Flame-retardant b1 class medium-voltage fire-resistant power cable

Abstract

The utility model belongs to the technical field of power cable, especially a kind of fire -retardant B1-grade medium voltage fire -resistant power cable, present and propose the following scheme, including conductor, the outside of the conductor is filled with filling layer, the outside of the filling layer is surrounded and is wrapped with conductor shield layer;By setting main insulation layer, can effectively improve heat resistance, avoid under high temperature condition, long time high temperature influence, cause damage to the insulating layer of cable, so that the problem of fire outbreak appears;Main insulation layer adopts crosslinked polyethylene (XLPE) insulation layer, can insulate conductor and external structure, withstand the working voltage and short time overvoltage (such as lightning overvoltage, operating overvoltage) of medium voltage system, prevent electric leakage or breakdown;Meanwhile, crosslinked polyethylene is greatly improved after crosslinking treatment (long-term resistance 90 DEG C, short-circuit resistance 250 DEG C / 5s), can adapt to the long-term operating temperature requirement of medium voltage cable, and excellent anti-aging performance, prolong the service life of cable.

Description

Technical Field

[0001] This utility model relates to the field of power cable technology, and in particular to a flame-retardant B1-grade medium-voltage fire-resistant power cable. Background Technology

[0002] Flame-retardant B1-grade medium-voltage fire-resistant power cables are special cables that integrate three core functions: "medium-voltage power transmission", "B1-grade high flame retardancy" and "continuous power supply in fire". They are designed specifically for medium-voltage power distribution systems with stringent requirements for fire safety and power supply reliability, and are widely used in densely populated places and critical facilities.

[0003] Flame-retardant B1-grade medium-voltage fire-resistant power cables have four main performance characteristics: flame retardancy, slow fire spread during combustion and control within a certain range, meeting the B1-grade flame retardancy requirements of GB31247, while also meeting the additional requirements of no burning drips (d0), low toxicity (t0), and low corrosivity (a1), producing less smoke and having a low impact on light transmittance at disaster sites; fire resistance, with some medium-voltage fire-resistant cables employing heat-insulating and oxygen-barrier fire-resistant technologies, such as a combination structure of a semi-conductive buffer layer, a halogen-free low-smoke flame-retardant polyolefin oxygen barrier layer, a ceramicized polyolefin heat insulation layer, and a ceramicized silicone rubber fire-resistant layer outside the insulated core; electrical performance, typically using cross-linked polyethylene insulation, possessing excellent electrical performance, heat resistance, and mechanical strength, allowing for long-term operation at 90℃; and mechanical performance, with the design of the outer sheath and armor layer (if applicable) providing good tensile, compressive, and abrasion resistance, adapting to different laying environments.

[0004] Existing B1-grade medium-voltage fire-resistant power cables have relatively weak corrosion resistance. In humid, saline-alkali (such as coastal areas) or chemical environments, long-term use may lead to sheath corrosion and perforation, which in turn causes the internal mineral insulation layer to absorb moisture. On the other hand, B1-grade medium-voltage fire-resistant power cables have certain limitations in fire resistance, especially under high-temperature conditions. Prolonged exposure to high temperatures can easily damage the cable insulation layer, leading to fires.

[0005] Therefore, a flame-retardant B1-grade medium-voltage fire-resistant power cable is needed. Utility Model Content

[0006] This utility model proposes a flame-retardant B1-grade medium-voltage fire-resistant power cable, which solves the problems of existing B1-grade medium-voltage fire-resistant power cables having weak corrosion resistance. In humid, saline (such as coastal areas) or chemical environments, long-term use may lead to sheath corrosion and perforation, resulting in moisture absorption by the internal mineral insulation layer. On the other hand, B1-grade medium-voltage fire-resistant power cables have certain limitations in fire resistance, especially under high-temperature conditions. Prolonged exposure to high temperatures can easily damage the cable insulation layer, leading to fires.

[0007] To achieve the above objectives, this utility model provides the following technical solution: A flame-retardant B1-grade medium-voltage fire-resistant power cable includes a conductor, the conductor being filled with a filler layer, a conductor shielding layer being wrapped around the outside of the filler layer, and an insulation layer being wrapped around the outside of the conductor shielding layer. The insulating layer structure includes a main insulating layer, and an insulating shielding layer surrounds the outside of the main insulating layer.

