An oil-paper insulation experimental device with insulating oil dynamic compensation function and a vacuum oil filling method

Abstract

The present invention discloses an oil-paper insulation experimental device and vacuum oil filling method with a dynamic compensation function for insulating oil. The device comprises an experimental chamber, a vacuum oil filling device, and a lifting balance device. The experimental chamber comprises an experimental chamber body, a spherical electrode installed at the center of the top of the experimental chamber body via a first electrode column, and a plate electrode installed at the center of the bottom of the experimental chamber body via a second electrode column and symmetrically arranged with the spherical electrode. The insulating paper is placed on the plate electrode. The vacuum oil filling device comprises an oil replenishing bottle, a vacuum pump, a water removal unit, and a gas collecting bottle. The lifting device comprises a support rod connected to the bottom of the experimental chamber body and an adjustment mechanism for adjusting the lifting of the support rod. The present invention can ensure the effective removal of impurities such as microbubbles, microwater, and microoxygen inside the chamber during oil filling before the experiment, and can automatically remove bubbles generated during the experiment. At the same time, the present invention can conduct experiments without being restricted by terrain and can collect and analyze the gases generated during the experiment.

Description

Technical Field

[0001] The present invention belongs to the technical field of high voltage electricity, and specifically relates to a simulated oil-paper insulation test device, and more particularly to an oil-paper insulation test device with a dynamic compensation function for insulating oil and a vacuum oil filling method. Background Art

[0002] The valve side of converter transformers primarily utilizes oil-paper insulation. Before commissioning, the water content of the insulating oil should be less than 10 ppm, and the moisture content of the insulating paper less than 0.5%. However, after 25 years of operation, the moisture content of the insulating paper within a converter transformer can reach approximately 5%. Due to the conductivity of moisture, this increases the leakage current flowing through the oil-paper insulation, leading to increased heat generation and the evaporation of moisture, which in turn forms bubbles. Furthermore, factors such as internal load fluctuations, DC bias, high-order harmonics, and ambient temperature fluctuations, combined with the unique structural characteristics of converter transformers, lead to uneven temperature distribution, easily forming localized hot spots and accelerating moisture evaporation. Furthermore, when partial discharge occurs in the oil, the insulating oil decomposes to produce gases such as methanol and hydrogen. These gases expand under the influence of buoyancy and the electric field, forming small gas bridges connecting the two electrodes, ultimately leading to insulation failure. Therefore, simulating the aging of oil-paper insulation to determine the water and gas content under different aging conditions is crucial for diagnosing and repairing converter transformer insulation faults.

[0003] The existing simulated oil-paper insulation aging test device mainly has the following oil filling methods: (1) directly using a motor to transport the insulating oil into the cavity, which may not only generate bubbles, but also contact with air throughout the process, which increases the water content of the insulating oil; (2) using a vacuum pump to vacuum the oil. When the oil is about to reach the top of the cavity, the air gap is extremely small, and the pressure difference generated is very small, which is not enough to suck the insulating oil into the cavity, resulting in bubbles in the cavity. Moreover, the above two situations do not take into account the thermal expansion and contraction of the insulating oil during the experiment. In addition, the existing simulated oil-paper insulation aging test device cannot exhaust the gas generated during the experiment. Summary of the Invention

[0004] The purpose of the present invention is to address the problems of bubbles and water intrusion in the cavity of the current experimental device, and to design an oil-paper insulation experimental device with a dynamic compensation function for insulating oil, so as to remove impurities such as micro bubbles and micro water inside the cavity and ensure the credibility of the experiment.

[0005] Another object of the present invention is to provide a vacuum oil filling method suitable for the above-mentioned oil-paper insulation experimental device.

[0006] In order to achieve the above objectives, the present invention adopts the following technical solutions.

