10kV medium-voltage fireproof flame-retardant cable

Abstract

The utility model discloses a 10kV medium-voltage fire-resistant flame-retardant cable, which comprises a cable core and an outer sheath wrapped on the outer layer of the cable core, the cable core comprises a plurality of wire cores and fillers, and the structure of each wire core sequentially comprises a conductor, a shielding layer, an insulating layer, an insulating shielding layer, a first wrapping tape, a metal shielding layer and a copper tape from inside to outside; the structure of the outer sheath comprises two metal layers. The cable is reasonable in structural design, and has the following beneficial effects: the two metal layers are arranged, and the water channel is arranged between the two metal layers, so that the heat dissipation capability and the flame-retardant fireproof performance of the cable are enhanced, the cable is helped to dissipate heat, the normal working temperature of the cable is maintained, the current-carrying capability of the cable is improved, and the service life of the cable is prolonged. And therefore, stable operation can be realized under relatively high current. And meanwhile, a gear sleeve structure is arranged, so that the bonding strength can be improved, deformation and displacement can be adapted, certain flexibility and adaptability are provided, the connection stability is improved, and good bonding with the metal layer is maintained.

Description

Technical Field

[0001] The utility model relates to the technical field of cables, in particular to a 10kV medium-voltage fire-resistant and flame-retardant cable. Background Technique

[0002] With the emergence of an increasing number of high-rise buildings and large-scale projects, in the fire protection loop system, low-voltage cables can no longer meet the requirements of line voltage drop. Moreover, due to the fact that the fire-resistant structure design of traditional low-voltage cables is to add an inorganic fire-resistant layer outside the conductor, this structure can be used for cables with relatively low voltage levels. However, for medium-voltage cables, due to their relatively high voltage levels, relying on the electrical insulation performance of mica cannot meet the insulation requirements of medium-voltage cables, and a fire-resistant layer cannot be directly arranged outside the conductor.

[0003] Therefore, at present, there is a need for a cable that can not only solve the power supply problem of the entire fire protection loop but also meet the corresponding fire protection requirements, and can maintain the normal operation of the power system for a certain period of time in case of a fire, winning more valuable time for personnel evacuation and fire rescue. Content of the Utility Model

[0004] The purpose of the utility model is to provide a 10kV medium-voltage fire-resistant and flame-retardant cable, which solves the power supply problem of the fire protection loop and meets the corresponding fire protection requirements at the same time.

[0005] In order to achieve the above purpose, the technical solution of the utility model provides a 10kV medium-voltage fire-resistant and flame-retardant cable, including a cable core and an outer sheath wrapped around the outer layer of the cable core. The cable core includes a plurality of wire cores and a filler. The structure of the wire core from the inside to the outside is successively a conductor, a shielding layer, an insulating layer, an insulation shielding layer, a first tape, a metal shielding layer, and a copper tape; the structure of the outer sheath includes two metal layers.

[0006] Further, the structure of the outer sheath from the inside to the outside is successively a third tape, a fourth tape, a waterproof layer, a first metal layer, an oxygen isolation layer, a second metal layer, a fire protection layer, and an outer protection layer.

[0007] Further, the cable core further includes a second tape. The number of wire cores is 3, and the 3 wire cores are symmetrically distributed in a triangular shape. The second tape wraps and fixes the positions of the wire cores relative to each other.

[0008] Further, the conductor is a Class 2 compact round copper conductor; the shielding layer is a semi-conductive rubber inner shielding layer; the insulating layer is an ethylene propylene rubber insulating layer; the insulation shielding layer is a semi-conductive rubber outer shielding layer.

[0009] Further, the first wrapping tape is a water-blocking tape, and two layers of the water-blocking tapes are overlapped and mechanically wrapped, with the overlapping rate of each layer being 15%-25%; the metal shielding layer is a copper wire shielding layer, and the copper wire shielding layer is loosely wound and shielded with 0.85 mm soft round copper wires; the copper tape has a reverse binding structure.

[0010] Further, the second wrapping tape is two layers of low-smoke, halogen-free and highly flame-retardant tapes overlapped and mechanically wrapped, with the overlapping rate of each layer being 20%-30%; the filler is a flame-retardant high-temperature filling rope.

[0011] Further, the third wrapping tape is a double-sided water-blocking tape, and two layers of the water-blocking tapes are overlapped and mechanically wrapped, with the overlapping rate of each layer being 15%-25%; the fourth wrapping tape is an aluminum-plastic tape, and the aluminum-plastic tape is longitudinally wrapped, with the overlapping rate being 10%-20%.

[0012] Further, the waterproof layer is a layer of flame-retardant polyethylene layer, and the waterproof layer has a tooth sleeve structure, with the teeth protruding from the inner layer to the outer layer, and the inner layer of the waterproof layer being a smooth structure; the first metal layer is a corrugated aluminum sheath, welded to the outer layer of the waterproof layer.

