Stress cone and capacitance cone split type terminal device of oil-filled cable and installation method

Abstract

The invention relates to the technical field of cable terminals, and provides a stress cone and capacitance cone split type terminal device of an oil-filled cable and an installation method, and the terminal device comprises a stress cone and a capacitance cone which are split. The stress cone is formed by wrapping a plurality of paper tubes with different preset heights on site, the preset height of the paper tube on the innermost layer is the longest, and the preset height of the paper tube on the outermost layer is the shortest; the upper conical surface of the stress cone is an inclined surface and is tightly combined with the capacitance cone; the lower conical surface of the stress cone is a set stress curved surface, and the surface of the set stress curved surface is covered with a metal ground screen and is connected with a capacitance cone end screen and a cable lead layer. The capacitor cone is formed by rolling a whole piece of insulation paper, and a preset number of aluminum foils or capacitive screens are arranged every preset layers of insulation paper during rolling; and insulating oil is filled outside the stress cone and the capacitance cone to form an insulating filling area. The maintenance cost of the cable terminal is reduced, and the maintenance efficiency of the cable terminal is improved.

Description

Technical Field

[0001] This invention relates to the field of cable termination technology, and in particular to a stress cone and capacitance cone separate termination device and installation method for oil-filled cables. Background Technology

[0002] As a core component of cross-sea power transmission, oil-filled submarine cables require essential terminal accessories. These accessories not only ensure the effective transmission of power and signals but also provide necessary protection and support, guaranteeing the safe and reliable operation of the system. However, terminal accessories for high-voltage oil-paper insulated oil-filled cables are difficult to obtain. Damage to these accessories leads to high repair costs and slow response times, and untimely cable fault repairs pose safety hazards to the power grid. Summary of the Invention

[0003] In view of this, the purpose of the present invention is to provide a separate stress cone and capacitance cone terminal device and installation method for oil-filled cables, so as to reduce the maintenance cost of cable terminals and improve the maintenance efficiency of cable terminals.

[0004] In a first aspect, the present invention provides a separate terminal device for a stress cone and a capacitor cone of an oil-filled cable. The terminal includes a separate stress cone and a capacitor cone. The stress cone is formed by wrapping multiple paper tubes of different preset heights on site, with the innermost paper tube having the longest preset height and the outermost paper tube having the shortest preset height. The upper cone surface of the stress cone is an inclined surface, which is tightly connected to the capacitor cone. The lower cone surface of the stress cone is a set stress curved surface, which is covered with a metal grounding shield and connects the end shield of the capacitor cone to the lead layer of the cable. The capacitor cone is made by rolling a whole sheet of insulating paper, and a preset number of aluminum foils or capacitor shields are arranged at every preset number of layers of insulating paper during rolling. The innermost shielding tube of the capacitor shield serves as the zero shield, and the outermost capacitor shield serves as the end shield. The outside of the stress cone and the outside of the capacitor cone are filled with insulating oil to form an insulating filling area, and the insulating medium of the insulating oil is the same as the insulating medium of the oil-filled cable.

[0005] In one optional embodiment, the terminal further includes an insulating outer sheath, current-carrying fittings, a cable shielding tube, a terminal head sealing structure, a lead seal structure, a terminal flange, and a bracket; wherein, the current-carrying fittings include external terminals; the insulating outer sheath is disposed outside the insulating filling area; the insulating outer sheath includes a porcelain sleeve or a hollow composite insulator.

[0006] In an optional approach, the stress surface is calculated according to the following procedure: ; Where L is the axial length of the curve profile; U is the terminal voltage at both ends of the stress cone; R K R is the radius of the maximum diameter of the curve profile; I E is the minimum diameter of the curve.L denoted as , where is the electric field intensity along the axial direction of the curve profile; r is the radius of the cable conductor shielding layer.

