A filling resin curing process for a water-cooled transmission bus, a high-voltage large-current transmission bus and a preparation method thereof

Abstract

The present application belongs to the technical field of resin curing process and power transmission equipment, and particularly relates to a filling resin curing process for water-cooled transmission bus, a high-voltage and large-current transmission bus and a preparation method thereof. The present application firstly utilizes mixed resin with specific proportion, and performs multi-stage temperature rising curing treatment and multi-stage temperature dropping process based on autoclave forming, so as to prepare resin cured product and epoxy glass cloth composite material with good dielectric property and mechanical property. Secondly, in the process of preparing high-voltage and large-current transmission bus, the above-mentioned filling resin for water-cooled transmission bus is used for filling and epoxy glass cloth prepreg coating, and through perfecting technical details, the integrated high-voltage and large-current transmission bus is prepared, which takes into account precise bending, high-performance filling resin and high-strength insulation coating.

Description

Technical Field

[0001] This invention belongs to the technical field of resin curing process and power transmission equipment, specifically relating to a resin curing process for water-cooled transmission busbars, a high-voltage, high-current transmission busbar and its preparation method. Background Technology

[0002] Insulated busbars are a crucial component of power transmission and distribution systems, widely used in large-scale power generation, transmission, and transformation enterprises. With the rapid increase in power load, system operating currents are growing larger, loads are becoming more concentrated, and the main transformer capacity of substations is also increasing. However, previous engineering methods often used multiple rectangular busbars or direct cable connections, which are no longer adequate for high-current (above 3000A) operation, resulting in significant heat generation. In foreign countries, high-current, high-voltage insulated busbars are often manufactured using integral resin casting. Especially for high-voltage insulated busbars with curved shapes, vacuum casting is typically employed. The insulation layer of such busbars is a composite of epoxy resin and inorganic materials.

[0003] In the field of ultra-high voltage AC and DC power transmission, the transmission bus is the core component of energy transmission. It needs to withstand rated current of thousands of amperes and insulation voltage of tens of thousands of volts. High voltage and high current transmission bus will generate a lot of heat, so water channels must be designed for cooling. At the same time, the insulation layer is required to withstand high temperature, be dense without air gaps and have low partial discharge.

[0004] In current technologies, the filling resin used in high-voltage transmission buses is mostly general-purpose epoxy, which has poor matching between dielectric and mechanical properties, and is prone to curing shrinkage and interface debonding, leading to discharge between the positive and negative electrodes. In addition, it also faces technical challenges such as insulation aging and breakdown, and uneven resin filling during use.

[0005] Therefore, it is necessary to take a new approach to prepare a filled resin that has both good dielectric and mechanical properties after curing.

[0006] Secondly, we also noticed that there are many shortcomings in the manufacturing process details of high-voltage transmission buses in the existing technology:

[0007] Firstly, conductor bending often uses direct bending methods, which can easily cause deformation, collapse, and blockage in the cooling water channels. Typically, the cross-sectional deformation rate exceeds 3%, affecting heat dissipation efficiency.

[0008] Secondly, insulation coating often uses a single material or a simple composite structure, or even a conventional hand lay-up process. After curing, the internal porosity of the product is large, the partial discharge is large, and the high voltage resistance and heat aging resistance are insufficient, making it prone to insulation failure during long-term operation.

[0009] Third, the transmission bus is made of a single pole, requiring two buses for DC transmission and four buses for AC transmission, which brings a lot of work to the installation.

[0010] Therefore, developing an integrated high-voltage, high-current transmission busbar that combines precise bending, high-performance filled resin, and high-strength insulation coating, as well as its fabrication method, has become a key technological breakthrough in this field. Summary of the Invention

[0011] To address the problems identified in the prior art, this invention provides a resin-curing process for water-cooled transmission busbars, a high-voltage, high-current transmission busbar, and its preparation method. Firstly, by utilizing a specific ratio of mixed resins and employing a multi-stage heating and cooling process based on autoclave molding, a resin-cured product and an epoxy glass cloth composite material with excellent dielectric and mechanical properties are prepared. Secondly, in the process of preparing the high-voltage, high-current transmission busbar, the aforementioned resin for water-cooled transmission busbars is used for filling, followed by epoxy glass cloth prepreg coating. Through refinement of technical details, an integrated high-voltage, high-current transmission busbar that balances precise bending, high-performance resin filling, and high-strength insulation coating is prepared.

