Equipment and method for preparing epoxy impregnated paper sample

Abstract

The invention discloses equipment for preparing an epoxy impregnated paper sample, the equipment comprises a mold, an epoxy resin casting material and a vacuum oven, the mold comprises two groups of symmetrically arranged mold main bodies, and the two groups of mold main bodies are fixed by fasteners; pouring cavities are formed in the opposite sides of the mold main bodies, tightened crepe paper is clamped between the two mold main bodies, two sample electrodes are symmetrically arranged in the two pouring cavities, and pouring intervals are formed between the opposite ends of the two sample electrodes and the crepe paper; the epoxy resin pouring material is vacuumized in the vacuum oven and then poured into the pouring cavity; and the mold poured with the epoxy resin pouring material is vacuumized in a vacuum oven. By utilizing the equipment disclosed by the invention, the stretching state of the crepe paper can be effectively controlled, the introduction of bubbles is reduced, a test sample with equivalent insulation characteristics with an actual epoxy impregnated paper sleeve is prepared, and a technical support is provided for accurately evaluating the related performance of an epoxy impregnated paper insulating material.

Description

Technical Field

[0001] This invention belongs to the field of electrical equipment insulation material testing technology, specifically relating to an apparatus and method for preparing epoxy impregnated paper samples. Background Technology

[0002] High-voltage bushings are key equipment in ultra-high voltage power transmission projects, and their safe operation plays an important role in ensuring the reliability of the power transmission system.

[0003] The capacitor core, serving as the main insulation of the bushing, uses epoxy-impregnated paper composite material as its dielectric. This material is formed by winding insulating paper and then vacuum impregnating and curing it with epoxy resin, thus undertaking a crucial part of the bushing's internal insulation. During operation, the high-voltage bushing is subjected to the combined effects of electrical, thermal, and mechanical stresses. Therefore, it is necessary to simulate the operating conditions of the epoxy-impregnated paper inside the core during preliminary work to conduct subsequent tests and studies on its dielectric, thermal, and mechanical properties. Currently, prepared epoxy-impregnated paper samples are typically used for these tests and studies.

[0004] In existing technologies, when using high-temperature compression molding to prepare epoxy impregnated paper samples, there are problems such as failure to build a vacuum environment and improper application of external force. During the epoxy resin impregnation and curing process, too many air bubbles are easily introduced, causing partial discharge and insulation deterioration. The prepared samples cannot truly simulate the internal structure of the actual bushing core. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide an apparatus and method for preparing epoxy impregnated paper samples, which addresses the shortcomings of the prior art. By controlling the stretching state of the crepe paper and reducing the introduction of air bubbles, a test sample with equivalent insulation characteristics to the actual epoxy impregnated paper sleeve is prepared, thereby solving the technical problem that the samples prepared in the prior art cannot truly simulate the internal structure of the actual sleeve core.

[0006] The present invention adopts the following technical solution: an apparatus for preparing epoxy impregnated paper samples, comprising a mold, epoxy resin casting material and a vacuum oven, wherein the mold comprises two sets of symmetrically arranged mold bodies, and the two sets of mold bodies are fixed by fasteners; The mold body is provided with a casting cavity on the opposite side, and a taut crepe paper is sandwiched between the two mold bodies. Sample electrodes are symmetrically arranged in the two casting cavities, and a casting interval is provided between the opposite ends of the two sample electrodes and the crepe paper. The epoxy resin casting material is poured into the casting cavity after being evacuated in a vacuum oven; the mold containing the epoxy resin casting material is evacuated in a vacuum oven.

[0007] Preferably, the mold body includes an inner cavity and an outer plate. The upper end of the inner cavity is provided with a U-shaped opening extending from top to bottom. The U-shaped opening forms the casting cavity, and the outer end of the sample electrode is fixed to the outer plate.

[0008] Preferably, the upper and lower ends of the inner cavity and the outer plate are respectively provided with fixing holes, and the fastener includes a bolt assembly that passes through the fixing holes.

[0009] Preferably, the outer plate has mounting holes at the positions corresponding to the sample electrode, and the sample electrode is fixedly assembled onto the outer plate by fixing bolts passing through the mounting holes.

[0010] Preferably, the gaps between the two sets of mold bodies are coated with silicone rubber.

[0011] Preferably, multiple casting cavities are spaced apart along the length of the mold body.

