A polyolefin sheath crosslinked polyethylene insulated power cable

Abstract

The application relates to the technical field of power cables, and discloses a polyolefin sheath crosslinked polyethylene insulated power cable, which comprises an insulated cable body, the insulated cable body is provided with a metal conductor, a crosslinked polyethylene insulation layer and a polyolefin sheath layer, a plurality of metal conductors provided with the crosslinked polyethylene insulation layer are arranged to protrude from the polyolefin sheath layer, and the polyolefin sheath crosslinked polyethylene insulated power cable further comprises a fastening ring, a polyolefin sleeve and a stretching protection structure; the fastening ring is arranged at the end of the polyolefin sheath layer; the polyolefin sleeve is in one-to-one correspondence with the metal conductor; the polyolefin sleeve is arranged on one side of the fastening ring in a sliding mode; and the metal conductor provided with the crosslinked polyethylene insulation layer penetrates through the polyolefin sleeve. Through the technical scheme, the problem that the metal conductor joint is difficult to be used for a long time in a chemical corrosion environment when the metal conductor wrapped with the crosslinked polyethylene insulation layer needs to be exposed from the polyolefin sheath in the laying of the insulated power cable in an environment with a chemical corrosion hidden danger is solved.

Description

Technical Field

[0001] This invention relates to the field of power cable technology, specifically to a polyolefin-sheathed cross-linked polyethylene insulated power cable. Background Technology

[0002] Insulated power cables are the electrical structures used in existing technologies for transmitting electrical energy. They are mainly used for power transmission between power plants, substations, distribution networks, and end users, enabling the transmission of AC, DC, medium and low voltage, and high voltage large-capacity power, ensuring long-distance and low-loss power transmission. The electrical structure of an insulated power cable includes a metal conductor made from metal wires through a stranding process, followed by an extrusion process to extrude a conductor insulation layer on the outside of the metal conductor. Depending on the actual application requirements, to further improve the mechanical properties of the insulated power cable, a special cross-linking extrusion process can be used to prepare a cross-linked polyethylene insulation layer. A shielding layer can then be added to the outside of the cross-linked polyethylene insulation layer to avoid electromagnetic interference. Then, multiple metal conductors are stranded together to form a cable. A steel strip can be used to form an armor layer on the outside of the cable to provide rigid protection for the multiple metal conductors. Finally, an outer sheath is extruded on the outside of the armor layer, completing the outermost structure of the insulated power cable.

[0003] In existing technologies, the outer sheath materials used for insulated power cables are diverse. Generally, the appropriate outer sheath material is selected based on the cable laying environment and requirements. When it is necessary to make the insulated power cable have better flame retardancy, aging resistance, and chemical corrosion resistance, polyolefin materials are often used to prepare polyolefin sheaths to adapt to the laying environment of the insulated power cable. However, when connecting the insulated power cable to the wiring point of the power equipment, it is necessary to peel off a section of the polyolefin sheath to expose the metal conductor wrapped with cross-linked polyethylene insulation layer and connect it to the wiring point. However, the pure cross-linked polyethylene insulation layer is difficult to use for a long time in a chemically corrosive environment, which can easily damage the insulation performance of the insulated power cable. Summary of the Invention

[0004] This invention proposes a polyolefin-sheathed cross-linked polyethylene insulated power cable, which solves the problem in the prior art that when insulated power cables are laid in environments with potential chemical corrosion, part of the metal conductor wrapped with cross-linked polyethylene insulation layer needs to be exposed from the polyolefin sheath, and the metal conductor joints are difficult to use for a long time in chemically corrosive environments.

