Anti-interference optical fiber monitoring crosslinked cable and forming and manufacturing method

Abstract

The invention relates to the technical field of power transmission and cable monitoring cables, in particular to an anti-interference optical fiber monitoring cross-linked cable and a forming and manufacturing method, and the cable sequentially comprises a cable core layer, a monitoring function layer, an electromagnetic shielding layer, an insulation protection layer and an outer protection layer from inside to outside; the monitoring function layer is tightly wound on the outer surface of the cable core layer in a spiral shape, the electromagnetic shielding layer is located between the monitoring function layer and the insulation protection layer, the electromagnetic shielding layer is of a multi-layer structure, the inner layer of the electromagnetic shielding layer is a permalloy belt, and the outer layer of the electromagnetic shielding layer is a tinned copper woven mesh. And a plurality of rat-proof and ant-proof composite layers are arranged on the outer side wall of the outer protective layer at intervals along the length direction of the outer protective layer. The monitoring function layer is spirally and tightly wound on the outer surface of the cable core layer, the design enables the optical fiber and the cable core layer to be tightly attached, it is ensured that the temperature change and mechanical deformation of the cable core layer can be rapidly transmitted to the optical fiber, and the problem of monitoring lag caused by gaps in a traditional loose tube structure is solved.

Description

Technical Field

[0001] This invention relates to the field of power transmission and cable monitoring technology, and in particular to an anti-interference fiber optic monitoring cross-linked cable and its molding and manufacturing method. Background Technology

[0002] In the field of modern power transmission, cross-linked cables are the core carriers for power transmission, and real-time monitoring of their operating status is crucial for power grid security.

[0003] Most existing cross-linked cables focus on improving electrical performance and anti-aging properties, lacking a systematic design for integrating monitoring functions.

[0004] Taking Chinese patent application number 202211096609.4, "A Cross-linked Polyethylene Insulated Cable and Its Preparation Method," as an example, it mainly improves anti-aging performance by optimizing the raw material formula of the cable sheath. However, it has the following drawbacks in actual production and application:

[0005] First, the structural design is not adapted to the requirements of anti-interference fiber optic monitoring. The cable consists of a cable core and a single cable sheath, without any reserved channels for fiber optic installation or electromagnetic shielding structure. If a fiber optic monitoring system is integrated, the fiber optic cable must be inserted into the gaps in the existing structure, which is prone to damage due to compression and bending, and cannot isolate external electromagnetic interference.

[0006] Second, the manufacturing process cannot achieve synchronous integration of monitoring components. The preparation process involves mixing raw materials and heating and extruding to form a mold, which only optimizes the insulation performance of the cable sheath and does not involve the collaborative process of fiber optic embedding. Adding optical fibers later requires damaging the original cable structure, which not only reduces production efficiency but also easily leads to unstable monitoring signals due to assembly errors.

[0007] Third, the reliability of monitoring and cable body coordination is insufficient during long-term operation. Although the aforementioned patent improves the anti-aging properties of the cable sheath through material improvements, it does not consider the matching of the thermal expansion coefficients of the optical fiber and the cable material. Under temperature cycling and mechanical stress, relative displacement between the optical fiber and the cable sheath is prone to occur, leading to attenuation or distortion of the monitoring signal, and failing to guarantee effective monitoring throughout the entire life cycle.

[0008] Therefore, it is necessary to design a cross-linked cable that combines anti-interference monitoring function with an adaptable manufacturing process. Summary of the Invention

[0009] To solve one of the aforementioned technical problems, the present invention provides the following technical solution: an anti-interference fiber optic monitoring cross-linked cable, wherein the cable comprises, from the inside out, a cable core layer, a monitoring functional layer, an electromagnetic shielding layer, an insulation protection layer, and an outer sheath; the cable core layer comprises multiple hybrid conductors, which are formed by spiral stranding; the monitoring functional layer is tightly wound in a spiral shape around the outer surface of the cable core layer; the electromagnetic shielding layer is located between the monitoring functional layer and the insulation protection layer; the electromagnetic shielding layer has a multi-layer structure, with an inner layer of permalloy tape and an outer layer of tin-plated copper braided mesh; and a plurality of rodent- and termite-proof composite layers are spaced apart along the length of the outer wall of the outer sheath.

[0010] Based on any of the above technical solutions, a further optimization is made to the following: the hybrid conductor includes an aluminum matrix, in which cadmium sulfide or lead selenide particles with a particle size in the range of 5-10 nanometers are dispersed.

[0011] The conductor performance is improved by the synergistic effect of cadmium sulfide or lead selenide nanoparticles with the aluminum matrix. From the perspective of material interface effect, 5-10 nanometer cadmium sulfide or lead selenide particles have a large specific surface area and form a large number of nanoscale interfaces with the matrix metal. These interfaces act as obstacles to dislocation movement.

[0012] According to the Hall-Page relation, the yield strength of a conductor increases with increasing interfacial density, effectively resisting the mechanical stress during cable stranding and laying.

[0013] Based on any of the above technical solutions, a further optimization is made to the specific preparation method of the hybrid conductor as follows:

[0014] First, heat the aluminum matrix raw material to a molten state, controlling the temperature at 700-750℃, in order to reduce its viscosity and facilitate the dispersion of nanoparticles.

[0015] Subsequently, cadmium sulfide or lead selenide nanoparticles with a particle size of 5-10 nanometers are slowly added to the molten aluminum matrix at a ratio of 0.5-1.5% by weight.

[0016] During the addition process, maintain high-speed stirring, with the stirring speed set at 1500-2000 r / min, so that the nanoparticles are initially dispersed in the aluminum melt.

[0017] After all the nanoparticles have been added, ultrasonic dispersion is initiated. The ultrasonic frequency is set to 20-40 kHz, the power to 500-1000 W, and the ultrasonic time to 15-30 minutes. (The cavitation effect generated during ultrasonic dispersion can effectively break the agglomeration of nanoparticles, allowing cadmium sulfide or lead selenide nanoparticles to be uniformly distributed in a monodisperse state within the aluminum matrix. Simultaneously, the mechanical vibration of ultrasound can promote the interdiffusion between nanoparticles and aluminum matrix atoms, enhancing the interfacial bonding force between the two.)

