Fireproof and flame-retardant power transmission line cable and preparation method thereof

Abstract

The application discloses a fireproof and flame-retardant power transmission line cable and a preparation method thereof. The cable is arranged in the inside of a protection pipe and is uniformly distributed. The side surface of the protection pipe is penetrated by and fixedly connected with a flame-retardant assembly. The cable is arranged on the side surface of the flame-retardant assembly and is in contact with the side surface of the flame-retardant assembly. The protection pipe comprises an outer flame-retardant pipe. The inner wall of the outer flame-retardant pipe is fixedly connected with an elastic protection layer. The inner wall of the elastic protection layer is fixedly connected with an inner flame-retardant pipe. The side surface of the outer flame-retardant pipe is in contact with the inner wall side surface of an adjusting device. The flame-retardant assembly penetrates the side surface of the outer flame-retardant pipe and is fixedly connected with the side surface of the outer flame-retardant pipe. The elastic protection layer comprises a fixed ring. The side surface of the fixed ring is fixedly connected with a forward spiral ring. The side surface of the forward spiral ring is fixedly connected with a reverse spiral ring. The side surface of the reverse spiral ring is fixedly connected with the side surface of the fixed ring.

Description

Technical Field

[0001] This invention relates to the field of power transmission line cable technology, specifically to a fire-resistant and flame-retardant power transmission line cable and its preparation method. Background Technology

[0002] The background technology of fire-resistant and flame-retardant power transmission cables has evolved continuously with people's deepening understanding of the hazards of fire. From the initial simple requirement of "not spreading flames," it has developed into a comprehensive pursuit of environmental protection, fire resistance integrity, and overall protective effectiveness. Its technological trajectory mainly revolves around two main lines: material innovation and structural design. The concept of fire-resistant cables can be traced back to the late 19th century. In 1896, a Swiss engineer proposed the idea of ​​mineral-insulated cables and applied for a patent. This concept laid the foundation for the most basic technical path of fire-resistant cables for decades to come. In the 1930s, France, Britain and other countries began to produce cables with annealed copper as conductor and magnesium oxide as insulation. With the development of polymer materials science, fire-resistant and flame-retardant cables gradually formed two parallel technical routes. The first route utilizes the non-flammability of materials to ensure the integrity of the circuit in flames. The second route has excellent fire resistance, high temperature resistance, explosion resistance, corrosion resistance, and long service life, truly achieving "fire resistance". The third route has a complex manufacturing process, high cost, poor bending performance, difficult installation, low smoke output during combustion, and does not produce toxic halogen acid gases, which is conducive to personnel escape. In order to achieve the flame-retardant effect, a large amount of flame retardant (often exceeding 50%) needs to be added, which will degrade the mechanical and processing properties of the material. Taking the widely used metal hydroxide flame retardants (such as aluminum hydroxide and magnesium hydroxide) as an example, their flame-retardant mechanism is multi-faceted: when heated and decomposed, they absorb heat and cool down, while generating a dense metal oxide protective film to isolate oxygen and inhibit free radical reactions.

[0003] CN105185436B discloses a single-core fire-resistant and flame-retardant high-voltage cable, wherein the sheath layer is made of low-smoke halogen-free polyethylene or a specially formulated material. The cable of this invention features a simple structure, superior fire resistance and flame-retardant properties, and effectively protects the sheath layer from external contact in the event of a fire, thus making the cable safer and more reliable. Summary of the Invention

[0004] To address the problems in existing technologies where bending of cables easily leads to cable breakage and the lack of active cooling and flame-retardant measures, the present invention provides the following technical solution: a fire-resistant and flame-retardant power transmission line cable and its preparation method, comprising: a fixing base, wherein the side of the fixing base serves as a support for the cable, an adjustment device is sleeved and threadedly connected to the side of the fixing base, and a protective tube is rotatably connected to the side of the adjustment device; The cable is disposed inside the protective tube and is evenly distributed. A flame-retardant component is fixedly connected to the side of the protective tube. The cable is disposed on the side of the flame-retardant component and contacts the side of the flame-retardant component. The protective tube includes an outer flame-retardant tube, an elastic protective layer is fixedly connected to the inner wall of the outer flame-retardant tube, an inner flame-retardant tube is fixedly connected to the inner wall of the elastic protective layer, the side of the outer flame-retardant tube contacts the side of the inner wall of the adjustment device, and the flame-retardant component penetrates the side of the outer flame-retardant tube and is fixedly connected to the side of the outer flame-retardant tube.