[0012] To achieve the above objectives, the present invention employs a technical solution consisting of the following technical measures.

[0013] In one aspect, the present invention provides a resin curing process for a water-cooled transmission bus, comprising the following steps:

[0014] (1) The following raw materials, by mass parts, are mixed together to form a mixture:

[0015] 38-42 parts of Hein epoxy resin

[0016] 28-32 parts of benzoxazine resin,

[0017] 28-32 parts of modified methylnadic anhydride MNA-10

[0018] 0.3-0.5 parts of curing accelerator;

[0019] (2) Place the mixture obtained in step (1) into a vacuum bag, evacuate it to a relative vacuum degree ≤ -0.090 MPa, and then place it in a thermostatic precipitator for multi-stage heating and curing treatment;

[0020] The multi-stage temperature-curing process consists of four stages. The first stage involves heating to 100°C at a rate of 1.9–2.1°C / min, and then pressurizing to 0.5 MPa at a rate of 0.04–0.06 MPa / min after reaching 80°C. Once both the temperature and pressure reach 100°C and 0.5 MPa, the pressure is maintained for 58–62 minutes. The second stage involves heating to 120°C at a rate of 1.9–2.1°C / min, and then pressurizing to 0.7 MPa at a rate of 0.04–0.06 MPa / min after reaching 110°C. This process is maintained for 118–122 minutes. Finally, the third stage involves heating to 140°C at a rate of 1.9–2.1°C / min, and then pressurizing to 130°C and 0.5 MPa. After reaching 140 ℃, the pressure is increased to 1.2 MPa at a rate of 0.04~0.06 MPa / min. When the temperature reaches 140 ℃ and the pressure reaches 1.2 MPa, the pressure is maintained for 178~182 min. After the time is up, the fourth stage of curing is carried out by increasing the temperature to 160 ℃ at a rate of 1.9~2.1 ℃ / min. When the temperature reaches 160 ℃, the pressure is maintained for 238~242 min.

[0021] (3) After multi-stage heating and curing treatment, multi-stage cooling treatment is carried out, and finally the resin cured product is taken out.

[0022] The multi-stage cooling process consists of three stages. The first stage involves cooling to 100°C at a rate of 0.9–1.1°C / min under pressure, and then holding the temperature and pressure for 118–122 minutes. After this time, the second stage involves cooling to 50°C at a rate of 0.9–1.1°C / min under pressure, and then holding the temperature and pressure for 118–122 minutes. The third stage involves cooling to room temperature at a rate of 0.9–1.1°C / min, and then depressurizing to atmospheric pressure at a rate of 0.04–0.06 MPa / min. Once room temperature and pressure are reached, the resin is removed from the autoclave, and the vacuum bag is removed to obtain the cured resin.

[0023] In this document, the hydantoin epoxy resin is a type of commercially available conventional epoxy resin containing a hydantoin ring (a five-membered dinitrogen heterocycle). Its cured products typically have excellent heat resistance, weather resistance, and high-temperature dielectric properties. Those skilled in the art can select based on the hydantoin epoxy resins commonly used in the electrical field. Preferably, the hydantoin epoxy resins suitable for use in high-voltage transmission buses are described in the prior art.

[0024] In this document, the benzoxazine resin is a type of commercially available conventional thermosetting resin containing a nitrogen- and oxygen-containing six-membered oxazine ring in its molecular structure. Its cured products typically possess properties such as heat resistance, flame retardancy, low porosity, and near-zero shrinkage. Those skilled in the art can select from benzoxazine resins conventionally used in the electrical engineering field, and preferably, benzoxazine resins suitable for application in high-voltage transmission buses are described in the prior art.

[0025] In this document, the curing accelerator is a conventional functional chemical additive used to accelerate the crosslinking reaction of polymer materials. Those skilled in the art can find suitable curing accelerators for use in combination with the hydantoin epoxy resin and benzoxazine resin specified in this invention, such as including but not limited to 2-ethyl-4-methylimidazole (CAS: 931-36-2).

[0026] In one technical solution, the mixture in step (1) may further include fillers and / or additives conventionally used in epoxy resins or mixed resins to achieve further functional expansion / process assistance / reinforcement of the cured product. The specific selection of fillers and / or additives can be referenced by those skilled in the art based on existing technology or literature, such as antioxidants, flame retardants, coupling agents, etc. It should be noted that the raw materials may include, or may not include, fillers and / or additives conventionally used in epoxy resins or mixed resins.

