A high-strength overhead insulated cable

Abstract

This invention provides a high-strength overhead insulated cable, comprising, from the inside out, a high-strength load-bearing core, a conductor, a filler layer, a first buffer layer, a metal thermally conductive layer, a second buffer layer, and an insulating sheath. The first buffer layer features cavities and temperature-controlled bridging ribs, achieving dynamic thermal management through low-load air insulation to mitigate internal temperature fluctuations and high-load temperature-sensitive expansion to establish a solid thermal conduction path. The second buffer layer alternately features static anchoring zones and stress relief cavities, perfectly balancing interlayer anti-slip and thermal expansion absorption. Integrated phase-change heat-absorbing material within the second buffer layer smooths transient thermal loads. By using semi-conductive materials from the filler layer to the second buffer layer, this invention ensures all internal buffer cavities are within a closed equipotential Faraday cage, physically eliminating the risk of partial discharge in high-voltage electric fields. This achieves a perfect synergy between mechanical relief, dynamic thermal management, and high-voltage insulation shielding, significantly improving the cable's safe current carrying capacity and service life.

Description

Technical Field

[0001] This invention relates to the field of cable technology, and more particularly to a high-strength overhead insulated cable. Background Technology

[0002] With the rapid development of modern urban power grids, ultra-high voltage power transmission and distribution projects, and long-span power transmission projects in remote areas, overhead insulated cables have been widely used due to their advantages such as low laying cost, strong environmental adaptability, and high power supply reliability. In recent years, the integration of new energy sources into modern power grids has brought about frequent "peak-valley alternation" phenomena, coupled with frequent occurrences of short-term overload operation, which has subjected overhead cables to unprecedented thermodynamic and mechanical challenges.

[0003] Under long-span and heavy-load conditions, the conductors inside overhead cables experience significant radial thermal expansion and compressive stress due to frequent and drastic temperature changes. Current technology typically incorporates a highly compressible, soft buffer layer inside the cable to absorb thermal expansion. However, this flexible structure is highly susceptible to interlayer slippage and wrinkling failure when the cable is subjected to strong wind vibrations, icing loads, or significant mechanical bending. Conversely, using a high-strength, rigid buffer structure to prevent slippage results in a loss of thermal expansion absorption capacity, leading to fatigue cracking of the outer insulation layer under long-term alternating thermal expansion and contraction stress.

[0004] Even more challenging is that traditional overhead cables, due to the significant differences in the coefficients of thermal expansion of their various materials (such as metallic conductors and polymer insulation layers), are prone to generating enormous interlayer shear stress and interfacial tensile forces when subjected to high-frequency thermal cycles of "rapid expansion under full load - rapid cooling and contraction under sudden load drop." While the traditional static, tightly bonded internal structure is beneficial for initial heat conduction, it often leads to interlayer micro-delamination during the cooling and contraction phase due to insufficient release of internal stress, resulting in partial discharge. Furthermore, traditional cables with pre-existing physical air gaps significantly sacrifice thermal conductivity, limiting the cable's ultimate current carrying capacity. In addition, when encountering transient short circuits or short-term overload conditions, the traditional static heat-conducting structure cannot dissipate the surge in sudden heat load in a very short time, easily leading to localized instantaneous overheating, thereby accelerating the aging of the insulation material or even causing thermal breakdown.

[0005] Given the aforementioned challenges, the key technical bottleneck restricting the development of high-capacity overhead insulated cables lies in how to ensure the shear stability between cable layers and provide sufficient non-destructive deformation "breathing" margin for thermal expansion and contraction under the dual harsh conditions of extreme climate and high-frequency thermal cycling, while also taking into account the dynamic thermo-mechanical collaborative management requirements of "normal flexible yielding to prevent peeling and high-load adaptive rapid heat dissipation."

