Oil level meter, transformer and method for calculating transformer oil level value

Abstract

The application provides an oil level gauge, a transformer and a method for calculating the oil level value of the transformer. The oil level gauge comprises a shell and a float assembly, a transmission assembly, a measuring module and a calculating module. The floating part of the float assembly can move with the change of the oil surface. The floating part comprises an engaging part. The transmission assembly comprises a driven part which is engaged with the engaging part. The engaging part can drive the driven part of the transmission assembly to rotate in response to the movement of the floating part in the vertical direction. The displacement measuring part of the measuring module is used to detect the actual displacement of the floating part in the vertical direction. The angle measuring part is used to detect the actual rotation angle of the driven part. When there is a large wear between the engaging part and the driven part, the calculating module can compensate for the transmission ratio drift caused by the wear through compensation calculation, and then cause the problem of inaccurate calculation of the oil level value. In the present scheme, the current oil level value is determined by calculating the theoretical rotation angle of the engaged part, the current rotation angle of the driven part after displacement compensation and other parameters.

Description

Technical Field

[0001] This invention belongs to the field of oil level detection technology, and specifically relates to an oil level gauge, a transformer, and a method for calculating the oil level value of a transformer. Background Technology

[0002] Transformers are core equipment in power systems used to change voltage levels. They are widely used in power transmission, industrial production, and daily life. Their core function is to raise or lower voltage to meet the needs of different scenarios.

[0003] Transformers are classified into various types according to their cooling methods, among which oil-immersed transformers are a common type. In oil-immersed transformers, insulating oil serves as the cooling medium, and heat is transferred to the radiator through natural convection or forced circulation of the oil. The oil level gauge is a crucial monitoring device in oil-immersed transformers, used to detect the insulating oil level in real time and prevent equipment failures caused by abnormal oil levels.

[0004] Traditional mechanical oil level gauges in the prior art convert the linear motion of a float into pointer rotation through a gear and rack mechanism. For example, patent CN221725332U discloses a novel transformer oil level gauge that converts the linear motion of the float into the rotational motion of the gears via a rack and gear meshing mechanism, and then obtains the level of insulating oil by reading the scale. However, after long-term operation, this type of oil level gauge will experience wear on the meshing surfaces of the gear and rack (especially at low temperatures where grease hardens and accelerates wear), leading to inaccurate measurement of the actual oil level. Summary of the Invention

[0005] The purpose of this invention is to solve the problem that wear of the meshing tooth surfaces of oil level gauges occurs after long-term operation, leading to inaccurate measurement of actual oil level values.

[0006] To address the aforementioned technical problems, embodiments of the present invention disclose an oil level gauge, comprising a housing and a float assembly, a transmission assembly, a measuring module, and a calculating module mounted on the housing. The float assembly includes a floating component that can move vertically in response to changes in the oil surface level, and the floating component includes an engaging portion. The transmission assembly includes a driven portion that is throttledly connected to the engaging portion; in response to the vertical movement of the floating component, the engaging portion can drive the driven portion to rotate. The measuring module includes a displacement measuring component and an angle measuring component. The displacement measuring component detects the actual displacement of the floating component in the vertical direction, and the angle measuring component is mounted on the housing and connected to the driven portion; the angle measuring component detects the actual rotation angle of the driven portion. The calculation module is communicatively connected to both the displacement measurement component and the angle measurement component. It receives the actual displacement of the floating component from the displacement measurement component and the actual rotation angle of the driven component from the angle measurement component. Based on the actual displacement of the floating component, it determines the theoretical rotation angle of the driven component. Then, based on the absolute value of the difference between the actual and theoretical rotation angles, it determines the current displacement of the floating component, the current rotation angle of the driven component, and the current oil level of the transformer. Specifically, if the absolute value of the difference between the actual and theoretical rotation angles is less than a rotation angle threshold, the current displacement of the floating component is its actual displacement. If the absolute value of the difference is greater than or equal to the rotation angle threshold, the displacement compensation amount of the floating component is determined based on the difference between the actual and theoretical rotation angles and the usage time of the oil level gauge. The current displacement of the floating component is the sum of its actual displacement and the displacement compensation amount.

[0007] Using the above technical solution, the oil level gauge is used in oil-immersed transformers. The float assembly, transmission assembly, measurement module, and calculation module of the oil level gauge are all installed on or inside the housing, so that the entire oil level gauge is immersed in oil. The housing is connected to the outside, and the oil position inside the housing is always the same as the oil position outside the housing. The floating part of the float assembly changes synchronously in the vertical direction with the position of the oil surface, so the displacement change of the floating part can directly reflect the height change of the oil surface. The linear motion of the floating part in the vertical direction is converted into the rotational motion of the driven part by the meshing of the driven part and the meshing part of the transmission assembly. The calculation module uses a pre-stored mathematical model between the rotation angle of the driven part and the current oil level value, and substitutes the current rotation angle of the driven part (determined by the current displacement of the floating part) to obtain the current oil level value.

[0008] However, due to the increased operating time of the oil level gauge and the hardening of grease at low temperatures, wear will occur between the meshing surface and the driven surface. Therefore, it is necessary to use a calculation module to determine whether there is significant wear between the meshing part and the driven part, and to perform wear compensation calculations when significant wear occurs, in order to calculate an accurate current oil level value. Thus, the displacement measuring component of the measurement module measures the actual displacement change of the floating component with the oil surface, and the angle measuring component of the measurement module measures the actual rotation angle of the driven part under the drive of the meshing part. In the calculation module, the theoretical rotation angle of the driven part can be determined based on the actual displacement of the floating component. Furthermore, the presence of wear error in the oil level gauge can be determined based on the actual rotation angle and the theoretical rotation angle. When significant wear exists between the meshing part and the driven part, the displacement compensation amount of the floating component can be determined based on the difference between the actual and theoretical rotation angles, as well as the usage time of the oil level gauge. The current displacement of the floating component is the sum of its actual displacement and the displacement compensation amount. In other words, the current displacement of the floating component is obtained through compensation calculation. Then, based on the current displacement and the transmission ratio between the meshing and driven parts, the current rotation angle of the driven part can be determined. Finally, the current rotation angle of the driven part is substituted into the mathematical model of the rotation angle of the driven part and the current oil level value pre-stored in the calculation module to determine the current oil level value of the transformer. Furthermore, the calculation module also has data storage and remote signal transmission functions. It can store the measured and calculated data for easy retrieval by maintenance personnel; it can also remotely transmit the calculated current oil level value, enabling remote monitoring of the oil level value and maintenance of related equipment.

