An accelerated thermal aging test device and method for oil-immersed transformer insulation pads

Abstract

The invention relates to the technical field of transformer testing, and in particular to an accelerated thermal aging test device and method for an insulating pad of an oil-immersed transformer, comprising a base plate, a support, an L-shaped box, a drive assembly, a test box, a support assembly and a pressure assembly. By optimizing and improving a seesaw structure, the insulating pad can be quickly immersed in or taken out of oil, and a dry and suitable installation environment is provided for a traditional pressure sensor, thereby broadening the temperature test range of the test. Meanwhile, a height-adjustable insulating pad support structure is provided, which can simulate the aging environment of the insulating pad at different depths and different positions, so that the test result is closer to the actual use condition, the accuracy of the test data is ensured, and the evaluation result of the actual service life and performance of the insulating pad by subsequent testers is improved.

Description

Technical Field

[0001] The invention relates to the technical field of transformer testing, in particular to an accelerated thermal aging testing device and method for an insulating pad of an oil-immersed transformer. Background Art

[0002] During the long-term operation of the transformer, the mechanical and insulation properties of the insulating spacers between the winding layers will gradually deteriorate due to the combined effects of thermal aging and mechanical aging, thereby reducing the winding's ability to resist short circuits. At present, the short-circuit resistance of the insulating spacers is only evaluated based on the initial performance parameters of the winding material. In actual applications, the insulation performance of the insulating spacers inside the transformer will be affected by the size of the preload pressure and the installation position.

[0003] During the traditional insulating pad aging test, since the current operating environment temperature of industrial pressure sensors is between -20 degrees Celsius and 85 degrees Celsius and is only suitable for dry environments, they cannot be immersed in high-temperature oil for use, and cannot cope with tests with aging temperatures exceeding 85 degrees Celsius, thereby limiting the test scope and reducing the accuracy of the test results; in addition, the traditional insulating pad aging test cannot test insulating pads in different installation positions, making the final test data inaccurate, which affects the testers' evaluation of the actual service life and performance of the insulating pads. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides an accelerated thermal aging test device and method for insulating pads of oil-immersed transformers. By optimizing and improving the seesaw structure, the insulating pads can be quickly immersed in oil or taken out, while providing a dry and suitable installation environment for traditional pressure sensors, broadening the temperature test range of the experiment, and providing a height-adjustable insulating pad support structure to simulate the aging environment of the insulating pads at different depths and different positions, so that the test results are closer to actual usage, ensuring the accuracy of the test data, and improving the subsequent testers' evaluation results on the actual service life and performance of the insulating pads.

[0005] The technical solution adopted by the present invention to solve the above technical problems is: an accelerated thermal aging test device for insulating pads of oil-immersed transformers, comprising a bottom plate and a support fixed to the upper end of the bottom plate, the upper end of the support is fixedly connected to an L-shaped box, a driving assembly is arranged inside the L-shaped box, the end of the L-shaped box away from the support is open and fixedly connected to a test box, a support assembly is fixedly installed at the bottom of the test box, the support assembly and the driving assembly are fixedly connected, and a pressure assembly is arranged above the support assembly;

[0006] A rectangular through slot is provided in the middle of the bottom of the test box;

[0007] The support assembly includes a first return frame, which is sealed and connected to the upper end of the rectangular through groove, a return groove is opened inside the first return frame, and a second return frame is slidably and sealably installed inside the return groove, and a support plate is sealed and connected to the upper end of the second return frame, and a loading unit is fixedly installed on the middle part of the upper end of the support plate, an L-shaped connecting rod is arranged on the side of the support plate close to the L-shaped box body, and a rectangular slide groove is opened inside the end of the L-shaped connecting rod facing the support plate, the end of the support plate is slidably installed in the rectangular slide groove, and an extrusion spring is arranged between the side wall of the rectangular slide groove and the end of the support plate, a sealing plate is fixedly installed on the lower end of the rectangular through groove, a pressure sensor is fixedly arranged in the middle part of the upper end of the sealing plate, a heat insulation film is arranged on the sealing plate outside the pressure sensor, and the upper end of the heat insulation film is fixedly connected to the lower end surface of the support plate.

