Oil level gauge, transformer and calculation method of oil level value of transformer

Abstract

The invention provides an oil level gauge, a transformer and a transformer oil level value calculation method.The oil level gauge comprises a shell, a floater assembly, a transmission assembly, a measuring module and a calculation module, a floating part of the floater assembly can move along with changes of the oil surface, and the floating part comprises a meshing part; the transmission assembly comprises a driven part meshed with the meshing part, and the meshing part can drive the driven part of the transmission assembly to rotate in response to movement of the floating part in the vertical direction; a displacement measuring part of the measuring module is used for detecting the actual displacement of the floating part moving in the vertical direction, and an angle measuring part is used for detecting the actual rotation angle of the driven part. When large abrasion exists between the meshing part and the driven part, the calculation module can solve the problem that the oil level value is not accurately calculated due to transmission ratio drifting caused by abrasion through compensation calculation, and according to the scheme, the current oil level value is determined by calculating parameters such as the meshed theoretical rotation angle and the current rotation angle of the driven part after displacement compensation.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of oil level detection, and particularly relates to an oil level meter, a transformer and a method for calculating a transformer oil level value. BACKGROUND

[0002] A transformer is a core device for changing voltage levels in a power system, and is widely used in power transmission, industrial production, daily life and other fields. Its core function is to raise or lower voltage to meet the needs of different scenarios.

[0003] According to the cooling method, the transformer can be divided into many types, among which the oil-immersed transformer is a relatively common type. In the oil-immersed transformer, the insulating oil is used as the cooling medium, and the heat is transferred to the heat sink through the natural convection or forced circulation of the oil. The oil level meter in the oil-immersed transformer is a key monitoring device of the oil-immersed transformer, which is used to detect the insulating oil level in real time and prevent equipment failure caused by abnormal oil level.

[0004] The conventional mechanical oil level meter used in the prior art converts the linear motion of the float into the rotation of the pointer through the gear and rack mechanism. For example, the patent with the publication number CN221725332U discloses a new transformer oil level meter, which converts the linear motion of the float into the rotational motion of the gear through the meshing of the rack and the gear, and then obtains the height of the insulating oil by reading the reading of the scale disc. However, the meshing surface of the gear and the rack will be worn after long-term operation of the oil level meter (especially the hardening of the oil at low temperature aggravates the wear), which leads to inaccurate measurement of the actual oil level value. SUMMARY

[0005] The purpose of the present application is to solve the problem of inaccurate measurement of the actual oil level value caused by the wear of the meshing surface of the gear and the rack after long-term operation of the oil level meter in the prior art.

[0006] To solve the above technical problems, the embodiment of the present application discloses an oil level gauge, comprising a shell and a float assembly, a transmission assembly, a measurement module and a calculation module installed on the shell. The float assembly comprises a floating component that can move along the vertical direction with the change of the oil surface, and the floating component comprises an engaging part. The transmission assembly comprises a driven part in transmission connection with the engaging part, and the engaging part can drive the driven part to rotate in response to the movement of the floating component along the vertical direction. The measurement module comprises a displacement measurement component and an angle measurement component, the displacement measurement component is used to detect the actual displacement of the floating component moving along the vertical direction, and the angle measurement component is installed on the shell and connected with the driven part, and the angle measurement component is used to detect the actual rotation angle of the driven part. The calculation module is in communication connection with the displacement measurement component and the angle measurement component, respectively, and is used to receive the actual displacement of the floating component moving sent by the displacement measurement component and the actual rotation angle of the driven part rotating sent by the angle measurement component, determine the theoretical rotation angle of the driven part rotating according to the actual displacement of the floating component moving, determine the current displacement of the floating component according to the absolute value of the difference between the actual rotation angle and the theoretical rotation angle, determine the current rotation angle of the driven part according to the current displacement of the floating component, and determine the current oil level value of the transformer according to the current rotation angle of the driven part. If the absolute value of the difference between the actual rotation angle and the theoretical rotation angle is less than the rotation angle threshold value, 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 value, 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 use 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.

[0007] By adopting the above technical scheme, the oil level gauge is used for oil-immersed transformers, and the float assembly, the transmission assembly, the measurement module and the calculation module of the oil level gauge are all installed on or in the shell, so that the oil level gauge is entirely immersed in the oil, and the shell is in communication with the outside of the shell, and the oil position in the shell is always the same as the oil position outside the shell. The floating component of the float assembly changes synchronously along the vertical direction with the position of the oil surface, so that the displacement change of the floating component can directly reflect the height change of the oil surface. The linear motion of the floating component along the vertical direction is converted into the rotary motion of the driven part through the mutual engagement of the driven part of the transmission assembly and the engaging part of the floating component. Through the mathematical model between the rotation angle of the driven part and the current oil level value stored in advance in the calculation module, the current oil level value can be obtained after the current rotation angle of the driven part (the current rotation angle of the driven part is determined according to the current displacement of the floating component) is substituted.

