Method for preparing shielding net

Abstract

The present application discloses a method for preparing a shielding net, which comprises taking bisphenol A epoxy resin as a casting base material, adding a curing agent and a filler, injecting the casting material into an APG mold, and sequentially subjecting the casting material to a heating molding process, a curing process, and a zinc spraying process. The prepared shielding net has excellent insulation performance and greatly improves the shielding effect of the shielding net. The zinc layer is adapted to the shape of the shielding net module and can completely cover the surface of the shielding net module. The prepared shielding net has good shape and size controllability, and the deformation of the shielding net is small, which can meet the use size and shape requirements of solid insulation ring network cabinet components. The shielding net is cast into a solid insulation part, and then the solid insulation part is installed in the solid insulation cabinet, which solves the problem of poor insulation and reliability of the solid insulation ring network cabinet caused by shrinkage of the shielding net and poor insulation, and can ensure the long-term safe and stable operation of the solid insulation ring network cabinet.

Description

Technical Field

[0001] The present application relates to the field of electric power technology, and in particular to a method for preparing a shielding net. Background Art

[0002] A solid-insulated ring main unit (RMU) is a RMU that uses solid insulating material as the main insulating medium. The vacuum interrupter and its conductive connections, isolating and grounding switches, main busbars, branch busbars and other components are all covered and sealed with solid insulating media to form an insulating structure with full insulation and full sealing performance. At the same time, a conductive or semi-conductive shielding layer is coated on the surface of the structure that can be touched by humans, and the insulating structure is directly and reliably grounded. The solid-insulated RMU is an electrical equipment that is enclosed in a grounded metal casing after all components are assembled, and its insulating outer surface is also grounded through the box.

[0003] The shielding mesh is a core component of the solid-state insulated ring main unit (RMU). It can improve the insulation performance and reliability of the solid-state insulated components and ensure the long-term safe and stable operation of the solid-state insulated cabinet. However, in the prior art, regular mesh rings are usually made of metal materials; irregular shielding meshes are generally made of semi-conductive nylon through an injection molding process. During the heating injection molding process, the semi-conductive nylon deforms significantly when the temperature changes. Especially when preparing shielding meshes larger than 100 mm, the semi-conductive nylon material is easily deformed during the heating injection molding process. Therefore, the irregular shielding meshes prepared by semi-conductive nylon injection molding are difficult to control in terms of external dimensions, resulting in a low shielding mesh qualification rate and high production costs. The resulting shielding mesh cannot meet the size and shape requirements of the solid-state insulated cabinet components. At the same time, the shielding meshes made of semi-conductive nylon materials have poor insulation and reliability, making it difficult to ensure the long-term safe and stable operation of the solid-state insulated cabinet. Summary of the Invention

[0004] In order to solve the problem in the prior art that the shielding net is extremely easy to deform during the heating injection molding process, the deformation of the prepared shielding net is large, and its shape and size are difficult to control, and it cannot meet the size and shape requirements of the solid insulation ring network cabinet components. At the same time, the insulation and reliability of the shielding net are poor, and it is difficult to solve the problem of long-term safe and stable operation of the solid insulation ring network cabinet. The present invention uses bisphenol A epoxy resin as a casting base material to prepare a shielding net module through an APG injection molding process, and then sprays zinc on the shielding net module with a zinc layer thickness of 10μm-15μm to prepare a shielding net, which greatly improves the insulation and reliability of the shielding net. At the same time, the size and shape of the prepared shielding net are controllable, which can meet the size and shape requirements of the solid insulation ring network cabinet components, and at the same time reduces the production cost.

