Fixing device

Abstract

The present application relates to a fixing device. The device includes a pressing member, a first support block, and a second support block. The first support block includes an arc-shaped protruding portion, and the second support block includes an arc-shaped groove, and the protruding portion cooperates with the groove; a space for accommodating an arc-shaped test piece can be formed between the first support block and the second support block; the pressing member is used to apply pressure to the first support block and the second support block, so that the first support block and the second support block clamp the accommodated arc-shaped test piece; electrical connectors are arranged at both ends of the protruding portion, and the electrical connectors are used to contact both ends of the arc-shaped test piece accommodated between the first support block and the second support block and are used to be electrically connected to an external testing device. Using this fixing device can improve the test accuracy of the self-healing characteristics of the double-layer film in the metallized capacitor.

Description

Technical Field

[0001] This application relates to the technical field of high-voltage testing of power capacitors, and particularly to a fixing device. Background Art

[0002] The metallized film capacitor is wound by a metallized double-layer polypropylene film with a metal alloy sprayed on one side, and is widely used in flexible DC transmission systems to enable the normal operation of the flexible DC transmission system. Due to the existence of electrical weak points or impurities inside the film, these parts will be instantaneously broken down during operation, and the metal layer on the film surface will evaporate until insulation is restored again. This phenomenon is called self-healing. It is crucial to study the self-healing characteristics of metallized film capacitors that conform to the actual working conditions.

[0003] In traditional technologies, usually, the method of changing the relative positions of the double-layer films is adopted. The double-layer films are arranged in a staggered manner to expose the electrode lead-out parts, and heavy objects are used to press the overlapping area as the actual effective capacitance area, and the rest of the film parts are suspended to study the self-healing characteristics of the film.

[0004] However, in traditional technologies, there is an air gap between the double-layer films in the suspended area, and the pressurized test is likely to cause ionization of the air gap, resulting in breakdown in the non-effective capacitance area (the single-layer film part where the electrode is exposed after staggering), thus affecting the accuracy of the self-healing characteristic test. Summary of the Invention

[0005] Based on this, it is necessary to provide a fixing device that can improve the accuracy of the self-healing characteristic test of the double-layer film in the metallized capacitor for the above technical problems.

[0006] A fixing device, which includes a pressurizing member, a first support block, and a second support block. The first support block includes an arc-shaped protruding part, and the second support block includes an arc-shaped groove, and the protruding part cooperates with the groove; a space for accommodating an arc-shaped test piece can be formed between the first support block and the second support block; the pressurizing member is used to apply pressure to the first support block and the second support block so that the first support block and the second support block clamp the accommodated arc-shaped test piece; electrical connection members are arranged at both ends of the protruding part, and the electrical connection members are used to contact both ends of the arc-shaped test piece accommodated between the first support block and the second support block and are used to be electrically connected to an external testing device.

[0007] In one embodiment, the arc-shaped test piece includes a double-layer film and two shapeable plates respectively arranged on both sides of the double-layer film.

[0008] In one embodiment, metal layers are sprayed on partial areas of each layer of the double-layer film.

[0009] In one embodiment, conductive parts are respectively arranged at two ends of the first deformable plate that contacts the metal layer among the two deformable plates, and the conductive parts contact the metal layer and also contact the electrical connector.

[0010] In one embodiment, the pressing member includes a bottom plate, a bracket arranged on the bottom plate, and a fastener. The second support block is connected to the bracket through the fastener; when the fastener is in a loosened state, the second support block can slide on the bracket; when the fastener is in a tightened state, the second support block is fixed on the bracket.

[0011] In one embodiment, the fastener includes a fastening slider and a fastening bolt. The fastening slider is connected to the second support block. A through hole is arranged in the fastening slider, and the fastening slider is sleeved on the bracket through the through hole. The fastening slider and the fastening bolt are in threaded cooperation.

[0012] In one embodiment, the material of the deformable plate is PVC material.

[0013] In one embodiment, the device further includes a lighting assembly for irradiating the arc-shaped test piece accommodated between the first support block and the second support block.

[0014] In one embodiment, the double-layer film is the film in a metallized film capacitor, and the double-layer film is a metallized polypropylene film or an in-series metallized polypropylene film.

[0015] In one embodiment, the conductive part is a conductive tape.

