Composite post insulator winding pipe and preparation method

Abstract

The invention relates to the technical field of winding pipes, in particular to a composite post insulator winding pipe and a preparation method. The composite post insulator winding pipe comprises a winding pipe body. The winding pipe body is of a hollow structure and is formed by winding a continuous basalt fiber material infiltrated in epoxy resin group liquid or polyurethane resin group liquid; the winding pipe body is provided with an inner winding layer, a middle winding layer and an outer winding layer. Wherein the inner winding layer and the outer winding layer are annular spiral winding layers, and the middle winding layer is a longitudinal spiral winding layer; one middle winding layer is correspondingly wound on the periphery of one inner winding layer; the outer winding layer is wound on the periphery of the middle winding layer on the outermost layer. Compared with an existing glass fiber material, the continuous basalt fiber material has higher performance and can effectively avoid the situation of insulation breakdown in a high-voltage operation environment. And through the design of the inner winding layer, the middle winding layer and the outer winding layer, the performance of the winding pipe is further improved.

Description

Technical Field

[0001] This disclosure relates to the field of spiral wound tube technology, and in particular to a spiral wound tube for composite post insulators and its preparation method. Background Technology

[0002] With the development of power grid construction, post insulators are widely used in high-voltage and ultra-high-voltage transmission and transformation equipment, serving to support live conductors and provide electrical insulation. Among them, composite post insulators, through the combination of composite silicone rubber materials and insulating posts, effectively utilize the pollution resistance of silicone rubber skirts, and are therefore widely used in heavily polluted areas of my country.

[0003] Composite post insulators are mainly composed of fiber-wound tubes, end metal flanges, and silicone rubber sheaths. The fiber-wound tubes serve as the skeleton of the post insulator, mainly providing internal insulation and bearing mechanical loads (such as tensile, compressive, bending, and torsional resistance). Their performance directly affects the overall operating characteristics of the composite post insulator.

[0004] Currently, all existing composite post insulators use glass fiber as the load-bearing material. Although it has many advantages, in the production of ultra-high voltage and large-diameter composite post insulators, the thick walls of the spiral tubes require multiple winding and curing processes, which are complex. Furthermore, it is difficult to control the circumferential and longitudinal glass fibers during the winding process. As a result, the produced spiral tubes have a low elastic modulus and a large deformation under bending moment during operation. At the same time, multiple windings lead to high porosity between layers and an increase in the number of internal interfaces of the spiral tube, which poses a risk of insulation breakdown under long-term high-voltage operating conditions. Summary of the Invention

[0005] To address the aforementioned technical problems, this disclosure provides a composite post insulator winding tube and its preparation method.

[0006] In a first aspect, this disclosure provides a composite post insulator winding tube, which includes a winding tube body, the winding tube body having a hollow structure and being wound from continuous basalt fiber material impregnated with epoxy resin liquid or impregnated with polyurethane resin liquid. The wound tube body has an inner winding layer, a middle winding layer and an outer winding layer; Wherein, the inner winding layer and the outer winding layer are circumferential spiral winding layers, and the middle winding layer is a longitudinal spiral winding layer; One inner winding layer is wound around the outer periphery of another intermediate winding layer; the outer winding layer is wound around the outer periphery of the outermost intermediate winding layer.

[0007] In some embodiments, the spiral winding direction of the inner winding layer and the outer winding layer makes an angle of 85°-87° with the axial direction of the winding tube body, and / or, the spiral winding direction of the intermediate winding layer makes an angle of 5°-10° with the axial direction of the winding tube body.

[0008] In some embodiments, the thickness of the inner winding layer is 1.5mm-2.5mm, and / or the thickness of the outer winding layer is 2mm-3mm, and / or the thickness of the intermediate winding layer is 3mm-5mm.

[0009] The second aspect provides a method for preparing a composite post insulator winding tube, comprising the following steps: Step S1: Circumferentially spirally wind the continuous basalt fiber material impregnated with epoxy resin solution or polyurethane resin solution around the outer periphery of the winding tube mold to form the inner winding layer. Step S2: Longitudinally spirally wind continuous basalt fiber material impregnated with epoxy resin solution or polyurethane resin solution onto the outer surface of the inner winding layer to form the intermediate winding layer. Step S3: Measure whether the total thickness of the inner winding layer and the intermediate winding layer reaches the set thickness. If the set thickness is reached, proceed to step S4; otherwise, proceed to step S1. Step S4: Circumferentially spirally wind the continuous basalt fiber material impregnated with epoxy resin solution or polyurethane resin solution around the outer periphery of the intermediate winding layer to form the outer winding layer, thereby obtaining the semi-finished winding tube. Step S5: Place the semi-finished spiral tube into an oven for heating and curing; Step S6: Cool the semi-finished spiral tube at room temperature, remove the spiral tube mold from the semi-finished spiral tube to obtain the finished spiral tube, and polish the finished spiral tube.

