A prefabricated water-blocking copper core high-voltage cable

Abstract

The present invention relates to the field of cable manufacturing technology, and discloses a prefabricated water-blocking copper core high-voltage cable, comprising a copper core cable and a prefabricated water-blocking layer. The copper core cable is composed of a metal conductor, a cross-linked polyethylene insulation layer, a semi-conductive shielding layer, a metal shielding layer, and a polyethylene sheath. The prefabricated water-blocking layer comprises a prefabricated water-blocking bag and a prefabricated leak-proof bag. The outer sides are sequentially provided with a water-absorbing shrinkage belt, a first waterproof sealing layer, a steel belt armor layer, and a second waterproof sealing layer. The prefabricated water-blocking bag dissolves in water, and the water-blocking powder expands to form a physical barrier. The prefabricated leak-proof bag ruptures under pressure to release the leak-proof agent to plug the leak. The water-absorbing shrinkage belt shrinks and squeezes when it comes into contact with water to enhance the water-blocking effect. The cable uses a dual mechanism of physical water blocking and chemical leak-proofing, combined with a prefabricated design and a multi-layer protective structure, to improve water-blocking performance, electrical performance, and mechanical strength, simplify construction and maintenance, and is suitable for high-voltage power transmission scenarios.

Description

Technical Field

[0001] The present invention relates to the technical field of cable manufacturing, in particular to a prefabricated water-blocking copper core high-voltage cable. Background Art

[0002] In high-voltage power transmission scenarios, cables are often exposed to moisture, water, or high humidity, such as in underground burial, submarine installation, and tunneling. Moisture intrusion can cause insulation aging, degrade electrical performance, and even cause short circuits, seriously threatening the safety and stability of power transmission. An efficient water-blocking structure is key to ensuring the long-term, reliable operation of high-voltage cables. It not only prevents energy loss and equipment damage caused by moisture penetration, but also reduces operation and maintenance costs and minimizes power outages, playing a vital role in ensuring the continued stable operation of power systems.

[0003] Existing water-blocking cables often rely solely on a single water-blocking mechanism, such as physical water-blocking materials or chemical leak-proofing agents. These mechanisms have limited water-blocking efficiency and reliability, especially when the outer protective layer is damaged, making it difficult to quickly block the water diffusion path. Some solutions lack a high degree of prefabrication, making them difficult to install on-site as needed and requiring fabrication during cable production, increasing costs. Furthermore, traditional structures lack mechanical strength, making them susceptible to damage from external forces in complex installation environments and losing their water-blocking properties. Maintenance also requires costly replacement of entire components. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that the existing water-blocking cables in the prior art have the disadvantages of being high in cost and difficult to maintain. For this reason, we propose a prefabricated water-blocking copper core high-voltage cable.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions: a prefabricated water-blocking copper core high-voltage cable, comprising: a copper core cable and a prefabricated water-blocking layer, the copper core cable comprises a metal conductor, the metal conductor is twisted with high-purity copper material, which can increase the cross-sectional area of ​​the conductor, reduce the resistance to reduce the loss of power transmission, and enhance the flexibility of the cable for easy laying and installation; the metal conductor is wrapped with a cross-linked polyethylene insulation layer, the cross-linked polyethylene insulation layer has excellent electrical insulation performance, chemical stability and mechanical strength, and can effectively prevent current leakage to ensure the safe transmission of power; the outside of the cross-linked polyethylene insulation layer is wrapped with a semi-conductive shielding layer, the semi-conductive shielding layer is divided into two layers, the inner layer fits the uniform surface electric field of the conductor, and the outer layer is located between the insulation layer and the metal shielding layer to make the outer surface electric field of the insulation layer uniform, thereby improving the working stability and service life of the insulation layer; the semi-conductive shielding layer is wrapped with a metal shielding layer on the outside, and the metal shielding layer is wrapped with copper tape or copper wire to shield electricity The electromagnetic field inside the cable prevents electromagnetic interference to external electronic equipment, and at the same time serves as a short-circuit current path to ensure the safety of personnel and equipment when the cable fails; the metal shielding layer is wrapped with a polyethylene sheath, which provides physical protection for the copper core cable; the prefabricated water-blocking layer includes a prefabricated water-blocking bag and a prefabricated leak-proof bag, which are wrapped around the outside of the copper core cable, and the prefabricated water-blocking bag adopts a polyvinyl alcohol water-soluble packaging bag, which is filled with water-blocking powder, and the prefabricated leak-proof bag adopts a plastic packaging bag with a prefabricated pressure rupture, which is filled with liquid leak-proof agent, and the outside of the prefabricated water-blocking bag and the prefabricated leak-proof bag are wrapped with a water-absorbing shrinkage tape, and the outside of the water-absorbing shrinkage tape is wrapped with a first waterproof sealing layer, and the outside of the first waterproof sealing layer is wrapped with a steel belt armor layer, and the outside of the steel belt armor layer is wrapped with a second waterproof sealing layer, and the first waterproof sealing layer and the second waterproof sealing layer are both wrapped with aluminum-plastic composite tape and low-density polyethylene hot-melt adhesive strip and then hot-melt bonded to form a moisture-proof sealing barrier.

[0006] Preferably, the prefabricated water-blocking bag and the prefabricated leak-sealing bag are alternately arranged on the outside of the copper core cable, and the water-absorbing shrinkage tape is spirally wrapped around the outside of the prefabricated water-blocking bag and the prefabricated leak-sealing bag, and the overlapping part of each circle is greater than half of the width of the water-absorbing shrinkage tape to ensure that the water-blocking structure evenly covers the cable surface and enhances the water-blocking sealing.