[0007] The oil-paper insulation experimental device provided by the present invention has the function of dynamic compensation of insulating oil, which includes an experimental chamber, a vacuum oil filling device and a lifting balance device;

[0008] The experimental chamber includes an experimental chamber body, a spherical electrode installed at the center of the top of the experimental chamber body via a first electrode column, and a plate electrode installed at the center of the bottom of the experimental chamber body via a second electrode column and symmetrically arranged with the spherical electrode, with insulating paper placed on the plate electrode; an oil filling port is also provided on one side of the experimental chamber body, and a valve a is installed on the pipe connected to the oil filling port; a spirit level perpendicular to the second electrode column is provided on the outside of the experimental chamber body; the second electrode column passes through the bottom of the experimental chamber body, and the depth of the second electrode column into the experimental chamber body is adjusted by a micrometer abutting against it; a pressure gauge is also provided on the top of the experimental chamber body; a valve b is installed at the connection between the pressure gauge and the experimental chamber body;

[0009] The vacuum oil filling device includes an oil replenishment bottle, a vacuum pump, a water removal unit, and a gas collecting bottle. The top of the oil replenishment bottle is connected to the vacuum pump or the water removal unit through a three-way pipe via valves c and d respectively; the bottom of the oil replenishment bottle is connected to the top of the experimental chamber body through valve e; the gas collecting bottle is located behind the water removal unit, and its inlet is connected to the outlet of the water removal unit through a pipe.

[0010] The lifting device includes a support rod connected to the bottom of the experimental chamber body and an adjustment mechanism for adjusting the lifting of the support rod.

[0011] In the above-mentioned oil-paper insulation experimental device with the insulating oil dynamic compensation function, a sealing flange is installed at the position where the oil filling port of the experimental cavity body is connected to the pipeline.

[0012] In the above-mentioned oil-paper insulation experimental device with the function of dynamic compensation of insulating oil, the experimental chamber body is formed by a groove and a top cover which are fixedly connected, and a sealing ring is provided at the connection position between the groove and the top cover.

[0013] In the above-mentioned oil-paper insulation experimental device with the insulating oil dynamic compensation function, the first electrode column passes through the top of the experimental cavity body and is connected to the voltage-equalizing ball.

[0014] In the above-mentioned oil-paper insulation experimental device with the dynamic compensation function of insulating oil, the second electrode column is movably connected to the bottom of the experimental chamber body through a fixing piece; the micrometer is embedded in the fixing piece and abuts against the second electrode column.

[0015] The oil-paper insulation experimental device with the insulating oil dynamic compensation function is characterized in that the dehydration unit includes a transparent container and an aqueous desiccant placed in the transparent container. A flow meter is also provided at the inlet end of the dehydration unit.

[0016] In the oil-paper insulation test device with dynamic insulation oil compensation, the adjustment mechanism includes a screw and a bevel gear meshing therewith. The support rod is hollow and has internal threads that mate with the screw. A non-slip base is also provided at the bottom of the support rod.

[0017] The present invention further provides a vacuum oil filling method applicable to the above oil-paper insulation experimental device, comprising the following steps:

[0018] S1 places insulating paper on the plate electrode, then seals the experimental chamber and connects valve c to the vacuum pump;

[0019] S2 adjusts the experimental chamber body through the lifting device so that the bubble in the level moves toward the oil replenishing bottle until it cannot move;

[0020] S3 closes valve a, opens valves b, c, d, and e, and evacuates the experimental chamber until the vacuum degree meets the requirements;

[0021] S4 closes valve c, opens valve a, and injects insulating oil into the experimental chamber to a height of 3-5 cm from the top of the experimental chamber body;

[0022] S5 closes valve a, opens valve c, and evacuates the oil supply bottle until the vacuum degree meets the requirements;

[0023] S6 Close valves b and c, open valve a, and continue to inject insulating oil until it reaches 0.5-2 cm from the top of the oil replenishment bottle;

[0024] S7: Close valve a, valve b, and valve c, open valve d, and connect the oil replenishing bottle to the water removal unit.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] (1) The present invention can ensure the effective removal of impurities such as microbubbles, microwater, and microoxygen inside the cavity when filling oil before the experiment, and can automatically remove the gas generated during the experiment;

[0027] (2) The lifting device used in the present invention is not restricted by terrain, and experiments can be carried out even on uneven ground;

[0028] (3) The gas collection device used in the present invention can realize gas analysis of the gases generated at different stages during the experiment, thereby determining the aging condition of the experimental materials;

[0029] (4) The entire device has a simple structure, ingenious design, low cost, and does not require manpower, ensuring the safety of experimenters in high voltage environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1This is a structural diagram of the oil-paper insulation experimental device with dynamic compensation function of insulating oil.