[0005] Preferably, the elastic protective layer includes a fixing ring, a forward spiral ring is fixedly connected to the side of the fixing ring, a reverse spiral ring is fixedly connected to the side of the forward spiral ring, and the side of the reverse spiral ring is fixedly connected to the side of the fixing ring.

[0006] The fixing ring is sleeved on the side of the inner flame-retardant tube and fixedly connected to the side of the inner flame-retardant tube. The fixing ring is set on the inner wall of the outer flame-retardant tube and fixedly connected to the inner wall of the outer flame-retardant tube. The fixing seat is used to fix the cable. After the adjustment device fixes the cable, it tightens and stretches it to ensure that the cable is in an extended state. The protective tube protects the cable. Flame retardancy is achieved through the composite structure of the outer and inner flame-retardant tubes. The cable is used to transmit electricity. The flame-retardant component is used to actively dissipate heat from the cable, thereby reducing the risk of the cable overheating and burning. The elastic support of the fixing ring and the forward and reverse spiral rings ensures the support strength of the outer and inner flame-retardant tubes.

[0007] To reduce the degree of bending during cable laying and prevent excessive deformation and damage, the elasticity of the forward and reverse spiral rings increases the elasticity between the outer and inner flame-retardant tubes, while also increasing their tensile strength. The materials of the forward and reverse spiral rings ensure the strength between the outer and inner flame-retardant tubes. The outer and inner flame-retardant tubes are fixedly connected by passing through the gap between the forward and reverse spiral rings, thereby increasing the overall strength of the outer flame-retardant tube and reducing the overheating problem caused by cable bending.

[0008] Preferably, the flame-retardant component includes a guide tube, a water supply pipe connected to the side of the guide tube, a connector connected to the side of the water supply pipe, drainage holes at the top and bottom of the guide tube, a support component fixedly connected to the inner wall of the guide tube, the water supply pipe passing through the side of the outer flame-retardant tube and fixedly connected to the side of the outer flame-retardant tube, and the guide tube being disposed on the side of the cable and in contact with the side of the cable.

[0009] The support assembly includes a support tube with a pressure relief hole on its side. A support plate is fixedly connected to the side of the support tube, and an elastic rod is fixedly connected to the side of the support tube. The side of the support tube contacts the inner wall of the guide tube. The flame-retardant liquid is transported through the connector into the interior of the water supply pipe and then into the interior of the guide tube.

[0010] The liquid is released through the drain holes and enters the interior of the elastic protective layer, immersing the entire cable in the flame-retardant liquid. This provides heat dissipation and cooling, and the flame-retardant liquid reduces the risk of combustion. The multiple drain holes help reduce local blockage caused by cable bending. When the cable bends, the bend of the guide tube moves multiple support components, which in turn move the support tube. The triangular design of the pressure relief holes facilitates the flow of liquid through the bend, preventing blockage inside the guide tube caused by bending.

[0011] The support plate facilitates the support of the inner wall of the guide tube, avoiding damage caused by rigid contact between the support tube and the inner wall of the guide tube. The elastic rod facilitates the elasticity between multiple sets of support tubes, thereby increasing the strength of the cable. The liquid delivery and output through multiple sets of joints reduces the overall temperature of the cable, and the flame-retardant liquid wrapping of the cable reduces the probability of cable ignition.

[0012] Preferably, the adjustment device includes a fixed base, an adjusting nut rotatably connected to the side of the fixed base, a rotating base rotatably connected to the side of the fixed base away from the adjusting nut, a fixed plate slidably connected to the side of the rotating base, a fastening nut sleeved and threadedly connected to the side of the fixed plate, the adjusting nut sleeved on the side of the fixed base and threadedly connected to the side of the fixed base, and the side of the fixed plate contacting the side of the outer flame-retardant tube.