[0016] The above-mentioned fixing device accommodates the arc-shaped test piece through the first support block and the second support block. Therefore, the double-layer film for self-healing property testing can be placed in the arc-shaped test piece for testing. Among them, since the convex part between the first support block and the second support block cooperates with the groove, the formed accommodating environment is the same as the environment of the double-layer film in the metallized capacitor. Therefore, it is more in line with the actual structure of the double-layer film arranged in the capacitor, ensuring the accuracy of the test. At the same time, since there is a pressing member applying pressure to the first support block and the second support block to clamp the accommodated arc-shaped test piece, the air gap between the double-layer films can be avoided, thus avoiding the situation where the test data is affected by air gap ionization. In addition, since electrical connectors are arranged at both ends of the convex part and the electrical connectors are in contact with both ends of the arc-shaped test piece, the voltage can be directly applied to the double-layer film maintaining the original structure in the arc-shaped test piece through the electrical connectors for testing without misaligning the double-layer film. Therefore, the situation where the non-effective capacitance area breaks down will not occur, effectively ensuring the accuracy of the test data, greatly improving the accuracy of the self-healing property test, and providing a more effective test platform for studying the self-healing property of the double-layer film capacitor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic structural diagram of the fixing device in one embodiment;

[0018] Figure 2 is a schematic structural diagram of the arc-shaped test piece in one embodiment;

[0019] Figure 3 is a schematic structural diagram of the metallized film capacitor in one embodiment;

[0020] Figure 4 is a schematic structural diagram of another metallized film capacitor in one embodiment;

[0021] Figure 5 is a schematic structural diagram of another arc-shaped test piece in one embodiment;

[0022] Figure 6 is a schematic structural diagram of the pressing member in one embodiment;

[0023] Figure 7 is a schematic structural diagram of the film pressing test fixture in one embodiment. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0024] In order to make the objectives, technical solutions and advantages of the present application clearer, the present application will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present application and are not used to limit the present application.

[0025] In the description of the application, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the present invention.

[0026] In addition, the terms "first" and "second" are only used for descriptive purposes and should not be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present invention, the meaning of "a plurality" is at least two, such as two, three, etc., unless otherwise specifically and clearly defined.

[0027] In this application, unless otherwise clearly specified and limited, terms such as "mounted", "connected", "connected to", "fixed" should be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or integrated; it may be a mechanical connection or an electrical connection; it may be directly connected or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements, unless otherwise clearly limited. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0028] In the present invention, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature may be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over" and "on top of" the second feature may be that the first feature is directly above or obliquely above the second feature, or merely indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "beneath" and "underneath" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely indicates that the first feature has a lower horizontal height than the second feature.

[0029] It should be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used in this article are only for illustrative purposes and do not represent the only implementation.

[0030] The metallized film capacitor is wound by a double-layer polypropylene film sprayed with a metal alloy on one side and is widely used in flexible DC transmission systems. Ensuring the safe and stable operation of the metallized film capacitor is of great significance to flexible DC transmission projects. Among them, due to the existence of electrical weaknesses or impurities inside the metallized film capacitor, these parts will instantaneously break down during operation, and the metal layer on the surface of the dielectric will evaporate until insulation is restored. This phenomenon is called self-healing. Studying the self-healing characteristics of the metallized film capacitor that conforms to the actual working conditions is crucial for flexible DC transmission projects.

[0031] Applying a complex voltage to the metallized polypropylene film can study the self-healing characteristics of the metallized polypropylene film at the film sample level. Due to the special nature of the double-layer tightly wound structure of the metallized polypropylene film, it is difficult to apply a voltage without changing the true structure of the double-layer film.

