A test tool for voltage breakdown strength of insulating materials

Abstract

This utility model relates to a voltage breakdown strength testing fixture for insulating materials, comprising an insulating container, a fixed metal electrode, and a movable metal electrode, the fixed and movable metal electrodes being coaxial. Two opposing slots are formed on the inner wall of the insulating container, with the plane of the two slots located between the fixed and movable metal electrodes. The test sample placed in the slot is positioned between the fixed and movable metal electrodes and is in contact with both electrodes. When the bottom of the slot supports the test sample, the axis of the movable metal electrode passes through the center of the test sample. This utility model provides space for the test sample through the slots, and by utilizing the relative positional relationship between the slots and the movable and fixed metal electrodes, it ensures that after the test sample is placed in the slot, the axes of the movable and fixed metal electrodes pass through the center of the test sample, thereby ensuring stable and reliable testing.

Description

Technical Field

[0001] This utility model relates to the field of voltage breakdown testing technology, and in particular to a tooling for voltage breakdown testing, specifically a tooling for testing the voltage breakdown strength of insulating materials. Background Technology

[0002] High-voltage switchgear is one of the most technically demanding and difficult-to-manufacture pieces of equipment in high-voltage power transmission projects. Epoxy-cast insulators are crucial components of high-voltage switchgear, and their performance directly determines the insulation performance and operational reliability of the switchgear.

[0003] The breakdown field strength performance of epoxy cast insulators is particularly important. With the increasing demands for reliability in power system operation, higher requirements are being placed on the breakdown field strength performance of insulators. Breakdown field strength is one of the important parameters of vacuum-cast epoxy resin insulating materials. The breakdown field strength referred to here is the electric field strength that the insulating material withstands when it breaks down. Breakdown field strength is an important parameter for evaluating the insulation performance of thermosetting cast materials such as epoxy insulating adhesives. It is the ratio between the voltage at which the test sample breaks down and the thickness of the test sample between the positive and negative electrodes.

[0004] Currently, common breakdown field strength testing devices have the problem of inconvenient operation. After the test sample is placed, it is not easy to align the electrodes with the center of the test sample. Moreover, when testing test samples of different thicknesses, the device needs to be readjusted each time, which is not conducive to improving testing efficiency. Utility Model Content

[0005] This invention addresses the shortcomings of existing technologies by providing a voltage breakdown strength testing fixture for insulating materials, which facilitates the alignment of the electrodes with the center of the test sample.

[0006] This utility model is achieved through the following technical solution: a voltage breakdown strength testing fixture for insulating materials is provided, including an insulating tank, a fixed metal electrode fixed inside the insulating tank, and a movable metal electrode slidably disposed on the insulating tank. The fixed metal electrode and the movable metal electrode are coaxial. Two opposing slots are formed on the inner wall of the insulating tank. The plane of the two slots is located between the fixed metal electrode and the movable metal electrode. The test sample placed in the slot is located between the fixed metal electrode and the movable metal electrode and is in contact with the fixed metal electrode and the movable metal electrode respectively. When the bottom of the slot supports the test sample, the axis of the movable metal electrode passes through the center of the test sample.

[0007] This application provides space for the test sample by setting a slot, and supports the test sample by using the bottom of the slot. By utilizing the relative positional relationship between the bottom of the slot and the movable and fixed metal electrodes, the center of the test sample is aligned with the movable and fixed metal electrodes after placement. The sliding movable metal electrode facilitates the placement and clamping of the test sample, ensuring good contact.

[0008] As an optimization, a fixed shaft is provided through the side wall of the insulating tank. A first limiting platform is fixed to one end of the fixed shaft extending into the insulating tank, and a positioning nut is threadedly connected to the other end of the fixed shaft extending outside the insulating tank. The end of the fixed metal electrode furthest from the movable metal electrode extends into the fixed shaft and is threadedly connected to it. In this optimized solution, the fixed metal electrode is fixed to the insulating tank by the fixed shaft, and the fixed shaft is fixed to the insulating tank by the positioning nut and the first limiting platform. The structure is simple and easy to assemble and disassemble.

