Pre-embedded insulation protection cable for smart power grid

Abstract

The invention relates to the technical field of insulation protection cables, and discloses an intelligent power grid pre-embedded insulation protection cable which comprises an insulation sheath, a wrapping tape structure is arranged in the insulation sheath, a first armoring steel tape is arranged in the wrapping tape structure, a second armoring steel tape is arranged in the first armoring steel tape, and the second armoring steel tape is arranged in the second armoring steel tape. A movable hole is formed in the surface of the second armoring steel belt, the first armoring steel belt and the second armoring steel belt are made of elastic materials, and the outer surface of the first armoring steel belt is wrapped with a traction spring. According to the pre-embedded insulation protection cable for the smart power grid, through a dual-steel-tape armoring structure which is coaxially attached and in directional sliding fit and in cooperation with the traction and compression design of the dual-strand pre-embedded wires, controllable switching between the cable laying state and the cable operation state is achieved, the armoring dislocation gap state is kept in the laying stage so as to reduce the pipe penetrating construction resistance, and the construction efficiency is improved. And after the cable is laid in place, the cable can be pulled and compressed to form a totally-closed seamless tubular armor, so that the inherent contradiction that laying convenience and protection performance cannot be considered in the traditional armor is thoroughly solved.

Description

A smart grid pre-embedded insulated protective cable Technical Field

[0001] This invention relates to the field of insulated protective cable technology, and in particular to a smart grid pre-embedded insulated protective cable. Background Technology

[0002] With the comprehensive advancement of new power system construction and the deep popularization of smart grids, pre-buried insulated protective cables, as core infrastructure for power transmission and signal measurement and control in scenarios such as urban underground integrated pipe corridors, urban and rural power grid upgrades and renovations, distributed new energy grid connection, and power supply for industrial and mining enterprises, are experiencing continuous expansion in application scale and coverage. The high reliability and high security requirements of smart grids dictate that pre-buried cables must serve in complex underground environments for extended periods, simultaneously withstanding multiple external stresses such as soil acid and alkali corrosion, geological subsidence and deformation, heavy-load crushing and impact, and rodent and ant biological damage. This places extremely high demands on the mechanical protection performance, electrical insulation stability, long-term service life, and ease of construction and maintenance of the cables. The performance of the cable protection structure directly determines the safe and stable operation level of the smart grid transmission and distribution system.

[0003] The current core technological bottleneck of pre-buried cables lies in the fact that the armored protective structure cannot simultaneously achieve both ease of installation and reliable protection throughout the entire life cycle, making it difficult to adapt to the diverse chemical conditions and long-term operation and maintenance requirements of smart grid pre-buried scenarios. In existing technologies, pre-buried cables generally use fixed-lap wrapped steel tape armor as the core protective structure. This structure is finalized during the factory production stage, requiring sufficient steel tape overlap to ensure mechanical protection performance. This directly leads to an increase in the overall outer diameter of the cable, resulting in high frictional resistance during conduit laying. During small-radius bending construction, problems such as steel tape arching, warping, and even puncturing the outer sheath easily occur, failing to achieve a balance between ease of installation and protective performance. Furthermore, gaps and suspended areas easily exist between the fixed-lapped steel tape and the inner sheath of the cable, which can lead to problems such as cable dragging during installation, thermal expansion and contraction during operation, and geological conditions. Under conditions such as settlement and deformation, steel strips are prone to loosening, slippage, and lap failure, leading to a continuous decrease in the tightness of the armor layer covering the cable core, unstable mechanical protection effect, and in severe cases, complete loss of protective capability. In addition, the fixed armor structure cannot flexibly adjust the covering state according to the geological conditions of the site. When the armor becomes loose, corroded and damaged after long-term operation, it cannot be repaired and its performance compensated in the underground confined environment. It can only be dealt with by excavating the entire section and replacing the cable. The operation and maintenance cost throughout the entire life cycle is extremely high, and it cannot meet the core requirements of smart grid for the full life cycle status management of cables. Summary of the Invention

[0004] The technical problem to be solved by this invention is that the existing technology has the disadvantage of poor armor adhesion due to loose armor. To address this, we propose a smart grid pre-embedded insulated protective cable.

