abnormal transformer oil level in time and cause failures. The manual method cannot truly meet the basic requirements of safe and stable operation of the system; therefore, it is very necessary to provide a low-voltage transformer oil measuring device with a reasonable structure, multi-range adjustable oil level detection, effective avoidance of oil level fluctuations, and improved detection accuracy. Summary of the invention

[0003] The purpose of the present invention is to overcome the deficiencies of the prior art and to provide a low voltage transformer oil measuring device with a reasonable structure, multi-range adjustable oil level detection, effective avoidance of the influence of oil level fluctuations and improved detection accuracy.

[0004] The objective of the present invention is achieved in this way: a low-voltage transformer oil measuring device comprises a shell and a range change adjustment component, the shell is a rectangular box structure with an opening on the left side and a main bracket is installed at the opening on the left side, a spring-loaded belt is arranged on the left side of the main bracket, a float is connected below the spring-loaded belt, and the float sleeve is installed inside the jacket tube; a range change adjustment component is arranged inside the shell, the range change adjustment component is connected to the inner wall of the shell through a bearing seat, and a driven gear is connected to the top of the range change adjustment component; a "Z"-shaped mobile frame is arranged on the left side of the main frame, a sensor is installed above the mobile frame, and the sensor is connected to the driven gear through a rotating shaft; the sensor is connected to the tubular oil level gauge of the transformer.

[0005] The main support includes a support plate of an "Ω"-shaped structure, and longitudinal openings are opened on both upper and lower sides of the support plate; the support plate is movably connected to the rotating shaft through the upper longitudinal opening and is connected to the spring-loaded belt through the lower longitudinal opening.

[0006] A convex rib is arranged on the outside of the rotating shaft along the axial direction, and a sleeve for connecting the driven gear is arranged on the outside of the rotating shaft. A groove is arranged inside the sleeve, and the sleeve cooperates with the convex rib through the groove to realize the movement of the sleeve along the axial direction of the rotating shaft, and the sleeve can drive the rotating shaft to rotate.

[0007] The spring loaded belt comprises a U-shaped opening frame arranged on one side below the main support, a spring winding belt assembly is arranged inside the U-shaped opening frame, a pull belt is wrapped around the outside of the spring winding belt assembly, the pull belt is connected to the float through a connecting buckle, the spring winding belt assembly is connected to the main support through a nut, a driving gear is connected to the right side of the spring winding belt assembly through the nut shaft, and the driving gear is dynamically connected to the range change adjustment assembly.

[0008] The jacket pipe comprises a hollow pipe with a hexagonal structure, and a plurality of through holes are arranged on the outer circumference of the hollow pipe from top to bottom; the float is a hexagonal structure matching the hollow pipe.

[0009] The range change adjustment component includes a central shaft connected to the bearing seat, and a plurality of gear sets arranged vertically are arranged in sequence and spaced apart on the central shaft. Adjacent gear sets are centrally symmetrical with each other, and the gear sets include large gears and small gears that mesh with each other.

[0010] The middle part of the mobile frame is connected to the main support through a lifting assembly, and the free end of the lower end of the mobile frame is located inside the limiting guide seat; a polished rod is arranged above the inside of the shell, a fork assembly is sleeved outside the polished rod, and a lateral moving device is arranged above the fork assembly.

[0011] The lifting assembly includes an upper plate connected to the main support and a lower waist-shaped orifice plate connected to the movable frame, a slide groove is arranged inside the left side of the upper plate, a group of first rollers are arranged inside the slide groove, the first rollers are mounted on the movable plate, and a hydraulic device is arranged on the right side of the movable plate; the upper plate and the lower waist-shaped orifice plate are connected by a first connecting rod and a second connecting rod that are cross-hinged with each other, one end of the first connecting rod is hinged to the movable plate, and the other end is connected to the lower waist-shaped orifice plate through the second roller, one end of the second connecting rod is hinged to the upper plate, and the other end is connected to the lower waist-shaped orifice plate through the second roller.

[0012] The fork assembly includes a sliding sleeve that is slidably connected to the bare rod, a connecting seat connected to a lateral moving device is arranged above the sliding sleeve, and a fork is arranged below the sliding sleeve; the lateral moving device is a gear rack matching assembly, a screw and sleeve matching assembly, a hydraulic rod assembly, a telescopic rod assembly and other structures that can achieve lateral movement.

