Oil level observation auxiliary device, application and oil level measurement method

Abstract

The present invention discloses an oil level observation auxiliary device, application and oil level measurement method, and relates to the field of liquid level measurement technology. The oil level observation auxiliary device includes a metal expander and a protective shell, the protective shell is provided with a measuring sensor, the protective shell is provided with an inner wall parallel to the expansion and contraction direction of the metal expander, the end of the metal expander is provided with a detection top plate, the side of the detection top plate is provided with a slide that moves along the inner wall, both ends of the slide are provided with a raised portion, and also includes a weight compensation mechanism, the weight compensation mechanism includes a constant force spring, and the constant force spring is connected to a traction rope. The application of the oil level observation auxiliary device includes the application of the oil level observation auxiliary device in the oil level observation of an oil-immersed current transformer. The oil level measurement method calculates the oil level of the oil-immersed current transformer according to a formula. The oil level observation auxiliary device, application and oil level measurement method can directly know the oil level of the oil from the terminal, which has the beneficial effects of saving manpower and accurate data.

Description

Technical Field

[0001] The present invention relates to the technical field of liquid level measurement, and in particular to an oil level observation auxiliary device, an application and an oil level measurement method. Background Art

[0002] Oil-immersed current transformer is an important primary equipment in substation and an important component of relay protection device in substation. The oil level of current transformer in substation needs to be observed regularly to ensure that the oil level of current transformer is normal and guarantee the normal operation of substation.

[0003] The oil level of the existing current transformer is observed through an observation window made of organic glass. It can be observed clearly at the beginning. As the operation time increases, the observation window is covered with dust and the organic glass ages, which makes it impossible to accurately observe the actual oil level of the current transformer, which brings hidden dangers to the stable operation of the current transformer. In addition, the means of observing the oil level of the current transformer are single, and the inspectors need to work on site in person. The inspection efficiency is low, which increases the workload of the inspectors.

[0004] Therefore, the prior art needs to be improved. Summary of the invention

[0005] The technical problem to be solved by the present invention is that the means for observing the oil level data of the current transformer in the prior art is single and the observation of the oil level data is limited after a long time. The purpose is to provide an oil level observation auxiliary device, application and oil level measurement method, which adopts corresponding technical means and has the beneficial effects of saving manpower and accurate data.

[0006] The present invention is achieved through the following technical solutions:

[0007] An oil level observation auxiliary device comprises a metal expander connected to an oil pipe or an oil tank, and a protective shell arranged outside the metal expander, wherein the protective shell is provided with a measuring sensor.

[0008] The protective shell is provided with an inner wall parallel to the expansion and contraction direction of the metal expander, a detection top plate is provided at the end of the metal expander, a sliding piece moving along the inner wall is provided on the side of the detection top plate, and both ends of the sliding piece are provided with a warping portion, and the measuring sensor detects the displacement change of the end face of the detection top plate and transmits the displacement change data to the terminal.

[0009] It also includes a weight compensation mechanism, which includes a constant force spring, the constant force spring is connected to a traction rope, the traction rope is connected to the detection top plate, and the traction force of the constant force spring is less than the gravity of the detection top plate.

[0010] Furthermore, in the present invention, the sliding sheet is provided with a groove on one side close to the inner wall, and a roller rolling on the inner wall is provided in the groove.

[0011] Furthermore, in the present invention, the above-mentioned sliding sheet has two groups of symmetrical rollers, one group of rollers is located on the upper side of the detection top plate, and the other group of rollers is located on the lower side of the detection top plate.

[0012] Furthermore, in the present invention, the side wall of the above-mentioned detection top plate is provided with a mounting hole, a spring and a telescopic rod pushed by the spring are arranged in the mounting hole, the telescopic rod is connected to the sliding plate, the telescopic rod is provided with a limiting groove, and the mounting hole is provided with a sliding block sliding along the limiting groove.

[0013] Furthermore, in the present invention, a drum and a mounting shaft passing through the drum are arranged inside the weight compensation mechanism, the constant force spring is installed inside the drum, the constant force spring is sleeved on the mounting shaft, and the traction rope is wound around the drum.

[0014] Furthermore, in the present invention, the difference between the traction force of the constant force spring and the gravity of the detection top plate is no more than 5 Newtons.

[0015] Furthermore, in the present invention, at least two weight compensation mechanisms are provided, and the weight compensation mechanisms are evenly distributed around the center of the detection top plate.

