Terminal for power cable and method of manufacturing the same

Abstract

This application discloses a terminal for power cables and its manufacturing method. By rationally setting stress control cones and annular rubber cones, the epoxy sheath is divided into air insulation and solid insulation sections. Furthermore, based on the working voltage level of the power cable terminal, the electric field strength per unit length of the air insulation section is rationally configured, so that the air insulation section only needs to be filled with atmospheric pressure air to meet the insulation requirements, without relying on insulating gas or oil to enhance the insulation strength of the gas part of the terminal. Moreover, using atmospheric pressure air filling can effectively reduce the sealing requirements of the terminal and eliminate concerns about environmental pollution caused by leakage of insulating medium. At the same time, by setting a conical shield, the top of the epoxy sheath can be directly sealed and the discharge shielding of the cable tip can be achieved, further ensuring the overall function of the atmospheric pressure air power cable terminal. In addition, this terminal uses atmospheric pressure air insulation, which does not require medium filling, and is easy to complete the assembly manufacturing by prefabrication.

Description

Technical Field

[0001] This application relates to the field of cable terminations, and in particular to a termination for power cables and a method for manufacturing the same. Background Technology

[0002] Early power cable terminals mostly used oil-immersed or SF6 gas insulation, which posed leakage risks and did not meet environmental protection requirements. For example, gas-insulated transmission lines rely on SF6 gas, but its greenhouse effect potential is as high as 23,500 times that of CO2, and leakage risks pose a threat to the ecological environment. At the same time, oil-immersed insulation structures also pose leakage pollution risks and are difficult to meet the requirements for green power grid construction. Summary of the Invention

[0003] This application aims to address at least one of the technical problems existing in the prior art. To this end, this application proposes a terminal for power cables and a method for manufacturing the same, which can directly use air as the insulating medium, thereby solving the problems of environmental pollution and failure to meet insulation requirements caused by leakage of the filling medium in traditional terminals.

[0004] A terminal for a power cable according to a first aspect embodiment of this application includes:

[0005] The base has a first through hole for the cable to pass through; the top end of the cable is connected to a connecting fitting;

[0006] An insulating sleeve has its bottom end connected to the base. An annular rubber cone is prefabricated inside the insulating sleeve. The annular rubber cone has a second through hole, and the diameter of the second through hole at the end away from the base is smaller than the diameter at the end closer to the base.

[0007] A supporting rubber component is disposed on the base and located within the second through hole, and the supporting rubber component has a third through hole for cable to pass through;

[0008] A stress control cone has a fourth through hole for the cable to pass through; the stress control cone is supported by the supporting rubber component, such that the outer surface of the stress control cone is in contact with the inner surface of the second through hole; inside the insulating sleeve, the annular rubber cone and the stress control cone are in an air insulation section above the top and a solid insulation section below the top, the air insulation section being filled with atmospheric pressure air; the air insulation section withstands an electric field strength per unit length in the height direction within a preset field strength tolerance range, wherein the value range corresponding to the preset field strength tolerance range is positively correlated with the operating voltage level of the power cable terminal;

[0009] A conical shield has a fifth through hole for the connecting hardware to pass through, and the bottom end of the conical shield is connected to the top of the insulating sleeve and forms a seal on the top of the insulating sleeve.

[0010] An auxiliary fastener is used to connect the connecting hardware and the conical shield, and to form a seal on the top of the conical shield.

[0011] A method for manufacturing a terminal for a power cable according to a second aspect embodiment of this application includes:

[0012] The cable is threaded through the first through hole in the base, and the cable is pre-treated to expose the connecting conductor;

[0013] The cable is threaded through the third through hole of the supporting rubber component, and the supporting rubber component is fixed to the base;

[0014] The cable is passed through the fourth through hole of the stress control cone, and the stress control cone is pushed down until it contacts the supporting rubber component with a certain clamping force;

[0015] Connect the connecting hardware to the connecting conductor of the cable;

[0016] 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 inside the insulating sleeve; the annular rubber cone has the second through hole, the diameter of the second through hole at the end away from the base is smaller than the diameter at the end closer to the base; inside 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, the air insulation section is filled with atmospheric pressure air; the electric field strength per unit length of the air insulation section in the height direction is within a preset field strength tolerance range, wherein the value range corresponding to the preset field strength tolerance range is positively correlated with the working voltage level of the power cable terminal;

[0017] Fix the bottom end of the insulating sleeve to the base;

[0018] The connecting hardware is inserted through the fifth through hole of the conical shield and the conical shield is fixed to the top of the insulating sleeve;

[0019] The top of the conical shield is sealed using auxiliary fasteners.