[0031] In the figure, 1-experimental chamber, 11-experimental chamber body, 12-first electrode column, 13-ball electrode, 14-second electrode column, 15-plate electrode, 16-insulating paper, 17-oil filling port, 18-level, 19-micrometer, 110-fixing part, 111-pressure gauge, 112-pressure equalizing ball, 113-flange, 114-groove, 115-top cover, 116-sealing ring, 117-fastener; 2-vacuum oil filling device, 21-oil replenishing bottle, 22-vacuum pump, 23-water removal unit, 24-gas collecting bottle, 25-flow meter, 3-lifting balancing device; 31-support rod; 32-adjusting mechanism, 321-screw, 322-bevel gear, 323-anti-slip base. DETAILED DESCRIPTION

[0032] The principles and features of the present invention are described below. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0033] Example 1

[0034] like Figure 1 As shown, this embodiment provides an oil-paper insulation experimental device with a dynamic compensation function of insulating oil, which includes an experimental chamber 1, a vacuum oil injection device 2 and a lifting balance device 3.

[0035] like Figure 1As shown, the experimental chamber 1 includes an experimental chamber body 11, a spherical electrode 13 and a plate electrode 15. The experimental chamber body 11 is composed of a groove 114 and a top cover 115, which are fixedly connected. The connection position between the groove and the top cover is provided with a sealing ring 116; the groove 114 and the top cover 115 are fixedly connected by 16 nuts evenly distributed along the circumference thereof to achieve sealing of the groove. The spherical electrode 13 is installed at the top center position of the experimental chamber body through the first electrode column 12. The first electrode column 12 passes through the top of the experimental chamber body 11 and is connected to the equalizing ball 112 to reduce the influence of corona on the experimental results; a gasket and a nut are also provided between the equalizing ball 112 and the top of the experimental chamber body. The plate electrode is disc-shaped and is used to place the insulating paper 16; the plate electrode 15 is installed at the bottom center position of the experimental chamber body through the second electrode column 14 and is symmetrically arranged with the spherical electrode. The second electrode column 14 is movably connected to the bottom of the experimental chamber body 11 via a fixture 117. The fixture is a cylindrical structure with closed ends, and its end surfaces each feature a second electrode column mounting hole and a micrometer mounting hole. One end of the fixture is fixedly connected to the bottom of the experimental chamber body, and the other end is threadedly connected to a micrometer embedded within it. The second electrode column 14, located within the fixture cavity, is secured by a fastener 117 and abuts against a micrometer 19. By rotating the micrometer, the height of the second electrode column within the experimental chamber body can be adjusted, thereby achieving high-precision adjustment of the distance between the plate electrode and the ball electrode. An oil filling port 17 is also provided on one side of the experimental chamber body 11. A valve a is installed on the pipe connecting the oil filling port. A sealing flange 113 is installed at the connection between the oil filling port 17 and the pipe, and the sealing flange is secured to the oil outlet of the experimental chamber body via a nut. A level 18 is provided on the outside of the experimental chamber body 11, perpendicular to the second electrode column 14. A pressure gauge 111 is also provided on the top of the experimental chamber body 11; the bottom of the pressure gauge has an internal thread that matches the internal and external thread joints, and the valve b has an external thread that matches the internal and external thread joints, so that the bottom of the pressure gauge is connected to the valve b via the internal and external thread joints; the other end of the valve b is connected to the pipeline that directly extends into the experimental chamber body 11.

[0036] The vacuum oil filling device 2 includes an oil replenishment bottle 21, a vacuum pump 22, a dewatering unit 23, and a gas collection bottle 24. The top of the oil replenishment bottle 21 is connected to the vacuum pump 22 and the dewatering unit 22 via a three-way pipe. The pipes connecting the vacuum pump and the dewatering unit are respectively provided with valves c and d. The oil replenishment bottle 21 is located above a corner on the left side of the top of the experimental chamber body. The bottom of the oil replenishment bottle 21 has internal threads that match the internal and external thread connectors, and valve e has external threads that match the internal and external thread connectors, connecting the bottom of the oil replenishment bottle 21 to valve e via the internal and external thread connectors. The other end of valve e is connected to a pipe that extends directly into the experimental chamber body 11. The dewatering unit 23 includes a transparent container and an aqueous desiccant placed within the transparent container. In this embodiment, the transparent container is a glass bottle, and the aqueous desiccant is anhydrous copper sulfate granules. The gas collection bottle 24 is located behind the dewatering unit, and its inlet is connected to the outlet of the dewatering unit via a pipe. A flowmeter 25 is also provided at the inlet of the dewatering unit 23 to measure the amount of gas collected by the gas collection bottle.

