Terminal for power cable and manufacturing method thereof

Abstract

The invention discloses a terminal for a power cable and a manufacturing method of the terminal, an epoxy pipe sleeve is divided into an air insulation section and a solid insulation section by reasonably arranging a stress control cone and an annular rubber cone, and further according to the working voltage level of the terminal for the power cable, the solid insulation section is separated from the air insulation section. The electric field bearing strength per unit length of the air insulation section is reasonably configured, so that the air insulation section can meet the insulation requirement only by being filled with normal-pressure air, the insulation strength of the terminal gas part is improved without depending on insulation gas or oil, and the sealing requirement of the terminal can be effectively reduced by adopting normal-pressure air filling; and environmental pollution caused by leakage of the insulating medium is not required to be worried. Meanwhile, by arranging the conical shielding cover, sealing of the top end of the epoxy pipe sleeve and cable point discharge shielding can be directly achieved, and the overall function of the terminal for the normal-pressure air power cable is further guaranteed. In addition, the terminal is insulated by normal-pressure air, medium filling is not needed, and assembly type manufacturing can be conveniently completed in a prefabrication mode.

Description

Technical Field

[0001] The present application relates to the field of cable terminals, and in particular to a terminal for a power cable and a manufacturing method thereof. Background Art

[0002] Early power cable terminals were mostly insulated with oil or SF6 gas, which poses leakage risks and fails to meet environmental requirements. For example, gas-insulated transmission lines rely on SF6 gas, but its greenhouse gas potential is 23,500 times that of CO2, and leakage poses a threat to the ecological environment. Furthermore, oil-immersed insulation structures also carry the risk of leakage pollution, making them difficult to meet the requirements of green grid construction. Summary of the Invention

[0003] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes a power cable terminal and a manufacturing method thereof, which can directly use air as the insulating medium, thereby solving the problem that the conventional terminal filling medium is prone to leakage, polluting the environment, and failing to meet insulation requirements.

[0004] A power cable terminal according to an embodiment of the first aspect of the present application includes: The base has a first through hole for the cable to pass through; the top end of the cable is connected to a connecting hardware; An insulating sleeve, the bottom end of which is connected to the base, wherein an annular rubber cone is prefabricated in the insulating sleeve; a second through hole is formed in the annular rubber cone, and the aperture of the second through hole at the end away from the base is smaller than the aperture at the end close to the base; a supporting rubber member, disposed on the base and located in the second through hole, the supporting rubber member having a third through hole for the cable to pass through; A stress control cone having a fourth through hole for the cable to pass through; the stress control cone is supported by the supporting rubber member so that the outer surface of the stress control cone is in contact with the inner surface of the second through hole; within the insulating sleeve, the annular rubber cone and the stress control cone are above the top of the air insulation section, and the solid insulation section is below the top, and the air insulation section is filled with air at normal pressure; the electric field strength per unit length of air in the height direction of the air insulation section is within a preset field strength tolerance range, wherein the numerical value of the value range corresponding to the preset field strength tolerance range is positively correlated with the operating voltage level of the power cable terminal; a conical shielding cover having a fifth through hole for the connecting fitting to pass through, wherein the bottom end of the conical shielding cover is connected to the top of the insulating sleeve and forms a seal with the top of the insulating sleeve; An auxiliary fastener is used to connect the connecting hardware and the conical shielding cover and to form a seal on the top end of the conical shielding cover.

[0005] A method for manufacturing a power cable terminal according to an embodiment of the second aspect of the present application includes: Passing the cable through the first through hole of the base, wherein the cable is pre-processed to expose the connecting conductor; Passing the cable through the third through hole of the supporting rubber member, and fixing the supporting rubber member to the base; Passing the cable through the fourth through hole of the stress control cone, and pushing the stress control cone downward until it contacts the supporting rubber member with a certain pressing force; Connecting the connecting fitting to the connecting conductor of the cable; The cable is passed through the second through hole of the insulating sleeve, and the insulating sleeve is pushed down until it is in close contact with the stress control cone; wherein, an annular rubber cone is prefabricated in the insulating sleeve; the annular rubber cone has the second through hole, and the aperture of the second through hole at the end away from the base is smaller than the aperture at the end close to the base; in the insulating sleeve, the area above the top of the annular rubber cone and the stress control cone is an air insulation section, and the area below the top is a solid insulation section, and the air insulation section is filled with air at normal pressure; the electric field strength per unit length of air in the height direction of the air insulation section is within a preset field strength tolerance range, wherein the numerical value of the value range corresponding to the preset field strength tolerance range is positively correlated with the working voltage level of the terminal for the power cable; Fixing the bottom end of the insulating sleeve to the base; Passing the connecting hardware through the fifth through-hole of the conical shielding cover, and fixing the conical shielding cover to the top end of the insulating sleeve; A secondary fastener is used to form a seal on the top end of the conical shield.