[0005] To achieve the above objectives, this application adopts the following technical solution: a smart grid pre-embedded insulated protective cable, comprising an insulating outer sheath, an inner wrapping tape structure, an armored steel tape I inside the wrapping tape structure, an armored steel tape II inside the armored steel tape I, movable holes on the surface of the armored steel tape II, the armored steel tape I and the armored steel tape II being made of elastic material, a tension spring wrapped around the outer surface of the armored steel tape I for providing radial support, the outer surface of the armored steel tape I being wound with the wrapping tape structure, and a double-strand pre-embedded wire on one side of the armored steel tape I and the armored steel tape II, the double-strand pre-embedded wire being divided into two strands, one strand being located on the outer side of the armored steel tape I and the armored steel tape II, and the other strand being located on the inner side of the armored steel tape I and the armored steel tape II.

[0006] Preferably, the cable core is disposed inside the insulating outer sheath, and the cable core is wrapped by a multi-layer structure, wherein the insulating outer sheath is included as the outermost layer of the cable core.

[0007] Preferably, the outer surface of the cable core is wrapped with an inner protective layer, the outer surface of the inner protective layer is provided with a support layer, a protective sleeve is provided on the side of the support layer away from the inner protective layer, the protective sleeve is wrapped around the outer surface of the inner protective layer, and a filler is filled between the protective sleeve and the inner protective layer.

[0008] Preferably, the outer surface of the second armored steel strip is provided with a movable hole, and the inner wall of the first armored steel strip is provided with a protrusion. The protrusion is embedded in the interior of the movable hole, and the first armored steel strip and the second armored steel strip are connected by the protrusion sliding inside the movable hole.

[0009] Preferably, a pressure ring is embedded inside the insulating outer sheath, and the double-strand pre-embedded wire passes through the inside of the pressure ring. The double-strand pre-embedded wire is used to tighten the armored steel strip one and the armored steel strip two, and the pressure ring is used to restrict the movement of one side of the armored steel strip one and the armored steel strip two.

[0010] Preferably, the cable core is wrapped from the inner layer to the outer layer with an inner protective layer, a support layer, a filler, a protective sleeve, a second armored steel strip, a first armored steel strip, a tension spring, a wrapping tape structure, and an insulating outer sheath.

[0011] Preferably, the support layer divides the protective sleeve and the inner protective layer into multiple spaces, and the space formed between each two sets of support layers is filled with filler material.

[0012] Preferably, the filler adopts a prefabricated fan-shaped columnar structure and is thermally bonded to the inner protective layer and the support layer to form an integrated coaxial filling structure.

[0013] Preferably, the filler is composed of polyether polyurethane, silica, halogen-free flame-retardant ammonium polyphosphate, maleic anhydride-grafted polyethylene wax, ultra-high molecular weight polyethylene micro powder, carbon nanotube varistor conductive filler, hindered amine light stabilizer, and antioxidant 1010.

[0014] Preferably, the filler is prepared using a gradient density closed-cell foaming process, with an inner layer being a high-density, low-foaming layer and an outer layer being a low-density, high-foaming layer, and a nano-self-lubricating film layer composited on the outer surface.

[0015] The technical effects and advantages of this invention are as follows:

[0016] In this invention, a double steel strip armor structure with coaxial bonding and directional sliding fit, combined with a double-strand pre-embedded wire pulling and compression design, enables controllable switching between cable laying and operation states. During the laying stage, the armor misalignment gap is maintained to reduce the resistance of pipe installation. After laying, it can be pulled and compressed to form a fully enclosed seamless tubular armor, completely solving the inherent contradiction between the convenience of laying and the protective performance of traditional armor. Secondly, the pre-embedded pulling structure enables the armor performance to be adjusted throughout its entire life cycle for multiple tightening compensations, completely solving the industry pain point of long-term failure and irreparable damage of traditional pre-embedded armor, significantly reducing the maintenance cost of the cable throughout its entire life cycle, and comprehensively improving the environmental adaptability, operational safety and long-term service life of the pre-embedded cable. Attached Figure Description