[0005] The technical solution of the present invention is as follows: A polyolefin-sheathed cross-linked polyethylene insulated power cable includes an insulated cable body, the insulated cable body having a metal conductor, a cross-linked polyethylene insulation layer, and a polyolefin sheath layer, wherein a plurality of metal conductors having the cross-linked polyethylene insulation layer extend from within the polyolefin sheath layer, and further includes: A fastening ring sleeve, wherein the fastening ring sleeve is fitted onto the end of the polyolefin sheath layer; A polyolefin sleeve, wherein the polyolefin sleeve corresponds one-to-one with the metal conductor, the polyolefin sleeve is slidably disposed on one side of the fastening ring, and the metal conductor provided with the cross-linked polyethylene insulation layer passes through the polyolefin sleeve. A tensile protection structure is provided, wherein the side of the polyolefin sleeve away from the polyolefin sheath layer is connected to the tensile protection structure to protect the area where the metal conductor penetrates the polyolefin sleeve. A spiral metal strip is provided inside the polyolefin sleeve, and the spiral metal strip extends out of the polyolefin sleeve and is inserted into the tensile protection structure.

[0006] In one possible implementation, the fastening ring includes two semi-circular ring frames. The inner arc surface of the semi-circular ring frame is provided with a friction layer, which is attached to the polyolefin sheath layer. The semi-circular ring frame has multiple through holes and an arc-shaped groove.

[0007] In one possible implementation, a rigid ring is provided on one side of the polyolefin sleeve, a sliding member is provided on the rigid ring, one side of the sliding member is provided as an arc-shaped sliding plate segment, the arc-shaped sliding plate segment is slidably disposed in the arc-shaped sliding groove, and an abutment groove is provided on the sliding member.

[0008] In one possible implementation, it further includes an abutting support rod and a polyolefin compression ring sleeve. The abutting support rod abuts against the abutting groove. The abutting support rod is provided with a threaded rod that passes through the through hole and is connected to the semi-circular ring frame. The polyolefin sleeve is provided on the side of the polyolefin sleeve near the polyolefin sheath layer.

[0009] In one possible implementation, the tensile protection structure includes an abutment ring, a mounting ring, and a sliding collar. The abutment ring has multiple inclined slots, and one side of the spiral metal strip extends into the inclined slots. Multiple sliding collars are provided between the abutment ring and the mounting ring, and the inner and outer arc surfaces of two adjacent sliding collars are slidably connected.

[0010] In one possible implementation, the mounting ring is provided with a conical fastening cylinder, the inner arc surface of which is in contact with the cross-linked polyethylene insulation layer, and the conical fastening cylinder is provided with multiple cutting ring grooves.

[0011] In one possible implementation, the polyolefin sleeve has multiple mounting grooves on the circumference of one side near the abutment ring, and the mounting grooves are provided with rigid grooves.

[0012] In one possible implementation, an engagement component is provided between the abutment ring and the rigid groove to maintain connection between the abutment ring and the polyolefin sleeve.

[0013] The working principle and beneficial effects of this invention are as follows: When laying insulated cables with polyolefin sheaths in environments with potential chemical corrosion, to ensure corrosion protection for the exposed cross-linked polyethylene insulation and metal conductors, after peeling off a section of the polyolefin sheath, fastening rings are placed on the outside of the polyolefin sheath and the ends of the polyolefin sheath are tightened. Then, a number of polyolefin sleeves corresponding to the number of metal conductors are placed on the outside of the cross-linked polyethylene insulation. The polyolefin sleeves are used to provide corrosion protection for the cross-linked polyethylene insulation and to avoid damaging the insulation performance of the cross-linked polyethylene insulation.

[0014] During the installation process of this invention, the required lengths of the multiple metal conductors extending from the polyolefin sheath are not consistent. After the metal conductors penetrate the polyolefin sheath, a section is still exposed. A tension protection structure is then used to continue to be fitted on the outside of the metal conductors. A conical fastening cylinder is provided on one side of the tension protection structure. The conical fastening cylinder seals the joint between the metal conductors and the cross-linked polyethylene insulation layer, further ensuring the insulation performance. In addition, a spiral metal belt is used inside the polyolefin sheath to enhance the overall support of the polyolefin sheath, thereby improving the overall strength of the polyolefin sheath. Attached Figure Description