[0020] The power cable terminal and its manufacturing method according to this application embodiment, by reasonably setting stress control cones and annular rubber cones, divides the epoxy sheath into air insulation sections and solid insulation sections. Furthermore, based on the working voltage level of the power cable terminal, the electric field strength per unit length of the air insulation section is reasonably configured, so that the air insulation section only needs to be filled with atmospheric pressure air to meet the insulation requirements, without relying on insulating gas or oil to enhance the insulation strength of the gas portion of the terminal. Using atmospheric pressure air effectively reduces the sealing requirements of the terminal and eliminates concerns about environmental pollution caused by leakage of the insulating medium. Simultaneously, by setting a conical shield, the top of the epoxy sheath can be directly sealed and the cable tip discharge shielded, further ensuring the overall function of the atmospheric pressure air power cable terminal. In addition, this terminal uses atmospheric pressure air insulation, eliminating the need for medium filling, facilitating prefabrication and assembly, significantly improving manufacturing and installation convenience, and making it more suitable for use in time-critical scenarios such as emergency repairs.

[0021] Other features and advantages of this application will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing this application. Attached Figure Description

[0022] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0023] Figure 1 This is a schematic diagram of the structure of a power cable terminal according to an embodiment of this application;

[0024] Figure 2 This is a schematic diagram of the structure of the insulating sleeve according to an embodiment of this application;

[0025] Figure 3 This is a schematic diagram of the stress control cone according to an embodiment of this application;

[0026] Figure 4 for Figure 1 A magnified view of the top;

[0027] Figure 5 This is a flowchart of a method for manufacturing a terminal for a power cable according to an embodiment of this application.

[0028] Icon labels:

[0029] Base 100; Insulating sleeve 200; Support tube 210; Upper flange 220; Silicone rubber umbrella skirt 230; Lower flange 240; Annular rubber cone 250; Supporting rubber component 300; Stress control cone 400; Semi-conductive stress control component 410; Conical shield 500; Auxiliary fastener 600; Tightening ring 610; Pressure cap 620; Rain cover 700; Supporting insulator 800; Tail grounding sealing pipe 900; Cable 1000; Connecting hardware 1100; Atmospheric pressure air 1200. Detailed Implementation

[0030] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0031] In the description of this application, it should be understood that the orientation descriptions, such as 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, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0032] In the description of this application, "multiple" refers to two or more. The use of "first" and "second" is for the purpose of distinguishing technical features only and should not be construed as indicating or implying relative importance, or implicitly indicating the number of technical features indicated, or the order in which the technical features are indicated.

[0033] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.

[0034] refer to Figures 1 to 4 This application discloses a power cable terminal, which includes:

[0035] The base 100 has a first through hole for the cable 1000 to pass through; the top end of the cable 1000 is connected to a connecting hardware 1100;

[0036] An insulating sleeve 200 is connected at its bottom end to a base 100. An annular rubber cone 250 is prefabricated inside the insulating sleeve 200. The annular rubber cone 250 has a second through hole, and the diameter of the second through hole at the end away from the base 100 is smaller than the diameter at the end closer to the base 100.

[0037] A supporting rubber component 300 is disposed on the base 100 and located in the second through hole. The supporting rubber component 300 has a third through hole for the cable 1000 to pass through.

[0038] 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 component 300, so that the outer surface of the stress control cone 400 is in contact with the inner surface of the second through hole; inside the insulating sleeve 200, the annular rubber cone 250 and the top of the stress control cone 400 are air insulation sections, and the bottom is a solid insulation section, and the air insulation section is filled with atmospheric pressure air 1200; the electric field strength per unit length of the air insulation section in the height direction is within the preset field strength tolerance range, wherein the value range corresponding to the preset field strength tolerance range is positively correlated with the working voltage level of the power cable terminal;

[0039] The conical shield 500 has a fifth through hole for the connecting hardware 1100 to pass through. The bottom end of the conical shield 500 is connected to the top of the insulating sleeve 200 and forms a seal on the top of the insulating sleeve 200.

[0040] The auxiliary fastener 600 is used to connect the connecting hardware 1100 and the conical shield 500, and to form a seal on the top of the conical shield 500.