[0007] In one alternative approach, the capacitive touchscreen is a semi-conductive capacitive touchscreen; the length of the capacitive touchscreen is calculated as follows: ; Where n is the consecutive number of each capacitor; L0 is the length of the zero screen; L1 is the length of the capacitor screen with a specified number of layers; f is the axial displacement of the conductive insert; b is the radius of the zero screen; t is the insulation thickness of each capacitor screen; ts is the thickness of the capacitor screen; ε2 is the relative permittivity of the cable insulation; ε1 is the relative permittivity of the capacitor cone insulation; and r is the radius of the cable conductor shielding layer.

[0008] In one alternative, the current-carrying fittings are connected to the cable conductor by welding or crimping; the current-carrying fittings, other than the external terminals, are connected to the external terminals by spring contacts or watch strap contacts.

[0009] In one alternative embodiment, the cable shield is made of metal, with its lower end connected to the capacitor screen and its upper end connected to the cable conductor.

[0010] In one alternative embodiment, the terminal head sealing structure includes a shaft sealing structure and a planar sealing structure; the terminal head sealing structure is applied to the external terminal and the cable conductor; the terminal head sealing structure is used between the external terminal and the sealing cover, and a removable sealing plug is installed on the top of the external connector.

[0011] In one alternative configuration, the lead seal structure consists of, from the inside out, a cable lead layer, a reinforcing layer, lead solder, epoxy filler, and a metal halogen shell; an oil filling port is provided at the top of the lead seal structure; the terminal flange is fitted onto the cable, with an insulating outer sheath installed on the upper part of the terminal flange, and the lower part of the terminal flange is sealed to the cable lead sheath using the lead seal structure; insulators are used for insulating support between the terminal flange and the bracket, and the terminal flange is fixed to the bracket.

[0012] Secondly, the present invention provides a method for installing a separate stress cone and capacitor cone terminal of an oil-filled cable. The method includes: obtaining the final position of the cable and cutting the cable at the final position; connecting the cable lead sheath and transverse reinforcement to the base assembly and reinforcing them; winding insulating paper onto the cable core and wrapping it around the stress cone; wherein the stress cone is formed by wrapping multiple paper tubes of different preset heights on site, with the innermost paper tube having the longest preset height and the outermost paper tube having the shortest preset height; the upper cone surface of the stress cone is an inclined surface, which is tightly combined with the capacitor cone; the lower cone surface of the stress cone is a set stress curved surface, the surface of which is covered with a metal grounding shield and connects the capacitor cone end shield to the cable lead layer; after installing the capacitor cone on the stress cone, installing a grounding shield and a cable shielding tube; wherein the capacitor cone is made by rolling a whole sheet of insulating paper, with a preset number of aluminum foils or capacitor shields arranged every preset number of insulating paper layers during rolling; the innermost shielding tube of the capacitor shield serves as the zero shield, and the outermost capacitor shield serves as the end shield.

[0013] In an optional embodiment, the method further includes: after installing and fixing an insulating outer sheath outside the cable shielding tube, sequentially connecting the cable conductor and current-carrying fittings, installing a top cover plate and a lead seal, and connecting the oil pipe to the oil filling port; wherein the current-carrying fittings include external terminals; obtaining detection parameters and determining whether the cable has leakage based on the detection parameters; evacuating the cable terminal and filling it with degassed oil; installing corona shielding and cleaning the cable terminal.

[0014] This invention brings the following beneficial effects: The aforementioned stress cone and capacitor cone split-type terminal device and installation method for oil-filled cables provides a stress cone and capacitor cone split-type terminal. The stress cone is formed by wrapping multiple paper tubes of different preset heights on-site. The height of the paper tube decreases sequentially from the innermost to the outermost. The upper cone surface, which can be cut into an inclined plane on-site, fits tightly with the capacitor cone. The lower cone surface, which can be cut into a set stress surface on-site, is used to uniformly cut the electric field at the cut-off point. The surface of the set stress surface is covered with a metal grounding screen and connects the end screen of the capacitor cone to the lead layer of the cable to form a reliable grounding. The capacitor cone is made by rolling a whole sheet of insulating paper. During rolling, a preset number of aluminum foils or capacitor screens are arranged every preset number of insulating paper layers.

[0015] In this method, the stress cone and capacitance cone are separate components, both made of insulating paper. These are readily available terminal accessories and can be made on-site for oil-filled cable terminal repair. This reduces the barrier to obtaining terminal accessories, lowers cable terminal repair costs, and improves cable terminal repair efficiency.