[0013] Preferably, the rotating base includes an adjusting base, a support ring is fixedly connected to the side of the adjusting base, a brake strip is fixedly connected to the side of the support ring, a limiting groove is formed on the side of the adjusting base away from the support ring, a fixing groove adapted to the brake strip is formed on the side of the fixed base, and a fixing plate is disposed inside the limiting groove and slidably connected to the side of the adjusting base.

[0014] Preferably, the fixing plate includes a contact plate, a threaded ring is fixedly connected to the top of the contact plate, a sliding strip adapted to the limiting groove is fixedly connected to the side of the contact plate, a brake ring is fixedly connected to the inner wall of the contact plate, a guide groove is provided on one side of the contact plate, the contact plate is slidably connected to the inner wall of the limiting groove through the sliding strip, and the fastening nut is sleeved on the side of the contact plate and threadedly connected to the contact plate through the threaded ring.

[0015] During cable installation, cables are independently fixed using different installation nodes. During fixing, the side of the fixing base contacts the cable's fixing hole. The fixing base and rotating base are fitted onto the side of the outer flame-retardant tube. The fixing plate slides along the side of the rotating base. When the contact plate contacts the side of the cable, the contact plate drives the brake ring to contact the side of the cable. The threaded ring facilitates the tightening of the nut and the side of the contact plate. The guide groove facilitates progressive fixing. The sliding strip facilitates the sliding of the contact plate along the side of the rotating base. When the contact plate slides along the limiting groove, it increases the contact area of ​​the adjusting base with the cable. Rotating the tightening nut causes the contact plate to contact and fix the side of the cable. The adjusting base facilitates the sliding fixation of the fixing plate.

[0016] The support ring secures the brake strip. The side of the fixing base has a groove that matches the brake strip. After the cable is fixed, it can be adjusted by rotating the base. The rotation of the base rotates the cable, thereby adjusting the fixing angle of the cable. This makes it easy to eliminate the stress on the cable by rotating it after the wiring is completed, reducing the risk of damage and fire caused by cable twisting. During the process of fastening the cable to the contact plate, the support tube ensures that the fixation is tight and stable.

[0017] A method for preparing a fire-resistant and flame-retardant power transmission line cable, comprising: S1. Conductor drawing and stranding: The copper rod is drawn into a cable, the drawing die is fixed by the fixing seat, the tension is controlled by the adjustment device, and the stranded wire core is guided by the protective tube and enters the annealing furnace for softening. The elastic protective layer initially wraps the conductor to prevent oxidation. S2. Three-layer co-extrusion and shielding: The conductor shielding layer, insulation layer and inner flame-retardant tube are extruded simultaneously through the die head. The insulation shielding layer is wrapped with copper strip and equipped with fixing ring. The outside of the protective tube is equipped with forward spiral ring and reverse spiral ring to enhance the compressive and bending performance. S3. Multi-core cabling and flame retardancy: Insulated cores are twisted and arranged around flame retardant components, and PVC sheaths are extruded as outer flame retardant tubes. Internally, guide tubes and water supply pipes are embedded, joints are connected to the cooling system, vent holes are used to discharge moisture, and support tubes are kept round. S4. Terminal Fixing and Testing: Install the fixed base and rotating base, adjust the centering angle with the adjusting nut, use the support plate and elastic rod to buffer vibration, tighten the nut to lock it, release the internal pressure through the pressure relief hole, and complete the high-pressure offline test.

[0018] The beneficial effects of the technical solution provided by this invention include: 1. The mounting bracket secures the cable in the designated position. The adjustment device applies tensile force after the cable is fixed, keeping it extended and preventing slack. The protective tube provides protection for the cable; the composite structure of the outer and inner flame-retardant tubes works together to achieve a flame-retardant effect. The cable is used for power transmission; the flame-retardant components actively dissipate heat, helping to reduce cable temperature and minimizing the possibility of combustion due to overheating. The fixing ring, in conjunction with the forward and reverse spiral rings, provides elastic support for the outer and inner flame-retardant tubes, enhancing overall strength and reducing the degree of bending during cable laying, preventing excessive deformation and damage. The elastic properties of the forward and reverse spiral rings provide buffering capacity between the outer and inner flame-retardant tubes while increasing tensile strength. The material of these spiral rings ensures a stable inter-tube structure; the outer and inner flame-retardant tubes are fixedly connected through the spiral ring gaps, increasing overall strength and reducing heat accumulation after cable bending.