[0012] Another technical solution of the present invention is a method for preparing epoxy-impregnated paper samples, comprising the following steps: The crepe paper was placed in a vacuum oven and dried under vacuum conditions. The prepared epoxy resin casting material was placed in a vacuum oven and evacuated. The sample electrodes are fixed in the casting cavities of the two mold bodies respectively. The crepe paper is placed between the two mold bodies in a taut state. The crepe paper is clamped between the two mold bodies. The two mold bodies are fixed with fasteners to complete the mold assembly. Pour the prepared epoxy resin casting material into the casting cavity, and then place the mold in a vacuum oven and vacuum it at room temperature. Start the curing process. After curing is complete, remove the mold and obtain the required sample.

[0013] Preferably, the epoxy resin casting material includes epoxy resin, curing agent methyltetrahydrophthalic anhydride, and accelerator N,N-dimethylbenzylamine; The epoxy resin was placed in an oven at 50°C for insulation one day before preparation. The epoxy resin, curing agent and accelerator are mixed in proportion and then stirred at 400 r / min in an oil bath at 60°C. After mixing, the mixture is placed in a vacuum oven and vacuumed for 3-4 hours.

[0014] Preferably, silicone rubber is applied to the gap between the two mold bodies, and after completion, the mold is placed in a 110°C oven for heat preservation for 3-4 hours.

[0015] Preferably, the mold is placed in a vacuum oven and vacuumed at room temperature for 3-4 hours.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: The vacuum oven can perform vacuum treatment on epoxy resin casting materials and molds after casting. The two vacuum treatments target the epoxy resin casting materials and the molds after casting, respectively. This double protection effectively removes air bubbles introduced into the epoxy resin system and casting process, ensuring that the internal structure of the sample is dense and improving the structural consistency between the sample and the actual epoxy impregnated paper. It solves the problem of the lack of a vacuum environment in existing sample preparation methods and reduces the risk of partial discharge and insulation degradation.

[0017] The casting cavity provides a filling space for the epoxy resin casting material, ensuring that the epoxy resin material evenly wraps the crepe paper. The taut crepe paper can simulate the state of the insulating paper in the actual epoxy impregnated sleeve, making the insulation characteristics of the sample closer to the actual product and providing an equivalent sample for subsequent performance testing.

[0018] The symmetrically arranged sample electrodes provide stable conductors for the high-voltage and grounding ends of the sample, ensuring the smooth conduction of subsequent dielectric performance tests. The casting interval ensures that the epoxy resin casting material can fill the space between the electrodes and the crepe paper, simulating the interaction structure between the electrodes and insulating material in a real core.

[0019] Furthermore, the mold body is divided into an inner cavity and an outer plate. The inner cavity is used to construct the casting space, while the outer plate facilitates the fixing of the sample electrode and provides support for mold assembly. The structural design is reasonable and facilitates loading and unloading. The inner cavity is provided with a U-shaped opening extending from top to bottom to form a casting cavity, which facilitates the casting of epoxy resin casting material and ensures that the epoxy resin casting material evenly covers the crepe paper during the casting process.

[0020] Furthermore, silicone rubber can effectively seal the gaps between the mold bodies, preventing liquid epoxy resin from leaking along the bottom and side gaps, thus reducing material waste and incomplete sample structure. It also prevents external air from entering the casting cavity through the gaps, avoiding the introduction of new air bubbles.

[0021] Furthermore, multiple casting cavities can be used to prepare multiple samples at once, greatly improving sample preparation efficiency.

[0022] In summary, the preparation apparatus and method of this application can effectively control the stretching state of crepe paper and reduce the introduction of air bubbles, thus preparing test specimens with equivalent insulation properties to actual epoxy-impregnated paper sleeves, providing technical support for accurately evaluating the relevant performance of epoxy-impregnated paper insulation materials.

[0023] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0024] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the following description of the relative embodiments will be briefly introduced. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0025] Figure 1 This is an exploded view of the mold in this invention; Figure 2 This is a schematic diagram of the sample electrode structure in this invention; Figure 3 This is a schematic diagram of the mold in the present invention from the frontal explosion direction; Figure 4 This is a schematic diagram of the assembly of the mold and the crepe paper in this invention; Figure 5 This is a schematic diagram of the mold after curing (with the outer panel removed) in this invention; Figure 6 A schematic diagram of the completed sample preparation; Figure 7 This is a front view of the completed sample.