[0018] After high-speed stirring and ultrasonic dispersion, the resulting mixture is injected into a mold for rapid cooling. The cooling rate is controlled at 50-100℃ / s to rapidly solidify the aluminum matrix, fix the uniform dispersion of nanoparticles, and prevent nanoparticles from agglomerating or segregating.

[0019] The cooled mixture is processed into conductor wires using a continuous extrusion process;

[0020] The conductor wire is tin-plated, with the tin plating layer thickness controlled between 0.01 and 0.03 mm, to improve the conductor's oxidation resistance and electrical connection performance.

[0021] Based on any of the above technical solutions, a further optimization is made as follows: the monitoring functional layer includes a distributed optical fiber, a composite protective sleeve is sleeved on the outer wall of the distributed optical fiber, and the monitoring functional layer is tightly wrapped around the outer surface of the cable core layer.

[0022] Based on any of the above technical solutions, a further optimization is made: the composite protective sleeve includes, from the inside out, a polyurethane elastomer layer, a silicone rubber layer, and a polyvinylidene fluoride hydrophobic layer.

[0023] Based on any of the above technical solutions, the following further optimization is made: the electromagnetic shielding layer includes an inner permalloy strip and an outer tin-plated copper braided mesh. The permalloy strip is wrapped around the monitoring functional layer by a longitudinal wrapping process, and the overlap width between adjacent layers is ≥10mm. The overlap is fixed by ultrasonic welding or conductive adhesive. The tin-plated copper braided mesh covers the outer side of the permalloy strip at a braiding angle of 45°-60° with a braiding density of ≥85%.

[0024] Based on any of the above technical solutions, a further optimization is made of cross-linked polyethylene material for the insulating protective layer and polyvinyl chloride or low-smoke halogen-free flame-retardant polyolefin material for the outer protective layer.

[0025] Based on any of the above technical solutions, a further optimization is made of: annular stress dispersion structures are provided at intervals along the length of the cable core layer. The annular stress dispersion structures are made of highly elastic EPDM rubber tubes, which are tightly fitted onto the outer surface of the cable core layer to form a cylindrical annular stress dispersion structure.

[0026] The ring-shaped stress dispersion structure can absorb the stress generated by the cable under bending and tensile conditions, protect the hybrid conductor from damage, and improve the reliability and service life of the cable core layer.

[0027] The surface of the EPDM rubber capillary has several micropores that connect the inside and outside of it, and the EPDM rubber capillary is pre-filled with an appropriate amount of silicone oil.

[0028] Microporous channel structure can further improve the elasticity and buffering performance of the structure. When the cable core layer is subjected to external force and bending deformation, silicone oil has good lubrication and buffering performance. Moreover, silicone oil can play a better buffering and stress dispersion role after seeping out through microporous channels.

[0029] Based on any of the above technical solutions, a further optimization is made as follows: the anti-rodent and anti-ant composite layer includes a polyethylene film containing repellent particles inside, the polyethylene film is wrapped around the outer wall of the outer protective layer, and a fiber woven mesh is wrapped around the outside of the polyethylene film; the polyethylene film is prepared by blow molding process from high-density polyethylene, repellent particles, and antioxidants.

[0030] The method for preparing polyethylene film is as follows:

[0031] 1. Raw material preparation:

[0032] Materials: High-density polyethylene, repellent particles (particle size ≤ 50 μm), antioxidant.

[0033] Mass ratio: 85-92% high-density polyethylene, 5-10% repellent particles, and 1-3% antioxidant.

[0034] 2. Blending and granulation:

[0035] Premix: Put the raw materials into a high-speed mixer and mix for 10-15 minutes at 800-1200 r / min.

[0036] Extrusion: Twin-screw extruder temperature 160-210℃, screw speed 150-200r / min, water-cooled pelletizing (particle size 2-4mm).

[0037] 3. Blow molding: Single screw blown film machine (screw diameter 60-90mm), die temperature 180-200℃.

[0038] Steps: After plasticizing the granules, they are extruded into tube blanks with a blow-up ratio of 2-3:1 and a traction speed of 5-10m / min; cooled and shaped, with a winding tension of 10-15N.

[0039] The present invention also provides a method for molding and manufacturing an anti-interference fiber optic monitoring cross-linked cable, comprising the following steps: melting aluminum matrix raw material and adding cadmium sulfide or lead selenide nanoparticles, stirring, ultrasonically dispersing and cooling solidification, then forming a conductor wire and tin-plating to form a hybrid conductor.

[0040] Composite optical fibers are formed by attaching a composite protective sleeve to the outer wall of the distributed optical fiber.

[0041] A cable monitoring composite structure is formed by spirally twisting multiple hybrid conductors and two composite optical fibers to simultaneously form a cable core layer and a monitoring function layer.

[0042] A high-elasticity EPDM rubber capillary is made into a cylindrical ring structure. Micropore channels are processed on the surface of the EPDM rubber capillary. The capillary is then fitted onto the outer surface of the cable core layer and spaced apart. A suitable amount of silicone oil is then pressure-filled into the micropore channels one by one to form a ring-shaped stress dispersion structure.

[0043] The permalloy strip is wrapped around the outside of the intertwined cable monitoring composite structure using a longitudinal wrapping process and then fixed. Finally, a tin-plated copper braided mesh is placed over the outside of the permalloy strip.

[0044] An insulating protective layer is extruded and wrapped around the outside of the electromagnetic shielding layer.

[0045] The outer protective layer is formed by extrusion, and glass fiber reinforcing particles are embedded during the extrusion process.

[0046] A polyethylene film is wrapped around the outer protective layer, and then a fiber woven mesh is wrapped around the outside to form a rodent- and ant-proof composite layer.