[0005] The present invention discloses a method for preparing a shielding net, comprising the following steps:

[0006] (1) Prepare an APG mold with the same size as the shielding mesh;

[0007] (2) injecting the casting material into the APG mold, heating and molding the casting material, heating and curing the casting material in sequence, and then demolding and cooling to room temperature to obtain a shielding mesh module for standby use;

[0008] (3) Use a sandblasting machine to blast the shielding mesh module with steel grit, the steel grit size is 20-30 mesh, and then use ethanol to clean the shielding mesh module after the steel grit blasting;

[0009] (4) The cleaned shielding mesh module is subjected to a heat treatment, and then subjected to a zinc spraying treatment to prepare a shielding mesh.

[0010] In one embodiment of the present invention, the casting material comprises bisphenol A epoxy resin, a curing agent, and a filler; the mass ratio of the bisphenol A epoxy resin, the curing agent, and the filler is 1:1:3-5;

[0011] In one embodiment of the present invention, the bisphenol A epoxy resin includes one of E-44 epoxy resin, E-51 epoxy resin, E54 epoxy resin, and E55 epoxy resin;

[0012] In one embodiment of the present invention, the curing agent includes one of phthalic anhydride, trimellitic anhydride, and methyltetrahydrophthalic anhydride;

[0013] The filler comprises one of nano-silicon dioxide and nano-titanium dioxide, and the particle size of the nano-silicon dioxide and nano-titanium dioxide is 30nm-1μm;

[0014] In one embodiment of the present invention, the heating and forming treatment temperature in step (2) is 145-155°C;

[0015] In one embodiment of the present invention, the heating and curing treatment temperature and time in step (2) are 110-130°C / 12-17h;

[0016] In one embodiment of the present invention, the temperature and time for heating the cleaned shielding mesh module in step (4) are 70-75°C / 2-2.5h;

[0017] In one embodiment of the present invention, the shielding mesh module is subjected to zinc spraying treatment in step (4), and the zinc layer thickness is 10 μm-15 μm; the zinc spraying treatment temperature is 70-75° C.;

[0018] In one embodiment of the present invention, the shielding mesh module is subjected to zinc spraying treatment in step (4), and the resistance between meshes of the prepared shielding mesh is 5-20Ω;

[0019] In summary, in the process of heat forming, the shielding net obtained by using semi-conductive nylon as the casting base material after heat forming treatment has a large deformation and poor insulation. When the shielding net is cast in the solid insulation ring network cabinet, the shielding net will shrink, resulting in an increase in the local discharge value of the solid insulation part and poor insulation. The solid insulation part with poor insulation is then installed in the solid insulation cabinet, and the insulation and reliability of the solid insulation cabinet are reduced, making it difficult to ensure the long-term safe and stable operation of the solid insulation ring network cabinet. The present invention uses bisphenol A epoxy resin as the casting base material, and through the APG injection molding process, after the heat forming process, the deformation of the shielding net obtained is extremely small, and the shielding net obtained after the heat forming process is The shielding mesh module is zinc-sprayed, and the thickness of the zinc layer is controlled to be 10μm-15μm. After heat forming treatment, the resistance between the mesh holes of the prepared shielding mesh is 5-20Ω, which greatly improves the shielding effect of the shielding mesh, and the shielding mesh has good insulation properties; the zinc layer is adapted to the shape of the shielding mesh module and can completely cover the surface of the shielding mesh module, so that the deformation of the prepared shielding mesh is small, and pouring the prepared shielding mesh into the solid insulation part can avoid the problem of excessive local discharge value of the solid insulation part due to the shrinkage of the shielding mesh, which in turn affects the insulation and reliability of the solid cabinet, and the shape and size of the shielding mesh are well controllable, which can meet the use size and shape requirements of the solid insulation ring network cabinet components.