[0008] Preferably, an anti-overflow plate is provided inside the end of the L-shaped box away from the support, and a rubber strip is fixedly installed in the middle of the upper end of the anti-overflow plate.

[0009] Preferably, the upper end surface of the end away from the support of the L-shaped box is rotatably connected to a cover plate through a torsion spring, a plurality of heating rods are arranged on the side wall of the cover plate close to the test box, a temperature monitor is arranged on the side wall of the cover plate away from the test box, and the temperature monitor and the heating rods are connected by electrical signals.

[0010] Preferably, the driving assembly includes a driving unit, which is arranged near the upper end of the L-shaped box, the lateral end of the driving unit is fixedly connected to the cover plate, the vertical end of the driving unit is connected to the driving plate, a rotating shaft is fixedly installed near the middle of the driving plate, the end of the rotating shaft is rotatably connected to the side wall of the L-shaped box, a gravity block is fixedly installed at the lower end of the end of the driving plate away from the rotating shaft, and the end of the driving plate close to the rotating shaft extends into the test box and is fixedly connected to an L-shaped connecting rod.

[0011] Preferably, the driving unit includes a driving motor, which is fixedly installed on the outer wall of the L-shaped box near the upper end, and the output shaft of the driving motor is fixedly connected to the driving shaft, and the driving shaft extends to the inside of the L-shaped box away from the end of the driving motor, and a No. 1 wire wheel is fixedly installed in the middle of the driving shaft, and a first traction line is wound around the No. 1 wire wheel, and the end of the first traction line is fixedly bolted to the side wall of the cover plate, and a No. 2 wire wheel is symmetrically installed on both sides of the No. 1 wire wheel, and a second traction line is wound around the second wire wheel, and the lower end of the second traction line is fixedly bolted to the upper end of the driving plate.

[0012] Preferably, a through slot is provided on the side wall of the L-shaped box body facing the cover plate, and guide wheels are symmetrically installed in the through slot.

[0013] Preferably, the loading unit comprises an internal threaded barrel, which is fixedly connected to the middle of the upper end surface of the support plate, a threaded rod is screwed on the inner side of the internal threaded barrel, a step block is fixedly connected to the upper end of the threaded rod, a placement groove is provided on the stepped end surface of the step block, and a handle is installed on the side wall of the step block.

[0014] Preferably, the pressure-applying assembly includes a slide plate, a strip slide groove is provided at the upper end of the test box near the edge, a slide plate is slidably arranged in the strip slide groove, cross bars are symmetrically installed between the opposite side walls of the slide plate, a tension spring is installed between the side wall of the slide plate away from the L-shaped box and the inner wall of the test box, a linkage rope is connected between the side wall of the slide plate close to the L-shaped box and the cover plate, an electric push rod is fixedly installed on the lower end surface of the slide plate, a push plate is fixedly connected to the lower end of the electric push rod, and a stepped pressure plate is fixedly connected to the proximal end of the push plate.

[0015] Preferably, the stepped pressing plate has a porous structure.

[0016] Preferably, the testing method of the accelerated thermal aging testing device for the insulation pad of the oil-immersed transformer comprises the following steps:

[0017] S1. The tester first holds the handle to drive the step block to rotate to the test height, then places the insulating pad to be tested into the placement slot on the step block, and then adds an appropriate amount of mineral insulating oil into the test box;

[0018] S2, start the driving assembly, drive the supporting assembly to move downward through the driving assembly and make the lower end of the supporting plate contact with the upper end of the pressure sensor, record the pressure sensor reading N1, at this time, the insulating pad in the slot on the step block is immersed in the mineral insulating oil, and the cover plate will cover the upper end of the test box to make the test box airtight, and the pressure assembly will move to the top of the step block;

[0019] S3, applying pressure to the insulating pad in the placement groove through the pressure component, recording the pressure sensor reading N2, then heating the mineral insulating oil around the insulating pad through the heating rod, and recording the heating time and heating temperature through the temperature monitor;

[0020] S4: After 100 hours, the pressure assembly and the driving assembly are reset, the tested insulating pad is manually taken out and its various performance indicators are tested, and then compared with the standard indicators, so as to obtain the aging condition of the insulating pad within 100 hours under the differential pressure of N2-N1.