[0016] Furthermore, in the present invention, a wireless transmission module is provided on the top of the protective shell, the wireless transmission module is electrically connected to the measuring sensor and the terminal, and the terminal is provided with a normal oil level indicator light and an abnormal oil level indicator light.

[0017] The invention discloses an oil level observation auxiliary device and its application in oil level observation of oil-immersed current transformer.

[0018] An oil level measurement method, comprising the above-mentioned oil level observation auxiliary device, further comprising the following method:

[0019] Determine the distance X1 between the detection top plate and the measuring sensor at the highest oil level; determine the distance X2 between the detection top plate and the measuring sensor at the lowest oil level; during the operation of the oil-immersed current transformer, measure the distance X3 between the detection top plate and the measuring sensor through the measuring sensor; calculate the oil level K of the oil-immersed current transformer according to the formula, where the formula is K=X2-X3.

[0020] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0021] The present invention provides an oil level observation auxiliary device, which responds to the changes in oil through a metal expander. When there is more oil, the metal expander will expand and the height of the metal expander will become higher; when there is less oil, the metal expander will shrink and the height of the metal expander will become shorter. The measuring sensor can directly collect the displacement changes of the top plate of the top detection plate of the metal expander, and then transmit the data of the displacement changes to the terminal. The staff can directly know the oil level of the oil from the terminal without going to the site to collect data, which improves the efficiency of data collection and has the advantage of saving manpower. In addition, since the measuring sensor is installed on the outside of the metal expander, the measuring sensor will not be contaminated by the oil, and the aging of the measuring sensor will not affect the stable operation of the current transformer. The measuring sensor is wrapped by a protective shell, so the measuring sensor can work normally even if it is used for a long time, and has a long service life.

[0022] The present invention uses the oil level observation auxiliary device to observe the oil level of the oil-immersed current transformer, monitors the oil level data in real time, and ensures that the oil-immersed current transformer can operate stably.

[0023] The present invention also provides an oil level measurement method, which uses an oil level observation auxiliary device. The measurement sensor can directly collect the displacement changes of the top detection plate at the top of the metal expander, and then transmit the data of the displacement changes to the terminal, which is convenient for staff to obtain oil level data and has a good use effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] In order to more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and should not be regarded as limiting the scope. For those of ordinary skill in the art, other relevant drawings can be obtained based on these drawings without creative work. In the drawings:

[0025] Figure 1 A schematic diagram of the internal structure of an oil level observation auxiliary device according to an embodiment of the present invention;

[0026] Figure 2 A schematic diagram of the internal structure of another oil level observation auxiliary device according to an embodiment of the present invention;

[0027] Figure 3 A schematic diagram of the internal structure of a weight compensation mechanism according to an embodiment of the present invention;

[0028] Figure 4 is a schematic diagram of a terminal according to an embodiment of the present invention;

[0029] Figure 5 is a schematic diagram of a spring and a telescopic rod according to an embodiment of the present invention;

[0030] Figure 6 Schematic diagram of the control principle of the oil level observation auxiliary device according to an embodiment of the present invention.

[0031] Markings and corresponding parts names in the accompanying drawings: 1-metal expander, 2-protective shell, 201-inner wall, 3-measuring sensor, 4-detection top plate, 401-sliding plate, 402-lifting part, 403-roller, 404-mounting hole, 4041-slider, 405-spring, 406-telescopic rod, 4061-limiting groove, 5-weight compensation mechanism, 501-constant force spring, 502-traction rope, 503-roller, 504-mounting shaft, 6-terminal, 601-normal oil level indicator light, 602-abnormal oil level indicator light, 603-display screen, 604-control processing module, 605-sound alarm, 606-wireless transmission module. DETAILED DESCRIPTION

[0032] In order to make the purpose, technical scheme and advantages of the present invention clearer, the present invention is further described in detail below in conjunction with the embodiments and drawings. The schematic implementation mode of the present invention and its description are only used to explain the present invention and are not intended to limit the present invention. The following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present invention.

[0033] It should be noted that similar numbers and letters represent similar items in the following figures, so once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. In addition, the use of terms such as "horizontal", "vertical", etc. does not mean that the components are required to be absolutely horizontal or vertical, but can be slightly tilted. In the description of the embodiments of the present invention, it should also be noted that unless otherwise clearly specified and limited, the use of terms such as "set", "install", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0034] Embodiment 1, combination Figure 1-Figure 4 As shown, an oil level observation auxiliary device according to an embodiment of the present invention is shown, and the specific structure is described as follows.