[0006] The power cable terminal and its manufacturing method of the embodiment of the present application, by reasonably setting the stress control cone and the annular rubber cone, divides the epoxy tube sleeve into an air insulation section and a solid insulation section, and further reasonably configures the electric field bearing strength per unit length of the air insulation section according to the working voltage level of the power cable terminal, so that the air insulation section can meet the insulation requirements by only filling it with normal pressure air, without relying on insulating gas or oil to enhance the insulation strength of the terminal gas part, and the use of normal pressure air filling can effectively reduce the sealing requirements of the terminal, and there is no need to worry about environmental pollution caused by leakage of the insulating medium. At the same time, by setting a conical shielding cover, the sealing of the top of the epoxy tube sleeve and the discharge shielding of the cable tip can be directly achieved, further ensuring the overall function of the normal pressure air power cable terminal. In addition, the terminal uses normal pressure air insulation and does not require dielectric filling, which facilitates the use of prefabrication to complete assembly production, greatly improving the convenience of manufacturing and installation, and is more suitable for use in scenarios with higher time requirements such as emergency repairs.

[0007] Other features and advantages of the present application will be set forth in the following description, and in part will be apparent from the description, or may be learned by practicing the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The present application is further described below with reference to the accompanying drawings and embodiments, wherein: Figure 1 This is a schematic structural diagram of a power cable terminal according to an embodiment of the present application; Figure 2 This is a schematic structural diagram of an insulating sleeve according to an embodiment of the present application; Figure 3 This is a schematic structural diagram of a stress control cone according to an embodiment of the present application; Figure 4 for Figure 1 A top enlarged schematic diagram of Figure 5 This is a flow chart of a method for manufacturing a power cable terminal according to an embodiment of the present application.

[0009] Figure Number: Base 100; insulating sleeve 200; support tube 210; upper flange 220; silicone rubber shed 230; lower flange 240; annular rubber cone 250; supporting rubber part 300; stress control cone 400; semi-conductive stress control part 410; conical shielding cover 500; auxiliary fastener 600; tightening ring 610; gland 620; rain cover 700; supporting insulator 800; tail grounding sealing tube 900; cable 1000; connecting hardware 1100; normal pressure air 1200. DETAILED DESCRIPTION

[0010] The following describes in detail embodiments of the present application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application.

[0011] In the description of this application, it should be understood that descriptions involving orientation, such as the orientation or positional relationship indicated by up, down, etc., are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0012] In the description of this application, "a plurality" refers to more than two. The use of "first" or "second" is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or implicitly indicating the order of the technical features indicated.

[0013] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0014] refer to Figures 1 to 4 , the present application proposes a terminal for a power cable, the terminal for a power cable comprising: The base 100 has a first through hole for the cable 1000 to pass through; the top of the cable 1000 is connected to a connecting hardware 1100; The insulating sleeve 200 has its bottom end connected to the base 100. An annular rubber cone 250 is prefabricated in the insulating sleeve 200. The annular rubber cone 250 has a second through hole. The diameter of the second through hole at the end away from the base 100 is smaller than the diameter at the end close to the base 100. The supporting rubber member 300 is provided on the base 100 and is located in the second through hole. The supporting rubber member 300 has a third through hole for the cable 1000 to pass through. The stress control cone 400 has a fourth through hole for the cable 1000 to pass through. The stress control cone 400 is supported by the supporting rubber member 300 so that the outer surface of the stress control cone 400 is in contact with the inner surface of the second through hole. Within the insulating sleeve 200, the area above the top of the annular rubber cone 250 and the stress control cone 400 is an air-insulated section, and below the top is a solid-insulated section. The air-insulated section is filled with atmospheric pressure air 1200. The electric field strength per unit length of air in the height direction of the air-insulated section is within a preset field strength tolerance range, wherein the numerical value range corresponding to the preset field strength tolerance range is positively correlated with the operating voltage level of the power cable terminal. The conical shielding cover 500 has a fifth through hole for the connecting hardware 1100 to pass through. The bottom end of the conical shielding cover 500 is connected to the top of the insulating sleeve 200 and forms a seal with the top of the insulating sleeve 200. The auxiliary fastener 600 is used to connect the connecting fitting 1100 and the conical shielding cover 500 and to form a seal on the top of the conical shielding cover 500 .

[0015] In the embodiment of the present application, by rationally setting the stress control cone 400 and the annular rubber cone 250, the epoxy tube sleeve is divided into an air-insulated section and a solid-insulated section. Furthermore, based on the operating voltage level of the power cable terminal, the electric field strength per unit length of the air-insulated section is rationally configured, so that the air-insulated section can meet the insulation requirements by simply filling it with atmospheric pressure air 1200, without relying on insulating gas or oil to enhance the insulation strength of the terminal gas portion. Furthermore, the use of atmospheric pressure air 1200 for filling effectively reduces the sealing requirements of the terminal and eliminates the need to worry about environmental pollution caused by leakage of the insulating medium. Simultaneously, by providing a conical shielding cover 500, the top of the epoxy tube sleeve can be directly sealed and the cable 1000 tip can be shielded from discharge, further ensuring the overall functionality of the atmospheric pressure air 1200 power cable terminal. Furthermore, the terminal utilizes atmospheric pressure air 1200 for insulation, eliminating the need for dielectric filling, making it easy to prefabricate and complete assembly, significantly improving the ease of manufacturing and installation, making it more suitable for use in time-sensitive scenarios such as emergency repairs. In addition, leakage of insulating oil can easily cause combustion and explosion, posing a greater safety risk. When using insulating gas for filling, high-pressure gas needs to be used, making the insulating terminal prone to explosion due to high pressure, which also poses a greater safety risk.