[0021] Beneficial effects of the present invention:

[0022] 1. In the drive assembly, the drive unit can use the lever principle to drive the insulating pad to quickly immerse in the oil, and it is also convenient to take it out, which improves the test efficiency. During the test, the drive unit can drive the cover to seal the test box to avoid interference from other factors, more realistically simulate the situation inside the transformer, and ensure the accuracy of the test data;

[0023] 2. The sealing plate, the first return frame, the second return frame and the support plate provide a dry and suitable installation environment for the pressure sensor. At the same time, the thermal insulation film plays a certain role in thermal insulation, ensuring the stability of the pressure sensor during operation, broadening the temperature test range of the test, and thus improving the accuracy of the test results;

[0024] 3. In the support assembly, the loading unit is capable of adjusting the height of multiple insulating pads at the same time, thereby more accurately simulating the aging environment of the insulating pads at different depths and positions, making the test results closer to actual usage, ensuring the accuracy of the test data, and improving the subsequent testers' evaluation results on the actual service life and performance of the insulating pads. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0026] Figure 1 It is a three-dimensional structural schematic diagram of the present invention;

[0027] Figure 2 The present invention Figure 1 Bottom view of

[0028] Figure 3 It is a schematic diagram of the three-dimensional connection structure between the driving assembly and the supporting assembly in the present invention;

[0029] Figure 4 is a top view of the present invention;

[0030] Figure 5 The present invention Figure 4 AA-direction cross-sectional three-dimensional structure schematic diagram;

[0031] Figure 6 It is a schematic diagram of a partially cutaway three-dimensional connection structure between a driving board, a test box and a supporting assembly in the present invention;

[0032] Figure 7 The present invention Figure 6 A schematic diagram of the enlarged structure at B;

[0033] Figure 8 It is a schematic diagram of the three-dimensional connection structure between the test box and the pressure-applying assembly in the present invention.

[0034] In the figure:

[0035] 1. Bottom plate; 2. Support; 3. L-shaped box; 31. Anti-overflow plate; 32. Rubber strip; 33. Cover plate; 34. Heating rod; 35. Temperature monitor; 36. Through slot; 37. Guide wheel;

[0036] 4. driving assembly; 41. driving unit; 411. driving motor; 412. driving shaft; 413. first line wheel; 414. first traction line; 415. second line wheel; 416. second traction line;

[0037] 42. Rotating shaft; 43. Driving plate; 44. Gravity block; 5. Test box;

[0038] 6. Support assembly; 61. First return frame; 62. Second return frame; 63. Support plate;

[0039] 64, loading unit; 641, internal threaded cylinder; 642, threaded rod; 643, step block; 644, handle;

[0040] 65. L-shaped connecting rod; 66. extrusion spring; 67. sealing plate; 68. pressure sensor; 69. thermal insulation film;

[0041] 7. Pressure assembly; 71. Slide plate; 72. Tension spring; 73. Linkage rope; 74. Cross bar; 75. Electric push rod; 76. Push plate; 77. Step pressure plate. DETAILED DESCRIPTION

[0042] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0043] Embodiment 1:

[0044] See also Figures 1 to 7 , an accelerated thermal aging test device for insulating pads of oil-immersed transformers, comprising a base plate 1 and a support 2 fixed on the upper end of the base plate 1, an L-shaped box 3 is fixedly connected to the upper end of the support 2, a driving assembly 4 is arranged inside the L-shaped box 3, the end of the L-shaped box 3 away from the support 2 is open and fixedly connected to a test box 5, a support assembly 6 is fixedly installed at the bottom of the test box 5, and the support assembly 6 and the driving assembly 4 are fixedly connected.