[0008] However, due to the increase of the running time of the oil level gauge and the influence of the hardening of the oil at low temperature, wear occurs between the meshing surfaces, and therefore it is necessary to determine whether there is large wear between the meshing part and the driven part by the calculation module, and to perform wear compensation calculation when large wear occurs, so as to calculate the accurate current oil level value. Therefore, the actual displacement change of the floating part with the oil surface is measured by the displacement measuring component of the measurement module, the actual rotation angle of the driven part rotating under the driving of the meshing part is measured by the angle measuring component of the measurement module, and in the calculation module, the theoretical rotation angle of the driven part can be determined according to the actual displacement of the floating part, and further, whether there is wear error of the oil level gauge can be determined according to the actual rotation angle and the theoretical rotation angle. When there is large wear between the meshing part and the driven part, the displacement compensation amount of the floating part can be determined according to the difference between the actual rotation angle and the theoretical rotation angle and the use time of the oil level gauge, and the current displacement of the floating part is the sum of the actual displacement of the floating part and the displacement compensation amount, that is, the current displacement of the floating part is obtained after compensation calculation, and the current rotation angle of the driven part can be determined according to the current displacement and the transmission ratio between the meshing part and the driven part, and then the current rotation angle of the driven part is substituted into the mathematical model between the rotation angle of the driven part and the current oil level value stored in the calculation module in advance, so as to determine the current oil level value of the transformer. In addition, the calculation module also has the functions of data storage and remote signal transmission, and can store the measured and calculated data for the operation and maintenance personnel to obtain; and can also remotely transmit the calculated current oil level value, so as to realize remote monitoring of the oil level value and related equipment maintenance.

[0009] According to another specific embodiment of the present application, the embodiment of the present application discloses an oil level gauge, the meshing part is a rack extending in the vertical direction, the driven part is a connecting gear, the connecting gear is rotatably supported on the housing through the angle measuring component, when the rack moves in the vertical direction, the connecting gear rotates under the driving 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] By adopting the above technical scheme, the rack can move vertically with the oil surface when the rack is arranged to extend in the vertical direction, and the rack and the connecting gear are kept in transmission during the movement, so as to convert the linear movement of the rack into the rotary movement of the connecting gear. The corresponding relationship between the rotation angle of the connecting gear and the oil level value is pre-stored in the calculation module, and the current rotation angle of the connecting gear can be determined according to the actual displacement of the rack, the actual rotation angle of the connecting gear and the theoretical rotation angle of the connecting gear, and then the current oil level value of the transformer can be determined.

[0011] According to another specific embodiment of the present application, the embodiment of the present application discloses a transformer, which comprises an oil tank and the 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 soak in the inside of the oil tank.

[0012] By using the technical scheme, the transformer can compensate the oil level under the wearing condition, so that the accurate oil level value is obtained, and remote communication can be realized, when the transformer is arranged at a place, such as an unattended substation, sea, desert or the like, which is inconvenient for the operation and maintenance personnel to directly view, the measurement data can be remotely transmitted, and remote monitoring and maintenance are supported.

[0013] According to another specific embodiment of the present application, the embodiment of the present application discloses a calculation method of a transformer oil level value, which is calculated by using an oil level gauge, and the calculation method comprises:

[0014] S1, an actual displacement of the floating component moving in the vertical direction and an actual rotation angle of the driven part are obtained, a theoretical rotation angle of the driven part is determined according to the actual displacement of the floating component moving in the vertical direction, and a current displacement of the floating component is determined according to an absolute value of a 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 a rotation angle threshold value, 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 value, a displacement compensation amount of the floating component is determined according to the difference between the actual rotation angle and the theoretical rotation angle and a use time of the oil level gauge, and the current displacement of the floating component is a sum of the actual displacement of the floating component and the displacement compensation amount; S2, a current rotation angle of the driven part is determined according to the current displacement of the floating component; S3, a current oil level value of the transformer is determined according to the current rotation angle of the driven part.

[0015] In summary, the oil level gauge, transformer and transformer oil level value calculation method provided by the application, the oil level gauge comprises a shell, a float assembly, a transmission assembly, a measurement module and a calculation module installed on the shell. The displacement change of the floating part of the float assembly 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 rotary motion of the driven part through the meshing of the driven part and the meshing part of the floating part, and the current oil level value can be obtained by substituting the current rotation angle of the driven part (the current rotation angle of the driven part is determined according to the current displacement of the floating part) into the mathematical model between the rotation angle of the driven part and the current oil level value stored in the calculation module. When there is a large wear between the meshing part and the driven part, the calculation module can compensate the current displacement of the floating part, and then the current rotation angle of the driven part can be determined according to the current displacement and the transmission ratio between the meshing part and the driven part, and then the current rotation angle of the driven part is substituted into the mathematical model between the rotation angle of the driven part and the current oil level value stored in the calculation module, so that the current oil level value of the transformer can be determined, so that the mechanical wear error of 0.01mm can be corrected. In addition, the calculation module also has the functions of data storage and remote signal transmission, and can store the measured and calculated data, so that the operation and maintenance personnel can obtain the data to trace the fault; the current oil level value calculated can also be transmitted remotely, realizing remote monitoring of the oil level value and related equipment maintenance. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1a One of the overall structure schematic diagrams of the oil level gauge provided for the embodiment 1 of the application;

[0017] Figure 1b Another overall structure schematic diagram of the oil level gauge provided for the embodiment 1 of the application;

[0018] Figure 1c Still another overall structure schematic diagram of the oil level gauge provided for the embodiment 1 of the application;

[0019] Figure 2 Flow chart of the oil level value calculation method of the oil level gauge provided for the embodiment 1 of the application;

[0020] Figure 3 Structure block diagram of the measurement module and the calculation module of the oil level gauge provided for the embodiment 1 of the application;

[0021] Figure 4 Top view of the oil level gauge provided for the embodiment 1 of the application;

[0022] Figure 5 For Figure 4 Sectional view along the direction of A-A.

