Flame-retardant impact-resistant composite low-voltage power cable

Abstract

The invention discloses a flame-retardant impact-resistant composite low-voltage power cable which comprises a cable core, a low-smoke halogen-free wrapping layer wrapping the cable core, an oxygen barrier layer and an outer sheath. The oxygen barrier layer and the outer sheath are arranged outside the low-smoke halogen-free wrapping layer from inside to outside. The cable core is formed by twisting a plurality of power line cores and a plurality of signal line cores, and the power line cores and the signal line cores are symmetrically twisted in a triangle shape. A filling rope is filled in a twisting gap of the cable core; the oxygen barrier layer is extruded outside the low-smoke halogen-free wrapping layer, and the oxygen barrier layer is made of high-flame-retardant polystyrene; and the outer sheath is extruded outside the oxygen barrier layer, and the material of the outer sheath is impact-resistant and high-temperature-resistant polystyrene. The cable has excellent flame retardation, impact resistance and safety performance, and also has the advantages of space saving, labor cost reduction, good high temperature resistance, good flexibility, high tensile strength, stable signal transmission, good insulation performance, environmental protection and good environmental resistance.

Description

Technical Field

[0001] The invention relates to the field of power cables, in particular to a flame-retardant and impact-resistant composite low-voltage power cable. Background Art

[0002] In the construction of power systems, long-distance transmission relies on overhead power networks, the middle part of power transmission and distribution relies on medium-voltage power cables, and power access relies on low-voltage power cables. Low-voltage power cables are suitable for fixed laying on AC 50Hz, rated voltage 3kv and below transmission and distribution lines for transmitting electric energy. They are generally buried in the soil or laid indoors, in trenches, and tunnels. Since low-voltage power cables are generally used in densely populated residential and commercial buildings. Specifically, low-voltage power cables are mainly used for indoor wiring in residential buildings to connect various household appliances and lighting equipment to ensure the safety of residents' electricity use. These cables need to have good safety performance, flame retardancy and durability to adapt to frequent use and high load requirements in densely populated environments. In commercial buildings, low-voltage power cables also play a key role. They are used to connect office facilities, lighting systems and various commercial equipment to ensure the smooth progress of commercial activities. The cable layout of commercial buildings is usually more complex, requiring these cables to have higher transmission efficiency and safety. In addition, densely populated residential and commercial buildings also have certain requirements for the environmental adaptability of cables, such as being able to withstand certain mechanical pressures, etc., to ensure the long-term stable operation of the cables. At the same time, since low-voltage power cables are buried in the soil or laid indoors, in trenches, and tunnels, during construction or use, when low-voltage power cables are accidentally impacted or vibrated, they need to maintain structural integrity and electrical performance stability. Therefore, low-voltage cables are also required to have excellent impact resistance. In summary, low-voltage power cables need to have safety performance, flame retardancy, durability, and impact resistance.

[0003] At the same time, low-voltage power cables are mostly used for urban power transmission, where land resources are relatively scarce and expensive. For power and communication lines, two lines are generally laid in parallel without interfering with each other: that is, a power transmission channel is built, and after the cable is laid and installed, the communication line channel is constructed, and the optical cable is laid and installed. In order to overcome the above contradictions, cables with thicker diameters are often used, which increases the production cost of the cables. This wastes both land resources and manpower and material resources. Summary of the invention

[0004] The purpose of the present invention is to provide a flame retardant and impact resistant composite low-voltage power cable with good flame retardancy, excellent impact resistance, good insulation performance and high safety performance in view of the deficiencies in the prior art.

[0005] The technical purpose of the present invention is achieved by the following technical solutions: A flame-retardant and impact-resistant composite low-voltage power cable comprises a cable core, a low-smoke halogen-free sheath wrapped around the cable core, and an oxygen-isolating layer and an outer sheath arranged outside the low-smoke halogen-free sheath from the inside to the outside; the cable core is formed by twisting a plurality of power cores and a plurality of signal cores, and the power cores and the signal cores are symmetrically twisted in a herringbone shape; the twisted gap of the cable core is filled with a filling rope; the oxygen-isolating layer is extruded outside the low-smoke halogen-free sheath, and the material of the oxygen-isolating layer is highly flame-retardant polystyrene; the outer sheath is extruded outside the oxygen-isolating layer, and the material of the outer sheath is impact-resistant and high-temperature-resistant polystyrene.