[0009] According to another specific embodiment of the present invention, an oil level gauge is disclosed, wherein the meshing part is a rack extending in a vertical direction, the driven part is a connecting gear, the connecting gear is rotatably supported on the housing by an angle measuring component, when the rack moves in a vertical direction, the connecting gear rotates under the drive of the rack, and the displacement measuring component is used to collect the actual displacement of the rack and send it to the calculation module.

[0010] Using the above technical solution, when the rack extends vertically, it can move vertically with the oil surface and maintain transmission with the connecting gear during the movement. The linear movement of the rack is converted into the rotational motion of the connecting gear. The calculation module pre-stores the correspondence between the rotation angle of the connecting gear and the oil level value. The calculation module can then determine the current rotation angle of the connecting gear based on parameters such as the actual displacement of the rack, the actual rotation angle of the connecting gear, and the theoretical rotation angle of the connecting gear, and thus determine the current oil level value of the transformer.

[0011] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a transformer, including an oil tank and an oil level gauge disclosed in the above embodiment; wherein, the oil tank is filled with transformer oil, and the oil level gauge is used to be immersed in the inside of the oil tank.

[0012] Using the above technical solution, the transformer can perform oil level compensation under wear conditions to obtain an accurate oil level value. It can also achieve remote communication. When the transformer is set up in unattended substations, at sea, in deserts, or other locations where it is inconvenient for maintenance personnel to directly inspect it, it can remotely transmit measurement data to support remote monitoring and maintenance.

[0013] According to another specific embodiment of the present invention, an embodiment of the present invention discloses a method for calculating the transformer oil level, which uses an oil level gauge for calculation. The calculation method includes:

[0014] S1. Obtain the actual vertical displacement of the floating component and the actual rotation angle of the driven part. Determine the theoretical rotation angle of the driven part based on the actual vertical displacement of the floating component, and determine the current displacement of the floating component based on the absolute value of the difference between the actual and theoretical rotation angles. If the absolute value of the difference between the actual and theoretical rotation angles is less than the rotation angle threshold, the current displacement of the floating component is the actual displacement of the floating component. If the absolute value of the difference between the actual and theoretical rotation angles is greater than or equal to the rotation angle threshold, determine the displacement compensation amount of the floating component based on the difference between the actual and theoretical rotation angles and the usage time of the oil level gauge. The current displacement of the floating component is the sum of the actual displacement of the floating component and the displacement compensation amount. S2. Determine the current rotation angle of the driven part based on the current displacement of the floating component. S3. Determine the current oil level value of the transformer based on the current rotation angle of the driven part.

[0015] In summary, this invention provides an oil level gauge, a transformer, and a method for calculating the transformer oil level. The oil level gauge includes a housing and a float assembly, a transmission assembly, a measuring module, and a calculation module mounted on the housing. The displacement change of the floating component of the float assembly directly reflects the height change of the oil surface. By interlocking the driven part of the transmission assembly with the meshing part of the floating component, the linear motion of the floating component in the vertical direction is converted into the rotational motion of the driven part. The calculation module uses a pre-stored mathematical model between the rotation angle of the driven part and the current oil level value, and substitutes the current rotation angle of the driven part (determined based on the current displacement of the floating component) to obtain the current oil level value. When significant wear exists between the meshing part and the driven part, the calculation module can calculate the current displacement of the floating component. Based on this current displacement and the transmission ratio between the meshing and driven parts, the current rotation angle of the driven part can be determined. Then, by substituting this current rotation angle into a pre-stored mathematical model of the rotation angle and current oil level in the calculation module, the current oil level of the transformer can be determined, thus correcting mechanical wear errors down to the 0.01mm level. Furthermore, the calculation module also has data storage and remote signal transmission functions. It can store measured and calculated data for maintenance personnel to retrieve data for fault tracing; it can also remotely transmit the calculated current oil level value, enabling remote monitoring of the oil level and maintenance of related equipment. Attached Figure Description

[0016] Figure 1a This is a schematic diagram of one overall structure of the oil level gauge provided in Embodiment 1 of the present invention;

[0017] Figure 1b This is a schematic diagram of another overall structure of the oil level gauge provided in Embodiment 1 of the present invention;

[0018] Figure 1c This is a schematic diagram of another overall structure of the oil level gauge provided in Embodiment 1 of the present invention;

[0019] Figure 2 This is a flowchart of the oil level value calculation method of the oil level gauge provided in Embodiment 1 of the present invention;

[0020] Figure 3 This is a structural block diagram of the measurement module and calculation module of the oil level gauge provided in Embodiment 1 of the present invention;

[0021] Figure 4 This is a top view of the oil level gauge provided in Embodiment 1 of the present invention;

[0022] Figure 5 for Figure 4 A cross-sectional view along the AA direction.

[0023] Explanation of reference numerals in the attached figures:

[0024] 1. Float assembly; 10. Floating component; 101. Rack; 102. Sleeve; 103. Float; 104. Connecting rod; 11. Rod-shaped guide component;

[0025] 2. Transmission assembly; 20. First gear; 21. Connecting shaft; 22. Second gear; 23. Connecting gear;

[0026] 3. Measurement module; 30. Angle measurement component;

[0027] 4. Calculation module; 40. Processing unit; 41. Memory; 42. Communication unit;

[0028] 5. Shell. Detailed Implementation

[0029] Transformers are core equipment in power systems used to change voltage levels. They are widely used in power transmission, industrial production, and daily life. Their core function is to raise or lower voltage to meet the needs of different scenarios.

[0030] Transformers are classified into various types according to their cooling methods, among which oil-immersed transformers are a common type. Oil-immersed transformers use insulating oil as the cooling medium inside, and heat is transferred to the radiator through natural convection or forced circulation of the oil.

[0031] However, transformers located in remote areas, such as unmanned substations, offshore wind power transformers, and rail transit traction transformers, are not easily monitored in real time to determine their oil levels. Since oil level is a key factor in determining whether equipment malfunctions, real-time monitoring of the insulating oil level can prevent equipment failures caused by abnormal oil levels. In oil-immersed transformers, the oil level gauge is a crucial monitoring device used to detect the insulating oil level in real time and prevent equipment failures caused by abnormal oil levels.

[0032] Traditional mechanical oil level gauges convert the linear motion of a float into pointer rotation using a gear-rack mechanism. However, after long-term operation, wear occurs on the meshing surfaces of the gears and rack (especially at low temperatures where grease hardening exacerbates wear), causing transmission ratio drift and resulting in inaccurate oil level measurements. The error can reach ±0.1 mm / year, requiring frequent manual calibration. Furthermore, under extreme temperature differences of -40℃ to 120℃, the difference in thermal expansion coefficients between the metal gears and the housing (e.g., Δα≈11×10⁻⁶ for steel and aluminum alloys) is significant. -6 / ℃) can easily lead to changes in meshing clearance. Conventional grease will solidify at low temperatures (pour point > -20℃) and its viscosity will decrease at high temperatures (evaporation rate > 5% at 120℃).