[0006] Therefore, it is necessary to invent a high-strength overhead insulated cable to solve the above problems. Summary of the Invention

[0007] The purpose of this invention is to provide a high-strength overhead insulated cable, which aims to solve the problems of insufficient structural shear stability, interlayer peeling, and insufficient dynamic heat dissipation performance of cables under frequent thermal alternation conditions.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: a high-strength overhead insulated cable, comprising, from the inside out, a high-strength load-bearing core, a conductor, a filling layer, a first buffer layer, a metal thermally conductive layer, a second buffer layer, and an insulating sheath layer, wherein the first buffer layer is compressible and has an internal cavity, and a temperature-controlled bridging rib is provided within the cavity; the temperature-controlled bridging rib includes a temperature-sensing dynamic core near the inner side and a high thermal conductivity contact layer wrapping around the portion of the temperature-sensing dynamic core away from the filling layer;

[0009] The metal thermally conductive layer is an asymmetric composite metal layer that is dense on the inside and porous on the outside.

[0010] The second buffer layer integrates a phase change heat-absorbing material; the second buffer layer is provided with an anchor located on its inner side and a stress relief cavity located inside; the anchor and the metal heat-conducting layer form a mechanical interlocking structure.

[0011] Preferably, the second buffer layer has alternating static anchoring zones and stress relief zones along the circumferential direction, the stress relief cavity is located in the stress relief zone, and the anchor is located in the static anchoring zone.

[0012] Preferably, the anchor is a mechanically interlocking structure formed by the solidification of a polymer melt penetrating into the pores of the metal thermally conductive layer.

[0013] Preferably, the temperature-controlled bridging rib and the stress relief cavity of the second buffer layer are arranged in an overlapping and aligned manner in the radial projection; the temperature-controlled bridging rib and the anchor are arranged in an interlaced manner in the radial projection.

[0014] Preferably, the static anchoring zone is a solid structure without stress relief cavity to provide shear stiffness; when the temperature-controlled bridging rib expands radially and pushes the metal heat-conducting layer, the local deformation of the metal heat-conducting layer can fall into the area where the corresponding stress relief cavity is located.

[0015] Preferably, the temperature-sensitive dynamic core is made of a modified elastomer with a high coefficient of thermal expansion or a thermotropic shape memory polymer.

[0016] Preferably, when the local temperature reaches a preset threshold, the temperature-sensing power core undergoes radial volume expansion, driving the high thermal conductivity contact skin to extend radially towards the metal thermal conductivity layer, abutting against the inner wall of the metal thermal conductivity layer, and establishing a solid thermal conductivity path.

[0017] Preferably, both the filling layer and the first buffer layer are made of semi-conductive polymer composite material, so that the metal thermally conductive layer and the conductor form an electrically closed equipotential body, and the stress relief cavity is filled with high compression ratio insulating gel or insulating foamed microspheres.

[0018] Preferably, the phase change heat-absorbing material is a microencapsulated solid-liquid phase change material, which is uniformly doped into the matrix of the second buffer layer to absorb local heat load and smooth temperature fluctuations.

[0019] Preferably, the insulating sleeve is a high thermal conductivity insulating composite material, which tightly covers the outside of the second buffer layer. The matrix is ​​doped with insulating and thermally conductive filler. The outer surface of the insulating sleeve is integrally formed with micro heat dissipation grooves extending in the axial or spiral direction, which are used to dissipate internal heat to the external environment by convection.

[0020] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0021] This invention, through the setting of temperature-controlled bridging ribs and cavities within the first buffer layer, maintains air insulation within the cavity during low-load cable operation, effectively mitigating the frequency of temperature alternation between the environment and the interior. This significantly reduces the risk of matrix fatigue and interlayer delamination caused by high-frequency thermal expansion and contraction. When the load suddenly increases, the temperature-controlled bridging ribs automatically establish a solid heat transfer path, combined with phase change materials to smooth out sudden heat loads, achieving adaptive dynamic thermal management of the cable under all operating conditions. Simultaneously, the alternating arrangement of static anchors and stress relief cavities perfectly balances high shear anti-slip and radial thermal expansion absorption, overcoming industry bottlenecks such as thermal cycling fatigue, interlayer delamination, and thermal breakdown in high-load overhead cables, and greatly improving the cable's service life and safe current carrying capacity. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall cross-sectional structure of the present invention.