[0027] It should be noted that, in order to make the resin cured product obtained in step (3) have different forms, the mixture can be injected into the mold or bare busbar by filling and then placed into the vacuum bag as a whole; or the epoxy glass cloth can be impregnated with the mixture and the resulting epoxy glass cloth prepreg can be placed into the vacuum bag.

[0028] In one preferred technical solution, the multi-stage heating and curing process described in step (2) and the multi-stage cooling process described in step (3) after the multi-stage heating and curing process are carried out, wherein the vacuum bag is connected to the vacuum equipment outside the autoclave and the vacuum is continuously pumped to maintain a relative vacuum degree ≤-0.090 MPa.

[0029] One of the inventive points of this invention is that, in order to enable the cured product of the filling resin for water-cooled transmission busbars to possess the advantages of both hydantoin epoxy resin and benzoxazine resin, exhibiting good dielectric properties, heat resistance, and mechanical properties, comparative experiments were conducted to establish a mixed resin composed of hydantoin epoxy resin and benzoxazine resin in a specific ratio. Under the condition that the two resins have different suitable curing temperature windows, it was found that the synergistic multi-stage heating and curing treatment and multi-stage cooling treatment, compared with a single step of heating and cooling, resulted in a resin cured product with significantly better dielectric loss and electrical strength properties.

[0030] On the other hand, based on the practical application of the above-mentioned water-cooled transmission busbar filling resin curing process, the present invention also provides a method for preparing a high-voltage, high-current transmission busbar, which mainly includes the following steps:

[0031] (I) An initial busbar with cooling water channels is prepared by hot pressing and forming electrical conductor materials and opening holes;

[0032] (II) Fill the cooling water channel of the initial busbar obtained in step (I) with quartz sand and seal the outlets at both ends. Then bend it into shape and remove the quartz sand to obtain the shaped busbar.

[0033] (III) The surface of the molded busbar obtained in step (II) is sandblasted, and then modified epoxy adhesive is applied to the surface. After fixing, polyimide film and / or epoxy glass cloth prepreg are wrapped around it and then placed in a vacuum bag. The busbar is then subjected to multi-stage heating and curing treatment and multi-stage cooling treatment according to the above-mentioned water-cooled transmission busbar filling resin curing process. The busbar is then taken out and used as a wrapped busbar for later use.

[0034] (IV) The coated busbar obtained in step (III) is processed by the above-mentioned water-cooled transmission busbar with filling resin curing process, wherein the mixture is injected into the gap between the winding material and the formed busbar inside the coated busbar, and then put into a vacuum bag for multi-stage heating curing and multi-stage cooling treatment to prepare a bare busbar.

[0035] (V) The bare busbar obtained in step (IV) is covered with a shielding armor layer, and then treated according to the above-mentioned water-cooled transmission busbar filling resin curing process. The mixture is injected into the gap between the bare busbar and the shielding armor layer, and then put into a vacuum bag for multi-stage heating curing and multi-stage cooling treatment to prepare a high-voltage high-current transmission busbar.

[0036] In this document, the initial busbar with cooling water channels described in step (I) can refer to the specifications required for existing high-voltage transmission busbars in the art for its specific shape and size. In one technical solution, the cross-sectional shape of the initial busbar with cooling water channels includes, but is not limited to, rectangles, sectors, triangles, circles, ellipses, etc., with the short side or short radius of the cross-section ≥ 60 mm and the long side or long radius ≥ 100 mm; the cooling water channels are preferably through holes with a circular cross-section, a diameter of 20~30 mm, and 1~6 cooling water channels are provided.

[0037] In one of the technical solutions, the electrical conductor material described in step (I) is hot-pressed and has through holes. In the industrial process of this technical field, it is possible to directly purchase pre-opened semi-finished products and further prepare the initial busbar with cooling water channels of the target specifications through hot pressing.

[0038] In one preferred embodiment, when the initial busbar with cooling channels obtained in step (I) has sharp edges, the edges are further rounded with a radius of ≥2 mm to avoid charge concentration and reduce the impact on the insulation layer.

[0039] In this document, the specific shape and size of the formed busbar after bending in step (II) can refer to the specifications required for existing high-voltage transmission busbars in this field. In one technical solution, the shape of the formed busbar includes, but is not limited to, L-shaped, Ω-shaped, Z-shaped, U-shaped, etc.