[0032] In the related art, in the experiment of studying the self-healing characteristics, when applying voltage to a metallized polypropylene film, a method of changing the relative position of the double-layer film is usually adopted, that is, arranging the double-layer film in a staggered manner to expose the electrode lead-out part (i.e., the metallized layer), and the rest of the film part is suspended. The problems of this method are as follows: First, the double-layer metallized polypropylene films are not all closely attached, and there is an air gap between the double-layer films in the suspended area. The pressurization test is likely to cause air-gap ionization, and breakdown will occur in the non-effective capacitance area in advance, thus affecting the accuracy of the self-healing characteristic test; Second, the position where the double-layer films are closely corresponding changes, which is quite different from the actual situation, and it is difficult to simulate the area and range where the self-healing point of the metallized film capacitor appears under the actual operating conditions through experiments; Third, for the series-connected metallized film capacitor, the structure of the series-connected metallized polypropylene film determines that the electrode leads of the high-voltage end and the low-voltage end are both on the same film, and it has not been verified whether the above method can be applied to this kind of film structure. In addition, in the above method, due to the special structure of the film-level capacitor, the thickness of the polypropylene film is only in the micron level, the film is prone to wrinkles and breakages, and the two electrodes of the film-level capacitor are actually distributed on two films. Therefore, it is difficult to directly add electrodes while maintaining the structure of the film capacitor. If directly using the upper and lower opposite plate-plate electrodes to press the double-layer film tightly, after the first self-healing occurs, although the metallized layer at the breakdown point has been removed, the plate-plate electrodes still closely adhere to the surface of the metallized film, resulting in the actual conduction state between the upper and lower electrodes at the breakdown point, and the film-level capacitor cannot restore insulation, affecting the test of the self-healing characteristics; moreover, when there is an air layer between the double-layer films, air-gap ionization will occur first in the air-gap part, and normal self-healing cannot occur.

[0033] In view of this, an embodiment of the present application provides a fixing device, which is used to improve the accuracy of the self-healing characteristic test of the double-layer polypropylene film by using this device.

[0034] In one embodiment, as Figure 1 shown, it shows a schematic structural diagram of a fixing device provided by an embodiment of the present application. The fixing device includes a pressurizing member 101, a first support block 102, and a second support block 103. The first support block 102 includes an arc-shaped protruding portion, and the second support block 103 includes an arc-shaped groove, and the protruding portion cooperates with the groove; a space for accommodating an arc-shaped test piece can be formed between the first support block 102 and the second support block 103; the pressurizing member 101 is used to apply pressure to the first support block 102 and the second support block 103 so that the first support block 102 and the second support block 103 clamp the accommodated arc-shaped test piece; electrical connectors 104 are arranged at both ends of the protruding portion, and the electrical connectors 104 are used to contact both ends of the arc-shaped test piece accommodated between the first support block 102 and the second support block 103 and are used to be electrically connected to an external test device.

[0035] Among them, the cooperation between the convex portion of the first support block 102 and the groove of the second support block 103 means that the surface curvature of the convex portion is the same as that of the groove. At the same time, the arc-shaped test piece is accommodated between the convex portion of the first support block 102 and the groove of the second support block 103. Therefore, the curvature of the arc-shaped test piece is the same as the surface curvatures of the convex portion and the groove, so that when the pressing member 101 clamps the accommodated arc-shaped test piece with the first support block 102 and the second support block 103, the air in the arc-shaped test piece can be effectively excluded. Therefore, the double-layer film for self-healing property testing can be located in the middle of the arc-shaped test piece. When the pressing member 101 clamps the accommodated arc-shaped test piece with the first support block 102 and the second support block 103, the double-layer film is also clamped, and the air gap in the double-layer film is excluded.

[0036] Exemplarily, in Figure 1 the first support block 102 shown is a semi-cylinder, and the second support block 103 is a cuboid containing a semi-cylindrical depression. Of course, the embodiments of the present application do not specifically limit the shapes of the first support block 102 and the second support block 103. As long as the first support block 102 includes a convex portion, the second support block 103 includes a depression, and the surface curvature of the convex portion of the first support block 102 is the same as the surface curvature of the depression of the second support block 103, the two can fit together. Optionally, the first support block 102 and the second support block 103 can be made of acrylic material. Of course, without affecting the characteristics of the test data, the first support block 102 and the second support block 103 can also be made of other materials, and the embodiments of the present application do not specifically limit this.

[0037] The pressing member 101 is used to apply pressure to the first support block 102 and the second support block 103 so that the first support block 102 and the second support block 103 clamp the accommodated arc-shaped test piece. Optionally, the pressing member 101 can be connected to the first support block 102 and connected to the second support block 103, and the pressure applied to the first support block 102 and the second support block 103 can be adjusted by adjusting the distance between the first support block 102 and the second support block 103. Optionally, the pressing member 101 can be connected to any one of the first support block 102 or the second support block 103. When the other support block is fixed, the pressing member 101 adjusts the pressure applied to the first support block 102 and the second support block 103 by adjusting the position of the connected support block.