[0023] Figure 2 This is a partial schematic diagram of the first buffer layer, the metal heat-conducting layer, and the second buffer layer when the cable of the present invention is in a low-temperature state.

[0024] Figure 3 This is a partial schematic diagram of the first buffer layer, the metal heat-conducting layer, and the second buffer layer when the cable of the present invention is in a high-temperature state.

[0025] Figure label:

[0026] 1. High-strength load-bearing core; 2. Conductor; 3. Filler layer; 4. First buffer layer; 41. Cavity; 42. Temperature-controlled bridging rib; 421. Temperature-sensitive dynamic core; 422. High thermal conductivity contact skin layer; 5. Metal thermally conductive layer; 6. Second buffer layer; 61. Phase change heat-absorbing material; 62. Static anchoring zone; 621. Anchor; 63. Stress relief zone; 631. Stress relief cavity; 7. Insulating sleeve layer. Detailed Implementation

[0027] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1

[0029] To improve the structural shear stability, interlaminar peel resistance, and dynamic heat dissipation performance of overhead insulated cables under frequent thermal alternation conditions, such as... Figures 1 to 3 As shown, this invention proposes a high-strength overhead insulated cable, which consists of a high-strength carrying core 1, a conductor 2, a filling layer 3, a first buffer layer 4, a metal thermally conductive layer 5, a second buffer layer 6, and an insulating sheath 7 arranged sequentially from the inside out. The filling layer 3 and the conductor 2 can be made of materials with similar coefficients of thermal expansion. The high-strength carrying core 1, located at the very center, can be made of carbon fiber composite material or galvanized steel core, etc. The carbon fiber composite material core has extremely high tensile strength and extremely low coefficient of linear expansion, providing a basic mechanical tensile load for the cable to be installed over long spans. An aluminum conductor 2 is tightly twisted around the outside of the high-strength carrying core 1.

[0030] The first buffer layer 4 is wrapped around the outside of the filling layer 3, and the second buffer layer 6 is disposed between the metal heat-conducting layer 5 and the insulating sleeve layer 7; the metal heat-conducting layer 5 is an asymmetric composite metal layer that is dense on the inside and porous on the outside; the metal heat-conducting layer 5 can disperse local heat along the circumference and axial direction of the cable to form rapid cooling.

[0031] The first buffer layer 4 is compressible and has a cavity 41 arranged along the circumference of the cable inside. The cavity 41 has a temperature control bridging rib 42 facing the metal heat-conducting layer 5. The temperature control bridging rib 42 is a two-component co-extruded structure, including a temperature-sensing power core 421 near the inner side and a high thermal conductivity contact skin layer 422 wrapped around the top of the temperature-sensing power core 421.

[0032] The temperature-sensitive dynamic core 421 can be made of bimetallic strips, modified elastomers with high thermal expansion coefficients, thermotropic shape memory polymers, or bidirectional shape memory alloys.

[0033] When the local temperature of the cable reaches a preset threshold, the temperature-sensing power core 421 undergoes radial deformation, driving the high thermal conductivity contact skin 422 to move until it comes into contact with the inner wall of the metal thermal conductive layer 5, establishing a solid thermal conductive path.

[0034] The first buffer layer 4 may also be provided with tensile limiting wires arranged along the cable axis to enhance the overall tensile strength of the cable. The tensile limiting wires may be made of load-bearing units such as aramid fibers.