[0013] Further, the oxygen barrier layer is a layer of low-smoke, halogen-free polyethylene layer, and the oxygen barrier layer has a tooth sleeve structure, with the teeth protruding from the inner layer to the outer layer, and the inner layer of the oxygen barrier layer being a smooth structure; the second metal layer is a corrugated aluminum sheath, welded to the outer layer of the oxygen barrier layer; the space between the oxygen barrier layer and the two metal layers before and after is a water channel, and the water channel can be provided with flowing cooling water.

[0014] Further, the fireproof layer is a layer of polyamide layer; the outer protective layer is a layer of silicone rubber layer. In summary, the device structure of the present utility model is reasonably designed. By applying the technical solution of the present utility model, the following beneficial effects are achieved: there are two metal layers provided, and at the same time, a water channel is provided between the two metal layers, enhancing the heat dissipation capacity and flame-retardant and fireproof performance of the cable, helping the cable to dissipate heat, maintaining its normal working temperature, thereby improving the current-carrying capacity of the cable and enabling it to operate stably under a higher current. At the same time, a tooth sleeve structure is provided, which can enhance the sealing and waterproof performance, improve the bonding strength, adapt to deformation and displacement, the tooth sleeve design can provide a certain degree of flexibility and adaptability, evenly distribute the pressure, increase the connection stability, adapt to the structural changes, and maintain a good combination with the metal layer. Brief Description of the Drawings

[0015] Figure 1 is a schematic cross-sectional structure diagram of the 10 kV medium-voltage fire-resistant and flame-retardant cable of the present utility model;

[0016] Explanation of the reference numerals: 1-conductor; 2-shielding layer; 3-insulating layer; 4-insulating shielding layer; 5-first wrapping tape; 6-metal shielding layer; 7-copper tape; 8-second wrapping tape; 9-filler; 10-third wrapping tape; 11-fourth wrapping tape; 12-waterproof layer; 13-first metal layer; 14-oxygen barrier layer; 15-second metal layer; 16-fireproof layer; 17-outer protective layer. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention, but this does not constitute a limitation on the protection scope of the present invention.

[0018] In this utility model, for a clearer description, the following explanation is made: the observer faces the Figure 1 For observation, the left front side of the observer is set as front, the right rear side of the observer is set as rear, the left rear side of the observer is set as left, the right front side of the observer is set as right, the top of the observer is set as top, and the bottom of the observer is set as bottom. It should be noted that the terms "front end", "rear end", "left side", "right side", "middle", "top", "bottom" and so on in the text indicate the direction or position relationship based on the direction or position relationship set in the drawings, which is only for the convenience of clearly describing the present invention, and does not indicate or imply that the structure or component referred to must have a specific direction or be constructed in a specific direction. Therefore, it cannot be understood as a limitation of the present invention. In addition, the terms "first", "second", "third", and "fourth" are only used for the purpose of clarifying or simplifying the description, and cannot be understood as indicating or implying relative importance or quantity.

[0019] See also Figure 1 The utility model provides a 10kV medium voltage fire-resistant and flame-retardant cable, including a cable core and an outer sheath wrapped around the outer layer of the cable core. The cable core includes a plurality of wire cores and a filler 9. The structure of the wire core is, from the inside to the outside, a conductor 1, a shielding layer 2, an insulating layer 3, an insulating shielding layer 4, a first wrapping tape 5, a metal shielding layer 6, and a copper tape 7; the structure of the outer sheath includes two metal layers.

[0020] Specifically, the structure of the outer sheath from inside to outside is the third wrapping tape 10, the fourth wrapping tape 11, the waterproof layer 12, the first metal layer 13, the oxygen barrier layer 14, the second metal layer 15, the fireproof layer 16, and the outer protective layer 17.

[0021] Specifically, the cable core further includes a second wrapping tape 8. The number of the cores is 3, and the 3 cores are symmetrically distributed in a triangular shape. The second wrapping tape 8 wraps and fixes the positions of the cores relative to each other.

[0022] Specifically, the conductor 1 is a Class 2 compressed round copper conductor; the shielding layer 2 is a semi-conductive rubber inner shielding layer 2; the insulating layer 3 is an EPDM insulating layer; and the insulating shielding layer 4 is a semi-conductive rubber outer shielding layer.

[0023] The conductor 1 uses the second type of compact round copper conductor. Using the second type of compact round copper conductor has the following advantages:

[0024] 1. Improve electrical performance: After being compacted, the surface of the conductor is smooth, round and free of burrs, which can make the electric field on the conductor surface evenly distributed and enhance the electrical insulation performance of the cable.

[0025] 2. Increase the filling factor: It can reduce the conductor diameter, improve the conductor filling factor, save materials to a certain extent and reduce costs.