[0009] As an optimization, a fixing sleeve is provided on the side wall of the insulating tank. A second limiting platform is fixed to one end of the fixing sleeve extending into the insulating tank, and an outer sleeve is fitted to the other end of the fixing sleeve extending out of the insulating tank. The outer sleeve and the fixing sleeve are connected by threads, and a sealing plate is fixed to the end of the outer sleeve away from the movable metal electrode. The movable metal electrode is in sealed sliding contact with the inner wall of the fixing sleeve. A pull rod passing through the sealing plate is fixed to the movable metal electrode, and a spring is fitted on the pull rod. One end of the spring abuts against the movable metal electrode, and the other end abuts against the sealing plate. This optimized solution uses the outer sleeve and the second limiting platform to fix the fixing sleeve to the insulating tank. The inner hole of the fixing sleeve provides sliding support and guidance for the movable metal electrode. The spring allows the movable metal electrode to be moved away from the fixed metal electrode when the test sample is placed. After the test sample is placed, the spring force makes the movable metal electrode press against the test sample, ensuring reliable contact.

[0010] As an optimization, the outer surface of the movable metal electrode is provided with at least two sealing grooves arranged along its axial direction, and sealing rings are disposed in the sealing grooves. This optimization scheme improves the sealing performance between the movable metal electrode and the fixed sleeve by providing at least two sealing rings, thus preventing oil leakage from the insulating tank.

[0011] As an optimization, the insulating can is a cylindrical shape with an open top, and the two slots are opposite each other along the diameter of the inner cavity of the insulating can, extending upwards to the upper surface of the insulating can. This optimized design, with the slots open at the top, makes it easier to load test samples.

[0012] As an optimization, the test sample is circular. The bottom edge of the slot, near the inner cavity of the insulating container, forms a support point for the test sample. The distances between the support points of the two slots and the axis of the fixed metal electrode are equal, and both are equal to the radius of the test sample. This optimized design is more suitable for common circular test samples. By setting the distances between the support points of the two slots and the axis of the fixed metal electrode, the center of the test sample is ensured to be aligned with the two electrodes.

[0013] Preferably, the width of the slot is 4-5 mm. This optimized slot width setting can accommodate test samples of various common thicknesses, expanding the applicability of this fixture.

[0014] The beneficial effects of this utility model are as follows: by providing a space for the test sample through the set slot, and by ensuring the relative positional relationship between the slot and the movable metal electrode and the fixed metal electrode, it is ensured that after the test sample is placed in the slot, the axes of the movable metal electrode and the fixed metal electrode pass through the center of the test sample, thereby ensuring the stability and reliability of the test. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram of the test sample for the card slot support. As shown in the figure: 1. Pull rod, 2. Fixing sleeve, 3. Second limiting stage, 4. Movable metal electrode, 5. Slot, 6. First limiting stage, 7. Insulating tank, 8. Positioning nut, 9. Fixing shaft, 10. Fixing metal electrode, 11. Test sample, 12. Outer sleeve, 13. Spring. Detailed Implementation

[0016] To clearly illustrate the technical features of this solution, the following detailed implementation method will be used to explain the solution.

[0017] like Figure 1 The illustrated fixture for testing the voltage breakdown strength of insulating materials includes an insulating tank 7, a fixed metal electrode 10 fixed inside the insulating tank, and a movable metal electrode 4 slidably disposed on the insulating tank. The fixed metal electrode 10 and the movable metal electrode 4 are coaxial, and their axes are both horizontally aligned. In this embodiment, the insulating tank is a tetrafluoroethylene (PTFE) oil tank filled with insulating oil. Utilizing the excellent insulating properties of the PTFE oil tank, this fixture is suitable for various testing environments.