[0010] In some embodiments, prior to step S1, the method further includes: Step S0: Prepare a spiral wound tube mold, and uniformly coat the surface of the spiral wound tube mold with a water-based release agent, and then lay a layer of transparent plastic film on it.

[0011] In some embodiments, step S1 further includes: With a spiral winding angle ranging from 85° to 87° and a pitch ranging from 5 mm to 10 mm, the spiral is repeatedly wound from bottom to top and then from top to bottom at least five times to form the inner winding layer with a thickness ranging from 1.5 mm to 2.5 mm.

[0012] In some embodiments, step S2 further includes: With a spiral winding angle ranging from 5° to 10° and a pitch ranging from 1500mm to 2000mm, the longitudinal spiral winding is repeated at least ten times from bottom to top and then from top to bottom to form the intermediate winding layer with a thickness ranging from 3mm to 5mm.

[0013] In some embodiments, step S3 further includes: With a spiral winding angle ranging from 85° to 87° and a pitch ranging from 5 mm to 10 mm, the spiral is repeatedly wound from bottom to top and then from top to bottom at least five times to form the outer winding layer with a thickness ranging from 2 mm to 3 mm.

[0014] In some embodiments, in steps S1, S2 and S4, the tension of the continuous basalt fiber material is 0.15KN-0.3KN.

[0015] In some embodiments, the method for preparing the composite post insulator winding tube further includes: Step S7: Perform product testing on the finished spiral tube. The product testing includes bending load test, deflection test, power frequency breakdown field strength test and high temperature aging test.

[0016] The technical solution provided in this disclosure has the following advantages compared with the prior art: This composite post insulator's spiral wound tube is made of continuous basalt fiber material impregnated with epoxy resin or polyurethane resin. Compared to existing glass fiber materials, continuous basalt fiber material has higher tensile strength and yield strength, better resistance to high and low temperatures, stronger insulation performance, stronger resistance to water damage, and is inexpensive and easy to process, effectively preventing insulation breakdown under high-voltage operating conditions. Furthermore, the composite post insulator's spiral wound tube has an inner winding layer, a middle winding layer, and an outer winding layer. The inner winding layer increases the internal insulation strength of the composite hollow post insulator and prevents flashover discharge along the inner insulation surface under operating voltage. The middle winding layer mechanically supports the weight of the charged conductor above the composite hollow post insulator. The outer winding layer increases the external insulation strength of the composite hollow post insulator and prevents flashover discharge under lightning impulse voltage, further enhancing the performance of the spiral wound tube.

[0017] The method for preparing the composite post insulator winding tube is used to prepare the above-mentioned composite post insulator winding tube. Its process is simple and efficient. By controlling the winding angle and tension, the gaps between the layers can be effectively reduced, and a composite post insulator winding tube with strong process performance parameters can be prepared. Attached Figure Description

[0018] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0019] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic cross-sectional view of the composite post insulator winding tube according to an embodiment of this disclosure; Figure 2 This is a schematic diagram of the circumferential spiral winding method described in the embodiments of this disclosure; Figure 3 This is a schematic diagram of the radial helical winding method described in the embodiments of this disclosure; Figure 4 This is a flowchart illustrating the preparation method of the composite post insulator winding tube according to an embodiment of this disclosure.

[0021] in: 1. Inner winding layer; 2. Middle winding layer; 3. Outer winding layer. Detailed Implementation

[0022] To better understand the above-mentioned objectives, features, and advantages of this disclosure, the solutions disclosed herein will be further described below. It should be noted that, unless otherwise specified, the embodiments and features described herein can be combined with each other.

[0023] Numerous specific details are set forth in the following description in order to provide a full understanding of this disclosure, but this disclosure may also be implemented in other ways different from those described herein; obviously, the embodiments in the specification are only some, and not all, of the embodiments of this disclosure.

[0024] Firstly, this embodiment provides a composite post insulator winding tube. Figure 1This is a cross-sectional schematic diagram of the composite post insulator winding tube described in this embodiment. The winding tube body has a hollow structure and is entirely made of continuous basalt fiber material impregnated with epoxy resin or polyurethane resin. Specifically, the epoxy resin in this embodiment refers to a mixture of epoxy resin, curing agent, and accelerator in a certain proportion. The polyurethane resin in this embodiment specifically refers to a mixture of polyol composite material (component A) and isocyanate composite material (component B) in a certain proportion. Before winding, the continuous basalt fiber material is first impregnated with epoxy resin or polyurethane resin for 1-2 minutes at an impregnation temperature of 20℃-30℃ to improve the performance of the continuous basalt fiber material.