[0026] 3. Improve stability: Make the connection between conductors tighter, reduce the contact resistance, and improve the stability and reliability of cable operation.

[0027] 4. Facilitate laying and installation: Compared with conductors of other shapes, the round compacted conductor is more convenient for laying and installation. The shielding layer 2 is made of extruded semi-conductive rubber inner shielding material, which has the following advantages:

[0028] 1. Evenly distribute the electric field: It helps to reduce the phenomenon of electric field concentration, make the electric field more evenly distributed on the conductor surface, thereby reducing the risk of partial discharge, and improving the insulation performance and service life of the cable.

[0029] 2. Reduce corona discharge: It can effectively suppress the generation of corona. Corona discharge will cause energy loss, electromagnetic interference and damage to the insulating material. The conductor shielding can reduce this adverse effect. Improve heat dissipation:

[0030] Good conductor shielding helps heat transfer from the conductor to the insulation layer, improves the heat dissipation effect of the cable, and ensures the stability of the cable during operation.

[0031] 3. Enhance mechanical protection: Provide a certain degree of mechanical protection for the conductor, reducing the physical damage that may be suffered during cable installation and operation.

[0032] 4. Improve the stability of electrical performance: Ensure that the electrical performance of the cable remains relatively stable under different working conditions and environmental conditions, and reduce the performance fluctuations caused by external factors.

[0033] The insulating layer 3 is made of extruded ethylene propylene rubber insulation, which has the following advantages:

[0034] 1. Excellent electrical insulation performance: It has a high dielectric strength and volume resistivity, and can effectively prevent current leakage, ensuring the safe and stable operation of the cable.

[0035] 2. Good heat resistance performance: It can maintain stable insulation performance in a relatively high temperature environment, adapting to the heat generation situation that may occur during the operation of medium-voltage cables. Excellent aging resistance:

[0036] 3. Good antioxidant and anti-ultraviolet capabilities; the performance degradation is relatively slow after long-term use, extending the service life of the cable.

[0037] 4. Soft and elastic: Facilitates the installation and bending of the cable, reducing the possible insulation damage during installation.

[0038] 5. Strong chemical corrosion resistance: Can resist the erosion of a variety of chemical substances and adapt to different laying environments.

[0039] 6. Good water tightness: Effectively prevents the penetration of moisture, reducing the risk of insulation performance degradation caused by moisture intrusion.

[0040] The insulation shielding layer 4 uses a semi-conductive rubber outer shielding material, which has the following advantages:

[0041] 1. Improves the electric field distribution: Makes the electric field more evenly distributed in the insulation layer, reduces electric field concentration, and lowers the possibility of partial discharge, thereby improving the insulation reliability and service life of the cable.

[0042] 2. Eliminates the interface effect: Reduces the interface charge accumulation between the conductor and the insulation layer, lowers the electric field distortion at the interface, and helps maintain stable electrical performance.

[0043] 3. Prevents the aging of electrical tree: Can inhibit the initiation and growth of electrical tree. Electrical tree is one of the important factors leading to insulation aging and breakdown, and the insulation shielding can effectively slow down this process.

[0044] 4. Improves the heat dissipation effect: Helps the heat transfer from the insulation layer to the outside, avoids local overheating, and ensures the temperature stability of the cable during operation.

[0045] 5. Enhances the mechanical properties: Provides certain mechanical protection for the insulation layer, reducing the damage to the insulation layer under the influence of installation, operation, and external environment.

[0046] 6. Improves the moisture resistance of the cable: Prevents moisture from penetrating along the insulation layer and maintains the stability of the insulation performance.

[0047] 7. Facilitates construction and installation: Reduces the damage to the insulation layer caused by friction. The semi-conductive rubber has certain flexibility and elasticity, making the cable more convenient during installation and laying.

[0048] Specifically, the first tape 5 is a water-blocking tape, and two layers of water-blocking tapes are overlapped and mechanically wound, with the overlap rate of each layer being 15%-25%; the metal shielding layer 6 is a copper wire shielding layer, and the copper wire shielding layer is loosely wound with 0.85mm soft round copper wires; the copper tape 7 has a reverse winding structure.

[0049] The first wrapping tape 5 is a water-blocking tape, which is mechanically wrapped with 2 layers of water-blocking tapes overlapping. The overlapping rate of each layer is 15%-25%, and it has the following advantages:

[0050] 1. Water blocking and moisture proofing: It can effectively prevent moisture from penetrating along the longitudinal and radial directions of the cable, avoiding problems such as moisture entering the cable interior and causing a decline in insulation performance and corrosion of the conductor, thus ensuring the normal operation of the cable in a humid environment or underwater environment.

