An inflatable high voltage insulated cable termination

Abstract

The application discloses an inflatable high-voltage insulated cable terminal, which comprises an outdoor wire clamp, a conductive support, an epoxy resin sleeve, a stress cone and a cable; one end of the epoxy resin sleeve is fixed to an end cover mounting assembly, and the other end is fixed to a bottom plate; a tail pipe and an air valve are arranged on the bottom plate; one end of the cable is in sealed connection with the tail pipe, and the other end is fixed to the end cover mounting assembly through a quick-change connecting piece; the outer surface of the cable in the epoxy resin sleeve is sequentially provided with the conductive support, the stress cone and a semi-conductive shielding tape from left to right, and the conductive support, the stress cone and the semi-conductive shielding tape are fixed into an integral whole through a cone cover; the conductive support is in electric connection with the quick-change connecting piece; the cone cover is fixed to the bottom plate through a cone cover support; a spring bracket is arranged at a contact connection position of the semi-conductive shielding tape and the cone cover; and the spring bracket is fixed to the bottom plate through a pre-tightening device. The terminal has the advantages of safety, explosion prevention, anti-aging, light weight and low maintenance cost.

Description

Technical Field

[0001] This invention relates to the field of high-voltage cable termination technology, specifically to an inflatable high-voltage insulated cable termination. Background Technology

[0002] High-voltage cable terminals, as critical insulation interfaces for cable lines, have evolved in tandem with the cable's insulation system, high-voltage electric field control technology, and polymer materials. Early high-voltage transmission widely used self-contained oil-filled cables with capacitive cone oil-filled cable terminals, relying on oil impregnation for internal insulation. However, this method suffered from drawbacks such as oil leakage, complex sealing, and high maintenance costs. With the large-scale promotion of cross-linked polyethylene (XLPE) extruded cables, fluid-insulated terminals were gradually replaced by dry-type terminals, leading to the development of manually wrapped terminals and heat-shrinkable terminals. In the late 1980s, factory-molded silicone rubber stress cone terminals were introduced. Through optimized geometric configuration, they uniformly dispersed the electric field at the cable shield break, and relied on rubber interference compression to ensure interface insulation performance. This gradually became the mainstream terminal solution for 110kV and above high-voltage and ultra-high-voltage XLPE cables. Outdoor cable terminals are core equipment in high-voltage transmission cable systems, but traditional terminals suffer from drawbacks such as bulkiness, oil leakage, complex installation, and poor explosion-proof performance. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention provides an inflatable high-voltage insulated cable terminal, which is safe, explosion-proof, and anti-aging.

[0004] To achieve the above objectives, the present invention provides the following technical solution: an inflatable high-voltage insulated cable terminal, comprising an outdoor clamp, a quick-connect fitting, a conductive bracket, an epoxy resin sleeve, a stress cone, a tail tube, and a cable; one end of the epoxy resin sleeve is fixed to an end cap mounting assembly, and the other end is fixed to a base plate; a tail tube is provided on the base plate; one end of the cable is sealed to the tail tube, and the other end is fixed to the end cap mounting assembly via the quick-connect fitting; the outdoor clamp is fixedly connected to the end of the quick-connect fitting protruding from the end cap mounting assembly; the cable... A conductive support, a stress cone, and a semi-conductive shielding strip are arranged sequentially from left to right on the outer surface of the epoxy resin sleeve, and the conductive support, stress cone, and semi-conductive shielding strip are fixed as a whole by a cone cover; the conductive support is electrically connected to a quick-connect fitting; the cone cover is fixed to the base plate by a cone cover support; a spring bracket is provided at the contact point between the semi-conductive shielding strip and the cone cover; the spring bracket is fixed to the base plate by a pre-tightening device; an air valve is provided on the upper part of the base plate, and insulating gas is filled into the insulating gas cavity in the sealed epoxy resin sleeve through the air valve.

[0005] Furthermore, the cable is provided with an insulating connecting sleeve at its end in the conductive support; the insulating connecting sleeve is sealed to the conductive support and the stress cone respectively through a sealing sleeve; the sealing sleeve is fixed to the insulating connecting sleeve by a clamp; the stranded conductor passing through the insulating connecting sleeve is tightly connected to the conductive connector provided in the conductive support.

[0006] Furthermore, the conductive connector includes a connector head and an elastic plug; one end of the connector head is provided with an inner connection hole, and the other end is provided with a sealing head; the stranded conductor is pressed against the inner connection hole; the sealing head is sealed to the inner hole of the left section of the conductive bracket through a sealing ring.

