A leak testing method for secondary gas pressure of oil-immersed power transformer

Abstract

The present invention discloses a method for testing the secondary gas pressure of an oil-immersed power transformer, and relates to the technical field of transformers. The method for testing the secondary gas pressure of an oil-immersed power transformer is implemented by a leakage testing device for the secondary gas pressure of an oil-immersed power transformer; the leakage testing device for the secondary gas pressure of an oil-immersed power transformer comprises a bracket assembly, a storage tank is fixedly arranged on the inner side of the bracket assembly, a transformer oil input pipe is fixedly arranged on the left side of the storage tank, and a pressure relief pipe is fixedly arranged on the right side of the storage tank, a dual driving mechanism is commonly arranged on the top, inside and bottom of the storage tank, and a dual pressurizing mechanism is arranged on the top of the inner cavity of the storage tank. The present invention can complete the hydraulic oil adding operation of the hydraulic oil tank more quickly, thereby shortening the time required for adding the hydraulic oil, improving the overall efficiency of the hydraulic oil tank leakage testing, reducing the cost of industrialized production, and being more suitable for industrialized production.

Description

Technical Field

[0001] The invention relates to the technical field of transformers, and in particular to a secondary gas pressure leakage testing method for an oil-immersed power transformer. Background Art

[0002] Oil leakage of oil-immersed power transformers is a common problem in their manufacturing and operation. All leakage weaknesses must be eliminated before the product leaves the factory to ensure safe and reliable operation of the product when it is hung on the grid.

[0003] The invention patent with patent application publication number CN 102589819 B discloses a secondary gas pressure leak test method for oil-immersed power transformers, which mainly conducts gas pressure leak tests on the transformer oil tank twice with different pressures and process methods to ultimately ensure that the transformer has no leakage. The invention method is simple in design and clear in principle. Through two leak tests, it can completely eliminate transformer oil leakage caused by strength defects of the oil tank weld, collision during assembly and transportation, or improper assembly of seals. The leak test has good effect, low cost, and is safe and reliable.

[0004] However, technicians in this field found that the above method still has some disadvantages when they put it into practical use. The most obvious one is that after spraying the primer and topcoat, the technicians need to install the dried and tightened transformer body into the oil tank and tighten the tank edge, and then add transformer oil that is 70% of the weight of the drawing.

[0005] In the above process, due to the caliber limitation of the oil filling channel on the oil tank, it takes a long time to inject the transformer oil, which reduces the overall leak test efficiency and increases the industrial production cost, making it not suitable for industrial production.

[0006] Therefore, it is necessary to invent a leak testing method for the secondary gas pressure of an oil-immersed power transformer to solve the above problems. Summary of the invention

[0007] The object of the present invention is to provide a secondary gas pressure leak testing method for an oil-immersed power transformer to solve the problems raised in the above-mentioned background technology.

[0008] To achieve the above object, the present invention provides the following technical solutions: a method for testing the secondary gas pressure of an oil-immersed power transformer for leakage, the method for testing the secondary gas pressure of an oil-immersed power transformer for leakage is implemented by a device for testing the secondary gas pressure of an oil-immersed power transformer for leakage;

[0009] The secondary air pressure leak testing equipment of the oil-immersed power transformer includes a bracket assembly, a storage tank is fixedly arranged on the inner side of the bracket assembly, a transformer oil inlet pipe is fixedly arranged on the left side of the storage tank and a pressure relief pipe is fixedly arranged on the right side of the storage tank, a dual driving mechanism is commonly arranged on the top, inside and bottom of the storage tank, a dual pressurizing mechanism is arranged on the top of the inner cavity of the storage tank, a lifting oil supply mechanism is arranged on the bottom of the inner cavity of the storage tank, the dual pressurizing mechanism and the lifting oil supply mechanism are both transmission-connected with the dual driving mechanism, and two outer wall cleaning mechanisms are arranged on the lifting oil supply mechanism.

[0010] Preferably, the support assembly comprises a mounting collar, an inverted U-shaped support frame and a support base plate;

[0011] The mounting collar is fixedly sleeved on the outer bottom of the storage tank, the inverted U-shaped support frame is fixedly sleeved on the outer side of the mounting collar, two support base plates are provided, and the two support base plates are respectively fixedly disposed on both ends of the inverted U-shaped support frame.