[0020] At the same time, the shielding net of the present application uses epoxy resin as the casting base material, and the shielding net produced is not easy to shrink when cast in the solid insulating part. Casting the shielding net into the solid insulating part solves the problem of excessive local discharge value of the solid insulating part due to shrinkage of the shielding net. Then, installing the solid insulating part in the solid insulating cabinet can solve the problem of poor insulation and reliability of the solid insulating ring network cabinet. The shielding net produced by the present application can ensure the long-term safe and stable operation of the solid insulating cabinet. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the technical solution of the present invention, the following briefly introduces the drawings required for use in the embodiments. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0022] Figure 1 The present invention adopts the APG process to prepare the structural diagram of the solid insulation component for the solid insulation ring network cabinet;

[0023] Figure 2 This is a structural diagram of the shielding mesh prepared in Example 2 of the present invention being poured into a solid insulating member;

[0024] Figure 3 This is a structural diagram of the shielding net obtained in Example 2 of the present invention;

[0025] Figure 4This is a structural diagram of the shielding net prepared in comparative example 2 of the present invention. DETAILED DESCRIPTION

[0026] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below in conjunction with specific implementation methods.

[0027] Example 1

[0028] (1) Prepare an APG mold with the same size as the shielding mesh;

[0029] (2) injecting the castable into the APG mold, heating and molding the castable at 145°C, and then performing a heat curing treatment at a temperature and time of 110°C / 12h; then demolding and cooling to room temperature to obtain a shielding mesh module for standby use;

[0030] (3) Using a sandblasting machine to blast the shielding mesh module with steel grit, the steel grit size is 20 mesh, and then using 95% ethanol to clean the shielding mesh module after the steel grit blasting;

[0031] (4) The shielding mesh module after cleaning is subjected to heat treatment at a temperature and time of 70°C / 2h. Subsequently, the shielding mesh module is subjected to zinc spraying treatment at a temperature of 70°C. The thickness of the zinc layer is 10μm. A shielding mesh is prepared. The resistance between the mesh holes of the shielding mesh is tested with a multimeter and is 5Ω.

[0032] The casting material consists of E-51 epoxy resin, phthalic anhydride and nano-silicon dioxide, wherein the mass ratio of the E-51 epoxy resin, phthalic anhydride and nano-silicon dioxide is 1:1:3.5; and the particle size of the nano-silicon dioxide is 30nm-1μm.

[0033] Example 2

[0034] (1) Prepare an APG mold with the same size as the shielding mesh;

[0035] (2) injecting the castable into the APG mold, heating and molding the castable at 150°C, and then performing a heat curing treatment at a temperature and time of 120°C / 14h; then demolding and cooling to room temperature to obtain a shielding mesh module for standby use;

[0036] (3) Using a sandblasting machine to blast the shielding mesh module with steel grit, the steel grit size is 25 mesh, and then using 95% ethanol to clean the shielding mesh module after the steel grit blasting;

[0037] (4) The cleaned shielding mesh module is subjected to a heat treatment at a temperature and time of 72°C / 2.2h. Subsequently, the shielding mesh module is subjected to a zinc spraying treatment at a temperature of 72°C. The thickness of the zinc layer is 13μm. A shielding mesh is prepared. The resistance between the mesh holes of the shielding mesh is tested with a multimeter and is found to be 10Ω.

[0038] The casting material consists of E-44 epoxy resin, methyltetrahydrophthalic anhydride and nano-silicon dioxide. The mass ratio of the E-51 epoxy resin, methyltetrahydrophthalic anhydride and nano-silicon dioxide is 1:1:4. The particle size of the nano-silicon dioxide is 30nm-1μm.

[0039] Example 3

[0040] (1) Prepare an APG mold with the same size as the shielding mesh;

[0041] (2) injecting the castable into the APG mold, heating and molding the castable at 155°C, and then performing a heat curing treatment at a temperature and time of 130°C / 17h; then demolding and cooling to room temperature to obtain a shielding mesh module for standby use;

[0042] (3) Using a sandblasting machine to blast the shielding mesh module with steel grit, the steel grit size is 30 mesh, and then using 95% ethanol to clean the shielding mesh module after the steel grit blasting;

[0043] (4) The cleaned shielding mesh module is subjected to a heat treatment at a temperature and time of 75°C / 2.5h. Subsequently, the shielding mesh module is subjected to a zinc spraying treatment at a temperature of 75°C. The thickness of the zinc layer is 15μm. A shielding mesh is prepared. The resistance between the mesh holes of the shielding mesh is tested with a multimeter and is found to be 20Ω.