[0038] The electrical connector 104 is disposed at both ends of the first support block 102 and contacts both ends of the arc-shaped test piece. Specifically, when the double-layer film is located inside the arc-shaped test piece, both ends of the double-layer film contact both ends of the arc-shaped test piece, and thus can contact the electrical connector 104. Therefore, when the electrical connector 104 is connected to an external power supply, a voltage is applied to the double-layer film to test the self-healing characteristics. As Figure 1 shown, the electrical connector 104 can include two parts, which are respectively connected to both ends of the first support block 102 and further contact both ends of the arc-shaped connector. Optionally, the electrical connector 104 can be a conductive metal, and the electrical connector 104 can be connected to the first support block 102 by bolts. Optionally, the electrical connector 104 can also be disposed at both ends of the second support block 103 and contact both ends of the arc-shaped test piece. By arranging the electrical connector 104 to contact both ends of the arc-shaped test piece, the two electrodes of the double-layer film can be led out from both ends. Therefore, without the operation of exposing the electrodes by dislocation as in the traditional method, the double-layer film can be pressurized, avoiding premature breakdown due to the existence of non-effective capacitance regions in the double-layer film and affecting the test of the self-healing characteristics.

[0039] The above fixing device accommodates the arc-shaped test piece through the first support block and the second support block. Therefore, the double-layer film for testing the self-healing characteristics can be placed in the arc-shaped test piece for testing. Among them, since the convex part between the first support block and the second support block cooperates with the groove, the formed accommodating environment is the same as the environment of the double-layer film in the metallized capacitor. Therefore, it is more in line with the actual structure of the double-layer film arranged in the capacitor, ensuring the accuracy of the test. At the same time, since there is a pressing member applying pressure to the first support block and the second support block to clamp the accommodated arc-shaped test piece, the air gap between the double-layer films can be avoided, thus avoiding the situation of affecting the test data due to air gap ionization. In addition, since electrical connectors are disposed at both ends of the convex part, and the electrical connectors contact both ends of the arc-shaped test piece, the double-layer film maintaining the original structure inside the arc-shaped test piece can be directly connected to an external power supply through the electrical connectors to apply a voltage and conduct a test without misaligning the double-layer film. Therefore, the situation of breakdown in the non-effective capacitance region will not occur either, effectively ensuring the accuracy of the test data, greatly improving the accuracy of the self-healing characteristics test, and providing a more effective test platform for studying the self-healing property of the double-layer film capacitor.

[0040] In one embodiment, as Figure 2As shown, it shows a schematic structural diagram of an arc-shaped test piece provided by an embodiment of the present application. The arc-shaped test piece includes a double-layer film 201 and two plasticizable plates 202 respectively disposed on both sides of the double-layer film. The material of the plasticizable plate 202 is PVC material. A metal layer is sprayed on a partial area of each layer of the double-layer film 201.

[0041] The double-layer film 201 is the film in a metallized film capacitor, and the double-layer film 201 is a metallized polypropylene film or an in-series metallized polypropylene film.

[0042] Among them, the arc-shaped test piece includes two plasticizable plates 202 and a double-layer film 201 placed between the two plasticizable plates 202. The double-layer film 201 is the double-layer film in a metallized film capacitor. Commonly used double-layer films in metallized film capacitors include common metallized polypropylene films or in-series metallized polypropylene films. As Figure 3 shown, it shows a schematic structural diagram of a metallized film capacitor provided by an embodiment of the present application. Figure 3 The metallized film capacitor in [description] is wound by a common metallized polypropylene film. The metallized polypropylene film includes two layers of polypropylene films. A metal layer is vapor-deposited on one side of each layer of polypropylene film, and there is a certain distance from the other edge of the film, which is called the margin area; the margin areas of adjacent two metallized films are distributed on both sides of the capacitor, so that the capacitor electrodes can be led out from both sides of the electrodes respectively. This layout structure can reduce the volume of the capacitor and improve the capacitance energy storage density while ensuring the capacitance of the capacitor, and has been widely produced and applied. As Figure 4 shown, it shows a schematic structural diagram of another metallized film capacitor provided by an embodiment of the present application. Figure 4 The metallized film capacitor in [description] is wound by an in-series metallized polypropylene film. The in-series metallized polypropylene film includes two layers of polypropylene films, and a metal layer is vapor-deposited on one side of each layer of polypropylene film in a preset area. This layout structure is actually composed of two series-connected small capacitor units. The voltage division of each small capacitor unit is relatively low, so the thickness of the dielectric film can be effectively reduced and the production cost can be saved. Of course, the double-layer film used in the metallized film capacitor can also include other types. The embodiment of the present application does not specifically limit the type of the double-layer film 201, as long as it is a double-layer film used in a metallized film capacitor. Among them, Figure 2 the double-layer film 201 exemplified in [description] is an in-series metallized polypropylene film.

