Type-wire stranded copper conductor cross-linked polyethylene insulated medium-voltage power cable and preparation method thereof

Abstract

The present invention provides a cross-linked polyethylene insulated medium-voltage power cable with a stranded copper conductor and a preparation method thereof, comprising a cable core, a shielding layer, a composite fire-blocking layer and an outer sheath, wherein the composite fire-blocking layer comprises a second fire-blocking tape and an expansion layer carrier tape sequentially distributed from the inside to the outside, wherein the second fire-blocking tape is wrapped around the outside of the shielding layer along a first direction, and the expansion layer carrier tape is wrapped around the outside of the second fire-blocking tape along a second direction, the inner layer of the expansion layer carrier tape is adhered with a second fire-blocking expansion layer, and the expansion layer carrier tape is provided with a plurality of broken grooves distributed in a matrix, and the expansion layer carrier tape forms scales corresponding to the broken grooves, so that the second fire-blocking expansion layer of the inner layer can flip the scales radially outward in an expanded state, so that the thickness of the fire barrier formed by the second fire-blocking expansion layer on the outside of the shielding layer is thicker, thereby improving the temperature resistance time of the fire barrier.

Description

Technical Field

[0001] The invention relates to the technical field of electric wires and cables, and in particular to a cross-linked polyethylene insulated medium-voltage power cable with a stranded copper conductor and a preparation method thereof. Background Art

[0002] The stranded medium-voltage power cable is widely used in medium-voltage power systems that require efficient, stable and reliable power transmission due to its compact conductor design with high filling factor, excellent electrical transmission performance and mechanical stability. As an important part of the power system, medium-voltage power cable carries the task of transmitting large-capacity electric energy. Once a short circuit, overload or other fault occurs in the cable, it may cause a fire accident and cause significant losses to the power system. Therefore, the medium-voltage power cable needs to have good fire-resistant properties to effectively prevent the occurrence of fire accidents.

[0003] At present, the fire-retardant measures on medium-voltage power cables are generally fire-retardant coatings and fire-retardant tapes on the surface of the cables. The fire-retardant coating can form a protective film at high temperatures to isolate oxygen and heat, thereby slowing down the burning rate of the cable. The fire-retardant tape will rapidly expand to form a carbonized body when exposed to flames to prevent the burning of the cable. The fire-retardant coating and the fire-retardant isolation layer formed by the fire-retardant tape have a fire-retardant ability that is often affected by their thickness. Generally, the thicker the thickness, the longer the fire-retardant time. Therefore, increasing the thickness of the fire-retardant isolation layer during a fire can improve the overall fire-retardant ability of the cable. Summary of the invention

[0004] The first aspect of the present invention provides a cross-linked polyethylene insulated medium voltage power cable with stranded copper conductor, comprising:

[0005] The cable core comprises a twisted wire core and a filling rope, and the wire core and the filling rope are wrapped by a wrapping layer to form a cable core with a circular cross section;

[0006] A shielding layer, braided and wrapped around the outer side of the wrapping layer;

[0007] A composite fire barrier layer wrapped around the outer side of the shielding layer;

[0008] An outer sheath, extruded and coated on the outside of the composite fire barrier layer;

[0009] Wherein, the composite fire barrier layer comprises a second fire barrier tape and an expansion layer carrier tape sequentially distributed from the inside to the outside, the second fire barrier tape is wrapped around the outside of the shielding layer along the first direction, the expansion layer carrier tape is wrapped around the outside of the second fire barrier tape along the second direction, the inner layer of the expansion layer carrier tape is adhered with a second fire barrier expansion layer, and the expansion layer carrier tape is provided with a plurality of broken grooves distributed in a matrix, and the expansion layer carrier tape forms scales corresponding to the broken grooves, so that the second fire barrier expansion layer of the inner layer can turn the scales radially outward in an expanded state;

[0010] The thickness of the second fire-resistant expansion layer on the scale is greater than that of the second fire-resistant expansion layer on the expansion layer carrier tape.

[0011] Preferably, the break groove can be configured as a "C" shape, a "匚" shape, or a "V" shape, so that the scale part is integrally connected to the expansion layer carrier tape.

[0012] Preferably, both the second fire-resistant tape and the expansion layer carrier tape include mica tapes, and the second fire-resistant expansion layer includes a fire-resistant expansion adhesive layer.

[0013] Preferably, the wire core includes a plurality of mutually stranded wires and an insulating layer extruded and coated on the outer side of the wires.

[0014] Preferably, the filling rope includes a rope core and a first fire-resistant tape wound around the outer side of the rope core. The rope core includes a polyethylene or polyvinyl chloride strip, and the first fire-resistant tape includes a flame-retardant foam layer.