[0013] The low-voltage transformer oil online detection method adopts the low-voltage transformer oil measuring device as described above to be connected with a tubular oil level gauge, and realizes the low-voltage transformer oil level online detection based on the oil level video detection algorithm. The method comprises the following steps:

[0014] Step 1: Obtain the transformer oil level video under cloudy conditions;

[0015] Step 2: Perform image denoising preprocessing on the acquired oil level video, and then extract the oil level video image features through image enhancement algorithm to detect the oil level height;

[0016] Step 3: Analyze the oil level change trend. If the oil level analysis result is higher than the first limit and lower than the second limit, an alarm signal is given; if it is lower than the first limit, it indicates that a serious fault has occurred in the transformer.

[0017] The beneficial effects of the present invention are as follows: the present invention is a low-voltage transformer oil measuring device. During use, the device of the present invention is connected to the tubular oil level gauge of the transformer through a sensor. The float moves up and down in a stationary jacket tube according to the fluid level. The length of the jacket tube corresponds to the maximum movement of the float. In the process of moving up and down, the float drives the active gear to rotate through the spring loading belt. The active gear drives the driven gear to rotate through the range change adjustment component. The driven gear drives the rotating shaft to rotate through the shaft sleeve. The sensor monitors the change of the rotating shaft in real time and displays the change through the tubular oil level gauge, thereby realizing real-time monitoring of the transformer oil level, which is convenient for the staff to check the oil level intuitively and quickly. At the same time, the low-voltage transformer oil online detection method of the present invention is used to perform oil level video detection on the tubular oil level gauge, thereby realizing remote monitoring of the oil level, so as to facilitate the dispatch of staff to maintain the transformer oil tank that does not meet the work requirements; when it is necessary When improving the detection sensitivity, the moving frame is driven upward by the lifting component, and the moving frame drives the sensor and the rotating shaft to move upward in the longitudinal opening above the main bracket, so that the shaft sleeve contacts the fork assembly, and then the fork assembly and the shaft sleeve are driven to move to the leftmost side by the lateral moving device, thereby reducing the number of gear sets of the range change adjustment assembly, and then the driven gear is driven downward by the lifting component, so that only one set of gear sets is used for transmission between the driving gear and the driven gear, thereby improving the detection accuracy and sensitivity, and greatly improving the reliability; when it is necessary to avoid the error caused by oil level fluctuation affecting the detection result, it is only necessary to move the driven gear to the right side and change the number of gear sets transmitted between the driving gear and the driven gear, so as to achieve better response to the influence of oil level fluctuation and improve the detection accuracy; the present invention has the advantages of reasonable structure, multi-range adjustable oil level detection, effective avoidance of oil level fluctuation influence, and improved detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a front view of the present invention.

[0019] Figure 2 For the present invention Figure 1 Schematic diagram of part of the structure Figure 1 .

[0020] Figure 3 For the present invention Figure 2 Front view of .

[0021] Figure 4 For the present invention Figure 1 Schematic diagram of part of the structure Figure 2 .

[0022] Figure 5 The structural diagram of the lifting assembly of the present invention is Figure 1 .

[0023] Figure 6The structural diagram of the lifting assembly of the present invention is Figure 2 .

[0024] Figure 7 It is a structural schematic diagram of the fork assembly of the present invention.

[0025] Figure 8 It is a flow chart of the online detection method of the present invention.

[0026] In the figure: 1, housing 2, main bracket 21, support plate 22, longitudinal opening 3, spring loaded belt 31, U-shaped opening frame 32, spring belt assembly 33, pull belt 34, connecting buckle 35, nut 36, driving gear 4, float 5, jacket tube 51, hollow tube 52, through hole 6, range change adjustment assembly 61, gear set 611, large gear 612, small gear 62, central shaft 7, bearing seat 8, driven gear 9, sleeve 10, opening Groove 11, rotating shaft 12, convex rib 13, sensor 14, moving frame 15, limiting guide seat 16, lifting assembly 601, upper plate 602, lower waist-shaped orifice plate 603, slide groove 604, first roller 605, moving plate 606, hydraulic device 607, first connecting rod 608, second connecting rod 609, second roller 17, fork assembly 71, sliding sleeve 72, connecting seat 73, fork 18, light rod 19, and lateral moving device. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings.