[0019] 2. Flame-retardant liquid is delivered through connectors into the water supply pipe and guide pipe, and then released from the drain holes into the elastic protective layer, ensuring the cable is completely immersed in the flame-retardant liquid. The liquid's enveloping heat dissipation helps cool the cable and forms a barrier, reducing the risk of combustion. Multiple drain holes maintain liquid flow when the cable is bent, preventing local blockage. When the cable bends, the guide pipe bends accordingly, moving the support components. The triangular structure of the pressure relief holes ensures the liquid flows smoothly through the bending area, preventing blockage inside the guide pipe. The support plate supports the inner wall of the guide pipe, preventing rigid contact with the support pipe that could cause damage. The elastic rod provides elasticity to the multiple support pipes, enhancing the overall strength of the cable. The liquid is circulated through multiple connectors, continuously reducing the cable temperature, and the encapsulation of the flame-retardant liquid effectively reduces the possibility of cable ignition.

[0020] 3. During cable installation, each installation node is independently fixed. The side of the fixing base aligns with the cable fixing hole, and the fixing base and rotating base are fitted onto the side of the outer flame-retardant tube. The fixing plate slides along the side of the rotating base, and when the contact plate contacts the side of the cable, the brake ring also contacts the cable. The threaded ring secures the fastening nut to the side of the contact plate, the guide groove achieves progressive fixing, and the sliding strip guides the contact plate to slide along the rotating base. As the contact plate moves along the limiting slide groove, the contact area of ​​the adjusting base with the cable increases. Rotating the fastening nut presses the contact plate against the side of the cable, and the adjusting base facilitates the sliding fixation of the fixing plate. The support ring fixes the brake strip, and the slide groove on the side of the fixing base is adapted to the brake strip. After the cable is fixed, rotating the adjusting base can rotate the cable to adjust the fixing angle. In this way, after the wiring is completed, rotating the cable can eliminate internal stress and reduce the risk of damage and combustion caused by torsion. During the contact plate tightening process, the support tube ensures a stable fixation and keeps the cable stable. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the fire-resistant and flame-retardant power transmission line cable structure of the present invention; Figure 2 This is a schematic diagram of the protective tube structure of the present invention; Figure 3 This is a schematic diagram of the elastic protective layer structure of the present invention; Figure 4 This is a schematic diagram of the flame-retardant component structure of the present invention; Figure 5 This is a schematic diagram of the supporting component structure of the present invention; Figure 6 This is a schematic diagram of the adjustment device structure of the present invention; Figure 7 This is a schematic diagram of the rotating base structure of the present invention; Figure 8 This is a schematic diagram of the fixing plate structure of the present invention; Figure 9 This is a schematic diagram of the manufacturing process of the fire-resistant and flame-retardant power transmission line cable of the present invention.

[0022] In the diagram: 1. Fixing base; 2. Adjustment device; 3. Protective tube; 4. Cable; 5. Flame-retardant component; 301. Outer flame-retardant tube; 302. Elastic protective layer; 303. Inner flame-retardant tube; 3021. Fixing ring; 3022. Forward spiral ring; 3023. Reverse spiral ring; 501. Guide tube; 502. Water supply pipe; 503. Connector; 504. Drain hole; 505. Support component; 5051. Support tube; 5052. Drain 5053, support plate; 5054, elastic rod; 201, fixed base; 202, adjusting nut; 203, rotating base; 204, fixed plate; 205, fastening nut; 2031, adjusting base; 2032, support ring; 2033, brake bar; 2034, limit groove; 2041, contact plate; 2042, threaded ring; 2043, sliding bar; 2044, brake ring; 2045, guide groove. Detailed Implementation

