High-heat-insulation low-heat-release medium-voltage fire-resistant cable

Abstract

The invention provides a high-heat-insulation low-heat-release medium-voltage fire-resistant cable, and relates to the technical field of cables, and the cable comprises a detection platform which sequentially comprises an outer sheath, a flame-retardant filler, a fire-resistant layer, a heat-insulating layer, an inner insulating layer, a high-temperature flame-retardant filling rope and a metal shielding layer from outside to inside. The metal shielding layer sequentially comprises an insulation shielding layer, an insulation layer, a conductor shielding layer, a conductor and an insulation wire core from outside to inside, the temperature of the outer surface of the cable can be smaller than or equal to 180 DEG C under the impact of flames of 1000 DEG C through the arrangement of the flame-retardant filler, the fireproof layer and the high-temperature flame-retardant filling rope, the surrounding environment is protected, and meanwhile the flame-retardant flame-retardant cable can be used as a flame-retardant cable. By arranging the heat insulation layer and the inner insulation layer, heat release during combustion can be reduced by more than 30%, the fire spreading risk is reduced, the arranged mica tape can release crystal water to reduce combustion heat and inhibit generation of smoke and toxic gas, and finally, the arranged outer sheath can prevent external mechanical damage and further resist flame and insulate heat.

Description

Technical Field

[0001] The present invention mainly relates to the technical field of cables, and specifically to a medium-voltage fire-resistant cable with high thermal insulation and low heat release. Background Art

[0002] With the development of society and the acceleration of urbanization, the demand for medium-voltage power cables in various large buildings, industrial facilities and public infrastructure continues to grow. In these application scenarios, the safety and reliability of cables are crucial, especially in extreme situations such as fires. Medium-voltage cables must have good fire resistance to ensure the continuity of power supply and buy precious time for personnel evacuation and fire rescue.

[0003] Cable is an electrical device used to transmit electrical energy, signals or electromagnetic energy. It is usually composed of conductors, insulation layers, shielding layers, sheaths and other parts. It has the characteristics of complex structure, diverse functions and wide application scenarios. There are many types of cables, which can be classified according to different dimensions such as purpose, voltage level, insulation material, structural characteristics, etc. Among them, the classification according to voltage level includes low-voltage cables, medium-voltage cables, high-voltage cables and ultra-high-voltage cables. Medium-voltage cables usually refer to cables with rated voltages between 6kV and 35kV, which are widely used in urban distribution networks, internal power supply systems of industrial enterprises and other fields. When a fire occurs, traditional medium-voltage cables face many severe challenges. On the one hand, the existing medium-voltage cables have insufficient thermal insulation performance. When encountering a fire, the high temperature generated by the flame will quickly transfer to the inside of the cable, causing the temperature of key components such as the insulation layer and conductor of the cable to rise sharply. Common insulating materials, such as cross-linked polyethylene (XLPE), are prone to thermal degradation at high temperatures, resulting in reduced insulation performance and even short-circuit failures, which in turn affects the stability of power transmission. On the other hand, traditional medium-voltage cables often release a lot of heat and smoke during the combustion process, which not only aggravates the spread of fire, but also seriously hinders the evacuation of personnel and fire rescue work. In addition, some cable materials will also produce toxic and harmful gases when burning, posing a great threat to the environment and human health.

[0004] At present, although there are some fire-resistant cables on the market, they still have obvious deficiencies in high thermal insulation and low heat release performance. The medium-voltage cables in the prior art have shortcomings when used: the medium-voltage cables in the prior art are prone to insulation failure due to high temperature in fire scenarios, causing short circuits or fire spread, and the traditional fire-resistant cables have insufficient thermal insulation performance, and heat is easily transferred to the outer layer, which may cause surrounding combustibles to burn. Therefore, we provide a high-insulation, low-heat-release medium-voltage fire-resistant cable to solve the defects of the prior art. Summary of the invention

[0005] The present invention mainly provides a medium-voltage fire-resistant cable with high thermal insulation and low heat release, so as to solve the technical problems raised in the above-mentioned background technology.