[0035] The compressibility of the first buffer layer 4 itself can absorb the internal expansion and compression; the cavity 41 in the first buffer layer 4 can prevent the cable from dissipating heat too quickly when the cable is used at low power and in a low temperature environment, and reduce the thermal stress fatigue caused by temperature alternation; it provides "breathing margin" for the radial volume change of the cable when the peak and valley loads alternate.

[0036] It should be noted that dynamic stress compensation is achieved through the cooperation of cavity 41 and temperature-controlled bridging rib 42.

[0037] During the high-load heating stage, the materials of each layer expand due to heat. The temperature-sensing power core 421 drives the high thermal conductivity contact skin layer 422 to move, which not only establishes a heat dissipation path, but also applies a uniform radial positive pressure to the external metal heat-conducting layer 5, eliminating the interlayer micro gaps caused by the difference in material expansion rate and preventing the structure from loosening.

[0038] During the low-load cooling phase, the materials in each layer shrink when cooled, which can easily cause interlayer tearing tension. At this time, the temperature-sensitive dynamic core 421 shrinks radially in sync with the temperature drop, actively giving up stress space. This effectively releases the huge interfacial tensile stress between the metal layer and the buffer layer caused by the difference in cooling and shrinkage, fundamentally eliminating the hidden dangers of interlayer tearing and peeling, and ensuring that the cable maintains its structural density and integrity after undergoing tens of millions of thermal cycles.

[0039] Furthermore, it completely overcomes the problems of thermal cycling fatigue and interlayer peeling failure of cables under intermittent operation; it utilizes the temperature-controlled bridging rib 42 and cavity 41 to form a dynamic thermal stress follow-up system; under the alternating working conditions of frequent temperature rise and fall of the cable, this structure can "expand and tighten when heated, and contract and release pressure when cooled", as if giving the inner layer of the cable the ability to breathe and regulate itself; moreover, after the cable temperature decreases, the solid heat dissipation channel is eliminated, and the temperature of cavity 41 gradually decreases, effectively preventing the tensile force generated between the layers when the cable rapidly contracts from the thermal expansion state, and preventing interlayer peeling due to rapid cooling and contraction; it effectively resolves the interface tearing problem caused by the mismatch of thermal expansion coefficients in multi-material composite cables, and while ensuring efficient heat conduction in all weather conditions, it significantly extends the mechanical service life of overhead cables under complex power grid loads.

[0040] Both the filling layer 3 and the first buffer layer 4 are made of semi-conductive polymer composite materials, such as cross-linked polyethylene or silicone rubber elastomer doped with conductive carbon black. Through the semi-conductive filling layer 3 and the first buffer layer 4, the entire internal region from the filling layer 3 to the metal heat-conducting layer 5 forms an electrically closed equipotential body with the central conductor 2. On the one hand, this eliminates the voltage division effect of the floating capacitor in the AC high-voltage electric field of the metal heat-conducting layer 5. On the other hand, it makes the cavity 41 inside the first buffer layer 4 located inside the equipotential Faraday cage, that is, there is no potential difference inside and outside the cavity 41, which fundamentally eliminates the partial discharge and corona phenomenon caused by electric field distortion in the cavity 41 or the edge of the metal layer, and ensures the electrical safety of the internal dynamic mechanical structure.

[0041] The stress relief cavity 631 is filled with high compression ratio insulating gel or insulating foamed microspheres. The second buffer layer 6 is now an insulating layer and is in a high voltage electric field. Filling with insulating gel completely eliminates the potential partial discharge hazard that may be caused by the original air cavity.

[0042] The first buffer layer 4, its internal cavity 41, and the temperature-controlled bridging rib 42 are formed by a multi-machine co-extrusion process in one synchronous extrusion. When the buffer layer matrix is ​​extruded to form the cavity 41, the two-component rib composed of the temperature-sensitive power core 421 and the high thermal conductivity contact skin 422 is just extruded from the micro-hole at the end of the pin and directly shaped inside the newly formed cavity 41. The extruder head will also leave tiny air holes inside during extrusion. At the same time as extrusion, a constant micro-positive pressure gas is continuously injected into the formed cavity 41 to ensure the formation of the cavity 41.