[0033] Therefore, the core mechanical structure of existing oil level gauges is covered by the casing and cannot be observed. Moreover, most transformers are located in relatively remote fields, making manual operation and calibration inconvenient. Long-term operation or low-temperature operation can cause severe mechanical wear, leading to inaccurate measurement of actual oil level values.

[0034] To address the aforementioned problems, this invention provides an oil level gauge that can determine whether mechanical wear of the meshing teeth has occurred within the gauge. When the mechanical wear of the meshing teeth is severe, the gauge performs transmission ratio compensation to correct the transmission ratio drift caused by the wear, thereby accurately calculating the current oil level value. This allows for accurate calculation of the current oil level value even when the internal structure of the oil level gauge cannot be observed or when the transformer is located in a remote area and cannot be monitored in real time.

[0035] 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.

[0036] Example 1

[0037] The oil level gauge provided by this invention is used in oil-immersed transformers, and the entire oil level gauge is immersed in oil. Figures 1a-1c As shown, it includes a housing 5 (for ease of showing the structure inside the housing 5, Figure 1c Only the side wall and bottom of the housing 5 are shown in the figure. The inside of the housing 5 is connected to the outside of the housing 5. The oil position inside the housing 5 is always the same as the oil position outside the housing 5. The float assembly 1, transmission assembly 2, measurement module 3 and calculation module 4 of the oil level gauge are all installed on or inside the housing 5. The floating part 10 of the float assembly 1 inside the housing 5 changes synchronously in the vertical direction with the position of the oil surface. Therefore, the displacement change of the floating part 10 can directly reflect the height change of the oil surface.

[0038] The floating component 10 includes an engaging part, and the transmission assembly 2 includes a driven part that is driven by the engaging part. The driven part is the output end of the transmission assembly 2, which is also the actual object being measured when the angle measuring component 30, described later, measures the rotation angle. When the floating component 10 moves vertically with the oil surface, the engaging part can drive the driven part to rotate, converting the linear movement of the floating component 10 in the vertical direction into the rotational motion of the driven part. By converting the minute linear displacement change of the floating component 10 into the angular change of the driven part, a small linear displacement change can be converted into a large angular value change by reasonably setting the transmission ratio between the engaging part and the driven part. Thus, the oil level gauge can more sensitively and accurately reflect oil level changes through the angular value.

[0039] The actual parameters measured by the measurement module 3 are used to determine whether wear has occurred and to calculate the transmission ratio compensation. The displacement measuring component is used to detect the actual displacement of the floating component 10 in the vertical direction. The angle measuring component 30 is installed on the housing 5 and connected to the driven part. The angle measuring component 30 is used to detect the actual rotation angle of the driven part.

[0040] The calculation module 4 is used to acquire the measured parameters and calculate the theoretical rotation angle of the driven part, determine whether there is wear between the driven part and the meshing part, calculate the displacement compensation of the floating part 10, determine the current displacement of the floating part 10, determine the current rotation angle of the driven part based on the current displacement, and determine the current oil level value of the transformer based on the current rotation angle of the driven part.

[0041] To facilitate understanding of the specific structure and working principle of the oil level gauge, a detailed introduction to the oil level gauge is provided below:

[0042] like Figures 1a-1c As shown, the housing 5 provides rigid support for the float assembly 1, the transmission assembly 2, the measurement module 3, and the calculation module 4. The housing 5 is a basic component of the oil level gauge and can be a cube with a cavity or other irregular three-dimensional structure. No specific restrictions are made here, and those skilled in the art can set it as needed.

[0043] The float assembly 1 is the core component of the oil level gauge used to detect changes in oil level. By setting the floating component 10, when the oil level changes, the floating component 10 can move with the oil under the action of buoyancy. The volume and density of the floating component 10 can be reasonably set by those skilled in the art based on the density of the oil. The floating component 10 can float entirely on the oil surface, or it can float partially on the oil surface while the other part is immersed in the oil. For example, a float ball can be set at one end of the floating component 10, floating on the oil surface and pulling the other part of the floating component 10 to move with the float ball. In order to ensure that the actual vertical displacement of the floating component 10 is the change in the oil level, a guide component, such as a guide rod, can be connected to the floating component 10 to guide the floating component 10 to move only in a vertical straight line.

[0044] The meshing part (e.g., rack 101) and the driven part (e.g., connecting gear 23) can be connected by meshing with each other to achieve a transmission connection. For example, the meshing part of the floating member 10 can be either rack 101 or gear. When the meshing part is rack 101, the meshing teeth on rack 101 are arranged in the vertical direction. The driven part meshing with it can be a gear with its axis parallel to the vertical direction or a gear with its axis perpendicular to the vertical direction. When the axis of the gear that is the driven part is parallel to the vertical direction, rack 101 and gear mesh with each other through helical teeth. When the meshing part is gear, the axis of the gear can be parallel to the vertical direction or perpendicular to the vertical direction. The driven part meshing with it can be a gear with its axis parallel to the vertical direction or a gear with its axis perpendicular to the vertical direction. Setting the meshing teeth of the meshing part of the two parts to be helical teeth or straight teeth according to the axial direction of the two parts is a conventional means in the art and will not be described in detail here.

[0045] The meshing part (e.g., rack 101) and the driven part (e.g., connecting gear 23) can also be connected by an intermediate gear transmission structure. For example, an intermediate gear can be provided between the meshing part and the driven part, and the intermediate gear meshes with both the meshing part and the driven part, thereby achieving a transmission connection between the meshing part and the driven part; or two coaxially connected intermediate gears can be provided between the meshing part and the driven part, with one intermediate gear meshing with the meshing part and the other intermediate gear meshing with the driven part, thereby achieving a transmission connection between the meshing part and the driven part; of course, more intermediate gears can be provided between the meshing part and the driven part.

[0046] It should be noted that the meshing teeth in the transmission assembly 2 are all coated with a diamond-like carbon (DLC) coating. For example, the meshing part, the driven part, and the meshing teeth of the intermediate gear (in the case of an intermediate gear) are all coated with a DLC coating. The diamond-like carbon (DLC) coating is an amorphous carbon-based thin film with excellent comprehensive performance. It has the characteristics of high hardness, low friction, and wear resistance, which can effectively improve the wear resistance of the meshing part and the driven part. Its thickness can be between 1μm and 3μm. In this embodiment, it is preferably 2μm. After coating with a DLC coating, the wear resistance life of the oil level gauge meshing surface provided in this embodiment is increased by 3 times.