[0026] The components are: 1. Mold; 11. Mold body; 111. Inner cavity; 112. Outer plate; 113. Casting cavity; 114. Fixing perforation; 115. Mounting hole; 2. Crepe paper; 3. Sample electrode. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "one side," "one end," and "one side," etc., indicating orientation or positional relationships based on the orientation or positional relationships shown in the accompanying drawings, are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0029] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0030] It should be understood that, when used in this specification and the appended claims, the terms "comprising" and "including" indicate the presence of the described features, integrals, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or collections thereof.

[0031] It should also be understood that the terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to limit the invention. As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” are intended to include the plural forms unless the context clearly indicates otherwise.

[0032] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0033] The accompanying drawings illustrate various structural schematic diagrams according to embodiments disclosed in this invention. These drawings are not to scale, and some details have been enlarged for clarity, and some details may have been omitted. The shapes of the various regions and layers shown in the drawings, as well as their relative sizes and positional relationships, are merely exemplary and may deviate from reality due to manufacturing tolerances or technical limitations. Furthermore, those skilled in the art can design regions / layers with different shapes, sizes, and relative positions as needed.

[0034] This invention provides an apparatus for preparing epoxy-impregnated paper samples, which can effectively control the tensile state of the crepe paper 2 and reduce the introduction of air bubbles, thus preparing test samples with equivalent insulation properties to actual epoxy-impregnated paper sleeves, providing technical support for accurately evaluating the relevant performance of epoxy-impregnated paper insulation materials.

[0035] like Figure 4 As shown, in this embodiment, the front-back direction is the length direction of mold 1, and the left-right direction is the width direction of mold 1.

[0036] Please see Figures 1 to 7 The present invention discloses an apparatus for preparing epoxy impregnated paper samples, comprising a mold 1, an epoxy resin casting material and a vacuum oven. The mold 1 comprises two sets of symmetrically arranged mold bodies 11, which are fixed together by fasteners to form the mold 1.

[0037] like Figure 1 , 4 As shown, casting cavities 113 are provided on opposite sides of the mold body 11, and taut crepe paper 2 is sandwiched between the two mold bodies 11. The opposite sides of the casting cavities 113 are connected to the crepe paper 2. A sample electrode 3 is provided in each casting cavity 113. The sample electrodes 3 in the two casting cavities 113 are arranged symmetrically with the crepe paper 2 as the center, and the sample electrodes 3 and the crepe paper 2 are spaced apart, so that a casting interval is formed between the sample electrodes 3 and the crepe paper 2.

[0038] Specifically, in this embodiment, the distance between the opposite ends of the two sample electrodes 3 is 1 mm, and the thickness of the crepe paper 2 is a conventional thickness of 0.3 mm, resulting in the casting interval. In other embodiments, sample electrodes 3 of other sizes can be designed according to actual experimental requirements to control the casting interval.

[0039] The symmetrically arranged sample electrodes 3 provide stable conductors for the high voltage and grounding ends of the sample, ensuring the smooth conduction of subsequent dielectric performance tests. The casting interval is designed to ensure that the epoxy resin casting material can fill between the electrodes and the crepe paper 2, simulating the interaction structure between the electrodes and insulating material in a real core.

[0040] The casting cavity 113 provides a filling space for the epoxy resin casting material, ensuring that the epoxy resin material evenly wraps the crepe paper 2. The taut crepe paper 2 can simulate the state of the insulating paper in the actual epoxy impregnated sleeve, making the insulation characteristics of the sample closer to the actual product, and providing an equivalent sample for subsequent performance testing.

[0041] In this embodiment, the epoxy resin casting material is poured into the casting cavity 113 after being evacuated in a vacuum oven. The mold 1 containing the epoxy resin casting material is then evacuated in a vacuum oven.

[0042] The vacuum oven can perform vacuum treatment on the epoxy resin casting material and the mold 1 after casting. The two vacuum treatments are performed on the epoxy resin casting material and the mold 1 after casting, respectively. This double protection effectively removes air bubbles introduced into the epoxy resin system and casting process, ensuring that the internal structure of the sample is dense, improving the structural consistency between the sample and the actual epoxy impregnated paper, solving the problem of the lack of a vacuum environment in existing sample preparation methods, and reducing the risk of partial discharge and insulation degradation.