[0016] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention are realized and obtained in accordance with the structures particularly pointed out in the description, claims and drawings.

[0017] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, preferred embodiments are described below in detail with reference to the accompanying drawings. Attached Figure Description

[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0019] Figure 1 This is a schematic diagram of the structure of a stress cone and capacitor cone split-type terminal device for an oil-filled cable provided in an embodiment of the present invention; Figure 2 A schematic diagram of the stress cone provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the capacitor cone structure provided in an embodiment of the present invention; Figure 4 A schematic diagram of the terminal head sealing structure provided in an embodiment of the present invention; Figure 5 A schematic diagram of the lead seal structure provided in an embodiment of the present invention; Figure 6 A schematic diagram of a separate stress cone and capacitance cone terminal for an oil-filled cable provided in an embodiment of the present invention; Figure 7 This is a flowchart illustrating a method for installing a separate stress cone and capacitance cone terminal of an oil-filled cable, as provided in an embodiment of the present invention. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] As a core component of cross-sea power transmission, oil-filled submarine cables require essential terminal accessories. These accessories not only ensure the effective transmission of power and signals but also provide necessary protection and support, guaranteeing the safe and reliable operation of the system. However, terminal accessories for high-voltage oil-paper insulated oil-filled cables are difficult to obtain. Damage to these accessories leads to high repair costs and slow response times, and untimely cable fault repairs pose safety hazards to the power grid.

[0022] Based on this, the present invention provides a separate terminal device and installation method for oil-filled cables with stress cone and capacitance cone, which can be applied to oil-filled cable terminals, such as in the maintenance of oil-filled cable terminals.

[0023] The present invention discloses a separate termination device for the stress cone and capacitance cone of an oil-filled cable, such as... Figure 1 As shown, the terminal includes a split stress cone 01 and a capacitor cone 02.

[0024] Among them, the stress cone 01 is formed by wrapping multiple paper tubes of different preset heights on site. The innermost paper tube has the longest preset height, and the outermost paper tube has the shortest preset height. The upper cone surface of the stress cone 01 is an inclined surface, which is tightly connected to the capacitor cone 02. The lower cone surface of the stress cone 01 is a set stress surface, which is covered with a metal ground screen and connected to the end screen of the capacitor cone 02 and the cable lead layer.

[0025] For example, stress cone 01 is formed by wrapping 5 to 10 paper tubes of different preset heights on-site, with the innermost paper tube having the longest preset height and the outermost paper tube having the shortest preset height. The upper cone surface of stress cone 01 can be cut into an inclined plane on-site and tightly connected with the capacitor cone above the upper cone surface; the lower cone surface of stress cone 01 is a set stress surface, used to uniformly cut the electric field at the cut-off point. The surface of the set stress surface is covered with a metal grounding screen and connected to the end screen of capacitor cone 02 and the lead layer of the cable to form a reliable ground.

[0026] The capacitor cone 02 is made by rolling a whole sheet of insulating paper. During the rolling process, a preset number of aluminum foils or capacitor screens are arranged every preset number of layers of insulating paper. The innermost shielding tube of the capacitor screen is the zero screen, and the outermost capacitor screen is the last screen.

[0027] For example, a capacitor cone 02 is made by rolling up a whole sheet of insulating paper. Here, an aluminum foil or semi-conductive capacitor screen is arranged every 10 to 15 layers of insulating paper, with the innermost shielding tube of the capacitor screen as the zero screen and the outermost capacitor screen as the end screen.

[0028] Both the stress cone 01 and the capacitor cone 02 are filled with insulating oil to form an insulating filling area 03. The insulating medium of the insulating oil is the same as that of the oil-filled cable.