[0047] Based on any of the above technical solutions, a further optimization is made: the center of the cable monitoring composite structure is a hollow cavity structure.

[0048] Based on any of the above technical solutions, the following further optimization is made: In the step of adding cadmium sulfide or lead selenide nanoparticles after melting the aluminum matrix raw material, the melting temperature is controlled at 720±10℃, and the melt temperature is monitored in real time by an infrared thermometer; the nanoparticle addition rate is controlled at 0.1-0.3g / s, and a vibrating feeder is used for uniform feeding; the high-speed stirring stage is carried out in two stages: first, stirring at 1800r / min for 5 minutes, and then reducing to 1500r / min until the nanoparticles are completely added, to avoid violent turbulence causing melt splashing.

[0049] Based on any of the above technical solutions, a further optimization is made as follows: In the step of attaching the composite protective sleeve to the outer wall of the distributed optical fiber, the polyurethane elastomer layer is coated using a thermal spraying process, with the coating thickness controlled at 0.1-0.15 mm, the curing temperature at 80-100℃, and the curing time at 10-15 minutes; the silicone rubber layer is simultaneously coated using an extruder, with the extrusion temperature set at 150-180℃, and the matching error between the traction speed and the optical fiber laying speed ≤ ±0.5%;

[0050] The hydrophobic layer of polyvinylidene fluoride is applied using a solution coating method. The coating contains 5-8% by mass of nano-silica particles to enhance the hydrophobic properties.

[0051] Based on any of the above technical solutions, the following further optimization is made: In the step of spirally stranding the multiple hybrid conductors and two composite optical fibers, the stranding pitch is controlled to be 8-12 times the outer diameter of the conductor, a planetary stranding device is used, and the stranding direction is right-handed; a tension of 0.05-0.1 MPa is applied during the stranding process, and the tension is monitored in real time by a tension sensor to ensure that the stranded structure is tight and not loose; an aramid fiber reinforcing core is pre-placed in the hollow cavity structure to improve the overall tensile strength of the cable.

[0052] Based on any of the above technical solutions, the following optimization is made: In the step of pressure filling silicone oil into the microporous channels, the silicone oil viscosity is selected as 50-100 cSt (25℃), the filling pressure is 0.2-0.3MPa, and a gear pump is used for quantitative delivery; during the filling process, the temperature of the EPDM rubber capillary is maintained at 40-50℃ by a constant temperature heating jacket to improve the fluidity of the silicone oil; after filling, the capillary is left to stand for 30 minutes, and residual air in the microporous channels is removed by vacuum negative pressure to ensure a filling rate of ≥95%.

[0053] Based on any of the above technical solutions, the following further optimization is made: In the step of wrapping the polyethylene film around the outer protective layer, the thickness of the polyethylene film is controlled to be 0.08-0.12mm, the winding tension is 5-8N, the overlap rate is 30-40%, and wrinkle-free is ensured; the fiber woven mesh is made of aramid fiber and glass fiber mixed weaving (mixing ratio 7:3), and the weaving density is ≥1200 mesh / square inch.

[0054] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0055] 1. The monitoring functional layer of the present invention is tightly wound in a spiral shape on the outer surface of the cable core layer. This design ensures that the optical fiber and the cable core layer are in close contact, and that the temperature change and mechanical deformation of the cable core layer can be quickly transmitted to the optical fiber, thus solving the monitoring lag problem caused by the gap in the traditional loose tube structure.

[0056] 2. In the design of the double-layer structure of the electromagnetic shielding layer of this invention, consisting of a permalloy strip and a tin-plated copper braided mesh, the initial permeability of the permalloy strip generates a magnetic shunt effect in a 50Hz power frequency magnetic field. Magnetic lines of force preferentially close through the high-permeability shielding layer, reducing the internal magnetic field strength and improving shielding effectiveness.

[0057] 3. The present invention provides an annular stress dispersion structure consisting of EPDM rubber tubes and silicone oil filling at intervals outside the cable core layer. The surface of the tubes is processed with microporous channels, and combined with the pre-placed aramid fiber reinforcing core in the center, a solid-liquid coupling and rigid support structure is formed, which improves the tensile strength and bending resistance of the cable.

[0058] 4. The rodent- and ant-proof composite layer of the present invention uses a polyethylene film containing repellent particles and an aramid / glass fiber hybrid mesh to form a dual protection of chemical repellency and physical barrier, inhibiting biological adhesion and corrosion, and extending the service life of the cable.

[0059] 5. The present invention features a hollow cavity at the center of the cable monitoring composite structure, which is formed using a removable core rod process. An aramid fiber reinforcing core or a spare optical fiber can be pre-placed inside the cavity. Combined with a spiral stranding process, this ensures a tight and non-loose structure. Attached Figure Description

[0060] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the accompanying drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. In all the drawings, similar elements or components are generally identified by similar reference numerals. In the drawings, the elements or components are not necessarily drawn to scale.

[0061] Figure 1 This is a schematic diagram of the cable cross-section structure of the present invention.

[0062] Figure 2 This is a schematic diagram of the spiral winding structure of the cable core layer and the monitoring functional layer of the present invention.

[0063] In the diagram, 1 is the cable core layer; 101 is the hybrid conductor; 2 is the monitoring functional layer; 3 is the high-elasticity EPDM rubber capillary tube; 301 is the microporous channel; 4 is the optical fiber; 5 is the composite protective sheath; 501 is the polyurethane elastomer layer; 502 is the silicone rubber layer; 503 is the polyvinylidene fluoride hydrophobic layer; 6 is the permalloy tape; 7 is the tin-plated copper braided mesh; 8 is the insulating protective layer; 9 is the outer sheath; 10 is the polyethylene film; 11 is the fiber braided mesh; and 12 is the aramid fiber reinforcing core. Detailed Implementation

[0064] The embodiments of the technical solution of the present invention will now be described in detail with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore merely examples and should not be used to limit the scope of protection of the present invention. The specific structure of the present invention is as follows: Figures 1-2 As shown in the image.