[0023] BRIEF DESCRIPTION OF DRAWINGS:

[0024] 1. float assembly; 10. floating member; 101. rack; 102. sleeve; 103. float; 104. connecting rod; 11. rod-shaped guide member;

[0025] 2. transmission assembly; 20. first gear; 21. connecting shaft; 22. second gear; 23. connecting gear;

[0026] 3. measurement module; 30. angle measurement member;

[0027] 4. calculation module; 40. processing unit; 41. memory; 42. communication unit;

[0028] 5. housing. DETAILED DESCRIPTION

[0029] The transformer is a core device for changing voltage levels in the power system, and the transformer is widely used in power transmission, industrial production, daily life and other fields. Its core function is to raise or lower the voltage to meet the needs of different scenarios.

[0030] The transformer is divided into many types according to the cooling method, among which the oil-immersed transformer is a relatively common one. The internal insulation oil of the oil-immersed transformer is used as the cooling medium, and the heat is transferred to the heat sink through the natural convection or forced circulation of the oil.

[0031] However, the transformers such as unattended substations, offshore wind power transformers, and rail transit traction transformers are located in remote places, and it is not convenient to monitor and observe the oil level value in real time. The oil level value is a key factor for determining whether the equipment has failed, so real-time detection of the insulation oil level can prevent equipment failure caused by abnormal oil level. In the oil-immersed transformer, the oil level meter is a key monitoring device of the oil-immersed transformer, which is used to detect the insulation oil level in real time and prevent equipment failure caused by abnormal oil level.

[0032] The traditional mechanical oil level meter converts the linear motion of the float into the rotation of the pointer through the gear-rack mechanism, but such oil level meter will have meshing surface wear of the gear and rack after long-term operation (especially the hardening of the oil at low temperature aggravates the wear), transmission ratio drift occurs, resulting in inaccurate measurement of the actual oil level value. The error can reach ±0.1mm / year, which needs frequent manual calibration. And under the extreme temperature difference of-40℃~120℃, the difference of thermal expansion coefficient between metal gear and shell (such as steel and aluminum alloy Δα≈11×10 -6 / ℃) is easy to cause the change of meshing gap, and the conventional lubricating grease will solidify at low temperature (pour point >-20℃), and the viscosity will decrease at high temperature (evaporation rate >5% at 120℃).

[0033] Therefore, the mechanical structure of the existing oil level meter core is covered by the shell and cannot be observed, and most transformers are arranged in remote outdoor areas, which is inconvenient for manual operation and calibration, and the mechanical wear caused by long-term operation or low-temperature operation is serious, which can cause inaccurate measurement of the actual oil level value.

[0034] To solve the above problems, the oil level meter can determine whether the meshing tooth mechanical wear occurs in the oil level meter, and compensate the transmission ratio when the meshing tooth mechanical wear is serious to correct the transmission ratio drift caused by the wear, so that the current oil level value can be accurately calculated, even if the internal structure of the oil level meter cannot be observed or the transformer is arranged in a remote area and cannot be monitored in real time.

[0035] To make the purpose, technical solutions and advantages of the present application clearer, the embodiments of the present application are further described in detail below with reference to the drawings.

[0036] Example 1

[0037] The oil level meter provided by the present application is used in an oil-immersed transformer, the oil level meter is entirely immersed in oil, as shown in Figures 1a-1c , the oil level meter comprises a shell 5 (in order to show the structure in the shell 5, Figure 1c only the side wall and the bottom of the shell 5 are shown), the shell 5 is in communication with the outside of the shell 5, the oil level position in the shell 5 is always the same as the oil level position outside the shell 5, the float assembly 1, the transmission assembly 2, the measurement module 3 and the calculation module 4 of the oil level meter are all installed on or in the shell 5, and the floating part 10 of the float assembly 1 in the shell 5 changes synchronously with the position of the oil surface in the vertical direction, so the displacement change of the floating part 10 can directly reflect the height change of the oil surface.

[0038] The floating part 10 comprises an engaging part, and the transmission assembly 2 comprises a driven part in transmission connection with the engaging part, the driven part is the output end of the transmission assembly 2, that is, the actual measurement object when the angle measurement part 30 described below measures the rotation angle. When the floating part 10 moves in the vertical direction with the oil surface, the engaging part can drive the driven part to rotate, converting the linear movement of the floating part 10 in the vertical direction into the rotary motion of the driven part, and by converting the slight linear displacement change of the floating part 10 into the rotation angle change of the driven part, the transmission ratio between the engaging part and the driven part can be reasonably set to convert the smaller linear displacement change into a larger rotation angle value change, so that the oil level meter can more sensitively and accurately reflect the oil level change through the rotation angle value.