[0028] Example 1

[0029] like Figure 1-7 As shown, a low-voltage transformer oil measuring device comprises a shell 1 and a range change adjustment component 6, wherein the shell 1 is a rectangular box structure with an opening on the left side and a main bracket 2 is installed at the opening on the left side, a spring-loaded belt 3 is arranged on the left side of the main bracket 2, a float 4 is connected below the spring-loaded belt 3, and the float 4 is sleeved and installed inside a jacket tube 5; a range change adjustment component 6 is arranged inside the shell 1, the range change adjustment component 6 is connected to the inner wall of the shell 1 through a bearing seat 7, and a driven gear 8 is dynamically connected above the range change adjustment component 6; a "Z"-shaped moving frame 14 is arranged on the left side of the main bracket 2, a sensor 13 is installed above the moving frame 14, and the sensor 13 is connected to the driven gear 8 through a rotating shaft 11; the sensor 13 is connected to a tubular oil level gauge of the transformer.

[0030] The main support 2 includes a support plate 21 of an "Ω"-shaped structure, and longitudinal openings 22 are opened on both the upper and lower sides of the support plate 21; the support plate 21 is movably connected to the rotating shaft 11 through the upper longitudinal opening 22 and is connected to the spring-loaded belt 3 through the lower longitudinal opening 22.

[0031] In this embodiment, the spring-loaded belt can change its position up and down in the longitudinal opening below the support plate. Since the gear set is composed of a large gear and a small gear arranged up and down, when the gear set of the range change adjustment component is engaged with the driving gear through the large gear, the spring-loaded belt is installed in the lower position in the longitudinal opening; when the gear set of the range change adjustment component is engaged with the driving gear through the small gear, the spring-loaded belt is installed in the upper position in the longitudinal opening, which is convenient for adapting to the range change adjustment component in different installation conditions.

[0032] The rotating shaft 11 is provided with a convex rib 12 on the outside along the axial direction, and the rotating shaft 11 is provided with a sleeve 9 on the outside for connecting with the driven gear 8. The sleeve 9 is provided with a slot 10 on the inside. The sleeve 9 is moved along the axial direction of the rotating shaft 11 through the cooperation between the slot 10 and the convex rib 12, and the sleeve 9 can drive the rotating shaft 11 to rotate.

[0033] The spring loaded belt 3 includes a U-shaped opening frame 31 arranged on one side below the main bracket 2, a spring winding belt assembly 32 is arranged inside the U-shaped opening frame 31, a pull belt 33 is wrapped around the outside of the spring winding belt assembly 32, the pull belt 33 is connected to the float 4 through a connecting buckle 34, the spring winding belt assembly 32 is connected to the main bracket 2 through a nut 35, and a driving gear 36 is connected to the shaft of the nut 35 on the right side of the spring winding belt assembly 32, and the driving gear 36 is dynamically connected to the range change adjustment assembly 6.

[0034] The jacket tube 5 includes a hollow tube 51 of a hexagonal structure, and a plurality of through holes 52 are arranged on the outer circumference of the hollow tube 51 from top to bottom; the float 4 is a hexagonal structure matching the hollow tube 51 .

[0035] In this embodiment, the jacket tube is used to guide the float and damp the waves, and the through hole of the jacket tube can reduce the impact of oil level fluctuations; the hexagonal float cooperates with the jacket tube, which can effectively prevent the pull belt of the spring-loaded belt from rotating and twisting in the jacket tube; the length of the jacket tube corresponds to the maximum movement of the float.

[0036] The range change adjustment component 6 includes a central shaft 62 connected to the bearing seat 7, and a plurality of gear sets 61 arranged vertically are arranged in sequence and spaced apart from each other on the central shaft 62. Adjacent gear sets 61 are centrally symmetrical with each other, and the gear sets 61 include a large gear 611 and a small gear 612 that mesh with each other.

[0037] The middle part of the movable frame 14 is connected to the main support 2 through a lifting assembly 16, and the lower free end of the movable frame 14 is located inside the limiting guide seat 15; a light rod 18 is arranged above the inside of the shell 1, and a fork assembly 17 is sleeved on the outside of the light rod 18, and a lateral moving device 19 is arranged above the fork assembly 17.

[0038] The lifting assembly 16 includes an upper plate 601 connected to the main support 2 and a lower waist-shaped orifice plate 602 connected to the movable frame 14, a slide groove 603 is arranged inside the left side of the upper plate 601, a group of first rollers 604 are arranged inside the slide groove 603, the first rollers 604 are installed on the movable plate 605, and a hydraulic device 606 is arranged on the right side of the movable plate 605; the upper plate 601 and the lower waist-shaped orifice plate 602 are connected by a first connecting rod 607 and a second connecting rod 608 that are cross-hinged with each other, one end of the first connecting rod 607 is hinged to the movable plate 605, and the other end is connected to the lower waist-shaped orifice plate 602 through the second roller 609, one end of the second connecting rod 608 is hinged to the upper plate 601, and the other end is connected to the lower waist-shaped orifice plate 602 through the second roller 609.