[0007] Preferably, the first waterproof sealing layer includes a first aluminum-plastic strip and a first polyethylene hot-melt adhesive strip. The first aluminum-plastic strip adopts an ultra-thin aluminum-plastic composite strip with good flexibility and moisture resistance. The first aluminum-plastic strip is spirally wound on the outside of the water-absorbing shrinkage strip, and the overlapping part of each circle is greater than half of the width of the first aluminum-plastic strip. The first polyethylene hot-melt adhesive strip is reversely wound on the outside of the first aluminum-plastic strip at the same angle, and the overlapping part of each circle is greater than 70% of the width of the first polyethylene hot-melt adhesive strip. After heating, it is tightly bonded to the aluminum-plastic strip and the cable surface to form a first waterproof barrier.

[0008] Preferably, the gaps between the first polyethylene hot melt adhesive strips are sealed by hot melt fusion to eliminate the gaps and ensure that the waterproof sealing layer has no leakage points.

[0009] Preferably, the steel belt armor layer is spirally wound on the outside of the first waterproof sealing layer, and the overlap width of the steel belt armor layer is greater than 20 mm, and is fixed by rivets or clamps to enhance the integrity and resistance to external impact.

[0010] Preferably, the second waterproof sealing layer includes a second aluminum-plastic strip and a second polyethylene hot-melt adhesive strip. The second aluminum-plastic strip is spirally wound on the outside of the steel belt armor layer, and the overlapping portion of each turn is greater than half of the width of the second aluminum-plastic strip. The second polyethylene hot-melt adhesive strip is reversely wound on the outside of the second aluminum-plastic strip at the same angle, and the overlapping portion of each turn is greater than 70% of the width of the second polyethylene hot-melt adhesive strip, forming a double waterproof barrier with the first waterproof sealing layer to enhance the water-blocking reliability in a humid environment.

[0011] Preferably, the gaps between the second polyethylene hot melt adhesive strips are sealed by hot melt fusion, thereby strengthening the integrity of the second waterproof sealing layer and forming a composite system of physical barrier and chemical sealing with the first layer.

[0012] Preferably, the water-blocking powder in the prefabricated water-blocking package is one of acrylic acid grafted modified starch water-blocking powder, ethyl cellulose clad water-blocking powder and sodium carboxymethyl cellulose water-blocking powder; acrylic acid grafted modified starch water-blocking powder is suitable for direct burial of medium and low voltage cables and submarine cable joints; ethyl cellulose clad water-blocking powder is suitable for 110kV and above high-voltage cables and subway tunnels; sodium carboxymethyl cellulose water-blocking powder is suitable for moisture-proofing in underground mines and cables in urban green belts.

[0013] Preferably, the sealant in the sealant bag is one of a two-component polyurethane sealant, a silicone-modified epoxy resin sealant and a one-component moisture-curing silicone rubber sealant; the two-component polyurethane sealant is suitable for submarine cable repair and terminal head sealing; the silicone-modified epoxy resin sealant is suitable for cables in chemical parks and salt spray environments; the one-component moisture-curing silicone rubber sealant is suitable for cables in high-rise building shafts and under airport runways.

[0014] Preferably, the water-absorbing shrinkage tape is one of a polyester fiber composite water-absorbing shrinkage tape, a hydrogel fiber shrinkage tape and a shape memory polymer shrinkage tape; the polyester fiber composite water-absorbing shrinkage tape is suitable for scenarios that withstand mechanical stress; the hydrogel fiber shrinkage tape is suitable for rapid water-blocking environments; the shape memory polymer shrinkage tape can pre-program the shrinkage path to adapt to complex breaches.

[0015] The technical effects and advantages of the present invention are as follows: This solution arranges prefabricated water-blocking bags and prefabricated leak-proof bags alternately on the outside of the copper core cable, and cooperates with water-absorbing shrinkage tape and multi-layer protective structure to form a convenient and efficient water-blocking system. Its beneficial effects are reflected in: the prefabricated water-blocking structure realizes standardized production and rapid installation, greatly simplifying the construction process; when the outer layer of the cable is damaged, the water-absorbing shrinkage tape shrinks rapidly when it encounters water, and produces a synergistic effect with the water-blocking powder when it absorbs water and expands, blocking the moisture diffusion path through physical extrusion, and at the same time squeezing the prefabricated leak-proof bag, so that the internal liquid leak-proof agent is released and quickly cross-linked and condensed, forming a chemical sealing layer at the rupture. This dual mechanism of physical water blocking and chemical leak plugging can quickly build a composite barrier when water invades, effectively ensuring the safe operation of the cable in a humid environment, while the steel belt armor and double-layer waterproof sealing layer further enhance the mechanical strength and water-blocking reliability of the cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The disclosure of the present invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. In the accompanying drawings, the same reference numerals are used to refer to the same components.

[0017] Figure 1 It is a schematic diagram of the appearance structure of the present invention.

[0018] Legend: 1. Copper core cable; 101. Metal conductor; 102. Cross-linked polyethylene insulation layer; 103. Semi-conductive shielding layer; 104. Metal shielding layer; 105. Polyethylene sheath; 2. Prefabricated water-blocking layer; 3. Prefabricated water-blocking bag; 4. Prefabricated leak-proof bag; 5. Water-absorbing shrinkage tape; 6. First waterproof sealing layer; 601. First aluminum-plastic strip; 602. First polyethylene hot-melt adhesive strip; 7. Steel belt armor layer; 8. Second waterproof sealing layer; 801. Second aluminum-plastic strip; 802. Second polyethylene hot-melt adhesive strip. DETAILED DESCRIPTION

[0019] It is easy to understand that according to the technical solution of the present invention, without changing the essential spirit of the present invention, a person skilled in the art can propose a variety of interchangeable structural modes and implementation modes. Therefore, the following specific embodiments and drawings are only exemplary descriptions of the technical solution of the present invention and should not be regarded as the entire invention or as a limitation or restriction of the technical solution of the present invention.