[0065] Example 1: An anti-interference fiber optic monitoring cross-linked cable, the cable comprising, from the inside out, a cable core layer, a monitoring functional layer, an electromagnetic shielding layer, an insulation protection layer, and an outer sheath; the cable core layer comprises multiple hybrid conductors formed by spiral stranding; the monitoring functional layer is tightly wound spirally around the outer surface of the cable core layer; the electromagnetic shielding layer is located between the monitoring functional layer and the insulation protection layer; the electromagnetic shielding layer has a multi-layer structure, with an inner layer of permalloy tape and an outer layer of tin-plated copper braided mesh; and several rodent-proof composite layers are spaced apart along the length of the outer wall of the outer sheath.

[0066] This invention achieves functional modularity through a layered structural design. The spiral twisting and winding process forms a compact physical support. The multi-layer electromagnetic shield absorbs external interference through the high permeability of the permalloy strip and the electromagnetic reflection of the tin-plated copper braided mesh. The rodent-proof composite layer prevents biological infestation through a combination of physical barrier and chemical repellency.

[0067] The cable core layer uses a hybrid conductor spiral stranded aluminum matrix as the conductive body, and cadmium sulfide / lead selenide nanoparticles form local conductive channels through quantum confinement effect, reducing the probability of electron scattering and keeping the conductivity of the hybrid conductor stable.

[0068] In addition, the spiral stranding process (pitch is 8-12 times the outer diameter of the conductor) forms a spiral angle by right-hand stranding, which causes each mixed conductor to generate radial constraint force under the action of axial electric field, suppressing the radial expansion of a single conductor caused by the skin effect of current.

[0069] Applying a tension of 0.05-0.1 MPa during stranding generates pre-tight friction between the mixed conductors, improving the overall tensile strength of the cable core.

[0070] When the cable is overloaded and the temperature rises above 150°C, microcracks are generated at the interface between the cadmium sulfide nanoparticles and the aluminum matrix due to the difference in the coefficient of thermal expansion, forming air gaps. The reduction in the equivalent dielectric constant causes local electric field distortion, thereby triggering the fiber optic stress monitoring signal of the monitoring functional layer to achieve overload early warning.

[0071] During the stranding process, the tin plating layer on the mixed conductor surface undergoes tiny tin crystal transfer due to friction, forming a nanoscale lubricating film in the conductor gaps. This reduces the coefficient of friction of the cable core layer during the stretching process, thereby reducing the traction force required during laying.

[0072] The design of the distributed optical fiber spiral winding structure of the monitoring functional layer can utilize the polyurethane elastomer layer of the composite protective sleeve as a stress transfer medium to convert the mechanical deformation (such as tension and bending) of the cable core layer into the axial strain of the optical fiber. The silicone rubber layer isolates the electrochemical corrosion of the optical fiber coating by the high voltage electric field of the cable core layer.

[0073] In the design of the double-layer structure of permalloy strip and tin-plated copper braided mesh for electromagnetic shielding, the initial permeability of the permalloy strip generates a magnetic shunt effect in a 50Hz power frequency magnetic field. Magnetic lines of force preferentially close through the high-permeability shielding layer, reducing the internal magnetic field strength and improving shielding effectiveness. The tin-plated copper braided mesh (diameter 0.15-0.2mm, braiding density ≥85%) generates eddy currents through electromagnetic induction. The eddy current magnetic field is superimposed in opposite directions with the external interference magnetic field, further enhancing the overall shielding effectiveness.

[0074] When an electric arc discharge occurs inside the cable, the magnetic saturation properties of the permalloy strip can suppress the diffusion of the arc plasma, reduce the arc energy density, shorten the arc duration, and reduce the risk of insulation layer ablation.

[0075] In addition, the glass fiber embedded in the outer sheath forms a radial heat conduction channel, which reduces the thermal resistance of the cable body and increases the current carrying capacity when operating at full load.

[0076] Based on any of the above technical solutions, a further optimization is made to the following: the hybrid conductor includes an aluminum matrix, in which cadmium sulfide or lead selenide particles with a particle size in the range of 5-10 nanometers are dispersed.

[0077] The conductor performance is improved by the synergistic effect of cadmium sulfide or lead selenide nanoparticles with the aluminum matrix. From the perspective of material interface effect, 5-10 nanometer cadmium sulfide or lead selenide particles have a large specific surface area and form a large number of nanoscale interfaces with the matrix metal. These interfaces act as obstacles to dislocation movement.

[0078] According to the Hall-Page relation, the yield strength of a conductor increases with increasing interfacial density, effectively resisting the mechanical stress during cable stranding and laying.

[0079] Specifically, cadmium sulfide or lead selenide particles with a diameter of 5-10 nanometers can have a specific surface area of ​​100-200 m² / g (particle diameter is inversely proportional to specific surface area), which is 10-30 times higher than that of traditional micron-sized particles (such as 1 μm particles, with a specific surface area of ​​about 6 m² / g). The high specific surface area enables the formation of numerous nanoscale interfaces per unit volume of aluminum matrix, which act as physical barriers to dislocation movement.

[0080] The nanoparticles form a Schottky barrier at the interface with the aluminum matrix, which promotes the directional migration of electrons at the interface, reduces contact resistance, and ensures conductivity.

[0081] Increased interface density leads to an effective grain size refinement to the nanometer scale, which improves the yield strength of the hybrid conductor compared to the pure aluminum matrix.

[0082] Based on any of the above technical solutions, a further optimization is made to the specific preparation method of the hybrid conductor as follows:

[0083] First, heat the aluminum matrix raw material to a molten state, controlling the temperature at 700-750℃, in order to reduce its viscosity and facilitate the dispersion of nanoparticles.

[0084] Subsequently, cadmium sulfide or lead selenide nanoparticles with a particle size of 5-10 nanometers are slowly added to the molten aluminum matrix at a ratio of 0.5-1.5% by weight.