[0044] The casting material consists of E-54 epoxy resin, trimellitic anhydride and nano-silicon dioxide, wherein the mass ratio of the E-54 epoxy resin, trimellitic anhydride glyceride and nano-titanium dioxide is 1:1:4.5; and the particle size of the nano-silicon dioxide is 30nm-1μm.

[0045] Comparative Example 1

[0046] The specific implementation is the same as that of the first embodiment except that the casting material is semi-conductive nylon.

[0047] Comparative Example 2

[0048] The specific implementation is the same as the second embodiment except that the casting material is semi-conductive nylon.

[0049] Comparative Example 3

[0050] The specific implementation is the same as that of the third embodiment except that the casting material is semi-conductive nylon.

[0051] Performance testing:

[0052] like Figure 1 Using the common APG casting process (casting material is injected into the APG mold, heated and solidified, and then cooled to room temperature after demoulding), five identical solid insulation parts for solid insulation ring network cabinets are prepared, such as Figure 2 As shown, the shielding mesh prepared in Example 2 is cast into the first solid insulating part for a solid insulating ring network cabinet, and the casting material is epoxy resin, to prepare a solid insulating part with a shielding mesh. The shielding mesh prepared in Example 1, Comparative Example 1, Comparative Example 2, and Comparative Example 3 are cast in the same way as in Example 2, and are respectively cast into the second to fifth solid insulating parts for a solid insulating ring network cabinet to prepare a solid insulating part with a shielding mesh.

[0053] A power frequency withstand voltage tester was used, and an oscilloscope was turned on. The power frequency withstand voltage tester was purchased from Shanghai Songbao Electric, and the partial discharge values ​​of the solid insulation components with shielding mesh in Examples 1 to 3 and Comparative Examples 1 to 3 were tested. The test results are shown in Table 1:

[0054] Table 1: Partial discharge values ​​of solid insulation parts cast with shielding mesh in Examples 1 to 3 and Comparative Examples 1 to 3

[0055]

[0056] By comparing the performance test results of the embodiments and comparative examples, it can be seen that the present application uses bisphenol A epoxy resin as a casting material, and through the APG injection molding process, a heating molding process, and zinc spraying treatment, the thickness of the zinc layer is controlled to be 10μm-15μm, and the resistance between the meshes of the zinc layer is controlled to be 5-20Ω, which greatly improves the shielding effect of the shielding net. The shielding net has good insulation properties. The shielding net is poured into a solid insulation part for a solid insulation ring network cabinet to prepare a solid insulation part with a shielding net. The local discharge value of the solid insulation part with a shielding net can be as low as 1pc. It can be seen from the test standard that when the local discharge is ≤5PC, the insulation of the insulation part is qualified. Compared with the local discharge value of the solid insulation part with a shielding net made of traditional semi-conductive nylon, the local discharge value of the solid insulation part with a shielding net prepared by the present application is greatly reduced, which shows that the shielding net prepared by the present application has excellent insulation properties.

[0057] When the shielding net produced by the present application is poured into a solid insulating part, the solid insulating part has good insulation properties. When the solid insulating part is then installed in a solid insulating cabinet, the problem of poor insulation and reliability of the solid insulating cabinet caused by excessive local discharge values ​​of the shielding net and poor insulation can be effectively solved. At the same time, the shielding net of the present application uses epoxy resin as a casting base material, and the shielding net produced is not easy to shrink when cast in the solid insulating part, which effectively solves the problem of increased local discharge values ​​of the solid insulating part caused by shrinkage of the shielding net, thereby affecting the insulation and reliability of the solid cabinet. The shielding net produced by the present application can ensure the long-term safe and stable operation of the solid insulating cabinet.