[0040] One of the inventive points of this invention is that in step (II), quartz sand is filled to prevent the cooling water channel from deforming during the subsequent bending and forming process, thus solving the problem of cooling water channel deformation when bending a large cross-section busbar.

[0041] In one preferred embodiment, to reduce the deformation rate of the cooling water channel cross-section after bending, the quartz sand particle size is 20-100 mesh.

[0042] In this paper, the wrapped busbars obtained in step (III) can be further integrated and wrapped with epoxy glass cloth prepreg to finally prepare an integrated busbar. For example, when two wrapped busbars are used, the final high-voltage, high-current transmission busbar can be a two-stage busbar; when four wrapped busbars are used, the final high-voltage, high-current transmission busbar can be four integrated busbars for three-phase AC transmission.

[0043] In this paper, the winding process described in step (III) can refer to the existing high-voltage transmission bus manufacturing process, such as the constant tension winding process based on a constant tension control system.

[0044] In one technical solution, the winding of polyimide film and / or epoxy glass cloth prepreg in step (III) specifically involves first winding 1-2 layers of 0.025 mm thick polyimide film, followed by winding 0-2 layers of 2-16 mm thick epoxy glass cloth prepreg. Further, to prepare the integrated busbar, it is preferable to first wind 1-2 layers of 0.025 mm thick polyimide film around the molded busbar coated with modified epoxy adhesive, then wind 0-2 layers of 2-16 mm thick epoxy glass cloth prepreg, and after multi-stage heating and curing treatment and multi-stage cooling treatment, arrange and fix it before winding 1-2 layers of 2-16 mm thick epoxy glass cloth prepreg as a whole.

[0045] In one technical solution, it is preferable to use the polyimide film and / or epoxy glass cloth prepreg described in step (III), and after multi-stage heating and curing treatment and multi-stage cooling treatment, to perform a surface smoothing treatment on the coated busbar to reduce the porosity that may be generated in subsequent processes. Similarly, after the bare busbar is prepared in step (IV), its surface is also smoothed.

[0046] In one preferred embodiment, the epoxy glass cloth prepreg in step (III) contains a total content of hydantoin epoxy resin and benzoxazine resin of 45-55%.

[0047] In this paper, the injection method of the mixture described in steps (IV) and (V) can refer to the preparation process of high voltage transmission bus in the prior art, such as injection filling by vacuum suction, so as to minimize porosity.

[0048] In one technical solution, the injection of the mixture in steps (IV) and (V) is performed by vacuum suction, and the flow rate is controlled at 5~20 ml / min. More preferably, after the mixture is injected, the vacuum degree is maintained at ≤-0.090 MPa for at least 30 min.

[0049] In general, to ensure the product qualification rate throughout the entire preparation process, intermediate tests can be conducted on intermediate products in the preparation process of high-voltage transmission busbars, referring to the intermediate tests in the existing technology. For example, the voltage withstand test and porosity test can be conducted on the coated busbar obtained in step (III), and the voltage withstand test and porosity test can be conducted on the bare busbar obtained in step (IV).

[0050] The present invention has the following beneficial effects:

[0051] 1. This invention provides a resin curing process for water-cooled transmission busbars. By using a specific ratio of mixed resins, a multi-stage heating and curing process and a multi-stage cooling process are carried out based on autoclave molding, thereby obtaining resin cured products and epoxy glass cloth composite materials with good dielectric and mechanical properties.

[0052] 2. The present invention also provides a method for preparing a high-voltage, high-current transmission busbar. By introducing a quartz sand filling and shaping process, the cross-sectional area of ​​the busbar is reduced by ≤1% after bending, the water channel is unblocked, the inner wall is wrinkle-free, the heat dissipation efficiency is stable, and the bending forming accuracy is high.

[0053] 3. This invention combines the resin curing process for water-cooled transmission busbars with the synergistic effect of the winding insulation layer to prepare a high-voltage, high-current transmission busbar with a withstand voltage ≥65kV AC, a tracking index (PTI) ≥600, a long-term heat resistance temperature ≥155℃, and a service life ≥20 years. More advantageously, the entire production process utilizes vacuum technology and autoclave molding technology in multiple places, resulting in the following beneficial outcomes: a dense insulation layer without bubbles or cracks, and partial discharge of the insulation layer ≤50PC@26KVAC.