[0020] In existing technologies, cables used in high-voltage transmission scenarios are exposed to humid, submerged, or high-humidity environments for long periods of time, such as direct underground burial and submarine laying. Moisture intrusion can cause insulation aging, degradation of electrical performance, and even short circuit failures. Traditional water-blocking cables often use a single water-blocking mechanism, relying solely on physical water-blocking materials or chemical plugging materials. This makes it difficult to quickly block the water diffusion path when the outer protective layer is damaged. Existing solutions have a low degree of prefabrication, making them inflexible for installation at the construction site. They also lack mechanical strength and are easily damaged by external forces in complex laying environments, losing their water-blocking function.

[0021] To address these issues, researchers observed that existing water-blocking structures struggled to balance immediate response with long-term protection. Analyzing water penetration pathways, they identified the need for a multi-layered barrier system. Considering ease of construction, they proposed a design combining prefabricated components with active repair. To address weaknesses in mechanical protection, they conceived the concept of combining a flexible water-blocking layer with a rigid armor layer to create a gradient protection structure.

[0022] Therefore, the present application proposes a technical solution including a copper core cable 1 and a prefabricated water-blocking layer 2. Figure 1 As shown, the copper-core cable 1 comprises, from the inside out, a metal conductor 101, a cross-linked polyethylene insulation layer 102, a semi-conductive shielding layer 103, a metal shielding layer 104, and a polyethylene sheath 105. The prefabricated water-blocking layer 2 comprises a prefabricated water-blocking bag 3, a prefabricated leak-proof bag 4, a water-absorbing shrink tape 5, a first waterproof sealing layer 6, a steel armor layer 7, and a second waterproof sealing layer 8. The prefabricated water-blocking bag 3 is packaged in a water-soluble polyvinyl alcohol bag containing water-blocking powder, while the prefabricated leak-proof bag 4 is filled with a liquid leak-proof agent in a plastic bag with a prefabricated pressure-resistant vent. The outer sides of both are wrapped in sequence with the water-absorbing shrink tape 5, the first waterproof sealing layer 6, the steel armor layer 7, and the second waterproof sealing layer 8.

[0023] Among them, the cross-linked polyethylene insulation layer 102 refers to a polyethylene material layer modified by a cross-linking process, which can be specifically achieved by radiation cross-linking or chemical cross-linking processes, and is used to improve insulation performance and heat resistance. The semi-conductive shielding layer 103 refers to a polymer composite material layer with conductive properties, which can be specifically achieved by carbon black-filled ethylene-vinyl acetate copolymer, and is used for uniform electric field distribution. The metal shielding layer 104 refers to an electromagnetic shielding structure composed of metal strips, which can be specifically achieved by spirally wrapping copper or aluminum strips, and is used to suppress electromagnetic interference. The polyethylene sheath 105 refers to a protective outer layer of polyethylene material, which can be specifically extruded by medium-density polyethylene and is used for foundation protection. The water-blocking powder in the prefabricated water-blocking bag 3 refers to a granular material that swells when exposed to water, which can be specifically achieved by acrylic grafted modified starch water-blocking powder, and is used to absorb infiltrated water to form a gel barrier. The leak-proof agent in the prefabricated leak-proof bag 4 refers to a liquid material that solidifies when exposed to water, which can be specifically achieved by a two-component polyurethane leak-proof agent, and is used to fill damaged areas to form a seal. The water-absorbing shrinkage tape 5 refers to a strip material that generates shrinkage force when it comes into contact with water. Specifically, it can be implemented by a high-strength polyester fiber composite water-absorbing shrinkage tape, which is used to tighten the prefabricated package and trigger the water-blocking reaction. The first waterproof sealing layer 6 refers to a composite sealing structure composed of an aluminum-plastic strip and a polyethylene hot-melt adhesive strip. Specifically, it can be implemented by spirally winding an aluminum-plastic strip and then reversely winding the hot-melt adhesive strip to form a primary waterproof barrier. The steel belt armor layer 7 refers to a spirally wound steel protective layer. Specifically, it can be implemented by wrapping a galvanized steel belt in an overlapping manner to enhance mechanical strength. The second waterproof sealing layer 8 refers to a composite sealing structure with the same structure as the first waterproof sealing layer 6, which is used to form a secondary waterproof barrier.

[0024] Specifically, the copper core cable 1 achieves basic electrical performance through a cross-linked polyethylene insulation layer 102 and a multi-layer shielding structure. Prefabricated water-blocking bags 3 and leak-proof bags are alternately arranged on the outer periphery of the cable. When the sheath is damaged and moisture intrudes, the water-soluble packaging bag dissolves and releases water-blocking powder, which absorbs water to form a gel barrier layer. At the same time, the pressure rupture causes the leak-proof agent to solidify after contact with moisture, thus blocking the leakage channel. The water-absorbing shrinkage tape 5 shrinks when it comes into contact with water and generates radial pressure, ensuring that the prefabricated bag fits tightly to the cable surface. The first waterproof sealing layer 6 forms a reliable sealing interface through double-layer winding of aluminum-plastic strips and hot-melt adhesive strips. The steel belt armor layer 7 provides pressure and impact protection. The second waterproof sealing layer 8 further enhances the waterproof performance. The functional layers are stacked in sequence to form a progressive protection system from flexible water blocking to rigid protection.

[0025] Compared to existing solutions, which only feature a single-layer water-blocking structure and lack active repair capabilities, this solution achieves a dual water-blocking mechanism through the synergy of prefabricated water-blocking bags (3) and leak-proof bags. While existing solutions require pre-integration of water-blocking materials within the cable, this solution utilizes an external prefabricated bag structure, allowing for on-site installation. Traditionally, the armor and waterproof layers are separated, which can easily lead to interfacial leakage. This solution achieves structural integration by alternating waterproof sealing layers with the armor layers.