[0043] The two shapeable plates 202 included in the arc-shaped test piece can be made of a soft and bendable material, so as to deform when clamped by the first support block 102 and the second support block 103, and fill the space between the first support second support block 103 and the double-layer film 201, thereby effectively removing the air gap, avoiding the occurrence of air gap separation, and improving the test accuracy. Optionally, the shapeable plate 202 can be made of PVC material. Among them, PVC material is a non-crystalline material. PVC material has plasticity, incombustibility, high strength resistance and excellent geometric stability. Therefore, a PVC plate can be used as the shapeable plate 202 to play a role in removing the air gap between the first support block 102 and the second support block 103. Specifically, when in use, the double-layer film 201 can be placed between the two shapeable plates 202 to form a sandwich structure, and the two shapeable plates 202 can be wound into an arc shape consistent with the radian of the convex part of the first support block 102, aiming to remove the air between the double-layer film 201 and the two shapeable plates 202.

[0044] It should be noted that Figure 2 only exemplarily shows the composition of the arc-shaped test piece. For the convenience of display, Figure 2 the arc-shaped test piece in has no radian. However, in fact, as mentioned above, the radian of the arc-shaped test piece in the embodiment of the present application is the same as the radian of the convex part of the first support module.

[0045] In the embodiment of the present application, since the arc-shaped test piece is placed between the first support block and the second support block and clamped, on the basis of providing the actual application environment, the air in the experimental environment is effectively removed, avoiding the occurrence of air gap ionization caused by the air gap between the double-layer films and the phenomenon that the double-layer film cannot recover insulation after self-healing, and effectively improving the accuracy of the self-healing characteristic test.

[0046] In one embodiment, as Figure 5 shown, it shows a schematic structural diagram of another arc-shaped test piece provided by the embodiment of the present application. Conductive parts 203 are respectively arranged at both ends of the first shapeable plate in contact with the metal layer among the two shapeable plates, and the conductive parts 203 are in contact with the metal layer, and the conductive parts 203 are also in contact with the electrical connector 104. The conductive part 203 is a conductive tape.

[0047] Among them, to ensure that the electrical connector 104 can be in full contact with the two electrodes of the double-layer film in the arc-shaped test piece, conductive parts 203 are respectively provided at both ends of the first deformable plate of the arc-shaped test piece, and both ends of the conductive part 203 are in contact with both ends of the double-layer film. Optionally, when the electrical connector 104 is arranged at both ends of the first support block 102 and connected to the first support block 102, the first deformable plate refers to the deformable plate in the arc-shaped test piece that contacts the first support block 102. Therefore, when the arc-shaped test piece is clamped between the first support block 102 and the second support block 103, the electrical connectors 104 at both ends of the first support block 102 are respectively in contact with the conductive parts 203 at both ends of the arc-shaped test piece. Optionally, if the electrical connector 104 is arranged at both ends of the second support block 103, correspondingly, the first deformable plate refers to the deformable plate in the arc-shaped test piece that contacts the second support block 103, so as to ensure that the conductive part 203 can be in full contact with the electrical connector 104 and ensure the reliability of the contact.