[0054] 4. By utilizing the water-cooled transmission busbar with a resin-filled curing process, the cured product exhibits excellent dielectric and mechanical properties, strong adhesion to conductors and insulation layers, and no cracking or peeling. Attached Figure Description

[0055] Figure 1 The bar chart shows the comparison of the dielectric loss performance of the cured products prepared in Example 1 and Comparative Examples 1-11 of this invention.

[0056] Figure 2 This is a bar chart comparing the electrical strength properties of the cured products prepared in Example 1 and Comparative Examples 1-11 of the present invention.

[0057] Figure 3 This is a schematic diagram of the overall preparation method process of Embodiment 2 of the present invention.

[0058] Figure 4 This is a schematic diagram of the disassembled structure of the two-pole bare busbar prepared in Example 2 of the present invention.

[0059] Figure 5 This is a schematic diagram of the cross-sectional structure of the high-voltage, high-current transmission bus prepared in Embodiment 3 of the present invention.

[0060] Figure 6 This is a photograph of the autoclave used in Embodiment 1 of the present invention.

[0061] In the diagram, 1 is the molding busbar, 2 is the polyimide film layer, 3 is the epoxy glass cloth prepreg layer, 4 is the cooling water channel, and 5 is the shielding armor layer. Detailed Implementation

[0062] The embodiments of this application will be described in detail below with reference to examples. However, those skilled in the art will understand that the following examples are for illustrative purposes only and should not be construed as limiting the scope of this application. Where specific conditions are not specified in the examples, conventional conditions or conditions recommended by the manufacturer shall apply. Where the manufacturers of reagents or instruments are not specified, they are all commercially available conventional products. This application should not be construed as being limited to the specific embodiments described.

[0063] Example 1

[0064] This embodiment describes a resin curing process for a water-cooled transmission bus, including the following steps:

[0065] (1) The following raw materials, by mass parts, are mixed together to form a mixture:

[0066] 40 parts of Hain epoxy resin MHR-070 (Hubei Longxin Chemical Co., Ltd.)

[0067] 30 parts of benzoxazine resin CB2900 (Chengdu Keyi Polymer Technology Co., Ltd.)

[0068] Modified methyl nadic anhydride MNA-10 (Jingjiang Yongtaifeng Chemical Co., Ltd.) 30 parts

[0069] 0.4 parts of 2-ethyl-4-methylimidazole;

[0070] (2) Place the mixture obtained in step (1) into a vacuum bag, evacuate it to a relative vacuum degree ≤ -0.090 MPa, and then place it in an autoclave (DN1500×4000, Zhucheng Antai Machinery Co., Ltd., such as...). Figure 6 (As shown) undergoes multi-stage heating and curing treatment;

[0071] The multi-stage temperature-curing process consists of four stages, as shown in Table 1 below:

[0072] Table 1: Parameters of the Four-Stage Temperature-Increasing Curing Process

[0073]

[0074] (3) After multi-stage heating and curing treatment, multi-stage cooling treatment is carried out, and finally the resin cured product is taken out as a sample.

[0075] The multi-stage cooling process consists of three stages, as shown in Table 2 below:

[0076] Table 2: Three-stage cooling process parameters

[0077]

[0078] Comparative Examples 1-11

[0079] Comparative Examples 1 to 11 are comparative experiments based on the process of Example 1. The variables are multi-stage heating curing treatment, multi-stage cooling treatment, and whether the relative vacuum degree is maintained at ≤-0.090 MPa during the above treatments. Resin cured products were prepared as comparative samples.

[0080] The cured resin obtained in Example 1 was designated as serial number 1, and the cured resins obtained in Comparative Examples 1 to 11 were designated as serial numbers 2 to 12, respectively. The dielectric loss (%) and electrical strength (MV / mm) of the cured resins obtained in Example 1 and Comparative Examples 1 to 11 were tested according to national standards GB / T1409-2006 and GB / T1408.1-2016, respectively. Specific variable parameters and test results are shown in Table 3 below. Figure 1 , Figure 2 As shown:

[0081] Table 3: Summary of process variable parameters and test results for serial numbers 1-12

[0082]