[0029] The aforementioned oil-filled cable features a separate stress cone and capacitor cone terminal device. The terminal comprises a separate stress cone and capacitor cone. The stress cone is formed by wrapping multiple paper tubes of different preset heights on-site, with the innermost paper tube having the longest preset height and the outermost paper tube having the shortest preset height. The upper cone surface of the stress cone is an inclined plane, which is tightly integrated with the capacitor cone. The lower cone surface of the stress cone is a preset stress curve, which is covered with a metal grounding shield and connects the final shield of the capacitor cone to the lead layer of the cable. The capacitor cone is made by rolling a single sheet of insulating paper, with a preset number of aluminum foils or capacitor shields arranged at every preset number of insulating paper layers during rolling. The innermost shielding tube of the capacitor shield serves as the zero shield, and the outermost capacitor shield serves as the final shield. Both the exterior of the stress cone and the exterior of the capacitor cone are filled with insulating oil, forming an insulating filling area. The insulating medium of the insulating oil is consistent with the insulating medium of the oil-filled cable.

[0030] In this method, the stress cone and capacitance cone are separate components, both made of insulating paper. These are readily available terminal accessories and can be made on-site for oil-filled cable terminal repair. This reduces the barrier to obtaining terminal accessories, lowers cable terminal repair costs, and improves cable terminal repair efficiency.

[0031] In one implementation, the terminal further includes an insulating outer sheath, current-carrying fittings, a cable shielding tube, a terminal head sealing structure, a lead seal structure, a terminal flange, and a bracket; wherein the current-carrying fittings include external terminals. The insulating outer sheath is disposed outside the insulating filling area 03; the insulating outer sheath includes a porcelain sleeve or a hollow composite insulator.

[0032] In practice, current-carrying fittings are located at the cable terminal head, including external terminals, crimp connectors, and current-carrying contacts; the cable shielding tube ensures the cable is rigidly arranged inside the terminal; the terminal head sealing structure ensures reliable sealing of the terminal head; the lead seal structure is located at the bottom of the cable terminal and can be used to connect the terminal flange and the cable lead sheath; the terminal flange is fitted onto the cable, and the bracket supports the overall structure of the terminal.

[0033] In this embodiment, the cable terminal integrates insulation, current carrying, mechanics, and sealing to ensure uniform electric field distribution, reliable electrical connection, reasonable structural stress, and smooth oil circulation.

[0034] In one implementation, such as Figure 2 The diagram shows the structure of stress cone 01. This diagram uses the flat surface of the base plate as a reference plane. The maximum diameter of stress cone 01 is 196 mm. Stress cone 01 is attached to the cable insulation layer, which is typically the outer insulating paper of the cable conductor. Here, the outer insulating paper of the cable conductor is different from the insulating paper surrounding the stress cone. The maximum diameter of the cable insulation layer is 88 mm. The set stress surface of the lower cone surface of stress cone 01 is calculated according to the following process: ; Where L is the axial length of the curve profile; U is the terminal voltage at both ends of stress cone 01; R K R is the radius of the maximum diameter of the curve profile; I E is the minimum diameter of the curve; L denoted as , where is the electric field intensity along the axial direction of the curve profile; r is the radius of the cable conductor shielding layer.

[0035] In one implementation, such as Figure 3 The schematic diagram of capacitor cone 02 shown indicates that the capacitor screen is a semi-conductive capacitor screen; as shown Figure 3 The 37 semi-conductive paper capacitive touchscreens are used. The length of the touchscreens is calculated as follows: ; Where n is the consecutive number of each capacitor; L0 is the length of the zero screen; L1 is the length of the capacitor screen with a specified number of layers; f is the axial displacement of the conductive insert; b is the radius of the zero screen; t is the insulation thickness of each capacitor screen; ts is the thickness of the capacitor screen; ε2 is the relative permittivity of the cable insulation; ε1 is the relative permittivity of the capacitor cone O2 insulation; and r is the radius of the cable conductor shielding layer. Multiple capacitor screens can be connected in series.

[0036] In one implementation, the current-carrying fittings are connected to the cable conductor by welding or crimping; the current-carrying fittings other than the external terminals are connected to the external terminals by spring contacts or watch strap contacts.

[0037] For example, the connection between cable conductors and current-carrying fittings includes the connection between cable conductors, crimp connectors, current-carrying contacts, and external connectors; the connection between cable conductors and current-carrying fittings is achieved by welding or crimping; and the connection between current-carrying fittings (excluding external terminals) and external terminals is achieved using spring contacts or watchband contacts.