[0012] Preferably, the dual drive mechanism comprises a drive motor, an upper drive shaft and a lower drive shaft;

[0013] The drive motor is fixedly arranged on the top of the storage tank, the upper drive shaft is located inside the storage tank and is transmission-connected to the drive motor, and the lower drive shaft is located at the bottom of the storage tank and is connected to the upper drive shaft via an overrunning clutch.

[0014] Preferably, the double boosting mechanism comprises a sealing plate and two boosting components, and the boosting components comprise a screw, a lifting plate and a sealing piston;

[0015] The sealing plate is sleeved on the outer side of the upper drive shaft and is connected to the upper drive shaft through a reciprocating thread on the outer side of the upper drive shaft. The outer wall of the sealing plate fits the inner wall of the storage tank. The screw penetrates the sealing plate and is threadedly connected to the sealing plate. The top of the sealing plate is rotatably nested in the top of the inner cavity of the storage tank through a bearing. A reciprocating thread is provided at the bottom of the outer side of the screw. The lifting plate is sleeved on the bottom of the outer side of the sealing plate. The lifting plate is connected to the screw through a reciprocating thread. The sealing piston is sleeved on the outer side of the screw and bonded to the bottom of the lifting plate.

[0016] Preferably, the lifting type oil supply mechanism comprises a driving plate and two oil supply assemblies, and the oil supply assemblies comprise an oil supply pipe, an end plate and an oil inlet opening;

[0017] The driving plate is sleeved on the outer side of the lower driving shaft and is connected to the lower driving shaft through a reciprocating thread. The oil supply pipe is fixedly penetrated on the driving plate, and its top end penetrates the bottom of the storage tank and is slidably set inside the storage tank. A limiting groove is set on the inner wall of the oil supply pipe, and a limiting slider is fixedly set on the outer side of the lifting plate. The limiting slider is slidably set on the inner side of the limiting groove. The end plate is slidably sleeved on the outer side of the screw and fixedly set on the top of the oil supply pipe. A plurality of oil inlet openings are provided, and the plurality of oil inlet openings are evenly opened at the top of the outer side of the oil supply pipe.

[0018] Preferably, the outer wall cleaning mechanism comprises an annular scraper and a mounting frame;

[0019] The annular scraper is slidably sleeved and arranged on the outside of the oil supply pipe, the mounting frame is fixedly arranged on the side of the annular scraper, and the top end of the mounting frame is fixedly connected to the storage tank.

[0020] Preferably, the secondary gas pressure leak testing method of the oil-immersed power transformer specifically comprises the following steps:

[0021] S1. After the transformer oil tank is sealed with a cover, it is subjected to the first gas leakage test. After the first gas leakage test is completed, it is subjected to pickling and phosphating treatment, and the primer and topcoat are sprayed, and then the dried and tightened transformer body is installed into the oil tank;

[0022] S2. During the spraying process of primer and topcoat, transformer oil is injected into the storage tank through the transformer oil inlet pipe, and then the transformer oil tank is moved to the position directly below the two lifting oil supply mechanisms;

[0023] S3, the driving motor drives the upper driving shaft to rotate counterclockwise, at which time the upper driving shaft drives the sealing plate to rise, and when the sealing plate rises, it drives the screw to rotate, so that the lifting plate reciprocates and rises outside the screw, and when the upper driving shaft rotates counterclockwise, it drives the lower driving shaft to rotate counterclockwise synchronously, and the lower driving shaft drives the driving plate to descend at this time, and when the driving plate descends, it drives the two oil supply pipes to descend synchronously, so that the bottom end of the oil supply pipe gradually descends to the inside of the transformer oil tank;

[0024] S4. When the oil supply pipe descends from the top of the transformer to the inside of the transformer, the transformer oil in the storage tank enters the oil supply pipe through the oil inlet opening. However, due to the obstruction of the lifting plate and the sealing piston, the transformer oil cannot be output through the oil supply pipe.

