A low-voltage cable for a new energy distribution network and a control method thereof

Abstract

The application relates to the technical field of cable structure, in particular to a low-voltage cable for a new energy power distribution network and a control method thereof, which comprises a sheath layer and a plurality of cable cores arranged on the inner side of the sheath layer, and the plurality of cable cores are distributed along the circumference of the sheath layer. Through the application, the problems of low support strength and low wire filling coefficient of traditional cables are effectively solved. The structure mode of the central column located in the middle and the conductive layer arranged on the outer side of the central column is used to effectively realize function division. The central column serves as the main stress framework and bears all mechanical stresses in the laying and operation processes, so that the external conductive layer does not need to consider the support function, thereby being able to focus on optimizing the conductive performance. The structure design effectively solves the problem that the conductive and stress-bearing functions are mixed and restricted in the traditional cable, and significantly improves the tensile strength and operation reliability of the cable in the scene of frequent bending or large-span laying.

Description

Technical Field

[0001] This invention relates to the field of cable structure technology, and in particular to a low-voltage cable for new energy distribution networks and its control method. Background Technology

[0002] Low-voltage cables typically refer to cables with a rated voltage of 1.8 / 3kV and below. They are key power transmission carriers connecting power sources and user-side loads in power distribution networks. With the rapid growth of new energy power generation and new electricity consumption demands, low-voltage cables are playing an increasingly important role in new energy power distribution network scenarios such as distributed photovoltaic grid connection interfaces, electric vehicle charging facilities, and energy storage system connections.

[0003] The core structure of existing low-voltage cables is mostly composed of several copper or aluminum conductors twisted together, wrapped with an insulation layer and a sheath layer. However, the cross-section of a single filament in a traditional conductive core is usually circular. After twisting, a large number of triangular gaps inevitably exist between the individual filaments. These gaps are only filled with air and do not participate in conduction, resulting in the actual conductive cross-section of the core being much smaller than its outline cross-section. The industry defines the ratio of the actual cross-sectional area of ​​the conductor to its outline cross-sectional area as the "fill factor". The fill factor of a circular compacted conductor is usually only about 0.75, which means that about 25% of the outline space is not effectively used for current transmission, resulting in low space utilization. In addition, the mechanical support function of existing cables mainly relies on the twisted conductors themselves. This design places high demands on the tensile strength and creep resistance of the conductors. Moreover, in scenarios with frequent bending or large spans, the support strength is relatively insufficient, and uneven stress can easily lead to conductor damage, affecting the safety of line operation. Summary of the Invention

[0004] This invention provides a low-voltage cable for new energy distribution networks and its control method, which can effectively solve the problems in the background art.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A low-voltage cable for a new energy distribution network includes an outer jacket and a plurality of cable cores disposed inside the outer jacket. The plurality of cable cores are distributed circumferentially along the outer jacket and are twisted together or arranged in parallel within the outer jacket. The cable core includes a central post located in the middle and a conductive layer located on the outer wall of the central post. The conductive layer is a multi-layer structure arranged coaxially. Each layer consists of several conductors distributed circumferentially around the central post. The conductors cooperate with the adjacent conductors in the same layer and / or the conductors in adjacent layers to form a complete plane of the conductive layer.

[0006] Furthermore, an inner isolation layer is provided between the central pillar and the conductive layer.

[0007] Furthermore, the inner isolation layer includes, from the inside out, an insulating and fireproof layer, an inner nonlinear electrical stress control layer, and an inner microcapsule buffer layer.

[0008] Furthermore, the two adjacent wires are connected by a snap-fit ​​structure, which includes a snap-fit ​​and a slot on the wire, and the snap-fit ​​cooperates with the slot on the adjacent wire.

[0009] Furthermore, the clips and slots between two adjacent conductors form a heat dissipation duct arranged along the axis of the cable core; A temperature measuring cable bundle is provided between several of the cable cores.

[0010] Furthermore, the outer jacket is provided with a plurality of retainers for fixing the cable core, and the outer jacket and the cable core are provided with an air return corridor; The cable core is provided with several air holes for connecting the heat dissipation duct and the return air corridor.

[0011] Furthermore, grooves are provided on one side of the conductor and on the inner insulating layer, and protrusions are provided on the other side of the conductor. The grooves and corresponding protrusions are used in conjunction.