[0043] The temperature-controlled bridging rib 42 is a two-component co-extruded structure, including a temperature-sensitive dynamic core 421 near the inner side and a high thermal conductivity contact skin 422 wrapped on top of it. The temperature-sensitive dynamic core 421 produced by this method can be made of a modified elastomer with a high coefficient of thermal expansion or a thermotropic shape memory polymer.

[0044] The second buffer layer 6 is provided with an anchor 621 located on its inner side and a stress relief cavity 631 located inside it; the anchor 621 and the metal heat-conducting layer 5 form a mechanical interlocking structure; the second buffer layer 6 is alternately distributed with a static anchoring area 62 and a stress relief area 63 along the circumferential direction, the stress relief cavity 631 is located in the stress relief area 63, and the anchor 621 is located in the static anchoring area 62.

[0045] The anchor 621 is a mechanically interlocked structure formed by the polymer melt penetrating into the pores of the metal heat-conducting layer 5 and solidifying. The stress relief cavity 631 in the second buffer layer 6 can withstand the thermal expansion and compression of the metal heat-conducting layer 5 to completely absorb the radial pressure and prevent the outermost insulating layer 7 from cracking due to internal thermal expansion stress.

[0046] Since the metal heat-conducting layer 5 is an asymmetric composite metal layer that is dense on the inside and porous on the outside, the anchor 621 only penetrates into the outer porous structure and is blocked by the inner dense layer. Furthermore, the dense metal foil on the inner side of the metal heat-conducting layer 5 provides a smooth and continuous solid heat transfer surface for the temperature control rib 42, while the outer metal mesh provides mechanical interlocking, thus completely solving the process problem of extrusion penetration and blockage of the contact surface.

[0047] The temperature-controlled bridging rib 42 and the stress relief cavity 631 of the second buffer layer 6 can be arranged in an overlapping and aligned manner in the radial projection; the temperature-controlled bridging rib 42 and the anchor 621 can be arranged in an interlaced manner in the radial projection; the anchor 621 can also occupy only the outer part of the metal layer pores and not protrude from the inner wall of the metal layer, so as to prevent the heat conduction efficiency of the "solid heat conduction path" from being affected after the pores of the metal heat conduction layer 5 are filled.

[0048] The static anchoring zone 62 can be a solid structure without stress relief cavity 631 to provide shear stiffness; when the temperature control bridging rib 42 expands radially and pushes the metal heat-conducting layer 5, the local deformation of the metal heat-conducting layer 5 falls into the area of ​​the overlapping and aligned stress relief cavity 631, while the static anchoring zone 62 is not damaged by radial compression.

[0049] Anchor 621 is a mechanical interlocking structure formed when the polymer melt penetrates into the porous or pore-filled metal heat-conducting layer 5 from the outside to the inside during the melt extrusion molding of the second buffer layer 6. To avoid spatial interference, the temperature-controlled bridging rib 42 and anchor 621 can be arranged in an alternating manner in the radial projection.

[0050] When the local temperature reaches a preset threshold, the first buffer layer 4 is compressed to relieve the outward radial compression caused by the thermal expansion of the conductor 2 and the filling layer 3. At this time, the anchor 621 embedded in the pores of the metal heat-conducting layer 5 enhances the shear resistance to prevent interlayer slippage when the cable bends or is heated.

[0051] As the overall temperature of the internal system of the cable rises, the internal conductor 2 and each structural layer undergo outward radial thermal expansion. The metal heat-conducting layer 5 expands outward radially accordingly. The stress relief cavity 631 in the second buffer layer 6 is passively compressed by the outward expansion of the metal heat-conducting layer 5, thereby completely absorbing the radial thermal expansion stress and preventing the outermost insulation layer 7 from cracking due to internal expansion and compression. During this process, the static anchoring zone 62 maintains structural stability and maintains interlayer shear resistance.