[0039] The actual parameters measured by the measuring module 3 are used to determine whether wear occurs and to perform transmission ratio compensation calculation, wherein the displacement measuring component is used to detect the actual displacement of the floating component 10 moving in the vertical direction, the angle measuring component 30 is installed on the housing 5 and connected with the driven part, and 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 obtain 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 amount of the floating component 10, determine the current displacement of the floating component 10, determine the current rotation angle of the driven part according to the current displacement, and determine the current oil level value of the transformer according to the current rotation angle of the driven part.

[0041] In order to facilitate understanding of the specific structure and working principle of the oil level meter, the oil level meter is described in detail as follows:

[0042] As shown in Figures 1a-1c The housing 5 is used to provide rigid support for the float assembly 1, the transmission assembly 2, the measuring module 3 and the calculation module 4, and the housing 5 is the basic component of the oil level meter, which can be a cube with a cavity or other irregular solid structure, and the specific limitation is not made here, and the person skilled in the art can set it according to the needs.

[0043] The float assembly 1 is the core component of the oil level meter for reflecting the change of the oil level position, and the floating component 10 is arranged to move with the oil liquid under the action of buoyancy when the oil liquid height changes. The volume and density of the floating component 10 can be reasonably set by the person skilled in the art according to the density of the oil liquid. The floating component 10 can float on the oil liquid surface as a whole, or part of it can float on the oil liquid surface and the other part can be immersed in the oil liquid. For example, a float ball can be arranged at one end of the floating component 10, the float ball floats on the oil liquid surface, and the other part of the floating component 10 is dragged to move with the float ball. In order to ensure that the actual displacement of the floating component 10 in the vertical direction is the change in height of the oil liquid surface, a guide member such as a guide rod can be connected to the floating component 10 to guide the floating component 10 to move linearly in the vertical direction.

[0044] The meshing part (for example, the rack 101) and the driven part (for example, the connecting gear 23) can be connected in transmission through mutual meshing. For example, the meshing part of the floating component 10 can be a rack 101 or a gear. When the meshing part is a rack 101, the meshing teeth on the rack 101 are arranged in a vertical direction. The driven part can be a gear with an axis parallel to the vertical direction or a gear with an axis perpendicular to the vertical direction. When the gear axis of the driven part is parallel to the vertical direction, the rack 101 and the gear are meshed through helical teeth. When the meshing part is a gear, the axis of the gear can be parallel to the vertical direction or perpendicular to the vertical direction. The driven part can be a gear with an axis parallel to the vertical direction or a gear with an axis perpendicular to the vertical direction. The meshing teeth at the meshing part of the two gears are helical or straight, which is a conventional means in the art.

[0045] The meshing part (for example, the rack 101) and the driven part (for example, the connecting gear 23) can also be connected in transmission through an intermediate gear transmission structure. For example, an intermediate gear can be arranged between the meshing part and the driven part. The intermediate gear is meshed with the meshing part and the driven part, so that the meshing part and the driven part are connected in transmission. Alternatively, two coaxially connected intermediate gears can be arranged between the meshing part and the driven part. One intermediate gear is meshed with the meshing part, and the other intermediate gear is meshed with the driven part, so that the meshing part and the driven part are connected in transmission. Of course, more intermediate gears can also be arranged between the meshing part and the driven part.

[0046] It should be noted that the meshing teeth in the transmission assembly 2 are coated with a diamond-like carbon coating. For example, the meshing teeth of the meshing part, the driven part, and the intermediate gear (if arranged) are coated with a diamond-like carbon coating. Diamond-like carbon (DLC) is an amorphous carbon-based thin film with excellent comprehensive performance, high hardness, low friction, and wear resistance. The thickness of the diamond-like carbon coating can be between 1 μm and 3 μm, and the preferred thickness is 2 μm. The diamond-like carbon coating can effectively improve the wear resistance of the meshing part and the driven part. The wear life of the oil level meter meshing surface provided by the present embodiment is improved by 3 times.

[0047] In one specific embodiment of the present application, as shown in Figure 1aAs shown, the engaging part is a rack 101 extending in the vertical direction, the driving part is a connecting gear 23, and the two are in meshing engagement, the angle measuring component 30 is arranged on one side of the disc surface of the connecting gear 23, the connecting gear 23 is rotatably supported on the housing 5 through the angle measuring component 30, when the axis of the connecting gear 23 is perpendicular to the extension direction of the rack 101, the angle measuring component 30 is connected with the side wall of the housing 5, the rack 101 and the connecting gear 23 are in meshing engagement through straight teeth; when the axis of the connecting gear 23 is parallel to the extension direction of the rack 101 (i.e. Figure 1a the state shown), the angle measuring component 30 is fixedly connected with the upper side or the lower side of the housing 5, the rack 101 and the connecting gear 23 are in meshing engagement through helical teeth.

[0048] For the convenience of understanding, the axis of the connecting gear 23 is parallel to the vertical direction in the following description.

[0049] Specifically, when the rack 101 moves in the vertical direction, the connecting gear 23 rotates relative to the housing 5 under the driving of the rack 101, after the actual displacement of the rack 101 in the vertical direction and the actual rotation angle of the connecting gear 23 are measured, the theoretical rotation angle of the connecting gear 23 can be calculated according to the actual displacement of the rack 101 and the pitch circle radius of the connecting gear 23, and the wear between the meshing teeth of the connecting gear 23 and the rack 101 (driving ratio drift judgment) can be judged by comparing the theoretical rotation angle and the actual rotation angle of the connecting gear 23, the displacement compensation of the rack 101 (driving ratio compensation) is performed in the case of large wear, and 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 according to the current displacement of the rack 101 and the pitch circle radius of the connecting gear 23, so that the accurate oil level value can be finally calculated.