[0012] Furthermore, in the conductive layer, several of the wires in each layer are twisted together, and the twisting directions of the wires in adjacent layers are opposite.

[0013] Furthermore, an outer isolation layer is provided on the outside of the conductive layer, and the pores pass through the outer isolation layer. The outer isolation layer is composed of an outer microcapsule buffer layer, an outer nonlinear electrical stress control layer and a heat dissipation layer arranged sequentially from the inside to the outside. The outer sheath consists of an inner sheath, a shielding layer, an armor layer, and an outer sheath arranged sequentially from the inside out.

[0014] A control method for low-voltage cables used in new energy distribution networks includes the following steps: S01: Run the temperature measuring cable to monitor the temperature data inside the cable core in real time; at the same time, run the external air pump to maintain a slight positive pressure airflow in the heat dissipation air duct. The airflow enters the return air corridor through the air hole and then flows back to form a continuous circulating cooling airflow. S02: Temperature data collected by the temperature measuring cable is transmitted to an external data acquisition unit via optical fiber or data bus. The data acquisition unit converts the optical or electrical signals into digital signals and then uploads them to the remote monitoring platform via Ethernet or wireless communication. S03: The remote monitoring platform displays, stores, and analyzes the received temperature data in real time, plots the temperature distribution curve of the entire cable, and records historical temperature change trends; S04: When the monitoring platform determines that the temperature of all monitoring points is lower than the set threshold T1, the current operating state is maintained, and the air pump runs at the base speed to maintain circulating cooling. S05: When the monitoring platform determines that the temperature of a certain section of cable core is continuously higher than T1 but lower than the alarm threshold T2, it is determined to be a load increase condition. The air pump speed is automatically adjusted to medium to high speed to increase the airflow in the heat dissipation duct and enhance local heat dissipation. S06: When the temperature at a certain monitoring point exceeds T2, the monitoring platform immediately issues an audible and visual alarm, accurately locates the abnormal point on the temperature distribution curve, and automatically records the time of the abnormality and the rate of temperature change. S07: Maintenance personnel locate the abnormal point based on the alarm information, check the cause of the fault on site and handle it; after the handling is completed, manually reset the alarm system to restore normal operation.

[0015] The technical solution of this invention can achieve the following technical effects: This design effectively solves the problems of low support strength and low conductor fill factor in traditional cables. By utilizing a central column located in the middle and a conductive layer set outside the central column, functional division of labor is effectively achieved. The central column, as the main load-bearing skeleton, bears all mechanical stress during laying and operation, allowing the outer conductive layer to focus on optimizing conductivity without having to perform support functions. This structural design effectively solves the problem of mixed and mutually restrictive conductive and load-bearing functions in traditional cables, significantly improving the tensile strength and operational reliability of cables in scenarios with frequent bending or large spans. The conductive layer adopts a multi-layer coaxial assembly structure, with each layer consisting of several conductors forming a complete plane. This eliminates the triangular gaps that inevitably exist when traditional circular conductors are twisted together, significantly increasing the proportion of metal material in the profile cross-section. This results in a larger effective conductive cross-section under the same outer diameter conditions and a more compact cable outer diameter under the same current carrying capacity requirements, saving insulation and sheathing materials and reducing the need for laying space.

[0016] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of a low-voltage cable used in a new energy distribution network. Figure 2 for Figure 1 Schematic diagram of the middle cable core; Figure 3 for Figure 2 Schematic diagram of the central column; Figure 4 for Figure 2 Schematic diagram of the middle conductive layer; Figure 5 for Figure 2 Schematic diagram of the structure of the inner and outer isolation layers; Figure 6 for Figure 4 Schematic diagram of the structure of the middle conductor; Figure 7 for Figure 2 Schematic diagram of the strabismus structure; Figure 8 for Figure 1 Oblique sectional view of the structure; Reference numerals: 100, outer sheath; 101, inner sheath; 102, shielding layer; 103, armor layer; 104, outer sheath; 200. Cable core; 201. Center post; 202. Conductive layer; 203. Conductor; 204. Insulating and fireproof layer; 205. Inner nonlinear electrical stress control layer; 206. Inner microcapsule buffer layer; 207. Clip; 208. Slot; 209. Heat dissipation duct; 210. Air hole; 211. Return air corridor; 212. Cage; 213. Groove; 214. Raised ridge; 215. Outer isolation layer; 216. Outer microcapsule buffer layer; 217. Outer nonlinear electrical stress control layer; 218. Heat dissipation layer; 219. Temperature measuring cable bundle. Detailed Implementation