[0015] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0016] Figure 1 This is a schematic diagram of the structure of a polyolefin-sheathed cross-linked polyethylene insulated power cable according to the present invention; Figure 2 For the present invention Figure 1 Schematic diagram of the structure of the medium-insulated cable body; Figure 3 For the present invention Figure 1 A schematic diagram of the structure of the polyolefin sleeve and the semi-circular ring frame; Figure 4 For the present invention Figure 1Schematic diagram of the middle fastening ring sleeve; Figure 5 For the present invention Figure 1 Schematic diagram of the polyolefin sleeve and tensile protection structure; Figure 6 For the present invention Figure 5 A magnified structural diagram of point A in the middle; Figure 7 For the present invention Figure 5 A magnified structural diagram of point B in the middle section; Figure 8 This is a schematic diagram of the structure of the spiral metal strip, rigid ring, and polyolefin compression ring in this invention; Figure 9 This is a schematic diagram of the tensile protection structure and the inclined slot in this invention.

[0017] In the diagram: 1. Insulated cable body; 2. Metal conductor; 3. Cross-linked polyethylene insulation layer; 4. Polyolefin sheath layer; 5. Fastening ring; 6. Polyolefin sleeve; 7. Spiral metal strip; 8. Semi-circular ring frame; 9. Friction layer; 10. Through hole; 11. Arc-shaped groove; 12. Rigid ring; 13. Sliding component; 14. Arc-shaped sliding plate segment; 15. Abutment support rod; 16. Threaded rod; 17. Polyolefin compression ring; 18. Abutment ring; 19. Mounting ring; 20. Inclined slot; 21. Sliding collar; 22. Conical fastening cylinder; 23. Cut ring groove; 24. Mounting groove; 25. Rigid groove; 26. Abutment support plate; 27. Abutment slot; 28. Bending support plate; 29. ​​Abutment tooth block. Detailed Implementation

[0018] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0019] This embodiment presents a polyolefin-sheathed cross-linked polyethylene insulated power cable. Please refer to [link to relevant documentation]. Figure 1 and Figure 2The cable body 1 includes an insulated cable body 1, which has a metal conductor 2, a cross-linked polyethylene insulation layer 3, and a polyolefin sheath layer 4. Multiple metal conductors 2 with cross-linked polyethylene insulation layers 3 extend from the polyolefin sheath layer 4. In the production process, the insulated cable body 1 is first produced by drawing metal wire cores, and then the multiple metal wire cores are twisted to form metal conductors 2. Cross-linked polyethylene insulation layers 3 are extruded on the outside of the metal conductors 2 through a cross-linking extrusion process. Depending on the requirements of the laying environment, when it is necessary to isolate electromagnetic interference, a shielding layer can be set on the outside of the cross-linked polyethylene insulation layer 3. The shielding layer includes a semiconductor shielding layer or a metal shielding layer. Then, the multiple metal conductors 2 are twisted into a cable by a stranding process, and then an armor layer is set on the outside of the stranded multiple metal conductors 2. Finally, a polyolefin sheath layer 4 is set on the outside of the armor layer through an extrusion process, thereby producing the insulated cable body 1.

[0020] In view of the usage environment of the insulated cable body 1 in this invention, when preparing the cross-linked polyethylene insulation layer 3, low-density polyethylene is used as the main material, inert corrosion-resistant inorganic filler is added, and then polyolefin elastomer and coupling agent are added as compatibilizers. Finally, peroxide cross-linking or silane warm water cross-linking is used to make the prepared cross-linked polyethylene insulation layer 3 more corrosion resistant.

[0021] Also includes fastening ring 5, please refer to Figure 3 and Figure 4 The fastening ring 5 is fitted onto the end of the polyolefin sheath layer 4. The fastening ring 5 includes two semi-circular ring frames 8. The inner arc surface of the semi-circular ring frame 8 is provided with a friction layer 9, which is attached to the polyolefin sheath layer 4. The semi-circular ring frame 8 has multiple through holes 10 and arc-shaped grooves 11. After peeling off a part of the polyolefin sheath layer 4, the two semi-circular ring frames 8 are combined and set at the port of the polyolefin sheath layer 4. Connecting pieces are provided on both sides of the two semi-circular ring frames 8. After the two connecting pieces are attached, they are connected with bolts to fix the two semi-circular ring frames 8 together on the outside of the polyolefin sheath layer 4. Then, the friction layer 9 is slightly deformed and rubs against the polyolefin sheath layer 4, thereby fixing the fastening ring 5 composed of the two semi-circular ring frames 8 to the surface of the polyolefin sheath layer 4.