[0015] Preferably, a first fire-resistant expansion layer is adhered to the inner side surface of the first fire-resistant tape. The first fire-resistant tape is provided with a plurality of equally spaced notches along the axial direction of the rope core, so that the first fire-resistant tape between any two adjacent notches can be turned outward in the radial direction when the inner first fire-resistant expansion layer is in an expanded state.

[0016] Preferably, the diameter ratio of the filling rope to the rope core is 2 to 5.

[0017] Preferably, the first fire-resistant expansion layer includes a fire-resistant expansion adhesive layer, and the coating thickness of the first fire-resistant expansion layer gradually decreases in the direction close to the rope core.

[0018] Preferably, the distance between any two adjacent notches is set to 20 cm to 50 cm.

[0019] In the second aspect of the present invention, a method for manufacturing a type-stranded copper conductor cross-linked polyethylene insulated medium-voltage power cable is proposed, including the following steps:

[0020] Step 1, preparing a cable core:

[0021] Step 1.1, preparing a wire core: Using a stranding machine to mutually strand a plurality of wires to form a conductor, and after compacting the conductor, using an extruder to extrude an insulating layer on the outer side of the conductor in a three-layer co-extrusion manner to make the wire core;

[0022] Step 1.2, preparing a filling rope: extruding a rope core through an extruder in advance, then coating a first fire-blocking expansion layer on the surface of a first fire-blocking belt, and cutting notches of a set width equidistantly on the first fire-blocking belt along the length direction, and then winding the first fire-blocking belt around the outside of the rope core with the first fire-blocking expansion layer facing inward, and with the notches on the outside, to make the filling rope;

[0023] Step 1.3, wrapping: wrapping the wrapping tape around the outer side of the wire core and the filling rope to form a wrapping layer, and forming a cable core with a circular cross section;

[0024] Step 2, preparing a shielding layer: using a braiding machine to weave a copper mesh on the outside of the wrapping layer, and making the braiding density of the copper mesh greater than 85%, to form the shielding layer on the outside of the wrapping layer;

[0025] Step 3, preparing a composite fire barrier layer: pre-coating a second fire barrier expansion layer on the surface of the expansion layer carrier tape, then punching out broken grooves on the expansion layer carrier tape to form a plurality of scales, wrapping the second fire barrier tape forwardly on the outside of the shielding layer, and then making one side of the second fire barrier expansion layer face inward, and reversely wrapping the expansion layer carrier tape on the outside of the second fire barrier tape to form the composite fire barrier layer;

[0026] Step 4, preparing an outer sheath: using an extruder to extrude an insulating material to coat the outer side of the composite fire barrier layer to prepare the outer sheath.

[0027] Compared with the prior art, the advantages of the present invention are:

[0028] The present invention arranges a composite fire barrier layer on the inner side of the outer sheath, and the composite fire barrier layer includes a second fire barrier tape and an expansion layer carrier tape which are sequentially distributed from the inside to the outside. The inner layer of the expansion layer carrier tape is adhered with the second fire barrier expansion layer, and the surface of the expansion layer carrier tape is provided with scales. The inner second fire barrier expansion layer can flip the scales radially outward in an expanded state, so that the thickness of the fire barrier formed by the second fire barrier expansion layer on the outer side of the shielding layer is thicker, thereby improving the temperature resistance time of the fire barrier. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in various figures may be represented by the same reference numeral. For clarity, not every component is labeled in every figure. Embodiments of various aspects of the present invention will now be described by way of example and with reference to the accompanying drawings, in which:

[0030] Figure 1 It is a three-dimensional hierarchical structure schematic diagram of a cross-linked polyethylene insulated medium-voltage power cable with stranded copper conductor shown in an embodiment of the present invention;

[0031] Figure 2It is a schematic cross-sectional structural diagram of a cross-linked polyethylene insulated medium voltage power cable with stranded copper conductor shown in an embodiment of the present invention;

[0032] Figure 3 It is a schematic diagram of the hierarchical structure of a side view of a type wire stranded copper conductor cross-linked polyethylene insulated medium voltage power cable shown in an embodiment of the present invention;

[0033] Figure 4 is a schematic diagram of the structure of the filling rope in the unfolded state shown in the embodiment of the present invention;

[0034] Figure 5 It is a schematic diagram of a partial split structure of the composite fire barrier layer shown in an embodiment of the present invention;

[0035] 10. Wire core; 11. Conductor; 12. Insulation layer; 20. Filling rope; 21. Rope core; 22. First fire-blocking tape; 221. Slot; 23. First fire-blocking expansion layer; 30. Wrapping layer; 40. Shielding layer; 50. Composite fire-blocking layer; 51. Second fire-blocking tape; 52. Second fire-blocking expansion layer; 53. Expansion layer carrier tape; 531. Scales; 60. Outer sheath. DETAILED DESCRIPTION

[0036] In order to better understand the technical content of the present invention, specific embodiments are given and described as follows in conjunction with the accompanying drawings.