[0038] In one implementation, the cable shielding tube is a metal shielding tube, with its lower end connected to the zero screen of the capacitor bank and its upper end connected to the cable conductor.

[0039] For example, the cable body (including the cable conductor and the cable insulation layer) has a certain degree of flexibility. In order to ensure that the cable is rigidly arranged in the terminal, the cable inside the terminal is fitted with a cable shield tube made of metal material. The lower end of the cable shield tube is connected to the zero screen of the capacitor screen, and the upper end is connected to the cable conductor.

[0040] In one implementation, such as Figure 4The diagram shows a terminal head sealing structure, which includes a shaft seal and a planar seal. This terminal head sealing structure is applied to external terminals and cable conductors. For example, a terminal head sealing structure is used between the external terminal and the sealing cover, and a removable sealing plug is installed on top of the external connector.

[0041] In one implementation, such as Figure 5 The diagram shows a lead seal structure, which, from the inside out, consists of a cable lead layer, a reinforcing layer, lead solder, epoxy filler, and a metal halogen shell. An oil filling port is located at the top of the lead seal structure. The lead seal structure also includes a liner; insulating oil can be connected to an oil pump system through the oil filling port at the top of the lead seal structure.

[0042] The terminal flange is fitted onto the cable. An insulating outer sheath is installed on the upper part of the terminal flange, and a lead seal is used to seal the lower part of the terminal flange to the cable's lead sheath. Insulators are used for insulation support between the terminal flange and the bracket, and the terminal flange is fixed to the bracket. Here, the terminal flange is fixed to the terminal bracket, and the bracket provides support for the overall structure of the terminal.

[0043] In one embodiment, such as Figure 6 The diagram shows a separate terminal for an oil-filled cable, consisting of a stress cone and a capacitor cone. Figure 6 In a typical oil-filled cable terminal, there are current-carrying fittings, cable conductors, cable insulation layers, cable shielding tubes, insulating oil, capacitor cones, stress cones, insulating outer sheaths, lead seals, and oil filling ports; oil-filled cable terminals also include equalizing rings and armor layer grounding.

[0044] The present invention discloses a method for installing a separate stress cone and capacitance cone terminal of an oil-filled cable, as shown in the embodiments of the present invention. Figure 7 As shown, the method includes the following steps: Step S702: Obtain the final position of the cable and cut the cable at the final position; For example, to straighten the cable, accurately measure the conductor cutting position from the base upwards, and record the measured length and cut position. Cut the cable using a single-piece sawing method.

[0045] Step S704: Connect the cable lead sheath and transverse reinforcement to the base assembly and reinforce them; wind the insulating paper onto the cable core and wrap it around the stress cone; wherein, the stress cone is formed by wrapping multiple paper tubes of different preset heights on site, with the innermost paper tube having the longest preset height and the outermost paper tube having the shortest preset height; the upper cone surface of the stress cone is an inclined surface, and the upper cone surface is tightly combined with the capacitor cone; the lower cone surface of the stress cone is a set stress curved surface, the surface of the set stress curved surface is covered with a metal grounding screen, and connects the end screen of the capacitor cone to the cable lead layer; For example, if the base support is 6 meters high and the terminal height reaches 5.58 meters, first install the base plate shims, then install the base plate tail tube, adjust the base plate to be level, install the insulating sleeve, and then tighten the fixing bolts.

[0046] Next, insulating paper is wrapped layer by layer around the cable's main insulating paper, forming eight insulating paper tubes of different diameters (e.g., 120 mm to 196 mm). Sufficient tension must be maintained during wrapping to allow the stress cone to bear its own weight and that of the capacitor cone above it; the tension of the 2-meter-wide insulating paper must be uniform throughout. Using a cutting tool, the upper cone surface of the stepped stress cone is cut into an inclined plane, and the lower cone surface into a stress curve. The cut upper cone surface must match and fit snugly with the inner cone surface of the capacitor cone, and the lower cone surface must conform to the stress design curve.