[0025] Furthermore, such as Figure 1 As shown, the wound tube body has an inner winding layer 1, an intermediate winding layer 2, and an outer winding layer 3; Both inner winding layer 1 and outer winding layer 3 are Figure 2 The circumferential spiral winding layer shown, that is, both the inner winding layer 1 and the outer winding layer 3 adopt a circumferential spiral winding method around the outer periphery of the winding tube body, while the middle winding layer 2 is a longitudinal spiral winding layer. Figure 3 The diagram shows a longitudinal spiral winding method around the outer periphery of the winding tube body.

[0026] An inner winding layer 1 is wrapped around the outer periphery of an intermediate winding layer 2, and an outer winding layer 3 is wrapped around the outer periphery of the outermost intermediate winding layer 2.

[0027] For example, in some embodiments, the inner winding layer 1 and the intermediate winding layer 2 have the same number of layers and are connected in a one-to-one correspondence, such as... Figure 1 As shown, the inner winding layer 1 and the intermediate winding layer 2 can each be provided with one layer. An intermediate winding layer 2 is provided on the outer periphery of the inner winding layer 1, and an outer winding layer 3 is provided on the outer periphery of the intermediate winding layer 2, so that the winding tube body forms a three-layer winding structure.

[0028] However, in other embodiments, the inner winding layer 1 and the intermediate winding layer 2 may be provided in multiple layers. For example, the inner winding layer 1 and the intermediate winding layer 2 may each be provided in two layers. That is, an intermediate winding layer 2 is provided outside an inner winding layer 1, and another inner winding layer 1 is wound outside the intermediate winding layer 2. Another intermediate winding layer 2 is wound outside the inner winding layer 1, and the outer winding layer 3 is wound around the outermost intermediate winding layer 2, so that the winding tube body forms a five-layer winding structure. The number of inner winding layer 1 and intermediate winding layer 2 is selected according to the actual situation. In this embodiment, the number of inner winding layer 1 and intermediate winding layer 2 is not specifically limited.

[0029] The spiral tube body of this embodiment consists of an inner spiral layer 1, an intermediate spiral layer 2, and an outer spiral layer 3. The inner spiral layer 1 increases the internal insulation strength of the composite hollow post insulator and prevents flashover discharge along the inner insulation surface under operating voltage. The intermediate spiral layer 2 mechanically supports the weight of the charged conductor above the composite hollow post insulator. The outer spiral layer 3 increases the external insulation strength of the composite hollow post insulator and prevents flashover discharge under lightning impulse voltage. This embodiment utilizes continuous basalt fiber material to manufacture the spiral tube. Compared to existing glass fiber materials, continuous basalt fiber material has higher tensile strength and yield strength, better resistance to high and low temperatures, stronger insulation performance, stronger resistance to water damage, and is inexpensive and easy to process. It can effectively avoid insulation breakdown under high-voltage operating conditions and is suitable for the production of ultra-high voltage or extra-high voltage and large-diameter load post insulators.

[0030] Furthermore, the composite post insulator winding tube has an inner winding layer, a middle winding layer, and an outer winding layer. The inner winding layer can increase the internal insulation strength of the composite hollow post insulator and prevent flashover discharge along the inner insulation surface under operating voltage. The middle winding layer can mechanically support the weight of the charged conductor above the composite hollow post insulator. The outer winding layer can increase the external insulation strength of the composite hollow post insulator and prevent flashover discharge under lightning impulse voltage, which is conducive to further improving the performance of the winding tube.

[0031] In some embodiments, the spiral winding direction of the inner winding layer 1 and the outer winding layer 3 forms an angle of 85°-87° with the axial direction of the winding tube body, and / or, the spiral winding direction of the intermediate winding layer 2 forms an angle of 5°-10° with the axial direction of the winding tube body.

[0032] In some embodiments, the thickness of the inner winding layer 1 is 1.5mm-2.5mm, and / or the thickness of the outer winding layer 3 is 2mm-3mm, and / or the thickness of the intermediate winding layer 2 is 3mm-5mm.