[0016] The insulating sleeve 200 is prefabricated with an annular rubber cone 250 , which can be prefabricated by bonding. Specifically, an AB component adhesive can be used for bonding.

[0017] The annular rubber cone 250 may be a high-hardness, environmentally friendly rubber cone.

[0018] The supporting rubber member 300 is used to support the stress control cone 400, so that after the power cable terminal is installed, the semi-conductive stress control member 410 inside the stress control cone 400 can be flush with the end of the semi-conductive layer of the cable 1000. It also allows the stress control cone 400 to adhere tightly to the inner wall of the annular rubber cone 250, eliminating the need for bonding.

[0019] The inner wall of the annular rubber cone 250 is arranged in a conical inclined surface, and the outer surface of the stress control cone 400 is arranged in a conical inclined surface adapted to the inner wall of the annular rubber cone 250. After the stress control cone 400 is supported in place, the supporting rubber member 300 can fix the position of the stress control cone 400 and make the top of the stress control cone 400 flush with the top of the annular rubber cone 250, so as to subsequently form a regular solid insulation section and an air insulation section.

[0020] The stress control cone 400 and the annular rubber cone 250 form a solid insulation section, which, in conjunction with the inner wall of the insulating sleeve 200, further constrains the air insulation section. The solid insulation section is made of a silicone rubber material with high insulation properties and possesses a strong ability to withstand voltage field strengths. Therefore, after the solid insulation section is subjected to a certain field strength, the field strength per unit length within the air insulation section decreases. By further reducing the pressure per unit length within the air insulation section to within a preset field strength tolerance range, insulation requirements can be met. This eliminates the need to fill the air insulation section with insulating medium, eliminating the risk of dielectric leakage affecting insulation and environmental protection. Furthermore, compared to filling with insulating oil, the air insulation section is lighter, making it easier to transport and install.

[0021] If the air-insulated section's per-unit-length electric field strength falls within the preset field strength tolerance range, the insulation requirements can be met. Theoretically, the preset field strength tolerance range can have no lower limit, meaning the air-insulated section's per-unit-length electric field strength can be infinitely small. However, considering the terminal's overall weight, manufacturing cost, and portability for transportation and installation, it needs to be limited to a reasonable range. It should be noted that the upper limit of the preset field strength tolerance range needs to be less than the air breakdown electric field strength of 3000V / mm to avoid air breakdown.

[0022] The above-mentioned preset field strength tolerance range is affected by the working voltage level of the power cable terminal. Generally, for products with higher working voltage levels, although the height increases, it is far less than the increase in voltage level. At this time, the field strength per unit length will also increase accordingly. Correspondingly, in order to take into account the overall weight, manufacturing cost, portability of transportation and installation and other conditions, the preset field strength tolerance range will also be adaptively adjusted. It is usually set that the numerical value range corresponding to the preset field strength tolerance range is positively correlated with the working voltage level of the power cable terminal.

[0023] The conical shielding cover 500 can be directly fixed to the top of the insulating sleeve 200, thereby forming a seal on the top of the insulating sleeve 200. Moreover, because it adopts a conical design, it can form a semi-enclosure of the tip of the cable 1000, thereby effectively achieving tip shielding.

[0024] The auxiliary fastener 600 can achieve the connection between the connecting fitting 1100 and the conical shielding cover 500 , thereby fixing the cable 1000 and also completing the sealing of the top of the conical shielding cover 500 .

[0025] The insulating material of the annular rubber cone 250 and the stress control cone 400 is composed of components AB with a ratio of 9:1 or 1:1. The kinematic viscosity of the product mixture is 10,000 mPa.s. The material parameters after formation must meet the following requirements: Density: 1.1-1.13g / cm 3 ; Tear strength: 20-25N / mm; Shore hardness: Shore A30~36; Elongation at break: ≥400%; Breakdown strength: ≥20kV / mm; Dielectric loss: ≤0.001.

[0026] In some embodiments, when the working voltage level of the power cable terminal is 110KV, the preset field strength tolerance range is 150~200V / mm; when the working voltage level of the power cable terminal is 150KV, the preset field strength tolerance range is 200~300V / mm; when the working voltage level of the power cable terminal is 220KV, the preset field strength tolerance range is 300~400V / mm.