[0006] Preferably, the oxygen-isolating layer contains a temperature-sensitive optical fiber.

[0007] Preferably, the power cord core comprises a first conductor and a first insulating layer arranged outside the first conductor, and a mica tape wrapping layer is provided between the first conductor and the first insulating layer.

[0008] Preferably, the first conductor is formed by twisting a number of tinned copper wires; the mica tape wrapping layer is an overlapping wrapping structure of the mica tape outside the first conductor; the first insulating layer is extruded outside the mica tape wrapping layer, and the material of the first insulating layer is flame-retardant cross-linked polyethylene.

[0009] Preferably, the signal line core is composed of a second conductor and a second insulating layer; the second conductor is formed by twisting a plurality of tinned copper wires; the second insulating layer is extruded outside the second conductor, and the material of the second insulating layer is cross-linked polyethylene.

[0010] Preferably, the exterior of the outer sheath is coated with a fire retardant coating.

[0011] Preferably, the filling rope is a flame retardant filling rope.

[0012] Preferably, the material of the low-smoke zero-halogen wrapping layer is a low-smoke zero-halogen flame retardant tape.

[0013] Preferably, the material of the first insulating layer is a cross-linked polyethylene with a temperature resistance of 125° C. and a magnesium hydroxide additive added thereto.

[0014] Preferably, the material of the second insulating layer is a cross-linked polyethylene with a temperature resistance of 125° C. and a magnesium hydroxide additive added thereto.

[0015] Compared with the prior art, the present invention has the following beneficial effects: 1. The present invention comprises a cable core, a low-smoke halogen-free wrapping layer wrapped outside the cable core, and an oxygen-insulating layer and an outer sheath arranged outside the low-smoke halogen-free wrapping layer from the inside to the outside; the cable core is twisted by multiple power cores and multiple signal cores, and the power cores and the signal cores are twisted symmetrically in a herringbone shape; the twisted gap of the cable core is filled with a filling rope; the oxygen-insulating layer is extruded outside the low-smoke halogen-free wrapping layer, and the material of the oxygen-insulating layer is highly flame-retardant polystyrene; the outer sheath is extruded outside the oxygen-insulating layer, and the material of the outer sheath is impact-resistant and high-temperature-resistant polystyrene. The present invention has excellent flame-retardant performance, impact resistance and safety performance, and at the same time, it also has the advantages of saving space, reducing labor costs, good high-temperature resistance, good flexibility, high tensile strength, stable signal transmission, good insulation performance, environmental protection, and good environmental resistance.

[0016] 2. The oxygen-insulating layer of the present invention contains temperature-sensitive optical fibers. Four temperature-sensitive optical fibers are evenly arranged in the oxygen-insulating layer along the circumferential direction. By arranging temperature-sensitive optical fibers, the temperature change of the cable can be monitored in real time, so that the existing safety hazards can be discovered and handled in time. The adoption of this technical measure can effectively enhance the safety performance of the cable.

[0017] 3. The outer sheath of the present invention is coated with a fire retardant coating on the outside. For example, a layer of cable fire retardant coating is applied on the outer sheath, such as YDAH-102 cable fire retardant coating. YDAH-102 cable fire retardant coating is a new type of fire retardant coating. When the coating is exposed to fire, it can generate a uniform and dense sponge-like foam insulation layer, which effectively inhibits and blocks the spread and spread of flames. It has the characteristics of environmental protection, non-toxic and tasteless, thin coating, strong adhesion, good flexibility, etc., and has good insulation and anti-corrosion functions. The above structure can further improve the flame retardant performance of the cable, reduce the damage to the cable caused by external environmental factors, and effectively improve the safety performance.

[0018] 4. The material of the first insulating layer and the second insulating layer of the present invention is a magnesium hydroxide additive added to a temperature-resistant 125°C cross-linked polyethylene. The magnesium hydroxide additive is added to the 125°C cross-linked polyethylene to improve its flame retardant properties and reduce smoke generation. The above structure can effectively improve the flame retardant properties of the entire cable, while also reducing smoke hazards, making the cable highly safe and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the structure of the present invention; Figure numerals: 1—power line core; 11—first conductor; 12—mica tape sheath; 13—first insulation layer; 2—signal line core; 21—second conductor; 21—second insulation layer; 3—filling rope; 4—low-smoke halogen-free sheath; 5—oxygen insulation layer; 51—temperature-sensitive optical fiber; 6—outer sheath; 7—fire retardant coating. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0021] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] It should be noted that similar reference numerals and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further defined and explained in the subsequent drawings. In addition, the terms "first", "second", etc. are only used to distinguish the description and cannot be understood as indicating or implying relative importance.