[0047] In one specific embodiment of the present invention, such as Figure 1aAs shown, the meshing part is a rack 101 extending vertically, and the driven part is a connecting gear 23, which meshes with each other. An angle measuring component 30 is disposed on one side of the disk surface of the connecting gear 23. The connecting gear 23 is rotatably supported on the housing 5 by the angle measuring component 30. When the axis of the connecting gear 23 is perpendicular to the extending direction of the rack 101, the angle measuring component 30 is connected to the side wall of the housing 5, and the rack 101 and the connecting gear 23 mesh with each other through spur teeth; when the axis of the connecting gear 23 is parallel to the extending direction of the rack 101 (i.e.,...), the angle measuring component 30 is connected to the side wall of the housing 5. Figure 1a (as shown in the diagram), the angle measuring component 30 is fixedly connected to the upper or lower side of the housing 5, and the rack 101 and the connecting gear 23 mesh with each other through helical teeth.

[0048] For ease of understanding, the following text will use the example of the axis of the connecting gear 23 being parallel to the vertical direction.

[0049] Specifically, when the rack 101 moves vertically, the connecting gear 23 rotates relative to the housing 5 under the drive of the rack 101. After measuring the actual displacement of the rack 101 in the vertical direction and the actual rotation angle of the connecting gear 23, the theoretical rotation angle of the connecting gear 23 can be calculated based on the actual displacement of the rack 101 and the pitch circle radius of the connecting gear 23. By comparing the theoretical rotation angle and the actual rotation angle of the connecting gear 23, the wear between the meshing teeth of the connecting gear 23 and the rack 101 is judged (transmission ratio drift judgment). In the case of large wear, the displacement of the rack 101 is compensated (transmission ratio compensation). Then, the current displacement of the rack 101 is determined according to the wear condition, and the current rotation angle of the connecting gear 23 is calculated based on the current displacement of the rack 101 and the pitch circle radius of the connecting gear 23. Finally, the accurate oil level value can be calculated.

[0050] In another specific embodiment of the present invention, such as Figure 1b As shown, when the rack 101 and the connecting gear 23 are indirectly connected by an intermediate gear, the transmission assembly 2 also includes a first gear 20 rotatably supported on the housing 5 via a connecting shaft 21. The rack 101 can mesh with the first gear 20, so that the first gear 20 can rotate relative to the housing 5 around a first axis (the first axis is the axis of the connecting shaft 21) under the drive of the rack 101. The first gear 20 is also connected to the connecting gear 23. When the first gear 20 and the connecting gear 23 are directly meshed, the rack 101 can rotate around the first axis by the first gear 20 in conjunction with the connecting shaft 21, and then the connecting gear 23 can rotate relative to the housing 5 around a second axis, wherein the second axis is parallel to the first axis.

[0051] Specifically, when the rack 101 moves vertically, the connecting gear 23 rotates relative to the housing 5 under the drive of the first gear 20. After measuring the actual vertical displacement of the rack 101 and the actual rotation angle of the connecting gear 23, the theoretical rotation angle of the connecting gear 23 can be calculated based on the actual displacement of the rack 101, the pitch circle radius of the first gear 20, and the transmission ratio between the first gear 20 and the connecting gear 23 (a fixed value pre-stored in the calculation module 4). The transmission assembly 2 is then compared with the theoretical rotation angle of the connecting gear 23. Wear judgment (transmission ratio drift judgment) between meshing teeth (including meshing teeth between the first gear 20 and rack 101 and meshing teeth between the first gear 20 and connecting gear 23) is performed. In the case of large wear, displacement compensation (transmission ratio compensation) of rack 101 is performed. Then, the current displacement of rack 101 is determined according to the wear condition. Based on the current displacement of rack 101, the pitch circle radius of the first gear 20 and the transmission ratio between the first gear 20 and connecting gear 23, the current rotation angle of connecting gear 23 is calculated. Finally, an accurate oil level value can be calculated.

[0052] In another specific embodiment of the present invention, such as Figure 1c As shown, when the rack 101 and the connecting gear 23 are indirectly connected via an intermediate gear, the transmission assembly 2, in addition to the first gear 20, may also include a second gear 22. The second gear 22 is rotatably supported on the housing 5 via the connecting shaft 21. The first gear 20 is fixedly connected to the lower end of the connecting shaft 21, and the second gear 22 is fixedly connected to the upper end of the connecting shaft 21. The second gear 22 meshes with the connecting gear 23. When the rack 101 moves vertically, the first gear 20 can rotate relative to the housing 5 around a first axis (the first axis is the axis of the connecting shaft 21) under the drive of the rack 101. Since the second gear 22 and the first gear 20 are coaxially connected via the connecting shaft 21, the second gear 22 can rotate around the first axis under the drive of the first gear 20, and simultaneously cause the connecting gear 23 to rotate relative to the housing 5 around a second axis.

[0053] Specifically, when the rack 101 moves vertically, the connecting gear 23 rotates relative to the housing 5 under the drive of the second gear 22. After measuring the actual vertical displacement of the rack 101 and the actual rotation angle of the connecting gear 23, the theoretical rotation angle of the connecting gear 23 can be calculated based on the actual displacement of the rack 101, the pitch circle radius of the first gear 20, and the transmission ratio between the second gear 22 and the connecting gear 23 (a fixed value pre-stored in the calculation module 4). The meshing teeth (including the first gear 20) in the transmission assembly 2 are then compared with the theoretical rotation angle of the connecting gear 23. Wear judgment (transmission ratio drift judgment) between the meshing teeth of gear 20 and rack 101 and the meshing teeth of the second gear 22 and connecting gear 23 is performed. In the case of large wear, displacement compensation (transmission ratio compensation) of rack 101 is performed. Then, the current displacement of rack 101 is determined according to the wear condition. Based on the current displacement of rack 101, the pitch circle radius of the first gear 20 and the transmission ratio between the second gear 22 and connecting gear 23, the current rotation angle of connecting gear 23 is calculated. Finally, the accurate oil level value can be calculated. The specific calculation method will be introduced in detail later.

[0054] Understandably, the above method can compensate for mechanical wear between the meshing tooth surfaces in the oil level gauge, thus making the measured oil level more accurate.

[0055] It should be noted that, in order to reduce wear between the meshing teeth, a diamond-like coating can be applied to all meshing tooth surfaces of the oil level gauge to slow down mechanical wear.

[0056] It should also be noted that the angle measuring component 30 can specifically be an angle encoder. The working principle of an angle encoder is mainly to convert the rotation angle into an electrical signal. Common types include photoelectric and magnetoelectric.

[0057] A photoelectric angle encoder mainly consists of a light source, a grating disk, a photodetector, and a signal processing circuit. The grating disk has many concentric rings of light-transmitting and opaque lines, dividing the disk into several equal parts. As the grating disk rotates with the shaft, the light-transmitting and opaque parts alternately block light, and the photodetector converts the changes in light intensity into electrical signals. After processing by the signal processing circuit, it outputs a pulse signal or code signal corresponding to the rotation angle.