[0047] Step S706: After mounting the capacitor cone on the stress cone, install the grounding shield and cable shield tube; wherein, the capacitor cone is made of a whole sheet of insulating paper, and during the rolling, a preset number of aluminum foil or capacitor screens are arranged at every preset number of layers of insulating paper; the innermost shield tube of the capacitor screen is the zero screen, and the outermost capacitor screen is the final screen.

[0048] For example, a conical mold is used to automatically roll the cone, arrange the capacitor screens, and after drying in an oven, demold and immerse in oil. For assembly, assembly continues until the lower cone opening of the capacitor cone is completely joined to the upper part of the stress cone, a process that involves rinsing with cable oil. The capacitor cone is 2.21 meters high, made of 417 layers of a single sheet of insulating paper, with one semi-conductive paper capacitor screen arranged every 11 layers of insulating paper, for a total of 38 screens. Inside the capacitor screen, a stainless steel shielding tube serves as the zero screen, the outermost layer is wrapped with semi-conductive paper, and a copper sheet is used as the final screen.

[0049] Next, semi-conductive corrugated paper is evenly wrapped around the lower part of the stress cone, and tinned copper wire is used for winding, from the cable lead sheath to the capacitor cone shielding layer, and vertically welded for reliable fixation. The copper wire must be hand-wound densely and evenly, and the flatness of the copper wire welds must maintain the stability of the inner cone surface shape.

[0050] Furthermore, the connector links the cable shielding tube to the capacitor cone zero screen; during field implementation, the shielding tube (e.g., 2683 mm) is slipped over the top of the cable, and the lower end is connected to the capacitor cone zero screen via the connector, secured with screws. The top of the shielding tube is equipotentially connected to the conductor.

[0051] The above-mentioned method for installing the stress cone and capacitor cone of the oil-filled cable in a separate terminal configuration involves: obtaining the final position of the cable and cutting it at that position; connecting the cable lead sheath and transverse reinforcement to the base assembly for reinforcement; winding insulating paper onto the cable core and then wrapping it around the stress cone; wherein the stress cone is formed by wrapping multiple paper tubes of different preset heights on-site, with the innermost paper tube having the longest preset height and the outermost paper tube having the shortest preset height; the upper cone surface of the stress cone is an inclined surface, which is tightly integrated with the capacitor cone; the lower cone surface of the stress cone is a set stress curve surface, which is covered with a metal grounding shield and connects the capacitor cone's end shield to the cable lead layer; after installing the capacitor cone on the stress cone, installing the grounding shield and cable shielding tube; wherein the capacitor cone is made by rolling a whole sheet of insulating paper, with a preset number of aluminum foils or capacitor shields arranged at every preset number of insulating paper layers during rolling; the innermost shielding tube of the capacitor shield serves as the zero shield, and the outermost capacitor shield serves as the end shield.

[0052] In this method, the stress cone and capacitance cone are separate components, both made of insulating paper. These are readily available terminal accessories and can be made on-site for oil-filled cable terminal repair. This reduces the barrier to obtaining terminal accessories, lowers cable terminal repair costs, and improves cable terminal repair efficiency.

[0053] In one implementation, after installing and fixing an insulating outer sheath outside the cable shielding tube, the cable conductor and current-carrying fittings are connected in sequence, a top cover plate and a lead seal are installed, and an oil pipe is connected to the oil filling port; wherein, the current-carrying fittings include external terminals; detection parameters are obtained, and the presence of cable leakage is determined based on the detection parameters; the cable terminal is evacuated and filled with degassed oil; corona shielding is installed, and the cable terminal is cleaned.

[0054] For example, after installing and securing the insulating outer sheath, connect the cable conductor and current-carrying hardware, specifically, install the top flange hardware, seals, and screws. During the insertion of the conductive rod into the spring contact finger, proper alignment is required to ensure reliable insertion.

[0055] Next, install the top cover plate, specifically by bolting the top plate to the terminal flange. Seal the surface and connect the oil pipe. Specifically, treat the lead seal welding surface by applying lead enamel with oil, requiring local freezing of the submarine cable to reduce the impact of the insulating oil on the on-site lead enamel quality. After lead enamel, wrap reinforcing copper wire around the seal, install a Halfer clamp, and pour epoxy to protect the lead seal area and prevent mechanical damage. Finally, connect the oil pipe to the oil filling port.