[0041] In this embodiment, by rationally setting the stress control cone 400 and the annular rubber cone 250, the epoxy tubing is divided into an air insulation section and a solid insulation section. Furthermore, based on the working voltage level of the power cable terminal, the electric field strength per unit length of the air insulation section is rationally configured, allowing the air insulation section to meet insulation requirements simply by filling it with atmospheric pressure air 1200, eliminating the need to rely on insulating gas or oil to enhance the insulation strength of the gas portion of the terminal. Using atmospheric pressure air 1200 effectively reduces the sealing requirements of the terminal and eliminates concerns about environmental pollution caused by leakage of the insulating medium. Simultaneously, by setting the conical shield 500, the top of the epoxy tubing and the tip discharge shielding of the cable 1000 can be directly achieved, further ensuring the overall function of the atmospheric pressure air 1200 power cable terminal. In addition, this terminal utilizes atmospheric pressure air 1200 insulation, eliminating the need for medium filling, facilitating prefabrication and assembly, significantly improving manufacturing and installation convenience, and making it more suitable for use in time-critical scenarios such as emergency repairs. Furthermore, leakage of insulating oil can easily cause combustion and explosion, posing a significant safety risk. When using insulating gas for filling, high-pressure gas is required, which makes the insulating terminals prone to explosion due to high pressure, also posing a significant safety risk.

[0042] The aforementioned insulating sleeve 200 has a pre-fabricated annular rubber cone 250, which can be prefabricated by bonding. Specifically, it can be bonded using an AB component adhesive.

[0043] The aforementioned annular rubber cone 250 can be a high-hardness, environmentally friendly rubber cone.

[0044] The aforementioned supporting rubber component 300 is used to support the stress control cone 400, so that after the power cable terminal is installed, the semi-conductive stress control component 410 inside the stress control cone 400 can be flush with the port of the semi-conductive layer of the cable 1000. It also allows the stress control cone 400 to fit tightly against the inner wall of the annular rubber cone 250 without the need for adhesive bonding.

[0045] The inner wall of the aforementioned annular rubber cone 250 is arranged in a conical slope, and the outer surface of the stress control cone 400 is arranged in a conical slope that adapts to the inner wall of the annular rubber cone 250. After the aforementioned supporting rubber component 300 supports the stress control cone 400 in place, it 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 form regular solid insulation sections and air insulation sections in the future.

[0046] The aforementioned stress control cone 400 and annular rubber cone 250 form a solid insulation section, which, together with the inner wall of the insulating sleeve 200, further constrains the air insulation section. The solid insulation section is made of silicone rubber material with high insulation capacity, possessing an extremely strong ability to withstand voltage field strength. Therefore, after the solid insulation section withstands a certain field strength, the field strength per unit length within the air insulation section can decrease. Furthermore, by reducing the pressure per unit length within the air insulation section to 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 concerns about medium leakage affecting insulation and environmental protection. Moreover, compared to filling with insulating oil, it also has a lighter weight, facilitating transportation and installation.

[0047] If the electric field strength that a unit length of the air-insulated section can withstand falls within the preset electric field strength tolerance range, the insulation requirements can be met. Theoretically, the preset electric field strength tolerance range can have no lower limit, meaning the electric field strength that a unit length can withstand can be infinitely small. However, considering the overall weight of the terminal, manufacturing costs, 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 electric field strength tolerance range needs to be less than the air breakdown electric field strength of 3000V / mm to avoid air breakdown.

[0048] The aforementioned preset field strength withstand range is affected by the working voltage level of the power cable terminal. Generally, for products with higher working voltage levels, although their height is increased, it is far less than the increase in voltage level. At this time, the field strength per unit length will also increase. Correspondingly, in order to take into account the overall weight, manufacturing cost, and portability of transportation and installation, the preset field strength withstand range will be adaptively adjusted. It is usually set that the value range corresponding to the preset field strength withstand range is positively correlated with the working voltage level of the power cable terminal.

[0049] The aforementioned conical shield 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. Furthermore, because it adopts a conical design, it can form a semi-encirclement of the tip of the cable 1000, thereby effectively achieving tip shielding.

[0050] The aforementioned auxiliary fastener 600 can connect the connecting hardware 1100 and the conical shield 500, thereby fixing the cable 1000 and sealing the top of the conical shield 500.

[0051] The insulating material of the aforementioned annular rubber cone 250 and stress control cone 400 is composed of AB components in a ratio of 9:1 or 1:1. The kinematic viscosity of the product mixture is 10000 mPa·s, and the material parameters after formation must meet the following requirements:

[0052] Density: 1.1-1.13 g / cm³ 3 ;

[0053] Tear resistance: 20-25 N / mm;

[0054] Shore hardness: Shore A 30~36;

[0055] Elongation at break: ≥400%;

[0056] Breakdown strength: ≥20kV / mm;

[0057] Dielectric loss: ≤0.001.