[0035] Please refer to Figure 1As shown, the oil level observation auxiliary device of this embodiment is mainly composed of five parts: a metal expander 1, a protective shell 2, a measuring sensor 3, a detection top plate 4 and a weight compensation mechanism 5, wherein the metal expander 1 is used to feedback the height change of the oil level, the detection top plate 4 is used to feedback the height change of the top of the metal expander 1, the measuring sensor 3 is used to measure the displacement change of the detection top plate 4, the protective shell 2 is used to protect the internal metal expander 1 and the measuring sensor 3, and the weight compensation mechanism 5 is used to compensate for the weight of the detection top plate 4 to avoid affecting the expansion and contraction of the metal expander 1.

[0036] Further, combined with Figure 1 As shown, the metal expander 1 directly adopts the corrugated expander in the prior art, and the metal expander 1 is installed on the oil pipe or oil tank that needs to be detected. After installation and debugging, the metal expander 1 can respond to the oil level changes in the oil pipe or oil tank. When the oil level rises, the metal expander 1 rises accordingly, and when the oil level drops, the metal expander 1 drops accordingly.

[0037] In some implementations of this embodiment, the protective shell 2 is formed by welding metal plates, and anti-rust paint is applied on the surface of the protective shell 2 to delay rust. The protective shell 2 is cylindrical in shape, covering the outside of the metal expander 1, and the protective shell 2 wraps the metal expander 1. The measuring sensor 3 adopts an ultrasonic ranging sensor in the prior art, and the measuring sensor 3 is installed on the top of the protective shell 2, and the measuring end of the measuring sensor 3 is aligned with the metal expander 1 below.

[0038] It should be noted that the protective shell 2 protects the internal measuring sensor 3 and the metal expander 1, thereby preventing the measuring sensor 3 and the metal expander 1 from being accelerated by wind and sun, and prolonging their service life.

[0039] Further, combined with Figure 1 As shown, the top of the metal expander 1 may be tilted or partially sunken after long-term use, resulting in inaccurate measurement. Therefore, a detection top plate 4 is directly placed and installed on the top of the metal expander 1. The contact between the detection top plate 4 and the top of the metal expander 1 is not fixed, and it can be suitable for different metal expanders 1. The measuring end of the measuring sensor 3 is aligned with the detection top plate 4 on the top of the metal expander 1 below, and the displacement change of the detection top plate 4 is the oil level change of the oil. The detection top plate 4 can be placed directly on the top of the metal expander 1 without the need for connection processing, and can be directly used for the metal expander 1 of the prior art. It is more convenient to use and is suitable for almost all metal expanders 1.

[0040] Furthermore, combined Figure 1As shown, in order to prevent the detection top plate 4 from tilting during ascent or descent, the metal expander 1 is telescoped in the vertical direction, and the inner wall 201 of the protective shell 2 is also vertical, and the telescopic direction of the inner wall 201 and the metal expander 1 are parallel. A slide 401 is fixedly installed on the side of the detection top plate 4, and the upper end of the slide 401 exceeds the top surface of the detection top plate 4, and the lower end of the slide 401 exceeds the bottom surface of the detection top plate 4. The slide 401 can be evenly installed in four or six pieces. Since the slide 401 slides against the inner wall 201, the detection top plate 4 always maintains a horizontal state. No matter where the top surface of the detection top plate 4 is detected, the height of the oil level can be reflected more accurately, and the measurement is more accurate.

[0041] And, combined with Figure 1 The upper and lower ends of the sliding sheet 401 are both configured as a tilting portion 402 , and the tilting portion 402 tilts upward compared to the inner wall 201 , thereby ensuring that the sliding sheet 401 can slide smoothly.

[0042] It should be noted that in order to reduce the influence of the friction between the sliding piece 401 and the inner wall 201 on the expansion and contraction of the metal expander 1, as Figure 2 As shown, two grooves are provided on the slide 401, and rollers 403 are installed in the grooves. One slide 401 is installed with two sets of symmetrical rollers 403, one set of rollers 403 is located on the upper side of the detection top plate 4, and the other set of rollers 403 is located on the lower side of the detection top plate 4. The rolling of the rollers 403 on the inner wall 201 replaces the sliding of the slide 401 on the inner wall 201, thereby reducing friction and achieving better use effect.