[0019] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0020] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this specification is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0021] like Figures 1 to 4As shown, this application provides a low-voltage cable for a new energy distribution network, including an outer jacket 100 and a plurality of cable cores 200 disposed inside the outer jacket 100. The plurality of cable cores 200 are distributed circumferentially along the outer jacket 100, and the plurality of cable cores 200 are twisted together or arranged in parallel inside the outer jacket 100. The cable core 200 includes a central post 201 located in the middle and a conductive layer 202 located on the outer wall of the central post 201. The conductive layer 202 is a multi-layer structure arranged coaxially. Each layer consists of several conductors 203 distributed circumferentially around the central post 201. The conductors 203 cooperate with the adjacent conductors 203 in the same layer and / or the conductors 203 in the adjacent layers to form a complete plane of the conductive layer 202.

[0022] Specifically, the outer jacket 100 can protect and support several cable cores 200 inside, which are mainly used for power transmission. The cable cores 200 in the outer jacket 100 have the two arrangements mentioned above. When the cable cores 200 are arranged in a twisted manner, it can significantly improve the overall flexibility and bending fatigue resistance of the cable. When the cable needs to be bent frequently or bear dynamic torsional loads during the laying process, the twisted structure allows each cable core 200 to generate relative displacement when bending, thereby dispersing mechanical stress and preventing a cable core 200 from breaking due to long-term tension. In addition, the twisted arrangement can make each cable core 200 uniformly transpose in the cable length direction, which can offset the circulating current loss caused by uneven magnetic field distribution to a certain extent. It is particularly suitable for application scenarios that require frequent movement or vibration, such as charging pile cables, mobile energy storage equipment connection cables, and wiring areas with frequent torsional loads in wind turbine generator sets.

[0023] In contrast, the parallel straight-line arrangement refers to multiple cable cores 200 arranged parallel to each other along the cable axis without spiral twisting. Their relative positions are fixed by filler material. The outstanding advantage of this structure is that the cable core 200 path is the shortest and completely straight, effectively avoiding the increase in the actual length of the cable core 200 caused by twisting, thereby reducing the DC resistance of the conductor and material consumption. At the same time, the parallel structure is more conducive to the uniform outward conduction of heat generated by each cable core 200 along the radial direction, avoiding the problem of heat accumulation in the central area of ​​the twisted structure, resulting in better heat dissipation performance. In addition, the parallel straight-line arrangement is simpler in manufacturing process, with high positioning accuracy of the cable core 200, which facilitates the uniform coverage of multi-layer shielding structures. This structure is particularly suitable for long-distance power transmission scenarios with fixed laying, high current carrying capacity requirements and low bending requirements, such as DC busbars inside photovoltaic power plants, fixed connections between battery clusters in energy storage systems, and trunk cables pre-embedded in buildings.

[0024] The center post 201 is located at the center of the cable core 200. As the skeleton of the cable and the cable core 200, it mainly bears all the tension during laying and operation, ensuring that the cable is not strained or broken when repeatedly bent or laid over a long span. This achieves "functional division of labor" and solves the problem of difficulty in balancing flexibility and strength caused by the traditional copper / aluminum conductors that both bear force and conduct electricity. The center post 201 can be made of carbon fiber composite material. The conductive layer 202 has a multi-layer structure, which can be regarded as multiple rings. Multiple rings are sequentially nested along the radial direction of the center post 201, with the innermost ring nested on the center post 201. In this way, the conductive layer 202 forms a complete circular planar shape, and all positions on the surface of this ring can be used for power transmission, which greatly improves the fill factor.

[0025] The combination of several conductors 203 into the conductive layer 202 facilitates the overall processing and assembly of the cable core 200. The conductors 203 can cooperate with adjacent conductors 203 in the same layer, thus increasing the strength between the conductors 203 in each layer and reducing the connection between adjacent layers while preventing interference. The conductors 203 can also cooperate with conductors 203 in adjacent layers, thus improving the connection between different layers. The conductors 203 can also cooperate with conductors 203 in the same layer and conductors 203 in adjacent layers simultaneously, thus improving the overall integrity and strength of the conductive layer 202. The cross-sectional shape of the conductors 203 can be any shape that can be combined, such as trapezoids or inclined quadrilaterals.