[0058] In some implementations, when the operating voltage level of the power cable terminal is 110KV, the preset field strength withstand range is 150~200V / mm; when the operating voltage level of the power cable terminal is 150KV, the preset field strength withstand range is 200~300V / mm; and when the operating voltage level of the power cable terminal is 220KV, the preset field strength withstand range is 300~400V / mm.

[0059] When the operating voltage level of the aforementioned power cable terminals is 110KV, the preset electric field strength withstand range is 150~200V / mm. This means that for a 110KV terminal, the electric field strength withstandd per unit length of air insulation section can reach 150~200V / mm, achieving the insulation performance of traditional oil- or gas-filled insulating products. Furthermore, it surpasses these two types of products in terms of weight, environmental friendliness, and maintenance requirements. It should be noted that while selecting a threshold of 200V / mm increases the electric field strength per unit length, the length of the solid insulation section can be effectively shortened, allowing for the design of lighter terminal products. Therefore, in actual production, the selected electric field strength per unit length will be as close to 200V / mm as possible, such as 170V / mm, 180V / mm, or 190V / mm.

[0060] When the operating voltage level of the aforementioned power cable terminals is 150KV, the preset electric field strength withstand range is 200~300V / mm. This means that for a 150KV terminal, the electric field strength withstandd per unit length of air insulation section can reach 200~300V / mm, achieving the insulation performance of traditional oil- or gas-filled insulating products. Furthermore, it surpasses these two types of products in terms of weight, environmental friendliness, and maintenance requirements. It should be noted that while selecting a threshold of 300V / mm increases the electric field strength per unit length, the length of the solid insulation section can be effectively shortened, allowing for the design of lighter terminal products. Therefore, in actual production, the selected electric field strength per unit length will be as close to 300V / mm as possible, such as 270V / mm, 280V / mm, or 290V / mm.

[0061] When the operating voltage level of the aforementioned power cable terminals is 220KV, the preset electric field strength withstand range is 300~400V / mm. This means that for a 220KV terminal, the electric field strength withstandd per unit length of air insulation section can reach 300~400V / mm, achieving the insulation performance of traditional oil- or gas-filled insulating products. Furthermore, it surpasses these two types of products in terms of weight, environmental friendliness, and maintenance requirements. It should be noted that while selecting a threshold of 400V / mm increases the electric field strength per unit length, the length of the solid insulation section can be effectively shortened, allowing for the design of lighter terminal products. Therefore, in actual production, the selected electric field strength per unit length will be as close to 400V / mm as possible, such as 370V / mm, 380V / mm, or 390V / mm.

[0062] It should be noted that, after the structure is set according to the embodiment of this application, the electric field strength in the horizontal direction of the air insulation section is basically the same as that in the vertical direction.

[0063] In some implementations, the preset field strength tolerance range is determined by the following steps:

[0064] Determine the electric field strength per unit length of the solid insulation section in the height direction;

[0065] The preset electric field strength tolerance range is determined based on the electric field strength borne by the solid, the length of the solid insulation section, and the working voltage level of the power cable terminal.

[0066] The operating voltage level of the power cable terminal is used to determine the total field strength. The sum of the field strength of the solid insulation section and the field strength of the air insulation section must satisfy the total field strength. When the field strength per unit length of the solid insulation section remains constant, the length of the solid insulation section is negatively correlated with the value range corresponding to the preset field strength tolerance range. The preset field strength tolerance range must be less than the air breakdown voltage.

[0067] The electric field strength per unit length of the solid insulation section in the height direction can be directly confirmed through experiments, simulations, or theoretical calculations after the terminal structure and materials are finalized.

[0068] Once the operating voltage level of the aforementioned power cable terminal is determined, the total electric field strength that the entire terminal needs to withstand can be known. The terminal can meet insulation requirements by ensuring that the sum of the electric field strengths that the solid insulation section and the air insulation section can withstand exceeds the total electric field strength.

[0069] The fact that the electric field strength borne by a solid insulation section per unit length remains constant can be understood as the material properties constituting the solid insulation section remaining constant. Taking silicone rubber as an example, silicone rubber has a greater insulating capacity than air. Therefore, the electric field strength borne by a solid insulation section per unit length is usually greater than that borne by an air insulation section per unit length. In this case, when the solid insulation section is increased by a fixed length from the base length, although the air insulation section will be shortened, the electric field strength borne per unit length will be less due to the greater increase in the electric field strength borne by the solid insulation section.