[0033] In some embodiments, continuous basalt fiber material specifically refers to basalt fiber untwisted roving or basalt fiber cloth. The basalt fiber untwisted roving has a monofilament diameter of 6μm-24μm, a linear density of 1500Tex-4800Tex, a tensile strength ≥3000MPa, and a flexural strength ≥850MPa. The basalt fiber cloth has an area density of 400g / m²-800 g / m², a monofilament diameter of 9μm-17μm, and a tensile strength of 3000MPa-4840MPa.

[0034] Secondly, this embodiment provides a method for preparing a composite post insulator winding tube, such as... Figure 4As shown, the process for preparing the aforementioned composite post insulator winding tube is simple and highly efficient. By controlling the winding angle and tension, the porosity between the layers can be effectively reduced, resulting in a composite post insulator winding tube with strong process performance parameters. Specifically, it includes the following steps: Step S1: Circumferentially spirally wind continuous basalt fiber material impregnated with epoxy resin solution or polyurethane resin solution around the outer periphery of the winding tube mold to form inner winding layer 1.

[0035] Specifically, in step S1, continuous basalt fiber material impregnated with epoxy resin or polyurethane resin is spirally wound at an angle ranging from 85° to 87° and a pitch ranging from 5 mm to 10 mm, repeating the circumferential spiral winding at least five times from bottom to top and then from top to bottom to form an inner winding layer 1 with a thickness ranging from 1.5 mm to 2.5 mm. The spiral winding angle mentioned in this embodiment is the angle between the winding direction of the continuous basalt fiber material and the axial direction of the winding tube. Preferably, the tension force of the continuous basalt fiber material is controlled between 0.15 KN and 0.3 KN.

[0036] Step S2: The continuous basalt fiber material impregnated with epoxy resin solution or polyurethane resin solution is longitudinally spirally wound onto the outer surface of the inner winding layer 1 to form the intermediate winding layer 2.

[0037] Specifically, in step S2, continuous basalt fiber material impregnated with epoxy resin or polyurethane resin is spirally wound at an angle ranging from 5° to 10° and a pitch ranging from 1500 mm to 2000 mm, repeating this longitudinal spiral winding at least ten times from bottom to top and then from top to bottom to form an intermediate winding layer 2 with a thickness ranging from 3 mm to 5 mm. This spiral winding angle is also the angle between the winding direction of the continuous basalt fiber material and the axial direction of the winding tube. Preferably, the tension force of the continuous basalt fiber material is controlled between 0.15 KN and 0.3 KN.

[0038] Step S3: Measure whether the total thickness of the inner winding layer 1 and the intermediate winding layer 2 reaches the set thickness. If the set thickness is reached, proceed to step S4; otherwise, proceed to step S1.

[0039] Specifically, in step S3, after the inner winding layer 1 and the intermediate winding layer 2 are wound, the total thickness of the wound inner winding layer 1 and the intermediate winding layer 2 is measured to see if it reaches the set thickness. If the total thickness reaches the set thickness requirement, the process proceeds to the next step S4; otherwise, it re-enters step S1 and re-wound the inner winding layer 1 and the intermediate winding layer 2 until the total thickness meets the requirement. The total thickness of the wound inner winding layer 1 and the intermediate winding layer 2 is determined according to the actual design requirements. This embodiment does not specifically limit the total thickness of the inner winding layer 1 and the intermediate winding layer 2.

[0040] Step S4: Circumferentially spirally wind the continuous basalt fiber material impregnated with epoxy resin solution or polyurethane resin solution around the outer periphery of the intermediate winding layer 2 to form the outer winding layer 3, thereby obtaining the semi-finished winding tube.

[0041] Specifically, in step S4, after the total thickness of the inner winding layer 1 and the intermediate winding layer 2 reaches the standard, the outermost intermediate winding layer 2 is spirally wound at least five times from bottom to top and then from top to bottom, with a spiral winding angle ranging from 85° to 87° and a pitch ranging from 5mm to 10mm, to form an outer winding layer 3 with a thickness ranging from 2mm to 3mm. Preferably, the tension of the continuous basalt fiber material is controlled between 0.15KN and 0.3KN.

[0042] Step S5: Place the semi-finished spiral wound tube into an oven for heating and curing.

[0043] Specifically, in step S5, the semi-finished spiral tube is placed in a sealed oven and cured at a temperature of 55℃-70℃ for 4-6 hours.

[0044] Step S6: Cool the semi-finished spiral tube at room temperature, remove the spiral tube mold from the semi-finished spiral tube to obtain the finished spiral tube, and polish the finished spiral tube.