[0085] During the addition process, maintain high-speed stirring, with the stirring speed set at 1500-2000 r / min, so that the nanoparticles are initially dispersed in the aluminum melt.

[0086] After all the nanoparticles have been added, ultrasonic dispersion is initiated. The ultrasonic frequency is set to 20-40 kHz, the power to 500-1000 W, and the ultrasonic time to 15-30 minutes. (The cavitation effect generated during ultrasonic dispersion can effectively break the agglomeration of nanoparticles, allowing cadmium sulfide or lead selenide nanoparticles to be uniformly distributed in a monodisperse state within the aluminum matrix. Simultaneously, the mechanical vibration of ultrasound can promote the interdiffusion between nanoparticles and aluminum matrix atoms, enhancing the interfacial bonding force between the two.)

[0087] After high-speed stirring and ultrasonic dispersion, the resulting mixture is injected into a mold for rapid cooling. The cooling rate is controlled at 50-100℃ / s to rapidly solidify the aluminum matrix, fix the uniform dispersion of nanoparticles, and prevent nanoparticles from agglomerating or segregating.

[0088] The cooled mixture is processed into conductor wires using a continuous extrusion process;

[0089] The conductor wire is tin-plated, with the tin plating layer thickness controlled between 0.01 and 0.03 mm, to improve the conductor's oxidation resistance and electrical connection performance.

[0090] A tin layer is formed on the surface of the hybrid conductor, which can form eutectic solder during electrical connection and reduce contact resistance.

[0091] Based on any of the above technical solutions, a further optimization is made as follows: the monitoring functional layer includes a distributed optical fiber, a composite protective sleeve is sleeved on the outer wall of the distributed optical fiber, and the monitoring functional layer is tightly wrapped around the outer surface of the cable core layer.

[0092] The monitoring functional layer is tightly wound in a spiral shape on the outer surface of the cable core. This design ensures that the optical fiber and the cable core are in close contact, and that temperature changes and mechanical deformations of the cable core can be quickly transmitted to the optical fiber, solving the monitoring lag problem caused by gaps in traditional loose tube structures.

[0093] The splicing and winding processes of the composite protective sleeve can be completed simultaneously on the cable stranding production line without the need for additional complex equipment, resulting in high production efficiency and good compatibility with subsequent electromagnetic shielding and insulation protection layer coating processes.

[0094] The tight winding process (winding tension 5-8N, overlap rate 30-40%) minimizes the interface gap between the monitoring functional layer and the cable core layer, thereby improving the strain transfer coefficient through contact conduction. When the cable core layer undergoes mechanical deformation due to bending or stretching, the distributed optical fibers synchronously sense the deformation, avoiding strain lag caused by gaps in traditional loose structures and ensuring the accuracy of real-time monitoring.

[0095] The tightly wound spiral angle (usually 20°-40°) intersects with the longitudinal wrapping direction (axial direction) of the permalloy tape of the electromagnetic shielding layer. This suppresses the interference of the annular magnetic field generated by the alternating current in the core layer on the magneto-optical effect of the optical fiber, reduces the fluctuation of the polarization degree of the optical signal, and ensures the signal-to-noise ratio of the monitoring signal.

[0096] Based on any of the above technical solutions, a further optimization is made: the composite protective sleeve includes, from the inside out, a polyurethane elastomer layer, a silicone rubber layer, and a polyvinylidene fluoride hydrophobic layer.

[0097] The polyurethane elastomer layer (thickness 0.1-0.15mm) provides mechanical cushioning and primary protection, the silicone rubber layer (thickness 0.1-0.2mm) provides insulation and environmental sealing, and the polyvinylidene fluoride hydrophobic layer (thickness 0.05-0.1mm) provides hydrophobic protection and surface strengthening.

[0098] Based on any of the above technical solutions, the following further optimization is made: the electromagnetic shielding layer includes an inner permalloy strip and an outer tin-plated copper braided mesh. The permalloy strip is wrapped around the monitoring functional layer by a longitudinal wrapping process, and the overlap width between adjacent layers is ≥10mm. The overlap is fixed by ultrasonic welding or conductive adhesive. The tin-plated copper braided mesh covers the outer side of the permalloy strip at a braiding angle of 45°-60° with a braiding density of ≥85%.

[0099] Permalloy tape can produce a magnetic shunt effect against low-frequency interference such as 50Hz power frequency magnetic fields. When an external low-frequency magnetic field acts on the cable, the magnetic lines of force will preferentially pass through the high-permeability permalloy tape to form a closed loop, rather than passing through the inside of the cable, thereby significantly reducing the magnetic field strength inside the cable.

[0100] The overlap width of two adjacent layers of permalloy tape is ≥10mm and they are bonded by ultrasonic welding or conductive adhesive to ensure the continuity of the magnetic path and avoid the decrease in magnetic permeability due to air gaps, which can reduce the intensity of low-frequency magnetic fields inside the cable.

[0101] Tin-plated copper braided mesh has high electrical conductivity and can generate eddy currents through electromagnetic induction for high-frequency electromagnetic fields above 100MHz. The reverse magnetic field generated by the eddy currents superimposes and cancels out the external interference magnetic field, thus achieving electromagnetic shielding.

[0102] Based on any of the above technical solutions, a further optimization is made of cross-linked polyethylene material for the insulating protective layer and polyvinyl chloride or low-smoke halogen-free flame-retardant polyolefin material for the outer protective layer.

[0103] Based on any of the above technical solutions, a further optimization is made of: annular stress dispersion structures are provided at intervals along the length of the cable core layer. The annular stress dispersion structures are made of highly elastic EPDM rubber tubes, which are tightly fitted onto the outer surface of the cable core layer to form a cylindrical annular stress dispersion structure.

[0104] Taking bending conditions as an example, the circumferential tensile strain of the EPDM rubber capillary can absorb the bending stress of the cable core layer, thereby reducing the maximum stress borne by the hybrid conductor.