[0056] Further, check for leaks in the seal; specifically, obtain the test parameters and analyze whether there are leaks in the cable based on the test parameters. Vacuum the cable terminal and fill it with degassed oil. Specifically, this can be done according to IEC 60141-1 standard. Here, the maximum degassed level, i.e., the vacuum pressure during degassed, is a maximum permissible value of 15 mbar; the maximum humidity level, i.e., the maximum permissible water content in the oil is 30 ppm; and the maximum loss angle, i.e., the maximum permissible dielectric loss tangent of the insulating oil (in %), is 0.01.

[0057] After completing the above steps, corona shielding can be installed and the cable terminals cleaned.

[0058] The stress cone and capacitance cone split-type terminal device and installation method for oil-filled cables provided in this embodiment of the invention include a computer-readable storage medium storing program code. The instructions included in the program code can be used to execute the methods described in the preceding method embodiments. For specific implementation, please refer to the method embodiments, which will not be repeated here.

[0059] Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working process of the system and apparatus described above can be referred to the corresponding process in the foregoing method embodiments, and will not be repeated here.

[0060] Furthermore, in the description of the embodiments of the present invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention based on the specific circumstances.

[0061] If the aforementioned functions are implemented as software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, or a portion of the technical solution, can be embodied in the form of a software product. This computer software product is stored in a storage medium and includes several instructions to cause a computer device (which may be a personal computer, server, or network device, etc.) to execute all or part of the steps of the methods described in the various embodiments of the present invention. The aforementioned storage medium includes various media capable of storing program code, such as USB flash drives, portable hard drives, read-only memory (ROM), random access memory (RAM), magnetic disks, or optical disks.

[0062] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for 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. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0063] Finally, it should be noted that the above embodiments are merely specific implementations of the present invention, used to illustrate the technical solutions of the present invention, and not to limit it. The scope of protection of the present invention is not limited thereto. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that any person skilled in the art can still modify or easily conceive of changes to the technical solutions described in the foregoing embodiments within the technical scope disclosed in the present invention, or make equivalent substitutions for some of the technical features; and these modifications, changes, or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention, and should all be covered within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A separate termination device for the stress cone and capacitance cone of an oil-filled cable, characterized in that, The terminal includes a split-type stress cone and a capacitor cone; The stress cone is formed by wrapping multiple paper tubes of different preset heights on site, with the innermost paper tube having the longest preset height and the outermost paper tube having the shortest preset height. The upper cone surface of the stress cone is an inclined surface, and the upper cone surface is tightly connected to the capacitor cone; the lower cone surface of the stress cone is a set stress surface, and the surface of the set stress surface is covered with a metal ground screen and connects the end screen of the capacitor cone to the lead layer of the cable. The capacitor cone is made by rolling a whole sheet of insulating paper. During the rolling process, a preset number of aluminum foils or capacitor screens are arranged every preset number of layers of insulating paper. The innermost shielding tube of the capacitor screen is the zero screen, and the outermost capacitor screen is the last screen. Both the stress cone and the capacitor cone are filled with insulating oil to form an insulating filling area. The insulating medium of the insulating oil is the same as that of the oil-filled cable.

2. The stress cone and capacitance cone separate termination device for oil-filled cables according to claim 1, characterized in that, The terminal also includes an insulating outer sheath, current-carrying fittings, a cable shielding tube, a terminal head sealing structure, a lead seal structure, a terminal flange, and a bracket; wherein, the current-carrying fittings include external wiring terminals; The insulating outer sheath is disposed outside the insulating filling area; the insulating outer sheath includes a porcelain sleeve or a hollow composite insulator.

3. The stress cone and capacitance cone separate termination device for oil-filled cables according to claim 1, characterized in that, The set stress surface is calculated according to the following process: ； Where L is the axial length of the curve profile; U is the terminal voltage at both ends of the stress cone; R K R is the radius of the maximum diameter of the curve profile; I E is the minimum diameter of the curve; L denoted as , where is the electric field intensity along the axial direction of the curve profile; r is the radius of the cable conductor shielding layer.