[0026] The technical solution of this invention effectively solves the problems of low support strength and low conductor fill factor in traditional cables. By utilizing the structure of a central column 201 located in the middle and a conductive layer 202 set on the outside of the central column 201, functional division of labor is effectively achieved. The central column 201, as the main load-bearing skeleton, bears all mechanical stress during laying and operation, so that the outer conductive layer 202 does not need to take on the support function, thus focusing on optimizing conductivity. This structural design effectively solves the problem of mixed and mutually restrictive conductive and load-bearing functions in traditional cables, significantly improving the tensile strength and operational reliability of cables in frequent bending or large-span laying scenarios. The conductive layer 202 adopts a multi-layer coaxial set structure, and each layer is formed by several conductors 203 working together to form a complete plane, eliminating the triangular gaps that inevitably exist when traditional round conductors 203 are twisted, significantly increasing the proportion of metal material in the profile cross-section, thereby achieving a larger effective conductive cross-section under the same outer diameter conditions, and achieving a more compact cable outer diameter under the same current carrying capacity requirements, which saves insulation and sheathing materials and reduces the need for laying space.

[0027] Furthermore, an inner isolation layer is provided between the central pillar 201 and the conductive layer 202.

[0028] When the central column 201 is made of carbon fiber composite material, since the conductive layer 202 needs to conduct electricity, there is a significant difference between the surface state of the central column 201 and the conductive layer 202. Direct contact between the central column 201 and the conductive layer 202 can easily form local electric field distortion points. At this time, the inner isolation layer can tightly wrap the central column 201, so that the inner wall of the conductive layer 202 obtains a smooth and uniform electric field equipotential surface, eliminating the electric field concentration caused by the difference in dielectric constant of the two materials or the unevenness of the surface of the bearing layer, thereby effectively suppressing partial discharge and improving the long-term reliability of the insulation system.

[0029] In addition, the inner insulation layer can also have heat insulation and buffering functions to facilitate the application of the coefficient mismatch when the cable is bent or when it expands and contracts due to heat, and reduce the generation of shear force.

[0030] Furthermore, such as Figure 3 As shown, the inner isolation layer includes an insulating and fireproof layer 204, an inner nonlinear electrical stress control layer 205, and an inner microcapsule buffer layer 206 arranged sequentially from the inside to the outside.

[0031] The insulating and fireproof layer 204, as the innermost layer, directly covers the surface of the central post 201. Its primary function is to achieve electrical isolation and thermal management. If the central post 201 is made of high-strength non-metallic materials such as carbon fiber composites, its surface may have certain conductivity or dielectric properties. When it comes into direct contact with the subsequent conductive layer 202, it may cause interface charge accumulation or partial discharge. The insulating and fireproof layer 204 uses insulating materials with high volume resistivity and high thermal stability, such as polyimide film or high-temperature cross-linked polyolefin, which can ensure reliable electrical insulation strength between the central post 201 and the conductive layer 202, preventing leakage current from forming a path through the central post 201. At the same time, this layer material should also have low thermal conductivity, which can effectively block the heat generated by the conductive layer 202 during operation from being conducted into the cable, avoiding material aging or performance deterioration of the central post 201 due to long-term heating, thereby protecting the cable's "skeleton" to maintain stable mechanical support capabilities for a long time.

[0032] The inner nonlinear electric stress control layer 205, located in the middle, is the core functional layer for solving the problem of electric field concentration. This layer uses a polymer-based composite material with added nonlinear conductive fillers such as silicon carbide and zinc oxide. It has the characteristic of automatically adjusting resistivity according to changes in electric field strength. Under normal operating voltage, this layer exhibits a high resistance state and has little impact on the electric field distribution. When the local electric field strength abnormally increases due to factors such as differences in material dielectric constant, surface burrs, or external overvoltage at the interface, the resistivity of this layer material rapidly decreases, forming a local conductive path, which allows the concentrated charge to be dispersed, thereby smoothing the steep potential gradient. This dynamic response mechanism can effectively suppress the electric field distortion caused by the difference in material properties between the central pillar 201 and the conductive layer 202, and eliminate the causes of partial discharge.