[0026] Through the above technical solution, this application can quickly trigger a dual response of water blocking and leak repair when the cable sheath is damaged, effectively blocking the moisture diffusion path. The prefabricated component design facilitates on-site installation and local maintenance, reducing overall replacement costs. The multi-layer composite protective structure takes into account both flexibility and rigidity requirements, adapting to the mechanical stress in complex laying environments. The gradient sealing system significantly extends the moisture penetration path, improving the long-term reliability of the cable in humid environments.

[0027] The present application further proposes that prefabricated water-blocking bags 3 and prefabricated leak-sealing bags 4 are alternately arranged on the outside of the copper core cable 1, and the water-absorbing shrinkage tape 5 is spirally wrapped around the outside of the prefabricated water-blocking bags 3 and the prefabricated leak-sealing bags 4, and the overlapping part of each circle is greater than half of the width of the water-absorbing shrinkage tape 5.

[0028] Alternating arrangement refers to the arrangement of water-blocking and leak-sealing packages along the cable axis. This can be achieved by alternating them at regular intervals. For example, the spacing between water-blocking and leak-sealing packages can be 1.5 to 3 times the cable diameter. Spiral winding refers to continuous wrapping along the cable circumference at a constant pitch. Mechanical automation equipment can be used to achieve uniform winding. An overlap greater than one-half means that the area covered by two adjacent turns of material exceeds half the width of a single turn. For example, if the width of the water-absorbing shrinkage tape 5 is 50 mm, the overlap must exceed 25 mm.

[0029] Specifically, the alternating arrangement of water-blocking and leak-sealing packs creates a dual protection mechanism. When the cable sheath is partially damaged, the water-blocking powder rapidly absorbs infiltrated water and expands to form a gel barrier, while the leak-sealing agent solidifies and fills the crack after releasing pressure. The water-absorbing shrinkage tape 5 is spirally wound to form a continuous wrapping layer. The overlapping portion, which exceeds half the width, ensures a seamless seal when exposed to water. This wrapping method maintains a tight fit even when the cable is bent or vibrated, preventing water seepage channels caused by misalignment between layers.

[0030] Compared to existing technologies, traditional water-blocking structures often utilize a single material for continuous wrapping, failing to simultaneously activate both water-blocking and leak-proofing mechanisms upon damage. Existing absorbent tapes typically use a flat wrapping method, resulting in insufficient overlap and prone to longitudinal leakage paths. This solution achieves active sealing response in dynamic environments by alternating functional wrappings with high-overlap spiral wrapping.

[0031] Through the above-mentioned technical solution, this application can simultaneously activate water-blocking and leak-proofing functions when the cable encounters mechanical damage, effectively blocking the path of moisture diffusion along the cable's axial direction. The high-overlap wrapping method of the water-absorbing shrinkage band 5 significantly improves coverage of irregular surface defects, preventing secondary leakage caused by localized loose wrapping. This structure allows for flexible adjustment of the functional enclosure's installation position during construction, eliminating the need for factory prefabrication.

[0032] The present application further proposes that the first waterproof sealing layer 6 includes a first aluminum-plastic strip 601 and a first polyethylene hot-melt adhesive strip 602. The first aluminum-plastic strip 601 is spirally wound on the outside of the water-absorbing shrinkage strip 5, and the overlapping part of each circle is greater than half of the width of the first aluminum-plastic strip 601. The first polyethylene hot-melt adhesive strip 602 is reversely wound on the outside of the first aluminum-plastic strip 601 at the same angle, and the overlapping part of each circle is greater than 70% of the width of the first polyethylene hot-melt adhesive strip 602. The gaps between the first polyethylene hot-melt adhesive strips 602 are sealed by hot melt fusion.

[0033] Among them, the first aluminum-plastic strip 601 refers to a strip material formed by a composite of aluminum foil and plastic, and can be specifically implemented by using an aluminum foil and polyethylene composite laminate material, wherein the metal layer can block moisture penetration, and the plastic layer provides flexibility. This structure forms a physical barrier layer when spirally wound, and the width of the overlapping part can be set to 60%-80% of the strip width, for example, and the sealing is enhanced by tight coverage between layers. Among them, the first polyethylene hot-melt adhesive strip 602 refers to a hot-melt adhesive material with polyethylene as the base material, and can be specifically implemented by using a blend of low-density polyethylene and a tackifying resin, which generates flow to fill the gap after heating. The cross-covering structure formed by reverse winding can make up for the weak area at the joint of the aluminum-plastic strip, and the overlapping part can be set to 70%-90% of the strip width, for example, and the gap is eliminated by hot-melt fusion to form a continuous sealing layer.

[0034] Specifically, when the first aluminum-plastic strip 601 is spirally wound, adjacent turns form overlapping areas of width—for example, an overlap of at least half the strip width—to ensure that there are no continuous gaps at the longitudinal seams. Subsequently, the first polyethylene hot-melt adhesive strip 602 is wound with the same pitch but in the opposite direction, its coverage area forming an interlaced grid structure with the aluminum-plastic strip. Under heating conditions, the hot-melt adhesive melts and penetrates into the gaps between the aluminum-plastic strips, solidifying to form a seamless composite sealing layer. This combination of the rigid barrier of the aluminum-plastic layer and the flexible filling of the hot-melt adhesive can accommodate deformation when the cable is bent or compressed, maintaining the integrity of the seal.

[0035] Compared with existing technologies, traditional waterproofing layers often use a single layer of wrapped aluminum-plastic tape or asphalt-coated materials, which can lead to water seepage at joints and brittle cracking. This solution utilizes a bidirectional wrapping structure and a hot-melt fusion process to create a complementary sealing mechanism between the aluminum-plastic layer and the hot-melt adhesive layer. Even under mechanical stress, the hot-melt adhesive can compensate for deformation and maintain a seal.

[0036] Through the above technical solution, the present application solves the technical problem of easy water seepage at the joints of a single material layer, realizes the continuous coverage and self-repairing ability of the waterproof sealing layer, can effectively prevent moisture from penetrating into the steel belt armor layer 7, reduces the risk of moisture in the internal insulation layer of the cable, and at the same time improves the durability of the sealing structure in complex laying environments.