[0006] The technical solution adopted by the present invention to solve the above technical problems is:

[0007] A high-insulation, low-heat-release medium-voltage fire-resistant cable comprises a test bench, which comprises, from the outside to the inside, an outer sheath, a flame-retardant filler, a fire-resistant layer, a heat-insulating layer, an inner insulating layer, a high-temperature flame-retardant filling rope and a metal shielding layer, wherein the metal shielding layer comprises, from the outside to the inside, an insulating shielding layer, an insulating layer, a conductor shielding layer, a conductor and an insulated wire core.

[0008] Furthermore, the outer sheath is made of low-smoke halogen-free flame-retardant polyolefin material, and the thickness of the outer sheath is 2 to 4 mm.

[0009] Furthermore, the flame retardant filler is magnesium hydroxide, and a plurality of evenly distributed mica tapes are arranged inside the flame retardant filler.

[0010] Furthermore, the fire-resistant layer is a strip woven from spun ceramic fiber yarn reinforced with alkali-free glass yarn, and the thickness of the fire-resistant layer is 3 to 5 mm.

[0011] Furthermore, the heat insulation layer is made of a composite material of aerogel felt and ceramic fiber, the thermal conductivity of the heat insulation layer is ≤0.015W / (m·K), and the thickness of the heat insulation layer is 2-4mm.

[0012] Furthermore, the inner insulating layer is a halogen-free, low-smoke, and highly flame-retardant tape made of glass fiber yarn.

[0013] Furthermore, the high temperature flame retardant filling rope is made of ceramic fiber, and alumina (Al 2 O 3 ), silicon dioxide (SiO 2 ), containing a small amount of zirconium oxide (ZrO 2 ) is made by mixing process.

[0014] Furthermore, the insulating shielding layer is made of polyvinyl chloride (PVC) material, and the thickness of the insulating shielding layer is 2 to 3 mm.

[0015] Furthermore, the insulating layer is a ceramic silicone rubber composite material, and the thickness of the insulating layer is 2 to 3 mm.

[0016] Furthermore, the conductor shielding layer is made of semi-conductive polyethylene, and semi-conductive fillers (such as carbon black, carbon nanotubes) are added to the semi-conductive polyethylene.

[0017] Compared with the prior art, the present invention has the following beneficial effects:

[0018] The beneficial effects of the present invention are as follows: by arranging flame-retardant fillers, fire-resistant layers and high-temperature flame-retardant filling ropes, the outer surface temperature of the cable can be ≤180°C under the impact of a flame at 1000°C, thereby protecting the surrounding environment; at the same time, by arranging a heat-insulating layer and an inner insulating layer, the heat release during combustion can be reduced by more than 30%, thereby reducing the risk of fire spread; the mica tape arranged can be the mica tape and ceramic silicone rubber composite material adopted in the insulating layer, as well as the overall multi-layer protective structure design, so that the cable has excellent fire resistance; under continuous burning of a flame at 950°C, the cable can maintain the circuit integrity for more than 180 minutes, which is far higher than the industry standard requirements, thereby ensuring that a continuous and stable power supply can be provided to key equipment and systems when a fire occurs; the outer sheath arranged at last can prevent external mechanical damage, further provide flame retardancy and heat insulation, and the insulating shielding layer and the conductor shielding layer both adopt cross-linked semi-conductive materials, which synergize with the metal shielding layer to effectively homogenize the electric field distribution, reduce the occurrence of local discharge, and improve the insulation performance and withstand voltage capability of the cable.

[0019] The present invention will be explained in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings required for describing the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other accompanying drawings can be obtained based on these accompanying drawings without paying creative work.

[0021] Figure 1 This is a schematic diagram of the overall structure of a medium-voltage fire-resistant cable with high thermal insulation and low heat release according to the present invention;

[0022] Figure 2 A schematic diagram of the cutting structure of a medium-voltage fire-resistant cable with high thermal insulation and low heat release according to the present invention;

[0023] Figure 3 It is a schematic diagram of the front cross-sectional structure of a medium-voltage fire-resistant cable with high thermal insulation and low heat release according to the present invention;

[0024] Figure 4 A high heat insulation and low heat release medium voltage fire resistant cable of the present invention Figure 2 A magnified view of area A in;

[0025] Figure 5 A high heat insulation and low heat release medium voltage fire resistant cable of the present invention Figure 2 Magnified view of area B in .