[0045] An anti-overflow plate 31 is arranged inside the end of the L-shaped box 3 away from the support 2, and a rubber strip 32 is fixedly installed in the middle of the upper end of the anti-overflow plate 31. The upper end surface of the end of the L-shaped box 3 away from the support 2 is rotatably connected to a cover plate 33 through a torsion spring. A plurality of heating rods 34 are arranged on the side wall of the cover plate 33 close to the test box 5. A temperature monitor 35 is arranged on the side wall of the cover plate 33 away from the test box 5. The temperature monitor 35 and the heating rod 34 are connected by electrical signals. A through groove 36 is opened on the side wall of the L-shaped box 3 facing the cover plate 33, and guide wheels 37 are symmetrically installed in the through groove 36.

[0046] The driving assembly 4 includes a driving unit 41. The driving unit 41 is arranged near the upper end of the L-shaped box 3. The lateral end of the driving unit 41 is fixedly connected to the cover plate 33. The vertical end of the driving unit 41 is connected to a driving plate 43. A rotating shaft 42 is fixedly installed near the middle of the driving plate 43. The end of the rotating shaft 42 is rotatably connected to the side wall of the L-shaped box 3. A gravity block 44 is fixedly installed at the lower end of the end of the driving plate 43 away from the rotating shaft 42. The end of the driving plate 43 close to the rotating shaft 42 extends into the test box 5 and is fixedly connected to an L-shaped connecting rod 65.

[0047] The driving unit 41 includes a driving motor 411, and the driving motor 411 is fixedly installed on the outer wall of the L-shaped box 3 near the upper end. The output shaft of the driving motor 411 is fixedly connected to the driving shaft 412, and the driving shaft 412 extends to the inside of the L-shaped box 3 away from the end of the driving motor 411. A first wire wheel 413 is fixedly installed in the middle of the driving shaft 412, and a first traction line 414 is wound around the first wire wheel 413. The end of the first traction line 414 is fixedly bolted to the side wall of the cover plate 33. A second wire wheel 415 is symmetrically installed on both sides of the No. 1 wire wheel 413, and a second traction line 416 is wound around the second wire wheel 415. The lower end of the second traction line 416 is fixedly bolted to the upper end of the driving plate 43.

[0048] A rectangular through slot is provided in the middle of the bottom of the test box 5;

[0049] The support assembly 6 includes a first return frame 61, which is sealed and connected to the upper end of the rectangular through groove. A return groove is provided inside the first return frame 61, and a second return frame 62 is slidably and sealedly installed inside the return groove. A support plate 63 is sealed and connected to the upper end of the second return frame 62. A loading unit 64 is fixedly installed in the middle of the upper end of the support plate 63. An L-shaped connecting rod 65 is provided on the side of the support plate 63 close to the L-shaped box 3. A rectangular slide groove is provided inside the end of the L-shaped connecting rod 65 facing the support plate 63. The end of the support plate 63 is slidably installed in the rectangular slide groove, and an extrusion spring 66 is provided between the side wall of the rectangular slide groove and the end of the support plate 63. A sealing plate 67 is fixedly installed at the lower end of the rectangular through groove, and a pressure sensor 68 is fixedly provided in the middle of the upper end of the sealing plate 67. A heat insulation film 69 is provided on the sealing plate 67 outside the pressure sensor 68, and the upper end of the heat insulation film 69 is fixedly connected to the lower end surface of the support plate 63.

[0050] The loading unit 64 includes an internal threaded barrel 641, which is fixedly connected to the middle of the upper end surface of the support plate 63, a threaded rod 642 is screwed on the inner side of the internal threaded barrel 641, a step block 643 is fixedly connected to the upper end of the threaded rod 642, a placement groove is provided on the stepped end surface of the step block 643, and a handle 644 is installed on the side wall of the step block 643.