[0105] The ring-shaped stress dispersion structure can absorb the stress generated by the cable under bending and tensile conditions, protect the hybrid conductor from damage, and improve the reliability and service life of the cable core layer.

[0106] The surface of the EPDM rubber capillary has several micropores that connect the inside and outside of it, and the EPDM rubber capillary is pre-filled with an appropriate amount of silicone oil.

[0107] Microporous channel structure can further improve the elasticity and buffering performance of the structure. When the cable core layer is subjected to external force and bending deformation, silicone oil has good lubrication and buffering performance. Moreover, silicone oil can play a better buffering and stress dispersion role after seeping out through microporous channels.

[0108] In addition, the microporous channels (0.1-0.3 mm in diameter) on the surface of the capillary tube form a solid-liquid coupling with the silicone oil (viscosity 50-100 cSt) inside: when the cable is subjected to impact load (such as instantaneous tensile force ≥5000 N during laying), the silicone oil seeps out through the microporous channels and forms a lubricating film at the interface between the cable core layer and the EPDM rubber capillary tube, reducing the coefficient of friction and thus reducing the stress concentration factor; in addition, the viscous damping effect of the silicone oil can dissipate high-frequency vibration energy, improve the vibration attenuation rate, and avoid fatigue fracture of the hybrid conductor caused by resonance.

[0109] Based on any of the above technical solutions, a further optimization is made as follows: the anti-rodent and anti-ant composite layer includes a polyethylene film containing repellent particles inside, the polyethylene film is wrapped around the outer wall of the outer protective layer, and a fiber woven mesh is wrapped around the outside of the polyethylene film; the polyethylene film is prepared by blow molding process from high-density polyethylene, repellent particles, and antioxidants.

[0110] The method for preparing polyethylene film is as follows:

[0111] 1. Raw material preparation:

[0112] Materials: High-density polyethylene, repellent particles (particle size ≤ 50 μm), antioxidant.

[0113] Mass ratio: 85-92% high-density polyethylene, 5-10% repellent particles, and 1-3% antioxidant.

[0114] 2. Blending and granulation:

[0115] Premix: Put the raw materials into a high-speed mixer and mix for 10-15 minutes at 800-1200 r / min.

[0116] Extrusion: Twin-screw extruder temperature 160-210℃, screw speed 150-200r / min, water-cooled pelletizing (particle size 2-4mm).

[0117] 3. Blow molding: Single screw blown film machine (screw diameter 60-90mm), die temperature 180-200℃.

[0118] Steps: After plasticizing the granules, they are extruded into tube blanks with a blow-up ratio of 2-3:1 and a traction speed of 5-10m / min; cooled and shaped, with a winding tension of 10-15N.

[0119] The rodent- and ant-repellent composite layer employs a dual-layer approach, relying on repellent particles (such as capsaicin derivatives and copper powder) added to the polyethylene film to create a concentration gradient on the film surface through molecular diffusion. When rodents or ants come into contact with the film, the repellent binds to olfactory and tactile receptors, triggering an avoidance response.

[0120] The outer layer of woven fiber mesh (such as a blend of aramid and glass fibers, with a weaving density ≥1200 mesh / square inch) forms a dense physical barrier. Its mesh size is ≤0.1mm, which can block the bites of rodents and ants (rodent incisor hardness ≤200HV). The woven fiber mesh has a tensile strength ≥500MPa and an elongation at break ≤5%, capable of withstanding the biting force of rodents and ants (rodent bite force ≤100N) without breaking, effectively preventing biological and physical attacks.

[0121] The present invention also provides a method for molding and manufacturing an anti-interference fiber optic monitoring cross-linked cable, comprising the following steps: melting aluminum matrix raw material and adding cadmium sulfide or lead selenide nanoparticles, stirring, ultrasonically dispersing and cooling solidification, then forming a conductor wire and tin-plating to form a hybrid conductor.

[0122] Composite optical fibers are formed by attaching a composite protective sleeve to the outer wall of the distributed optical fiber.

[0123] A cable monitoring composite structure is formed by spirally twisting multiple hybrid conductors and two composite optical fibers to simultaneously form a cable core layer and a monitoring function layer.

[0124] A high-elasticity EPDM rubber capillary is made into a cylindrical ring structure. Micropore channels are processed on the surface of the EPDM rubber capillary. The capillary is then fitted onto the outer surface of the cable core layer and spaced apart. A suitable amount of silicone oil is then pressure-filled into the micropore channels one by one to form a ring-shaped stress dispersion structure.

[0125] The permalloy strip is wrapped around the outside of the intertwined cable monitoring composite structure using a longitudinal wrapping process and then fixed. Finally, a tin-plated copper braided mesh is placed over the outside of the permalloy strip.

[0126] An insulating protective layer is extruded and wrapped around the outside of the electromagnetic shielding layer.

[0127] The outer protective layer is formed by extrusion, and glass fiber reinforcing particles are embedded during the extrusion process.

[0128] A polyethylene film is wrapped around the outer protective layer, and then a fiber woven mesh is wrapped around the outside to form a rodent- and ant-proof composite layer.

[0129] Based on any of the above technical solutions, the following further optimization is made: the center of the cable monitoring composite structure is a hollow cavity structure; the hollow cavity structure is pre-installed with an aramid fiber reinforcing core.

[0130] The aramid fiber reinforcing core, through its twisted structure, forms a core-coordinated, periphery-coordinated force-bearing system with the hybrid conductor and composite optical fiber. When the cable is stretched by external force, the aramid fiber reinforcing core bears a large amount of tensile force, while the hybrid conductor only bears the remaining load, thus avoiding the reduction in cross-sectional area and mechanical damage to the hybrid conductor due to excessive stretching.

[0131] Example 2: Compared with Example 1, this example also includes the following technical features:

[0132] Based on any of the above technical solutions, the following further optimization is made: In the step of adding cadmium sulfide or lead selenide nanoparticles after melting the aluminum matrix raw material, the melting temperature is controlled at 720±10℃, and the melt temperature is monitored in real time by an infrared thermometer; the nanoparticle addition rate is controlled at 0.1-0.3g / s, and a vibrating feeder is used for uniform feeding; the high-speed stirring stage is carried out in two stages: first, stirring at 1800r / min for 5 minutes, and then reducing to 1500r / min until the nanoparticles are completely added, to avoid violent turbulence causing melt splashing.