[0058] For incremental encoders, a pulse is generated for each graduation mark interval, and the rotation angle can be determined by counting the number of pulses. Simultaneously, two sets of photodetectors are typically used, generating A-phase and B-phase pulse signals with a 90° phase difference; comparing their phase relationship determines the rotation direction. For absolute encoders, each position corresponds to a unique binary code, and the output code signal directly represents the angular position.

[0059] A magneto-electric angle encoder mainly consists of a magnetic ring and Hall elements or magnetoresistive elements. Multiple magnetic poles are distributed on the magnetic ring, and the Hall elements or magnetoresistive elements are installed near the magnetic ring. When the rotating shaft drives the magnetic ring to rotate, the Hall elements or magnetoresistive elements detect the change in magnetic field strength, thereby generating a corresponding electrical signal. Based on the change in the electrical signal, the signal processing circuit converts and calculates the result to obtain the rotation angle information.

[0060] Since the floating component 10 changes vertically with the liquid level, a guiding structure is needed to guide the floating component 10 to move linearly in order to ensure that the displacement of the floating component 10 is always linear. For example... Figures 1a-1c As shown, the float assembly 1 also includes a rod-shaped guide member 11 adapted to and connected to the floating member 10. The rod-shaped guide member 11 is fixed to the housing 5 and extends in the vertical direction. The floating member 10 is slidably connected to the rod-shaped guide member 11 in the vertical direction.

[0061] It should be noted that the floating component 10 and the rod-shaped guide component 11 can slide against each other through a sliding groove and rail, a ball bearing and sliding groove, or a sleeve structure. Specifically, the rod-shaped guide component 11 can be a guide rod, with a groove on the side of the guide rod facing the floating component 10 and a strip-shaped protrusion matching the groove on the corresponding part of the floating component 10. Alternatively, a strip-shaped protrusion can be provided on the side of the guide rod facing the rack 101, with a matching groove on the corresponding part of the floating component 10. When the floating component 10 includes a sleeve 102 in addition to the rack 101, the sleeve 102 is formed on the side of the rack 101 away from the first gear 20, and the sleeve 102 can be sleeved on the outer periphery of the guide rod and slide against the guide rod. In addition, the floating component 10 may also include a float 103, which can float on the surface of the oil. The float 103 can be fixedly connected to the side of the rack 101 away from the first gear 20 by a connecting rod 104, and is spaced apart from the sleeve 102 in the vertical direction. When the oil surface changes displacement, the floating float 103 can drive the rack 101 to move in the vertical direction. The actual displacement of the rack 101 is measured by a displacement measuring component provided on the rack 101. Figures 1a-1c (Not shown in the image) The data is collected and transmitted to the calculation module 4. The displacement measuring component can be specifically set at the bottom, middle, top, or other positions of the rack 101, as long as the displacement measuring component can move vertically with the rack 101 to measure the actual displacement of the rack 101. The displacement measuring component can be, for example, a potentiometer-type displacement sensor, a magnetostrictive displacement sensor, a capacitive displacement sensor, a photoelectric displacement sensor, or an ultrasonic displacement sensor, etc., of different types of displacement sensors.

[0062] The calculation module 4 is communicatively connected to both the displacement measuring component and the angle measuring component 30. The displacement measuring component of the measurement module 3 measures the actual vertical displacement of the floating component 10, and the angle measuring component 30 detects the driven part (see details). Figures 1a-1c After the actual rotation angle of the connecting gear 23), the calculation module 4 receives the actual displacement and actual rotation angle, and can then determine whether mechanical wear has occurred and calculate the current oil level of the transformer.

[0063] It should be noted that the calculation module 4 provided in this embodiment has communication, data processing and data storage functions. Therefore, it can receive real-time parameters collected by the sensor. It also has a mathematical model for calculating the oil level value stored in advance. Therefore, it can realize data processing and store the collected and calculated data.

[0064] The following is based on Figure 1c Taking the oil level gauge structure shown as an example, the specific calculation process of the oil level value is explained as follows: the meshing part is the rack 101, the driven part is the connecting gear 23, and the transmission assembly 2 also includes a first gear 20, a connecting shaft 21, and a second gear 22, as shown below. Figure 2 As shown, the specific calculation process for the oil level value is as follows:

[0065] First, the calculation module 4 obtains the actual displacement of the rack 101 as sent by the displacement measuring component and the actual rotation angle of the connecting gear 23 as sent by the angle measuring component 30.

[0066] Next, the calculation module 4 determines the theoretical rotation angle of the connecting gear 23 based on the actual displacement of the rack 101. Specifically, the theoretical rotation angle of the connecting gear 23 can be calculated according to the following formula (1):

[0067]

[0068] Wherein, θ is the theoretical rotation angle of the connecting gear 23 (in degrees), L is the actual displacement of the rack 101, r is the pitch circle radius of the first gear 20 (the pitch circle is a size reference chosen for the convenience of gear design and manufacturing; the specific calculation formula for the pitch circle radius is number of teeth × module / 2; the number of teeth and module of the first gear 20 can be obtained in advance and stored in the calculation module 4, or the value of the pitch circle radius of the first gear 20 can be directly stored in the calculation module 4), and i is the transmission ratio between the second gear 22 and the connecting gear 23, which can be understood as the ratio of the number of teeth of the connecting gear 23 to the number of teeth of the second gear 22, i.e., i is the number of teeth of the connecting gear 23 / the number of teeth of the second gear 22. It should be noted that the number of teeth of the connecting gear 23 and the number of teeth of the second gear 22 are values ​​that can be obtained in advance and stored in the calculation module 4 based on the structural parameters of the gears, and the ratio between the two can also be pre-stored in the calculation module 4.

[0069] Furthermore, by comparing the absolute value of the difference between the actual rotation angle and the theoretical rotation angle of the connecting gear 23 with the rotation angle threshold according to the following formula (2), it can be determined whether wear has occurred between the meshing surfaces of the rack 101 and the first gear 20, and between the meshing surfaces of the second gear 22 and the connecting gear 23. Thus, different methods can be used to determine the current displacement of the rack 101 under different wear conditions:

[0070] |θ-θ0|≥a (2)

[0071] Where θ is the theoretical rotation angle of the connecting gear 23, θ0 is the actual rotation angle of the connecting gear 23, and a is a preset rotation angle threshold, which can be set to 0.1°.