[0037] The present application further proposes that the gaps between the first polyethylene hot melt adhesive strips 602 are sealed by hot melt fusion.

[0038] Hot-melt fusion sealing refers to the process of melting the surface of hot-melt adhesive strips by heating them and bonding them together, forming a seamless, continuous sealing layer. This can be achieved by heating the wrapped adhesive strips using a hot air gun, infrared heating device, or electric hot roller. This process eliminates tiny gaps between the strips and prevents moisture from invading the internal structure through the interlayer gaps. The first polyethylene hot-melt adhesive strip 602 is a strip of material made from a polyethylene substrate and hot-melt adhesive. This can be achieved by combining the polyethylene substrate with an ethylene-vinyl acetate copolymer adhesive layer through a co-extrusion process. Upon heating, the adhesive layer melts and flows, and upon cooling, forms a dense bond with adjacent adhesive strips.

[0039] Specifically, during the construction of the waterproof sealing layer of the high-voltage cable, the first polyethylene hot-melt adhesive strip 602 is covered on the outside of the aluminum-plastic strip in a reverse spiral winding manner. After the strip winding is completed, heat is applied to the surface of the strip through an external heat source to soften the surface hot-melt adhesive and cause it to melt and flow. The molten hot-melt adhesive fills the gaps between adjacent strips and forms a chemical bond with the surface of the aluminum-plastic strip. After cooling and solidification, the interface between the strips is completely fused into a continuous whole, forming a sealing barrier with no penetration path. This process is particularly suitable for cable bending parts or joint areas, and can effectively deal with the problem of interlayer gap expansion caused by mechanical deformation.

[0040] Compared with existing technologies, traditional cable waterproofing layers often rely solely on tape wrapping. The overlapped tape joints rely solely on physical compression to achieve a seal, which can easily develop microcracks due to long-term thermal expansion and contraction or external forces. This solution, however, uses a hot-melt fusion process to transform the tape interface into a chemically bonded state. This not only eliminates the initial overlap gap during wrapping, but also significantly improves the interfacial bonding strength and deformation resistance, making the integrity of the waterproof seal independent of external mechanical constraints.

[0041] Through the above technical solution, the present application can achieve gapless sealing of the waterproof sealing layer throughout its entire life cycle, preventing moisture from penetrating into the internal structure of the cable along the lap joints of the rubber strips. It is especially suitable for scenarios prone to local deformation such as submarine cable joints and underground direct buried sections, and significantly reduces the risk of insulation performance degradation caused by sealing failure.

[0042] The present application further proposes that the steel belt armor layer 7 is spirally wound on the outside of the first waterproof sealing layer 6, and the overlap width of the steel belt armor layer 7 is greater than 20 mm.

[0043] The steel strip armor layer 7 refers to a mechanical protective structure formed by metal steel strips, specifically galvanized or alloy steel strips. Its spiral winding pattern evenly distributes external stress. An overlap width greater than 20 mm refers to the lateral dimension of the overlapped area between adjacent steel strip edges, achieved, for example, by controlling the ratio of the winding equipment's feed speed to the steel strip width. This dimensioning ensures seamless coverage of the steel strip layers, preventing localized stress concentration that could lead to protective failure.

[0044] Specifically, the steel belt armor layer 7 is wrapped around the outside of the first waterproof sealing layer 6 using a spiral winding process. During the winding process, the overlap area of ​​adjacent steel belt edges is controlled to be greater than 20mm. This overlap width allows the steel belt layers to form a continuous and uniform metal protective shell. When the cable is subjected to soil pressure, rock compression, or construction traction, the steel belt layer can effectively distribute the mechanical load and prevent puncture or deformation of the waterproof structure. For example, in submarine laying scenarios, the high overlap of the steel belt layer can resist the impact of ocean currents and submarine biological erosion, preventing cracks in the protective layer that could lead to water infiltration.

[0045] Compared with existing technologies, traditional armor layers often use straight overlap or low-overlap winding methods, with overlap widths typically less than 10mm, which can easily create weak points at bends. This solution, by increasing the overlap width, allows the steel belt layer to maintain structural integrity under complex stress conditions, significantly reducing the risk of armor cracking, especially when the cable passes through rocky geological areas.

[0046] Through the above technical solution, this application enhances the compression and impact resistance of the cable's outer protective layer, effectively preventing damage to the internal waterproof structure caused by external mechanical damage. In tunnel laying scenarios, this design can prevent construction equipment from colliding and causing cracks in the armor layer, and prevent moisture from invading the insulation layer through damaged areas and causing short circuits, thereby ensuring the long-term stable operation of the cable in humid environments.

[0047] The present application further proposes that the second waterproof sealing layer 8 includes a second aluminum-plastic strip 801 and a second polyethylene hot-melt adhesive strip 802. The second aluminum-plastic strip 801 is spirally wound on the outside of the steel belt armor layer 7, and the overlapping part of each turn is greater than half of the width of the second aluminum-plastic strip 801. The second polyethylene hot-melt adhesive strip 802 is reversely wound on the outside of the second aluminum-plastic strip 801 at the same angle, and the overlapping part of each turn is greater than 70% of the width of the second polyethylene hot-melt adhesive strip 802.

[0048] The second aluminum-plastic strip 801 is a strip-shaped material formed by combining aluminum foil and plastic, specifically aluminum foil and polyethylene composite laminate. It is spirally wound to form a continuous physical water barrier, with an overlap exceeding half to ensure seamless gaps between adjacent strips. The second polyethylene hot-melt adhesive strip 802 is a hot-melt adhesive strip based on polyethylene, specifically low-density polyethylene and a tackifying resin blended and extruded. It is reverse-wound to form an interlaced covering structure with the aluminum-plastic strip, filling the gaps between the strips through hot-melt fusion. An overlap exceeding 70% enhances sealing continuity.