[0058] By comparing the shielding net prepared in Example 2 of the present invention (see Figure 3 ) and the shielding net obtained in comparative example 2 of the present invention (see Figure 4 ) As can be seen from the structural diagram, Example 2 of the present invention uses bisphenol A epoxy resin as a casting base material, and the shielding mesh obtained by the APG injection molding process has a very small deformation. The shape and size of the prepared shielding mesh are well controllable and can meet the use size and shape requirements of the solid insulation cabinet components. The shielding mesh is poured into the solid insulation part, and then the solid insulation part is installed in the solid insulation cabinet, which can solve the problem of the increase in the partial discharge value of the solid insulation cabinet due to the shrinkage of the shielding mesh. However, Comparative Example 2 uses semi-conductive nylon as a casting base material. After the heat molding process, the shielding mesh obtained has a large deformation, and the two sides of the shielding mesh are greatly bent toward the central axis of the component. The shielding mesh is poured into the solid insulation part, and then the solid insulation part is installed in the solid insulation cabinet. The shielding mesh will shrink, which will lead to an increase in the partial discharge value of the solid insulation cabinet, greatly reducing the insulation and reliability of the solid insulation cabinet, making it difficult to ensure the long-term safe and stable operation of the insulation cabinet.

[0059] The present application has been described in detail above with reference to specific embodiments and exemplary examples. However, these descriptions should not be construed as limiting the present application. Those skilled in the art will appreciate that, without departing from the spirit and scope of the present application, various equivalent substitutions, modifications, or improvements may be made to the technical solutions and implementations of the present application, all of which fall within the scope of the present application. The scope of protection of the present application shall be determined by the appended claims.

Claims

1. A method for preparing a shielding net, characterized in that: The following steps are involved: (1) Prepare an APG mold with the same size as the shielding mesh; (2) injecting the casting material into the APG mold, heating and molding the casting material, heating and curing the casting material in sequence, and then demolding and cooling to room temperature to obtain a shielding mesh module for standby use; (3) Use a sandblasting machine to blast the shielding mesh module with steel grit, the steel grit size is 20-30 mesh, and then use ethanol to clean the shielding mesh module after the steel grit blasting; (4) The cleaned shielding mesh module is subjected to a heat treatment, and then subjected to a zinc spraying treatment to prepare a shielding mesh; wherein the resistance between meshes of the prepared shielding mesh is 5-20Ω.

2. The method for preparing a shielding net according to claim 1, characterized in that: The casting material comprises bisphenol A epoxy resin, a curing agent and a filler; the mass ratio of the bisphenol A epoxy resin, the curing agent and the filler is 1:1:3-5.

3. The method for preparing a shielding net according to claim 2, wherein: The bisphenol A epoxy resin includes one of E-44 epoxy resin, E-51 epoxy resin, E54 epoxy resin and E55 epoxy resin.

4. The method for preparing a shielding net according to claim 3, characterized in that: The curing agent includes one of phthalic anhydride, trimellitic anhydride and methyltetrahydrophthalic anhydride.

5. The method for preparing a shielding net according to claim 4, characterized in that: The filler comprises one of nano silicon dioxide and nano titanium dioxide, and the particle size of the nano silicon dioxide and nano titanium dioxide is 30nm-1μm.

6. The method for preparing a shielding net according to claim 1, wherein: The heating and forming treatment temperature in step (2) is 145-155°C.

7. The method for preparing a shielding net according to claim 1, wherein: The heating and curing treatment temperature and time in step (2) are 110-130°C / 12-17h.

8. The method for preparing a shielding net according to claim 1, wherein: In the step (4), the temperature and time for heating the cleaned shielding mesh module are 70-75°C / 2-2.5h.

9. The method for preparing a shielding net according to claim 1, wherein: In the step (4), the shielding mesh module is subjected to zinc spraying treatment, and the thickness of the zinc layer is 10 μm-15 μm.

Images