[0033] The inner microcapsule buffer layer 206, as the outermost layer, is in direct contact with the conductive layer and mainly serves as a buffer for mechanical stress and an auxiliary function for thermal management. This layer uses a flexible polymer as its matrix and uniformly disperses encapsulated phase change materials, such as paraffin and fatty acids, inside. In terms of mechanical properties, the low modulus of this layer enables it to effectively absorb the relative displacement and mechanical stress of the conductive layer caused by bending, thermal expansion and contraction, or external impact, preventing rigid friction or extrusion damage between the conductive layer monofilaments and the inner layer structure. In terms of thermal management, when the cable experiences a short-term overload that causes the temperature of the conductive layer to rise, the phase change material inside the microcapsule absorbs heat and undergoes a phase change, storing the heat as latent heat, thereby slowing down the rate of temperature rise and protecting the insulating and fireproof layer 204 from instantaneous thermal shock. When the load decreases and the temperature drops, the phase change material releases the stored heat, achieving dynamic balance regulation of heat.

[0034] Furthermore, two adjacent conductors 203 are connected by a snap-fit ​​structure, which includes a snap-fit ​​207 and a slot 208 disposed on the conductor 203. The snap-fit ​​207 is used in conjunction with the slot 208 on the adjacent conductor 203.

[0035] When two adjacent wires 203 in the same layer of conductive layer 202 are used together, such as Figure 6 As shown, the buckle 207 and the slot 208 are located on the left and right sides of the conductor 203, respectively. The buckle 207 on one conductor 203 is inserted into the slot 208 on another conductor 203, thereby connecting several conductors 203 in the same layer together in sequence, improving the connection strength. When two conductors 203 in adjacent layers of the conductive layer 202 are used together, the buckle 207 and the slot 208 can be located on the upper and lower sides of the conductor 203, and the combination of two conductors 203 in different layers can be achieved by relying on the buckle 207 and the slot 208. When the conductor 203 is used in combination with the adjacent conductor 203 in the same layer and the conductor 203 in the adjacent layer, two buckles 207 and two slots 208 will be provided on the conductor 203, that is, the conductor 203 in the middle can be used in combination with all the conductors 203 around it.

[0036] Furthermore, the clips 207 and slots 208 between two adjacent conductors 203 form a heat dissipation duct 209 arranged along the axial direction of the cable core 200; Temperature measuring bundles 219 are installed between several cable cores 200.

[0037] like Figure 1 As shown, the temperature measuring cable bundle 219 is located at the center of several cable cores 200, and the distance between it and each cable core 200 is equal. The main function of the temperature measuring cable bundle 219 is to perform real-time, continuous, multi-point or distributed accurate monitoring of the internal temperature of the cable, thereby providing core data support for the dynamic management of the cable's current carrying capacity and early warning of faults.

[0038] Temperature sensing cable 219 typically employs a dedicated cable structure with built-in temperature sensors. Multiple temperature sensors are spaced apart along its length, or a continuous distributed temperature-sensing optical fiber is used. When a multi-point sensor structure is employed, multiple digital temperature sensor chips can be encapsulated within the cable 219, outputting temperature signals via a bus. When a distributed optical fiber structure is used, the Raman scattering effect of the optical fiber is utilized to achieve temperature sensing at every point along the entire line, offering significant advantages such as resistance to electromagnetic interference, insulation withstand voltage, and high positioning accuracy. The temperature sensing cable 219 is tightly laid between the cable cores, directly sensing temperature fluctuations in the cable conductor caused by load changes or local anomalies during operation, capturing potential overheating hazards immediately. The temperature sensing cable 219 can form a complete intelligent temperature monitoring network with an external monitoring system.

[0039] like Figure 6 As shown, when the buckle 207 is combined with the slot 208, the buckle 207 can occupy only part of the space in the slot 208. The remaining space in the slot 208 is used as a heat dissipation duct 209. The heat dissipation duct 209 is connected to an external air pump or other air supply structure. When the temperature measuring cable 219 detects an abnormal internal temperature of the cable, room temperature gas or cold air can be introduced into the heat dissipation duct 209 to achieve the purpose of cooling the conductor 203 and ensuring that the conductive layer 202 can operate stably for a long time within the specified temperature range.