[0049] Specifically, the second aluminum-plastic strip 801 tightly wraps around the steel armor layer 7 in a spiral pattern, with the overlap between adjacent turns exceeding 50% of the strip's width, forming a primary waterproof seal. A second polyethylene hot-melt adhesive strip 802 is then reverse-wound around the surface of the aluminum-plastic strip at the same pitch. A hot-melt process bonds the adhesive strip to the surface, with the overlap exceeding 70% of its width. After melting, a seamless seal is formed. This dual sealing mechanism effectively enhances overall waterproofing performance, with the aluminum-plastic layer providing rigid support and physical isolation, while the hot-melt adhesive fills the potential water seepage path at the joints.

[0050] Compared to existing technologies, traditional waterproof layers often use a single layer of aluminum-plastic tape or hot-melt tape. The aluminum-plastic tape's seams are prone to water seepage channels, while the hot-melt tape lacks rigid support and is prone to cracking under mechanical stress. This solution uses reversely wound aluminum-plastic tape and hot-melt adhesive strips to form a complementary structure. The high strength of the aluminum-plastic strips resists external pressure, while the plasticity of the hot-melt adhesive strips fills microscopic gaps. The synergistic effect of these two ensures a sealing layer with both mechanical strength and waterproof reliability.

[0051] Through the above technical solution, the present application constructs a composite waterproof sealing system outside the steel belt armor layer 7. The bidirectional winding of the aluminum-plastic strip and the hot-melt adhesive strip significantly reduces the possibility of moisture penetration in the axial or radial direction, especially in high humidity or water immersion environments. Even if the outer layer of protection is partially damaged, the inner layer staggered sealing structure can still maintain an effective water-blocking function, thereby extending the service life of the cable under complex working conditions.

[0052] The present application further proposes that the gaps between the second polyethylene hot melt adhesive strips 802 are sealed by hot melt fusion.

[0053] The second polyethylene hot-melt adhesive strip 802 is a thermoplastic adhesive material based on polyethylene. Specifically, it can be prepared into a strip-like structure using an extrusion molding process and hot-melt bonded to form a continuous sealing layer. This material melts and flows upon heating, filling the gaps between adjacent strips. Hot-melt fusion sealing involves heating to soften the surface of the strips and allow them to penetrate each other, forming a seamless sealing interface upon cooling. Specifically, localized heating can be achieved using a hot air gun or infrared heating device, melting the edges of the strips and bonding them to adjacent strips.

[0054] Specifically, after wrapping the second aluminum-plastic strip 801 around the outer side of the steel armor layer 7, a second polyethylene hot-melt adhesive strip 802 is spirally wrapped in the opposite direction. Heat is applied to melt the contact surfaces of the adhesive strips, causing them to fuse together, eliminating any longitudinal or transverse gaps created during the wrapping process. During cooling, the melted adhesive strips form a composite sealing layer with the aluminum-plastic strips, blocking external moisture from invading the steel layer or internal structure through these gaps.

[0055] Compared with existing technologies, traditional cable waterproofing layers often use overlapping tape or sealant coatings. These joints are prone to microcracks due to mechanical stress, and there is a risk of shrinkage and cracking after the sealant cures. This solution uses hot-melt fusion to form an integrated, seamless sealing structure between the strips, eliminating leakage caused by loose joints or material shrinkage.

[0056] Through the above technical solution, the present application can effectively prevent the waterproof sealing layer outside the steel tape armor layer 7 from losing its water-blocking function due to the presence of gaps, preventing external moisture from invading the interior of the cable through the unsealed gaps, causing corrosion of the metal shielding layer 104 or degradation of its insulation performance. This sealing method can maintain long-term and stable waterproofing in complex laying environments, reducing the maintenance requirements caused by sealing failure.

[0057] The present application further proposes that the water-blocking powder in the prefabricated water-blocking package 3 is one of acrylic acid grafted modified starch water-blocking powder, ethyl cellulose cladding water-blocking powder and sodium carboxymethyl cellulose water-blocking powder.

[0058] Among them, acrylic acid grafted modified starch water-blocking powder refers to a super absorbent material formed by chemically grafting acrylic acid monomers into starch molecular chains. Specifically, it can be achieved by free radical polymerization of starch and acrylic acid under the action of an initiator. After it comes into contact with water, it forms a three-dimensional network structure through hydrogen bonding between molecular chains, which rapidly absorbs water and expands, thereby filling the internal gaps of the cable and blocking the moisture diffusion path. Ethyl cellulose coated water-blocking powder refers to a slow-release water-blocking material with ethyl cellulose as the coating layer. Specifically, it can be achieved by spray drying to coat the surface of water-blocking particles with ethyl cellulose solution. It gradually releases the water-blocking component through the slow dissolution of the coating layer, continuously inhibiting moisture penetration during long-term operation of the cable. Sodium carboxymethyl cellulose water-blocking powder refers to a sodium salt of cellulose modified by carboxymethylation. Specifically, it can be prepared by reacting alkali cellulose with sodium chloroacetate. After it comes into contact with water, it ionizes the carboxylic acid group to form a high-viscosity gel layer, effectively preventing liquid water from migrating longitudinally along the cable.

[0059] Specifically, when the prefabricated water-blocking package 3 is damaged by external forces on the cable, its polyvinyl alcohol water-soluble packaging dissolves in water, releasing the water-blocking powder inside. For example, if the cable sheath is damaged during submarine laying, the acrylic acid-grafted modified starch water-blocking powder quickly absorbs the infiltrated water and expands to form a physical barrier. In direct underground burial environments, if there is continuous water seepage, the ethyl cellulose coating water-blocking powder maintains its water-blocking effect through a slow-release mechanism. In the high humidity environment of tunnels, the sodium carboxymethyl cellulose water-blocking powder quickly seals micro-leakage channels through gelation. Therefore, different water-blocking powders can be selected according to actual working conditions, forming multiple water-blocking defense lines through chemical adsorption, physical expansion, or viscosity increase.