[0023] like Figure 1 As shown, a flame-retardant and impact-resistant composite low-voltage power cable comprises a cable core, a low-smoke halogen-free sheath 4 wrapped around the cable core, and an oxygen-insulating layer 5 and an outer sheath 6 arranged outside the low-smoke halogen-free sheath 4 from the inside to the outside; the cable core is formed by twisting a plurality of power cores 1 and a plurality of signal cores 2, and the power cores 1 and the signal cores 2 are symmetrically twisted in a triangular shape; the twisted gap of the cable core is filled with a filling rope 3; the oxygen-insulating layer 5 is extruded outside the low-smoke halogen-free sheath 4, and the material of the oxygen-insulating layer 5 is highly flame-retardant polystyrene; the outer sheath 6 is extruded outside the oxygen-insulating layer 5, and the material of the outer sheath 6 is impact-resistant and high-temperature-resistant polystyrene. In actual use, the highly flame-retardant polystyrene used in the oxygen-insulating layer 5 not only has excellent flame retardancy, but also has good impact resistance and weather resistance. When burning, its extinguishing time is short, and the residual flame existence time is only 0-23 seconds, which can effectively retard flames. In order to further improve the safety performance, impact resistance and flame retardancy of the cable, the oxygen barrier layer 5 is extruded with an outer sheath 6. The impact-resistant and high-temperature resistant polystyrene used in the outer sheath 6 has both impact resistance and high-temperature resistance, and can maintain stable performance at higher temperatures. At the same time, it also has excellent low-temperature resistance, chemical stability and electrical insulation. In actual use, the impact-resistant and high-temperature resistant polystyrene can be the existing disclosed impact-resistant and high-temperature resistant polystyrene cable material. By adopting the above technical measures, the low-voltage power cable has the functions of power transmission and communication transmission at the same time, and at the same time, has excellent flame retardancy and impact resistance, thereby improving the safety performance of the low-voltage power cable.

[0024] The cable core is composed of three power cores 1 and three signal cores 2 twisted together. The cable core is composed of the power core 1 and the signal core 2, which saves space; during the laying and installation, it can be carried out simultaneously, reducing the labor cost. Specifically, the power core 1 and the signal core 2 are symmetrically twisted in a herringbone shape. The symmetrical twisting of the power core 1 and the signal core 2 in a herringbone shape helps to improve the flexibility and tensile strength of the cable, as well as helps to reduce electromagnetic interference and improve the stability of signal transmission.

[0025] The power cord core 1 includes a first conductor 1 and a first insulating layer 13 arranged outside the first conductor 1, and a mica tape wrapping layer 12 is arranged between the first conductor 1 and the first insulating layer 13. The power cord core 1 is a highly flame-retardant power cord core. The first conductor 1 is a soft copper conductor of the power cord core, and the soft copper conductor of the power cord core is composed of three layers of co-directional twisting. Specifically, the first conductor 1 is a twisted structure of several tinned copper wires with a single wire diameter of 0.1 to 0.5 mm. The first conductor 1 adopts a twisted structure to maintain the high conductivity of the copper wire and meet the requirements of electrical transmission. The tinned layer enhances corrosion resistance and is suitable for humid, acidic and alkaline environments. The multi-strand twisted design makes the power cord core 1 have excellent flexibility and bending fatigue resistance. The material of the mica tape wrapping layer 12 is a mica tape with a thickness of 0.15 mm and a width of 15 to 60 mm. The mica tape is wrapped around the first conductor 1 in an overlapping wrapping structure to form a mica tape wrapping layer 12. Mica tape can usually withstand high temperatures of 750~1000℃, ensuring that it can maintain excellent insulation performance in high temperature environments. At the same time, it also has good environmental performance, does not contain asbestos, and does not produce toxic gases at high temperatures; it also has the characteristics of acid and alkali resistance, corona resistance, radiation resistance, and excellent flame retardant properties. The material of the first insulating layer 13 is flame retardant cross-linked polyethylene, and the extrusion thickness is 0.7~1.8mm. Flame retardant cross-linked polyethylene has excellent environmental resistance, chemical corrosion resistance, creep resistance, electrical properties, insulation performance and temperature resistance. The power cord core 1 using the above structure has excellent flexibility and bending fatigue resistance as well as excellent flame retardant properties and environmental resistance.