[0008] Preferably, the outer side of the insulating shielding layer is surrounded by a fire-resistant layer, and the outer side of the fire-resistant layer is surrounded by an oxygen-barrier layer.

[0009] Preferably, the outer side of the oxygen barrier layer is surrounded by an armor layer, and the outer side of the armor layer is surrounded by an outer sheath layer.

[0010] Preferably, the conductor is composed of three strands of twisted copper wire in a spiral, and the filler layer fills the gap between the conductor and the conductor shielding layer.

[0011] Preferably, the inner side of the main insulation layer adopts a hollow groove structure, the main insulation layer is made of cross-linked polyethylene material, the interior of the main insulation layer presents a three-dimensional mesh structure, and the main insulation layer and the conductor shielding layer are tightly bonded.

[0012] Preferably, the outer side of the insulating shielding layer adopts a hollow groove design, the insulating shielding layer adopts an ultra-slippery semi-conductive shielding material with acetylene carbon black conductive filler, and the insulating shielding layer and the main insulating layer have a tightly bonded structure.

[0013] Preferably, the fire-resistant layer is composed of a ceramicized polyolefin strip and a ceramicized silicone rubber layer. The fire-resistant layer and the oxygen barrier layer are in a tightly bonded structure. The oxygen barrier layer is made of halogen-free, low-smoke, flame-retardant polyolefin material, and the oxygen barrier layer has vertically opened holes on its side.

[0014] Preferably, the armor layer is composed of two layers of galvanized steel strips wrapped in a crisscross pattern, the outer sheath layer is made of halogen-free, low-smoke, flame-retardant polyolefin high flame-retardant sheath material, and the outer side of the outer sheath layer is provided with a groove.

[0015] This utility model proposes a flame-retardant B1-grade medium-voltage fire-resistant power cable. Compared with the prior art, the beneficial effects of this utility model are: By setting a main insulation layer, heat resistance can be effectively improved, avoiding damage to the cable insulation layer caused by prolonged high temperatures under high-temperature conditions, which could lead to fires. The main insulation layer uses cross-linked polyethylene (XLPE) insulation, which can isolate the conductor from the external structure, withstand the working voltage and short-term overvoltage (such as lightning overvoltage and switching overvoltage) of the medium-voltage system, and prevent leakage or breakdown. At the same time, after cross-linking treatment, the heat resistance of XLPE is greatly improved (long-term resistance to 90℃, short-circuit resistance to 250℃ / 5s), which can meet the long-term operating temperature requirements of medium-voltage cables, and has excellent anti-aging properties, extending the service life of the cable. 2. By setting up an armor layer and an outer sheath layer, corrosion and perforation of the sheath can be avoided, which would lead to moisture absorption by the internal mineral insulation layer. The core function of the armor layer is to resist external mechanical forces, such as soil compression during direct burial, friction during pipe installation, and impacts during construction, protecting the internal insulation and fire-resistant layers. On the other hand, the galvanized layer can improve the corrosion resistance to soil and moisture, extending the service life of the cable in harsh environments. At the same time, the outer sheath layer can isolate moisture, dust, and chemical corrosive media (such as acids, alkalis, and salt spray) in the external environment, preventing the internal structure from getting damp or corroded. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the overall structure of a flame-retardant B1-grade medium-voltage fire-resistant power cable proposed in this utility model; Figure 2 This is a schematic diagram of the overall structure of a flame-retardant B1-grade medium-voltage fire-resistant power cable proposed in this utility model; Figure 3 This is a partial structural schematic diagram of a flame-retardant B1-grade medium-voltage fire-resistant power cable proposed in this utility model; Figure 4 This is a partial structural schematic diagram of a flame-retardant B1-grade medium-voltage fire-resistant power cable proposed in this utility model.

[0017] In the diagram: 1. Conductor; 2. Filler layer; 3. Conductor shielding layer; 4. Main insulation layer; 5. Insulation shielding layer; 6. Fire-resistant layer; 7. Oxygen barrier layer; 8. Armoring layer; 9. Outer sheath layer. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] Please see Figure 1-4This utility model provides a technical solution: a flame-retardant B1 grade medium-voltage fire-resistant power cable, including a conductor 1, a filling layer 2 filling the outside of the conductor 1, a conductor shielding layer 3 surrounding the outside of the filling layer 2, and an insulation layer mechanism surrounding the outside of the conductor shielding layer 3. The insulation layer structure includes a main insulation layer 4, and an insulating shielding layer 5 surrounds the outside of the main insulation layer 4.