[0007] Furthermore, the cable surface is coated with a semi-conductive paint, which is located at the contact point between the cable and the semi-conductive shielding strip.

[0008] Furthermore, the pre-tightening device includes a guide rod, a spring, a pre-tightening plate, and a double-ended screw; the pre-tightening plate is sleeved on the cable located in the tail tube, and both ends of the pre-tightening plate are connected to the bottom plate through the double-ended screw; one end of the guide rod located inside the double-ended screw is fixed to the spring bracket, and the other end passes through the spring and is connected to the pre-tightening plate; the pre-tightening force of the spring bracket on the contact connection between the stress cone, the semi-conductive shielding strip, and the cone cover can be adjusted by the nuts provided on the double-ended screw and the guide rod.

[0009] Furthermore, the epoxy resin sleeve surface is provided with vulcanized solid silicone rubber; a pressure equalizing ring assembly is provided on the vulcanized solid silicone rubber; the pressure equalizing ring assembly includes a pressure ring, a horizontal connecting plate and an angle steel connecting plate; a set of pressure rings are fixedly connected by upper and lower horizontal connecting plates; an angle steel connecting plate is welded to the inner side of the horizontal connecting plate; the angle steel connecting plate is fixedly connected to the end cap mounting assembly by bolts.

[0010] Furthermore, the end cap mounting assembly includes an end cap, an end plate, a mating plate, a lower connecting plate, and an upper pressure plate; one side of the end cap is fixedly connected to an epoxy resin sleeve, and the other side is fixedly connected to the end plate by bolts; the lower connecting plate is fixedly fixed to the end plate by bolts; the upper pressure plate is fixedly fixed to the lower connecting plate by bolts; one end of the mating plate is fixedly connected to the end cap, and the other end is fixedly connected to an angle steel connecting plate; a protective cover covering the upper pressure plate is provided on the end plate.

[0011] Furthermore, the cone cover is provided with embedded parts; the ear plates of the cone cover support are fixedly connected to the embedded parts by bolts.

[0012] Furthermore, a supporting insulator is provided on the base plate; the supporting insulator is fixed to the mounting plate.

[0013] Furthermore, the cable surface is provided with a metal braided shielding layer.

[0014] Beneficial effects: This invention uses an air valve to fill the epoxy resin sleeve with insulating gas for insulation treatment, resulting in a weight far lower than traditional oil-immersed terminals. This achieves lightweighting, making transportation and installation more convenient. It also significantly reduces the corrosion and aging of parts by insulating oil and avoids the problem of insulating oil leakage. It can be used for 220kV and above ultra-high voltage XLPE cable terminals, replacing oil-filled solutions. The quick-change connectors allow for shorter cable pretreatment lengths, reducing stripping and grinding processes, minimizing human error during installation, and shortening construction time. The pre-tightening device allows for adjustment of the contact interface clamping force between the semi-conductive shielding tape and the stress cone, and between the stress cone and the cone cover. Combined with simulation experiments, optimal insulation strength and partial discharge initiation voltage can be obtained, preventing partial discharge and breakdown faults caused by interface gaps. This optimizes the electric field distribution and structural stress, ensuring long-term reliable operation of the terminal. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the overall structure of the present invention.

[0016] Figure 2 for Figure 1 A magnified structural diagram of point H in the diagram.

[0017] Figure 3 for Figure 1 A magnified structural diagram at point K in the diagram.

[0018] Figure 4 for Figure 1 A magnified structural diagram at point M.

[0019] Figure 5 for Figure 1 A magnified structural diagram at point N in the diagram.

[0020] Figure 6 This is an enlarged structural schematic diagram of the conductive connector.

[0021] Figure 7 This is an enlarged schematic diagram of the connection structure between the quick-change connector and the conductive support.

[0022] In the diagram: 1. Insulating gas chamber; 2. Stress cone; 3. Cone cover; 4. Cone cover support; 5. Spring bracket; 6. Gas valve; 7. Base plate; 8. Support insulator; 9. Mounting plate; 10. Conductive connector; 11. Epoxy resin sleeve; 12. Vulcanized solid silicone rubber; 13. Protective cover; 14. Outdoor wire clamp; 15. Equalizing ring assembly; 16. End cover mounting assembly; 17. Quick-connect connector; 18. Conductive bracket; 19. Embedded part; 20. Semi-conductive shielding tape; 21. Semi-conductive paint; 22. Tail pipe; [Electricity / Electricity] Cable 23; Sealing sleeve 24; Jacket 25; Guide rod 26; Spring 27; Pre-tightening plate 28; Double-ended screw 29; Metal braided shielding layer 30; Connector 101; Elastic plug 102; Inner connecting hole 103; Sealing head 104; Pressure ring 151; Horizontal connecting plate 152; Angle steel connecting plate 153; End cap 161; End plate 162; Butt plate 163; Lower connecting plate 164; Upper pressure plate 165; Insulating connecting sleeve 231; Stranded conductor 232. Detailed Implementation

[0023] The present disclosure will now be described in further detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the disclosure. Furthermore, it should be noted that, for ease of description, only the parts relevant to the present disclosure are shown in the accompanying drawings.