[0023] Example 1, please refer to Figures 1-3This invention provides a technical solution: a fire-retardant power transmission line cable and its preparation method. A fixing base 1 is used to fix the cable. An adjusting device 2 tightens and stretches the cable after fixing it, ensuring the cable remains in an extended state. A protective tube 3 protects the cable 4. Flame retardancy is achieved through a composite structure of an outer flame-retardant tube 301 and an inner flame-retardant tube 303. The cable 4 is used for power transmission. A flame-retardant component 5 actively dissipates heat from the cable, reducing the risk of overheating and combustion. The elastic support of a fixing ring 3021, a forward spiral ring 3022, and a reverse spiral ring 3023 ensures the support strength of the outer flame-retardant tube 301 and the inner flame-retardant tube 303, reducing the risk of overheating and combustion. The degree of bending during cable installation prevents excessive deformation and damage. The elasticity of the forward spiral ring 3022 and the reverse spiral ring 3023 increases the elasticity between the outer flame-retardant tube 301 and the inner flame-retardant tube 303, while also increasing their tensile strength. The materials of the forward spiral ring 3022 and the reverse spiral ring 3023 ensure the strength between the outer flame-retardant tube 301 and the inner flame-retardant tube 303. The outer flame-retardant tube 301 and the inner flame-retardant tube 303 are fixedly connected by passing through the gap between the forward spiral ring 3022 and the reverse spiral ring 3023, thereby increasing the overall strength of the outer flame-retardant tube 301 and reducing the overheating problem caused by cable bending.

[0024] Example 2, please refer to Figures 1-5 Based on the first embodiment, the flame-retardant liquid is conveyed through the connector 503 into the water supply pipe 502 and then into the guide pipe 501. The liquid is released through the drain hole 504 and enters the elastic protective layer 302, immersing the cable 4 entirely in the flame-retardant liquid. This provides a wrapping effect for heat dissipation and cooling, and reduces the risk of combustion by enveloping the cable 4 in the flame-retardant liquid. The multiple drain holes 504 help reduce local blockage caused by cable bending. When the cable bends, the guide pipe 501 bends, causing multiple support components 505 to move. The guide pipe 501 drives the support components... The pipe 5051 is movable, and the triangular design of the pressure relief hole 5052 facilitates the flow of liquid through the bend, preventing blockage inside the guide pipe 501 caused by the bend. The support plate 5053 provides support for the inner wall of the guide pipe 501, preventing damage caused by rigid contact between the support pipe 5051 and the inner wall of the guide pipe 501. The elastic rod 5054 provides elasticity between the multiple sets of support pipes 5051, thereby increasing the strength of the cable. The liquid delivery and output through the multiple sets of connectors 503 reduces the overall temperature of the cable, and the flame-retardant liquid wrapping around the cable 4 reduces the probability of the cable catching fire.

[0025] Example 3, please refer to Figures 1-8Based on the second embodiment, during cable installation, independent fixing is achieved through different installation nodes. During fixing, adjusting nut 202 is used to adjust the cable tightness, thereby fixing the cable shape. The side of fixing base 1 contacts the cable fixing hole. Fixing base 201 and rotating base 203 are fitted onto the side of outer flame-retardant tube 301. Fixing plate 204 slides along the side of rotating base 203. When contact plate 2041 contacts the side of the cable, contact plate 2041 drives brake ring 2044 to contact the side of the cable. The threaded ring 2042 facilitates threaded fastening of nut 205 to the side of contact plate 2041. The guide groove 2045 facilitates progressive fixing. The sliding strip 2043 facilitates sliding of contact plate 2041 along the side of rotating base 203. When contact plate... 2041 slides along the limiting groove 2034 to increase the contact area of ​​the adjustment base 2031 with the cable. Rotating the fastening nut 205 causes the contact plate 2041 to contact and fix with the side of the cable. The setting of the adjustment base 2031 facilitates the sliding fixation of the fixing plate 204. The support ring 2032 fixes the brake strip 2033. The side of the fixing base 201 has a groove that matches the brake strip 2033. After the cable is fixed, it is adjusted by rotating the adjustment base 2031. The rotation of the adjustment base 2031 causes the cable to rotate and adjust, thereby adjusting the fixing angle of the cable. This makes it easy to eliminate the stress of the cable by rotating the cable after the wiring is completed, reducing the risk of damage and fire caused by cable torsion. During the process of the contact plate 2041 tightening the cable, the support tube 5051 ensures that the fixation is tight and stable.