[0083] In the table, "-" indicates that the heating / curing or cooling treatment is not performed in that stage. For example, in item 11 (Comparative Example 10), the heating / curing process involves heating to 100°C at a rate of 2°C / min, and then pressurizing to 0.5 MPa at a rate of 0.05 MPa / min after reaching 80°C. Once the temperature reaches 100°C and the pressure reaches 0.5 MPa, the temperature and pressure are maintained for 180 min. After this time, the temperature is increased to 160°C at a rate of 2°C / min, and then pressurized to 1.2 MPa at a rate of 0.05 MPa / min after reaching 130°C. Once the temperature and pressure reach 160°C and 1.2 MPa, the temperature and pressure are maintained for 420 min. The cooling process involves cooling to 50°C at a rate of 1°C / min under pressure. Once the temperature reaches 50°C, the temperature and pressure are maintained for 240 min. After the set time is reached, cool down to room temperature at a rate of 1 °C / min, and then depressurize to atmospheric pressure at a rate of 0.05 MPa / min. Once room temperature and atmospheric pressure are reached, remove the product from the autoclave and remove the vacuum bag to obtain the cured resin. The other comparative examples should be performed in the same manner.

[0084] In the table, vacuum level is indicated by "-" to mean that the external vacuum equipment of the autoclave is not turned on, and the relative vacuum level is not maintained at ≤-0.090 MPa. For example, in serial number 4 (Comparative Example 3), the relative vacuum level is maintained at ≤-0.090 MPa throughout the heating and curing process, but during the cooling process, the vacuum equipment is turned off, and the relative vacuum level is not maintained at ≤-0.090 MPa. The other comparative examples are performed in the same manner.

[0085] Example 2

[0086] Example 2 provides a method for preparing a high-voltage, high-current transmission bus, which mainly includes the following steps:

[0087] (I) Select 6063 aluminum alloy ingots with a purity ≥99.7%, place them in a homogenizing furnace and keep them at 480 ℃ for 8 hours, then send them into a 2000-ton CNC extrusion press. Preheat the die to 380 ℃ and extrude a 200 mm × 100 mm rectangle at a speed of 1 m / min. After opening holes, stretching and straightening, cutting and rounding, the initial busbar with cooling water channels is prepared.

[0088] (II) Fill the cooling water channels of the initial busbar obtained in step (I) with 50-mesh quartz sand, tamp it down, and seal both ends with bolts. After preheating to 180 ℃, place it into a special arc bending die of a 3600T hydraulic press and bend it at a pressure speed of 0.8 mm / s with a bending radius of 220 mm. Remove the quartz sand with 0.8 MPa high-pressure air. The cross-sectional area of ​​the cooling water channel is reduced by no more than 0.8% by a laser 3D scanner. The roundness tolerance of the cooling water channel is 0.1 mm and it is unobstructed. The formed busbar is then obtained.

[0089] The reduction ratio of the cross-sectional area of ​​the cooling water channel is calculated as (1 - cross-sectional area of ​​the cooling water channel after bending ÷ cross-sectional area of ​​the cooling water channel before bending) × 100%;

[0090] (III) The surface of the molded busbar obtained in step (II) is sandblasted to control the roughness Ra=1.4 μm. Then, a modified epoxy adhesive is applied to the surface and fixed. After fixing, two layers of 0.025 mm thick polyimide film are wound using a constant tension winding machine with a tension of 1.5 N / cm. Then, epoxy glass cloth prepreg (resin content 50%) is wound to a thickness of 6 mm. During winding, far-infrared heating is maintained at 90 ℃ with a tension of 4 N / cm.

[0091] The tubes are placed in a vacuum bag and subjected to multi-stage heating and curing treatment and multi-stage cooling treatment according to Example 1 above. The tubes are then removed and used as the coated busbars.

[0092] Then, the surface of the wrapped busbar is smoothed. After passing the voltage withstand test and porosity test, the two wrapped busbars are fixed and positioned, and then the whole is wrapped with epoxy glass cloth prepreg to a thickness of 6 mm to serve as the two-pole wrapped busbars.

[0093] (IV) The bipolar coated busbar obtained in step (III) is processed according to Example 1, wherein the mixture is injected into the gap between the winding material and the formed busbar in the bipolar coated busbar by vacuum suction, and then put into a vacuum bag for multi-stage heating and curing treatment and multi-stage cooling treatment to prepare the bipolar bare busbar.

[0094] (V) After the two bare busbars obtained in step (IV) pass the surface smoothing treatment, voltage withstand test and porosity test, they are covered with a 1 mm thick shielding armor layer (SU304). Then they are processed according to Example 1, wherein the mixture is injected into the gap between the two bare busbars and the shielding armor layer by vacuum suction. Then they are put into a vacuum bag for multi-stage heating and curing treatment and multi-stage cooling treatment to prepare a high voltage and high current transmission busbar with two busbars.