[0024] like Figures 1 to 7 As shown, an inflatable high-voltage insulated cable terminal includes an outdoor clamp 14, a quick-connect fitting 17, a conductive support 18, an epoxy resin sleeve 11, a stress cone 2, a tail tube 22, and a cable 23. One end of the epoxy resin sleeve 11 is fixed to an end cap mounting assembly 16, and the other end is fixed to a base plate 7. The tail tube 22 is provided on the base plate 7. One end of the cable 23 is sealed to the tail tube 22, and the other end is fixed to the end cap mounting assembly 16 via the quick-connect fitting 17. The outdoor clamp 14 is fixedly connected to the end of the quick-connect fitting 17 that protrudes from the end cap mounting assembly 16. The outer surface of the cable 23 within the epoxy resin sleeve 11 is provided with the conductive support 18, the stress cone 2, and the semi-conductive shielding strip 20 from left to right, and the conductive support 18, the stress cone 2, and the semi-conductive shielding strip 20 are fixed as a whole by a cone cover 3. Figure 1 , Figure 3 and Figure 7As shown, the conductive bracket 18 is electrically connected to the quick-connect connector 17; the cone cover 3 is fixed to the base plate 7 by the cone cover support 4; a spring bracket 5 is provided at the contact connection between the semi-conductive shielding strip 20 and the cone cover 3. The semi-conductive shielding strip 20 plays the role of improving the electric field at the cable insulation port, maintaining the potential of this area equal to the ground potential, so that the high voltage electric field can only start from the end face of the semi-conductive shielding strip 20 and gradually diffuse along the insulating cone surface, preventing the shielding cut from being directly exposed and generating tip discharge; the spring bracket 5 is fixed to the base plate 7 by a pre-tightening device; an air valve 6 is provided on the base plate 7, and insulating gas is filled into the insulating gas cavity 1 in the sealed epoxy resin sleeve 11 through the air valve 6. This invention uses an air valve 6 to fill the epoxy resin sleeve 11 with insulating gas for insulation treatment. The weight is significantly lower than traditional oil-immersed terminals, achieving lightweight construction, making transportation and installation more convenient. It also greatly reduces the corrosion and aging of components by insulating oil and avoids leakage, thus achieving a balanced electric field. The quick-connect connector 17 allows for shorter pre-treatment lengths of the cable 23, reducing stripping and grinding processes, minimizing human error during installation, and shortening construction time. The pre-tightening device adjusts the clamping force at the contact interface between the semi-conductive shielding tape and the stress cone, and the stress cone and cone cover. Combined with simulation experiments, optimal insulation strength and partial discharge initiation voltage are obtained, preventing partial discharge and breakdown faults caused by interface gaps. This optimizes the electric field distribution and structural stress, ensuring long-term reliable operation of the terminal. The air valve 6 allows for venting for later maintenance, which is simpler and less costly than using insulating oil. It can be used for 220kV and above ultra-high voltage XLPE cable terminals, replacing oil-filled solutions.

[0025] As a preferred embodiment, such as Figure 3 As shown, the end of the cable 23 located in the conductive support 18 is provided with an insulating connecting sleeve 231; the insulating connecting sleeve 231 is sealed to the conductive support 18 and the stress cone 2 respectively through a sealing sleeve 24; the sealing sleeve 24 is fixed to the insulating connecting sleeve 231 through a clamp 25; the stranded conductor 232 passing through the insulating connecting sleeve 231 is tightly connected to the conductive connector 10 provided in the conductive support 18. The sealing sleeve 24 and the clamp 25 ensure the stability and sealing of the connection, avoiding the problem of poor contact of the stranded conductor 232.

[0026] As a preferred embodiment, such as Figure 1 , Figure 3 and Figure 6As shown, the conductive connector 10 includes a connector 101 and an elastic plug 102; one end of the connector 101 is provided with an inner connection hole 103, and the other end is provided with a sealing head 104; the stranded conductor 232 is pressed against the inner connection hole 103; the sealing head 104 is sealed to the inner hole of the left section of the conductive support 18 through a sealing ring. By ensuring sufficient contact between the stranded conductor 232 and the inner connection hole 103 of the conductive connector 10, and by ensuring sufficient electrical connection with the conductive support 18 through the sealing head 104, the stability of the electrical connection is improved.