[0026] In the figure: 1. outer sheath; 101. flame retardant filler; 102. mica tape; 103. fire-resistant layer; 104. heat insulation layer; 105. inner insulation layer; 106. high-temperature flame retardant filling rope; 2. metal shielding layer; 201. insulation shielding layer; 202. insulation layer; 203. conductor shielding layer; 204. conductor; 205. insulated core. DETAILED DESCRIPTION

[0027] In order to enable those skilled in the art to better understand the solution of the present application, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work should fall within the scope of protection of the present application.

[0028] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequential order. It should be understood that the data used in this way can be interchanged where appropriate, so that the embodiments of the present application described here. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device comprising a series of steps or units is not necessarily limited to those steps or units clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0029] In the present application, the terms "upper", "lower", "left", "right", "front", "back", "top", "bottom", "inner", "outer", "middle", "vertical", "horizontal", "lateral", "longitudinal" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings. These terms are mainly used to better describe the present application and its embodiments, and are not used to limit the indicated devices, elements or components to have a specific orientation, or to be constructed and operated in a specific orientation.

[0030] In addition, some of the above terms may be used to express other meanings in addition to indicating orientation or positional relationship. For example, the term "on" may also be used to express a certain dependency or connection relationship in some cases. For those of ordinary skill in the art, the specific meanings of these terms in this application can be understood according to specific circumstances.

[0031] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0032] For examples, please refer to the attached Figure 1-5 As shown, a high-insulation, low-heat-release medium-voltage fire-resistant cable comprises a test bench 3, which comprises, from the outside to the inside, an outer sheath 1, a flame-retardant filler 101, a fire-resistant layer 103, a heat-insulating layer 104, an inner insulating layer 105, a high-temperature flame-retardant filling rope 106 and a metal shielding layer 2. The metal shielding layer 2 comprises, from the outside to the inside, an insulating shielding layer 201, an insulating layer 202, a conductor shielding layer 203, a conductor 204 and an insulated core 205.

[0033] Among them, the outer sheath 1 is made of low-smoke halogen-free flame-retardant polyolefin material, the thickness of the outer sheath 1 is 2 to 4 mm, which can prevent external mechanical damage, further flame retardant and heat-insulating, and complies with the GB / T19216.21 standard, and can continuously supply power for ≥180 minutes in the flame.

[0034] Among them, the flame retardant filler 101 can be magnesium hydroxide, and a number of evenly distributed mica tapes 102 are arranged inside the flame retardant filler 101. The arranged mica tapes 102 are ceramic silicone rubber composite materials, which make the cable have excellent fire resistance. Under the continuous burning of 950°C flame, the cable can maintain the circuit integrity for more than 180 minutes, which is far higher than the industry standard requirements, ensuring that a continuous and stable power supply can be provided to key equipment and systems when a fire occurs.

[0035] The fire-resistant layer 103 is a belt material woven from spun ceramic fiber yarn reinforced with alkali-free glass yarn. The thickness of the fire-resistant layer 103 is 3 to 5 mm. The high-temperature flame-retardant filling rope 106 is made of ceramic fiber. Alumina (Al 2 O 3 ), silicon dioxide (SiO 2 ), containing a small amount of zirconium oxide (ZrO 2 ) is processed by mixing process, and the outer surface temperature of the cable can be ≤180℃ under the impact of 1000℃ flame, thus protecting the surrounding environment.

[0036] Among them, the heat insulation layer 104 is made of a composite material of aerogel felt and ceramic fiber. The thermal conductivity of the heat insulation layer 104 is ≤0.015W / (m·K). The thickness of the heat insulation layer 104 is 2-4mm. The inner insulation layer 105 is a halogen-free, low-smoke, and highly flame-retardant tape made of glass fiber yarn and low-smoke, halogen-free polyolefin material. It is extruded at 160-180°C, which can reduce heat release by more than 30% during combustion and reduce the risk of fire spread.

[0037] Among them, the insulating shielding layer 201 is made of polyvinyl chloride (PVC) material, the thickness of the insulating shielding layer 201 is 2 to 3 mm, the insulating layer 202 is a ceramic silicone rubber composite material, the thickness of the insulating layer 202 is 2 to 3 mm, and the conductor shielding layer 203 is made of semi-conductive polyethylene, and semi-conductive fillers (such as carbon black, carbon nanotubes) are added to the semi-conductive polyethylene. The insulating shielding layer 201 and the conductor shielding layer 203 both use cross-linked semi-conductive materials, which work synergistically with the metal shielding layer 2 to effectively homogenize the electric field distribution, reduce the occurrence of local discharge, and improve the insulation performance and voltage resistance of the cable.