[0017] The disclosure of this 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 this invention. In the drawings, the same reference numerals are used to refer to the same parts:

[0018] Figure 1 is a three-dimensional structural schematic diagram of the present invention; Figure 2 is a structural schematic diagram of the protective sleeve and cable core of the present invention; Figure 3 is a structural schematic diagram of the armored steel tape I in the tightened state of the present invention; Figure 4 is a structural schematic diagram of the wrapping tape structure and armored steel tape I of the present invention; Figure 5 is a cross-sectional structural schematic diagram of the insulation outer sheath of the present invention; Figure 6 is a structural schematic diagram of the support layer and filler of the present invention; Figure 7 is an exploded structural schematic diagram of the present invention; Figure 8 is an initial state schematic diagram of armored steel tape I and armored steel tape II of the present invention; Figure 9 is an exploded structural schematic diagram of armored steel tape I and armored steel tape II of the present invention.

[0019] Legend: 1. Insulation sheath; 2. Wrapping tape structure; 3. Armored steel tape one; 4. Double-strand embedded wire; 5. Protective sleeve; 6. Inner protective layer; 7. Supporting layer; 8. Filler; 9. Cable core; 10. Tension spring; 11. Armored steel tape two; 12. Movable hole; 13. Pressure ring. Detailed Implementation

[0020] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0021] Referring to Figures 1-9, the present invention provides a technical solution: a smart grid pre-embedded insulated protective cable, comprising an insulating outer sheath 1, a wrapping tape structure 2 disposed inside the insulating outer sheath 1, an armored steel tape 3 disposed inside the wrapping tape structure 2, an armored steel tape 2 11 disposed inside the armored steel tape 3, a movable hole 12 formed on the surface of the armored steel tape 2 11, a movable hole 12 formed on the outer surface of the armored steel tape 2 11, and a protrusion disposed on the inner wall of the armored steel tape 3, the protrusion being embedded in the movable hole 12. The armored steel tape 3 and the armored steel tape 2 11 are connected by sliding the protrusion within the movable hole 12.

[0022] The embedded sliding fit between the protrusion and the movable hole 12 provides directional limiting guidance for the relative movement of armor steel belt 11 and armor steel belt 2, restricting the circumferential deflection and radial misalignment of the two steel belts. This ensures that the two maintain a coaxial parallel relative movement state during tension, compression, and bending deformation, solving the industry pain points of existing adjustable armor structures, such as circumferential deflection, sliding jamming, and uneven coverage on one side. At the same time, the embedded sliding fit structure significantly reduces the frictional resistance of the relative sliding of the two steel belts, ensuring the consistency and reliability of armor adjustment.

[0023] Armored steel strip 1-3 and armored steel strip 2-11 are made of elastic material, possessing the structural rigidity, impact resistance, and compression resistance required for metal armor, as well as excellent elastic deformation capability. They can achieve precise adjustment of armor pitch through elastic compression, and can adapt to various deformations caused by cable bending, geological subsidence, and thermal expansion and contraction. This avoids the problems of arching, warping, and fatigue fracture that are prone to occur in traditional rigid steel strips, and greatly improves the long-term service stability of the armor structure.

[0024] The outer surface of the armored steel strip 3 is wrapped with a tension spring 10, which provides radial support. The outer surface of the armored steel strip 3 is also wrapped with a wrapping tape structure 2. The wrapping tape structure 2 wraps the armored steel strip 3 and the tension spring 10 in a full circumference, and performs secondary binding and shaping to further prevent the double steel strips from shifting or loosening, thereby improving the overall stability of the armored structure. At the same time, the wrapping tape structure 2 can form an isolation buffer layer between the armored structure and the outer insulation sheath 1, preventing the edges of the armored structure from scratching the insulation sheath 1 and improving the electrical safety performance of the cable.