[0037] The lifting device 3 includes a support rod 31 connected to the bottom of the experimental chamber body 11 and an adjustment mechanism 32 for adjusting the lifting of the support rod 31. This embodiment uses four support rods 31 and an adjustment mechanism 32 matching them. The four support rods are divided into two groups and are symmetrically installed at the bottom of the experimental chamber body. The adjustment mechanism 32 includes a screw 321 and a bevel gear 322 meshing with it; the interior of the support rod 31 is a hollow structure, and the inner side is designed with an internal thread that cooperates with the screw. A non-slip base 323 is also provided at the bottom of the support rod. A handle is provided at the free end of the bevel gear for easy operation. By rotating the handle, the length of the screw penetrating into the support rod can be adjusted, thereby achieving height adjustment of the experimental chamber body.

[0038] This embodiment further provides a vacuum oil filling method applicable to the above-mentioned oil-paper insulation experimental device, comprising the following steps:

[0039] S1 places insulating paper on the plate electrode, then seals the experimental chamber and connects valve c to the vacuum pump.

[0040] S2 adjusts the experimental chamber body through the lifting device so that the bubble in the spirit level moves toward the oil replenishing bottle until it cannot move. Specifically, by rotating the bevel gear of the support rod on the side of the oil replenishing bottle, the support rod is raised, and the position of the bubble in the spirit level is observed at the same time. When the bubble in the spirit level moves toward the oil replenishing bottle until it cannot move, the adjustment is stopped.

[0041] S3 closes valve a, opens valves b, c, d, and e, and evacuates the experimental chamber to meet the requirements; specifically: before evacuating the chamber, check the power cord of the vacuum pump to ensure that the test device is well grounded, and test the vacuum pump to check the vacuum degree; connect the vacuum pump to the oil replenishing bottle, and check whether the connection is intact and there is no air leakage, then start evacuating the experimental chamber, observe the pressure display, evacuate to the specified vacuum degree below 1kPa and maintain the vacuum degree for 20 minutes, and check whether the chamber is sealed tightly.

[0042] S4 closes valve c, opens valve a, and starts injecting insulating oil into the experimental chamber through the oil pump until it reaches 3-5 cm from the top of the experimental chamber body.

[0043] S5 closes valve a, opens valve c, stops oil filling, and maintains this for 5 minutes; since the oil supply bottle is at the highest position, the other three corners have been filled with insulating oil, leaving only the oil supply bottle with a gap; at this time, continue to evacuate the oil supply bottle with a vacuum pump to a vacuum degree below 1 kPa.

[0044] S6: Close valves b and c, open valve a, and continue to inject insulating oil into the oil replenishment bottle until it reaches 0.5-2 cm from the top. Stop injecting oil. Closing valve b prevents insulating oil from entering the pressure gauge.

[0045] S7: Close valve a, valve b, and valve c, open valve d, and connect the oil replenishing bottle to the water removal unit.

[0046] Before vacuum oil filling, the present invention first inserts insulating paper, then adjusts the lifting and balancing device so that the bubbles in the spirit level move toward the oil replenishment bottle until they cannot move. The experimental chamber is then evacuated to a specified vacuum level. Insulating oil is then injected into the chamber until it reaches near the top of the oil replenishment bottle, and a dewatering unit is used to remove any traces of water within the chamber. These operations remove all impurities, such as microbubbles, traces of water, and traces of oxygen, from the chamber. Anhydrous copper sulfate particles ensure that the insulating oil in the oil replenishment bottle is kept out of contact with air. During the oil-paper insulation experiment, gas generation and temperature fluctuations may cause air gaps within the chamber. However, because valve e is open and the oil replenishment bottle is relatively high, bubbles will be concentrated below the oil replenishment bottle and then flow through valve e into the bottle. The insulating oil in the bottle will then enter the chamber, maintaining a microbubble-free interior. The liquid within the chamber is never exposed to the outside air, enhancing the reliability of the experiment. This process is entirely human-free, ensuring the safety of the experimenters. If the generated gas needs to be analyzed during the experiment, it can be collected through a flow meter and a negative pressure gas collection bottle. The gas analysis function can provide auxiliary feedback on the experimental situation and then adjust the experimental steps.