[0051] 2. Enhancing longitudinal water-blocking performance: Even when the cable sheath is damaged, the water-blocking tape can, to a certain extent, prevent moisture from spreading along the length direction of the cable and reduce the scope of faults.

[0052] 3. Buffer protection: It provides a certain degree of buffer protection for the insulation shielding layer, reducing the direct impact of external mechanical stress on the insulation structure.

[0053] 4. Improving the reliability and stability of the cable: Reducing the risk of faults caused by moisture intrusion, extending the service life of the cable, and ensuring the stable operation of medium-voltage cables in various complex environments.

[0054] The metal shielding layer 6 is a copper wire shielding layer. The outer layer of the water-blocking tape is sparsely wound and shielded with 0.85mm soft round copper wire, and it has the following advantages:

[0055] 1. Good shielding effect: The copper wire shielding can effectively confine the electric field inside the cable, reducing the interference of external electromagnetic fields on the cable signal transmission, and at the same time reducing the impact of the electromagnetic field generated by the cable itself on the outside.

[0056] Its shielding effect is better than some other shielding methods, and the continuity is relatively reliable.

[0057] 2. Better heat dissipation performance: Compared with copper tape shielding, the current flowing path of copper wire shielding is shorter, and the generated heat is relatively less, which is beneficial to the heat dissipation of the cable.

[0058] 3. Better flexibility: The copper wire is relatively soft, making the cable easier to bend and install to a certain extent, and it can adapt to some occasions where the cable needs to be bent.

[0059] The copper tape 7 has a reverse lashing structure. A layer of copper tape is used to tightly lash in the reverse direction outside the copper wire shielding layer, and it has the following advantages: 1. Enhancing the shielding effect: The combination of the copper tape and the copper wire shielding forms a more rigorous electromagnetic shielding structure, further improving the shielding ability against external electromagnetic fields and ensuring the accuracy and stability of the cable transmission signal.

[0060] 2. Mechanical protection: It provides additional mechanical protection for the internal copper wire shielding and insulation structure, reducing the possible mechanical damage during cable laying and operation.

[0061] 3. Moisture and water resistance: Enhance the moisture and water resistance of the cable, prevent moisture and humidity from penetrating longitudinally along the cable, and protect the insulation performance of the cable.

[0062] 4. Electric field homogenization: Help to distribute the electric field more evenly, reduce the possibility of electric field concentration and partial discharge, and improve the electrical performance and service life of the cable.

[0063] 5. Fixing and stabilizing structure: Make the internal shielding layer and insulation structure more stable, and reduce the structural deformation and displacement caused by cable bending, stretching and other actions.

[0064] Specifically, the second tape 8 is mechanically overlapped and wound with 2 layers of low-smoke, halogen-free and high flame-retardant tapes, and the overlap rate of each layer is 20%-30%; the filler 9 is a flame-retardant high-temperature filling rope.

[0065] The second tape 8 is mechanically overlapped and wound with 2 layers of low-smoke, halogen-free and high flame-retardant tapes, and the overlap rate of each layer is controlled at 20%-30%, which has the following advantages:

[0066] 1. Flame retardancy and fire prevention: When the cable encounters a fire, the flame-retardant tape can delay the spread speed of the flame, reduce the spread of the fire, and reduce the losses caused by the fire.

[0067] 2. Preventing the spread of combustion: It can effectively cut off the spread of the flame between cable bundles, prevent the fire from spreading from one cable to other cables, and thus limit the scale of the fire.

[0068] 3. Reducing smoke and toxic gas emissions: Help to reduce the amount of smoke and toxic gases generated during combustion, and create more favorable conditions for personnel evacuation and fire fighting and rescue.

[0069] 4. Improving the safety of the cable: Enhance the reliability and safety of medium-voltage cables in a fire environment, and ensure the continuity of power supply and the safety of personnel's lives and property.

[0070] 5. Protecting the cable structure: To a certain extent, it plays a role in protecting the internal cable core wires and reducing the direct damage of the fire to the cable structure.

[0071] The space between the wire cores is filled with a flame-retardant high-temperature filling rope, taking the roundness of the cable core as the standard, which has the following advantages: 1. Flame retardant effect: The flame-retardant high-temperature filling rope itself has certain flame retardant performance, which can prevent the spread of the flame to a certain extent and improve the fire safety of the cable.

[0072] 2. Supporting and rounding effect: The flame-retardant high-temperature filling rope can play a role in supporting the inner protective layer, making the cable as a whole maintain a circular or quasi-circular structure, and ensuring the appearance and internal structure stability of the cable.

[0073] 3. Tensile and torsional resistance: It can improve the tensile strength and torsional resistance of the cable, reducing deformation and damage of the cable when it is stretched or twisted during use.

[0074] 4. Buffer protection: Provide buffering for the internal structure of the cable, reducing the direct impact of external mechanical stress on the cable.