[0025] S5, when the drive plate descends to the lowest end of the reciprocating thread on the outer side of the lower drive shaft, the lifting plate and the sealing piston are located at the top of the inner side of the oil supply pipe. At this time, the lifting plate and the sealing piston cannot block the oil supply pipe again, and the transformer oil enters the transformer oil tank through the inside of the oil supply pipe;

[0026] S6, at this time, the driving motor drives the upper driving shaft to rotate clockwise. At this time, due to the limitation of the overrunning clutch, the lower driving shaft cannot rotate. When the upper driving shaft rotates clockwise, it drives the sealing plate to repeatedly descend. When the sealing plate descends, it drives the screw to continuously rotate. At this time, the screw drives the lifting plate and the sealing piston to repeatedly rise and fall inside the oil supply pipe, thereby pressurizing the transformer oil entering the oil supply pipe and accelerating the flow speed of the transformer oil inside the oil supply pipe;

[0027] S7. As the sealing plate continues to descend, when the horizontal position of the sealing plate is lower than the transformer oil inlet pipe and the pressure relief pipe, the sealing plate begins to pressurize the inner cavity of the storage tank during the subsequent descent process, thereby accelerating the speed at which the transformer oil enters the oil supply pipe;

[0028] S8, after all the transformer oil has been added, the drive motor drives the upper drive shaft to rotate counterclockwise again, so that the lower drive shaft drives the lifting oil feeding mechanism to reset. During the resetting process of the lifting oil feeding mechanism, the transformer oil remaining on the outer side of the oil feeding pipe is scraped off by the annular scraper and drips into the transformer oil tank;

[0029] S9. After the oil is filled, the transformer oil tank is sealed with a cover, and then hoisted into a vacuum drying room for vacuum drying. After vacuum drying, transformer oil is added again through the oil filling pipe on the transformer oil tank, and then the transformer oil tank is gasified for a second leak test. Transformers without leakage can be put into storage.

[0030] Technical effects and advantages of the present invention:

[0031] The present invention is provided with a dual driving mechanism, a dual pressurizing mechanism and a lifting oil supply mechanism, so that the dual driving mechanism is used to first drive the lifting oil supply mechanism, and then the lifting oil supply mechanism is lowered into the transformer oil tank, and the dual pressurizing mechanism is used to restrict the lifting oil supply mechanism at the same time to avoid splashing due to accidental oil supply during the descent, and then the dual driving mechanism is used to drive the dual pressurizing mechanism, so that the dual pressurizing mechanism increases the flow rate of the transformer oil inside the lifting oil supply mechanism and the speed at which the transformer oil inside the storage tank enters the lifting oil supply mechanism. Compared with the same type of device in the prior art, the present invention can complete the hydraulic oil tank hydraulic oil tank addition operation more quickly, thereby shortening the time required for hydraulic oil addition, improving the overall efficiency of hydraulic oil tank leak testing, reducing the cost of industrial production, and being more suitable for industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the overall front view structure of the present invention.

[0033] Figure 2 It is a schematic diagram of the overall front cross-sectional structure of the present invention.

[0034] Figure 3 It is a front cross-sectional structural schematic diagram of the dual drive mechanism of the present invention.

[0035] Figure 4 It is a front sectional structural schematic diagram of the lifting type oil supply mechanism of the present invention.

[0036] Figure 5 For the present invention Figure 4 A schematic diagram of the enlarged structure of part A.

[0037] In the figure: 1. bracket assembly; 11. mounting collar; 12. inverted U-shaped support frame; 13. support bottom plate; 2. storage tank; 3. transformer oil inlet pipe; 4. pressure relief pipe; 5. double drive mechanism; 51. drive motor; 52. upper drive shaft; 53. lower drive shaft; 6. double boost mechanism; 61. sealing plate; 62. screw; 63. lifting plate; 64. sealing piston; 7. lifting oil supply mechanism; 71. drive plate; 72. oil supply pipe; 73. end plate; 74. oil inlet opening; 8. outer wall cleaning mechanism; 81. annular scraper; 82. mounting frame. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] Example 1

[0040] The present invention provides Figure 1-5 A method for testing the secondary gas pressure of an oil-immersed power transformer for leakage is shown, and the method for testing the secondary gas pressure of an oil-immersed power transformer for leakage is implemented by a device for testing the secondary gas pressure of an oil-immersed power transformer for leakage;

[0041] The secondary air pressure leakage testing equipment of the oil-immersed power transformer includes a bracket assembly 1, a storage tank 2 is fixedly arranged on the inner side of the bracket assembly 1, a transformer oil inlet pipe 3 is fixedly arranged on the left side of the storage tank 2 and a pressure relief pipe 4 is fixedly arranged on the right side of the storage tank 2, a dual driving mechanism 5 is commonly arranged on the top of the storage tank 2, the inside of the storage tank 2 and the bottom of the storage tank 2, a dual pressurizing mechanism 6 is arranged on the top of the inner cavity of the storage tank 2, and a lifting oil supply mechanism 7 is arranged on the bottom of the inner cavity of the storage tank 2, the dual pressurizing mechanism 6 and the lifting oil supply mechanism 7 are both transmission-connected to the dual driving mechanism 5, and two outer wall cleaning mechanisms 8 are arranged on the lifting oil supply mechanism 7.