[0025] A double-strand pre-buried wire 4 is installed on one side of armored steel strip 1 (3) and armored steel strip 2 (11). The double-strand pre-buried wire 4 consists of two strands, one of which is located on the outside of armored steel strip 1 (3) and armored steel strip 2 (11), and the other is located on the inside of armored steel strip 1 (3) and armored steel strip 2 (11). After the cable is laid in place, the armor can be adjusted and tightened simply by pulling the double-strand pre-buried wire 4 at the cable end. The operation is simple and convenient, which greatly reduces the on-site construction difficulty in underground pre-buried scenarios and is suitable for the construction needs of long-distance pre-buried cables.

[0026] An insulating outer sheath 1 has a pressure ring 13 embedded inside, and a double-strand pre-embedded wire 4 passes through the inside of the pressure ring 13. The double-strand pre-embedded wire 4 is used to tighten the armored steel tape 1 3 and the armored steel tape 2 11. The pressure ring 13 is used to restrict the movement of one side of the armored steel tape 1 3 and the armored steel tape 2 11. The cable core 9 is wrapped from the inner layer to the outer layer with an inner protective layer 6, a support layer 7, a filler 8, a protective sleeve 5, an armored steel tape 2 11, an armored steel tape 1 3, a tension spring 10, a wrapping tape structure 2 and an insulating outer sheath 1.

[0027] The cable core 9 is installed inside the insulating outer sheath 1. The cable core 9 is wrapped by a multi-layer structure, wherein the insulating outer sheath 1 is the outermost layer of the cable core 9. The outer surface of the cable core 9 is wrapped with an inner protective layer 6. A support layer 7 is provided on the outer surface of the inner protective layer 6. A protective sleeve 5 is provided on the side of the support layer 7 away from the inner protective layer 6. The protective sleeve 5 is wrapped around the outer surface of the inner protective layer 6. Filler 8 is filled between the protective sleeve 5 and the inner protective layer 6.

[0028] The support layer 7 divides the protective sleeve 5 and the inner protective layer 6 into multiple spaces. Each space between two sets of support layers 7 is filled with filler material 8. The filler material 8 adopts a prefabricated fan-shaped columnar structure and is fixed by hot-melt bonding of the inner protective layer 6 and the support layer 7 to form an integrated coaxial filling structure. The filler material 8 is composed of polyether polyurethane, silica, halogen-free flame-retardant ammonium polyphosphate, maleic anhydride grafted polyethylene wax, ultra-high molecular weight polyethylene micro powder, carbon nanotube pressure-sensitive conductive filler, hindered amine light stabilizer and antioxidant 1010. The filler material 8 is prepared by gradient density closed-cell foaming process. The inner layer is a high-density low-foaming layer and the outer layer is a low-density high-foaming layer. The outer surface is composited with a nano self-lubricating film layer.

[0029] Polyether-based polyurethane provides excellent elastic deformation capability and rebound recovery performance, adapting to cavity changes caused by armor adjustment and cable deformation; nano-silica enhances the anti-aging performance and structural strength of filler 8, preventing powdering and collapse after long-term use; halogen-free flame-retardant ammonium polyphosphate imparts excellent halogen-free flame-retardant properties to filler 8, meeting national standards for cable fire safety and improving cable operation safety; maleic anhydride-grafted polyethylene wax improves the compatibility of each component and strengthens the deformation rebound stability of filler 8; ultra-high molecular weight polyethylene micro powder reduces the friction coefficient of filler 8 surface, adapting to internal micro-deformation during armor adjustment; carbon nanotube varistor-conductive filler imparts varistor characteristics to filler 8, making the resistance value of filler 8 linearly correlated with the deformation, enabling real-time monitoring and early warning of excessive internal compression and settlement deformation of the cable, adapting to the intelligent operation and maintenance needs of smart grids; hindered amine light stabilizer and antioxidant 1010 significantly improve the hydrolysis and anti-aging performance of filler 8 in underground pre-buried environments.