[0050] In another specific embodiment of the present application, as shown, Figure 1b when the rack 101 and the connecting gear 23 are indirectly connected in transmission through an intermediate gear, the transmission assembly 2 further comprises a first gear 20 rotatably supported on the housing 5 through a connecting shaft 21, the rack 101 can be in meshing engagement with the first gear 20, so that the first gear 20 can rotate relative to the housing 5 about a first axis (the first axis is the axis of the connecting shaft 21) under the driving of the rack 101, the first gear 20 is further in transmission connection with the connecting gear 23, when the first gear 20 and the connecting gear 23 are directly in meshing transmission, the rack 101 can rotate about the first axis through the first gear 20, and then the connecting gear 23 rotates relative to the housing 5 about a second axis, wherein the second axis is parallel to the first axis.

[0051] Specifically, when the rack 101 moves along the vertical direction, the connecting gear 23 rotates relative to the housing 5 under the drive of the first gear 20, and after the actual displacement of the rack 101 along the vertical direction and the actual rotation angle of the connecting gear 23 are measured, the theoretical rotation angle of the connecting gear 23 can be calculated according to the actual displacement of the rack 101, the pitch circle radius of the first gear 20, and the transmission ratio (a fixed value stored in the calculation module 4 in advance) between the first gear 20 and the connecting gear 23, and the wear between the meshing teeth in the transmission assembly 2 (including the meshing teeth between the first gear 20 and the rack 101 and the meshing teeth between the first gear 20 and the connecting gear 23) can be judged by comparing the theoretical rotation angle of the connecting gear 23 and the actual rotation angle, the displacement of the rack 101 is compensated (the transmission ratio is compensated) in the case of greater wear, and 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 according to the current 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, so that the accurate oil level value can be calculated.

[0052] In another specific embodiment of the present application, as shown in Figure 1c When the rack 101 and the connecting gear 23 are indirectly connected through an intermediate gear, the transmission assembly 2 can further include a second gear 22 in addition to the first gear 20, the second gear 22 is also rotatably supported on the housing 5 through 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 and the connecting gear 23 are in meshing relationship. When the rack 101 moves along the vertical direction, the first gear 20 can rotate relative to the housing 5 about the first axis (the first axis is the axis of the connecting shaft 21) under the drive of the rack 101, and since the second gear 22 and the first gear 20 are coaxially connected through the connecting shaft 21, the second gear 22 can rotate about the first axis under the drive of the first gear 20, and drive the connecting gear 23 to rotate relative to the housing 5 about the second axis.

[0053] Specifically, when the rack 101 moves in the vertical direction, the connecting gear 23 rotates relative to the housing 5 under the drive of the second gear 22. After the actual displacement of the rack 101 in the vertical direction and the actual rotation angle of the connecting gear 23 are measured, the theoretical rotation angle of the connecting gear 23 can be calculated according to the actual displacement of the rack 101, the radius of the indexing circle of the first gear 20, and the transmission ratio between the second gear 22 and the connecting gear 23 (a fixed value stored in the computing module 4). By comparing the theoretical rotation angle and the actual rotation angle of the connecting gear 23, the wear between the meshing teeth in the transmission assembly 2 (including the meshing teeth of the first gear 20 and the rack 101 and the meshing teeth of the second gear 22 and the connecting gear 23) can be determined (transmission ratio drift determination), and displacement compensation of the rack 101 can be performed in the case of heavy wear (transmission ratio compensation). Then, according to the wear condition, the current displacement of the rack 101 is determined, and the current rotation angle of the connecting gear 23 is calculated according to the current displacement of the rack 101, the radius of the indexing circle of the first gear 20, and the transmission ratio between the second gear 22 and the connecting gear 23. Finally, the accurate oil level value can be calculated, and the specific calculation method will be described in detail below.

[0054] It can be understood that by the above method, mechanical wear compensation between the meshing tooth surfaces of each oil level gauge can be achieved, and the measured oil level gauge is more accurate.

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

[0056] It should be further noted that the angle measuring component 30 can be an angle encoder. The working principle of the angle encoder is mainly to convert the rotation angle into an electrical signal. Commonly used are photoelectric and magneto-electric types:

[0057] The photoelectric angle encoder mainly consists of a light source, a grating disc, a photoelectric detector, a signal processing circuit, etc. The grating disc has many concentric circular transparent and opaque lines, which divide the disc into several equal parts. When the grating disc rotates with the rotating shaft, the transparent and opaque parts alternately block the light, and the photoelectric detector converts the light intensity change into an electrical signal. After signal processing by the circuit, a pulse signal or code signal corresponding to the rotation angle is output.

[0058] For an incremental encoder, a pulse is generated every time a line interval is passed, and the rotation angle can be determined by counting the number of pulses. At the same time, two sets of photoelectric detectors are usually provided to generate A-phase and B-phase pulse signals with a phase difference of 90°, and the phase relationship between the two can be used to determine the rotation direction. For an absolute encoder, each position corresponds to a unique binary code, and the code signal directly indicates the angle position.