[0022] The polyolefin sheath 6 corresponds one-to-one with the metal conductor 2. Please refer to [link / reference]. Figure 3The polyolefin sleeve 6 is slidably disposed on one side of the fastening ring 5. The metal conductor 2, which is provided with a cross-linked polyethylene insulation layer 3, passes through the polyolefin sleeve 6. When it is necessary for the metal conductor 2 to pass through the polyolefin sleeve 6, a certain gap needs to be maintained between the metal conductor 2 and the port of the polyolefin sleeve 6. Then, the metal conductor 2 is smoothly passed through the polyolefin sleeve 6. In order to provide sufficient protection for the metal conductor 2 and the cross-linked polyethylene insulation layer 3, the polyolefin sleeve 6 is moved towards the polyolefin sheath layer 4, so that the polyolefin sleeve 6 contacts the filling layer inside the insulated cable body 1, thereby achieving sealing protection for the area between the metal conductor 2 and the filling layer.

[0023] A rigid ring 12 is provided on one side of the polyolefin sleeve 6. Please refer to [link / reference]. Figure 8 A sliding member 13 is provided on the rigid ring sleeve 12. One side of the sliding member 13 is configured as an arc-shaped sliding plate segment 14, which is slidably disposed within an arc-shaped groove 11. An abutment groove is formed on the sliding member 13. After the polyolefin sleeve 6 is sleeved on the outside of the cross-linked polyethylene insulation layer 3, one end of the polyolefin sleeve 6 needs to be fitted with the filling layer inside the insulated cable body 1. The arc-shaped sliding plate segment 14 slides within the arc-shaped groove 11, and the arc-shaped sliding plate segment 14 and the arc-shaped groove 11 provide better sliding stability. It also includes the abutment support 15 and the polyolefin compression ring 17, see [link / reference] Figure 3 The abutting support rod 15 abuts against the abutting groove. The abutting support rod 15 is provided with a threaded rod 16, which passes through the through hole 10 and is connected to the semi-circular ring frame 8. A polyolefin compression ring sleeve 17 is provided on the side of the polyolefin sleeve 6 near the polyolefin sheath layer 4. The abutting support rod 15 abuts against the abutting groove, and then the threaded rod 16 passes through the through hole 10. After the polyolefin compression ring sleeve 17 abuts against the filling layer, nuts are used on both sides of the through hole 10 to thread the threaded rod 16, so that the position of the polyolefin sleeve 6 is kept fixed.

[0024] The side of the polyolefin sleeve 6 away from the polyolefin sheath layer 4 is connected to a tensile protection structure; please refer to [link / reference]. Figure 5 and Figure 9To protect the area where the metal conductor 2 penetrates the polyolefin sleeve 6, the tensile protection structure includes an abutment ring 18, a mounting ring 19, and sliding collars 21. The abutment ring 18 has multiple inclined slots 20, and one side of the spiral metal strip 7 extends into the inclined slot 20. Multiple sliding collars 21 are positioned between the abutment ring 18 and the mounting ring 19. The inner and outer arc surfaces of adjacent sliding collars 21 are slidably connected. This allows for adaptation to different distances between multiple metal conductors 2 and wiring positions. After uniformly placing the polyolefin sleeve 6 outside the metal conductor 2, the abutment ring 18 is positioned to connect with the polyolefin sleeve 6. The process involves first inserting one side of multiple spiral metal strips 7 into the corresponding inclined slots 20, fixing the spiral metal strips 7 with the abutment ring 18 to improve the overall tightness of the polyolefin sleeve 6 and prevent the polyolefin sleeve 6 from collapsing or deforming during use. Then, multiple sliding collars 21 are moved towards the mounting ring 19 during sliding. By adjusting the overlap area between the multiple sliding sleeves, the tensile length between the multiple sliding sleeves is adjusted, thereby sealing the area between the abutment ring 18, the mounting ring 19, and the sliding collars 21 and the port of the polyolefin sleeve 6 from the cross-linked polyethylene insulation layer 3.