[0039] In this embodiment, the working principle of the lifting assembly is: start the hydraulic device, the hydraulic device drives the movable plate to slide in the slide groove through the first roller. When the movable plate moves horizontally, the lower waist-shaped hole plate will be driven up and down through the first and second connecting rods that are crossed and hinged to each other, thereby driving the movable frame to move up and down.

[0040] The fork assembly 17 includes a sliding sleeve 71 that is slidably connected to the light rod 18, a connecting seat 72 that is connected to the lateral moving device 19 is arranged above the sliding sleeve 71, and a fork 73 is arranged below the sliding sleeve 71; the lateral moving device 19 is a gear rack matching assembly, a screw and thread sleeve matching assembly, a hydraulic rod assembly, a telescopic rod assembly and other structures that can achieve lateral movement.

[0041] The present invention is a low-voltage transformer oil measuring device. During use, the device of the present invention is connected to the tubular oil level gauge of the transformer through the sensor 13. The float 4 moves up and down in the static jacket tube 5 according to the fluid level. During the up and down movement, the float 4 drives the driving gear 36 to rotate through the spring-loaded belt 3. The driving gear 36 drives the driven gear 8 to rotate through the range change adjustment component 6. The driven gear 8 drives the rotating shaft 11 to rotate through the shaft sleeve 9. The sensor 13 monitors the change of the rotating shaft 11 in real time and displays the change through the tubular oil level gauge, thereby realizing real-time monitoring of the transformer oil level, which is convenient for the staff to check the oil level intuitively and quickly. At the same time, the tubular oil level gauge is subjected to oil level video detection through the low-voltage transformer oil online detection method of the present invention, thereby realizing remote monitoring of the oil level, so as to facilitate the dispatch of staff to maintain the transformer oil tank that does not meet the work requirements; when it is necessary to improve the detection sensitivity, the lifting component 16 drives the mobile frame to move. 14 moves up, the mobile frame 14 drives the sensor 13 and the rotating shaft 11 to move upward in the longitudinal opening 22 above the main bracket 2, so that the shaft sleeve 9 contacts the fork assembly 17, and then the fork assembly 17 and the shaft sleeve 9 are driven to move to the far left through the lateral moving device 19, reducing the number of gear sets 61 of the range change adjustment assembly 6, and then the driven gear 8 is driven to move downward through the lifting assembly 16, so that there is only one set of gear sets 61 for transmission between the driving gear 36 and the driven gear 8, thereby improving the detection accuracy and sensitivity, and greatly improving the reliability; when it is necessary to avoid the error caused by oil level fluctuation affecting the detection result, it is only necessary to move the driven gear 8 to the right side, and change the number of gear sets 61 transmitted between the driving gear 36 and the driven gear 8, so as to achieve better response to the influence of oil level fluctuation and improve the detection accuracy; the present invention has the advantages of reasonable structure, multi-range adjustable oil level detection, effective avoidance of oil level fluctuation influence, and improved detection accuracy.

[0042] Example 2

[0043] like Figure 8 As shown, the low-voltage transformer oil online detection method adopts the low-voltage transformer oil measuring device as described above to be connected with the tubular oil level gauge, and realizes the low-voltage transformer oil level online detection based on the oil level video detection algorithm. The method comprises the following steps:

[0044] Step 1: Obtain the transformer oil level video under cloudy conditions;

[0045] Step 2: Perform image denoising preprocessing on the acquired oil level video, and then extract the oil level video image features through image enhancement algorithm to detect the oil level height;

[0046] Step 3: Analyze the oil level change trend. If the oil level analysis result is higher than the first limit and lower than the second limit, an alarm signal is given; if it is lower than the first limit, it indicates that a serious fault has occurred in the transformer.

[0047] In this embodiment, ① transformer oil level image denoising preprocessing: the present invention uses bilateral filtering to perform main transformer oil level image denoising preprocessing under cloudy conditions, namely: In the formula, are regularization factor, spatial domain weight, and pixel range domain grayscale weight respectively; σ s , σ r are spatial domain parameters and grayscale domain parameters, respectively. The former represents the spatial extension of the filter kernel, and the latter represents the minimum gradient intensity of the edge; BF[I] P is the output result of bilateral filtering; I q I represents the input image; p represents the output image; p represents the spatial position of the input image pixel; q represents the spatial position of the output image pixel.