[0051] During the specific operation, the tester first places the oil-immersed transformer insulation pad accelerated thermal aging test device flat on the ground, then holds the handle 644 to drive the step block 643 and the threaded rod 642 to rotate, and the threaded rod 642 can rotate to move upward or downward on the internal threaded cylinder 641, thereby adjusting the step block 643 to a specified test height, and then places the insulation pad to be tested into the placement groove on the step block 643, and then adds a proper amount of mineral insulating oil into the test box 5;

[0052] The driving motor 411 is started, and the driving shaft 412, the first wire wheel 413, the first traction line 414, the second wire wheel 415 and the second traction line 416 are driven to rotate. At this time, the second wire wheel 415 will drive the second traction line 416 to reel in, thereby driving the end of the driving plate 43 equipped with the gravity block 44 to rotate upward. At the same time, the driving plate 43 rotates downward away from the end with the gravity block 44 and drives the L-shaped connecting rod 65 to move downward. Due to the arrangement of the rectangular slide groove and the extrusion spring 66, the L-shaped connecting rod 65 will also drive the support plate 63 and the loading unit 64 to move downward. The step block 643 is moved to immerse the insulating pad on the step surface thereof in the mineral insulating oil until the lower end of the support plate 63 contacts the upper end of the pressure sensor 68, and the indication N1 of the pressure sensor 68 is recorded. When the carrier unit 64 and the insulating pad are immersed in the mineral insulating oil, the liquid level of the mineral insulating oil will rise. At this time, the anti-overflow plate 31 can prevent the mineral insulating oil from overflowing, and the rubber strip 32 can play a certain role in limiting the rotation of the driving plate 43. When the driving plate 43 rotates downward to abut against the rubber strip 32, it indicates that it has rotated to the maximum limit.

[0053] During the rotation, the No. 1 wire wheel 413 will also drive the first traction wire 414 to unwind. At this time, the cover plate 33 will rotate to the upper end of the test box 5 under the reaction of the torsion spring and make the test box 5 airtight. At this time, the heating rod 34 will also be immersed in the mineral insulating oil. The mineral insulating oil around the insulating pad is heated by the heating rod 34, and the heating time and heating temperature are recorded by the temperature monitor 35.

[0054] Embodiment 2:

[0055] The technical solution is basically the same as that of the first embodiment, see Figure 1 , Figure 4 , Figure 5 as well as Figure 8The difference is that: a pressure assembly 7 is arranged above the support assembly 6, and the pressure assembly 7 includes a slide plate 71. A strip slide groove is opened at the upper end of the test box 5 near the edge, and a slide plate 71 is slidably arranged in the strip slide groove. A cross bar 74 is symmetrically installed between the opposite side walls of the slide plate 71, and a tension spring 72 is installed between the side wall of the slide plate 71 away from the L-shaped box body 3 and the inner wall of the test box 5. A linkage rope 73 is connected between the side wall of the slide plate 71 close to the L-shaped box body 3 and the cover plate 33. An electric push rod 75 is fixedly installed on the lower end surface of the slide plate 71, and a push plate 76 is fixedly connected to the lower end of the electric push rod 75. A stepped pressing plate 77 is fixedly connected to the proximal end of the push plate 76, and the stepped pressing plate 77 is present in a porous structure.

[0056] It should be noted that, in this embodiment, the tension spring 72 is in a tensioned state at the initial position.

[0057] When the cover plate 33 is rotated to the upper end of the test box 5, the linkage rope 73 will shrink, and the reaction force of the tension spring 72 will drive the slide plate 71, the cross bar 74, the electric push rod 75, the push plate 76 and the step pressure plate 77 to move to the top of the step block 643. At this time, the electric push rod 75 is started, and the push plate 76 and the step pressure plate 77 are driven by the electric push rod 75 to move downward and abut against the step surface of the step block 643. The step pressure plate 77 with a porous structure can apply pressure to the insulating pad while making it fully contact with the mineral insulating oil, thereby simulating the situation of the insulating pad inside the transformer to the maximum extent, which is conducive to improving the subsequent test results. The pressure sensor 68 reading N2 is recorded at this time. The setting of the sealing plate 67, the first return frame 61, the second return frame 62 and the support plate 63 provides an installation space for the pressure sensor 68. At the same time, the thermal insulation film 69 plays a certain thermal insulation role to ensure the stability of the pressure sensor 68 during operation.