[0025] The mounting ring 19 is provided with a conical fastening cylinder 22, please refer to Figure 5 The inner arc surface of the conical fastening cylinder 22 is in contact with the cross-linked polyethylene insulation layer 3. Multiple cutting ring grooves 23 are provided on the conical fastening cylinder 22. The metal conductor 2 wrapped with the cross-linked polyethylene insulation layer 3 extends out from the abutment ring 18, so that the inner arc surface of the conical fastening cylinder 22 seals the joint between the cross-linked polyethylene insulation layer 3 and the metal conductor 2. According to the size of different metal conductors 2, the corresponding cutting ring grooves 23 can be cut with a cutting tool to determine the minimum diameter of the conical fastening cylinder 22, so that the inner wall of the conical fastening cylinder 22 corresponds to the outer wall size of the cross-linked polyethylene insulation layer 3.

[0026] The polyolefin sleeve 6 contains multiple spiral metal strips 7. Please refer to [link / reference]. Figure 3 and Figure 8 The spiral metal strip 7 extends from the polyolefin sleeve 6 and is inserted into the tensile protection structure. The use of the spiral metal strip 7 improves the circumferential load-bearing capacity of the polyolefin sleeve 6 and prevents the polyolefin sleeve 6 from collapsing and deforming during long-term use. In addition, multiple spiral metal strips 7 can also protect the metal conductor 2 and the cross-linked polyethylene insulation layer 3.

[0027] The polyolefin sleeve 6 has multiple mounting grooves 24 on its circumference near the abutment ring 18. Please refer to [link / reference]. Figure 3 and Figures 5 to 7A rigid groove 25 is provided within the mounting groove 24. An engaging component is provided between the abutting ring 18 and the rigid groove 25 to maintain the connection between the abutting ring 18 and the polyolefin sleeve 6. The engaging component includes an abutting support plate 26, which is disposed within the rigid groove 25. Abutting slots 27 are provided on both sides of the abutting support plate 26. Two bent support plates 28 are provided on the abutting ring 18 corresponding to each abutting support plate 26. Multiple abutting teeth 29 are provided at the adjacent ends of the two bent support plates 28. The abutting teeth 29 are inserted into the abutting slots 27 to maintain the connection between the polyolefin sleeve 6 and the abutting ring 18. The sleeve 6 is connected to the abutment ring 18. In actual use, the two bent support plates 28 are first inserted into the corresponding hard grooves 25. The abutment teeth 29 on the two bent support plates 28 contact the abutment support plate 26. Through the special inclined meshing design of the abutment slot 27 and the abutment teeth 29, the bent support plate 28 can be slightly bent when it moves into the hard groove 25. When the movement of the bent support plate 28 stops, the abutment teeth 29 on the bent support plate 28 enter the abutment slot 27, so that the abutment ring 18 and the polyolefin sleeve 6 remain connected.

[0028] During use, the polyolefin sheathed cross-linked polyethylene insulated power cable first peels off the polyolefin sheath layer 4 and filler on one side of the insulated cable body 1, making the multiple metal conductors 2 independent of each other. Then, the polyolefin sleeve 6 is sleeved on the cross-linked polyethylene insulation layer 3 outside the metal conductors 2. Then, by using the cooperation between the abutment support rod 15 and the sliding member 13, the polyolefin sleeve 6 is fixed to the outside of the metal conductors 2, and the polyolefin compression ring 17 abuts against the filler layer.

[0029] Then, based on the outer diameter of the metal conductor 2 and the cross-linked polyethylene insulation layer 3, the corresponding area of ​​the conical fastening cylinder 22 is selected to be retained. Then, the metal conductor 2 is made to pass through the conical fastening cylinder 22, so that the abutment ring 18 is connected to the polyolefin sleeve 6. Then, the multiple sliding collars 21 are stretched so that the conical fastening cylinder 22 seals the joint between the metal conductor 2 and the cross-linked polyethylene insulation layer 3, thereby achieving corrosion protection for the exposed parts of the metal conductor 2 inside and outside the polyolefin sheath layer 4.