[0043] In some implementations of this embodiment, since the detection top plate 4 is equipped with a slide 401 and a roller 403, it has a certain weight, which easily affects the lifting and lowering of the metal expander 1. In order to reduce the influence of the weight of the detection top plate 4 on the metal expander 1, a weight compensation mechanism 5 is installed. Figure 1 , Figure 2 and Figure 3 As shown, the weight compensation mechanism 5 has a shell, which is fixedly connected to the top wall of the protective shell 2. A mounting shaft 504 is installed inside the weight compensation mechanism 5. The constant force spring 501 adopts a constant force coil spring. The constant force spring 501 and the roller 503 are also sleeved on the mounting shaft 504, and the roller 503 can rotate around the mounting shaft 504. One end of the constant force spring 501 is fixedly connected to the mounting shaft 504, and the other end of the constant force spring 501 is fixedly connected to the roller 503. When the roller 503 is rotated by an external force applied thereto, the constant force spring 501 is tightened. When the external force is released, the tightened constant force spring 501 drives the roller 503 to rotate in the opposite direction.

[0044] like Figure 5As shown, in order to allow the detection top plate 4 to slide up and down in the protective shell 2 with different inner diameters, the side wall of the detection top plate 4 is provided with a mounting hole 404 extending horizontally inward, and the telescopic rod 406 and the mounting hole 404 can both be cylindrical, which is convenient for processing. The telescopic rod 406 is inserted into the interior of the mounting hole 404. A spring 405 is also installed in the mounting hole 404, one end of the spring 405 is pressed against the bottom of the mounting hole 404, and the other end of the spring 405 is pressed against the end face of the telescopic rod 406. The spring 405 is in a compressed state and can push the telescopic rod 406 outward. The telescopic rod 406 is fixedly connected to the slide 401, and even if the protective shell 2 has different inner diameters, it can be pressed against the protective shell 2 under the action of the spring 405, and the scope of application is wider.

[0045] like Figure 5 As shown, long strip-shaped limiting grooves 4061 are provided at the top and bottom of the telescopic rod 406, and the direction of the limiting grooves 4061 is parallel to the telescopic rod 406. Two sliders 4041 are fixedly connected to the wall near the end of the mounting hole 404, and the two sliders 4041 are respectively inserted into the two limiting grooves 4061. The sliders 4041 can only slide along the limiting grooves 4061, thereby limiting the forward and backward travel of the telescopic rod 406, and also preventing the telescopic rod 406 from rotating, and the use effect is better.

[0046] Further, combined with Figure 1 , Figure 2 and Figure 3 As shown, the traction rope 502 is wound on the drum 503, and one end of the traction rope 502 is away from the drum 503. Since the traction force of the constant force spring 501 is less than the gravity of the detection top plate 4, when the metal expander 1 contracts, the detection top plate 4 will also fall, and when the metal expander 1 expands, it rises against the detection top plate 4. The constant force spring 501 offsets part of the weight of the detection top plate 4 and hardly affects the rise and fall of the metal expander 1.

[0047] It should be noted that if the overall gravity of the top plate 4 is 50 Newtons, the traction provided by all the traction ropes 502 driven by all the constant force springs 501 is 90%-99% of the gravity of the top plate 4, that is, the traction of the traction ropes 502 is 45 Newtons to 49.5 Newtons, preferably 48 Newtons. Or if the overall gravity of the top plate 4 is 100 Newtons, the difference between the combined force of the traction provided by all the traction ropes 502 driven by all the constant force springs 501 and the gravity of the top plate 4 is 5 Newtons to 1 Newton, that is, the traction of the traction ropes 502 is 95 Newtons to 99 Newtons, preferably 96 Newtons.

[0048] Furthermore, combined Figure 1 and Figure 2 As shown, in this embodiment, four weight compensation mechanisms 5 are installed. The weight compensation mechanisms 5 are evenly distributed around the center of the detection top plate 4, the force is evenly applied, and the structural design is reasonable.

[0049] In some implementations of this embodiment, Figure 1 and Figure 4 As shown, a wireless transmission module 606 is installed on the top of the protective shell 2, and the wireless transmission module 606 and the measuring sensor 3 are connected by a wire. In addition, a terminal 6 is installed in the duty room of the staff, and the terminal 6 can use a computer in the prior art. A normal oil level indicator 601 and an abnormal oil level indicator 602, a display screen 603 and an audible alarm 605 are installed on the surface of the terminal 6. A control processing module 604 and a wireless transmission module 606 are also installed, and the two wireless transmission modules 606 establish a communication connection. A lithium battery or a 220V circuit is used as a power source to power the terminal 6.