[0075] Specifically, the third wrapping tape 10 is a double-sided water-blocking tape, with 2 layers of water-blocking tapes overlapping and mechanically wrapped, and the overlapping rate of each layer is 15%-25%; the fourth wrapping tape 11 is an aluminum-plastic tape, which is longitudinally wrapped, and the overlapping rate is 10%-20%.

[0076] The third wrapping tape 10 is a double-sided water-blocking tape, which is mechanically wrapped with 2 layers of water-blocking tapes overlapping, and the overlapping rate of each layer is between 15% and 25%. It has the following advantages:

[0077] 1. Further enhance the water-blocking performance: The double-sided water-blocking tape can more effectively prevent moisture from invading the cable from all directions, providing all-round waterproof protection.

[0078] 2. Improve the longitudinal water-blocking ability: Even if the cable sheath is partially damaged, it can prevent moisture from penetrating longitudinally along the cable in a relatively long cable section, reducing the possibility of insulation performance degradation and faults caused by moisture intrusion.

[0079] 3. Enhance the sealing of the cable: Further seal the internal structure of the cable, prevent moisture, water vapor, etc. from entering, and maintain a dry environment inside the cable.

[0080] 4. Protect the cable structure: Provide additional protection for the internal wrapping tape and cable core, reducing the influence of external environmental factors on them.

[0081] 5. Prolong the service life of the cable: By preventing the intrusion of moisture, the aging speed of the cable insulation material is reduced.

[0082] Thus, the service life and reliability of the cable are prolonged.

[0083] The fourth wrapping tape 11 is an aluminum-plastic tape. A layer of aluminum-plastic tape is longitudinally wrapped outside the water-blocking tape, and the overlapping rate is between 10% and 20%. It has the following advantages:

[0084] 1. Enhance the radial water-blocking effect: The water permeability of metallic aluminum is almost zero. The longitudinally wrapped aluminum-plastic composite tape and its outer polyethylene sheath jointly form an excellent waterproof and moisture-proof material, which can effectively prevent moisture from radially invading the cable interior, improving the reliability and stability of the cable in humid or underwater environments.

[0085] 2. Shielding effect: It plays a role similar to that of the traditional copper tape shielding structure, shielding the electromagnetic field generated when the cable is energized within the insulated conductor core to reduce electromagnetic interference to the outside world. At the same time, it can also safely introduce the fault current within the designed range generated by the system into the grounding system to protect the safe operation of the system.

[0086] 3. Cost reduction: The content of aluminum elements in the earth's crust is relatively abundant, and the price of aluminum is lower than that of copper, and the density is also smaller. Adopting the longitudinal wrapping aluminum-plastic composite tape shielding structure can reduce the use of non-ferrous metals and lower the production cost of the cable.

[0087] As a preferred embodiment of the present invention, the waterproof layer 12 is a layer of flame-retardant polyethylene layer. The waterproof layer 12 is a tooth sleeve structure, and the teeth protrude from the inner layer to the outer layer. The inner layer of the waterproof layer 12 is a smooth structure; the first metal layer 13 is a corrugated aluminum sheath, welded to the outer layer of the waterproof layer 12. Specifically, the oxygen barrier layer 14 is a layer of low-smoke and halogen-free polyethylene layer. The oxygen barrier layer 14 is a tooth sleeve structure, and the teeth protrude from the inner layer to the outer layer. The inner layer of the oxygen barrier layer 14 is a smooth structure; the second metal layer 15 is a corrugated aluminum sheath, welded to the outer layer of the oxygen barrier layer 14; the space between the oxygen barrier layer 14 and the front and rear metal layers is a water channel, and the water channel can be provided with flowing cooling water.

[0088] The first metal layer 13 is a corrugated aluminum sheath, and an aluminum alloy material is welded outside the waterproof layer 12, which has the following advantages:

[0089] 1. Radial water blocking: The corrugated aluminum sheath has good impermeability, which can effectively prevent moisture from radially invading the cable interior, play a role in radial water blocking, protect the insulation performance of the cable, and ensure the stable operation of the cable in a humid or underwater environment.

[0090] 2. Mechanical protection: It can enhance the mechanical strength of the cable, provide additional protection for the internal structure, and enable it to withstand certain external pressures, tensile forces, and torsional mechanical stresses.

[0091] 3. Shielding effect: Welding the corrugated aluminum sheath can achieve a certain electromagnetic shielding effect, reduce the interference of the electromagnetic field inside the cable to the outside world, and at the same time reduce the influence of the external electromagnetic field on the cable signal transmission.

[0092] 4. Anti-corrosion: Although aluminum itself is relatively easy to corrode, in some cases, the combination of the waterproof layer 12 and the corrugated aluminum sheath can delay the corrosion process to a certain extent and protect the internal metal structure of the cable.