[0060] Compared to existing technologies, traditional water-blocking cables often use a single water-blocking material, such as bentonite or silica gel particles. Their water-blocking efficiency is limited by the material's properties and cannot adapt to complex operating conditions. This solution, however, offers three water-blocking powders designed specifically for transient high-flow water seepage, long-term trace water seepage, and high-humidity environments. Through chemical modification and structural optimization, they achieve differentiated water-blocking responses, significantly improving the water-blocking layer's adaptability to environmental changes.

[0061] Through the above technical solution, the present application can trigger corresponding water-blocking mechanisms based on the type of water-blocking powder when the cable encounters different water intrusion scenarios. For example, acrylic acid grafted modified starch water-blocking powder can achieve rapid blocking in seconds in the event of sudden water seepage, ethyl cellulose coated water-blocking powder can maintain effective barrier effect for over ten years in continuous leakage, and sodium carboxymethyl cellulose water-blocking powder prevents water capillary diffusion through high-viscosity gel at cable bends. This solves the technical deficiency of traditional single water-blocking materials in being unable to achieve both rapid response and long-term protection, significantly reducing the risk of insulation aging caused by water penetration.

[0062] The present application further proposes that the leak-proof agent in the leak-proof bag adopts one of a two-component polyurethane leak-proof agent, an organosilicon-modified epoxy resin leak-proof agent and a one-component moisture-curing silicone rubber leak-proof agent.

[0063] Among them, a two-component polyurethane leak sealant refers to a liquid material that undergoes a cross-linking reaction after mixing a prepolymer and a curing agent. Specifically, it can be achieved by combining an isocyanate prepolymer with a polyol curing agent. It forms an elastic sealing layer through a chemical reaction and is suitable for scenarios that require rapid curing. A silicone-modified epoxy resin leak sealant refers to a composite material that introduces silicone segments into an epoxy resin matrix. Specifically, it can be achieved by modifying epoxy resin with a silane coupling agent. It has both the high adhesion of epoxy resin and the water resistance of silicone, and is suitable for high temperature and high humidity environments. A single-component moisture-curing silicone rubber leak sealant refers to a silicone rubber material that induces cross-linking by absorbing ambient moisture. Specifically, it can be achieved by combining end-hydroxyl polydimethylsiloxane with a cross-linking agent. It can self-cure when exposed to moisture without the need for mixing operations, and is suitable for small spaces or complex construction conditions.

[0064] Specifically, when the outer protective layer of the cable is damaged, allowing moisture to intrude, the plastic packaging of the prefabricated leak-proof package 4 ruptures due to pressure, releasing the liquid leak-proof agent inside. The leak-proof agent fills the damaged area under the action of moisture or mechanical extrusion, and forms a dense solidified layer through chemical reaction or moisture contact, blocking the moisture diffusion path. For example, a two-component polyurethane leak-proof agent quickly cross-links after mixing to form an elastic seal, while a single-component moisture-curing silicone rubber leak-proof agent absorbs ambient moisture to form a siloxane network structure, covering the gap between the metal shielding layer 104 and the polyethylene sheath 105.

[0065] In some specific embodiments, the choice of leak-proof agent can be adjusted according to the installation environment: for example, a silicone-modified epoxy resin leak-proof agent can be used for submarine cables to resist high pressure and salt spray corrosion, while a single-component moisture-curing silicone rubber leak-proof agent can be used for underground direct-buried cables to adapt to changes in soil moisture.

[0066] Compared to existing technologies, traditional leak-proof materials typically use only a single type of resin or rubber, lacking the flexibility to adapt to varying environmental conditions. This solution, however, offers three leak-proofing agents with fast-curing, high-temperature resistance, or self-triggering properties. These agents address various failure modes encountered during cable installation, including mechanical shock, chemical corrosion, and humidity fluctuations, significantly improving leak-proofing response speed and sealing reliability.

[0067] Through the above technical solution, the present application can quickly trigger the release of the leak-proof agent when the cable sheath is damaged, and form a targeted sealing layer through different curing mechanisms, effectively preventing moisture from diffusing along the gap between the metal shielding layer 104 and the insulation layer, avoiding the overall insulation performance degradation due to local leakage, thereby extending the service life of the cable in a humid environment.

[0068] The present application further proposes that the water-absorbing shrinkage belt 5 adopts one of a high-strength polyester fiber composite water-absorbing shrinkage belt, a hydrogel fiber shrinkage belt and a shape memory polymer shrinkage belt.

[0069] Among them, the high-strength polyester fiber composite water-absorbing shrinkage tape refers to a strip material composed of a polyester fiber base material and a water-absorbing resin. Specifically, this can be achieved by coating the surface of the polyester fiber woven layer with a neutral acrylate and hydroxyalkyl acrylate copolymer. When this material comes into contact with water, the resin absorbs water and expands to form a dense water-blocking layer, while the fiber base material maintains its structural strength. Among them, the hydrogel fiber shrinkage tape refers to a wet spinning process in which a polyacrylamide / acrylic acid copolymer spinning solution is extruded through a spinneret and coagulated in a coagulation bath to obtain hydrogel fibers, which are then woven into a tape. After absorbing water, the hydrogel volume expands and squeezes the fiber grid to generate radial shrinkage force. Among them, the shape memory polymer shrinkage tape refers to a polymer material tape with temperature-responsive properties. Specifically, it can be a ribbon structure extruded from a polynorbornene-based shape memory polymer. This material generates shrinkage stress through changes in molecular chain conformation under specific temperature conditions.