[0042] like Figure 2As shown, the bracket assembly 1 includes a mounting ring 11, an inverted U-shaped support frame 12 and a support base plate 13, wherein the mounting ring 11 is fixedly sleeved on the outer bottom of the storage tank 2, the inverted U-shaped support frame 12 is fixedly sleeved on the outer side of the mounting ring 11, and two support base plates 13 are provided, and the two support base plates 13 are respectively fixedly arranged at both ends of the inverted U-shaped support frame 12.

[0043] like Figure 3 As shown, the dual drive mechanism 5 includes a drive motor 51, an upper drive shaft 52 and a lower drive shaft 53, wherein the drive motor 51 is fixedly arranged on the top of the storage tank 2, the upper drive shaft 52 is located inside the storage tank 2 and is transmission-connected to the drive motor 51, and the lower drive shaft 53 is located at the bottom of the storage tank 2 and is connected to the upper drive shaft 52 through an overrunning clutch.

[0044] By setting the above structure, when the driving motor 51 drives the upper driving shaft 52 to rotate counterclockwise, the lower driving shaft 53 rotates synchronously, and when the driving motor 51 drives the upper driving shaft 52 to rotate clockwise, the lower driving shaft 53 does not rotate.

[0045] like Figure 3 , Figure 4 and Figure 5 As shown, the double boosting mechanism 6 includes a sealing plate 61 and two boosting components, and the boosting components include a screw 62, a lifting plate 63 and a sealing piston 64, wherein the sealing plate 61 is sleeved on the outer side of the upper drive shaft 52 and is transmission-connected to the upper drive shaft 52 through a reciprocating thread on the outer side of the upper drive shaft 52, the outer wall of the sealing plate 61 fits the inner wall of the storage tank 2, the screw 62 penetrates the sealing plate 61 and is threadedly connected to the sealing plate 61, the top of the sealing plate 61 is rotatably nested in the top of the inner cavity of the storage tank 2 through a bearing, a reciprocating thread is provided at the outer bottom of the screw 62, the lifting plate 63 is sleeved on the outer bottom of the sealing plate 61, the lifting plate 63 is transmission-connected to the screw 62 through a reciprocating thread, and the sealing piston 64 is sleeved on the outer side of the screw 62 and bonded to the bottom of the lifting plate 63.

[0046] By setting the above structure, when the sealing plate 61 descends, it drives the screw 62 to rotate, and the screw 62 drives the lifting plate 63 and the sealing piston 64 to repeatedly rise and fall. In addition, when the screw 62 descends, the pressure inside the storage tank 2 can be increased.

[0047] like Figure 3 and Figure 4As shown, the lifting oil supply mechanism 7 includes a driving plate 71 and two oil supply components, and the oil supply component includes an oil supply pipe 72, an end plate 73 and an oil inlet opening 74, wherein the driving plate 71 is sleeved and arranged on the outer side of the lower driving shaft 53, and is transmission-connected to the lower driving shaft 53 through a reciprocating thread, the oil supply pipe 72 is fixedly penetrated and arranged on the driving plate 71, and its top end penetrates the bottom of the storage tank 2 and is slidably arranged inside the storage tank 2, a limiting slide groove is arranged on the inner wall of the oil supply pipe 72, a limiting slider is fixedly arranged on the outer side of the lifting plate 63, and the limiting slider is slidably arranged on the inner side of the limiting slide groove, the end plate 73 is slidably sleeved and arranged on the outer side of the screw 62, and is fixedly arranged on the top end of the oil supply pipe 72, and a plurality of the oil inlet openings 74 are arranged, and the plurality of the oil inlet openings 74 are evenly opened at the top of the outer side of the oil supply pipe 72.

[0048] By setting the above structure, the oil supply pipe 72 can be driven to rise and fall synchronously when the driving plate 71 rises and falls, and the end plate 73 blocks the top of the oil supply pipe 72, so that the transformer oil can only enter the oil supply pipe 72 through the oil inlet opening 74.