4. The stress cone and capacitance cone separate termination device for oil-filled cables according to claim 1, characterized in that, The capacitive touchscreen is a semi-conductive capacitive touchscreen; the length of the capacitive touchscreen is calculated according to the following process: ； Where n is the consecutive number of each capacitor; L0 is the length of the zero screen; L1 is the length of the capacitor screen with a specified number of layers; f is the axial displacement of the conductive insert; b is the radius of the zero screen; t is the insulation thickness of each capacitor screen; ts is the thickness of the capacitor screen; ε2 is the relative permittivity of the cable insulation; ε1 is the relative permittivity of the capacitor cone insulation; and r is the radius of the cable conductor shielding layer.

5. The stress cone and capacitance cone separate termination device for oil-filled cables according to claim 2, characterized in that, The current-carrying hardware is connected to the cable conductor by welding or crimping; the current-carrying hardware other than the external terminal is connected to the external terminal by spring contact fingers or watch strap contact fingers.

6. The stress cone and capacitance cone separate termination device for oil-filled cables according to claim 2, characterized in that, The cable shielding tube is made of metal. The lower end of the cable shielding tube is connected to the zero screen of the capacitor screen, and the upper end of the cable shielding tube is connected to the cable conductor.

7. The stress cone and capacitance cone separate termination device for oil-filled cables according to claim 2, characterized in that, The terminal head sealing structure includes a shaft sealing structure and a planar sealing structure; the terminal head sealing structure is applied to the external wiring terminal and the cable conductor; the terminal head sealing structure is used between the external wiring terminal and the sealing cover plate, and a removable sealing oil plug is installed on the top of the external connector.

8. The stress cone and capacitance cone separate termination device for oil-filled cables according to claim 2, characterized in that, The lead seal structure consists of, from the inside out, a cable lead layer, a reinforcing layer, lead solder, epoxy filler, and a metal halogen shell; an oil filling port is provided at the top of the lead seal structure; The terminal flange is fitted onto the cable, with an insulating outer sheath installed on the upper part of the terminal flange, and the lower part of the terminal flange is sealed to the cable lead sheath using the lead seal structure; the terminal flange is insulated and supported by an insulator between it and the bracket, and the terminal flange is fixed to the bracket.

9. A method for installing a separate stress cone and capacitance cone terminal of an oil-filled cable, characterized in that, The method includes: Obtain the final location of the cable and cut the cable at that location; The cable lead sheath and transverse reinforcement are connected to the base assembly and reinforced; insulating paper is wound onto the cable core and wrapped around the stress cone; wherein, the stress cone is formed by wrapping multiple paper tubes of different preset heights on site, with the innermost paper tube having the longest preset height and the outermost paper tube having the shortest preset height; the upper cone surface of the stress cone is an inclined surface, which is tightly combined with the capacitor cone; the lower cone surface of the stress cone is a set stress curved surface, the surface of which is covered with a metal grounding screen and connects the end screen of the capacitor cone to the cable lead layer; After the capacitor cone is mounted on the stress cone, a grounding shield and a cable shield are installed. The capacitor cone is made of a whole sheet of insulating paper, and a preset number of aluminum foils or capacitor screens are arranged at every preset number of layers of insulating paper during the rolling process. The innermost shield tube of the capacitor screen serves as the zero screen, and the outermost capacitor screen serves as the final screen.

10. The method for installing a separate stress cone and capacitance cone terminal of an oil-filled cable according to claim 9, characterized in that, The method further includes: After installing and fixing the insulating outer sheath outside the cable shielding tube, the cable conductor and current-carrying hardware are connected in sequence, the top cover plate and lead seal are installed, and the oil pipe is connected to the oil filling port; wherein, the current-carrying hardware includes external wiring terminals; Obtain the detection parameters and determine whether the cable has a leak based on the detection parameters; Vacuum the cable terminals and fill them with degassed oil; Install corona shielding and clean the cable terminals.

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