[0047] Although the embodiments of the present invention have been shown and described above, it will be understood that the above embodiments are illustrative and are not to be construed as limitations on the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

Claims

1. An oil-paper insulation experimental device with a dynamic compensation function of insulating oil, characterized in that: It includes an experimental chamber (1), a vacuum oil injection device (2) and a lifting and balancing device (3); The experimental chamber (1) comprises an experimental chamber body (11), a spherical electrode (13) installed at the center of the top of the experimental chamber body via a first electrode column (12), and a plate electrode (15) installed at the center of the bottom of the experimental chamber body via a second electrode column (14) and symmetrically arranged with the spherical electrode, and an insulating paper (16) is placed on the plate electrode (15); an oil filling port (17) is further provided on one side of the experimental chamber body (11), and a valve a is installed on the pipe connected to the oil filling port; a level (18) perpendicular to the second electrode column (14) is provided on the outside of the experimental chamber body (11); the second electrode column (14) passes through the bottom of the experimental chamber body, and the height of the second electrode column penetrating into the experimental chamber body is adjusted by a micrometer (19) abutting against it; a pressure gauge (111) is further provided on the top of the experimental chamber body (11); a valve b is installed at the connection position between the pressure gauge and the experimental chamber body; The vacuum oil filling device (2) comprises an oil replenishing bottle (21), a vacuum pump (22), a water removal unit (23) and a gas collecting bottle (24); the top of the oil replenishing bottle (21) is connected to the vacuum pump (22) or the water removal unit (23) through a three-way pipe via valve c and valve d respectively; the bottom of the oil replenishing bottle (21) is connected to the top of the experimental chamber body (11) through valve e; the gas collecting bottle (24) is located behind the water removal unit, and its inlet is connected to the outlet of the water removal unit through a pipe; The lifting balance device (3) comprises a support rod (31) connected to the bottom of the experimental chamber body (11) and an adjustment mechanism (32) for adjusting the lifting of the support rod (31).

2. The oil-paper insulation experimental device with insulating oil dynamic compensation function according to claim 1 is characterized in that: A sealing flange (113) is installed at the location where the oil filling port (17) of the experimental chamber body is connected to the pipeline.

3. The oil-paper insulation experimental device with insulating oil dynamic compensation function according to claim 1 or 2, characterized in that: The experimental chamber body (11) is formed by a groove (114) and a top cover (115) being fixedly connected to each other, and a sealing ring (116) is provided at the connection position between the groove and the top cover.

4. The oil-paper insulation experimental device with insulating oil dynamic compensation function according to claim 1 is characterized in that: The first electrode column (12) passes through the top of the experimental chamber body (11) and is connected to the pressure equalizing ball (117).

5. The oil-paper insulation experimental device with insulating oil dynamic compensation function according to claim 1 is characterized in that: The second electrode column (14) is movably connected to the bottom of the experimental chamber body (11) via a fixing member (110); the micrometer (19) is embedded in the fixing member (110) and abuts against the second electrode column (14).

6. The oil-paper insulation experimental device with insulating oil dynamic compensation function according to claim 1 is characterized in that: The dehydration unit (23) comprises a transparent container and an aqueous desiccant placed in the transparent container.

7. The oil-paper insulation experimental device with insulating oil dynamic compensation function according to claim 6 is characterized in that: The inlet end of the initial unit is also provided with a flow meter.

8. The oil-paper insulation experimental device with insulating oil dynamic compensation function according to claim 1 is characterized in that: The adjusting mechanism (32) includes a screw (321) and a bevel gear (322) meshing therewith; the interior of the support rod (31) is a hollow structure, and an internal thread is designed on the inside thereof to cooperate with the screw; and an anti-slip base (323) is also provided at the bottom of the support rod.

9. A vacuum oil filling method applicable to the oil-paper insulation experimental device according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1 Place insulating paper on the plate electrode, then seal the experimental chamber and connect valve c to the vacuum pump; S2 adjusts the experimental chamber body through the lifting balance device so that the bubble in the spirit level moves toward the oil replenishing bottle until it cannot move; S3 Close valve a, open valves b, c, d, and e, and evacuate the experimental chamber until the vacuum degree meets the requirements; S4 Close valve c, open valve a, and inject insulating oil into the experimental chamber to a height of 3-5 cm from the top of the experimental chamber body; S5 Close valve a, open valve c, and evacuate the oil supply bottle until the vacuum degree meets the requirements; S6 Close valves b and c, open valve a, and continue to inject insulating oil until it reaches 0.5-2 cm from the top of the oil replenishment bottle; S7 Close valves a, b, and c, open valve d, and connect the oil replenishment bottle to the water removal unit.

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