[0072] The specific method for determining wear and tear is as follows:

[0073] When the absolute value of the difference between the theoretical angle and the actual angle is less than the preset angle threshold a, it indicates that the error between the two is small, no wear has occurred or the wear is not serious, and it does not affect the final oil level calculation. The actual displacement of the floating component 10 can be directly used as the current displacement. Since the mathematical model for calculating the current oil level stored in the calculation module 4 is the correspondence between the current angle of the driven part and the current oil level, it is necessary to convert the current displacement of the floating component 10 into the current angle of the driven part before calculating the current oil level. The current displacement is converted into the current angle by the following formula (3):

[0074]

[0075] Where θ' is the current rotation angle of the connecting gear 23, r is the pitch circle radius of the first gear 20 (the specific calculation formula for the pitch circle radius is the number of teeth × module / 2), i can be understood as the ratio of the number of teeth of the connecting gear 23 to the number of teeth of the second gear 22, that is, i is the number of teeth of the connecting gear 23 / the number of teeth of the second gear 22, and l is the current displacement.

[0076] The current oil level is determined according to the following formula (4):

[0077] H=θ'r+h (4)

[0078] Where H is the current oil level, h is the initial oil level, θ' is the current rotation angle of the connecting gear 23, and r is the pitch circle radius of the first gear 20 (the specific calculation formula for the pitch circle radius is number of teeth × module / 2).

[0079] When the absolute value of the difference between the actual rotation angle and the theoretical rotation angle is greater than or equal to the preset rotation angle threshold a, it indicates that the error between the two is large and severe wear has occurred between the meshing teeth. In this case, the calculation result of the oil level value will be inaccurate. Therefore, compensation calculation is required to make up for the error caused by the wear of the meshing surface. The compensation is performed by the following formula (5):

[0080] ΔL=k(θ-θ0)+bT (5)

[0081] Wherein, ΔL is the displacement compensation amount of rack 101, k is the conversion coefficient between the rotation angle difference and the displacement obtained based on actual experience, b is the dynamic compensation coefficient (which is related to factors such as materials, site environment, and temperature, and is obtained through experience accumulation), and T is the usage time of the oil level gauge (the usage time can be collected by a timer, and the unit of time is years).

[0082] The current displacement of rack 101 after correction and compensation is determined according to the following formula (6):

[0083] l=ΔL+L (6)

[0084] Where l is the current displacement, ΔL is the displacement compensation amount of rack 101, and L is the actual displacement of rack 101.

[0085] Since the mathematical model for calculating the current oil level stored in the calculation module 4 is the correspondence between the current rotation angle of the driven part (connecting gear 23) and the current oil level, it is necessary to convert the current displacement into the current rotation angle of the driven part (connecting gear 23) before calculating the current oil level. The conversion process of the current displacement into the current rotation angle is described in the above formulas (3) and (4), thereby determining the current oil level.

[0086] In addition, the calculation module 4 also has the functions of data storage and remote signal transmission. It can store the measured and calculated data, which is convenient for operation and maintenance personnel to obtain for subsequent fault tracking. It can also remotely transmit the calculated current oil level value to realize remote monitoring of the oil level value and maintenance of related equipment.

[0087] In one specific embodiment of the present invention, such as Figure 3 and Figure 5 As shown, the computing module 4 includes a processing unit 40, a memory 41, and a communication unit 42.

[0088] Specifically, the communication unit 42 receives the actual displacement of the floating component 10 from the displacement measuring component and the actual rotation angle of the driven part from the angle measuring component 30, and sends them to the processing unit 40. The communication unit 42 can be an RS485 interface, communicating via the Modbus protocol, supporting remote calibration command reception and data upload. The processing unit 40 determines the theoretical rotation angle of the driven part based on the actual displacement of the floating component 10, and determines the current oil level of the transformer based on the actual and theoretical rotation angles. The memory 41 stores the actual and theoretical rotation angles of the driven part, the displacement compensation amount of the floating component 10, and the date the displacement compensation amount was recorded. The memory 41 can be an electrically erasable programmable read-only memory (EEPROM), which retains data even after power failure and can store 10 years of calibration records for easy fault tracing.

[0089] Example 2

[0090] The present invention also provides a transformer, including an oil tank and an oil level gauge as provided in Embodiment 1. The oil tank is filled with transformer oil, and the oil level gauge is used to immerse itself inside the oil tank. The transformer equipped with this oil level gauge can realize wear identification and self-calibration compensation, and can accurately calculate the current oil level value of the transformer.

[0091] This oil level gauge is suitable for transformers in unattended substations, supports remote calibration, and reduces the risk of maintenance personnel working at heights; it is also suitable for offshore wind power transformers, adapts to high salt spray and high humidity environments, and has a corrosion-resistant coating with a lifespan of up to 15 years; it is also suitable for rail transit traction transformers, with an anti-vibration design (amplitude ≤5g) to ensure stable readings when high-speed trains are running.

[0092] Example 3

[0093] This embodiment provides a method for calculating the oil level of a transformer, used to calculate the oil level of the oil level gauge provided in Embodiment 1. This method can accurately identify the wear of the meshing tooth surfaces in the oil level gauge and perform self-calibration compensation when the wear is severe. By calculating the displacement compensation of the meshing part (specifically, the rack 101 in Figure 1) and the transmission ratio drift error between the meshing surfaces in the oil level gauge (for example, the meshing surface between the rack 101 and the first gear 20, and the meshing surface between the second gear 22 and the connecting gear 23 in Figure 1), the current oil level of the transformer can be accurately calculated.

[0094] The calculation method includes: S1, obtaining the actual displacement of the floating component 10 in the vertical direction and the actual rotation angle of the driven part, determining the theoretical rotation angle of the driven part based on the actual displacement of the floating component 10 in the vertical direction, and determining the current displacement of the floating component based on the absolute value of the difference between the actual rotation angle and the theoretical rotation angle.

[0095] Wherein, if the absolute value of the difference between the actual rotation angle and the theoretical rotation angle is less than the rotation angle threshold, then the current displacement of the floating component 10 is the actual displacement of the floating component 10; if the absolute value of the difference between the actual rotation angle and the theoretical rotation angle is greater than or equal to the rotation angle threshold, then the displacement compensation amount of the floating component 10 is determined according to the difference between the actual rotation angle and the theoretical rotation angle and the usage time of the oil level gauge, and the current displacement of the floating component 10 is the sum of the actual displacement of the floating component 10 and the displacement compensation amount.

[0096] S2. Determine the current rotation angle of the driven part based on the current displacement of the floating part 10.

[0097] S3. Determine the current oil level of the transformer based on the current rotation angle of the driven part.

[0098] It should be noted that this calculation method can be obtained automatically by a computer program, that is, the steps performed by calculation module 4.

[0099] The calculation method is explained below using the oil level gauge in Example 1, which includes a rack 101, a connecting gear 23, a first gear 20, and a second gear 22:

[0100] S1. Obtain the actual displacement of the floating component 10 in the vertical direction and the actual rotation angle of the driven part, and determine the theoretical rotation angle of the driven part based on the actual displacement of the floating component 10 in the vertical direction.