[0050] It should be noted that the wireless transmission module 606, measurement sensor 3, control processing module 604 and other electronic components in this embodiment are all universal standard parts or components known to technical personnel in this field, and their structures and principles can be known to technical personnel in this field through technical manuals or through conventional experimental methods.

[0051] Embodiment 2, the embodiment of the present invention provides an application method, which uses the oil level observation auxiliary device in Embodiment 1 to observe the oil level of an oil-immersed current transformer, thereby eliminating the oil safety hazard of the oil-immersed current transformer.

[0052] Embodiment 3: This embodiment provides an oil level measurement method, which adopts the oil level observation auxiliary device in Embodiment 1.

[0053] It also includes the following method: after installation, first measure the distance X1 between the top plate 4 and the measuring sensor 3 at the highest oil level detection point, and measure the distance X2 between the top plate 4 and the measuring sensor 3 at the lowest oil level detection point, and store the data of X1 and X2 inside the control processing module 604.

[0054] Combination Figure 6 As shown, during the operation of the oil-immersed current transformer, the measuring sensor 3 can work in real time or once every period of time (for example, 30 seconds). The measuring sensor 3 measures the distance X3 between the detection top plate 4 and the measuring sensor 3; and transmits X3 to the control processing module 604 through the wireless transmission module 606. The control processing module 604 calculates the oil level K of the oil-immersed current transformer according to the edited formula K=X2-X3.

[0055] X1 and X2 are boundary values. When X1≤X3≤X2, it indicates that the oil level is in a normal state. The control processing module 604 controls the normal oil level indicator light 601 to light up, the abnormal oil level indicator light 602 to turn off, and displays the oil level value (K value) on the display screen 603. When X1>X3 or X3>X2, it indicates that the oil level is in a normal state. The control processing module 604 controls the normal oil level indicator light 601 to turn off, the abnormal oil level indicator light 602 to light up, and controls the sound alarm 605 to sound an alarm.

[0056] In summary, the present invention provides an oil level observation auxiliary device, which includes a metal expander 1 connected to an oil pipe or an oil tank, and a protective shell 2 covered on the outside of the metal expander 1, the protective shell 2 is provided with a measuring sensor 3, the protective shell 2 is provided with an inner wall 201 parallel to the expansion and contraction direction of the metal expander 1, the end of the metal expander 1 is provided with a detection top plate 4, the side of the detection top plate 4 is provided with a slide 401 moving along the inner wall 201, both ends of the slide 401 are provided with a tilting portion 402, the measuring sensor 3 detects the displacement change of the top surface of the detection top plate 4, and transmits the displacement change data to the terminal 6, and also includes a weight compensation mechanism 5, the weight compensation mechanism 5 includes a constant force spring 501, the constant force spring 501 is connected to a traction rope 502, the traction rope 502 is connected to the detection top plate 4, and the traction force of the constant force spring 501 is less than the gravity of the detection top plate 4. The slide 401 is provided with a groove on the side close to the inner wall 201, and a roller 403 rolling on the inner wall 201 is provided in the groove. A slide 401 has two groups of symmetrical rollers 403, one group of rollers 403 is located on the upper side of the detection top plate 4, and the other group of rollers 403 is located on the lower side of the detection top plate 4. The side wall of the detection top plate 4 is provided with a mounting hole 404, and a spring 405 and a telescopic rod 406 pushed by the spring 405 are arranged in the mounting hole 404, the telescopic rod 406 is connected to the slide 401, the telescopic rod 406 is provided with a limit groove 4061, and the mounting hole 404 is provided with a slider 4041 sliding along the limit groove 4061. The inside of the weight compensation mechanism 5 is provided with a roller 503 and a mounting shaft 504 passing through the roller 503, the constant force spring 501 is installed inside the roller 503, the constant force spring 501 is sleeved on the mounting shaft 504, and the traction rope 502 is wound around the roller 503. The difference between the traction force of the constant force spring 501 and the gravity of the detection top plate 4 is not more than 5 Newtons. At least two weight compensation mechanisms 5 are provided, and the weight compensation mechanisms 5 are evenly distributed around the center of the detection top plate 4. A wireless transmission module 606 is provided on the top of the protection shell 2, and the wireless transmission module 606 is electrically connected to the measurement sensor 3 and the terminal 6. The terminal 6 is provided with a normal oil level indicator light 601 and an abnormal oil level indicator light 602.