[0059] The magneto-electric angle encoder mainly consists of a magnetic ring, a Hall element or a magnetoresistance element, etc. The magnetic ring is provided with a plurality of magnetic poles, and the Hall element or the magnetoresistance element is installed near the magnetic ring. When the rotating shaft drives the magnetic ring to rotate, the Hall element or the magnetoresistance element detects the change of the magnetic field intensity, thereby generating a corresponding electric signal. According to the change of the electric signal, the information of the rotation angle is obtained after conversion and calculation by a signal processing circuit.

[0060] Since the floating component 10 changes with the liquid surface in the vertical direction, in order to ensure that the displacement of the floating component 10 is always linear displacement, a guide structure needs to be arranged to guide the floating component 10 to move linearly, as shown in the figure, the float assembly 1 further comprises a rod-shaped guide component 11 connected with the floating component 10, the rod-shaped guide component 11 is fixed to the shell 5 and extends in the vertical direction, and the floating component 10 is slidingly connected to the rod-shaped guide component 11 in the vertical direction. Figures 1a-1c

[0061] It should be noted that the floating component 10 and the rod-shaped guide component 11 can realize mutual sliding through a sliding groove sliding rail cooperation, or through a ball sliding groove cooperation, or through a sleeve joint structure. Specifically, the rod-shaped guide component 11 can be a guide rod, a sliding groove can be formed on the side of the guide rod facing the floating component 10, a strip-shaped protrusion adapted to the sliding groove can be arranged at the corresponding position of the floating component 10, or a strip-shaped protrusion can be arranged on the side of the guide rod facing the rack 101, and a sliding groove adapted to the strip-shaped protrusion can be formed at the corresponding position 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 slidably cooperates with the guide rod. In addition, the floating component 10 can further include a float 103, the float 103 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 through a connecting rod 104, and the float 103 can be arranged in the vertical direction and spaced apart from the sleeve 102. When the oil surface changes in displacement, the floating float 103 can drive the rack 101 to move in the vertical direction, and the actual displacement of the rack 101 is collected by a displacement measuring component (not shown in the figure) arranged on the rack 101 and sent to the calculation module 4. The displacement measuring component can be arranged at the bottom, middle, top or other positions of the rack 101, as long as the displacement measuring component can measure the actual displacement of the rack 101 when the rack 101 moves in the vertical direction. The displacement measuring component, for example, can be a potentiometer type displacement sensor, a magnetostrictive displacement sensor, a capacitive displacement sensor, a photoelectric displacement sensor or an ultrasonic displacement sensor. Figures 1a-1c

[0062] ​​The computing module 4 is communicatively connected with the displacement measuring component and the angle measuring component 30. The actual displacement of the floating component 10 moving in the vertical direction is measured by the displacement measuring component of the measuring module 3. After the actual rotation angle of the driven part (see the connecting gear 23 in Figures 1a-1c particular, the connecting gear 23) is detected by the angle measuring component 30, the computing module 4 receives the actual displacement and the actual rotation angle, and then determines whether mechanical wear occurs and calculates the current oil level value of the transformer by the computing module 4.

[0063] It should be noted that the computing module 4 provided in the embodiment has the functions of communication, data processing and data storage, so it can receive real-time parameters collected by the sensor, and the related mathematical model for calculating the oil level value is also stored in the computing module 4 in advance, so that data processing can be realized, and the related data collected and calculated can also be stored.

[0064] Next, the specific calculation process of the oil level value will be described below with reference to the oil level gauge structure shown in Figure 1c FIG. 1. The engaging part is the rack 101, the driven part is the connecting gear 23, and the transmission assembly 2 further includes a first gear 20, a connecting shaft 21 and a second gear 22. As shown in Figure 2 FIG. 1, the specific calculation process of the oil level value is as follows.

[0065] Firstly, the computing module 4 receives the actual displacement of the rack 101 moving and the actual rotation angle of the connecting gear 23 rotating sent by the displacement measuring component and the angle measuring component 30.

[0066] Next, the computing module 4 determines the theoretical rotation angle of the connecting gear 23 rotating according to the actual displacement of the rack 101 moving. 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 (unit: degree), L is the actual displacement of the rack 101 moving, r is the pitch circle radius of the first gear 20 (the pitch circle is a size reference selected for the design and manufacture of the gear, and the specific calculation formula of the pitch circle radius is the number of teeth x module number / 2, the number of teeth and the module number of the first gear 20 can be pre-obtained and stored in the computing module 4, or the value of the pitch circle radius of the first gear 20 can be directly stored in the computing module 4), and i is the transmission ratio between the second gear 22 and the connecting gear 23, which can be understood as the tooth number ratio of the connecting gear 23 to the second gear 22, i.e. i is the tooth number of the connecting gear 23 / the tooth number of the second gear 22. It should be noted that the tooth number of the connecting gear 23 and the tooth number of the second gear 22 are values that can be pre-obtained according to the structural parameters of the gear and stored in the computing module 4, and the ratio of the two can also be pre-stored in the computing module 4.

[0069] Further, 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) can determine whether wear occurs between the meshing surface of the rack 101 and the first gear 20, between the meshing surface of the second gear 22 and the connecting gear 23, and further determine the current displacement of the rack 101 by different methods under different wear conditions:

[0070] |θ-θ0|≥a (2)

[0071] Wherein, 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 the preset rotation angle threshold, which can be specifically set to 0.1°.