[0037] like Figure 1-Figure 5 As shown, the present invention provides a type of stranded copper conductor cross-linked polyethylene insulated medium-voltage power cable, which aims to increase the thickness of the fire-retardant isolation layer in the event of a fire, and can improve the overall fire-retardant ability of the cable. The cable mainly includes a cable core, a shielding layer 40, a composite fire-retardant layer 50 and an outer sheath 60.

[0038] The cable core includes a wire core 10 and a filling rope 20 twisted together, and the wire core 10 and the filling rope 20 are wrapped by a wrapping layer 30 to form a cable core with a circular cross-section.

[0039] Furthermore, the core 10 includes a plurality of conductors 11 twisted together in a regular twisting manner of 1+6+12+18 and an insulating layer 12 extruded and coated on the outside of the conductors 11, wherein the conductors 11 are made of annealed oxygen-free fine copper wire, which can improve the overall flexibility of the conductors 11, and the insulating layer 12 is made of three-layer co-extruded cross-linked polyethylene (XLPE) to improve the insulation strength of the cable and ensure that the cable can operate safely and stably in a high voltage and high electric field environment.

[0040] Furthermore, the filling rope 20 includes a rope core 21 and a first fire barrier strip 22 wound around the outside of the rope core 21, wherein the rope core 21 may be made of polyethylene or polyvinyl chloride strips, so that the filling rope 20 has a certain support in the center portion to prevent the filling rope 20 from being excessively compressed and deformed, thereby maintaining the roundness of the cable core; the first fire barrier strip 22 may be made of a flame retardant foam layer to enhance the overall flexibility of the cable through the compressibility of the flame retardant foam.

[0041] like Figure 4 As shown, a first fire-blocking expansion layer 23 is adhered to the inner side of the first fire-blocking belt 22, and the first fire-blocking belt 22 is provided with a plurality of equally distributed notches 221 along the axial direction of the rope core 21, so that the inner first fire-blocking expansion layer 23 can radially flip the first fire-blocking belt 22 between any two adjacent notches 221 outward in the expanded state.

[0042] In some embodiments, the first fire-retardant expansion layer 23 adopts a fire-retardant expansion adhesive layer. The fire-retardant expansion adhesive layer can use an emulsion resin as a base material, to which an expansion flame retardant system including an acid source, a carbon forming agent and a foaming agent, as well as fillers and additives are added to form a flame-retardant expansion adhesive layer, so that it can expand rapidly and form a flame-retardant barrier when encountering high temperature or flame.

[0043] Preferably, the coating thickness of the first fire-retardant expansion layer 23 gradually decreases in the direction approaching the rope core 21, and the distance between any two adjacent notches 221 is set to 20 cm to 50 cm.

[0044] like Figure 1 and Figure 2 As shown, the rope core 21 is in the center position, and the first fire barrier belt 22 with the first fire barrier expansion layer 23 is wrapped around the outside of the rope core 21. When the flame burns to the filling rope 20 and the outer shielding layer 40 is damaged, the first fire barrier expansion layer 23 will expand and squeeze the first fire barrier belt 22 outward. Since the area at the outer end of the first fire barrier belt 22 is not restrained, the first fire barrier belt 22 in the high temperature part will expand outward under the squeezing of the inner first fire barrier expansion layer 23, and the first fire barrier belt 22 will stretch outward around the center of the rope core 21 as the first fire barrier expansion layer 23 expands, gradually forming a thicker fire barrier.

[0045] Thus, compared with the current single-layer or multi-layer coated expansion layer, the expansion layer in this embodiment can drive the base tape (i.e., the first fire barrier tape 22) to unwind outward under the expansion condition, so that the first fire barrier tape 22 that was originally tightly wound becomes a looser winding state, further increasing the thickness of the fire barrier in the area.

[0046] Optionally, the ratio of the diameter of the filling rope 20 to the diameter of the rope core 21 is 2 to 5, so that the filling rope 20 has both flexibility and support, and can make the cable as a whole softer while keeping the cable core round.

[0047] Furthermore, the wrapping layer 30 can be made of mica tape or fiberglass tape, and is wrapped around the outside of the conductor core 10 and the filling rope 20 to make the cable core more round. The shielding layer 40 is braided and coated on the outside of the wrapping layer 30. The shielding layer 40 can be made of fine copper wires braided into a mesh structure and coated on the outside of the wrapping layer 30. The shielding layer 40 plays an important role in aspects such as electromagnetic shielding, grounding protection, and improving the electric field distribution.