[0027] When the operating voltage level of the above-mentioned power cable terminal is 110kV, the preset field strength tolerance range is 150~200V / mm. It can be understood that for a 110kV terminal, the field strength per unit length of the air-insulated section can reach 150~200V / mm, which can achieve the insulation performance of traditional insulating oil or insulating gas-filled products. At the same time, it can be superior to the two traditional products in terms of weight, environmental friendliness, and maintenance requirements. It should be noted that when the threshold value of 200V / mm is selected, although the field strength per unit length increases, the length of the solid insulation section can be effectively shortened, thereby enabling the design of a lighter terminal product. Therefore, in actual production, the field strength per unit length selected will be as close to 200V / mm as possible, for example, 170V / mm, 180V / mm, 190V / mm, etc.

[0028] When the operating voltage level of the above-mentioned power cable terminal is 150kV, the preset field strength tolerance range is 200~300V / mm. It can be understood that for a 150kV terminal, the field strength per unit length of the air-insulated section can reach 200~300V / mm, which can achieve the insulation performance of traditional insulating oil or insulating gas-filled products. At the same time, it can be superior to the two traditional products in terms of weight, environmental friendliness, and maintenance requirements. It should be noted that when the threshold value of 300V / mm is selected, although the field strength per unit length increases, the length of the solid insulation section can be effectively shortened, thereby enabling the design of a lighter terminal product. Therefore, in actual production, the field strength per unit length selected will be as close to 300V / mm as possible, for example, 270V / mm, 280V / mm, 290V / mm, etc.

[0029] When the operating voltage level of the above-mentioned power cable terminal is 220kV, the preset field strength tolerance range is 300~400V / mm. It can be understood that for a 220kV terminal, the field strength per unit length of the air-insulated section can reach 300~400V / mm, which can achieve the insulation performance of traditional insulating oil or insulating gas-filled products. At the same time, it can be superior to the two traditional products in terms of weight, environmental friendliness, and maintenance requirements. It should be noted that when the threshold value of 400V / mm is selected, although the field strength per unit length increases, the length of the solid insulation section can be effectively shortened, thereby enabling the design of a lighter terminal product. Therefore, in actual production, the field strength per unit length selected will be as close to 400V / mm as possible, for example, 370V / mm, 380V / mm, 390V / mm, etc.

[0030] It should be noted that, according to the structural arrangement in the embodiment of the present application, the field strength of the air-insulated section in the horizontal direction of the surface is substantially the same as that in the vertical direction.

[0031] In some embodiments, the preset field strength tolerance range is determined by the following steps: Determine the electric field strength per unit length of the solid insulation section in the height direction; Determine the preset field strength tolerance range based on the electric field strength that the solid can withstand, the length of the solid insulation section, and the working voltage level of the power cable terminal; Among them, the working voltage level of the terminal for the power cable is used to determine the total borne field strength, and the sum of the borne field strength of the solid insulation section and the borne field strength of the air insulation section meets the total borne field strength; when the borne field strength of the solid insulation section per unit length remains unchanged, the length of the solid insulation section is negatively correlated with the numerical value range corresponding to the preset field strength tolerance range; when the length of the solid insulation section remains unchanged, the borne field strength of the solid insulation section per unit length is negatively correlated with the numerical value range corresponding to the preset field strength tolerance range; among them, the preset field strength tolerance range must be less than the air breakdown voltage.

[0032] The electric field strength per unit length of the solid insulating section in the height direction can be directly confirmed through experiments, simulations or theoretical calculations after the terminal structure and materials are finalized.

[0033] Once the operating voltage level of the power cable terminal is determined, the total electric field strength the terminal must withstand is known. The terminal can meet insulation requirements by ensuring that the sum of the field strengths that the solid-insulated and air-insulated sections can withstand exceeds the total electric field strength.

[0034] The above-mentioned solid insulation section per unit length is subjected to a constant electric field strength, which can be understood as the material properties constituting the solid insulation section being constant. Taking silicone rubber as an example, the insulating capacity of silicone rubber is greater than that of air. Therefore, the electric field strength per unit length of the solid insulation section is usually greater than the electric field strength per unit length of the air insulation section. At this time, when the solid insulation section is increased by a fixed length on the basic length, although the air insulation section will be shortened, the electric field strength per unit length will be less shared because the field strength borne by the solid insulation section increases more.

[0035] The length of the above-mentioned solid insulation section remains unchanged, but the field strength per unit length of the solid insulation section changes, which can be understood as a change in the material properties of the solid insulation section. Taking different types of silicone rubber, rubber, etc. as an example, there are certain differences in insulation properties between different materials. Therefore, even if the length of the solid insulation section remains unchanged, the field strength shared by the solid insulation section will change. It can be understood that the better the insulation performance of the material, the greater the shared field strength. Accordingly, the field strength shared by the air insulation section can be reduced, and the field strength shared per unit length will also decrease, thereby making the preset field strength tolerance range can be set smaller. Conversely, the worse the insulation performance of the material, the less the shared field strength. Accordingly, the field strength shared by the air insulation section needs to be increased, and the field strength shared per unit length will also increase, thereby making the preset field strength tolerance range set larger accordingly.