[0133] Aluminum has a melting point of approximately 660℃. Setting the melting temperature at 720±10℃, which is higher than aluminum's melting point, ensures that the aluminum matrix material melts completely to form a homogeneous melt, providing a good mixing environment for the subsequent addition of nanoparticles. At the same time, the temperature is not too high, preventing excessive oxidation of the aluminum melt and reducing the degradation of the aluminum matrix's properties. It also prevents the decomposition or structural damage of cadmium sulfide and lead selenide nanoparticles at high temperatures, ensuring that the inherent properties of the nanoparticles remain unaffected. Real-time monitoring with an infrared thermometer allows for precise temperature control, ensuring that the entire melting process remains stable within the set range.

[0134] Meanwhile, using a vibrating feeder to uniformly feed cadmium sulfide or lead selenide nanoparticles at a speed of 0.1-0.3 g / s allows them to gradually and stably enter the molten aluminum. If the feeding speed is too fast, the nanoparticles tend to aggregate locally, making it difficult to disperse evenly and resulting in uneven performance of the subsequently produced mixed conductor; while if the speed is too slow, it will prolong processing time and reduce production efficiency. The vibration of the vibrating feeder further ensures the uniformity of nanoparticle feeding, laying the foundation for subsequent dispersion steps.

[0135] In addition, in the initial stage, the nanoparticles are stirred at a high speed of 1800 r / min for 5 minutes to quickly break up the initial agglomeration state of the nanoparticles by using strong shear force, so that the nanoparticles are initially dispersed into the aluminum melt and a preliminary mixed system is formed.

[0136] When nanoparticles are continuously added, reducing the stirring speed to 1500 r / min can maintain a certain dispersion capacity while avoiding severe turbulence caused by excessively high speeds. Severe turbulence may cause aluminum molten material to splash, resulting in material waste and safety hazards. It may also cause nanoparticles to re-agglomerate under the impact of turbulence, affecting the dispersion effect. Staged stirring can ensure uniform dispersion of nanoparticles while taking into account both production safety and efficiency.

[0137] Based on any of the above technical solutions, a further optimization is made as follows: In the step of attaching the composite protective sleeve to the outer wall of the distributed optical fiber, the polyurethane elastomer layer is coated using a thermal spraying process, with the coating thickness controlled at 0.1-0.15 mm, the curing temperature at 80-100℃, and the curing time at 10-15 minutes; the silicone rubber layer is simultaneously coated using an extruder, with the extrusion temperature set at 150-180℃, and the matching error between the traction speed and the optical fiber laying speed ≤ ±0.5%;

[0138] The hydrophobic layer of polyvinylidene fluoride is applied using a solution coating method. The coating contains 5-8% by mass of nano-silica particles to enhance the hydrophobic properties.

[0139] Polyurethane particles (50-100μm in diameter) are melted under thermal spraying conditions at 80-100℃ and undergo molecular chain diffusion cross-linking with the UV-cured acrylate coating on the surface of the optical fiber to form an elastic buffer layer with a thickness of 0.1-0.15mm.

[0140] It should be noted that the surface of the optical fiber is pre-treated with plasma (discharge power 50-100W, treatment time 30s) to improve its roughness, so that the molten polyurethane can penetrate into the micro-groove and form an anchoring effect.

[0141] Curing temperature 80-100℃: This prevents the fiber coating (glass transition temperature 60℃) from softening due to overheating, while ensuring full cross-linking of the polyurethane.

[0142] Based on any of the above technical solutions, the following further optimization is made: In the step of spirally stranding the multiple hybrid conductors and two composite optical fibers, the stranding pitch is controlled to be 8-12 times the outer diameter of the conductor, a planetary stranding device is used, and the stranding direction is right-handed; a tension of 0.05-0.1 MPa is applied during the stranding process, and the tension is monitored in real time by a tension sensor to ensure that the stranded structure is tight and not loose; an aramid fiber reinforcing core is pre-placed in the hollow cavity structure to improve the overall tensile strength of the cable.

[0143] Tension of 0.05-0.1MPa is applied by a magnetic powder brake, and the tension sensor (accuracy ±0.5% FS) provides real-time feedback and adjustment.

[0144] Based on any of the above technical solutions, the following optimization is made: In the step of pressure filling silicone oil into the microporous channels, the silicone oil viscosity is selected as 50-100 cSt (25℃), the filling pressure is 0.2-0.3MPa, and a gear pump is used for quantitative delivery; during the filling process, the temperature of the EPDM rubber capillary is maintained at 40-50℃ by a constant temperature heating jacket to improve the fluidity of the silicone oil; after filling, the capillary is left to stand for 30 minutes, and residual air in the microporous channels is removed by vacuum negative pressure to ensure a filling rate of ≥95%.

[0145] Based on any of the above technical solutions, the following further optimization is made: In the step of wrapping the polyethylene film around the outer protective layer, the thickness of the polyethylene film is controlled to be 0.08-0.12mm, the winding tension is 5-8N, the overlap rate is 30-40%, and wrinkle-free is ensured; the fiber woven mesh is made of aramid fiber and glass fiber mixed weaving (mixing ratio 7:3), and the weaving density is ≥1200 mesh / square inch.

[0146] Fiber woven mesh utilizes a blend of aramid and glass fibers to form a specific high-strength, high-toughness, low-cost protective structure. Furthermore, existing weaving equipment (such as a 16-spindle high-speed weaving machine) can achieve a weaving density of ≥1200 mesh by changing the molds, and the film wrapping machine has a tension control accuracy of ±0.5N, making it suitable for large-scale production and demonstrating good feasibility.