[0070] While the length of the solid insulation section remains constant, the electric field strength borne by each unit length of the solid insulation section changes. This can be understood as a change in the material properties constituting the solid insulation section. Taking different types of silicone rubber and other rubbers as examples, different materials have different insulation properties. Therefore, even if the length of the solid insulation section remains constant, the electric field strength borne by the solid insulation section will change. It can be understood that the better the insulation performance of the material, the more electric field it bears, and correspondingly, the electric field strength borne by the air insulation section can be reduced. This results in a smaller electric field strength per unit length, allowing for a smaller preset electric field strength tolerance range. Conversely, the worse the insulation performance of the material, the less electric field it bears, requiring an increase in the electric field strength borne by the air insulation section. This increases the electric field strength per unit length, allowing for a larger preset electric field strength tolerance range.

[0071] It is understandable that the preset electric field strength tolerance range parameter is affected by both the electric field strength borne by the solid and the length of the solid insulation section. Therefore, in actual operation, a more reasonable preset electric field strength tolerance range can be obtained by flexibly adjusting the two parameters of the electric field strength borne by the solid and the length of the solid insulation section, or by conducting a limited number of experiments.

[0072] Furthermore, for products on the market, the insulation performance of mainstream or cutting-edge materials forming solid insulation sections is generally quite uniform. This means that in most scenarios, the primary consideration is the impact of the solid insulation section's length on the preset electric field strength tolerance range. Conversely, by setting an appropriate preset electric field strength tolerance range, the length of the solid insulation section can also be limited to a reasonable range.

[0073] In some implementations, reference Figure 1 The connecting conductor at the top of the cable 1000, which is used to connect the connecting hardware 1100, is located above the insulating sleeve 200 and is surrounded by the conical shield 500.

[0074] In this embodiment, by placing the connecting conductor of the connecting fitting 1100 above the insulating sleeve 200, the conical shield 500 can better surround the cable 1000, and at the same time, the influence of the conductor being placed inside the insulating sleeve 200 on the electric field distribution can be reduced, which can make the power cable terminal filled with atmospheric pressure air 1200 operate more stably.

[0075] In some embodiments, the hardness difference between the annular rubber cone 250 and the stress control cone 400 is between 25HA and 35HA.

[0076] In this embodiment, this hardness difference setting can improve the interface sealing reliability and stress uniform distribution of the two, while reducing structural damage and failure risk during long-term operation, providing a key guarantee for the stable operation of the atmospheric pressure air 1200 insulation terminal.

[0077] In some implementations, reference Figure 1 , Figure 2 Insulating sleeve 200, including:

[0078] The support tube 210 has its bottom end set on the base 100; a ring-shaped rubber cone 250 is prefabricated inside the support tube 210.

[0079] The upper flange 220 is located at the top of the support tube 210 and is used to connect the conical shield 500;

[0080] The silicone rubber umbrella skirt 230 includes a large umbrella skirt and a small umbrella skirt alternately arranged on the outer surface of the support tube 210;

[0081] The lower flange 240 is located at the bottom of the support tube 210 and is used to connect the base 100.

[0082] The aforementioned support tube 210 can be made of rubber or glass fiber impregnated with epoxy resin, thereby giving the support tube 210 high strength and enabling the flexible power terminal to achieve self-support.

[0083] The aforementioned annular rubber cone 250 is bonded to the inner wall of the support tube 210 using an AB component adhesive.

[0084] The aforementioned upper flange 220 can be connected to the conical shield 500, thereby achieving a seal on the top of the support tube 210.

[0085] The lower flange 240 can be connected to the base 100 to achieve a seal at the bottom of the support tube 210.

[0086] The aforementioned silicone rubber umbrella skirt 230 is composed of large umbrella skirts and small umbrella skirts alternately arranged on the outer surface of the support tube 210. This alternating arrangement can greatly improve the creepage distance of the power cable terminal.

[0087] In some embodiments, the insulating sleeve 200 is obtained through the following steps:

[0088] The support pipe 210, upper flange 220, silicone rubber umbrella skirt 230 and lower flange 240 are prefabricated to obtain the main body of the pipe sleeve;

[0089] Apply silicone epoxy resin adhesive to the inner wall of the sleeve body to complete the bonding between the pre-formed annular rubber cone 250 and the inner wall of the sleeve.

[0090] An annular rubber cone 250 is pre-formed inside the main body of the sleeve. A special mold is used to form the air insulation section and the second through hole of the annular rubber cone 250, and vulcanization is performed. The annular rubber cone 250 and the main body of the sleeve are vulcanized to obtain the insulating sleeve 200.