[0040] Furthermore, the outer jacket 100 is provided with several retainers 212 for fixing the cable core 200, and the outer jacket 100 and the cable core 200 are provided with a return air corridor 211. The cable core 200 is provided with several air holes 210 for connecting the heat dissipation air duct 209 and the return air corridor 211.

[0041] like Figures 7 to 8 As shown, several cable cores 200 are fixed to the inner wall of the outer jacket 100 by several retainers 212. Part of the space inside the outer jacket 100 is used to house the cable cores 200, and the remaining space can be used as a return air corridor 211. At the same time, the retainers 212 do not obstruct the return air corridor 211. When the heat dissipation duct 209 is ventilated, the gas in the heat dissipation duct 209 can be discharged into the return air corridor 211 through several air holes 210. The gas in the return air corridor 211 then flows back to the air supply end of the heat dissipation duct 209, thereby realizing the fixed-point return of airflow. The gas flowing back in the return air corridor 211 can cool the internal space of the outer jacket 100 and the surface of the cable cores 200.

[0042] Furthermore, grooves 213 are provided on one side of the conductor 203 and on the inner insulating layer, and protrusions 214 are provided on the other side of the conductor 203. The grooves 213 and the corresponding protrusions 214 are used in conjunction.

[0043] To improve the connection strength between the conductive layer 202 and the inner isolation layer, prevent the conductive layer 202 from moving relative to the inner isolation layer along the circumference of the inner isolation layer, and improve the connection between adjacent layers within the conductive layer 202 to prevent misalignment and slippage of different layers, the aforementioned groove 213 and protrusion 214 structure can be adopted. When the protrusion 214 is inserted into the corresponding groove 213, the inner isolation layer can position the innermost structure within the conductive layer 202, and different layers within the conductive layer 202 can interlock with each other, thereby further improving the robustness and overall strength of the cable core 200.

[0044] The inner isolation layer has several grooves 213.

[0045] Furthermore, in the conductive layer 202, several wires 203 in each layer are twisted together, and the twisting directions of the wires 203 in adjacent layers are opposite.

[0046] The twisting of several conductors 203 together can improve the overall strength of each layer in the conductive layer 202. At the same time, by making the twisting directions of adjacent layers opposite, the torsional torque can be offset, so that the cable as a whole maintains torque balance when under stress, which significantly improves the torsional stability and stress uniformity of the structure. Meanwhile, the reverse twisting makes the conductors 203 of adjacent layers move in opposite directions, which restricts each other and keeps them in their respective tracks during bending, thereby maintaining the structural integrity and cross-sectional shape of the conductive layer 202 and preventing loosening or local protrusion.

[0047] Because the wires 203 are twisted together, the protrusions 214 on the outer wall of the inner wires 203 in the conductive layer 202 are composed of multiple inclined grooves that are inclined relative to the wires 203. This allows the protrusions 214 to be used in conjunction with the grooves 213 on the outer wires 203.

[0048] Furthermore, an outer isolation layer 215 is provided on the outside of the conductive layer 202, and the pores 210 pass through the outer isolation layer 215. The outer isolation layer 215 is composed of an outer microcapsule buffer layer 216, an outer nonlinear electrical stress control layer 217 and a heat dissipation layer 218 arranged sequentially from the inside to the outside. The outer sheath 100 consists of an inner sheath 101, a shielding layer 102, an armor layer 103, and an outer sheath 104 arranged sequentially from the inside to the outside.

[0049] like Figure 1 , Figure 3 and Figure 5 As shown, the inner microcapsule buffer layer 206 and the outer microcapsule buffer layer 216 work together to buffer the conductive layer 202 from both the inner and outer sides; the inner nonlinear electric stress control layer 205 and the outer nonlinear electric stress control layer 217 work together to deal with the electric field distortion generated on the conductive layer 202 from both the inner and outer sides, and eliminate partial discharge.