[0052] During the heating and expansion phase, when the inner ribs abut against the metal heat-conducting layer 5, a local heat and stress concentration point will be formed at this point; while the stress relief cavity 41 directly opposite on the outside can provide the most direct radial relief space and phase change heat absorption buffer for this concentration point, realizing the synergy of precise heat conduction support on the inside and precise stress absorption on the outside, minimizing the risk of shear failure inside the structure.

[0053] When the cable is fully loaded, conductor 2 undergoes significant thermal expansion. Filler layer 3 compresses first buffer layer 4, which relieves the compressive pressure and prevents compression of metal thermally conductive layer 5. At this time, temperature-sensitive dynamic core 421 deforms due to heat, driving high thermal conductivity contact skin layer 422 to radially displace, approaching and contacting metal thermally conductive layer 5, providing uniform internal support positive pressure, eliminating micro-cracks caused by the difference in expansion rate between layers. Furthermore, the heat of conductor 2 is rapidly transferred from filler layer 3 to metal thermally conductive layer 5 through high thermal conductivity contact skin layer 422, and the metal thermally conductive layer 5 disperses the heat along the circumference and axial direction of the cable, resulting in rapid cooling. Simultaneously, the entire internal components of the cable expand outward as a whole due to heat. At this time, the stress relief cavity 41 directly opposite the outer side is passively compressed by the outward expansion of the metal layer, completely absorbing the radial thermal expansion stress and protecting the outermost insulation layer 7 from cracking. Meanwhile, the static anchoring zone 62 is not compressed and firmly grips the metal layer to provide shear resistance.

[0054] When the load decreases, the materials in each layer shrink due to cooling, which can easily cause interfacial tearing tensile stress. At this time, the temperature-sensitive dynamic core 421 actively shrinks and yields as the temperature decreases, restoring the "breathing margin" in the first buffer layer 4, releasing the huge tensile stress caused by the difference in cooling and contraction between the layers, and avoiding interlayer peeling. In addition, after the cable temperature decreases, the solid heat dissipation channel closes, and the cavity 41 gradually reduces the internal temperature of the cable, preventing interlayer peeling due to rapid cooling and contraction.

[0055] By alternatingly dividing the second buffer layer 6 into a static anchoring zone 62 and a stress relief cavity 41 along the circumference, the static anchoring zone 62 formed by the polymer melt penetrating the metal mesh provides excellent interlayer anti-slip shear force. At the same time, the stress relief cavity 41 and the inner layer's temperature control bridging rib 42 are overlapped and aligned in the radial projection. When the internal components are heated and undergo overall outward radial expansion, the outer cavity 41 is passively compressed, completely absorbing thermal stress and avoiding the outermost insulating layer 7 from being subjected to internal stress.

[0056] In this embodiment, by setting a semi-conductive polymer composite material of filling layer 3, first buffer layer 4 and second buffer layer 6, the metal thermally conductive layer 5 and the buffer layers on both sides are electrically connected to the central high-voltage conductor 2, forming a closed equipotential body. This eliminates the voltage division effect of the floating capacitor in the alternating electric field of the metal thermally conductive layer 5, and places all the internal chambers in a Faraday cage with no potential difference, eliminating corona and partial discharge phenomena in the cavity 41. At the same time, the metal thermally conductive layer 5 also serves as an inner semi-conductive shielding layer, homogenizing the external electric field and achieving perfect self-consistency in thermodynamics, mechanics and high-voltage electromagnetic design.

[0057] Example 2

[0058] In practical applications, phenomena such as instantaneous short circuits in the power grid, overload operation during peak-valley transitions, or extreme high-temperature weather often occur, causing a sudden and enormous heat load to be generated inside the cable. In such cases, relying solely on the solid conduction path described in Example 1 may not be sufficient to dissipate the surge in heat in time, leading to localized instantaneous overheating and causing accelerated aging or even thermal breakdown of the insulation layer.