[0048] The definition of formula (1) can be decomposed into a filter function determined by the pixel spatial distance and a filter function determined by the pixel color value; the effect of bilateral filtering denoising mainly depends on σ s , σ r , through multiple experiments, bilateral filtering in σ s =5,σ r =1, the preprocessing effect of the main transformer oil level image under cloudy conditions is the best.

[0049] ② Transformer oil level image enhancement: The present invention uses PCHE as the main transformer oil level image enhancement algorithm, and its basic principle is as follows: The probability of each pixel is: In the formula, l, n j , n are the gray value of the pixel, the number of pixels with gray value l, and the total number of pixels respectively; the maximum probability P of the known gray value l dfmax , minimum probability P dfmin When , we can get the gray value improvement probability after parameter adjustment, that is: Then, the cumulative probability distribution of the improved gray value l is: Therefore, the enhancement value of each pixel after parameter adjustment is: Where γ = 1-C dfnew (l)(6).

[0050] The enhancement effects and running time of the three enhancement algorithms are shown in Table 1. The enhancement error is calculated by comparing the pixel-level error between the oil level image after enhancement and the original image. The images are generally grouped in groups of 10 and the average is taken.

[0051] Table 1 Comparison of enhancement effects of 3 algorithms

[0052]

[0053] The PCHE enhanced algorithm can not only meet the requirements of computational efficiency, but also take into account image adaptive adjustment. Therefore, the PCHE algorithm is suitable for on-site real-time detection of transformer oil level.

[0054] ③ Transformer oil level feature extraction and detection: 1) Oil level area feature extraction: The main transformer oil level feature extraction is to extract the target area and its feature value concentrated in the gray value of the oil level image after being processed by the enhancement algorithm. The present invention uses color space segmentation (see formula (7)) to extract the target area after oil level enhancement. The color segmentation technology converts the RGB color of the oil level enhancement image into the HSV color space represented by hue (h), saturation (s), and brightness (v). The basic principle is: In the formula, H out is the binary pixel value; h1, s1, and v1 represent the thresholds of hue, saturation, and brightness, respectively. The output result is a binary image.

[0055] 2) Oil level detection: After obtaining the characteristic image of the oil level area through color segmentation, the number of pixels in the oil area N can be obtained by calculating the attributes of the connected area. l , then, when the total number of pixels in the oil level area is known, the oil level height ratio of the oil area can be calculated as: The actual oil level ratio h0 can be obtained by the actual oil level height H0 and the oil level standard height H, that is: Then, the average error E is: In the formula, M represents the number of pixels extracted in the oil area. The gray threshold segmentation is compared with the HSV segmentation, and the results are shown in Table 2.

[0056] Table 2 Comparison between grayscale threshold segmentation and HSV segmentation

[0057]

[0058] HSV segmentation and grayscale threshold segmentation have similar control accuracy, but HSV segmentation takes less time. Therefore, the HSV segmentation algorithm is suitable for real-time detection of transformer oil level on site.

[0059] The invention discloses an online detection method for low-voltage transformer oil. In use, the invention uses video technology to obtain a real-time image of the transformer oil level, adopts a bilateral filter to perform denoising preprocessing on the real-time video image of the transformer oil level, effectively filters out image noise, and retains image edge information; adopts a parameter correction histogram equalization algorithm to perform image enhancement processing on the denoised oil level video image, which can both enhance the visual effect and meet the calculation efficiency; adopts a color space segmentation algorithm to extract the target features of the oil area of ​​the enhanced image, and analyzes the transformer oil level change trend in real time by calculating the oil level ratio, and detects and analyzes the transformer oil level change in real time; the oil level enhancement image error of the method of the invention reaches the pixel level, and has real-time calculation efficiency; the invention has the advantages of reasonable structure, multi-range adjustable oil level detection, effective avoidance of the influence of oil level fluctuation, and improved detection accuracy.

Claims

1. A low voltage transformer oil measuring device, comprising a housing and a range change adjustment assembly, characterized in that: The shell is a rectangular box structure with an opening on the left side and a main bracket is installed at the opening on the left side. A spring-loaded belt is arranged on the left side of the main bracket, a float is connected below the spring-loaded belt, and the float sleeve is installed inside the jacket tube; a range change adjustment component is arranged inside the shell, the range change adjustment component is connected to the inner wall of the shell through a bearing seat, and a driven gear is connected to the top of the range change adjustment component; a "Z"-shaped moving frame is arranged on the left side of the main bracket, a sensor is installed above the moving frame, and the sensor is connected to the driven gear through a rotating shaft; the sensor is connected to the tubular oil level gauge of the transformer.