[0095] like Figure 3 The diagram shows a schematic representation of the overall preparation method process in Example 2.

[0096] like Figure 4 The diagram shows a disassembled structure of the bare busbars prepared in Example 2. In the diagram, the molded busbar 1 is wrapped with a polyimide film layer 2 and an epoxy glass cloth prepreg layer 3. Then, the two wrapped busbars are wrapped with the epoxy glass cloth prepreg layer 3 as a whole.

[0097] Comparative Example 12

[0098] Comparative Example 12 is based on the preparation method of Example 2, but in step (II), quartz sand was not filled in the cooling water channel and the bending was performed directly. The maximum reduction in the cross-sectional area of ​​the cooling water channel was 12%, as detected by a laser three-dimensional scanner.

[0099] Example 3

[0100] Example 3 is based on the preparation method of Example 2, and a high-voltage, high-current transmission busbar with integrated four busbars for three-phase AC transmission is prepared. The difference from Example 2 is that after fixing in step (III), two layers of 0.025mm thick polyimide film are wound using a constant tension winding machine with a tension of 1.5 N / cm; then, after fixing and positioning the two busbars wound with polyimide film, epoxy glass cloth prepreg is wound around the whole body to a thickness of 6 mm, and then placed in a vacuum bag for multi-stage heating and curing treatment and multi-stage cooling treatment according to Example 1 above. The busbar is then taken out as the two-pole busbar after coating.

[0101] Then, the surfaces of the two coated busbars are smoothed. After passing the voltage withstand test and porosity test, the two coated busbars are fixed in position and then wrapped with epoxy glass cloth prepreg to a thickness of 6 mm to form an integrated coated busbar.

[0102] like Figure 5 As shown, a schematic diagram of the cross-sectional structure of the high-voltage, high-current transmission busbar prepared in this embodiment 3 is presented. In the figure, the molded busbar 1 has multiple cooling water channels 4, and two adjacent left and right molded busbars 1 are wrapped with a polyimide film layer and an epoxy glass cloth prepreg layer 3. All four molded busbars 1 are wrapped with an epoxy glass cloth prepreg layer 3 and a shielding armor layer 5.

[0103] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A process for curing a filled resin for water-cooled transmission busbars, characterized in that Comprising the following steps: (1) The raw materials including the following components are mixed by mass fraction to obtain a mixture: Hyein epoxy resin 38~42 parts, Benzoxazine resin 28~32 parts, Modified methyl nadic anhydride MNA-10 28~32 parts, Curing accelerator 0.3~0.5 parts; (2) The mixture obtained in step (1) is placed in a vacuum bag, vacuumed to a relative vacuum degree of ≤-0.090 MPa, and then placed in a hot press tank for multi-stage temperature rising curing treatment; The multi-stage temperature rising curing treatment is four-stage temperature rising curing, the first stage temperature rising curing is to rise to 100 ℃ at a temperature rising speed of 1.9~2.1 ℃ / min, and to pressurize to 0.5 MPa at a pressure rising speed of 0.04~0.06 MPa / min after the temperature reaches 80 ℃, when the temperature reaches 100 ℃ and the pressure reaches 0.5 MPa, the temperature and pressure are maintained for 58~62 min; after the time reaches, the second stage temperature rising curing is to rise to 120 ℃ at a temperature rising speed of 1.9~2.1 ℃ / min, and to pressurize to 0.7 MPa at a pressure rising speed of 0.04~0.06 MPa / min after the temperature reaches 110 ℃, when the temperature reaches 120 ℃ and the pressure reaches 0.7 MPa, the temperature and pressure are maintained for 118~122 min; after the time reaches, the third stage temperature rising curing is to rise to 140 ℃ at a temperature rising speed of 1.9~2.1 ℃ / min, and to pressurize to 1.2 MPa at a pressure rising speed of 0.04~0.06 MPa / min after the temperature reaches 130 ℃, when the temperature reaches 140 ℃ and the pressure reaches 1.2 MPa, the temperature and pressure are maintained for 178~182 min; after the time reaches, the fourth stage temperature rising curing is to rise to 160 ℃ at a temperature rising speed of 1.9~2.1 ℃ / min, and when the temperature reaches 160 ℃, the temperature and pressure are maintained for 238~242 min; (3) After the multi-stage temperature rising curing treatment, multi-stage temperature dropping treatment is carried out, and the resin cured product is obtained by finally taking out; The multi-stage temperature dropping treatment is three-stage temperature dropping, the first stage temperature dropping is to drop to 100 ℃ at a temperature dropping speed of 0.9~1.1 ℃ / min under pressure maintaining condition, when the temperature reaches 100 ℃, the temperature and pressure are maintained for 118~122 min; after the time reaches, the second stage temperature dropping is to drop to 50 ℃ at a temperature dropping speed of 0.9~1.1 ℃ / min under pressure maintaining condition, when the temperature reaches 50 ℃, the temperature and pressure are maintained for 118~122 min; the third stage temperature dropping is to drop to room temperature at a temperature dropping speed of 0.9~1.1 ℃ / min, and to drop to normal pressure at a pressure dropping speed of 0.04~0.06 MPa / min, and the resin cured product is obtained by taking out from the hot press tank after reaching room temperature and normal pressure, and removing the vacuum bag.