[0020] Furthermore, the outer side of the insulating shielding layer 5 is surrounded by a fire-resistant layer 6, and the outer side of the fire-resistant layer 6 is surrounded by an oxygen-barrier layer 7.

[0021] Furthermore, the outer side of the oxygen barrier layer 7 is surrounded by an armor layer 8, and the outer side of the armor layer 8 is surrounded by an outer sheath layer 9.

[0022] Furthermore, conductor 1 is composed of a spiral of three stranded copper wires, and filler layer 2 is filled in the gap between conductor 1 and conductor shielding layer 3. Conductor 1, which is composed of a spiral of three stranded copper wires, has the advantages of excellent conductivity and good mechanical toughness. Filler layer 2 is filled with flame-retardant filler, and magnesium hydroxide and aluminum hydroxide are added as flame retardants. At high temperature, magnesium hydroxide and aluminum hydroxide will decompose and absorb heat, thus protecting the internal structure.

[0023] Furthermore, the inner side of the main insulation layer 4 adopts a hollow groove structure, the main insulation layer 4 is made of cross-linked polyethylene, the interior of the main insulation layer 4 presents a three-dimensional mesh structure, and the main insulation layer 4 and the conductor shielding layer 3 are tightly bonded; the main insulation layer 4 is made of cross-linked polyethylene (XLPE) insulation layer, which can isolate the conductor 1 from the external structure, withstand the working voltage and short-time overvoltage (such as lightning overvoltage, switching overvoltage) of the medium voltage system, and prevent leakage or breakdown.

[0024] Furthermore, the outer side of the insulating shielding layer 5 adopts a hollow groove design, and the insulating shielding layer 5 uses a super-slippery semi-conductive shielding material with acetylene carbon black conductive filler. The insulating shielding layer 5 and the main insulating layer 4 are in a tightly fitted structure. The conductor 1 and the conductor shielding layer 3 form an "electric field closed loop", which confines the electric field in the insulating layer between "conductor shielding-insulation-insulation shielding" to avoid the electric field overflow affecting the outer structure.

[0025] Furthermore, the fire-resistant layer 6 is composed of a ceramicized polyolefin tape and a ceramicized silicone rubber layer. The fire-resistant layer 6 and the oxygen barrier layer 7 are tightly bonded together. The oxygen barrier layer 7 is made of halogen-free, low-smoke, flame-retardant polyolefin material, and vertical holes are opened on the side of the oxygen barrier layer 7. The fire-resistant layer 6 is flexible and fire-resistant, which is the core of the cable's "fire resistance". In the event of a fire (external flame temperature 950-1000℃), it blocks the penetration of flames and high temperatures into the insulation layer through its own ceramicization (forming a hard ceramic shell at high temperatures) or the high-temperature resistance of mineral materials, ensuring that the internal temperature of the insulation layer is below 300℃ (GB / T19666 requirement). The design of the holes can prevent the oxygen barrier layer 7 from deforming due to thermal expansion and contraction.

[0026] Furthermore, the armor layer 8 is constructed by double-layer galvanized steel strips wrapped in a crisscross pattern, and the outer sheath layer 9 is made of halogen-free, low-smoke, flame-retardant polyolefin high flame-retardant sheath material. The outer sheath layer 9 has grooves on its outer side. The core function of the armor layer 8 is to resist external mechanical forces, such as soil compression during direct burial, friction during pipe insertion, and impacts during construction, protecting the internal insulation and fire-resistant layer 6. On the other hand, the galvanized layer can improve the corrosion resistance to soil and moisture, extending the service life of the cable in harsh environments. At the same time, the outer sheath layer 9 can isolate moisture, dust, and chemical corrosive media (such as acids, alkalis, and salt spray) in the external environment, preventing the internal structure from getting damp or corroded. The groove design on the outer side of the outer sheath layer 9 can increase frictional resistance and make it easier for workers to handle when wearing gloves.