[0101] Specifically, firstly, the calculation module 4 receives the actual displacement of the rack 101 from the displacement measuring component and the actual rotation angle of the connecting gear 23 from the angle measuring component 30.

[0102] Next, the calculation module 4 determines the theoretical rotation angle of the connecting gear 23 based on the actual displacement of the rack 101. The theoretical rotation angle of the connecting gear 23 can be calculated according to the following formula (1):

[0103]

[0104] Wherein, θ is the theoretical rotation angle of the connecting gear 23, L is the actual displacement of the rack 101, r is the pitch circle radius of the first gear 20 (the pitch circle is a size reference chosen for the convenience of gear design and manufacturing; the specific calculation formula for the pitch circle radius is number of teeth × module / 2; the number of teeth and module of the first gear 20 can be obtained in advance and stored in the calculation module 4, or the value of the pitch circle radius of the first gear 20 can be directly stored in the calculation module 4), and i is the transmission ratio between the second gear 22 and the connecting gear 23, which can be understood as the ratio of the number of teeth of the connecting gear 23 to the number of teeth of the second gear 22, i.e., i is the number of teeth of the connecting gear 23 / the number of teeth of the second gear 22. It should be noted that the number of teeth of the connecting gear 23 and the number of teeth of the second gear 22 are values ​​that can be obtained in advance and stored in the calculation module 4 based on the structural parameters of the gears, and the ratio between the two can also be pre-stored in the calculation module 4.

[0105] The current displacement of the floating component 10 is determined based on the absolute value of the difference between the actual rotation angle and the theoretical rotation angle.

[0106] Specifically, by comparing the absolute value of the difference between the actual rotation angle and the theoretical rotation angle of the connecting gear 23 with the rotation angle threshold according to the following formula (2), it can be determined whether wear has occurred between the meshing surfaces of the rack 101 and the first gear 20, and between the meshing surfaces of the second gear 22 and the connecting gear 23. Thus, different methods can be used to determine the current displacement of the rack 101 under different wear conditions:

[0107] |θ-θ0|≥a (2)

[0108] Where θ is the theoretical rotation angle of the connecting gear 23, θ0 is the actual rotation angle of the connecting gear 23, and a is a preset rotation angle threshold, which can be 0.1°.

[0109] The specific method for determining wear and tear is as follows:

[0110] If the absolute value of the difference between the actual rotation angle and the theoretical rotation angle is less than the rotation angle threshold, then the current displacement of the floating component 10 is the actual displacement of the floating component 10.

[0111] When the absolute value of the difference between the theoretical angle and the actual angle is less than the preset angle threshold a, it indicates that the error between the two is small, no wear has occurred or the wear is not serious, and it does not affect the final oil level calculation. The actual displacement of the floating component 10 can be directly used as the current displacement. Since the mathematical model for calculating the current oil level stored in the calculation module 4 is the correspondence between the current angle of the driven part and the current oil level, it is necessary to convert the current displacement into the current angle before calculating the current oil level. That is, step S2: determine the current angle of the driven part based on the current displacement of the floating component 10; the current displacement is converted into the current angle by the following formula (3):

[0112]

[0113] Where θ' is the current rotation angle of the connecting gear 23, r is the pitch circle radius of the first gear 20 (the specific calculation formula for the pitch circle radius is the number of teeth × module / 2), i can be understood as the ratio of the number of teeth of the connecting gear 23 to the number of teeth of the second gear 22, that is, i is the number of teeth of the connecting gear 23 / the number of teeth of the second gear 22, and l is the current displacement.

[0114] S3. Determine the current oil level of the transformer based on the current rotation angle of the driven part, specifically according to the following formula (4):

[0115] H=θ'r+h (4)

[0116] Where H is the current oil level, h is the initial oil level, θ' is the current rotation angle of the connecting gear 23, and r is the pitch circle radius of the first gear 20 (the specific calculation formula for the pitch circle radius is number of teeth × module / 2).

[0117] If the absolute value of the difference between the actual rotation angle and the theoretical rotation angle is greater than or equal to the rotation angle threshold, the displacement compensation amount of the floating component 10 is determined based on the difference between the actual rotation angle and the theoretical rotation angle and the usage time of the oil level gauge. The current displacement of the floating component 10 is the sum of the actual displacement of the floating component 10 and the displacement compensation amount.

[0118] Specifically, when the absolute value of the difference between the actual rotation angle and the theoretical rotation angle is greater than or equal to the preset rotation angle threshold a, it indicates that the error between the two is large and severe wear has occurred between the meshing teeth. In this case, the calculation result of the oil level value will be inaccurate. Therefore, compensation calculation is required to make up for the error caused by the wear of the meshing surface. The compensation is performed by the following formula (5):

[0119] ΔL=k(θ-θ0)+bT (5)

[0120] Wherein, ΔL is the displacement compensation amount of rack 101, k is the conversion coefficient between the rotation angle difference and the displacement obtained based on actual experience, b is the dynamic compensation coefficient (which is related to factors such as materials, site environment, and temperature, and is obtained through experience accumulation), and T is the usage time of the oil level gauge (the usage time can be collected by a timer, and the unit of time is years).

[0121] The current displacement of rack 101 after correction and compensation is determined according to the following formula (6):

[0122] l=ΔL+L (6)

[0123] Where l is the current displacement, ΔL is the displacement compensation amount of rack 101, and L is the actual displacement of rack 101.

[0124] Since the mathematical model for calculating the current oil level stored in the calculation module 4 is the correspondence between the current rotation angle of the driven part (connecting gear 23) and the current oil level, it is necessary to convert the current displacement into the current rotation angle of the driven part (connecting gear 23) before calculating the current oil level. The conversion process of the current displacement into the current rotation angle is described in the above formulas (3) and (4), thereby determining the current oil level.

[0125] It should be noted that, in addition to the specific embodiments described above, those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Although the description of the present invention will be presented in conjunction with preferred embodiments, this does not mean that the features of the invention are limited to those embodiments. On the contrary, the purpose of describing the invention in conjunction with embodiments is to cover other options or modifications that may be derived based on the claims of the present invention. To provide a thorough understanding of the invention, many specific details will be included in the following description. The invention may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of the invention, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0126] It should be noted that in this specification, similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0127] In the description of this embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship that the product of the invention is usually placed in during use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the present invention.

[0128] The terms “first”, “second”, etc., are used only to distinguish descriptions and should not be interpreted as indicating or implying relative importance.