[0070] Specifically, when the cable's outer protective structure is damaged and moisture intrudes, the water-absorbing shrink tape 5 undergoes a physical or chemical response upon contact with the water. For example, the high-strength polyester fiber composite water-absorbing shrink tape rapidly expands to fill gaps while maintaining the tensile strength of the fiber base material; the hydrogel fiber shrink tape expands to form a circumferential seal; and the shape memory polymer shrink tape triggers a shape memory effect upon contact with water, actively shrinking and compressing the damaged area. All three materials can trigger a water-blocking mechanism under different operating conditions, creating a dynamic, adaptive sealing effect.

[0071] Compared to existing technologies, traditional water-blocking structures often utilize a single water-swelling material, making it difficult to achieve a balanced balance between mechanical strength and water-blocking efficiency. For example, ordinary absorbent cotton tapes easily deform and fail under pressure, while rubber shrink tapes lack the ability to absorb and expand. This solution, through the synergy of material combination and functional synergy, achieves rapid water absorption response while maintaining mechanical load-bearing capacity. This solution is particularly suitable for complex installation environments subject to mechanical vibration or temperature fluctuations.

[0072] Through the above technical solution, the present application can form a three-dimensional water-blocking barrier through multiple action mechanisms when the cable sheath is damaged, effectively blocking the axial diffusion path of moisture along the cable, reducing the risk of moisture in the insulation layer, and at the same time ensuring the integrity of the water-blocking structure under stress conditions, reducing secondary leakage caused by mechanical damage.

[0073] The above description is merely an embodiment of the present application and is not intended to limit the scope of protection of the present application. For those skilled in the art, various modifications and variations of the present application are possible. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present application shall be included in the scope of protection of the present application.

Claims

1. A prefabricated water-blocking copper core high-voltage cable, characterized in that: include: A copper core cable and a prefabricated water-blocking layer, the copper core cable includes a metal conductor, the metal conductor is wrapped with a cross-linked polyethylene insulation layer, the cross-linked polyethylene insulation layer is wrapped with a semi-conductive shielding layer on the outside, the semi-conductive shielding layer is wrapped with a metal shielding layer on the outside, and the metal shielding layer is wrapped with a polyethylene sheath; the prefabricated water-blocking layer includes a prefabricated water-blocking bag and a prefabricated leak-proof bag, the prefabricated water-blocking bag and the prefabricated leak-proof bag are wrapped around the outside of the copper core cable, the prefabricated water-blocking bag adopts a polyvinyl alcohol water-soluble packaging bag, the interior of the packaging bag is filled with water-blocking powder, the prefabricated leak-proof bag adopts a plastic packaging bag with a prefabricated pressure rupture, the interior of the packaging bag is filled with liquid leak-proof agent, the prefabricated water-blocking bag and the prefabricated leak-proof bag are wrapped with a water-absorbing shrinkage tape on the outside, the water-absorbing shrinkage tape is wrapped with a first waterproof sealing layer, the first waterproof sealing layer is wrapped with a steel belt armor layer, and the steel belt armor layer is wrapped with a second waterproof sealing layer.

2. The prefabricated water-blocking copper core high-voltage cable according to claim 1, characterized in that: The prefabricated water-blocking bag and the prefabricated leak-sealing bag are alternately arranged on the outside of the copper core cable, and the water-absorbing shrinkage belt is spirally wound around the outside of the prefabricated water-blocking bag and the prefabricated leak-sealing bag, and the overlapping part of each circle is greater than half of the width of the water-absorbing shrinkage belt.

3. The prefabricated water-blocking copper core high-voltage cable according to claim 1, characterized in that: The first waterproof sealing layer includes a first aluminum-plastic strip and a first polyethylene hot-melt adhesive strip. The first aluminum-plastic strip is spirally wound on the outside of the water-absorbing shrinkage strip, and the overlapping part of each turn is greater than half of the width of the first aluminum-plastic strip. The first polyethylene hot-melt adhesive strip is reversely wound on the outside of the first aluminum-plastic strip at the same angle, and the overlapping part of each turn is greater than 70% of the width of the first polyethylene hot-melt adhesive strip.

4. The prefabricated water-blocking copper core high-voltage cable according to claim 3, characterized in that: The gaps between the first polyethylene hot melt adhesive strips are sealed by hot melting.

5. The prefabricated water-blocking copper core high-voltage cable according to claim 1, characterized in that: The steel belt armor layer is spirally wound on the outside of the first waterproof sealing layer, and the overlapping width of the steel belt armor layer is greater than 20 mm.

6. The prefabricated water-blocking copper core high-voltage cable according to claim 1, characterized in that: The second waterproof sealing layer includes a second aluminum-plastic strip and a second polyethylene hot-melt adhesive strip. The second aluminum-plastic strip is spirally wound on the outside of the steel belt armor layer, and the overlapping part of each turn is greater than half of the width of the second aluminum-plastic strip. The second polyethylene hot-melt adhesive strip is reversely wound on the outside of the second aluminum-plastic strip at the same angle, and the overlapping part of each turn is greater than 70% of the width of the second polyethylene hot-melt adhesive strip.

7. The prefabricated water-blocking copper core high-voltage cable according to claim 6, characterized in that: The gaps between the second polyethylene hot melt adhesive strips are sealed by hot melting.

8. The prefabricated water-blocking copper core high-voltage cable according to claim 1, characterized in that: The water-blocking powder in the prefabricated water-blocking package is one of acrylic acid grafted modified starch water-blocking powder, ethyl cellulose cladding water-blocking powder and sodium carboxymethyl cellulose water-blocking powder.

9. The prefabricated water-blocking copper core high-voltage cable according to claim 1, characterized in that: The leak-proof agent in the leak-proof bag is one of a two-component polyurethane leak-proof agent, an organosilicon-modified epoxy resin leak-proof agent and a one-component moisture-curing silicone rubber leak-proof agent.

10. The prefabricated water-blocking copper core high-voltage cable according to claim 1, characterized in that: The water-absorbing shrinkage belt is one of a polyester fiber composite water-absorbing shrinkage belt, a hydrogel fiber shrinkage belt and a shape memory polymer shrinkage belt.

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