[0050] The heat dissipation layer 218 is a key structure in the outer isolation layer 215 that has both thermal management and mechanical support functions. This layer can be made of composite materials with high thermal conductivity, such as thermally conductive silicone filled with thermally conductive fillers such as boron nitride and alumina, or wrapped with metal-polymer composite tape with heat dissipation fins. Its core function is to efficiently conduct the heat generated by the conductive layer 202, exchange heat through a large heat dissipation surface area, and reduce the operating temperature of the cable core 200. At the same time, this layer has a certain mechanical strength and rigidity.

[0051] The inner sheath 101 is usually extruded from materials such as low-smoke halogen-free flame-retardant polyolefin or polyvinyl chloride. Its primary function is to provide auxiliary support for the various structures within the outer sheath 100, preventing relative displacement of the structural units when bending or under stress. At the same time, the inner sheath 101 provides basic waterproof, moisture-proof and corrosion-proof protection.

[0052] The shielding layer 102 adopts a structure such as copper tape wrapping, copper wire braiding, or aluminum-plastic composite tape. Its main function is to suppress electromagnetic interference. On the one hand, it prevents the electromagnetic field generated by the current transmitted inside the cable from interfering with sensitive external equipment. On the other hand, it resists the interference of the external electromagnetic environment on the internal signals of the cable. For the high-frequency harmonics generated by a large number of power electronic devices in the new energy distribution network, the shielding layer 102 can provide an effective electromagnetic shielding path.

[0053] The armor layer 103 is the core structure for the mechanical protection of the cable. It is usually made of galvanized steel strip, stainless steel strip or aluminum alloy strip spirally wrapped or interlocked. Its core function is to resist direct mechanical damage during laying and use, such as squeezing, impact, tension or rodent bites.

[0054] The outer sheath 104 is the outermost layer of the cable that is directly exposed to the external environment. It is usually made of highly weather-resistant materials, such as ceramicized silicone rubber, high-density polyethylene, or low-smoke halogen-free flame-retardant polyolefin. Its primary function is to resist the attack of environmental factors such as ultraviolet radiation, humidity, salt spray, and chemical corrosion, and to protect the internal structure from environmental influences.

[0055] By utilizing the inner isolation layer, the outer isolation layer 215, and the outer jacket layer 100, a three-level protection system from the inside out can be formed to ensure that the cable can be used stably for a long time.

[0056] A control method for low-voltage cables used in new energy distribution networks includes the following steps: S01: The temperature measuring cable 219 is operated to monitor the temperature data inside the cable core 200 in real time; at the same time, the external air pump is operated to maintain a slight positive pressure airflow in the heat dissipation air duct 209. The airflow enters the return air corridor 211 through the air hole 210 and then flows back, forming a continuous circulating cooling airflow. S02: Temperature data collected by temperature measuring cable 219 is transmitted to an external data acquisition unit via optical fiber or data bus. The data acquisition unit converts the optical or electrical signals into digital signals and then uploads them to the remote monitoring platform via Ethernet or wireless communication. S03: The remote monitoring platform displays, stores, and analyzes the received temperature data in real time, plots the temperature distribution curve of the entire cable, and records historical temperature change trends; S04: When the monitoring platform determines that the temperature of all monitoring points is lower than the set threshold T1, the current operating state is maintained, and the air pump runs at the base speed to maintain circulating cooling. S05: When the monitoring platform determines that the temperature of a certain section of cable core 200 is continuously higher than T1 but lower than the alarm threshold T2, it is determined to be a load increase condition. The air pump speed is automatically adjusted to medium to high speed to increase the airflow in the heat dissipation duct 209 and enhance local heat dissipation. S06: When the temperature at a certain monitoring point exceeds T2, the monitoring platform immediately issues an audible and visual alarm, accurately locates the abnormal point on the temperature distribution curve, and automatically records the time of the abnormality and the rate of temperature change. S07: Maintenance personnel locate the abnormal point based on the alarm information, check the cause of the fault on site and handle it; after the handling is completed, manually reset the alarm system to restore normal operation.

[0057] The above method makes full use of the structural characteristics of the cable itself (heat dissipation duct, return air corridor, temperature measurement cable bundle, etc.) to build a cable thermal management system that integrates real-time monitoring, intelligent control, active heat dissipation, and fault early warning. It significantly improves the operational safety, reliability, and intelligence level of low-voltage cables used in new energy distribution networks, and has significant technological progress and practical value.