[0091] In this embodiment, the insulating sleeve 200 is obtained by first forming the main body of the sleeve and then using a special mold to form an annular rubber cone 250 on the main body. This method allows the annular rubber cone 250 to be formed on the main 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 formed to the inner wall of the main body, it is necessary to use a special mold to assemble the pre-formed annular rubber cone 250 on the main body and perform a secondary vulcanization treatment to ensure the structural strength and integrity of the formed insulating sleeve 200.

[0092] In some embodiments, the insulating sleeve 200 is obtained through the following steps:

[0093] The support pipe 210, upper flange 220, silicone rubber umbrella skirt 230 and lower flange 240 are prefabricated to obtain the main body of the pipe sleeve;

[0094] The pre-formed annular rubber cone 250 and the second through hole are completed on the equipment using a special mold, and then vulcanized.

[0095] Apply silicone epoxy resin adhesive to the inner wall of the main body of the sleeve;

[0096] The sealing mold and the annular rubber cone 250 are placed into the support tube 210. The sealing mold is used to shape the size of the air insulation section inside the tube body and to ensure the proper connection between the outer surface of the annular rubber cone 250 and the inner wall of the tube body.

[0097] The annular rubber cone 250 and the sleeve body are vulcanized to obtain the insulating sleeve 200.

[0098] In this embodiment, the annular rubber cone 250 and the sleeve body are pre-formed separately, and then the annular rubber cone 250 is glued to the sleeve body. This method allows the annular rubber cone 250 and the sleeve body to be formed separately, without having to form the annular rubber cone 250 on the sleeve body after it has been formed.

[0099] It should be noted that after the annular rubber cone 250 is injection molded, it also needs to undergo vulcanization treatment to improve the overall structural strength and integrity of the formed insulating sleeve 200. In some embodiments, the silicone epoxy resin adhesive is divided into component A and component B, wherein the platinum content in component B is 30 ppm, and the Brinell viscosity of component A is 2500 mPa·s.

[0100] In this embodiment, the silicone epoxy resin adhesive is configured in such a way that its bonding ability meets the bonding requirements, while also possessing good insulation properties.

[0101] In some implementations, parameters such as the size and position of the large and small umbrella skirts, the minimum distance between umbrellas, the creepage distance between the large umbrella skirts, and the total arc distance are all within the design range and meet the design requirements.

[0102] In some implementations, the creepage distance of the power cable termination is greater than or equal to 38 kV / mm.

[0103] The creepage distance of the aforementioned power cable terminals is greater than or equal to 38KV / mm, which is better than the creepage distance requirement for power cable terminals and basically meets the needs of all common terminal products on the market.

[0104] In some embodiments, the annular rubber cone 250 is pre-bonded to the inner wall of the support tube 210 by an AB component adhesive.

[0105] In the above-mentioned AB component adhesive, the platinum content in component B is 30 ppm, and the Brinell viscosity of component A is 2500 mPa·s.

[0106] In some implementations, reference Figure 1 The aforementioned power cable terminals also include:

[0107] A rain cover 700 is mounted on a conical shield 500 and surrounds the conical shield 500.

[0108] In this embodiment, the rain cover 700 provides effective rain protection and reduces the impact of rainwater on the terminal.

[0109] In some implementations, reference Figure 1 , Figure 4 Auxiliary fasteners 600 include:

[0110] The tight ring 610 is set on the conical shield 500 and sleeved on the connecting hardware 1100, and is used to connect the connecting hardware 1100 and the conical shield 500.

[0111] The gland 620 is fitted onto the connecting fitting 1100 and secured to the retaining ring 610 by nuts arranged radially along the cable 1000.

[0112] In this embodiment, the pressure cap 620 can be used to better press the conical shield 500 onto the upper flange 220, and the tightening ring 610 can be used to better achieve the connection and sealing between multiple components.

[0113] In some implementations, reference Figure 1 The aforementioned power cable terminals also include:

[0114] Support insulator 800 is mounted on base 100 and is used to mount the power cable terminal on the cable support.

[0115] In this embodiment, the use of support insulator 800 can better facilitate the installation and arrangement of terminals for power cables.

[0116] In some implementations, reference Figure 1 The terminal for power cables also includes:

[0117] 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.

[0118] In this embodiment, the bottom of the base 100 is sealed by the tail grounding sealing tube 900, so that an extremely sealed space can be formed inside the insulating sleeve 200, reducing the impact of external substances and environment on the interior.

[0119] like Figure 5 The diagram shows a flowchart of a method for manufacturing a terminal for a power cable, which is also proposed in an embodiment of this application. The method includes steps S100 to S800.