[0049] like Figure 4 As shown, the outer wall cleaning mechanism 8 includes an annular scraper 81 and a mounting bracket 82, wherein the annular scraper 81 is slidably sleeved on the outside of the oil supply pipe 72, the mounting bracket 82 is fixedly arranged on the side of the annular scraper 81, and the top of the mounting bracket 82 is fixedly connected to the storage tank 2.

[0050] By setting the above structure, when the oil supply pipe 72 is reset, the annular scraper 81 scrapes off the transformer oil remaining on the outer side of the oil supply pipe 72 and makes it fall into the transformer oil tank, thereby reducing the waste of transformer oil.

[0051] Example 2

[0052] The secondary gas pressure leak testing method of the oil-immersed power transformer specifically comprises the following steps:

[0053] S1. After the transformer oil tank is sealed with a cover, it is subjected to the first gas leakage test. After the first gas leakage test is completed, it is subjected to pickling and phosphating treatment, and the primer and topcoat are sprayed, and then the dried and tightened transformer body is installed into the oil tank;

[0054] S2. During the primer and topcoat spraying process, transformer oil is injected into the storage tank 2 through the transformer oil inlet pipe 3, and then the transformer oil tank is moved to the bottom of the two lifting oil supply mechanisms 7;

[0055] S3, the driving motor 51 drives the upper driving shaft 52 to rotate counterclockwise, at which time the upper driving shaft 52 drives the sealing plate 61 to rise, and when the sealing plate 61 rises, it drives the screw 62 to rotate, so that the lifting plate 63 is lifted and lowered reciprocatingly on the outside of the screw 62, and when the upper driving shaft 52 rotates counterclockwise, it drives the lower driving shaft 53 to rotate counterclockwise synchronously, and the lower driving shaft 53 drives the driving plate 71 to descend, and when the driving plate 71 descends, it drives the two oil supply pipes 72 to descend synchronously, so that the bottom end of the oil supply pipe 72 gradually descends to the inside of the transformer oil tank;

[0056] S4. During the process of the oil supply pipe 72 descending from the top of the transformer to the inside of the transformer, the transformer oil in the storage tank 2 enters the inside of the oil supply pipe 72 through the oil inlet opening 74. However, due to the obstruction of the lifting plate 63 and the sealing piston 64, the transformer oil cannot be output through the oil supply pipe 72.

[0057] S5, when the drive plate 71 descends to the lowest end of the reciprocating thread on the outer side of the lower drive shaft 53, the lifting plate 63 and the sealing piston 64 are located at the top of the inner side of the oil supply pipe 72. At this time, the lifting plate 63 and the sealing piston 64 cannot block the oil supply pipe 72 again, and the transformer oil enters the transformer oil tank through the inside of the oil supply pipe 72;

[0058] S6, at this time, the driving motor 51 drives the upper driving shaft 52 to rotate clockwise. At this time, due to the limitation of the overrunning clutch, the lower driving shaft 53 cannot rotate. When the upper driving shaft 52 rotates clockwise, it drives the sealing plate 61 to repeatedly descend. When the sealing plate 61 descends, it drives the screw 62 to continuously rotate. At this time, the screw 62 drives the lifting plate 63 and the sealing piston 64 to repeatedly rise and fall inside the oil supply pipe 72, thereby pressurizing the transformer oil entering the oil supply pipe 72 and accelerating the flow speed of the transformer oil inside the oil supply pipe 72;

[0059] S7, as the sealing plate 61 continues to descend, when the horizontal position of the sealing plate 61 is lower than the transformer oil inlet pipe 3 and the pressure relief pipe 4, the sealing plate 61 begins to pressurize the inner cavity of the storage tank 2 during the subsequent descending process, thereby accelerating the speed at which the transformer oil enters the oil supply pipe 72;

[0060] S8, after all the transformer oil has been added, the driving motor 51 drives the upper driving shaft 52 to rotate counterclockwise again, so that the lower driving shaft 53 drives the lifting oil feeding mechanism 7 to reset. During the resetting process of the lifting oil feeding mechanism 7, the transformer oil remaining on the outer side of the oil feeding pipe 72 is scraped off by the annular scraper 81 and drips into the transformer oil tank;

[0061] S9. After the oil is filled, the transformer oil tank is sealed with a cover, and then hoisted into a vacuum drying room for vacuum drying. After vacuum drying, transformer oil is added again through the oil filling pipe on the transformer oil tank, and then the transformer oil tank is gasified for a second leak test. Transformers without leakage can be put into storage.