[0147] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention. For those skilled in the art, any alternative improvements or transformations made to the implementation of the present invention fall within the protection scope of the present invention.

[0148] Any aspects of this invention not described in detail are well-known to those skilled in the art.

Claims

1. An anti-interference fiber optic monitoring cross-linked cable, characterized in that: The cable comprises, from the inside out, a cable core layer, a monitoring function layer, an electromagnetic shielding layer, an insulation protection layer, and an outer sheath. The cable core layer consists of multiple hybrid conductors, which are formed by spiral stranding. The monitoring function layer is tightly wound in a spiral shape around the outer surface of the cable core layer. The electromagnetic shielding layer is located between the monitoring function layer and the insulation protection layer. The electromagnetic shielding layer has a multi-layer structure, with an inner layer of permalloy tape and an outer layer of tin-plated copper braided mesh. Several rodent-proof composite layers are spaced along the length of the outer wall of the outer sheath.

2. The anti-interference fiber optic monitoring cross-linked cable according to claim 1, characterized in that: The hybrid conductor comprises an aluminum matrix in which cadmium sulfide or lead selenide particles with a particle size in the range of 5-10 nanometers are dispersed.

3. The anti-interference fiber optic monitoring cross-linked cable according to claim 2, characterized in that: The specific preparation method of the hybrid conductor is as follows: First, heat the aluminum matrix raw material to a molten state, controlling the temperature at 700-750℃; Subsequently, cadmium sulfide or lead selenide nanoparticles with a particle size of 5-10 nanometers were slowly added to the molten aluminum matrix at a ratio of 0.5-1.5% by weight. During the addition process, maintain high-speed stirring to initially disperse the nanoparticles in the aluminum melt; After all the nanoparticles have been added, start ultrasonic dispersion and control the ultrasonic time to 15-30 minutes. After high-speed stirring and ultrasonic dispersion, the resulting mixture is injected into a mold for rapid cooling. The cooling rate is controlled at 50-100℃ / s to rapidly solidify the aluminum matrix, fix the uniform dispersion of nanoparticles, and prevent nanoparticles from agglomerating or segregating. The cooled mixture is processed into conductor wires using a continuous extrusion process; The conductor wire is tin-plated, and the thickness of the tin plating layer is controlled between 0.01 and 0.03 mm.

4. The anti-interference fiber optic monitoring cross-linked cable according to claim 3, characterized in that: The monitoring functional layer includes distributed optical fibers, with a composite protective sleeve fitted onto the outer wall of the distributed optical fibers, and the monitoring functional layer is tightly wrapped around the outer surface of the cable core layer.

5. The anti-interference fiber optic monitoring cross-linked cable according to claim 4, characterized in that: The electromagnetic shielding layer includes an inner permalloy strip and an outer tin-plated copper braided mesh. The permalloy strip is wrapped around the monitoring functional layer by a longitudinal wrapping process, and the overlap width between adjacent layers is ≥10mm. The overlap is fixed by ultrasonic welding or conductive adhesive. The tin-plated copper braided mesh covers the outer side of the permalloy strip at a weaving angle of 45°-60° with a weaving density of ≥85%.

6. The anti-interference fiber optic monitoring cross-linked cable according to claim 5, characterized in that: The insulating protective layer is made of cross-linked polyethylene material; the outer protective layer is made of polyvinyl chloride or low-smoke halogen-free flame-retardant polyolefin material.

7. The anti-interference fiber optic monitoring cross-linked cable according to claim 6, characterized in that: A ring-shaped stress dispersion structure is provided at intervals along the length of the cable core layer. The ring-shaped stress dispersion structure is made of highly elastic EPDM rubber tubes. The EPDM rubber tubes are tightly fitted on the outer surface of the cable core layer to form a cylindrical ring-shaped stress dispersion structure. The surface of the EPDM rubber capillary has several micropores that connect the inside and outside of it, and the EPDM rubber capillary is pre-filled with an appropriate amount of silicone oil.

8. The anti-interference fiber optic monitoring cross-linked cable according to claim 7, characterized in that: The rodent- and ant-proof composite layer includes a polyethylene film containing repellent particles inside, the polyethylene film being wrapped around the outer wall of the outer protective layer, and a fiber woven mesh being wrapped around the outside of the polyethylene film; the polyethylene film is prepared by blow molding process from high-density polyethylene, repellent particles, and antioxidants.

9. A method for molding and manufacturing an anti-interference fiber optic monitoring cross-linked cable, characterized in that, Includes the following steps: After melting aluminum matrix raw materials, cadmium sulfide or lead selenide nanoparticles are added, stirred, ultrasonically dispersed, cooled and solidified, and then made into conductor wires and tin-plated to form a hybrid conductor. A composite optical fiber is formed by attaching a composite protective sleeve to the outer wall of the distributed optical fiber. A cable monitoring composite structure is formed by spirally twisting multiple hybrid conductors and two composite optical fibers and simultaneously forming a cable core layer and a monitoring function layer. A cylindrical ring structure is made of a high-elasticity EPDM rubber capillary. Micropore channels are processed on the surface of the EPDM rubber capillary. The capillary is then fitted onto the outer surface of the cable core layer and spaced apart. A suitable amount of silicone oil is then pressure-filled into the micropore channels one by one to form a ring-shaped stress dispersion structure. The permalloy strip is wrapped around the outside of the intertwined cable monitoring composite structure using a longitudinal wrapping process and then fixed. A tin-plated copper braided mesh is then covered on the outside of the permalloy strip. The insulating protective layer is extruded and coated on the outside of the electromagnetic shielding layer; The outer protective layer is formed by extrusion, and glass fiber reinforcing particles are embedded during the extrusion process; On the surface of the outer protective layer that has just been extruded and is in a soft state; A polyethylene film is wrapped around the outer protective layer, and then a fiber woven mesh is wrapped around the outside to form a rodent- and ant-proof composite layer.

10. The molding and manufacturing method according to claim 9, characterized in that: in, The center of the cable monitoring composite structure is a hollow cavity.

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