[0030] The gradient density closed-cell foam structure provides stable rigidity for the cable core, preventing core displacement. The outer low-density high-foam layer, close to the protective sleeve 5, possesses excellent elastic deformation and resilience, adapting to cavity deformation and fully absorbing external impact loads while maintaining filling density without gaps or collapse. The closed-cell foam structure gives the filler 8 excellent water and moisture barrier properties, completely preventing moisture absorption and water seepage. It can prevent water vapor and corrosive media in the soil from penetrating inward, assisting in protecting the inner protective layer 6 and the cable core 9, and extending the cable's service life. The composite nano self-lubricating film layer on the outer surface can significantly reduce the frictional resistance between the filler 8 and the inner wall of the protective sleeve 5. It will not interfere with the internal micro-deformation during the sliding and compression process of the double steel tape armor, and can also reduce internal structural friction damage during cable laying and conduit installation, further improving the cable's construction convenience and long-term operational stability.

[0031] Working principle: The protection of this smart grid pre-embedded protective cable mainly comes from the cooperation between the double-strand pre-embedded wire 4 and the armored steel tape 11. In traditional cables, due to the ductility of the steel structure, the metal tape wrapping structure has poor fit with the inner sheath of the cable and is not tightly wrapped, which easily leads to gaps and suspended areas. Under bending, dragging and external force, it is easy to loosen, slip and curl up, which leads to a decrease in the tightness of the armor layer covering the cable core and unstable mechanical protection effect.

[0032] To address this issue, the fit between the armored steel tape 1 (3), the double-strand pre-embedded wire 4, and the armored steel tape 2 (11) is increased to eliminate the aforementioned defect. Specifically, the cable core 9 is encased in a multi-layered protective structure. The outermost layer is the insulation sheath 1, followed by an inner protective layer 6, a support layer 7, filler 8, a protective sleeve 5, armored steel tape 2 (11), armored steel tape 1 (3), a tension spring 10, a wrapping tape structure 2, and the insulation sheath 1. The insulation sheath 1 is primarily made of cross-linked polyethylene material. It has good cut and fire resistance. When buried underground, it can also play a certain supporting role, preventing the internal structure of the cable from becoming loose and structurally damaged due to the pressure of burial. After being protected by the insulation sheath 1, the insulation sheath 1 has a wrapping tape structure 2 inside. The wrapping tape structure 2 is a nylon strip structure with a lubricating material on its surface. The wrapping tape structure 2 is wrapped around the outer surface of the tension spring 10 and the armored steel tape 3 by a wrapping machine. After the tension spring 10 and the armored steel tape 3 are wrapped with the wrapping tape structure 2, they themselves... The structure also has higher stability. Armored steel belt 11 is installed inside armored steel belt 3, with armored steel belt 2 11 fitting against the inner wall of armored steel belt 3. The two maintain a sliding relationship. Armored steel belt 2 11 and armored steel belt 3 are connected by a movable hole 12. The protrusions on the inner wall of armored steel belt 3 are embedded in the movable hole 12 and can slide freely within it. A protective sleeve 5 is installed inside armored steel belt 2 11, and a support layer 7 is installed inside the protective sleeve 5. The support layer 7 provides protection. An inner protective layer 6 is provided on one side of the sleeve 5. The inner protective layer 6 is included on the surface of the cable core 9. The support layer 7 evenly distributes the space formed by the protective sleeve 5 and the inner protective layer 6. The support layer 7 surrounds the outer surface of the inner protective layer 6 and is integrally formed with the inner protective layer 6 by hot melting. A set of filler material 8 is filled between every two support layers 7. The filling of filler material 8 increases the internal tightness and avoids the internal structure from being too loose. In addition, filler material 8 can also play a better protective role and increase the protection effect of the cable core 9.