[0058] After a certain period of time, the push plate 76 and the stepped pressure plate 77 are first reset by the electric push rod 75, and then the drive motor 411 drives the drive shaft 412, the first wire wheel 413, the first traction line 414, the second wire wheel 415 and the second traction line 416 to rotate in the opposite direction. At this time, the first wire wheel 413 will drive the first traction line 414 to rewind and drive the cover plate 33 to reset under the action of the guide wheel 37. During the reset process, the cover plate 33 will drive the pressure component 7 to translate to On one side of the step block 643, the second wire wheel 415 will drive the second traction wire 416 to unwind. At this time, the gravity block 44 will drive the left side of the driving plate 43 to rotate downward. At the same time, its right end will drive the support assembly 6 to move upward and expose the insulating pads on the step surface of the step block 643. The tested insulating pads are manually taken out and their various performance indicators are tested and then compared with the standard indicators, so as to obtain the aging condition of the insulating pads during the heating time under the differential pressure of N2-N1.

[0059] In addition, the present invention also provides a method for testing an insulating spacer block using the above-mentioned oil-immersed transformer insulating spacer block accelerated thermal aging test device, comprising the following steps:

[0060] S1. First, the tester places the oil-immersed transformer insulation pad accelerated thermal aging test device flat on the ground, and then holds the handle 644 to drive the step block 643 and the threaded rod 642 to rotate. The threaded rod 642 can rotate upward or downward on the internal threaded cylinder 641, so as to adjust the step block 643 to the specified test height, and then place the insulation pad to be tested into the placement groove on the step block 643, and then add a proper amount of mineral insulating oil into the test box 5;

[0061] S2, start the drive motor 411, and drive the drive shaft 412, the first wire wheel 413, the first traction line 414, the second wire wheel 415 and the second traction line 416 to rotate. At this time, the second wire wheel 415 will drive the second traction line 416 to reel in, thereby driving the end of the drive plate 43 equipped with the gravity block 44 to rotate upward, and at the same time, the drive plate 43 rotates downward away from the end with the gravity block 44 and drives the L-shaped connecting rod 65 to move downward. Due to the setting of the rectangular slide groove and the extrusion spring 66, the L-shaped connecting rod 65 will also drive the support plate 63 and the loading unit 64 to move downward and immerse the insulating pad on the step surface of the step block 643 in the mineral insulating oil until the lower end of the support plate 63 contacts the upper end of the pressure sensor 68, and record the pressure sensor 68 at this time. Indication N1, when the carrier unit 64 and the insulating pad are immersed in the mineral insulating oil, the mineral insulating oil level will rise. At this time, the anti-overflow plate 31 can prevent the mineral insulating oil from overflowing, and the rubber strip 32 can play a certain limiting role in the rotation of the driving plate 43. When the driving plate 43 rotates downward to abut against the rubber strip 32, it means that it has been rotated to the maximum limit. The No. 1 wire wheel 413 will also drive the first traction line 414 to unwind during the rotation process. At this time, the cover plate 33 will rotate to the upper end of the test box 5 under the reaction of the torsion spring and make the test box 5 airtight. At this time, the heating rod 34 will also be immersed in the mineral insulating oil, and the mineral insulating oil around the insulating pad will be heated by the heating rod 34. At the same time, the heating time and heating temperature are recorded by the temperature monitor 35;

[0062] S3, in the process of the cover plate 33 rotating to the upper end of the test box 5, the linkage rope 73 will shrink, and the reaction force of the tension spring 72 will drive the slide plate 71, the cross bar 74, the electric push rod 75, the push plate 76 and the step pressure plate 77 to move to the top of the step block 643, at this time, the electric push rod 75 is started, and the push plate 76 and the step pressure plate 77 are driven by the electric push rod 75 to move downward and abut on the step surface of the step block 643, and the step pressure plate 77 with a porous structure can exert pressure on the insulating pad while making it fully contact with the mineral insulating oil, thereby simulating the situation of the insulating pad inside the transformer to the maximum extent, which is conducive to improving the subsequent test results, and recording the reading N2 of the pressure sensor 68 at this time, the setting of the sealing plate 67, the first return frame 61, the second return frame 62 and the support plate 63 provides an installation space for the pressure sensor 68, and the thermal insulation film 69 plays a certain thermal insulation role to ensure the stability of the pressure sensor 68 during operation;