[0057] The present invention also provides an application of an oil level observation auxiliary device, and the application of the oil level observation auxiliary device in the oil level observation of an oil-immersed current transformer. The present invention also provides an oil level measurement method, which includes an oil level observation auxiliary device, and also includes the following method: determining the distance X1 between the detection top plate 4 and the measurement sensor 3 at the highest oil level; determining the distance X2 between the detection top plate 4 and the measurement sensor 3 at the lowest oil level; during the operation of the oil-immersed current transformer, measuring the distance X3 between the detection top plate 4 and the measurement sensor 3 by the measurement sensor 3; calculating the oil level K of the oil-immersed current transformer according to a formula, wherein the formula is K=X2-X3.

[0058] Therefore, the oil level observation auxiliary device, application and oil level measurement method provided by the embodiments of the present invention have the beneficial effects of saving manpower and providing accurate data.

[0059] The specific implementation methods described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An oil level observation auxiliary device, characterized in that: The invention comprises a metal expander (1) connected to an oil pipe or an oil tank, and a protective shell (2) arranged outside the metal expander (1), wherein the protective shell (2) is provided with a measuring sensor (3). The protective shell (2) is provided with an inner wall (201) parallel to the expansion and contraction direction of the metal expander (1); a detection top plate (4) is provided at the end of the metal expander (1); a sliding plate (401) moving along the inner wall (201) is provided on the side of the detection top plate (4); both ends of the sliding plate (401) are provided with a raised portion (402); the measuring sensor (3) detects the displacement change of the end surface of the detection top plate (4) and transmits the displacement change data to the terminal (6); The apparatus further comprises a weight compensation mechanism (5), wherein the weight compensation mechanism (5) comprises a constant force spring (501), wherein the constant force spring (501) is connected to a traction rope (502), wherein the traction rope (502) is connected to the detection top plate (4), and wherein the traction force of the constant force spring (501) is less than the gravity of the detection top plate (4). The difference between the traction force of the constant force spring (501) and the gravity of the detection top plate (4) is no more than 5 Newtons.

2. The oil level observation auxiliary device according to claim 1, characterized in that: The sliding sheet (401) is provided with a groove on one side close to the inner wall (201), and a roller (403) rolling on the inner wall (201) is arranged in the groove.

3. The oil level observation auxiliary device according to claim 2, characterized in that: One of the slide plates (401) has two groups of symmetrical rollers (403), one group of rollers (403) is located on the upper side of the detection top plate (4), and the other group of rollers (403) is located on the lower side of the detection top plate (4).

4. The oil level observation auxiliary device according to claim 3, characterized in that: The side wall of the detection top plate (4) is provided with a mounting hole (404), a spring (405) and a telescopic rod (406) pushed by the spring (405) are arranged in the mounting hole (404), the telescopic rod (406) is connected to the sliding sheet (401), the telescopic rod (406) is provided with a limiting groove (4061), and the mounting hole (404) is provided with a sliding block (4041) sliding along the limiting groove (4061).

5. The oil level observation auxiliary device according to claim 1, characterized in that: The weight compensation mechanism (5) is provided with a roller (503) and a mounting shaft (504) passing through the roller (503), the constant force spring (501) is installed inside the roller (503), the constant force spring (501) is sleeved on the mounting shaft (504), and the traction rope (502) is wound around the roller (503).

6. The oil level observation auxiliary device according to claim 1, characterized in that: At least two weight compensation mechanisms (5) are provided, and the weight compensation mechanisms (5) are evenly distributed around the center of the detection top plate (4).

7. The oil level observation auxiliary device according to claim 1, characterized in that: A wireless transmission module (606) is provided on the top of the protective shell (2); the wireless transmission module (606) is electrically connected to the measurement sensor (3) and the terminal (6); and the terminal (6) is provided with a normal oil level indicator light (601) and an abnormal oil level indicator light (602).

8. Use of the oil level observation auxiliary device of claim 1 in oil level observation of an oil-immersed current transformer.

9. An oil level measurement method, characterized in that: The oil level observation auxiliary device as claimed in claim 1 further comprises the following method: Determine the distance X1 between the detection top plate (4) and the measuring sensor (3) at the highest oil level; determine the distance X2 between the detection top plate (4) and the measuring sensor (3) at the lowest oil level; during the operation of the oil-immersed current transformer, measure the distance X3 between the detection top plate (4) and the measuring sensor (3) by the measuring sensor (3); calculate the oil level K of the oil-immersed current transformer according to a formula, wherein the formula is K=X2-X3.

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