[0027] As a preferred embodiment, such as Figure 1 and Figure 4 As shown, the surface of the cable 23 is provided with a semi-conductive paint 21, which is located at the contact point between the cable 23 and the semi-conductive shielding strip 20.

[0028] As a preferred embodiment, such as Figure 1 , Figure 2 , Figure 3 , Figure 4 and Figure 5 As shown, the pre-tightening device includes a guide rod 26, a spring 27, a pre-tightening plate 28, and a double-ended screw 29. The pre-tightening plate 28 is sleeved on the cable 23 located in the tail tube 22, and both ends of the pre-tightening plate 28 are connected to the base plate 7 via the double-ended screw 29. One end of the guide rod 26, located inside the double-ended screw 29, is fixed to the spring bracket 5, and the other end passes through the spring 27 and connects to the pre-tightening plate 28. The pre-tightening force of the spring bracket 5 on the contact connection between the stress cone 2, the semi-conductive shielding strip 20, and the cone cover 3 can be adjusted by the nuts provided on the double-ended screw 29 and the guide rod 26. The pre-tightening device provides a stable interface pressure between the stress cone 2, the cone cover 3, and the semi-conductive shielding strip 20, ensuring stable product operation. Simulation is used to test the interface pressure under different pre-tightening forces, and experimental data is used to adjust the pre-tightening force under different operating conditions, thereby achieving the advantages of versatility, safety, and stability. The entire terminal successfully passed all type tests, and the extended test verification showed that the product has sufficient safety margin, supports further reduction in structural size, and can also be iteratively upgraded to higher voltage levels (±500kV and above).

[0029] As a preferred embodiment, such as Figure 1 and Figure 2As shown, the epoxy resin sleeve 11 is coated with vulcanized solid silicone rubber 12; a pressure equalizing ring assembly 15 is mounted on the vulcanized solid silicone rubber 12; the pressure equalizing ring assembly 15 includes a pressure ring 151, a horizontal connecting plate 152, and an angle steel connecting plate 153; a set of pressure rings 151 are fixedly connected by two upper and lower horizontal connecting plates 152; an angle steel connecting plate 153 is welded to the inner side of the horizontal connecting plate 152; the angle steel connecting plate 153 is fixedly connected to the end cap mounting assembly 16 by bolts. The pressure equalizing ring assembly 15 works in conjunction with the pre-tightening device to ensure the stability of the applied force.

[0030] As a preferred embodiment, such as Figure 1 and Figure 2 As shown, the end cap mounting assembly 16 includes an end cap 161, an end plate 162, a mating plate 163, a lower connecting plate 164, and an upper pressure plate 165. One side of the end cap 161 is fixedly connected to an epoxy resin sleeve 11, and the other side is fixedly connected to the end plate 162 by bolts. The lower connecting plate 164 is fixed to the end plate 162 by bolts. The upper pressure plate 165 is fixed to the lower connecting plate 164 by bolts. One end of the mating plate 163 is fixedly connected to the end cap 161, and the other end is fixedly connected to an angle steel connecting plate 153. A protective cover 13 covering the upper pressure plate 165 is provided on the end plate 162. This ensures convenient installation of the terminal and facilitates future upgrades and maintenance.

[0031] As a preferred embodiment, such as Figure 4 As shown, the cone cover 3 is provided with a pre-embedded part 19; the ear plate of the cone cover support 4 is fixedly connected to the pre-embedded part 19 by bolts, which facilitates installation and connection.

[0032] As a preferred embodiment, such as Figure 1 As shown, a supporting insulator 8 is provided on the base plate 7; the supporting insulator 8 is fixed on the mounting plate 9 and is used for the installation and connection of the terminal.

[0033] As a preferred embodiment, such as Figure 1 As shown, a metal braided shielding layer 30 is provided on the surface of the cable 23, and the semi-conductive paint 21 is applied to the outer surface of the metal braided shielding layer 30. The metal braided shielding layer 30 ensures the signal anti-interference capability in the terminal.

[0034] Those skilled in the art should understand that the above embodiments are merely for illustrating the present disclosure and are not intended to limit the scope of the disclosure. Those skilled in the art can make other changes or modifications based on the above disclosure, and these changes or modifications still fall within the scope of the present disclosure.