[0038] The specific workflow of the present invention is:

[0039] Firstly, by arranging the flame retardant filler 101, the fire-resistant layer 103 and the high-temperature flame retardant filling rope 106, the outer surface temperature of the cable can be ≤180°C under the impact of a flame of 1000°C, thereby protecting the surrounding environment. At the same time, by arranging the heat insulation layer 104 and the inner insulating layer 105, the heat release during combustion can be reduced by more than 30%, thereby reducing the risk of fire spread. A double-layer mica tape 102 is used for wrapping, and magnesium hydroxide flame retardant glue (solid content ≥60%) is evenly coated in the middle. The mica tape 102 can release crystalline water to reduce the heat of combustion and inhibit the generation of smoke and toxic gases. Finally, the outer sheath 1 is arranged to prevent external mechanical damage, further provide flame retardancy and heat insulation, and comply with the GB / T19216.21 standard, and can continuously supply power for ≥180 minutes in the flame.

[0040] The above is an exemplary description of the present invention in combination with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as such non-substantial improvements are made by adopting the method concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A medium voltage fire-resistant cable with high thermal insulation and low heat release, comprising a test bench (3), characterized in that: The invention comprises, from the outside to the inside, an outer sheath (1), a flame retardant filler (101), a fire resistant layer (103), a heat insulating layer (104), an inner insulating layer (105), a high temperature flame retardant filling rope (106) and a metal shielding layer (2); the metal shielding layer (2) comprises, from the outside to the inside, an insulating shielding layer (201), an insulating layer (202), a conductor shielding layer (203), a conductor (204) and an insulating core (205).

2. A medium voltage fire-resistant cable with high thermal insulation and low heat release according to claim 1, characterized in that: The outer sheath (1) is made of low-smoke, halogen-free, flame-retardant polyolefin material, and the thickness of the outer sheath (1) is 2 to 4 mm.

3. A medium voltage fire-resistant cable with high thermal insulation and low heat release according to claim 1, characterized in that: The flame retardant filler (101) is magnesium hydroxide, and a plurality of evenly distributed mica tapes (102) are arranged inside the flame retardant filler (101).

4. A medium voltage fire-resistant cable with high thermal insulation and low heat release according to claim 1, characterized in that: The fire-resistant layer (103) is a strip woven from spun ceramic fiber yarns reinforced with alkali-free glass yarns, and the thickness of the fire-resistant layer (103) is 3 to 5 mm.

5. A medium voltage fire-resistant cable with high thermal insulation and low heat release according to claim 1, characterized in that: The heat insulation layer (104) is made of a composite material of aerogel felt and ceramic fibers; the heat conductivity of the heat insulation layer (104) is ≤0.015 W / (m·K); and the thickness of the heat insulation layer (104) is 2 to 4 mm.

6. A medium voltage fire-resistant cable with high thermal insulation and low heat release according to claim 1, characterized in that: The inner insulating layer (105) is a halogen-free, low-smoke, and highly flame-retardant tape made of glass fiber yarn.

7. A medium voltage fire-resistant cable with high thermal insulation and low heat release according to claim 1, characterized in that: The high temperature flame retardant filling rope (106) is made of ceramic fiber, and is processed by a mixing process of adding alumina, silicon dioxide and zirconium oxide into the ceramic fiber.

8. A medium voltage fire-resistant cable with high thermal insulation and low heat release according to claim 1, characterized in that: The insulating shielding layer (201) is made of polyvinyl chloride material, and the thickness of the insulating shielding layer (201) is 2 to 3 mm.

9. A medium voltage fire-resistant cable with high thermal insulation and low heat release according to claim 1, characterized in that: The insulating layer (202) is a ceramic silicone rubber composite material, and the thickness of the insulating layer (202) is 2 to 3 mm.

10. A medium voltage fire-resistant cable with high thermal insulation and low heat release according to claim 1, characterized in that: The conductor shielding layer (203) is made of semi-conductive polyethylene, and semi-conductive fillers are added into the semi-conductive polyethylene.

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