2. The process for curing the filled resin for water-cooled transmission bus bars according to claim 1, characterized by: The curing accelerator includes 2-ethyl-4-methylimidazole.

3. The process for curing the filled resin for water-cooled transmission bus bars according to claim 1, characterized by: The multi-stage temperature rising curing treatment in the hot press tank in step (2) and the multi-stage temperature rising curing treatment followed by multi-stage temperature dropping treatment in step (3) are performed with the vacuum bag being in communication with the vacuum device outside the hot press tank and continuously being vacuumized to keep the relative vacuum degree less than or equal to -0.090 MPa.

4. A method of making a high voltage, high current transmission bus, characterized by The method comprises the following steps: (I) selecting an electrical conductor material, hot-pressing, and opening a hole to prepare an initial busbar with a cooling water channel; (II) filling quartz sand in the cooling water channel of the initial busbar obtained in step (I) and sealing the two end outlets, then bending and forming, and removing the quartz sand to obtain a formed busbar; (III) sandblasting the surface of the formed busbar obtained in step (II), then brushing a modified epoxy adhesive on the surface, fixing, winding polyimide film and epoxy glass cloth prepreg, the epoxy glass cloth prepreg being obtained by impregnating epoxy glass cloth in the mixture in claim 1, and then performing multi-stage temperature rising curing treatment and multi-stage temperature dropping treatment according to the resin filling and curing process for water-cooled transmission busbars in claim 1, and taking out the coated busbar for standby use; (IV) performing treatment on the coated busbar obtained in step (III) according to the resin filling and curing process for water-cooled transmission busbars in claim 1, wherein the mixture is injected into the gap between the winding material and the formed busbar in the coated busbar, and then the vacuum bag is filled to perform multi-stage temperature rising curing treatment and multi-stage temperature dropping treatment, to obtain a bare busbar; (V) coating a shielding armor layer on the bare busbar obtained in step (IV), and then performing treatment according to the resin filling and curing process for water-cooled transmission busbars in claim 1, wherein the mixture is injected into the gap between the bare busbar and the shielding armor layer, and then the vacuum bag is filled to perform multi-stage temperature rising curing treatment and multi-stage temperature dropping treatment, to obtain a high-voltage and large-current transmission busbar.

5. The method of claim 4, wherein: Step (I) further comprises rounding the edges of the initial busbar, and the rounding radius is greater than or equal to 2 mm.

6. The method of claim 4, wherein: In step (II), the particle size of the quartz sand is 20-100 mesh.

7. The method of claim 4, wherein: In step (III), the coated busbar obtained is integrated and integrally wound with epoxy glass cloth prepreg.

8. The method of claim 4, wherein: In step (III), the winding of the polyimide film and the epoxy glass cloth prepreg is specifically winding 1-2 layers of 0.025 mm thick polyimide film, and then winding 0-2 layers of 2-16 mm thick epoxy glass cloth prepreg.

9. The method of claim 4, wherein: In step (III), the epoxy glass cloth prepreg, wherein the total content of the hydantoin epoxy resin and the benzoxazine resin is 45-55%.

10. The method of claim 4, wherein: In steps (IV) and (V), the injection of the mixture is performed by vacuum suction, and the flow rate is controlled to be 5-20 ml / min.

11. The high-voltage and large-current transmission busbar prepared by the method in claim 4.

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