[0036] It is understandable that the parameter of the preset field strength tolerance range will be affected by both the electric field strength that the solid can withstand and the length of the solid insulating section. Therefore, in actual operation, a more reasonable preset field strength tolerance range can be obtained by flexibly adjusting the two parameters of the electric field strength that the solid can withstand and the length of the solid insulating section, or by conducting a limited number of experiments.

[0037] Furthermore, the insulation properties of mainstream or cutting-edge materials used to form solid insulation sections are generally uniform across the market. Consequently, in most scenarios, the primary consideration is the impact of the solid insulation section's length on the preset field strength tolerance range. Conversely, by setting an appropriate preset field strength tolerance range, the length of the solid insulation section can also be limited to a reasonable range.

[0038] In some embodiments, reference Figure 1 The connecting conductor at the top of the cable 1000 for connecting to the connecting fitting 1100 is located above the insulating sleeve 200 and is surrounded by the conical shielding cover 500.

[0039] In this embodiment, by positioning the connecting conductor of the connecting fitting 1100 above the insulating sleeve 200, the conical shielding cover 500 can better surround the cable 1000. At the same time, the influence of the conductor on the electric field distribution when it is set in the insulating sleeve 200 can be reduced, so that the terminal for the power cable filled with normal pressure air 1200 can operate more stably.

[0040] In some embodiments, the hardness difference between the annular rubber cone 250 and the stress control cone 400 is 25HA to 35HA.

[0041] In this embodiment, this hardness difference setting can improve the interface sealing reliability and uniform stress dispersion between the two, while reducing structural loss and failure risks in long-term operation, providing a key guarantee for the stable operation of the atmospheric pressure air 1200 insulation terminal.

[0042] In some embodiments, reference Figure 1 、 Figure 2 , insulating sleeve 200, including: The support tube 210 has its bottom end mounted on the base 100 ; an annular rubber cone 250 is prefabricated in the support tube 210 ; The upper flange 220 is provided on the top of the support tube 210 and is used to connect the conical shield 500; The silicone rubber sheds 230 include large sheds and small sheds alternately arranged on the outer surface of the support tube 210; The lower flange 240 is disposed at the bottom of the support tube 210 and is used to connect to the base 100 .

[0043] The support tube 210 may be made of rubber or glass fiber impregnated with epoxy resin, so that the support tube 210 has a high strength, thereby enabling the flexible power terminal to achieve self-support.

[0044] The annular rubber cone 250 is bonded to the inner wall of the support tube 210 by using an AB component adhesive.

[0045] The upper flange 220 can be connected to the conical shielding cover 500 , thereby achieving sealing of the top of the support tube 210 .

[0046] The lower flange 240 can be connected to the base 100 , thereby sealing the bottom of the support tube 210 .

[0047] The silicone rubber sheds 230 are composed of large sheds and small sheds alternately arranged on the outer surface of the support tube 210. This alternating arrangement can greatly improve the external creepage distance of the power cable terminal.

[0048] In some embodiments, the insulating sleeve 200 is obtained by the following steps: The support tube 210, the upper flange 220, the silicone rubber shed 230, and the lower flange 240 are preformed to obtain the sleeve body; Applying silicone epoxy resin adhesive to the inner wall of the sleeve body to complete the bonding between the prefabricated annular rubber cone 250 and the inner wall of the sleeve; An annular rubber cone 250 is prefabricated inside the sleeve body, and a special mold is used to form the air insulation section and the second through hole of the annular rubber cone 250, and then vulcanization treatment is performed; the entirety formed by the annular rubber cone 250 and the sleeve body is vulcanized to obtain the insulating sleeve 200.

[0049] In this embodiment, the insulating sleeve 200 is obtained by first forming the sleeve body, and then forming the annular rubber cone 250 on the sleeve body using a dedicated mold. This method allows the annular rubber cone 250 to be formed on the sleeve body in one step, eliminating the need to glue the formed annular rubber cone 250 to the insulating sleeve 200. It should be noted that after the annular rubber cone 250 is molded onto the inner wall of the sleeve body, it is necessary to pre-form the annular rubber cone 250 on the sleeve body using a dedicated mold and perform a secondary vulcanization process to ensure the structural strength and integrity of the resulting insulating sleeve 200.

[0050] In some embodiments, the insulating sleeve 200 is obtained by the following steps: The support tube 210, the upper flange 220, the silicone rubber shed 230, and the lower flange 240 are preformed to obtain the sleeve body; The outer shape of the preformed annular rubber cone 250 and the second through hole are completed on the equipment using a special mold, and then vulcanized; Apply silicone epoxy resin adhesive to the inner wall of the sleeve body; Place the sealing mold and the annular rubber cone 250 into the support tube 210. The sealing mold is used to determine the size of the air insulation section in the sleeve body and ensure that the outer surface of the annular rubber cone 250 is perfectly bonded to the inner wall of the sleeve body. The annular rubber cone 250 and the sleeve body are integrally formed by vulcanization molding to obtain the insulating sleeve 200.