[0045] Specifically, in step S6, the dried and cured semi-finished spiral wound tube is taken out of the oven. After cooling to room temperature, the semi-finished spiral wound tube is demolded, the spiral wound tube mold is removed from the semi-finished spiral wound tube, and the finished spiral wound tube is obtained. The end material and fuzzy areas of the finished spiral wound tube are repaired, and the inner and outer surfaces are polished.

[0046] It is also worth noting that, in this embodiment, the spiral winding angle and tension of the continuous basalt fiber material can be changed to obtain the finished winding tube under different process control parameters.

[0047] In addition, in some embodiments, before step S1, there is a step S0: preparing a winding tube mold, uniformly coating the surface of the winding tube mold with a water-based release agent, and then laying a layer of transparent plastic film.

[0048] Specifically, in step S0, a winding tube mold is prepared before preparing the winding tube. Optionally, the winding tube mold is cylindrical and made of stainless steel, with a gear structure at one end to facilitate rotation driven by a motor, enabling circumferential and longitudinal winding of the continuous basalt fiber material. To facilitate subsequent demolding, a water-based release agent is uniformly coated on the surface of the winding tube mold, and then a layer of transparent plastic film is laid on top, allowing the continuous basalt fiber material to be wound onto the plastic film. Optionally, the water-based release agent can be obtained by mixing water-based polyurethane resin, water, ethanol, cationic surfactants (such as sodium alkylbenzene sulfonate), and dispersants (such as polyvinyl alcohol) in a certain proportion.

[0049] Furthermore, in some embodiments, step S7 is included after step S6: Step S7: Conduct product testing on the finished spiral wound tube. Product testing includes bending load testing, deflection testing, power frequency breakdown field strength testing, and high temperature aging testing. Step S7 mainly tests the finished spiral wound tube to verify whether its current performance parameters meet the usage requirements.

[0050] Bending load and deflection tests are conducted on a bending and torsion testing machine. Before the test, the bottom end of the finished spiral tube is firmly fixed to the test fixture using a special component. Then, the mechanical load applied to the top of the specimen is gradually increased through the loading mechanism of the bending and torsion testing machine. The load direction should always be perpendicular to the axial direction of the specimen. When the specimen fails, the value of the applied load and the corresponding maximum deformation of the specimen are the bending load and deflection of the basalt fiber spiral tube being tested.

[0051] The power frequency breakdown field strength test is conducted according to IEC 60243-1:2013 "Electrical strength of insulating materials - Test methods - Part 1: Industrial frequency test". A rectangular sample is cut from the finished spiral wound tube and placed in a transparent glass container filled with dimethyl silicone oil, ensuring that the silicone oil covers the sample by 5 mm to 7 mm. A power frequency operating voltage is applied to the sample through a test transformer until the rectangular sample undergoes a through-discharge breakdown. The breakdown voltage value is recorded, and the power frequency breakdown field strength of the rectangular sample is calculated based on the thickness parameters. During the test, the arithmetic mean of the power frequency breakdown field strength at least 10 test points is taken as the power frequency breakdown field strength of the basalt fiber spiral wound tube.

[0052] The high-temperature aging test involves placing the finished spiral wound tube in a boiling tank with a sodium chloride to deionized water mass ratio of 1:1000 and boiling it at 100°C for 42 hours. Then, it is removed from the boiling tank and placed in another boiling tank filled with deionized water, where it is immersed at room temperature for 2 hours. After removal, it is air-dried and the surface moisture is wiped dry with filter paper. Finally, the finished spiral wound tube is placed in a high-temperature aging chamber with the temperature set at 110°C. A power frequency operating voltage is applied to the finished spiral wound tube through the high-voltage test power supply of the aging test chamber, and the leakage current under the power frequency operating voltage is tested to detect relevant performance parameters.

[0053] For example, this application uses a 500KV composite post insulator winding tube with a wall thickness of 50mm, a diameter of 500mm, and a length of 5m as an example to illustrate in detail the preparation method of the winding tube.

[0054] Step S0: Prepare a spiral wound tube mold, and uniformly coat the surface of the spiral wound tube mold with a water-based release agent, and then lay a layer of transparent plastic film on it.

[0055] In this step, the winding tube mold is a specially made cylindrical mold made of Q235 stainless steel, and a layer of water-based release agent is evenly coated on its surface. One end of the winding tube mold has a gear structure to facilitate rotation driven by a motor, realizing the circumferential and longitudinal winding of continuous basalt fiber material. The water-based release agent is prepared by mixing water-based polyurethane resin, water, ethanol, cationic surfactant (such as sodium alkylbenzene sulfonate) and dispersant (such as polyvinyl alcohol) in the following mass percentages: (13.5-15.5)%, (35-55)%, (30-50)%, (0.4-0.9)%, and (0.2-1.3)%.