[0120] In step S100, the cable 1000 is passed through the first through hole of the base 100 and the cable 1000 is pre-treated to expose the connecting conductor.

[0121] In step S200, the cable 1000 is passed through the third through hole of the supporting rubber component 300, and the supporting rubber component 300 is fixed to the base 100.

[0122] 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 to make contact with the supporting rubber part 300 with a pressing force.

[0123] Step S400: Connect the connecting hardware 1100 to the connecting conductor of the cable 1000.

[0124] In step S500, the cable 1000 is passed through the second through hole of the insulating sleeve 200, and the insulating sleeve 200 is pushed down until it is in contact with the stress control cone 400 with a clamping force. The insulating sleeve 200 has a pre-fabricated annular rubber cone 250. The annular rubber cone 250 has a second through hole, the diameter of which is smaller at the end away from the base 100 than at the end closer to the base 100. 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 insulation section, and the area below the top is a solid insulation section. The air insulation section is filled with atmospheric pressure air 1200. The electric field strength per unit length of the air insulation section in the height direction is within a preset field strength tolerance range, wherein the value range corresponding to the preset field strength tolerance range is positively correlated with the working voltage level of the power cable terminal.

[0125] Step S600: Fix the bottom end of the insulating sleeve 200 to the base 100;

[0126] In step S700, the connecting hardware 1100 is inserted through the fifth through hole of the conical shield 500, and the conical shield 500 is fixed to the top of the insulating sleeve 200.

[0127] In step S800, the top of the conical shield 500 is sealed using the auxiliary fastener 600.

[0128] In this embodiment, the assembly of the power cable terminal can be completed through assembly. The assembly process eliminates the need for lengthy processes like using adhesives to assemble the internal components; only assembly parts are required. This significantly improves the installation efficiency of the cable 1000 terminal. Furthermore, because of the assembly process, each component can be prefabricated, eliminating the need for time-consuming inter-stage processes and greatly enhancing production efficiency. In addition, the power cable terminal assembled in this embodiment, as described above, also possesses all the aforementioned beneficial effects of the power cable terminal.

[0129] The above-mentioned cable 1000 pretreatment can be understood as stripping the cable 1000 from the connection part of the cable 1000 to expose the insulation layer, semi-conductive layer, connecting conductor and other structures, and presenting them in a stepped arrangement. The specific amount of each part exposed can be determined according to the wiring process of the terminal to be connected, which will not be elaborated here.

[0130] The aforementioned cable 1000 pretreatment also includes heating and straightening the cable 1000, which makes the cable 1000 more conducive to assembly operations.

[0131] After the aforementioned supporting rubber component 300 is fixed to the base 100, the semi-conductive stress control component 410 in the stress control cone 400 subsequently installed on it needs to be flush with the port of the semi-conductive layer of the cable 1000.

[0132] A stepped structure can be provided at the contact point between the stress control cone 400 and the supporting rubber component 300 so that the supporting rubber component 300 can better assist the stress control cone 400 in completing the position limitation.

[0133] During the process of pushing the insulating sleeve 200 down to be in close contact with the stress control cone 400, the supporting rubber component 300 has been installed in advance, which allows the annular rubber cone 250 and the supporting rubber component 300 to jointly restrict the spatial position of the stress control cone 400.

[0134] The bottom end of the insulating sleeve 200 is fixed to the base 100, which can be accomplished by bolt fasteners.

[0135] The conical shield 500 is fixed to the top of the insulating sleeve 200 by bolt fasteners.

[0136] The sealing of the top of the conical shield 500 using the auxiliary fastener 600 can be accomplished by bolt fasteners.

[0137] It should be noted that for parts that require sealing, a sealing groove and a sealing ring can be used to improve the sealing performance.

[0138] In some embodiments, before the cable 1000 is passed through the first through hole of the base 100, the following steps are also included:

[0139] The tail grounding sealing tube 900 is sleeved on the cable 1000;

[0140] After forming a seal on the top of the conical shield 500 using the auxiliary fastener 600, the following is also included:

[0141] The tail grounding sealing tube 900 is fixed on the base 100, and lead welding rod is used to seal the metal sheath of the tail grounding sealing tube 900 and the cable 1000.

[0142] In this embodiment, in order to achieve a seal between the base 100 and the cable 1000, the tail sealing tube is installed before the base 100 is installed. This allows the tail sealing tube to effectively seal the bottom of the base 100 after the main body of the terminal is assembled, thereby improving the sealing effect of the entire terminal.

[0143] In some embodiments, before the cable 1000 is passed through the first through hole of the base 100, the following steps are also included:

[0144] Install the support insulator 800 on the cable bracket;

[0145] Fix the base 100 onto the support insulator 800.