[0051] In this embodiment, the annular rubber cone 250 and the tube sleeve body are first prefabricated and formed separately, and then the annular rubber cone 250 is glued to the tube sleeve body. In this way, the annular rubber cone 250 and the tube sleeve body can be formed separately, without the need to form the annular rubber cone 250 on the tube sleeve body after the tube sleeve body is formed.

[0052] It should be noted that after the annular rubber cone 250 is injection molded, it also needs to be vulcanized to improve the overall structural strength and integrity of the insulating sleeve 200. In some embodiments, the silicone epoxy resin adhesive is divided into component A and component B. The platinum content of component B is 30 ppm, and the Brookfield viscosity of component A is 2500 mPa.s.

[0053] In this embodiment, such an arrangement can ensure that the bonding ability of the silicone epoxy resin adhesive meets the bonding requirements while also having good insulation performance.

[0054] In some embodiments, parameters such as the size and position of the large and small sheds, the minimum distance between sheds, the creepage distance between the large sheds, and the total dry arc distance are all within the design range without deviation and meet the design requirements.

[0055] In some embodiments, the external creepage distance of the power cable terminal is greater than or equal to 38 kV / mm.

[0056] The external creepage distance of the above-mentioned power cable terminal is greater than or equal to 38KV / mm, which is better than the requirement for the external creepage distance of the power cable terminal and basically meets the needs of all common terminal products on the market.

[0057] In some embodiments, the annular rubber cone 250 is pre-bonded to the inner wall of the support tube 210 using an AB component adhesive.

[0058] In the above-mentioned AB component adhesive, the platinum content in component B is 30 ppm, and the Brookfield viscosity of component A is 2500 mPa.s.

[0059] In some embodiments, reference Figure 1 The above-mentioned power cable terminal further includes: The rain cover 700 is disposed on the conical shielding cover 500 and surrounds the conical shielding cover 500 .

[0060] In this embodiment, the provision of the rain cover 700 can provide an effective rainproof function and reduce the impact of rain on the terminal.

[0061] In some embodiments, reference Figure 1 、 Figure 4 , the auxiliary fastener 600, comprising: The tightening ring 610 is provided on the conical shielding cover 500 and sleeved on the connecting hardware 1100, and is used to connect the connecting hardware 1100 and the conical shielding cover 500; The gland 620 is sleeved on the connection fitting 1100 and fixed on the tightening ring 610 via nuts arranged along the radial direction of the cable 1000 .

[0062] In this embodiment, the conical shielding cover 500 can be better pressed onto the upper flange 220 by using the pressing cover 620 , and the connection and sealing between the multiple components can be better achieved by using the tightening ring 610 .

[0063] In some embodiments, reference Figure 1 The above-mentioned power cable terminal further includes: The support insulator 800 is provided on the base 100 and is used to place the terminal of the power cable on the cable support.

[0064] In this embodiment, the use of the support insulator 800 can better realize the installation and arrangement of the terminal for the power cable.

[0065] In some embodiments, reference Figure 1 , terminals for power cables, further comprising: The tail grounding sealing tube 900 is sleeved on the cable 1000 and located below the base 100 to form a seal on the bottom of the base 100 .

[0066] In this embodiment, the tail grounding sealing tube 900 is used to seal the bottom of the base 100, so that an extremely closed space can be formed in the insulating tube sleeve 200, reducing the impact of external substances and environment on the interior.

[0067] like Figure 5 , which is a flow chart of a method for manufacturing a terminal for a power cable also proposed in an embodiment of the present application, the method for manufacturing a terminal for a power cable includes steps S100 to S800.

[0068] In step S100 , the cable 1000 is passed through the first through hole of the base 100 , and the cable 1000 is pre-processed to expose the connecting conductor.

[0069] In step S200 , the cable 1000 is passed through the third through hole of the supporting rubber member 300 , and the supporting rubber member 300 is fixed to the base 100 .

[0070] In step S300 , the cable 1000 is passed through the fourth through hole of the stress control cone 400 , and the stress control cone 400 is pushed down until it comes into contact with the supporting rubber member 300 with a pressing force.

[0071] Step S400 : Connect the connecting fitting 1100 to the connecting conductor of the cable 1000 .