[0056] Step S1: Circumferentially spirally wind continuous basalt fiber material impregnated with epoxy resin solution or polyurethane resin solution around the outer periphery of the winding tube mold to form inner winding layer 1.

[0057] In this step, the first step is to prepare the required continuous basalt fiber material, epoxy resin system, and polyurethane resin system materials for the 500kV composite post insulator winding tube. The continuous basalt fiber material is impregnated in the epoxy resin or polyurethane resin solution for 1-2 minutes at a temperature of 20-30℃. Specifically, the continuous basalt fiber material refers to basalt fiber roving or basalt fiber cloth. The main technical parameters of the basalt fiber roving are shown in Table 1, and the main technical parameters of the basalt fiber cloth are shown in Table 2.

[0058] Table 1. Main Technical Parameters of Basalt Fiber Untwisted Roving

[0059] Table 2 Main Technical Parameters of Basalt Fiber Cloth

[0060] Among them, epoxy resin system material refers to a solution obtained by mixing epoxy resin, curing agent and accelerator in a mass percentage ratio of (50-65)%, (30-35)% and (30-35)%.

[0061] Among them, polyurethane resin system material refers to a solution obtained by mixing polyol composition (component A) and isocyanate composition (component B) in a mass percentage ratio of (45-55)% and (45-55)%.

[0062] Continuous basalt fiber material impregnated with epoxy resin or polyurethane resin is spirally wound around the outer surface of the winding tube mold in step S0 under a tension force of 0.15kN-0.30kN. Specifically, the continuous basalt fiber is spirally wound from the bottom end to the top end of the winding tube mold and then spirally wound from the top end to the bottom end, repeating this process five times. The spiral winding angle (the angle between the winding direction and the axial direction of the winding tube mold) is 85°-87° and the pitch is 5 mm-10 mm, thus forming the inner winding layer 1 of the 500kV composite post insulator winding tube. The thickness of a single inner winding layer 1 is controlled between 2.0 mm and 2.5 mm.

[0063] Step S2: The continuous basalt fiber material impregnated with epoxy resin solution or polyurethane resin solution is longitudinally spirally wound onto the outer surface of the inner winding layer 1 to form the intermediate winding layer 2.

[0064] In this step, continuous basalt fiber material impregnated with epoxy resin or polyurethane resin is used. Under a tension force of 0.15kN-0.30kN, it is longitudinally spirally wound onto the surface of the inner winding layer 1 in step S1 using a "small angle winding process". Specifically, the continuous basalt fiber material is longitudinally wound from the bottom end to the top end of the inner winding layer 1, and then longitudinally wound from the top end to the bottom end, repeating this process 10 times. The winding angle is 5°-10° and the pitch is 1500 mm-2000 mm, thus forming the intermediate winding layer 2 of the 500kV composite post insulator winding tube. The thickness of a single intermediate winding layer 2 is controlled between 4.5 mm and 5.0 mm.

[0065] Step S3: Measure whether the total thickness of the inner winding layer 1 and the intermediate winding layer 2 reaches the set thickness. If the set thickness is reached, proceed to step S4; otherwise, proceed to step S1.

[0066] In this step, steps S1 and S2 are repeated several times until the wall thickness of the 500kV composite post insulator winding tube is within the range of 50±2.5mm. This embodiment does not specify the specific number of winding cycles.

[0067] Step S4: Circumferentially spirally wind the continuous basalt fiber material impregnated with epoxy resin solution or polyurethane resin solution around the outer periphery of the intermediate winding layer 2 to form the outer winding layer 3, thereby obtaining the semi-finished winding tube.

[0068] In this step, continuous basalt fiber material impregnated with epoxy resin or polyurethane resin is spirally wound around the outer surface of the intermediate winding layer 2 in step S3 under a tension force of 0.15kN-0.30kN. Specifically, the continuous basalt fiber is spirally wound from the bottom to the top of the intermediate winding layer 2, and then spirally wound from the top to the bottom, repeating this process five times. The spiral winding angle is 85° to 87° and the pitch is 5-10mm, thus forming the outer winding layer 3 of the 500kV composite post insulator winding tube. The thickness of the outermost outer winding layer 3 is controlled between 4.5mm and 5.0mm.

[0069] Step S5: Place the semi-finished spiral wound tube into an oven for heating and curing.

[0070] In this step, the 500kV composite post insulator winding tube semi-finished product (along with the winding tube mold) is placed in a sealed oven and cured at a temperature of 55-70℃ for 4-6 hours.