Claims

1. A gas-filled high-voltage insulated cable terminal, characterized in that, The system includes an outdoor cable clamp, a quick-connect fitting, a conductive support, an epoxy resin sleeve, a stress cone, a tail tube, and a cable. One end of the epoxy resin sleeve is fixed to an end cap mounting assembly, and the other end is fixed to a base plate. A tail tube is mounted on the base plate. One end of the cable is sealed to the tail tube, and the other end is fixed to the end cap mounting assembly via the quick-connect fitting. The outdoor cable clamp is fixedly connected to the end of the quick-connect fitting that protrudes from the end cap mounting assembly. From left to right, the outer surface of the cable within the epoxy resin sleeve is provided with a conductive support, a stress cone, and a semi-conductive shielding strip, which are then fixed together as a whole by a cone cover. The conductive support is electrically connected to the quick-connect fitting. The cone cover is fixed to the base plate by a cone cover support. A spring bracket is provided at the contact point between the semi-conductive shielding strip and the cone cover. The spring bracket is fixed to the base plate by a pre-tightening device. An air valve is provided on the top of the base plate, through which insulating gas is filled into the insulating gas chamber within the sealed epoxy resin sleeve.

2. The gas-filled high-voltage insulated cable terminal according to claim 1, characterized in that, An insulating connecting sleeve is provided at the end of the cable located in the conductive support; the insulating connecting sleeve is sealed to the conductive support and the stress cone respectively through a sealing sleeve; the sealing sleeve is fixed on the insulating connecting sleeve by a clamp; the stranded conductor passing through the insulating connecting sleeve is tightly connected to the conductive connector provided in the conductive support.

3. The gas-filled high-voltage insulated cable terminal according to claim 2, characterized in that, The conductive connector includes a connector head and an elastic plug; one end of the connector head is provided with an inner connection hole, and the other end is provided with a sealing head; the stranded conductor is pressed against the inner connection hole; the sealing head is sealed to the inner hole of the left section of the conductive bracket through a sealing ring.

4. The gas-filled high-voltage insulated cable terminal according to claim 1, characterized in that, The cable surface is coated with a semi-conductive paint, which is located at the contact point between the cable and the semi-conductive shielding strip.

5. A pneumatic high-voltage insulated cable terminal according to claim 1, characterized in that, The pre-tightening device includes a guide rod, a spring, a pre-tightening plate, and a double-ended screw. The pre-tightening plate is sleeved on the cable located in the tail tube, and both ends of the pre-tightening plate are connected to the bottom plate through the double-ended screw. One end of the guide rod located inside the double-ended screw is fixed to the spring bracket, and the other end passes through the spring and is connected to the pre-tightening plate. The pre-tightening force of the spring bracket on the contact connection between the stress cone, the semi-conductive shielding strip, and the cone cover can be adjusted by the nuts set on the double-ended screw and the guide rod.

6. The gas-filled high-voltage insulated cable terminal according to claim 1, characterized in that, The epoxy resin sleeve surface is provided with vulcanized solid silicone rubber; a pressure equalizing ring assembly is provided on the vulcanized solid silicone rubber; the pressure equalizing ring assembly includes a pressure ring, a horizontal connecting plate and an angle steel connecting plate; a set of pressure rings are fixedly connected by two upper and lower horizontal connecting plates; an angle steel connecting plate is welded to the inner side of the horizontal connecting plate; the angle steel connecting plate is fixedly connected to the end cap mounting assembly by bolts.

7. A gas-filled high-voltage insulated cable terminal according to claim 6, characterized in that, The end cap mounting assembly includes an end cap, an end plate, a mating plate, a lower connecting plate, and an upper pressure plate. One side of the end cap is fixedly connected to an epoxy resin sleeve, and the other side is fixedly connected to the end plate by bolts. The lower connecting plate is fixedly fixed to the end plate by bolts. The upper pressure plate is fixedly fixed to the lower connecting plate by bolts. One end of the mating plate is fixedly connected to the end cap, and the other end is fixedly connected to an angle steel connecting plate. A protective cover covering the upper pressure plate is provided on the end plate.

8. A pneumatic high-voltage insulated cable terminal according to claim 1, characterized in that, The cone cover is provided with embedded parts; the ear plates of the cone cover support are fixedly connected to the embedded parts by bolts.

9. A gas-filled high-voltage insulated cable terminal according to claim 1, characterized in that, The base plate is provided with a supporting insulator; the supporting insulator is fixed to the mounting plate.

10. A pneumatic high-voltage insulated cable terminal according to claim 1, characterized in that, The cable surface is provided with a metal braided shielding layer.

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