[0043] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0044] Please see Figures 1 to 7 In the apparatus for preparing epoxy-impregnated paper samples of the present invention, preferably, the mold body 11 includes an inner cavity 111 and an outer plate 112. The upper end of the inner cavity 111 is provided with a U-shaped opening extending from top to bottom, with the left and right sides of the U-shaped opening being continuous, forming a casting cavity 113. The outer end of the sample electrode 3 is fixed to the outer plate 112, and the inner side of the sample electrode 3 extends into the casting cavity 113.

[0045] The mold body 11 is divided into an internal cavity 111 and an outer plate 112. The internal cavity 111 is used to construct the casting space, while the outer plate 112 facilitates the fixing of the sample electrode 3 and provides support for the assembly of the mold 1. The structural design is reasonable and facilitates loading and unloading. The internal cavity 111 is provided with a U-shaped opening extending from top to bottom to form a casting cavity 113, which facilitates the casting of epoxy resin casting material and ensures that the epoxy resin casting material evenly covers the crepe paper 2 during the casting process.

[0046] Preferably, in this embodiment, the upper and lower ends of the inner cavity 111 and the outer plate 112 are respectively provided with fixing holes 114, and the fasteners include bolt assemblies that pass through the fixing holes 114.

[0047] Specifically, such as Figure 1 , 4 As shown, an upward-opening fixing groove is provided at the upper end of the inner cavity 111, located in front of and behind the casting cavity 113. The left and right sides of the fixing groove are connected to form a fixing through hole 114. A downward-opening fixing groove is also provided at the lower end of the inner cavity 111. Matching fixing grooves are also provided at the corresponding positions at the upper and lower ends of the outer plate 112.

[0048] The bolt assembly includes a fixing bolt and a fixing nut. During installation, after the two mold bodies 11 are assembled, the fixing bolts are passed through the fixing slots from left to right, and the fixing nuts are tightened at the ends of the fixing bolts to secure the two mold bodies 11 and complete the assembly of the mold 1.

[0049] Of course, in other embodiments, the fixing hole 114 can also be a circular through hole extending in the left-right direction.

[0050] In other embodiments, the fasteners may also be screws and nuts, with the screws passing through each fixing hole 114 in sequence and the nuts being screwed on both ends of the screws to complete the fastening.

[0051] Preferably, in this embodiment, such as Figure 1 , 4 As shown, the outer plate 112 has mounting holes 115 corresponding to the position of the sample electrode 3, such as... Figure 2 , 3 As shown, the sample electrode 3 has a threaded hole on the side facing the mounting hole 115. The sample electrode 3 is fixedly assembled to the outer plate 112 by a fixing bolt that passes through the mounting hole 115 and is screwed into the threaded hole of the sample electrode 3. This arrangement facilitates the assembly of the sample electrode 3 and the demolding of the sample after molding.

[0052] Preferably, in this embodiment, silicone rubber is applied to the gap between the two sets of mold bodies 11.

[0053] After the two sets of mold bodies 11 are assembled into mold 1 and the epoxy resin casting material is poured, silicone rubber is applied to the bottom and side seams of mold 1 to prevent the epoxy resin from slowly leaking along the gaps in the bottom and side surfaces of mold 1 in a liquid state. This reduces material waste and incomplete sample structure, while also preventing external air from entering the casting cavity 113 through the gaps and avoiding the introduction of new air bubbles.

[0054] Preferably, in this embodiment, such as Figure 1 , 4 As shown, multiple casting cavities 113 are spaced apart along the length of the mold body 11. This allows for the simultaneous preparation of multiple samples, significantly improving sample preparation efficiency.

[0055] The present invention provides a method for preparing epoxy-impregnated paper samples, using the aforementioned equipment for preparing epoxy-impregnated paper samples, specifically comprising the following steps: Step 1: Fabricate mold 1 using polytetrafluoroethylene (PTFE) material. Fabricate sample electrode 3 using aluminum metal material, and use sample electrode 3 to provide conductors for the high-voltage end and ground end of the sample.

[0056] Step 2: Preparations before sample preparation.

[0057] Wipe the surface of mold 1 with alcohol to ensure that the surface of mold 1 is clean, smooth and free of impurities, and keep mold 1 in a vacuum oven at 60℃ for about 15 minutes.