[0026] Example 4, please refer to Figures 1-9 Based on the second embodiment, a method for preparing a fire-resistant and flame-retardant power transmission line cable includes: S1. Conductor drawing and stranding: The copper rod is drawn into a cable 4, the drawing die is fixed by the fixing seat 1, the tension is controlled by the adjusting device 2, the stranded wire core is guided by the protective tube 3 and enters the annealing furnace to soften, and the elastic protective layer 302 initially wraps the conductor to prevent oxidation. S2. Three-layer co-extrusion and shielding: The conductor shielding layer, the insulation layer and the inner flame-retardant tube 303 are extruded simultaneously through the die head. The insulation shielding layer is wrapped with copper strip and equipped with a fixing ring 3021. The protective tube 3 is provided with a forward spiral ring 3022 and a reverse spiral ring 3023 to enhance the compressive and bending performance. S3. Multi-core cabling and flame retardancy: The insulated wire cores are twisted around the flame retardant component 5 and arranged. A PVC sheath is extruded as the outer flame retardant tube 301. A guide tube 501 and a water supply tube 502 are embedded inside. The connector 503 connects to the cooling system. The drain hole 504 discharges moisture. The support tube 5051 maintains the circular shape. S4. Terminal Fixing and Testing: Install the fixed base 201 and the rotating base 203, adjust the centering angle with the adjusting nut 202, use the support plate 5053 and the elastic rod 5054 to buffer vibration, tighten the nut 205 to lock, release the internal pressure through the pressure relief hole 5052, and complete the high-pressure offline test.

[0027] The above are merely specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. The scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A fire-resistant and flame-retardant power transmission line cable, characterized in that, include: The fixed base (1) has a side surface that serves as a support for the cable. An adjustment device (2) is fitted onto and threaded onto the side surface of the fixed base (1). A protective tube (3) is rotatably connected to the side surface of the adjustment device (2). Cable (4), the cable (4) is set inside the protective tube (3) and is evenly distributed, the side of the protective tube (3) is penetrated and fixedly connected to the flame retardant component (5), the cable (4) is set on the side of the flame retardant component (5) and contacts the side of the flame retardant component (5); The protective tube (3) includes an outer flame-retardant tube (301), an elastic protective layer (302) is fixedly connected to the inner wall of the outer flame-retardant tube (301), an inner flame-retardant tube (303) is fixedly connected to the inner wall of the elastic protective layer (302), the side of the outer flame-retardant tube (301) is in contact with the inner wall side of the adjusting device (2), and the flame-retardant component (5) penetrates the side of the outer flame-retardant tube (301) and is fixedly connected to the side of the outer flame-retardant tube (301).

2. The fire-resistant and flame-retardant power transmission line cable according to claim 1, characterized in that: The elastic protective layer (302) includes a fixing ring (3021), a forward spiral ring (3022) is fixedly connected to the side of the fixing ring (3021), a reverse spiral ring (3023) is fixedly connected to the side of the forward spiral ring (3022), the side of the reverse spiral ring (3023) is fixedly connected to the side of the fixing ring (3021), the fixing ring (3021) is sleeved on the side of the inner flame retardant tube (303) and fixedly connected to the side of the inner flame retardant tube (303), and the fixing ring (3021) is disposed on the inner wall of the outer flame retardant tube (301) and fixedly connected to the inner wall of the outer flame retardant tube (301).

3. The fire-resistant and flame-retardant power transmission line cable according to claim 1, characterized in that: The flame-retardant component (5) includes a guide pipe (501), a water supply pipe (502) connected to the side of the guide pipe (501), a connector (503) connected to the side of the water supply pipe (502), drainage holes (504) provided at the top and bottom of the guide pipe (501), a support component (505) fixedly connected to the inner wall of the guide pipe (501), the water supply pipe (502) passing through the side of the outer flame-retardant pipe (301) and fixedly connected to the side of the outer flame-retardant pipe (301), and the guide pipe (501) is located on the side of the cable (4) and contacts the side of the cable (4).