[0059] To solve the above-mentioned technical problems, in another embodiment of the present invention, a phase change heat-absorbing material 61 is integrated in the second buffer layer 6. The phase change heat-absorbing material 61 is a microencapsulated solid-liquid phase change material, which is uniformly doped into the matrix of the second buffer layer 6 as insulating microparticles, or coated on the sidewall of the stress relief cavity 631, to absorb local heat load and smooth temperature fluctuations. The phase change heat-absorbing material 61 can be high-carbon paraffin encapsulated in microcapsules. It can absorb the heat inside the cable to "smooth out peaks and valleys" and cope with the sudden temperature rise caused by short-term high current.

[0060] The insulating layer 7 is a high thermal conductivity insulating composite material. Its matrix is ​​doped with insulating and thermally conductive fillers. The insulating layer 7 can be formed by cross-linked polyethylene or EPDM rubber as the matrix, and the interior is doped with hexagonal boron nitride or nano alumina insulating and thermally conductive fillers in a high proportion. The outer surface of the insulating layer 7 is integrally formed with micro heat dissipation grooves extending in the axial or spiral direction, which are used to dissipate the internal heat to the external environment by convection.

[0061] When the cable encounters a transient short circuit or a short-term extreme high current impact, the temperature control bridging rib has tightly abutted against the metal layer to establish a thermal path. The surge in internal heat load is conducted to the outside and absorbed by the phase change heat-absorbing material 61 in the second buffer layer 6. The phase change material undergoes a phase change from solid to liquid. During the isothermal period of the phase change, it absorbs a large amount of latent heat, thereby suppressing the temperature surge peak inside the cable and preventing local instantaneous overheating that could lead to thermal breakdown.

[0062] The slow-released heat after the phase change material "shaving off the peaks" and the heat from normal operation continuously conducted by the metal thermal conductive layer 5 are quickly conducted to the outermost surface of the cable through the high thermal conductivity insulation composite sheath. The micro heat dissipation grooves on the outer surface multiply the contact area between the cable and the outside air, achieving extremely efficient convective heat transfer. This constructs an adaptive dynamic thermal management closed loop with precise thermal conduction support on the inner side, phase change heat storage buffer in the middle, and continuous heat dissipation from the outer microgrooves, thereby improving the cable's safe current carrying capacity limit under complex weather and harsh operating conditions.

[0063] It should be noted that inside the cable, a reinforced solid heat conduction path is established by the thermally expanding high thermal conductivity contact skin 422 tightly contacting the metal thermally conductive layer 5, thus avoiding the air insulation layer. In the middle layer, the phase change heat-absorbing material 61 integrated in the second buffer layer 6 is used to "smooth out peaks and valleys" to absorb the sudden heat load brought by short-term high current. On the outside, a high thermal conductivity insulating composite material is used in conjunction with the micro heat dissipation grooves on the outer surface to achieve efficient convection heat dissipation. Combined with the axial and circumferential temperature uniformity of the metal thermally conductive layer 5, thermal breakdown caused by local instantaneous overheating is prevented, significantly improving the cable's shock resistance margin to extreme working conditions.

[0064] This invention, through the setting of temperature-sensing dynamic core 421 and high thermal conductivity contact skin layer 422, enables the temperature-sensing dynamic core 421 to spontaneously generate radial expansion when the local overload temperature rises to a preset threshold, establishing a reinforced solid heat conduction path from the inside out. Combined with the phase change heat absorption material 61 in the second buffer layer 6 to "smooth out peaks and valleys" to absorb sudden heat loads, and the high thermal conductivity substrate and micro heat dissipation grooves of the insulation layer 7, continuous convection dissipation of internal heat is achieved. The cable maintains a normal state under low power and automatically triggers heat dissipation under high load, enabling the overhead cable to achieve adaptive dynamic heat dissipation when the temperature fluctuates drastically. At the same time, the ingenious mechanical structure absorbs the destructive stress caused by thermal expansion, ensuring the structural integrity of the insulation layer and the heat conduction layer.