[0072] Step S500: Pass the cable 1000 through the second through hole of the insulating sleeve 200, and push the insulating sleeve 200 down until it is in compressive contact with the stress control cone 400; wherein, an annular rubber cone 250 is prefabricated in the insulating sleeve 200; the annular rubber cone 250 has a second through hole, and the aperture of the second through hole at the end away from the base 100 is smaller than the aperture at the end close to the base 100; in the insulating sleeve 200, above the top of the annular rubber cone 250 and the stress control cone 400 is an air insulation section, and below the top is a solid insulation section, and the air insulation section is filled with normal pressure air 1200; the electric field strength per unit length of air in the height direction of the air insulation section is within a preset field strength tolerance range, wherein the numerical value of the value range corresponding to the preset field strength tolerance range is positively correlated with the working voltage level of the terminal for the power cable; Step S600, fixing the bottom end of the insulating sleeve 200 to the base 100; Step S700: insert the connecting fitting 1100 through the fifth through hole of the conical shielding cover 500 and fix the conical shielding cover 500 to the top end of the insulating sleeve 200; In step S800 , the auxiliary fastener 600 is used to seal the top of the conical shielding cover 500 .

[0073] In this embodiment, the assembly of the power cable terminal can be completed by assembly, and the assembly process does not require the use of adhesives or other long-term waiting processes to assemble the terminal interior. Assembly can be completed using only assembly parts, thereby greatly improving the installation efficiency of the cable 1000 terminal. Moreover, because the assembly process is adopted, each component can be prefabricated in advance, eliminating the need for a large amount of time to wait between each link due to the correlation, thereby greatly improving production efficiency. In addition, the power cable terminal assembled in this embodiment has been described above, and it also has all the beneficial effects of the aforementioned power cable terminal.

[0074] The above-mentioned cable 1000 pretreatment can be understood as stripping the connecting part of the cable 1000 to expose the insulation layer, semi-conductive layer, connecting conductor and other structures, and presenting a stepped arrangement. The specific amount of each part leaked can be determined according to the wiring process of the terminal to be connected, and will not be repeated here.

[0075] The pre-treatment of the cable 1000 also includes heating and straightening the cable 1000. The straightened cable 1000 can be more convenient for assembly operation.

[0076] After the supporting rubber member 300 is fixed to the base 100 , the semi-conductive stress control member 410 in the stress control cone 400 subsequently provided thereon needs to be flush with the end of the semi-conductive layer of the cable 1000 .

[0077] A step structure may be provided at the contact point between the stress control cone 400 and the supporting rubber member 300 , so that the supporting rubber member 300 can better assist the stress control cone 400 in completing position definition.

[0078] In the process of pushing the insulating sleeve 200 down to fit tightly against the stress control cone 400 , the supporting rubber member 300 has been installed in advance, so the annular rubber cone 250 and the supporting rubber member 300 can jointly limit the spatial position of the stress control cone 400 .

[0079] The above-mentioned fixing of the bottom end of the insulating sleeve 200 to the base 100 can be completed by bolt fasteners.

[0080] The above-mentioned fixing of the conical shielding cover 500 to the top end of the insulating sleeve 200 can be completed by bolt fasteners.

[0081] The use of the auxiliary fastener 600 to seal the top end of the conical shielding cover 500 may be accomplished by bolt fasteners.

[0082] It should be noted that, for the parts that need to be sealed, a sealing groove and a sealing ring matching connection structure can be provided to improve the sealing performance.

[0083] In some embodiments, before passing the cable 1000 through the first through hole of the base 100, the method further includes: Sleeve the tail grounding sealing tube 900 onto the cable 1000; After the auxiliary fastener 600 is used to seal the top end of the conical shield 500, the method further includes: The tail grounding sealing tube 900 is fixed on the base 100 , and a lead welding rod is used to complete the sealing between the tail grounding sealing tube 900 and the metal sheath layer of the cable 1000 .

[0084] In this embodiment, in order to achieve sealing between the base 100 and the cable 1000, the tail sealing tube will be installed before the base 100 is installed. After the main body of the terminal is assembled, the tail sealing tube can be used to effectively seal the bottom of the base 100, thereby improving the sealing effect of the entire terminal.

[0085] In some embodiments, before passing the cable 1000 through the first through hole of the base 100, the method further includes: Install the support insulator 800 on the cable support; The base 100 is fixed on the supporting insulator 800 .

[0086] In this embodiment, the support insulator 800 is used to preferentially secure the base 100 , thereby providing a stable foundation for the subsequent installation of the terminal body.

[0087] In some embodiments, the support insulator 800 and the base 100 are fixed after the tail grounding sealing tube 900 is sleeved on the cable 1000 .

[0088] In some embodiments, after the auxiliary fastener 600 is used to form a seal on the top end of the conical shield 500, the method further includes: A rain cover 700 is mounted on the surface of the conical shielding cover 500 to complete the top seal.

[0089] In this embodiment, the rain cover 700 can provide effective rain protection and reduce the impact of rain on the terminal. In addition, the rain cover 700 is the outermost structure and can be installed after the main structure is completed.

[0090] The embodiments of the present application are described in detail above in conjunction with the accompanying drawings, but the present application is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the purpose of the present application.