4. The fire-resistant and flame-retardant power transmission line cable according to claim 3, characterized in that: The support assembly (505) includes a support tube (5051), a pressure relief hole (5052) is provided on the side of the support tube (5051), a support plate (5053) is fixedly connected to the side of the support tube (5051), an elastic rod (5054) is fixedly connected to the side of the support tube (5051), and the side of the support tube (5051) is in contact with the inner wall of the guide tube (501).

5. The fire-resistant and flame-retardant power transmission line cable according to claim 1, characterized in that: The adjustment device (2) includes a fixed base (201), an adjusting nut (202) is rotatably connected to the side of the fixed base (201), a rotating base (203) is rotatably connected to the side of the fixed base (201) away from the adjusting nut (202), a fixed plate (204) is slidably connected to the side of the rotating base (203), a fastening nut (205) is sleeved and threadedly connected to the side of the fixed plate (204), the adjusting nut (202) is sleeved on the side of the fixed base (1) and threadedly connected to the side of the fixed base (1), and the side of the fixed plate (204) is in contact with the side of the outer flame retardant tube (301).

6. The fire-resistant and flame-retardant power transmission line cable according to claim 5, characterized in that: The rotating base (203) includes an adjusting base (2031), a support ring (2032) is fixedly connected to the side of the adjusting base (2031), a brake strip (2033) is fixedly connected to the side of the support ring (2032), and a limit groove (2034) is provided on the side of the adjusting base (2031) away from the support ring (2032).

7. A fire-resistant and flame-retardant power transmission line cable according to claim 6, characterized in that: The fixed base (201) has a fixed groove on its side that is compatible with the brake bar (2033), and the fixed plate (204) is set inside the limiting slide groove (2034) and slidably connected to the side of the adjusting base (2031).

8. A fire-resistant and flame-retardant power transmission line cable according to claim 6, characterized in that: The fixing plate (204) includes a contact plate (2041), a threaded ring (2042) is fixedly connected to the top of the contact plate (2041), a sliding strip (2043) adapted to the limiting slide groove (2034) is fixedly connected to the side of the contact plate (2041), a brake ring (2044) is fixedly connected to the inner wall of the contact plate (2041), and a guide groove (2045) is provided on one side of the contact plate (2041).

9. A fire-resistant and flame-retardant power transmission line cable according to claim 8, characterized in that: The contact plate (2041) is slidably connected to the inner wall of the limiting groove (2034) via a sliding strip (2043), and the fastening nut (205) is sleeved on the side of the contact plate (2041) and threadedly connected to the contact plate (2041) via a threaded ring (2042).

10. A method for preparing a fire-resistant and flame-retardant power transmission line cable, characterized in that, include: S1. Conductor drawing and stranding: The copper rod is drawn into a cable (4), the drawing die is fixed by the fixing seat (1), the tension is controlled by the adjusting device (2), the stranded wire core is guided by the protective tube (3) and enters the annealing furnace for softening, and the elastic protective layer (302) initially wraps the conductor to prevent oxidation; S2. Three-layer co-extrusion and shielding: The conductor shielding layer, the insulation layer and the inner flame-retardant tube (303) are extruded simultaneously through the die head. The insulation shielding layer is wrapped with copper strip and fitted with a fixing ring (3021). The protective tube (3) is provided with a forward spiral ring (3022) and a reverse spiral ring (3023) to enhance the compressive and bending performance. S3. Multi-core cabling and flame retardancy: The insulated wire cores are twisted around the flame retardant component (5), and a PVC sheath is extruded as an outer flame retardant tube (301). A guide tube (501) and a water supply tube (502) are embedded inside. The connector (503) connects to the cooling system, the drain hole (504) discharges moisture, and the support tube (5051) maintains a circular shape. S4. Terminal Fixing and Testing: Install the fixed base (201) and the rotating base (203), adjust the centering angle with the adjusting nut (202), use the support plate (5053) and elastic rod (5054) to buffer vibration, tighten the nut (205) to lock, release the internal pressure with the pressure relief hole (5052) to complete the high-pressure offline test.

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