[0018] In this embodiment, the test sample 11 is circular and made of the insulating material to be tested. The insulating container is a cylindrical shape with an open top. Two opposing slots 5 are formed on the inner wall of the insulating container. The two slots are opposite each other along the diameter of the inner cavity of the insulating container and extend upwards to the upper surface of the insulating container. The bottom of the slots supports the test sample. The test sample 11, placed in the slot, is located between the fixed metal electrode 10 and the movable metal electrode 4, and is in contact with both the fixed and movable metal electrodes. When the test sample is not placed, the distance between the fixed and movable metal electrodes is no greater than the thickness of the test sample, and the ends of the fixed and movable metal electrodes that are close to each other are within the width of the slot, ensuring reliable contact between the test sample and the fixed and movable metal electrodes after the test sample is placed.

[0019] When the bottom of the slot supports the test sample, the axis of the movable metal electrode passes through the center of the test sample. In this embodiment, the bottom edge of the slot near the inner cavity of the insulating can forms a support point for the test sample. The distances between the support points of the two slots and the axis of the fixed metal electrode are equal, and both are equal to the radius of the test sample, so that any circular test sample that meets the radius requirement can be used.

[0020] The slot width of this embodiment is 4~5mm, preferably 4mm, which is suitable for voltage breakdown field strength testing of sheet-shaped test samples with a thickness of less than 4mm, thus expanding the applicability of this embodiment.

[0021] A fixed shaft 9 is installed on the side wall of the insulating tank. A first limiting platform 6 is fixed to one end of the fixed shaft 9 extending into the insulating tank. A positioning nut 8 is threadedly connected to the other end of the fixed shaft extending outside the insulating tank. The end of the fixed metal electrode, away from the movable metal electrode, extends into the fixed shaft and is threadedly connected to it. In this embodiment, the first limiting platform is circumferentially closed, and its outer diameter is larger than the diameter of the through hole in the side wall of the insulating tank through which the fixed shaft passes. When the positioning nut is tightened, the positioning nut and the first limiting platform clamp the side wall of the insulating tank, thus fixing the fixed shaft.

[0022] A fixing sleeve 2 is installed on the side wall of the insulating tank. A second limiting platform 3 is fixed to one end of the fixing sleeve 2 extending into the insulating tank. An outer sleeve 12 is fitted to the other end of the fixing sleeve extending out of the insulating tank. The outer sleeve 12 is threadedly connected to the fixing sleeve 2. A sealing plate is fixed to the end of the outer sleeve away from the movable metal electrode. The second limiting platform is circumferentially closed, and its outer diameter is larger than the diameter of the through hole in the side wall of the insulating tank through which the fixing sleeve passes. When the outer sleeve is turned, the outer sleeve and the second limiting platform clamp the side wall of the insulating tank, thus fixing the fixing shaft. The fixing shaft and the fixing sleeve are coaxial and both are arranged radially along the insulating tank.

[0023] The movable metal electrode 4 is slidably sealed to the inner wall of the fixed sleeve. A pull rod 1, which passes through the sealing plate along its axis, is fixed to the movable metal electrode. A spring 13 is sleeved on the pull rod, with one end of the spring 13 pressing against the movable metal electrode and the other end pressing against the sealing plate. The spring force allows for more stable and easier fixation of the test sample.

[0024] To improve the sealing effect and prevent oil inside the insulating tank from flowing out between the movable metal electrode and the fixed sleeve, at least two sealing grooves are provided on the outer surface of the movable metal electrode along its axial direction, and sealing rings are installed in the sealing grooves. In this embodiment, two sealing rings are used to ensure the sealing effect while also ensuring the flexibility of the movable metal electrode's movement.