[0062] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for testing the secondary gas pressure of an oil-immersed power transformer for leakage, characterized in that: The oil-immersed power transformer secondary gas pressure leakage test method is implemented by oil-immersed power transformer secondary gas pressure leakage test equipment; The secondary gas pressure leakage test device of the oil-immersed power transformer comprises a support assembly (1), a storage tank (2) is fixedly arranged on the inner side of the support assembly (1), a transformer oil inlet pipe (3) is fixedly arranged through the left side of the storage tank (2), and a pressure relief pipe (4) is fixedly arranged through the right side of the storage tank (2), a dual driving mechanism (5) is commonly arranged on the top of the storage tank (2), inside the storage tank (2) and the bottom of the storage tank (2), a dual pressurizing mechanism (6) is arranged on the top of the inner cavity of the storage tank (2), and a lifting oil supply mechanism (7) is arranged on the bottom of the inner cavity of the storage tank (2), the dual pressurizing mechanism (6) and the lifting oil supply mechanism (7) are both transmission-connected to the dual driving mechanism (5), and the lifting oil supply mechanism (7) is provided with two outer wall cleaning mechanisms (8); The dual drive mechanism (5) comprises a drive motor (51), an upper drive shaft (52) and a lower drive shaft (53); The dual boosting mechanism (6) comprises a sealing plate (61) and two boosting components, wherein the boosting components comprise a screw (62), a lifting plate (63) and a sealing piston (64); The sealing plate (61) is sleeved and arranged on the outer side of the upper driving shaft (52), and is drivingly connected to the upper driving shaft (52) through a reciprocating thread on the outer side of the upper driving shaft (52); the screw (62) penetrates the sealing plate (61) and is threadedly connected to the sealing plate (61); The lifting type oil supply mechanism (7) comprises a driving plate (71) and two oil supply assemblies, wherein the oil supply assemblies comprise an oil supply pipe (72), an end plate (73) and an oil inlet opening (74); The driving plate (71) is sleeved on the outside of the lower driving shaft (53) and is drivingly connected to the lower driving shaft (53) via a reciprocating thread. The oil supply pipe (72) is fixedly penetrated on the driving plate (71), and its top end penetrates the bottom of the storage tank (2) and is slidably disposed inside the storage tank (2).

2. The method for testing the secondary gas pressure of an oil-immersed power transformer according to claim 1, characterized in that: The support assembly (1) comprises a mounting collar (11), an inverted U-shaped support frame (12) and a support base plate (13); The mounting collar (11) is fixedly sleeved on the outer bottom of the storage tank (2), the inverted U-shaped support frame (12) is fixedly sleeved on the outer side of the mounting collar (11), two support bottom plates (13) are provided, and the two support bottom plates (13) are respectively fixedly arranged at two ends of the inverted U-shaped support frame (12).

3. The method for testing the secondary gas pressure of an oil-immersed power transformer according to claim 2, characterized in that: The drive motor (51) is fixedly arranged on the top of the storage tank (2), the upper drive shaft (52) is located inside the storage tank (2) and is transmission-connected to the drive motor (51), and the lower drive shaft (53) is located at the bottom of the storage tank (2) and is connected to the upper drive shaft (52) via an overrunning clutch.

4. The method for testing the secondary gas pressure of an oil-immersed power transformer according to claim 3 is characterized in that: The outer wall of the sealing plate (61) is fitted with the inner wall of the storage tank (2); the top of the sealing plate (61) is rotatably nested in the top of the inner cavity of the storage tank (2) through a bearing; the outer bottom of the screw rod (62) is provided with a reciprocating thread; the lifting plate (63) is sleeved on the outer bottom of the sealing plate (61); the lifting plate (63) is transmission-connected with the screw rod (62) through the reciprocating thread; the sealing piston (64) is sleeved on the outer side of the screw rod (62) and is bonded to the bottom of the lifting plate (63).

5. The method for testing the secondary gas pressure of an oil-immersed power transformer according to claim 4 is characterized in that: A limiting groove is provided on the inner wall of the oil supply pipe (72), a limiting slider is fixedly provided on the outer side of the lifting plate (63), the limiting slider is slidably provided on the inner side of the limiting groove, the end plate (73) is slidably sleeved on the outer side of the screw rod (62), and is fixedly provided on the top of the oil supply pipe (72), and a plurality of oil inlet openings (74) are provided, and the plurality of oil inlet openings (74) are evenly opened on the outer top of the oil supply pipe (72).