[0058] After the alcohol on the surface of mold 1 has evaporated, remove it and wipe the surface of mold 1 with a release agent. Then place it in a 110℃ vacuum oven for about 30 minutes. After removing it, wipe it a second time with the release agent and then place it in a 110℃ oven for about 12 hours.

[0059] The purpose of applying the release agent is to facilitate the smooth separation of the sample from the mold 1 after sample preparation. The purpose of high temperature treatment is to ensure that the release agent adheres effectively to the surface of the mold 1.

[0060] In other embodiments, the heat preservation time and temperature of the vacuum oven can be set according to actual needs, which will not be elaborated here.

[0061] Step 3: Material preparation.

[0062] The bisphenol A type liquid epoxy resin is placed in a vacuum oven at 50°C overnight. This step enhances the flowability of the epoxy resin, making it easier to pour out, mix, and stir later. It also prevents uneven mixing due to the high viscosity of the epoxy resin, reduces structural defects caused by insufficient stirring, and ensures the homogeneity of the sample material.

[0063] Take a clean beaker and mix the epoxy resin, curing agent methyltetrahydrophthalic anhydride, and accelerator N,N-dimethylbenzylamine in a ratio of 1:0.85:0.003. Stir the mixture in a 60℃ oil bath at 400 rpm. The oil bath is used to increase the temperature, improve the flowability of the epoxy resin, and facilitate stirring. Cover the mixture with aluminum foil during stirring to prevent reaction with air. Remove the beaker after approximately 30 minutes.

[0064] After mixing, place the mixture in a vacuum oven and evacuate it for 3-4 hours to remove air bubbles from the epoxy resin system.

[0065] Of course, in other embodiments, the ratio of epoxy resin, curing agent and accelerator can be adjusted according to the actual required mixture.

[0066] The crepe paper 2 was placed in a vacuum oven at 110℃ and dried under vacuum conditions to ensure it was completely dry. This prevents residual moisture in the crepe paper 2 from generating bubbles during the subsequent epoxy resin curing process, thus improving the equivalence between the sample and the actual core material.

[0067] Step 4: Mold assembly.

[0068] During assembly, such as Figure 3 , 4 As shown, first fix the sample electrode 3 to the outer plates 112 on both sides with bolts, then place the crepe paper 2 between the two inner cavities 111 in a taut state, so that the two mold bodies 11 tightly clamp the crepe paper 2, and then use bolt assembly to fix the two mold bodies 11 at the fixing hole 114, tighten the entire mold 1, and complete the assembly of the mold 1.

[0069] The sample electrode 3 is fixed to ensure the stability of the conductive structure. The crepe paper 2 is stretched and clamped to simulate the tensile state of the insulating paper in the actual core. The fasteners are fixed to ensure the overall stability of the mold 1. This solves the problems of improper application of external force and material state not conforming to reality in the existing sample preparation, and makes the sample structure close to the actual sleeve core.

[0070] After assembling mold 1, apply silicone rubber to the bottom and side seams of mold 1. After application, place mold 1 in a 110℃ oven for approximately 3-4 hours. This step accelerates the solidification of the silicone rubber. Once the silicone rubber has solidified, remove mold 1.

[0071] Step 5: Casting of epoxy resin casting material After removing mold 1 and allowing it to return to room temperature, take out the prepared and vacuum-treated epoxy resin casting material and slowly pour it into each casting cavity 113. Then, place mold 1 in a vacuum oven and vacuum it again at room temperature for 3-4 hours to remove air bubbles introduced during the epoxy resin casting process, ensuring stable sample performance. During this period, monitor for any epoxy resin leakage; if leakage occurs, add more resin as needed.

[0072] Step Six: Start the curing process After vacuuming is completed, if there are no abnormalities, the corresponding curing process can be started directly. The specific curing process is standard practice in this field and will not be described in detail here.

[0073] After curing is complete, remove mold 1, and first as follows: Figure 5 As shown, the outer plate 112 is removed. The sample is then removed from the inner cavity 111, resulting in the following: Figure 6 ,7 The required sample is shown.

[0074] Step 7: After obtaining the sample, conduct relevant tests according to actual testing requirements, such as withstand voltage test, partial discharge test, and electro-thermal-mechanical coupling test.