[0026] The signal core 2 is composed of a second conductor 21 and a second insulating layer 22. Specifically, the second conductor 21 is a soft copper conductor of the power core 1, and the soft copper conductor of the power core 1 is composed of three layers of co-directional twisting. The second conductor 21 is a twisted structure of several tinned copper wires with a single wire diameter of 0.1 to 0.5 mm; the second insulating layer 22 is extruded outside the second conductor 21, and the material of the second insulating layer 22 is cross-linked polyethylene. Cross-linked polyethylene has excellent chemical corrosion resistance, creep resistance, electrical properties, heat resistance and good insulation properties. The signal core 2 with the above structure has excellent flexibility and bending fatigue resistance, good insulation properties, and excellent flame retardancy and environmental resistance.

[0027] A low-smoke halogen-free wrapping layer 4 is provided outside the cable core. Specifically, the low-smoke halogen-free wrapping layer 4 is made of low-smoke halogen-free flame retardant tape material. Low-smoke halogen-free flame retardant tape is a flame retardant material that produces low smoke and does not contain halogen when burned. The low-smoke halogen-free flame retardant tape has excellent heat resistance, impact resistance and fire resistance, and can reach the UL94 V-0 fire rating. At the same time, its chemical properties are stable and will not release corrosive or acidic gases. By arranging a low-smoke halogen-free wrapping layer 4 made of low-smoke halogen-free flame retardant tape material outside the cable core, the flame retardant performance, heat resistance and impact resistance of the cable can be effectively improved.

[0028] The twisted gap of the cable core is filled with a filling rope 3. In actual use, the filling rope 3 is a flame retardant filling rope 3. The adoption of this technical measure can effectively improve the flame retardant performance and safety performance of the cable.

[0029] An oxygen barrier layer 5 is provided outside the low-smoke halogen-free wrapping layer 4. The oxygen barrier layer 5 is extruded outside the low-smoke halogen-free wrapping layer 4. The material of the oxygen barrier layer 5 is highly flame-retardant polystyrene. The thickness of the oxygen barrier layer 5 is more than 1.6 mm. The highly flame-retardant polystyrene used in the oxygen barrier layer 5 not only has excellent flame retardancy, but also has good impact resistance and weather resistance. The above structure can further improve the flame retardancy of the cable, and also make the cable have good impact resistance and weather resistance.

[0030] The outer sheath 6 is extruded outside the oxygen insulation layer 5, and the material of the outer sheath 6 is impact-resistant and high-temperature resistant polystyrene. Specifically, the outer sheath 6 is made of impact-resistant and high-temperature resistant polystyrene cable material, and the thickness of the outer sheath 6 is more than 1.8 mm. The outer impact-resistant and high-temperature resistant polystyrene has both impact resistance and high temperature resistance, and can maintain stable performance at higher temperatures. At the same time, it also has excellent low-temperature resistance, chemical stability and electrical insulation. The use of the above structure can further improve the high temperature resistance, impact resistance and insulation performance of the cable.

[0031] The oxygen-isolating layer 5 contains a temperature-sensitive optical fiber 51. Specifically, four temperature-sensitive optical fibers 51 are evenly arranged in the oxygen-isolating layer 5 along the circumferential direction. By providing the temperature-sensitive optical fibers 51, the temperature change of the cable can be monitored in real time, so that the existing safety hazards can be discovered and handled in time. The adoption of this technical measure can effectively enhance the safety performance of the cable.

[0032] The outer sheath 6 is coated with a fire retardant coating 7. For example, a layer of cable fire retardant coating is applied to the outer sheath 6, such as YDAH-102 cable fire retardant coating. YDAH-102 cable fire retardant coating is a new type of fire retardant coating. When the coating is exposed to fire, it can generate a uniform and dense sponge-like foam insulation layer, which effectively inhibits and blocks the spread and spread of flames. It has the characteristics of environmental protection, non-toxic and tasteless, thin coating, strong adhesion, good flexibility, etc., and has good insulation and anti-corrosion functions. The above structure can further improve the flame retardant performance of the cable, reduce the damage to the cable caused by external environmental factors, and effectively improve the safety performance.