[0063] S4: After 100 hours, the push plate 76 and the step pressure plate 77 are first reset by the electric push rod 75, and then the drive motor 411 drives the drive shaft 412, the first wire wheel 413, the first traction line 414, the second wire wheel 415 and the second traction line 416 to rotate in the opposite direction. At this time, the first wire wheel 413 drives the first traction line 414 to rewind and drives the cover plate 33 to reset under the action of the guide wheel 37. During the reset process, the cover plate 33 drives the pressure component 7 through the linkage rope 73. It moves horizontally to one side of the step block 643, and the second wire wheel 415 will drive the second traction wire 416 to unwind. At this time, the gravity block 44 will drive the left side of the driving plate 43 to rotate downward. At the same time, its right end will drive the support assembly 6 to move upward and expose the insulating pad on the step surface of the step block 643. The tested insulating pad is taken out manually and its various performance indicators are tested and then compared with the standard indicators, so as to obtain the aging condition of the insulating pad within 100 hours under the differential pressure of N2-N1.

[0064] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of the present invention is defined by the attached claims and their equivalents.

Claims

1. An accelerated thermal aging test device for insulating pads of oil-immersed transformers, comprising a base plate (1) and a support (2) fixed to the upper end of the base plate (1), characterized in that: The upper end of the support (2) is fixedly connected to an L-shaped box (3), a driving assembly (4) is arranged inside the L-shaped box (3), the end of the L-shaped box (3) away from the support (2) is open and fixedly connected to a test box (5), a support assembly (6) is fixedly installed at the bottom of the test box (5), the support assembly (6) and the driving assembly (4) are fixedly connected, and a pressure assembly (7) is arranged above the support assembly (6); The test box (5) has a rectangular through slot in the middle of the bottom; The support assembly (6) comprises: A first return frame (61), the upper end of the rectangular through groove is sealedly connected to the first return frame (61), and a return groove is provided inside the first return frame (61); A second return frame (62), the second return frame (62) being installed in a sliding and sealing manner inside the return groove; A support plate (63), the upper end of the second return frame (62) is sealedly connected to the support plate (63); A loading unit (64), the loading unit (64) being fixedly mounted at the middle portion of the upper end of the support plate (63); An L-shaped connecting rod (65), the side of the support plate (63) close to the L-shaped box (3) is provided with an L-shaped connecting rod (65), and a rectangular sliding groove is provided inside the end of the L-shaped connecting rod (65) facing the support plate (63); A squeezing spring (66), the end of the support plate (63) is slidably mounted in the rectangular slide groove, and a squeezing spring (66) is arranged between the side wall of the rectangular slide groove and the end of the support plate (63); A sealing plate (67) is fixedly mounted on the lower end of the rectangular through groove; A pressure sensor (68), wherein a pressure sensor (68) is fixedly disposed at the middle portion of the upper end of the sealing plate (67); A heat insulation film (69), wherein a heat insulation film (69) is provided on the sealing plate (67) outside the pressure sensor (68), and an upper end of the heat insulation film (69) is fixedly connected to a lower end surface of the support plate (63); An anti-overflow plate (31) is provided inside the end of the L-shaped box (3) away from the support (2), and a rubber strip (32) is fixedly installed in the middle of the upper end of the anti-overflow plate (31); The upper end surface of the end of the L-shaped box (3) away from the support (2) is rotatably connected to a cover plate (33) via a torsion spring, a plurality of heating rods (34) are arranged on the side wall of the cover plate (33) close to the test box (5), and a temperature monitor (35) is arranged on the side wall of the cover plate (33) away from the test box (5), and the temperature monitor (35) and the heating rods (34) are connected via electrical signals; The driving assembly (4) comprises a driving unit (41), wherein the driving unit (41) is arranged near the upper end of the L-shaped box (3), the lateral end of the driving unit (41) is fixedly connected to the cover plate (33), the vertical end of the driving unit (41) is connected to the driving plate (43), a rotating shaft (42) is fixedly installed near the middle of the driving plate (43), the end of the rotating shaft (42) is rotatably connected to the side wall of the L-shaped box (3), a gravity block (44) is fixedly installed at the lower end of the end of the driving plate (43) away from the rotating shaft (42), and the end of the driving plate (43) near the rotating shaft (42) extends into the test box (5) and is fixedly connected to an L-shaped connecting rod (65); The driving unit (41) comprises a driving motor (411), the driving motor (411) is fixedly mounted on the outer wall of the L-shaped box (3) near the upper end, the output shaft of the driving motor (411) is fixedly connected to the driving shaft (412), the end of the driving shaft (412) away from the driving motor (411) extends to the inside of the L-shaped box (3), a first wire wheel (413) is fixedly mounted in the middle of the driving shaft (412), a first traction line (414) is wound around the first wire wheel (413), the end of the first traction line (414) is fixedly bolted to the side wall of the cover plate (33), a second wire wheel (415) is symmetrically mounted on both sides of the first wire wheel (413), a second traction line (416) is wound around the second wire wheel (415), and the lower end of the second traction line (416) is fixedly bolted to the upper end of the driving plate (43); A through slot (36) is provided on the side wall of the L-shaped box body (3) facing the cover plate (33), and guide wheels (37) are symmetrically mounted in the through slot (36).