[0072] The specific method for determining the wear condition is:

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

[0074]

[0075] Wherein, 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 of the pitch circle radius is the number of teeth × module number / 2), and i can be understood as the gear ratio of the connecting gear 23 and 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 value is determined according to the following formula (4):

[0077] H=θ’r+h (4)

[0078] Wherein, H is the current oil level value, h is the initial oil level value, 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 of the pitch circle radius is the number of teeth × module number / 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 serious wear occurs between the meshing teeth. In this case, the calculation result of the oil level value is inaccurate, and therefore compensation calculation is required to compensate for the error caused by the wear of the meshing surface. The compensation is performed through the following formula (5):

[0080] ΔL=k(θ-θ0)+bT (5)

[0081] Wherein, ΔL is the displacement compensation amount of the rack 101, k is a conversion coefficient between the rotation angle difference and the displacement obtained according to actual experience, b is a dynamic compensation coefficient (specifically related to factors such as material, site environment, temperature, etc., and 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 year).

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

[0083] l=ΔL+L (6)

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

[0085] Since the mathematical model stored in the calculation module 4 for calculating the current oil level value is the corresponding relationship between the current rotation angle of the driven part (connecting gear 23) and the current oil level value, the current displacement needs to be converted into the current rotation angle of the driven part (connecting gear 23) before the current oil level value is calculated. The conversion of the current displacement into the current rotation angle is described in the above formula (3) and formula (4), so as to determine the current oil level value.

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

[0087] In one of the specific embodiments of the present application, as shown in Figure 3 and Figure 5 The calculation module 4 includes a processing unit 40, a memory 41 and a communication unit 42.

[0088] Specifically, the communication unit 42 is configured to receive the actual displacement of the floating part 10 sent by the displacement measuring part and the actual rotation angle of the driven part sent by the angle measuring part 30, and send them to the processing unit 40; the communication unit 42 can be an RS485 interface, and communication is performed through a Modbus protocol, and remote calibration instruction receiving and data uploading are supported. The processing unit 40 is configured to determine the theoretical rotation angle of the driven part according to the actual displacement of the floating part 10, and determine the current oil level value of the transformer according to the actual rotation angle and the theoretical rotation angle. The memory 41 is configured to store the actual rotation angle and the theoretical rotation angle of the driven part, the displacement compensation amount of the floating part 10, and the date of recording the displacement compensation amount, and the memory 41 can be an electrically erasable programmable read-only memory (EEPROM), so that data is not lost after power failure, and calibration records for 10 years can be stored, which is convenient for later fault tracing.

[0089] Embodiment 2

[0090] The application also provides a transformer, which comprises an oil tank and the oil level meter provided in Embodiment 1, and the oil tank is filled with transformer oil, and the oil level meter is configured to be immersed in the oil tank. The transformer provided with the oil level meter can realize wear identification and self-calibration compensation, and can accurately calculate the current oil level value of the transformer.

[0091] The oil level meter is suitable for transformers of unattended substations, can support remote calibration, and reduce the risk of maintenance personnel climbing; is also suitable for offshore wind power transformers, can adapt to high-salt-mist and high-humidity environments, and has a corrosion-resistant coating with a service life of 15 years; and is also suitable for rail transit traction transformers, has an anti-vibration design (amplitude ≤ 5g), and ensures stable readings when a high-speed train is running.

[0092] Embodiment 3

[0093] The embodiment provides a calculation method of a transformer oil level value, which is used for calculating the oil level value of the oil level meter provided in Embodiment 1. The method can accurately identify the wear condition of the meshing tooth surface in the oil level meter, and perform self-calibration compensation when the wear is serious. By calculating the displacement compensation amount of the meshing part (which can be the rack 101 in FIG. 1) and the transmission ratio drift error between the meshing surfaces (for example, the meshing surfaces of the rack 101 and the first gear 20 in FIG. 1, and the meshing surfaces of the second gear 22 and the connecting gear 23) in the oil level meter, the current oil level value of the transformer can be accurately calculated.

[0094] The calculation method comprises: S1, acquiring actual displacement of the floating component 10 moving in the vertical direction and actual rotation angle of the driven part, determining theoretical rotation angle of the driven part according to the actual displacement of the floating component 10 moving in the vertical direction, and determining current displacement of the floating component according to absolute value of difference between the actual rotation angle and the theoretical rotation angle.

[0095] If the absolute value of the difference between the actual rotation angle and the theoretical rotation angle is less than the rotation angle threshold value, 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 value, 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 use 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, determining current rotation angle of the driven part according to the current displacement of the floating component 10.

[0097] S3, determining current oil level value of the transformer according to the current rotation angle of the driven part.

[0098] It should be noted that the calculation method can be automatically calculated by using a computer program, that is, the steps executed by the calculation module 4.

[0099] The calculation method is described below with the oil level gauge in Example 1 comprising the rack 101, the connecting gear 23, the first gear 20 and the second gear 22:

[0100] S1, acquiring actual displacement of the floating component 10 moving in the vertical direction and actual rotation angle of the driven part, determining theoretical rotation angle of the driven part according to the actual displacement of the floating component 10 moving in the vertical direction.