6. A method for testing secondary gas pressure of an oil-immersed power transformer for leakage according to claim 5, characterized in that: The outer wall cleaning mechanism (8) comprises an annular scraper (81) and a mounting frame (82); The annular scraper (81) is slidably sleeved on the outside of the oil supply pipe (72), the mounting frame (82) is fixedly arranged on the side of the annular scraper (81), and the top end of the mounting frame (82) is fixedly connected to the storage tank (2).

7. A method for testing secondary gas pressure of an oil-immersed power transformer for leakage according to claim 6, characterized in that: The secondary gas pressure leak testing method of the oil-immersed power transformer specifically comprises the following steps: S1. After the transformer oil tank is sealed with a cover, it is subjected to the first gas leakage test. After the first gas leakage test is completed, it is subjected to pickling and phosphating treatment, and the primer and topcoat are sprayed, and then the dried and tightened transformer body is installed into the oil tank; S2. During the primer and topcoat spraying process, transformer oil is injected into the storage tank (2) through the transformer oil inlet pipe (3), and then the transformer oil tank is moved to the position directly below the two lifting oil supply mechanisms (7); S3, the driving motor (51) drives the upper driving shaft (52) to rotate counterclockwise, and the upper driving shaft (52) drives the sealing plate (61) to rise. When the sealing plate (61) rises, it drives the screw rod (62) to rotate, so that the lifting plate (63) is lifted and lowered reciprocatingly on the outside of the screw rod (62). When the upper driving shaft (52) rotates counterclockwise, it drives the lower driving shaft (53) to rotate counterclockwise synchronously. At this time, the lower driving shaft (53) drives the driving plate (71) to descend. When the driving plate (71) descends, it drives the two oil supply pipes (72) to descend synchronously, so that the bottom end of the oil supply pipe (72) gradually descends to the inside of the transformer oil tank; S4, when the oil supply pipe (72) descends from the top of the transformer to the inside of the transformer, the transformer oil in the storage tank (2) enters the inside of the oil supply pipe (72) through the oil inlet opening (74), but due to the obstruction of the lifting plate (63) and the sealing piston (64), the transformer oil cannot be output through the oil supply pipe (72); S5, when the drive plate (71) descends to the lowest end of the reciprocating thread on the outer side of the lower drive shaft (53), the lifting plate (63) and the sealing piston (64) are located at the top of the inner side of the oil supply pipe (72), and at this time, the lifting plate (63) and the sealing piston (64) cannot seal the oil supply pipe (72) again, and the transformer oil enters the transformer oil tank through the inside of the oil supply pipe (72); S6, at this time, the driving motor (51) drives the upper driving shaft (52) to rotate clockwise. At this time, due to the limitation of the overrunning clutch, the lower driving shaft (53) cannot rotate. When the upper driving shaft (52) rotates clockwise, it drives the sealing plate (61) to repeatedly descend. When the sealing plate (61) descends, it drives the screw (62) to continuously rotate. At this time, the screw (62) drives the lifting plate (63) and the sealing piston (64) to repeatedly rise and fall inside the oil supply pipe (72), thereby pressurizing the transformer oil entering the inside of the oil supply pipe (72) and accelerating the flow speed of the transformer oil inside the oil supply pipe (72); S7, as the sealing plate (61) continues to descend, when the horizontal position of the sealing plate (61) is lower than the transformer oil inlet pipe (3) and the pressure relief pipe (4), the sealing plate (61) begins to pressurize the inner cavity of the storage tank (2) during the subsequent descending process, thereby accelerating the speed at which the transformer oil enters the oil supply pipe (72); S8, after all the transformer oil has been added, the driving motor (51) drives the upper driving shaft (52) to rotate counterclockwise again, thereby causing the lower driving shaft (53) to drive the lifting oil supply mechanism (7) to reset. During the resetting process of the lifting oil supply mechanism (7), the transformer oil remaining on the outer side of the oil supply pipe (72) is scraped off by the annular scraper (81) and drips into the transformer oil tank; S9. After the oil is filled, the transformer oil tank is sealed with a cover, and then hoisted into a vacuum drying room for vacuum drying. After vacuum drying, transformer oil is added again through the oil filling pipe on the transformer oil tank, and then the transformer oil tank is gasified for a second leak test. Transformers without leakage can be put into storage.

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