[0129] In the description of this embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set up," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0130] While the present invention has been illustrated and described with reference to certain preferred embodiments, those skilled in the art should understand that the above description is a further detailed explanation of the invention in conjunction with specific embodiments, and should not be construed as limiting the specific implementation of the invention to these descriptions. Various changes in form and detail can be made by those skilled in the art, including several simple deductions or substitutions, without departing from the spirit and scope of the invention.

Claims

1. An oil level gauge, characterized in that, It includes a housing and a float assembly, a transmission assembly, a measurement module, and a computing module mounted on the housing; wherein The float assembly includes a floating component that can move vertically in response to changes in the oil surface, and the floating component includes an engaging portion; The transmission assembly includes a driven part that is drivenly connected to the engaging part. In response to the movement of the floating component along the vertical direction, the engaging part can drive the driven part to rotate. The measurement module includes a displacement measuring component and an angle measuring component. The displacement measuring component is used to detect the actual displacement of the floating component in the vertical direction. The angle measuring component is installed in the housing and connected to the driven part. The angle measuring component is used to detect the actual rotation angle of the driven part. The calculation module is communicatively connected to the displacement measuring component and the angle measuring component, respectively, and is used to receive the actual displacement of the floating component sent by the displacement measuring component and the actual rotation angle of the driven part sent by the angle measuring component. Based on the actual displacement of the floating component, the module determines the theoretical rotation angle of the driven part, and based on the absolute value of the difference between the actual rotation angle and the theoretical rotation angle, the module determines the current displacement of the floating component, the module determines the current rotation angle of the driven part, and the module determines the current oil level value of the transformer based on the current rotation angle of the driven part. Wherein, if the absolute value of the difference between the actual rotation angle and the theoretical rotation angle is less than the rotation angle threshold, then the current displacement of the floating component is the actual displacement of the floating component; if the absolute value of the difference between the actual rotation angle and the theoretical rotation angle is greater than or equal to the rotation angle threshold, then the displacement compensation amount of the floating component is determined according to the difference between the actual rotation angle and the theoretical rotation angle and the usage time of the oil level gauge, and the current displacement of the floating component is the sum of the actual displacement of the floating component and the displacement compensation amount; The formula for calculating the displacement compensation amount is: in, The displacement compensation amount is given by k, where k is the conversion coefficient between the difference between the actual rotation angle and the theoretical rotation angle and the displacement. For the theoretical turning angle, Let be the actual turning angle, b be the dynamic compensation coefficient, and T be the usage time.

2. The oil level gauge as described in claim 1, characterized in that, The meshing part is a rack extending along the vertical direction, and the driven part is a connecting gear. The connecting gear is rotatably supported on the housing by the angle measuring component. When the rack moves along the vertical direction, the connecting gear rotates under the drive of the rack. The displacement measuring component is used to collect the actual displacement of the rack and send it to the calculation module.

3. The oil level gauge as described in claim 2, characterized in that, The transmission assembly further includes a first gear rotatably supported on the housing via a connecting shaft. The rack meshes with the first gear, and the first gear is connected to the connecting gear in a transmission manner. The first gear can rotate relative to the housing about a first axis under the drive of the rack, and in conjunction with the rotation of the connecting shaft about the first axis, and the rotation of the connecting gear relative to the housing about a second axis. The first axis is the axis of the connecting shaft, and the second axis is parallel to the first axis.

4. The oil level gauge as described in claim 3, characterized in that, The transmission assembly further includes a second gear rotatably supported on the housing via the connecting shaft. The first gear and the second gear are respectively fixedly connected to both ends of the connecting shaft. The second gear meshes with the connecting gear, and the second gear can rotate around the first axis under the drive of the first gear, thereby causing the connecting gear to rotate relative to the housing around the second axis. When the transmission assembly includes the connecting gear, the first gear, and the second gear, the theoretical rotation angle of the driven part is determined based on the actual displacement of the floating component, the pitch circle radius of the first gear, and the transmission ratio between the second gear and the connecting gear.

5. The oil level gauge as described in claim 4, characterized in that, The float assembly further includes a rod-shaped guide member adapted to and connected to the floating component. The rod-shaped guide member is fixed to the housing and extends along the vertical direction. The floating component is slidably connected to the rod-shaped guide member along the vertical direction.

6. The oil level gauge as described in claim 5, characterized in that, The rod-shaped guiding component is a guide rod, and the floating component also includes a sleeve and a float. The sleeve is formed on the side of the rack away from the first gear and slides with the guide rod. The float is fixedly connected to the side of the rack away from the first gear by a connecting rod and is spaced apart from the sleeve in the vertical direction. The float is used to float on the surface of the oil.

7. The oil level gauge as described in claim 4, characterized in that, The meshing teeth of the rack, the first gear, the second gear, and the connecting gear are all coated with a diamond-like coating.

8. The oil level gauge according to any one of claims 1 to 7, characterized in that, The computing module includes a processing unit, a memory, and a communication unit, wherein... The communication unit is used to receive the actual displacement of the floating component sent by the displacement measuring component and the actual rotation angle of the driven part sent by the angle measuring component, and send them to the processing unit. The processing unit is used to determine the theoretical rotation angle of the driven part based on the actual displacement of the floating component, and to determine the current oil level value of the transformer based on the actual rotation angle and the theoretical rotation angle. The memory is used to store the actual rotation angle and the theoretical rotation angle of the driven part, the displacement compensation amount of the floating part, and the date on which the displacement compensation amount is recorded.

9. A transformer, comprising an oil tank, characterized in that, It also includes the oil level gauge according to any one of claims 1 to 8; wherein, The oil tank is filled with transformer oil, and the oil level gauge is used to be immersed inside the oil tank.

10. A method for calculating transformer oil level, characterized in that, The calculation is performed using the oil level gauge as described in any one of claims 1 to 8, the calculation method comprising: S1. Obtain the actual displacement of the floating component in the vertical direction and the actual rotation angle of the driven part. Determine the theoretical rotation angle of the driven part based on the actual displacement of the floating component in the vertical direction, and determine the current displacement of the floating component based on the absolute value of the difference between the actual rotation angle and the theoretical rotation angle. Wherein, if the absolute value of the difference between the actual rotation angle and the theoretical rotation angle is less than the rotation angle threshold, then the current displacement of the floating component is the actual displacement of the floating component; if the absolute value of the difference between the actual rotation angle and the theoretical rotation angle is greater than or equal to the rotation angle threshold, then the displacement compensation amount of the floating component is determined according to the difference between the actual rotation angle and the theoretical rotation angle and the usage time of the oil level gauge, and the current displacement of the floating component is the sum of the actual displacement of the floating component and the displacement compensation amount; S2. Determine the current rotation angle of the driven part based on the current displacement of the floating component; S3. Determine the current oil level of the transformer based on the current rotation angle of the driven part.

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