[0101] Specifically, first, the calculation module 4 acquires actual displacement of the rack 101 moving and actual rotation angle of the connecting gear 23 rotating sent from the displacement measuring component and the angle measuring component 30.

[0102] Next, the calculation module 4 determines theoretical rotation angle of the connecting gear 23 according to the actual displacement of the rack 101 moving, which 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 selected for the convenience of gear design and manufacture, and the specific calculation formula of the pitch circle radius is the number of teeth x module number / 2, the number of teeth and the module number 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), i is the transmission ratio between the second gear 22 and the connecting gear 23, which can be understood as the tooth number ratio of the connecting gear 23 and the second gear 22, that is, i is the tooth number of the connecting gear 23 / the tooth number of the second gear 22, it should be noted that the tooth number of the connecting gear 23 and the tooth number of the second gear 22 are both values that can be obtained in advance according to the structural parameters of the gear and stored in the calculation module 4, and the ratio of the two can also be pre-stored in the calculation module 4.

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

[0106] Specifically, 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) can determine whether wear occurs between the meshing surface of the rack 101 and the first gear 20, between the meshing surface of the second gear 22 and the connecting gear 23, and then different methods are used to determine the current displacement of the rack 101 under different wear conditions:

[0107] |θ-θ0|≥a (2)

[0108] Wherein, 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 specifically 0.1°.

[0109] The specific method for determining the wear condition is:

[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, the current displacement of the floating component 10 is the actual displacement of the floating component 10.

[0111] That is, when the absolute value of the difference between the theoretical rotation angle and the actual rotation angle is less than the preset rotation angle threshold a, it means that the error between the two is small, and there is no wear or the wear is not serious, which does not affect the final oil level value 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 value stored in the calculation module 4 is the corresponding relationship between the current rotation angle of the driven part and the current oil level value, it is necessary to convert the current displacement into the current rotation angle before calculating the current oil level value, that is, step S2, determining the current rotation angle of the driven part according to the current displacement of the floating component 10; the current displacement is converted into the current rotation angle by the following formula (3):

[0112]

[0113] wherein 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 of the pitch circle radius is the number of teeth x the module number / 2), i can be understood as the tooth ratio of the connecting gear 23 and 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 value of the transformer according to the current rotation angle of the transmission part, and specifically determine the current oil level value according to the following formula (4):

[0115] H = θ' r + h (4)

[0116] wherein H is the current oil level value, h is the initial oil level value, 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 of the pitch circle radius is the number of teeth x the module number / 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 value, then the displacement compensation amount of the floating part 10 is determined according to the difference between the actual rotation angle and the theoretical rotation angle and the use time of the oil level meter, and the current displacement of the floating part 10 is the sum of the actual displacement of the floating part 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 value a, it indicates that the error between the two is large, and serious wear occurs between the meshing teeth. In this case, the calculation result of the oil level value will be inaccurate, so compensation calculation is needed to compensate for the error caused by the wear of the meshing surface. The compensation is carried out through the following formula (5):

[0119] ΔL = k(θ-θ0) + bT (5)

[0120] wherein ΔL is the displacement compensation amount of the rack 101, k is a conversion coefficient between the rotation angle difference and the displacement obtained according to actual experience, b is a dynamic compensation coefficient (specifically related to factors such as material, site environment, temperature, etc., and obtained through experience accumulation), and T is the use time of the oil level meter (the use time can be collected by a timer, and the unit of time is year).

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

[0122] l = ΔL + L (6)

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

[0124] Since the mathematical model stored in the calculation module 4 for calculating the current oil level value is the correspondence between the current rotation angle of the driven part (connecting gear 23) and the current oil level value, the current displacement needs to be converted into the current rotation angle of the driven part (connecting gear 23) before the current oil level value is calculated. The conversion of the current displacement into the current rotation angle is described in the above formulas (3) and (4), so as to determine the current oil level value.

[0125] It should be noted that, in addition to the specific embodiments described above, other advantages and effects of the present application can be easily understood by those skilled in the art from the disclosure. Although the description of the present application will be introduced in combination with the preferred embodiments, it does not mean that the features of the present application are limited to the embodiments. On the contrary, the purpose of introducing the application in combination with the embodiments is to cover other options or modifications that can be extended based on the claims of the present application. In order to provide a deep understanding of the present application, many specific details will be included in the following description. The present application can also be implemented without using these details. In addition, in order to avoid confusion or obscure the focus of the present application, some specific details will be omitted in the description. It should be noted that, in the case of no conflict, the embodiments and features in the embodiments can be combined with each other.

[0126] It should be noted that, in this specification, similar reference numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0127] In the description of the present embodiment, it should be noted that the terms "upper", "lower", "inner", "bottom" and the like indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship commonly used when the product is used, and are only for the convenience of describing the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0128] The terms "first", "second", and the like are only used for differentiation and cannot be understood as indicating or implying relative importance.

[0129] In the description of the present embodiment, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set", "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present embodiment can be understood according to the specific circumstances.

[0130] While the application has been illustrated and described in connection with certain preferred embodiments thereof, it will be readily apparent to those of ordinary skill in the art that various changes in form and detail can be made therein without departing from the spirit and scope of the application. It is intended to encompass all such changes and alterations in the details thereof.

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.

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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