[0033] In the field application environment, the cable is first pre-buried at the designated location. This is done by pulling the double-strand pre-buried wire 4, which passes through the inside of the pressure ring 13, which is embedded inside the insulation sheath 1. When the double-strand pre-buried wire 4 is pulled, initially, the armored steel tape 1 3 and armored steel tape 2 11 are misaligned. As the double-strand pre-buried wire 4 is pulled, the armored steel tape 2 11 and armored steel tape 1 3 completely overlap. Then, the double-strand pre-buried wire 4 is continued to be pulled, causing the armored steel tape 1 3 and armored steel tape 2 11 to be continuously compressed. The shape and structure of the armored steel strip 21 are similar to a spring. When pulled by the double-strand pre-embedded wire 4, the gap between the armored steel strip 13 itself is reduced. When the armored steel strip 13 is completely compressed, it forms a "tubular" structure, which can better wrap the protective sleeve 5. In addition, in order to prevent the armored steel strip 13 and the armored steel strip 211 from being deformed by external extrusion, a tension spring 10 is connected to the outer surface of the armored steel strip 13. The tension spring 10 provides radial support force, which increases the protection of the inner cable core 9.

[0034] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A smart grid pre-embedded insulated protective cable, characterized in that, The device includes an insulating outer sheath, an inner wrapping tape structure, an inner armored steel strip (first type), an inner armored steel strip (second type), and movable holes on the surface of the second armored steel strip. Both the first and second armored steel strips are made of elastic material. A tension spring is wrapped around the outer surface of the first armored steel strip to provide radial support. A double-strand pre-embedded wire is located on one side of both the first and second armored steel strips. The double-strand pre-embedded wire is divided into two strands, one strand located on the outer side of both armored steel strips and the other strand located on the inner side.

2. The smart grid pre-embedded insulated protective cable according to claim 1, characterized in that: The cable core is disposed inside the insulating outer sheath, and the cable core is wrapped by a multi-layer structure, wherein the insulating outer sheath is included as the outermost layer of the cable core.

3. The smart grid pre-embedded insulated protective cable according to claim 2, characterized in that: The outer surface of the cable core is wrapped with an inner protective layer, and a support layer is provided on the outer surface of the inner protective layer. A protective sleeve is provided on the side of the support layer away from the inner protective layer. The protective sleeve is wrapped around the outer surface of the inner protective layer, and filler is used to fill the space between the protective sleeve and the inner protective layer.

4. The smart grid pre-embedded insulated protective cable according to claim 1, characterized in that: The outer surface of the second armored steel strip is provided with a movable hole, and the inner wall of the first armored steel strip is provided with a protrusion. The protrusion is embedded in the interior of the movable hole, and the first armored steel strip and the second armored steel strip are connected by the protrusion sliding inside the movable hole.

5. The smart grid pre-embedded insulated protective cable according to claim 1, characterized in that: A pressure ring is embedded inside the insulating outer sheath, and the double-strand pre-embedded wire passes through the inside of the pressure ring. The double-strand pre-embedded wire is used to tighten the armored steel belt one and the armored steel belt two, and the pressure ring is used to restrict the movement of one side of the armored steel belt one and the armored steel belt two.

6. The smart grid pre-embedded insulated protective cable according to claim 1, characterized in that: The cable core is wrapped from the innermost layer to the outermost layer with an inner protective layer, a support layer, filler, a protective sleeve, a second armored steel strip, a first armored steel strip, a tension spring, a wrapping tape structure, and an insulating outer sheath.

7. The smart grid pre-embedded insulated protective cable according to claim 1, characterized in that: The support layer divides the protective sleeve and the inner protective layer into multiple spaces, and the space formed between each pair of support layers is filled with filler material.

8. The smart grid pre-embedded insulated protective cable according to claim 7, characterized in that: The filler adopts a prefabricated fan-shaped columnar structure and is thermally bonded to the inner protective layer and the support layer to form an integrated coaxial filler structure.

9. The smart grid pre-embedded insulated protective cable according to claim 8, characterized in that: The filler is composed of polyether polyurethane, silica, halogen-free flame-retardant ammonium polyphosphate, maleic anhydride-grafted polyethylene wax, ultra-high molecular weight polyethylene micro powder, carbon nanotube varistor conductive filler, hindered amine light stabilizer, and antioxidant 1010.

10. The smart grid pre-embedded insulated protective cable according to claim 9, characterized in that: The filler is prepared using a gradient density closed-cell foaming process, with an inner layer of high density and low foaming, an outer layer of low density and high foaming, and a nano self-lubricating film layer on the outer surface.

Images