[0093] Extrude a layer of low-smoke and halogen-free polyethylene material as the oxygen barrier layer 14 and adopt a tooth sleeve design, which has the following advantages:

[0094] 1. The functions of the oxygen barrier layer with a tooth sleeve design: Strengthen the oxygen barrier effect: The tooth sleeves are tightly meshed, reducing the channels and possibilities of oxygen penetration and enhancing the barrier performance of the oxygen barrier layer. Increase connection stability: It increases the contact area and friction between the oxygen barrier layer and the corrugated aluminum sheath, making their connection more secure and less likely to separate due to water flow impact or external interference. Adapt to structural changes: Under temperature changes and water flow effects, the structure may deform. The tooth sleeve design can provide a certain degree of elasticity and adaptability to maintain a good combination between the oxygen barrier layer and the corrugated aluminum sheath. Evenly disperse pressure: It helps to evenly distribute the external pressure across the entire contact surface, reducing damage caused by excessive local pressure and improving the compressive capacity of the structure.

[0095] 2. Flame retardant function: This material itself has a certain flame retardant property, which can, to a certain extent, prevent the spread of fire and reduce the hazards of fire.

[0096] 3. Oxygen barrier effect: Effectively isolate oxygen, slow down the oxidation reaction during combustion, and thus reduce the combustion speed and fire intensity.

[0097] 4. Low smoke emission: It produces less smoke during combustion, which is beneficial to improving visibility during a fire and creating better conditions for personnel evacuation and fire fighting and rescue.

[0098] 5. Halogen-free and environmentally friendly: It does not contain halogens and will not release toxic hydrogen halide gas during combustion, causing less harm to the environment and human health.

[0099] 6. Protect the internal structure of the cable: Prevent the internal conductors, insulation layers, etc. from being directly damaged by high temperature and fire, and extend the normal working time of the cable during a fire.

[0100] 7. Meet safety standards: Meet the strict requirements of many building and electrical installations for fire prevention, environmental protection, etc.,

[0101] Improve the safety and reliability of cable use.

[0102] The second metal layer 15 is a corrugated aluminum sheath. An aluminum alloy material is welded outside the oxygen barrier layer 14, and flowing cooling water is added between the oxygen barrier layer 14 and the front and rear corrugated aluminum sheaths. The main effects are to enhance the heat dissipation capacity of the cable and have a significant effect on flame retardancy and fire prevention. During the operation of the cable, heat is generated. If the heat cannot be dissipated in time, it may affect the performance and lifespan of the cable and even lead to failures. The flowing cooling water can effectively carry away the heat conducted from the corrugated aluminum sheath, the oxygen barrier layer 14, and the waterproof layer 12, helping the cable dissipate heat and maintaining its normal operating temperature, thereby improving the current-carrying capacity of the cable and enabling it to operate stably at a higher current. At the same time, welding a corrugated aluminum sheath outside the oxygen barrier layer 14 again can enhance the mechanical strength. The welded corrugated aluminum sheath can provide additional mechanical protection for the cable, enabling it to better withstand external pressures, tensile forces, twists, and other mechanical stresses, and reducing damage to the cable during use, installation, or operation. This setting has the following advantages:

[0103] 1. Moisture and water resistance: Further improve the moisture and water resistance of the cable. Although the oxygen barrier layer itself may have a certain moisture-proof effect, the corrugated aluminum sheath can serve as a more reliable barrier to prevent the intrusion of moisture and protect the internal insulation and other structures.

[0104] 2. Electromagnetic shielding: Welding the corrugated aluminum sheath helps enhance the electromagnetic shielding effect of the cable, reducing interference from external electromagnetic fields on cable signal transmission and also reducing the impact of the internal electromagnetic field of the cable on the outside world.

[0105] 3. Auxiliary fire protection: Although the oxygen barrier layer already has a certain fire protection performance, the corrugated aluminum sheath can play a certain auxiliary fire protection role in a high-temperature environment. It can delay the transfer of heat to the interior, reduce the impact of fire on the cable, and help maintain the integrity and electrical performance of the cable during a fire.

[0106] 4. Anti-corrosion: Although the corrugated aluminum sheath itself is not completely corrosion-proof, it can resist chemical substances and corrosive factors in the external environment to a certain extent and protect the internal structure of the cable.

[0107] Specifically, the fire protection layer 16 is a layer of polyamide; the outer protection layer 17 is a layer of silicone rubber.

[0108] Extruding a layer of polyamide (PA) material as the fire protection layer 16 has the following advantages:

[0109] 1. Good mechanical properties: Polyamide is a typical hard and tough polymer with high tensile strength, compressive strength, impact strength, and wear resistance. Its comprehensive mechanical properties are superior to those of general plastics, which can enhance the cable's resistance to tensile, bending, and impact forces and protect the internal structure of the cable from mechanical damage.