[0027] Working principle: First, this flame-retardant B1 grade medium-voltage fire-resistant power cable is composed of multiple layers. The conductor 1, which is formed by three strands of twisted copper wire spiral, has the advantages of excellent conductivity and good mechanical toughness. The filling layer 2 is filled with flame-retardant filler, and magnesium hydroxide and aluminum hydroxide are added as flame retardants. At high temperature, magnesium hydroxide and aluminum hydroxide will decompose and absorb heat, protecting the internal structure. Next, the main insulation layer 4 is made of cross-linked polyethylene (XLPE) insulation layer, which can isolate conductor 1 from the external structure, withstand the working voltage and short-time overvoltage (such as lightning overvoltage, switching overvoltage) of the medium voltage system, and prevent leakage or breakdown. Then, conductor 1 and conductor shielding layer 3 form an "electric field closed loop", which confines the electric field in the insulation layer between "conductor shielding-insulation-insulation shielding" to prevent the electric field from overflowing and affecting the outer structure; Finally, the fire-resistant layer 6 is flexible and fire-resistant, which is the core of the cable's "fire resistance". In the event of a fire (external flame temperature 950-1000℃), it blocks the penetration of flames and high temperatures into the insulation layer through its own ceramization (forming a hard ceramic shell at high temperatures) or the high-temperature resistance of mineral materials, ensuring that the internal temperature of the insulation layer is below 300℃ (GB / T19666 requirement). At the same time, the core function of the armor layer 8 is to resist external mechanical forces, such as soil compression during direct burial, friction during pipe insertion, and impacts during construction, protecting the internal insulation and fire-resistant layer 6. On the other hand, the galvanized layer can improve the corrosion resistance to soil and moisture, extending the cable's service life in harsh environments. Meanwhile, the outer sheath layer 9 can isolate moisture, dust, and chemical corrosive media (such as acids, alkalis, and salt spray) in the external environment, preventing the internal structure from getting damp or corroded.

[0028] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A flame-retardant B1-grade medium-voltage fire-resistant power cable, comprising a conductor (1), characterized in that: The conductor (1) is filled with a filling layer (2) on the outside, and a conductor shielding layer (3) is wrapped around the outside of the filling layer (2), and an insulating layer is wrapped around the outside of the conductor shielding layer (3). The insulating layer structure includes a main insulating layer (4), and an insulating shielding layer (5) surrounds the outside of the main insulating layer (4).

2. The flame-retardant B1-grade medium-voltage fire-resistant power cable according to claim 1, characterized in that: The outer side of the insulating shielding layer (5) is surrounded by a fire-resistant layer (6), and the outer side of the fire-resistant layer (6) is surrounded by an oxygen-barrier layer (7).

3. The flame-retardant B1-grade medium-voltage fire-resistant power cable according to claim 2, characterized in that: The outer side of the oxygen barrier layer (7) is surrounded by an armor layer (8), and the outer side of the armor layer (8) is surrounded by an outer sheath layer (9).

4. The flame-retardant B1-grade medium-voltage fire-resistant power cable according to claim 1, characterized in that: The conductor (1) is made of three strands of twisted copper wire spiral, and the filling layer (2) fills the gap between the conductor (1) and the conductor shielding layer (3).

5. A flame-retardant B1-grade medium-voltage fire-resistant power cable according to claim 1, characterized in that: The inner side of the main insulation layer (4) adopts a hollow groove structure. The main insulation layer (4) is made of cross-linked polyethylene material. The interior of the main insulation layer (4) presents a three-dimensional mesh structure. The main insulation layer (4) and the conductor shielding layer (3) are in a tightly fitted structure.

6. The flame-retardant B1-grade medium-voltage fire-resistant power cable according to claim 1, characterized in that: The outer side of the insulating shielding layer (5) adopts a hollow groove design. The insulating shielding layer (5) adopts an ultra-slippery semi-conductive shielding material with acetylene carbon black conductive filler. The insulating shielding layer (5) and the main insulating layer (4) are in a tightly fitted structure.

7. A flame-retardant B1-grade medium-voltage fire-resistant power cable according to claim 2, characterized in that: The fire-resistant layer (6) is composed of a ceramicized polyolefin strip and a ceramicized silicone rubber layer. The fire-resistant layer (6) and the oxygen barrier layer (7) are in a tightly bonded structure. The oxygen barrier layer (7) is made of halogen-free, low-smoke, flame-retardant polyolefin material. The oxygen barrier layer (7) has vertical holes on its side.

8. A flame-retardant B1-grade medium-voltage fire-resistant power cable according to claim 3, characterized in that: The armor layer (8) is made of double-layer galvanized steel strips wrapped in a crisscross pattern, and the outer sheath layer (9) is made of halogen-free, low-smoke, flame-retardant polyolefin high flame-retardant sheath material. The outer sheath layer (9) has a groove on its outer side.

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