2. The low voltage transformer oil measuring device according to claim 1, characterized in that: The main support includes a support plate of an "Ω"-shaped structure, and longitudinal openings are opened on both upper and lower sides of the support plate; the support plate is movably connected to the rotating shaft through the upper longitudinal opening and is connected to the spring-loaded belt through the lower longitudinal opening.

3. The low voltage transformer oil measuring device according to claim 2, characterized in that: A convex rib is arranged on the outside of the rotating shaft along the axial direction, and a sleeve for connecting the driven gear is arranged on the outside of the rotating shaft. A groove is arranged inside the sleeve, and the sleeve cooperates with the convex rib through the groove to realize the movement of the sleeve along the axial direction of the rotating shaft, and the sleeve can drive the rotating shaft to rotate.

4. The low voltage transformer oil measuring device according to claim 3, characterized in that: The spring loaded belt comprises a U-shaped opening frame arranged on one side below the main support, a spring winding belt assembly is arranged inside the U-shaped opening frame, a pull belt is wrapped around the outside of the spring winding belt assembly, the pull belt is connected to the float through a connecting buckle, the spring winding belt assembly is connected to the main support through a nut, a driving gear is connected to the right side of the spring winding belt assembly through the nut shaft, and the driving gear is dynamically connected to the range change adjustment assembly.

5. The low voltage transformer oil measuring device according to claim 4, characterized in that: The jacket pipe comprises a hollow pipe with a hexagonal structure, and a plurality of through holes are arranged on the outer circumference of the hollow pipe from top to bottom; the float is a hexagonal structure matching the hollow pipe.

6. The low voltage transformer oil measuring device according to claim 4, characterized in that: The range change adjustment component includes a central shaft connected to the bearing seat, and a plurality of gear sets arranged vertically are arranged in sequence and spaced apart on the central shaft. Adjacent gear sets are centrally symmetrical with each other, and the gear sets include large gears and small gears that mesh with each other.

7. The low voltage transformer oil measuring device according to claim 1, characterized in that: The middle part of the mobile frame is connected to the main support through a lifting assembly, and the free end of the lower end of the mobile frame is located inside the limiting guide seat; a polished rod is arranged above the inside of the shell, a fork assembly is sleeved outside the polished rod, and a lateral moving device is arranged above the fork assembly.

8. The low voltage transformer oil measuring device according to claim 7, characterized in that: The lifting assembly includes an upper plate connected to the main support and a lower waist-shaped orifice plate connected to the movable frame, a slide groove is arranged inside the left side of the upper plate, a group of first rollers are arranged inside the slide groove, the first rollers are mounted on the movable plate, and a hydraulic device is arranged on the right side of the movable plate; the upper plate and the lower waist-shaped orifice plate are connected by a first connecting rod and a second connecting rod that are cross-hinged with each other, one end of the first connecting rod is hinged to the movable plate, and the other end is connected to the lower waist-shaped orifice plate through the second roller, one end of the second connecting rod is hinged to the upper plate, and the other end is connected to the lower waist-shaped orifice plate through the second roller.

9. The low voltage transformer oil measuring device according to claim 7, characterized in that: The fork assembly includes a sliding sleeve that is slidably connected to the bare rod, a connecting seat connected to a lateral moving device is arranged above the sliding sleeve, and a fork is arranged below the sliding sleeve; the lateral moving device is a gear rack matching assembly, a screw and sleeve matching assembly, a hydraulic rod assembly, a telescopic rod assembly and other structures that can achieve lateral movement.

10. A method for online detection of low-voltage transformer oil, comprising: connecting the low-voltage transformer oil measuring device according to any one of claims 1 to 9 with a tubular oil level gauge, and realizing online detection of the low-voltage transformer oil level based on an oil level video detection algorithm, wherein: The method comprises the following steps: Step 1: Obtain the transformer oil level video under cloudy conditions; Step 2: Perform image denoising preprocessing on the acquired oil level video, and then extract the oil level video image features through image enhancement algorithm to detect the oil level height; Step 3: Analyze the oil level change trend. If the oil level analysis result is higher than the first limit and lower than the second limit, an alarm signal is given; if it is lower than the first limit, it indicates that a serious fault has occurred in the transformer.

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