[0048] Therefore, since the two electrodes at both ends of the double-layer film are respectively in contact with both ends of the conductive part 203, and both ends of the conductive part 203 are respectively in contact with both ends of the electrical connector 104, the two electrodes of the double-layer film can be led out. When the electrical connector 104 is connected to an external power supply, a voltage can be applied to the double-layer film, effectively improving the reliability of contacting the two electrodes at both ends of the double-layer film, thereby further improving the accuracy of obtaining parameters such as current or voltage of the double-layer film in the self-healing characteristic test, and further providing a reliable test platform for improving and studying the aging characteristics of metallized film capacitors under actual conditions.

[0049] Optionally, the conductive part can be realized by spraying a metal layer. Or, the conductive part can be a conductive tape, which is a metal foil or conductive cloth with a highly conductive adhesive backing, that is, the conductive tape can be wound around both ends of the first deformable plate to form the conductive part. Among them, since the thickness of the polypropylene film is only in the micron range, therefore, to ensure the test accuracy, the smaller the thickness of the selected conductive tape, the better.

[0050] In one embodiment, as Figure 6 shown, it shows a schematic structural diagram of a pressing member provided by an embodiment of the present application. The pressing member 101 includes a bottom plate 601, a bracket 602 arranged on the bottom plate 601, and a fastener 603. The second support block 103 is connected to the bracket 602 through the fastener 603; when the fastener 603 is in a loosened state, the second support block 103 can slide on the bracket 602; when the fastener 603 is in a tightened state, the second support block 103 is fixed on the bracket 602.

[0051] The fastener 603 includes a fastening slider 604 and a fastening bolt 605. The fastening slider 604 is connected to the second support block 103. A through hole is provided in the fastening slider 604, and the fastening slider 604 is sleeved on the bracket 602 through the through hole. The fastening slider 604 and the fastening bolt 605 are in threaded cooperation.

[0052] Among them, the fastening slider 604 in the fastener 603 in the pressing member 101 is sleeved on the bracket 602 through a through hole, and the fastener 603 adjusts itself to a tightened state or a loosened state through the fastening bolt 605. Moreover, the fastener 603 is connected to the second support block 103 through the fastening slider 604. The first support block 102 can be fixed on the bottom plate 601 in the pressing member 101. When it is necessary to adjust the pressure between the first support block 102 and the second support block 103, that is, after an arc-shaped test piece is placed on the first support block 102, when the fastening bolt 605 in the fastener 603 is loosened, the second support block 103 can be moved to slide on the bracket 602 to shorten the distance between the first support block 102 and the second support block 103, so that the first support block 102 and the second support block 103 are as close as possible in contact. And when the pressure is appropriate, the fastening bolt 605 is tightened to keep the pressure between the first support block 102 and the second support block 103 stable, providing a test environment for further self-healing testing of the double-layer film. After the test is completed, when the fastening bolt 605 is loosened, the fastening slider 604 can be slid to adjust the distance between the second support block 103 and the first support block 102 to take out the arc-shaped test piece.

[0053] Optionally, the pressure test component can also be connected to the first support block 102 or the second support block 103, so as to test the pressure between the first support module and the second support module in real time through the pressure test component, in order to provide the most suitable pressure for the arc-shaped test piece and further improve the accuracy of the test data. For example, the pressure test component can be a sensor, and the pressure test component can be in contact with the surface of the convex part or the concave groove to obtain the pressure data between the first support block 102 and the second support block 103.

[0054] Optionally, the pressure test component can also be composed of a distance sensor and a processor. The distance sensor can obtain the distance parameter between the first support block 102 and the second support block 103 and send it to the processor. Multiple groups of corresponding relationships between the distance parameter and the pressure magnitude are pre-stored in the processor, and the pressure magnitude between the first support block 102 and the second support block 103 is determined according to the received distance parameter.

[0055] In one embodiment, the device further includes an illumination component for irradiating the arc-shaped test piece accommodated between the first support block 102 and the second support block 103.

[0056] Among them, the fixing component 100 may further include an illumination component to irradiate the arc-shaped test piece accommodated between the first support block 102 and the second support block 103 during the test, so as to facilitate observing the change in the surface morphology of the double-layer film, and timely adjusting the pressing component 101 to provide an appropriate pressure. Optionally, the illumination component may be composed of a constantly-on LED lamp and a base. Optionally, the illumination component may be located on the side where the first support module contacts the floor of the pressing component 101 to provide a better irradiation environment, facilitate observing the change in the surface morphology of the double-layer film, and provide a more reliable test environment.