[0146] In this embodiment, the base 100 is fixedly installed using the support insulator 800, thereby providing a stable foundation for the subsequent installation of the terminal body.

[0147] In some implementations, the support insulator 800 and the base 100 are fixed after the tail grounding sealing tube 900 is sleeved on the cable 1000.

[0148] In some embodiments, after forming a seal at the top of the conical shield 500 using the auxiliary fastener 600, the method further includes:

[0149] A rain cover 700 is fitted over the surface of the conical shield 500 to complete the top seal.

[0150] In this embodiment, the rain cover 700 provides effective rain protection, reducing the impact of rainwater on the terminal. Furthermore, the rain cover 700 is the outermost structure and can be installed after the main structure is completed.

[0151] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application.

Claims

1. A terminal for power cables, 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 fitting; An insulating sleeve has its bottom end connected to the base. An annular rubber cone is prefabricated inside the insulating sleeve. The annular rubber cone has a second through hole, and the diameter of the second through hole at the end away from the base is smaller than the diameter at the end closer to the base. A supporting rubber component is disposed on the base and located within the second through hole, and the supporting rubber component has a third through hole for cable to pass through; A stress control cone has a fourth through hole for the cable to pass through; the stress control cone is supported by the supporting rubber component, such that the outer surface of the stress control cone is in contact with the inner surface of the second through hole; inside the insulating sleeve, the annular rubber cone and the stress control cone are in an air insulation section above the top and a solid insulation section below the top, the air insulation section being filled with atmospheric pressure air; the air insulation section withstands an electric field strength per unit length in the height direction within a preset field strength tolerance range, wherein 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 shield has a fifth through hole for the connecting hardware to pass through, and the bottom end of the conical shield is connected to the top of the insulating sleeve and forms a seal on the top of the insulating sleeve. An auxiliary fastener is used to connect the connecting hardware and the conical shield, and to form a seal on the top of the conical shield.

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

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

4. The power cable terminal according to claim 1, characterized in that, The insulating sleeve includes: A support tube, the bottom end of which is disposed on the base; the annular rubber cone is prefabricated inside the support tube; An upper flange is located at the top of the support tube and is used to connect the conical shield. Silicone rubber umbrella skirt, comprising a large umbrella skirt and a small umbrella skirt alternately arranged on the outer surface of the support tube; The lower flange is located at the bottom of the support tube and is used to connect to the base.

5. The power cable terminal according to claim 1, characterized in that, Also includes: A rain cover is disposed on the conical shield and surrounds the conical shield.

6. The terminal for power cables according to claim 1, characterized in that, The auxiliary fasteners include: A tight ring is provided on the conical shield and sleeved on the connecting hardware for connecting the connecting hardware and the conical shield; A pressure cap is fitted onto the connecting hardware and secured to the tightening ring by nuts arranged radially along the cable.

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

8. The terminal for power cables according to claim 1, characterized in that, Also includes: The tail-end grounding sealing tube is sleeved on the cable and located below the base 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: The cable is threaded through the first through hole in the base, and the cable is pre-treated to expose the connecting conductor; The cable is threaded through the third through hole of the supporting rubber component, and the supporting rubber component is fixed to the base; The cable is passed through the fourth through hole of the stress control cone, and the stress control cone is pushed down until it is in contact with the supporting rubber component under pressure. Connect the connecting hardware 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 makes contact with the stress control cone with a clamping force; wherein, an annular rubber cone is prefabricated inside the insulating sleeve; the annular rubber cone has the second through hole, and the diameter of the second through hole at the end away from the base is smaller than the diameter at the end closer to the base; inside 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 atmospheric pressure air; the electric field strength per unit length of the air insulation section in the height direction is within a preset field strength tolerance range, wherein the value range corresponding to the preset field strength tolerance range is positively correlated with the working voltage level of the power cable terminal; Fix the bottom end of the insulating sleeve to the base; The connecting hardware is inserted through the fifth through hole of the conical shield and the conical shield is fixed to the top of the insulating sleeve; The top of the conical shield is sealed using auxiliary fasteners.

10. The method for manufacturing a terminal for a power cable according to claim 9, characterized in that, Before threading the cable through the first through hole in the base, the method further includes: The tail-end grounding sealing tube is sleeved on the cable; After sealing the top of the conical shield using auxiliary fasteners, the method further includes: The tail grounding sealing tube is fixed to the base, and lead welding rod is used to seal the tail grounding sealing tube to the metal sheath of the cable.

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