[0065] The above are merely preferred embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.

Claims

1. A high-strength overhead insulated cable, comprising a high-strength load-bearing core, a conductor, a filling layer, and an insulating sheath arranged sequentially from the inside out, characterized in that, Between the filler layer and the insulating sleeve layer, from the inside out, are sequentially provided a first buffer layer, a metal thermally conductive layer, and a second buffer layer. The first buffer layer body is compressible and has an internal cavity with a temperature-controlled bridging rib inside the cavity; the temperature-controlled bridging rib includes a temperature-sensing dynamic core near the inner side and a high thermal conductivity contact skin wrapping around the portion of the temperature-sensing dynamic core away from the filling layer. The metal thermally conductive layer is an asymmetric composite metal layer that is dense on the inside and porous on the outside. The second buffer layer integrates a phase change heat-absorbing material; the second buffer layer is provided with an anchor located on its inner side and a stress relief cavity located inside; the anchor and the metal heat-conducting layer form a mechanical interlocking structure.

2. The overhead insulated cable according to claim 1, characterized in that: The second buffer layer has alternating static anchoring zones and stress relief zones along the circumferential direction. The stress relief cavity is located in the stress relief zone, and the anchor is located in the static anchoring zone.

3. The overhead insulated cable according to claim 1, characterized in that: The anchor is a mechanically interlocking structure formed by the solidification of polymer melt penetrating into the pores of the metal thermally conductive layer.

4. The overhead insulated cable according to claim 1, characterized in that: The temperature-controlled bridging rib and the stress relief cavity of the second buffer layer are arranged in an overlapping and aligned manner in radial projection; the temperature-controlled bridging rib and the anchor are arranged in an alternating manner in radial projection.

5. The overhead insulated cable according to claim 2, characterized in that: The static anchoring zone is a solid structure and does not contain a stress relief cavity to provide shear stiffness; when the temperature-controlled bridging rib expands radially and pushes the metal heat-conducting layer, the local deformation of the metal heat-conducting layer can fall into the area where the corresponding stress relief cavity is located.

6. The overhead insulated cable according to claim 1, characterized in that: The temperature-sensitive dynamic core is made of a modified elastomer with a high coefficient of thermal expansion or a thermotropic shape memory polymer.

7. The overhead insulated cable according to claim 1, characterized in that: When the local temperature reaches a preset threshold, the temperature-sensing power core undergoes radial volume expansion, driving the high thermal conductivity contact skin to extend radially towards the metal thermal conductivity layer, abutting against the inner wall of the metal thermal conductivity layer, and establishing a solid thermal conductivity path.

8. The overhead insulated cable according to claim 1, characterized in that: Both the filling layer and the first buffer layer are made of semi-conductive polymer composite material, so that the metal thermally conductive layer and the conductor form an electrically closed equipotential body. The second buffer layer is made of insulating material and serves as the main insulating layer to cooperate with the insulating sleeve layer in bearing electrical stress. The stress relief cavity is filled with high compression ratio insulating gel or insulating foamed microspheres.

9. The overhead insulated cable according to claim 1, characterized in that: The phase change heat-absorbing material is a microencapsulated solid-liquid phase change material, which is uniformly doped into the matrix of the second buffer layer to absorb local heat load and smooth temperature fluctuations.

10. The overhead insulated cable according to claim 1, characterized in that: The insulating sleeve is a high thermal conductivity insulating composite material, which tightly covers the outside of the second buffer layer. Its matrix is ​​doped with insulating and thermally conductive filler. The outer surface of the insulating sleeve is integrally formed with micro heat dissipation grooves extending in the axial or spiral direction, which are used to dissipate internal heat to the external environment by convection.

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