[0075] In summary, by utilizing the preparation apparatus and method of this application, the tensile state of the crepe paper 2 can be effectively controlled and the introduction of air bubbles can be reduced, thus preparing a test specimen with equivalent insulation properties to the actual epoxy impregnated paper sleeve, providing technical support for accurately evaluating the relevant performance of epoxy impregnated paper insulation materials.

[0076] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of the claims of this invention.

Claims

1. An apparatus for preparing an epoxy-impregnated paper sample, characterized by, Including mold (1), epoxy resin casting material and vacuum oven, the mold (1) includes two groups of symmetrically arranged mold bodies (11), two groups of the mold bodies (11) are fixed by fasteners; The opposite side of the mold body (11) is provided with a pouring cavity (113), the two mold bodies (11) are clamped with the tight wrinkle paper (2), the two pouring cavities (113) are symmetrically provided with sample electrodes (3), and the opposite ends of the two sample electrodes (3) are provided with pouring intervals between the wrinkle paper (2); The epoxy resin casting material is poured into the pouring cavity (113) after vacuumizing in the vacuum oven; the mold (1) with the epoxy resin casting material is treated by vacuumizing in the vacuum oven.

2. The apparatus for preparing an epoxy-impregnated paper test specimen of claim 1, wherein, The mold body (11) includes an inner cavity (111) and an outer plate body (112), the upper end of the inner cavity (111) is provided with a U-shaped opening extending from top to bottom, the U-shaped opening constitutes the pouring cavity (113), and the outer end of the sample electrode (3) is fixed with the outer plate body (112).

3. The apparatus for preparing an epoxy-impregnated paper test specimen of claim 2, wherein, The upper end and the lower end of the inner cavity (111) and the outer plate body (112) are respectively provided with a fixed perforation (114), and the fastener includes a bolt assembly penetrating in the fixed perforation (114).

4. The apparatus for preparing an epoxy-impregnated paper test specimen of claim 2, wherein, The outer plate body (112) is provided with a mounting hole (115) corresponding to the position of the sample electrode (3), and the sample electrode (3) is fixedly assembled on the outer plate body (112) by penetrating the fixing bolt in the mounting hole (115).

5. The apparatus for preparing a sample of epoxy-impregnated paper according to claim 2, wherein, The gap between the two groups of mold bodies (11) is coated with silicone rubber.

6. The apparatus for preparing a sample of epoxy-impregnated paper according to claim 1, wherein, The pouring cavities (113) are spaced apart along the length direction of the mold body (11).

7. A method for preparing an epoxy-impregnated paper test specimen for use in an apparatus according to any one of claims 1 to 6, characterized in that The method comprises the following steps: The wrinkle paper (2) is placed in the vacuum oven and dried under vacuum condition, and the prepared epoxy resin casting material is placed in the vacuum oven for vacuumizing; The sample electrodes (3) are respectively fixed in the pouring cavities (113) of the two mold bodies (11), the wrinkle paper (2) is placed in the tight state between the two mold bodies (11), the wrinkle paper (2) is clamped by the two mold bodies (11), the two mold bodies (11) are fixed by the fastener, and the mold (1) is assembled; The treated epoxy resin casting material is poured into the pouring cavity (113), and then the mold (1) is placed in the vacuum oven for vacuumizing at normal temperature; The curing process is started, and the mold (1) is taken out after curing, and the required sample is obtained by disassembling the mold (1).

8. The method for preparing an epoxy-impregnated paper test specimen according to claim 7, characterized in that, The epoxy resin casting material comprises epoxy resin, curing agent methyl tetrahydrophthalic anhydride and accelerator N,N-dimethyl benzylamine; The epoxy resin is placed in the oven at 50 DEG C for 1 day before preparation; The epoxy resin, the curing agent and the accelerator are mixed in proportion, and then stirred in the oil bath at 60 DEG C at a speed of 400 r / min; The mixed material after stirring is placed in the vacuum oven for vacuumizing, and the vacuumizing lasts for 3-4 h.

9. The method for preparing a sample of epoxy-impregnated paper according to claim 7, characterized in that, The gap between the two mold bodies (11) is coated with silicone rubber, and then placed in the oven at 110 DEG C for heat preservation, and the heat preservation lasts for 3-4 h.

10. The method for preparing a sample of epoxy-impregnated paper according to claim 7, characterized in that, The mold (1) is placed in the vacuum oven for vacuumizing at normal temperature, and the vacuumizing lasts for 3-4 h.

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