2. The accelerated thermal aging test device for insulating spacers of oil-immersed transformers according to claim 1 is characterized in that: The object-carrying unit (64) comprises an internally threaded barrel (641), the middle part of the upper end surface of the support plate (63) is fixedly connected to the internally threaded barrel (641), a threaded rod (642) is screwed to the inner side of the internally threaded barrel (641), a stepped block (643) is fixedly connected to the upper end of the threaded rod (642), a placement groove is provided on the stepped end surface of the stepped block (643), and a handle (644) is installed on the side wall of the stepped block (643).

3. The accelerated thermal aging test device for insulating spacers of oil-immersed transformers according to claim 2, characterized in that: The pressure-applying assembly (7) comprises a slide plate (71), a strip-shaped slide groove is provided at the upper end of the test box (5) near the edge, the slide plate (71) is slidably arranged in the strip-shaped slide groove, a cross bar (74) is symmetrically installed between opposite side walls of the slide plate (71), a tension spring (72) is installed between the side wall of the slide plate (71) away from the L-shaped box (3) and the inner wall of the test box (5), a linkage rope (73) is connected between the side wall of the slide plate (71) close to the L-shaped box (3) and the cover plate (33), an electric push rod (75) is fixedly installed on the lower end surface of the slide plate (71), a push plate (76) is fixedly connected to the lower end of the electric push rod (75), and a stepped pressure plate (77) is fixedly connected to the proximal end of the push plate (76).

4. The accelerated thermal aging test device for insulating spacers of oil-immersed transformers according to claim 3 is characterized in that: The stepped pressing plate (77) has a porous structure.

5. A method for testing using the accelerated thermal aging test device for oil-immersed transformer insulation pads according to claim 4, characterized in that: The method comprises the following steps: S1, the tester first holds the handle (644) to drive the step block (643) to rotate to the test height, then places the insulating pad to be tested into the placement groove on the step block (643), and then adds a proper amount of mineral insulating oil into the test box (5); S2, start the driving component (4), drive the supporting component (6) to move downward through the driving component (4) and make the lower end of the step block (643) contact the upper end of the pressure sensor (68), record the reading N1 of the pressure sensor (68), at this time, the insulating pad in the groove on the step block (643) is immersed in the mineral insulating oil, and the cover plate (33) will cover the upper end of the test box (5) to make the test box (5) airtight, and at the same time, the pressure component (7) moves to the top of the step block (643); S3, applying pressure to the insulating pad in the placement groove through the pressure applying component (7), recording the reading N2 of the pressure sensor (68), and then heating the mineral insulating oil around the insulating pad through the heating rod (34), and recording the heating time and heating temperature through the temperature monitor (35); S4: After 100 hours, the pressure-applying assembly (7) and the driving assembly (4) are reset, and the insulating spacer to be tested is manually taken out and its various performance indicators are tested and then compared with the standard indicators, thereby obtaining the aging condition of the insulating spacer within 100 hours under the N2-N1 pressure.

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