[0071] Step S6: Cool the semi-finished spiral tube at room temperature, remove the spiral tube mold from the semi-finished spiral tube to obtain the finished spiral tube, and polish the finished spiral tube.

[0072] In this step, the semi-finished 500kV composite post insulator spiral wound tube is taken out of the oven. When it cools to room temperature, the semi-finished spiral wound tube is separated from the spiral wound tube mold under the action of the release agent and transparent plastic film. Then, the end material and fuzzy parts of the semi-finished spiral wound tube are repaired and the inner and outer surfaces are polished to obtain the finished 500kV composite post insulator spiral wound tube.

[0073] Subsequently, based on this, the longitudinal winding angles were set to 5°, 8°, and 10°, and the tension forces were set to 0.15kN, 0.20kN, and 0.25kN, respectively. Steps S1 to S6 were repeated to obtain 500kV composite post insulator winding tubes prepared under different process control parameters, which were numbered 01 to 09. Then, step S7 was taken to conduct bending load tests, deflection tests, power frequency breakdown field strength tests, and high temperature aging tests on the above nine groups of winding tubes.

[0074] in: Bending load and deflection test: The test is conducted on a bending and torsion testing machine. Before the test, the bottom end of the 500kV composite post insulator winding tube is firmly fixed to the test fixture using a special component. Then, the mechanical load applied to the top of the specimen is gradually increased through the loading mechanism of the bending and torsion testing machine. The load direction should always be perpendicular to the axial direction of the specimen. When the specimen fails, the value of the applied load and the corresponding maximum deformation of the specimen are the bending load and deflection of the basalt fiber material winding tube being tested.

[0075] Power frequency breakdown field strength test: According to IEC 60243-1:2013 "Electrical strength of insulating materials - Test methods - Part 1: Industrial frequency test", a rectangular sample is cut from the finished basalt fiber wound tube and placed in a transparent glass container filled with dimethyl silicone oil, ensuring that the silicone oil covers the sample by 5 mm-7 mm. A power frequency operating voltage is applied to the sample through a test transformer until the rectangular sample undergoes a through-discharge breakdown. The breakdown voltage value is recorded and the power frequency breakdown field strength of the rectangular sample is calculated based on the thickness parameters. During the test, the arithmetic mean of the power frequency breakdown field strengths at least 10 test points is taken as the power frequency breakdown field strength of the basalt fiber wound tube.

[0076] High-temperature aging test: The basalt fiber material wound tube was placed in a water boiling tank with a sodium chloride to deionized water mass ratio of 1:1000 and boiled at 100℃ for 42 hours; then it was removed from the water boiling tank and placed in another water boiling tank filled with deionized water and immersed at room temperature for 2 hours. After removal, it was air-dried and the surface moisture was wiped off with filter paper; finally, the basalt fiber material wound tube was placed in a high-temperature aging chamber with the temperature set at 110℃. A power frequency operating voltage of 288.7kV was applied to the basalt fiber material wound tube through the high-voltage test power supply of the aging test chamber, and the leakage current under the power frequency operating voltage was tested.

[0077] After completing the above tests, the performance test results of the nine groups of 500kV composite post insulator winding tubes are shown in Table 3 below.

[0078] Table 3 Performance test results of 500kV composite post insulator spiral tube

[0079] According to the test results in Table 3, when the longitudinal winding angle of the basalt fiber material increases from 5° to 8°, the bending load and power frequency breakdown field strength of the basalt fiber material wound tube first increase and then decrease, while the deflection and high-temperature aging test leakage current first decrease and then increase. Furthermore, when the longitudinal winding angle is 5° and 8°, as the circumferential and longitudinal winding tension of the basalt fiber material increases from 0.15kN to 0.25kN, the bending load and power frequency breakdown field strength of the basalt fiber material wound tube gradually increase, while the deflection and high-temperature aging test leakage current gradually decrease. When the longitudinal winding angle is 10°, as the circumferential and longitudinal winding tension increases, the bending load and power frequency breakdown field strength first increase and then decrease sharply, while the deflection and high-temperature aging test leakage current first decrease and then increase sharply, and the leakage current is close to the unqualified value (≥50μA is unqualified). This indicates that the longitudinal winding angle has a greater impact on the performance of the basalt fiber epoxy wound tube than the tension force. Based on the above analysis, the optimal manufacturing process parameters for the basalt fiber material winding tube of the 500kV composite post insulator are proposed as follows: the longitudinal winding angle is 5°-8°, and the circumferential and longitudinal winding tension is 0.20-0.25kN.