[0057] In one embodiment, as Figure 7 shown, it shows a schematic structural diagram of a film pressing test fixture provided by an embodiment of the present application. The film pressing test fixture includes a first support block 701, a second support block 702, a first PVC board 703, a second PVC board 704, a pressing component, a metal conductive component 706, and an illumination component 707. The pressing component includes a bottom plate 708, a bracket 709 provided on the bottom plate 708, and a fastening bolt 710.

[0058] Among them, a double-layer film for self-healing characteristic test can be placed between the first PVC board 703 and the second PVC board 704. The double-layer film is a metallized polypropylene double-layer film in a metallized film capacitor. Optionally, the double-layer film can be a metallized polypropylene film or an in-series metallized polypropylene film. The first PVC board 703 and the second PVC board 704 are used to press the double-layer film between them and wind it into a semi-circular arc shape after placing the double-layer film to exhaust the air between the films and between the films and the PVC boards, forming an arc-shaped test piece. At the same time, metal layers are sprayed on the two semi-circular arc sides of the first PVC board 703 or conductive tapes are wound around them, and they are respectively in contact with the two electrode ends of the double-layer film to lead out the high and low potentials at both ends of the double-layer film.

[0059] The first support block 701 includes an arc-shaped protrusion, and the second support block 702 includes an arc-shaped groove, and the protrusion cooperates with the groove; a space for accommodating the arc-shaped test piece can be formed between the first support block 701 and the second support block 702. Specifically, the first support block 701 is semi-cylindrical in shape, and the second support block 702 is a cuboid containing a semi-cylindrical depression. The arc-shaped test piece composed of the first PVC plate 703, the second PVC plate 704 and the double-layer film can be clamped between the first support block 701 and the second support block 702. At the same time, the metal conductive part 706 includes two metal conductive parts, and the two metal conductive parts are respectively connected to both ends of the first support block 701 by bolts. When the arc-shaped test piece contacts the first support block 701, the two metal conductive parts are respectively in contact with the metal layers or conductive tapes at both ends of the first PVC plate 703 to realize electrode lead-out. When the metal conductive part 706 is connected to an external power supply, a voltage is applied to the double-layer film when the external power supply is turned on.

[0060] The pressing member is used to apply pressure to the first support block 701 and the second support block 702 so that the first support block 701 and the second support block 702 clamp the accommodated arc-shaped test piece. Optionally, the applied pressure can be as large as possible to exclude air in the arc-shaped test piece to a great extent. Specifically, the pressing member includes a bottom plate 708, a bracket 709 provided on the bottom plate 708, and a fastening bolt 710. The second support block 702 is connected to the bracket 709; when the fastening bolt 710 is in a loosened state, the second support block 702 can slide on the bracket 709; when the fastening bolt 710 is in a tightened state, the second support block 702 is fixed on the bracket 709. Among them, the bracket 709 and the fastening bolt 710 are in threaded cooperation to be tightened or loosened.

[0061] The lighting assembly 707 is used to irradiate the arc-shaped test piece accommodated between the first support block 701 and the second support block 702 to provide a lighting environment for observing the change of the surface morphology of the double-layer film during the test process. Optionally, the lighting assembly 707 can be composed of a constantly-on LED lamp and a fixed base, and is located on the side where the first support block 701 contacts the pressing member, that is Figure 7 below the first support block 701 in

[0062] The film pressure test fixture provided by the embodiments of the present application takes into account the actual arrangement structure of the double-layer metallized polypropylene film in the metallized film capacitor, and designs a new pressure test fixture for the metallized polypropylene film sample. On the basis of keeping the original tightly fitting structure of the double-layer metallized polypropylene film unchanged, through the way of electrode lead-out, the voltage injection of the double-layer film structure sample is realized. This pressure test fixture can ensure that the double-layer polypropylene films are closely corresponding, conform to the actual structure inside the metallized film capacitor, and can effectively avoid the air gap ionization caused by the air gap between the double-layer films and the phenomenon that the insulation cannot be restored after the self-healing of the double-layer films, providing a more effective test platform and sample arrangement method for studying the self-healing characteristics of film capacitors.