[0058] Although this application has been described in conjunction with specific features and embodiments, it is obvious that various modifications and combinations can be made thereto without departing from the spirit and scope of this application. Accordingly, this specification and drawings are merely exemplary illustrations of the application as defined herein, and are to be considered as covering any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from its scope. Thus, if such modifications and modifications fall within the scope of this application and its equivalents, this application intends to include such modifications and modifications.

Claims

1. A low-voltage cable for a new energy distribution network, characterized in that, It includes an outer layer and a plurality of cable cores disposed inside the outer layer. The plurality of cable cores are distributed circumferentially along the outer layer and are twisted together or arranged in parallel within the outer layer. The cable core includes a central post located in the middle and a conductive layer located on the outer wall of the central post. The conductive layer is a multi-layer structure arranged coaxially. Each layer consists of several conductors distributed circumferentially around the central post. The conductors cooperate with the adjacent conductors in the same layer and / or the conductors in adjacent layers to form a complete plane of the conductive layer. An inner isolation layer is provided between the central pillar and the conductive layer; The inner isolation layer includes, from the inside out, an insulating and fireproof layer, an inner nonlinear electrical stress control layer, and an inner microcapsule buffer layer; The two adjacent wires are connected by a snap-fit ​​structure, which includes a snap-fit ​​and a slot on the wire, and the snap-fit ​​cooperates with the slot on the adjacent wire. The clips and slots between two adjacent conductors form a heat dissipation duct arranged along the axis of the cable core. A temperature measuring cable bundle is provided between several of the cable cores; The outer jacket is provided with a plurality of retainers for fixing the cable core, and the outer jacket and the cable core are provided with a return air corridor. The cable core is provided with several air holes for connecting the heat dissipation duct and the return air corridor.

2. The low-voltage cable for a new energy distribution network according to claim 1, characterized in that, The conductor has a groove on one side and the inner insulating layer, and the conductor has a ridge on the other side. The groove and the corresponding ridge are used in conjunction.

3. The low-voltage cable for a new energy distribution network according to claim 1, characterized in that, The conductive layers contain several wires that are twisted together in each layer, and the twisting directions of the wires in adjacent layers are opposite.

4. The low-voltage cable for a new energy distribution network according to claim 1, characterized in that, An outer isolation layer is provided on the outside of the conductive layer, and the pores pass through the outer isolation layer. The outer isolation layer is composed of an outer microcapsule buffer layer, an outer nonlinear electrical stress control layer and a heat dissipation layer arranged sequentially from the inside to the outside. The outer sheath consists of an inner sheath, a shielding layer, an armor layer, and an outer sheath arranged sequentially from the inside out.

5. A control method for a low-voltage cable used in a new energy distribution network, employing a low-voltage cable for a new energy distribution network as described in any one of claims 1-4, characterized in that, Includes the following steps: S01: Run the temperature measuring cable to monitor the temperature data inside the cable core in real time; at the same time, run the external air pump to maintain a slight positive pressure airflow in the heat dissipation air duct. The airflow enters the return air corridor through the air hole and then flows back to form a continuous circulating cooling airflow. S02: Temperature data collected by the temperature measuring cable is transmitted to an external data acquisition unit via optical fiber or data bus. The data acquisition unit converts the optical or electrical signals into digital signals and then uploads them to the remote monitoring platform via Ethernet or wireless communication. S03: The remote monitoring platform displays, stores, and analyzes the received temperature data in real time, plots the temperature distribution curve of the entire cable, and records historical temperature change trends; S04: When the monitoring platform determines that the temperature of all monitoring points is lower than the set threshold T1, the current operating state is maintained, and the air pump runs at the base speed to maintain circulating cooling. S05: When the monitoring platform determines that the temperature of a certain section of cable core is continuously higher than T1 but lower than the alarm threshold T2, it is determined to be a load increase condition. The air pump speed is automatically adjusted to medium to high speed to increase the airflow in the heat dissipation duct and enhance local heat dissipation. S06: When the temperature at a certain monitoring point exceeds T2, the monitoring platform immediately issues an audible and visual alarm, accurately locates the abnormal point on the temperature distribution curve, and automatically records the time of the abnormality and the rate of temperature change. S07: Maintenance personnel locate the abnormal point based on the alarm information, check the cause of the fault on site and handle it; after the handling is completed, manually reset the alarm system to restore normal operation.

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