Claims

1. A terminal for a power cable, characterized in that: include: The base has a first through hole for the cable to pass through; the top end of the cable is connected to a connecting hardware; An insulating sleeve, the bottom end of which is connected to the base, wherein an annular rubber cone is prefabricated in the insulating sleeve; a second through hole is formed in the annular rubber cone, and the aperture of the second through hole at the end away from the base is smaller than the aperture at the end close to the base; a supporting rubber member, disposed on the base and located in the second through hole, the supporting rubber member having a third through hole for the cable to pass through; A stress control cone having a fourth through hole for the cable to pass through; the stress control cone is supported by the supporting rubber member so that the outer surface of the stress control cone is in contact with the inner surface of the second through hole; within the insulating sleeve, the annular rubber cone and the stress control cone are above the top of the air insulation section, and the solid insulation section is below the top, and the air insulation section is filled with air at normal pressure; the electric field strength per unit length of air in the height direction of the air insulation section is within a preset field strength tolerance range, wherein the numerical value of the value range corresponding to the preset field strength tolerance range is positively correlated with the operating voltage level of the power cable terminal; a conical shielding cover having a fifth through hole for the connecting fitting to pass through, wherein the bottom end of the conical shielding cover is connected to the top of the insulating sleeve and forms a seal with the top of the insulating sleeve; An auxiliary fastener is used to connect the connecting hardware and the conical shielding cover and to form a seal on the top end of the conical shielding cover.

2. The power cable terminal according to claim 1, characterized in that: When the working voltage level of the power cable terminal is 110KV, the preset field strength tolerance range is 150~200V / mm; when the working voltage level of the power cable terminal is 150KV, the preset field strength tolerance range is 200~300V / mm; when the working voltage level of the power cable terminal is 220KV, the preset field strength tolerance range is 300~400V / mm.

3. The power cable terminal according to claim 2, characterized in that: The connecting conductor at the top end of the cable, which is used to connect to the connecting hardware, is located above the insulating sleeve and is surrounded by the conical shielding cover.

4. The power cable terminal according to claim 1, characterized in that: The insulating sleeve comprises: A support tube, the bottom end of which is arranged on the base; the annular rubber cone is prefabricated in the support tube; an upper flange, provided on the top of the support tube, for connecting the conical shield; Silicone rubber sheds, comprising large sheds and small sheds alternately arranged on the outer surface of the support tube; The lower flange is arranged at the bottom of the support tube and is used for connecting to the base.

5. The power cable terminal according to claim 1, characterized in that: Also includes: The rainproof cover is arranged on the conical shielding cover and surrounds the conical shielding cover.

6. The power cable terminal according to claim 1, characterized in that: The auxiliary fastener comprises: A tightening ring, provided on the conical shielding cover and sleeved on the connecting hardware, for connecting the connecting hardware and the conical shielding cover; The gland is sleeved on the connecting fitting and fixed on the tightening ring through nuts arranged along the radial direction of the cable.

7. The power cable terminal according to claim 1, characterized in that: Also includes: A supporting insulator is provided on the base and is used for arranging the terminal of the power cable on the cable support.

8. The power cable terminal according to claim 1, characterized in that: Also includes: The tail grounding sealing tube is sleeved on the cable and located below the base, and is used to form a seal on the bottom of the base.

9. A method for manufacturing a terminal for a power cable, characterized in that: include: Passing the cable through the first through hole of the base, wherein the cable is pre-processed to expose the connecting conductor; Passing the cable through the third through hole of the supporting rubber member, and fixing the supporting rubber member to the base; Passing the cable through the fourth through hole of the stress control cone, and pushing the stress control cone downward until it contacts the supporting rubber member with a pressing force; Connecting the connecting fitting to the connecting conductor of the cable; The cable is passed through the second through hole of the insulating sleeve, and the insulating sleeve is pushed down until it is in compression contact with the stress control cone; wherein, an annular rubber cone is prefabricated in the insulating sleeve; the annular rubber cone has the second through hole, and the aperture of the second through hole at the end away from the base is smaller than the aperture at the end close to the base; in the insulating sleeve, the area above the top of the annular rubber cone and the stress control cone is an air insulation section, and the area below the top is a solid insulation section, and the air insulation section is filled with air at normal pressure; the electric field strength per unit length of air in the height direction of the air insulation section is within a preset field strength tolerance range, wherein the numerical value of the value range corresponding to the preset field strength tolerance range is positively correlated with the working voltage level of the terminal for the power cable; Fixing the bottom end of the insulating sleeve to the base; Passing the connecting hardware through the fifth through-hole of the conical shielding cover, and fixing the conical shielding cover to the top end of the insulating sleeve; A secondary fastener is used to form a seal on the top end of the conical shield.

10. The method for manufacturing a power cable terminal according to claim 9, wherein: Before passing the cable through the first through hole of the base, the method further includes: Sleeving the tail grounding sealing tube on the cable; After the auxiliary fastener is used to form a seal on the top end of the conical shield, the method further comprises: The tail grounding sealing tube is fixed on the base, and a lead welding rod is used to complete the sealing between the tail grounding sealing tube and the metal sheath layer of the cable.

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