[0110] 2. Good heat resistance: It has a relatively high melting temperature and a narrow melting temperature range, with an obvious melting point, mostly around 200 °C, and can adapt to the relatively high working temperature environment that medium-voltage cables may face.

[0111] 3. Strong chemical corrosion resistance: It is stable to the action of most chemical reagents, especially has strong resistance to oils such as gasoline and lubricating oil, and is also relatively stable to the action of alkalis and most salts.

[0112] 4. Self-extinguishing property: Even if it burns, the flame propagation speed is extremely slow.

[0113] 5. Good wear resistance: It has a low friction coefficient. If fillers such as molybdenum disulfide and graphite are added, its wear resistance can be further improved, which helps to reduce the wear of the cable during use.

[0114] 6. Good processability: It has a low melt viscosity and high fluidity, which is convenient for processing and forming.

[0115] 7. Waterproof and moisture-proof: It can prevent moisture from invading the cable interior to a certain extent and protect the insulation performance of the cable.

[0116] Extruding a layer of silicone rubber as the outer protective layer 17 has the following advantages:

[0117] 1. Excellent heat resistance: It can maintain good performance in a relatively wide temperature range, adapt to high-temperature environments, and ensure the normal operation of the cable under high-temperature conditions.

[0118] 2. Good cold resistance: It still maintains flexibility in low-temperature environments and is not easily embrittled, suitable for use in cold regions.

[0119] 3. Excellent electrical insulation performance: It effectively prevents current leakage and ensures the electrical safety performance of the cable.

[0120] 4. Strong weather resistance: It can resist the erosion of environmental factors such as ultraviolet rays, ozone, acids and alkalis, and still maintain good performance after long-term exposure to outdoor environments.

[0121] 5. Good flexibility: It is convenient for the installation and bending of the cable, reducing damage during the installation process.

[0122] 6. Flame retardant property: It has a certain flame retardant ability, which helps to improve the safety of the cable in case of fire.

[0123] 7. Good anti-aging performance: It has a long service life, reducing the frequency of cable maintenance and replacement.

[0124] 8. Waterproof and moisture-proof performance: It effectively prevents the intrusion of moisture and dampness and protects the internal structure of the cable.

[0125] The utility model relates to a halogen-free low-smoke flame-retardant class A medium-voltage fire-resistant cable with self-cooling function. It adopts a secondary voltage transformation scheme. On the basis of solving the power supply problem of the entire fire protection loop, it can also meet the corresponding fire protection requirements at the same time. In case of a fire, it can maintain the normal operation of the power system for a certain period of time, winning more precious time for personnel evacuation and fire rescue.

[0126] The beneficial effects of the utility model are as follows:

[0127] The design of welding corrugated aluminum sheaths is adopted outside the waterproof layer and the oxygen isolation layer respectively. Both the waterproof layer and the oxygen isolation layer adopt tooth sleeve designs. The tooth sleeve of the waterproof layer can enhance the sealing and waterproof performance, improve the bonding strength, adapt to deformation and displacement. The tooth sleeve design can provide a certain degree of flexibility and adaptability, and evenly distribute the pressure. The oxygen isolation layer with a tooth sleeve strengthens the oxygen isolation effect, enhances the barrier performance of the oxygen isolation layer, increases the connection stability, and adapts to structural changes. The tooth sleeve design can provide a certain degree of elasticity and adaptability, maintaining a good combination between the oxygen isolation layer and the corrugated aluminum sheath. At the same time, flowing cooling water is added between the two layers of corrugated aluminum sheaths before and after the oxygen isolation layer. And the oxygen isolation layer adopts a tooth sleeve design, which further increases the flow rate of the cooling water, enhances the heat dissipation capacity of the cable and has a significant effect on flame retardancy and fire prevention. During the operation of the cable, heat will be generated. If the heat cannot be dissipated in time, it may affect the performance and lifespan of the cable, and even cause failures. The flowing cooling water can effectively take away the heat conducted from the corrugated aluminum sheath, the oxygen isolation layer and the waterproof layer, help the cable dissipate heat, maintain its normal working temperature, thereby improving the current-carrying capacity of the cable and enabling it to operate stably at a higher current.

[0128] At the same time, this design has a significant effect on flame retardancy and fire prevention, which is mainly reflected in the following aspects.

[0129] 1. Rapid cooling: When a fire occurs around the cable or the cable itself generates abnormal heat, the flowing cooling water can quickly absorb heat, reduce the temperature of the cable, delay the time for the cable to reach the combustion point, thereby enhancing the flame retardant effect.

[0130] 2. Prevent the spread of fire: By reducing the temperature of the cable and reducing heat transfer, it can effectively prevent the fire from spreading along the cable and limit the scope of the fire.