[0033] Example 2 The other contents of this embodiment are the same as those of Embodiment 1, except that the material of the first insulating layer 13 covering the power cord core 1 and the second insulating layer 22 covering the signal cord core 2 is a magnesium hydroxide additive added to a 125°C temperature-resistant cross-linked polyethylene. The addition of the magnesium hydroxide additive to the 125°C cross-linked polyethylene is mainly to improve its flame retardant properties and reduce smoke generation. Specifically, magnesium hydroxide, as a flame retardant additive, can form a hard carbon layer when the polyethylene material burns, preventing the spread of flames and achieving the purpose of fire prevention. Magnesium hydroxide also has a certain smoke suppression effect, which can reduce the harm of smoke to the human body. The above structure can effectively improve the flame retardant properties of the entire cable, while also reducing the harm of smoke, making the cable highly safe and environmentally friendly.

[0034] The technical solutions provided by the embodiments of the present invention are introduced in detail above. Specific examples are used herein to illustrate the principles and implementation methods of the embodiments of the present invention. The description of the above embodiments is only applicable to help understand the principles of the embodiments of the present invention. At the same time, for those skilled in the art, according to the embodiments of the present invention, there will be changes in the specific implementation methods and application scopes. In summary, the content of this specification should not be understood as limiting the present invention.

Claims

1. A flame retardant and impact resistant composite low-voltage power cable, characterized in that: It comprises a cable core, a low-smoke halogen-free wrapping layer wrapped around the cable core, and an oxygen-isolating layer and an outer sheath arranged outside the low-smoke halogen-free wrapping layer from the inside to the outside; The cable core is formed by twisting a plurality of power line cores and a plurality of signal line cores, and the power line cores and the signal line cores are twisted symmetrically in a herringbone shape; the twisted gaps of the cable core are filled with filling ropes; The oxygen-isolating layer is extruded outside the low-smoke halogen-free wrapping layer, and the material of the oxygen-isolating layer is highly flame-retardant polystyrene; The outer sheath is extruded outside the oxygen-isolating layer, and the material of the outer sheath is impact-resistant and high-temperature-resistant polystyrene.

2. The flame-retardant and impact-resistant composite low-voltage power cable according to claim 1, characterized in that: The oxygen isolation layer contains temperature-sensitive optical fiber.

3. The flame-retardant and impact-resistant composite low-voltage power cable according to claim 1, characterized in that: The power line core comprises a first conductor and a first insulating layer arranged outside the first conductor, and a mica tape wrapping layer is arranged between the first conductor and the first insulating layer.

4. The flame-retardant and impact-resistant composite low-voltage power cable according to claim 3, characterized in that: The first conductor is formed by twisting a plurality of tinned copper wires; The mica tape wrapping layer is an overlapping wrapping structure of the mica tape outside the first conductor; The first insulating layer is extruded outside the mica tape wrapping layer, and the material of the first insulating layer is flame-retardant cross-linked polyethylene.

5. The flame-retardant and impact-resistant composite low-voltage power cable according to claim 1, characterized in that: The signal line core is composed of a second conductor and a second insulating layer; the second conductor is formed by twisting a plurality of tinned copper wires; the second insulating layer is extruded outside the second conductor, and the material of the second insulating layer is cross-linked polyethylene.

6. The flame-retardant and impact-resistant composite low-voltage power cable according to claim 1, characterized in that: The exterior of the outer sheath is coated with a fire retardant coating.

7. The flame-retardant and impact-resistant composite low-voltage power cable according to claim 1, characterized in that: The filling rope is a flame retardant filling rope.

8. The flame-retardant and impact-resistant composite low-voltage power cable according to claim 1, characterized in that: The material of the low-smoke zero-halogen wrapping layer is a low-smoke zero-halogen flame retardant tape.

9. The flame-retardant and impact-resistant composite low-voltage power cable according to claim 3, characterized in that: The material of the first insulating layer is a cross-linked polyethylene with a temperature resistance of 125° C. and a magnesium hydroxide additive added thereto.

10. The flame-retardant and impact-resistant composite low-voltage power cable according to claim 5, characterized in that: The material of the second insulating layer is a cross-linked polyethylene with a temperature resistance of 125° C. and a magnesium hydroxide additive added thereto.

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