[0030] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A polyolefin-sheathed cross-linked polyethylene insulated power cable, comprising an insulated cable body (1), the insulated cable body (1) having a metal conductor (2), a cross-linked polyethylene insulation layer (3), and a polyolefin sheath layer (4), wherein a plurality of metal conductors (2) having the cross-linked polyethylene insulation layer (3) extend from within the polyolefin sheath layer (4), characterized in that, Also includes: Fastening ring (5), the fastening ring (5) is sleeved on the end of the polyolefin sheath layer (4); Polyolefin sleeve (6), the polyolefin sleeve (6) corresponds one-to-one with the metal conductor (2), the polyolefin sleeve (6) is slidably disposed on one side of the fastening ring (5), and the metal conductor (2) provided with the cross-linked polyethylene insulation layer (3) penetrates the polyolefin sleeve (6). A tensile protection structure is provided on the side of the polyolefin sleeve (6) away from the polyolefin sheath layer (4) to protect the area where the metal conductor (2) penetrates the polyolefin sleeve (6). Spiral metal strip (7), a plurality of spiral metal strips (7) are provided inside the polyolefin sleeve (6), the spiral metal strips (7) extend out from the polyolefin sleeve (6) and are inserted into the tensile protection structure; The tensile protection structure includes: Abutting ring (18) and mounting ring (19), wherein the abutting ring (18) is provided with a plurality of inclined slots (20), and one side of the spiral metal strip (7) extends into the inclined slots (20); Sliding collar (21), a plurality of sliding collars (21) are provided between the abutment ring (18) and the mounting ring (19), and the inner arc surface and outer arc surface of two adjacent sliding collars (21) are slidably connected; The mounting ring (19) is provided with a conical fastening cylinder (22), the inner arc surface of the conical fastening cylinder (22) is in contact with the cross-linked polyethylene insulation layer (3), and multiple cutting ring grooves (23) are provided on the conical fastening cylinder (22).

2. The polyolefin-sheathed cross-linked polyethylene insulated power cable according to claim 1, characterized in that, The fastening ring (5) includes: Two semi-circular ring frames (8) are provided. A friction layer (9) is provided on the inner arc surface of the semi-circular ring frame (8). The friction layer (9) is attached to the polyolefin sheath layer (4). Multiple through holes (10) are provided on the semi-circular ring frame (8). An arc-shaped groove (11) is provided on the semi-circular ring frame (8).

3. The polyolefin-sheathed cross-linked polyethylene insulated power cable according to claim 2, characterized in that, A rigid ring (12) is provided on one side of the polyolefin sleeve (6), and a sliding member (13) is provided on the rigid ring (12). One side of the sliding member (13) is provided as an arc-shaped sliding plate segment (14), which is slidably disposed in the arc-shaped sliding groove (11). An abutment groove is provided on the sliding member (13).

4. A polyolefin-sheathed cross-linked polyethylene insulated power cable according to claim 3, characterized in that, Also includes: Abutting support rod (15) abuts against the abutting groove. A threaded rod (16) is provided on the abutting support rod (15). The threaded rod (16) passes through the through hole (10) and is connected to the semi-circular ring frame (8). Polyolefin compression ring (17) is provided on the side of the polyolefin sleeve (6) near the polyolefin sheath layer (4).

5. A polyolefin-sheathed cross-linked polyethylene insulated power cable according to claim 1, characterized in that, The polyolefin sleeve (6) has multiple mounting grooves (24) on the circumference of the side near the abutment ring (18), and a hard groove (25) is provided in the mounting groove (24).

6. A polyolefin-sheathed cross-linked polyethylene insulated power cable according to claim 5, characterized in that, An engagement assembly is provided between the abutment ring (18) and the hard groove (25) to maintain the connection between the abutment ring (18) and the polyolefin sleeve (6).

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