[0063] Among them, the process of using this film pressure test fixture to test the self-healing characteristics of the double-layer film includes:

[0064] Step 1, select the metallized film capacitor to be tested, peel off the metallized polypropylene double-layer film with a double-layer winding structure from it, cut a rectangular film of appropriate size, and ensure that the double-layer film sample maintains the original structure.

[0065] Step 2, judge the metal surface on the outside of the double-layer film sample, cover this metal surface on the first PVC plate with gold spraying on the bilateral semi-circular side edges, and ensure that the metal surface is closely attached to the gold spraying position on the bilateral semi-circular side edges to realize electrode lead-out.

[0066] Step 3, cover the second PVC plate above the double-layer film sample, so that the two semi-circular PVC plates clamp the double-layer film structure sample to form a semi-circular "sandwich structure".

[0067] Step 4, combine the first support block and the second support block with the pressure member, fix the first support block on the bottom plate of the pressure member with bolts, fix the second support block on the bracket, and adjust the position of the second support block on the bracket by rotating the fastening bolt;

[0068] Step 5, use the first support block and the second support block to fix the "sandwich structure" in Step 3, cover the "sandwich structure" on the first support block, the gold-sprayed part of the first PVC plate corresponds to the metal conductive parts at both ends connected by the first support block, and rotate the fastening bolt to make the second support block press the "sandwich structure".

[0069] Step 6, the metal conductive parts at both ends of the first support block are externally connected to the high-voltage end and the low-voltage end of the power supply to realize the voltage injection of the double-layer film sample, so as to further complete the self-healing characteristic test experiment of the double-layer film structure sample.

[0070] The technical features of the above embodiments can be combined arbitrarily. For the sake of brevity of description, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, it should be considered as the scope described in this specification.

[0071] The above-described embodiments merely represent several implementation manners of the present application. The description thereof is relatively specific and detailed, but it should not be construed as a limitation on the patent scope of the present application. It should be noted that for those of ordinary skill in the art, without departing from the concept of the present application, several modifications and improvements can still be made, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the appended claims.

Claims

1. A fixing device, characterized in that, The device includes a pressing member, a first support block, and a second support block. The first support block includes an arc-shaped protruding portion, and the second support block includes an arc-shaped groove. The protruding portion cooperates with the groove; A space for accommodating an arc-shaped test piece can be formed between the first support block and the second support block; The pressing member is used to apply pressure to the first support block and the second support block so that the first support block and the second support block clamp the accommodated arc-shaped test piece. The arc-shaped test piece includes a double-layer film and two deformable plates respectively arranged on both sides of the double-layer film. The deformable plates are deformed when clamped by the first support block and the second support block; Electric connectors are arranged at both ends of the protruding portion. The electric connectors are used to contact both ends of the arc-shaped test piece accommodated between the first support block and the second support block and are used to be electrically connected to an external test device; The double-layer film is an in-series metallized polypropylene film, and the double-layer film is the film in a metallized film capacitor.

2. The device according to claim 1, wherein The radian of the arc-shaped test piece is the same as the surface radian of the protruding portion and the groove.

3. The device according to claim 1, characterized in that Metal layers are sprayed on partial areas of each layer of the double-layer film.

4. The device according to claim 3, characterized in that, Conductive parts are respectively arranged at both ends of the first deformable plate that contacts the metal layer among the two deformable plates. Moreover, the conductive parts contact the metal layer, and the conductive parts also contact the electric connectors.

5. The device according to claim 1, characterized in that, The pressing member includes a bottom plate, a bracket arranged on the bottom plate, and a fastener. The second support block is connected to the bracket through the fastener; When the fastener is in a loosened state, the second support block can slide on the bracket; When the fastener is in a tightened state, the second support block is fixed on the bracket.

6. The device according to claim 5, characterized in that, The fastener includes a fastening slider and a fastening bolt. The fastening slider is connected to the second support block. A through hole is arranged in the fastening slider. The fastening slider is sleeved on the bracket through the through hole, and the fastening slider and the fastening bolt are in threaded cooperation.

7. The device according to any one of claims 1 to 4, characterized in that The material of the deformable plate is PVC material.

8. The device according to claim 1, characterized in that, The device further includes an illumination component, and the illumination component is used to irradiate the arc-shaped test piece accommodated between the first support block and the second support block.

9. The device according to claim 4, characterized in that The conductive part is conductive tape.

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