[0025] In use, connect the positive and negative terminals of the power supply to the fixed metal electrode and the movable metal electrode, respectively. Pull the lever 1 to move the movable metal electrode away from the fixed metal electrode, creating space for the test sample. Then, insert the test sample into the slot from top to bottom. Release the pull on the lever, allowing the movable metal electrode to press the test sample against the fixed metal electrode under the action of the spring, ensuring reliable contact. Next, increase the voltage as required until the test sample breaks down, and record the breakdown voltage. Finally, calculate the breakdown strength performance of the test sample using the electric field strength calculation formula, thereby quantitatively characterizing the breakdown field strength performance of the insulating material of the test sample.

[0026] Of course, the above description is not limited to the examples above. Technical features of this utility model not described can be implemented by or using existing technology, and will not be repeated here. The above embodiments and drawings are only used to illustrate the technical solution of this utility model and are not intended to limit this utility model. This utility model has been described in detail with reference to preferred embodiments. Those skilled in the art should understand that any changes, modifications, additions or substitutions made by those skilled in the art within the scope of this utility model do not depart from the spirit of this utility model and should also fall within the protection scope of the claims of this utility model.

Claims

1. A fixture for testing the voltage breakdown strength of insulating materials, characterized in that: It includes an insulating tank (7), a fixed metal electrode (10) fixed inside the insulating tank, and a movable metal electrode (4) slidably disposed on the insulating tank, wherein the fixed metal electrode (10) and the movable metal electrode (4) are coaxial; The inner wall of the insulating tank is provided with two opposing slots (5). The test sample (11) placed in the slot is located between the fixed metal electrode (10) and the movable metal electrode (4), and is in contact with the fixed metal electrode and the movable metal electrode respectively. When the bottom of the slot supports the test sample, the axis of the movable metal electrode passes through the center of the test sample.

2. The voltage breakdown strength testing fixture for insulating materials according to claim 1, characterized in that: A fixed shaft (9) is provided on the side wall of the insulating tank. A first limiting platform (6) is fixed at one end of the fixed shaft (9) extending into the insulating tank. A positioning nut (8) is threadedly connected to one end of the fixed shaft extending out of the insulating tank. The end of the fixed metal electrode away from the movable metal electrode extends into the fixed shaft and is threadedly connected to the fixed shaft.

3. The voltage breakdown strength testing fixture for insulating materials according to claim 1, characterized in that: A fixing sleeve (2) is provided on the side wall of the insulating tank. A second limiting platform (3) is fixed at one end of the fixing sleeve (2) extending into the insulating tank. An outer sleeve (12) is fitted at one end of the fixing sleeve extending into the insulating tank. The outer sleeve (12) and the fixing sleeve (2) are connected by threads. A sealing plate is fixed at one end of the outer sleeve away from the movable metal electrode. The movable metal electrode (4) is slidably sealed to the inner hole wall of the fixed sleeve. A pull rod (1) passing through the sealing plate is fixed to the movable metal electrode. A spring (13) is sleeved on the pull rod. One end of the spring (13) pushes against the movable metal electrode, and the other end pushes against the sealing plate.

4. The voltage breakdown strength testing fixture for insulating materials according to claim 3, characterized in that: The outer surface of the movable metal electrode is provided with at least two sealing grooves arranged along its axial direction, and a sealing ring is provided in the sealing groove.

5. The voltage breakdown strength testing fixture for insulating materials according to claim 1, characterized in that: The insulating can is a cylindrical shape with an open top. The two slots are opposite each other along the diameter of the inner cavity of the insulating can, and the slots extend upward to the upper surface of the insulating can.

6. The voltage breakdown strength testing fixture for insulating materials according to claim 1, characterized in that: The test sample (11) is circular. The bottom edge of the slot near the inner cavity of the insulating tank forms a support point for the test sample. The distance between the support points of the two slots and the axis of the fixed metal electrode is equal, and both are equal to the radius of the test sample.

7. The voltage breakdown strength testing fixture for insulating materials according to claim 1, characterized in that: The width of the card slot is 4~5mm.

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