[0131] Maintain structural integrity: In a high-temperature environment, the cooling water can keep the structure of the cable at a relatively low temperature, reduce material deformation and damage caused by high temperature, help maintain the structural integrity of the cable, and ensure its normal operation within a certain period of time.

[0132] 3. Reduce the generation of smoke and toxic gases: Reducing the temperature helps to reduce the amount of smoke and toxic gases generated when the cable burns, improve the environment at the fire scene, and provide more favorable conditions for personnel evacuation and rescue.

[0133] 4. Enhance the fire resistance time: The flowing cooling water can provide continuous cooling protection for the cable, extend the cable's tolerance time in a fire, and gain more precious time for taking fire extinguishing measures and personnel evacuation.

[0134] The above is the preferred embodiment of the present utility model. It should be noted that for those of ordinary skill in the art of this technology, without departing from the principle of the present utility model, several improvements and refinements can be made, and these improvements and refinements are also regarded as the protection scope of the present utility model.

Claims

1. A 10kV medium-voltage fire-resistant and flame-retardant cable, comprising a cable core and an outer sheath wrapped around the outer layer of the cable core, characterized in that: The cable core includes a plurality of cores and fillers. The structure of the core from the inside to the outside is successively a conductor, a shielding layer, an insulating layer, an insulation shielding layer, a first tape, a metal shielding layer, and a copper tape. The structure of the outer sheath includes two metal layers.

2. The 10 kV medium voltage fire-resistant and flame-retardant cable according to claim 1, wherein: The structure of the outer sheath from the inside to the outside is successively a third tape, a fourth tape, a waterproof layer, a first metal layer, an oxygen barrier layer, a second metal layer, a fireproof layer, and an outer protective layer.

3. The 10 kV medium-voltage fire-resistant and flame-retardant cable according to claim 2, wherein: The cable core further includes a second tape. The number of cores is 3, and the 3 cores are symmetrically distributed in a triangular shape. The second tape wraps and fixes the positions of the cores relative to each other.

4. The 10kV medium voltage fire-resistant and flame-retardant cable according to claim 3, wherein: The conductor is a Class 2 compact round copper conductor; the shielding layer is a semi-conductive rubber inner shielding layer; the insulating layer is an ethylene propylene rubber insulating layer; the insulation shielding layer is a semi-conductive rubber outer shielding layer.

5. The 10 kV medium voltage fire-resistant and flame-retardant cable according to claim 4, characterized in that: The first tape is a water-blocking tape. 2 layers of the water-blocking tapes are overlapped and mechanically lapped. The overlapping rate of each layer is between 15% and 25%. The metal shielding layer is a copper wire shielding layer, and the copper wire shielding layer is loosely wound and shielded with 0.85 mm soft round copper wires. The copper tape has a reverse lashing structure.

6. A 10 kV medium voltage fire-resistant and flame-retardant cable according to any one of claims 3 to 5, characterized in that: The second tape is 2 layers of low-smoke, halogen-free, high-fire-retardant tapes mechanically overlapped and wound. The overlapping rate of each layer is between 20% and 30%. The filler is a fire-retardant high-temperature filling rope.

7. The 10 kV medium voltage fire-resistant and flame-retardant cable according to claim 6, characterized in that: The third tape is a double-sided water-blocking tape. 2 layers of the water-blocking tapes are overlapped and mechanically lapped. The overlapping rate of each layer is between 15% and 25%. The fourth tape is an aluminum-plastic tape, and the aluminum-plastic tape is longitudinally wrapped with an overlapping rate between 10% and 20%.

8. The 10kV medium voltage fire-resistant and flame-retardant cable according to claim 2 or 3 or 4 or 5 or 7, characterized in that: The waterproof layer is a layer of flame-retardant polyethylene layer. The waterproof layer has a tooth sleeve structure, and the teeth protrude from the inner layer to the outer layer. The inner layer of the waterproof layer is a smooth structure. The first metal layer is a corrugated aluminum sheath, welded to the outer layer of the waterproof layer.

9. The 10 kV medium voltage fire-resistant and flame-retardant cable according to claim 8, characterized in that: The oxygen barrier layer is a layer of low-smoke, halogen-free polyethylene layer. The oxygen barrier layer has a tooth sleeve structure, and the teeth protrude from the inner layer to the outer layer. The inner layer of the oxygen barrier layer is a smooth structure. The second metal layer is a corrugated aluminum sheath, welded to the outer layer of the oxygen barrier layer. The space between the oxygen barrier layer and the two metal layers before and after is a water channel, and flowing cooling water can be arranged in the water channel.

10. The 10 kV medium voltage fire-resistant and flame-retardant cable according to claim 2 or 3 or 4 or 5 or 7 or 9, characterized in that: The fireproof layer is a layer of polyamide layer; the outer protective layer is a layer of silicone rubber layer.

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