[0080] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0081] The above description is merely a specific embodiment of this disclosure, enabling those skilled in the art to understand or implement it. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this disclosure. Therefore, this disclosure is not to be limited to the embodiments described herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A composite post insulator winding tube, characterized in that, include: The wound tube body has a hollow structure and is made of continuous basalt fiber material impregnated with epoxy resin liquid or polyurethane resin liquid. The wound tube body has an inner winding layer (1), an intermediate winding layer (2) and an outer winding layer (3); Wherein, the inner winding layer (1) and the outer winding layer (3) are circumferential spiral winding layers, and the middle winding layer (2) is a longitudinal spiral winding layer; The outer periphery of the inner winding layer (1) is correspondingly wound with the middle winding layer (2); the outer winding layer (3) is wound around the outer periphery of the outermost middle winding layer (2).

2. The composite post insulator winding tube according to claim 1, characterized in that, The spiral winding direction of the inner winding layer (1) and the outer winding layer (3) is at an angle of 85°-87° with the axial direction of the winding tube body, and / or the spiral winding direction of the intermediate winding layer (2) is at an angle of 5°-10° with the axial direction of the winding tube body.

3. The composite post insulator winding tube according to claim 1, characterized in that, The thickness of the inner winding layer (1) is 1.5mm-2.5mm, and / or the thickness of the outer winding layer (3) is 2mm-3mm, and / or the thickness of the intermediate winding layer (2) is 3mm-5mm.

4. A method for preparing a composite post insulator winding tube, characterized in that, The method for preparing the composite post insulator winding tube according to any one of claims 1-3 comprises the following steps: Step S1: Circumferentially spirally wind the continuous basalt fiber material impregnated with epoxy resin solution or polyurethane resin solution around the outer periphery of the winding tube mold to form the inner winding layer (1). Step S2: Longitudinally spirally wind the continuous basalt fiber material impregnated with epoxy resin solution or polyurethane resin solution onto the outer surface of the inner winding layer (1) to form the intermediate winding layer (2). Step S3: Measure whether the total thickness of the inner winding layer (1) and the intermediate winding layer (2) reaches the set thickness. If the set thickness is reached, proceed to step S4; otherwise, proceed to step S1. Step S4: Circumferentially spirally wind the continuous basalt fiber material impregnated with epoxy resin solution or polyurethane resin solution around the outer periphery of the intermediate winding layer (2) to form the outer winding layer (3), thereby obtaining the semi-finished winding tube. Step S5: Place the semi-finished spiral tube into an oven for heating and curing; Step S6: Cool the semi-finished spiral tube at room temperature, remove the spiral tube mold from the semi-finished spiral tube to obtain the finished spiral tube, and polish the finished spiral tube.

5. The method for preparing the composite post insulator winding tube according to claim 4, characterized in that, Before step S1, the procedure also includes: Step S0: Prepare a spiral wound tube mold, and uniformly coat the surface of the spiral wound tube mold with a water-based release agent, and then lay a layer of transparent plastic film on it.

6. The method for preparing the composite post insulator winding tube according to claim 4, characterized in that, Step S1 further includes: The inner winding layer (1) with a spiral winding angle in the range of 85°-87° and a pitch range of 5mm-10mm is repeatedly spiral wound from bottom to top and then from top to bottom at least five times to form a thickness range of 1.5mm-2.5mm.

7. The method for preparing the composite post insulator winding tube according to claim 4, characterized in that, Step S2 further includes: With a spiral winding angle ranging from 5° to 10° and a pitch ranging from 1500mm to 2000mm, the longitudinal spiral winding is repeated at least ten times from bottom to top and then from top to bottom to form the intermediate winding layer (2) with a thickness ranging from 3mm to 5mm.

8. The method for preparing the composite post insulator winding tube according to claim 4, characterized in that, Step S3 further includes: With a spiral winding angle ranging from 85° to 87° and a pitch ranging from 5 mm to 10 mm, the spiral winding is repeated at least five times from bottom to top and then from top to bottom to form the outer winding layer (3) with a thickness ranging from 2 mm to 3 mm.

9. The method for preparing the composite post insulator winding tube according to claim 4, characterized in that, In steps S1, S2, and S4, the tension of the continuous basalt fiber material is 0.15KN-0.3KN.

10. The method for preparing the composite post insulator winding tube according to claim 4, characterized in that, It also includes: Step S7: Perform product testing on the finished spiral tube. The product testing includes bending load test, deflection test, power frequency breakdown field strength test and high temperature aging test.

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