[0048] Furthermore, the composite fireproof layer 50 is wrapped around the outside of the shielding layer 40, and the outer sheath 60 is extrusion-coated on the outside of the composite fireproof layer 50.

[0049] As Figure 5 shown, the composite fireproof layer 50 includes a second fireproof tape 51 and an expansion layer carrier tape 53 which are distributed in sequence from the inside to the outside. The second fireproof tape 51 is wrapped around the outside of the shielding layer 40 along the first direction, and the expansion layer carrier tape 53 is wrapped around the outside of the second fireproof tape 51 along the second direction.

[0050] Among them, the inner layer of the expansion layer carrier tape 53 is adhered with a second fireproof expansion layer 52, and a plurality of fracture grooves are formed in the expansion layer carrier tape 53 in a matrix distribution. Scales 531 are formed at the positions corresponding to the fracture grooves of the expansion layer carrier tape 53, so that the second fireproof expansion layer 52 on the inner layer can turn the scales 531 outward along the radial direction in the expanded state.

[0051] In this way, compared with the traditional method of spraying or filling fireproof expansion materials between hierarchical structures, the expansion thickness of the fixed-thickness expansion material is limited by the spraying amount or filling amount of the material even in the expanded state. However, in this embodiment, the scale 531 structure is arranged on the expansion layer carrier tape 53. When the material of the second fireproof expansion layer 52 expands, the scales 531 can be pushed outwards, enabling the material that could originally only expand radially to turn up in the radial direction and expand simultaneously in the axial and radial directions, expanding the expansion area and forming a thicker fireproof barrier.

[0052] In some embodiments, both the second fireproof tape 51 and the expansion layer carrier tape 53 can be made of mica tape. The second fireproof expansion layer 52 includes a fireproof expansion adhesive layer. The fireproof expansion adhesive layer can use emulsion resin as the base material, and an expansion flame retardant system including an acid source, a carbonizing agent, and a foaming agent, as well as fillers and additives are added to it to jointly form a flame retardant expansion adhesive layer, so that it can expand rapidly and form a fireproof barrier when encountering high temperature or flame.

[0053] In an alternative embodiment, the fracture grooves can be configured as "C" - shaped, "匚" - shaped, "V" - shaped, so that part of the scale 531 is integrally connected to the expansion layer carrier tape 53, enabling the scale 531 area to be turned over by the fireproof expansion adhesive layer expanding inward, and part of it is connected to the expansion layer carrier tape 53 to prevent the disordered expansion of the fireproof expansion adhesive layer.

[0054] Preferably, the thickness of the second fire-retardant expansion layer 52 on the scale 531 is greater than the thickness of the second fire-retardant expansion layer 52 on the expansion layer carrier 53. In this way, when the second fire-retardant expansion layer 52 on the inner part of the scale 531 encounters high temperature or flame, it can expand outward and flip part of the scale 531 outward, so that the fire barrier formed by the second fire-retardant expansion layer 52 on the outside of the shielding layer 40 is thicker, thereby improving the temperature resistance time of the fire barrier.

[0055] The second aspect of the present invention provides a method for preparing a profiled stranded copper conductor cross-linked polyethylene insulated medium voltage power cable, comprising the following steps:

[0056] Step 1: Prepare the cable core:

[0057] Step 1.1, preparing the wire core 10: using a twisting machine to twist a plurality of wires 11 twisted together in a regular twisting manner of 1+6+12+18 to form a conductor, and after the conductor is compressed by hydraulic pressure or mechanical pressure, an extruder is used to extrude an insulating layer 12 on the outside of the conductor in a three-layer co-extrusion manner to form the wire core 10.

[0058] Step 1.2, prepare the filling rope 20: extrude the rope core 21 through an extruder in advance, then coat the first fire-blocking expansion layer 23 on the surface of the first fire-blocking belt 22, and cut out notches 221 of a set width equidistantly on the first fire-blocking belt 22 along the length direction, and then make the first fire-blocking expansion layer 23 face inward and wind the first fire-blocking belt 22 on the outside of the rope core 21, and make the notches 221 on the outside to make the filling rope 20. The rope core 21 can be made of polyethylene or polyvinyl chloride strips, and the filling rope 20 has a certain support in the center to prevent the filling rope 20 from being excessively compressed and deformed, and maintain the roundness of the cable core. The first fire-blocking belt 22 can use a flame-retardant foam layer to improve the overall flexibility of the cable with the compressibility of the flame-retardant foam.

[0059] Step 1.3, wrapping: Wrapping the wrapping tape around the outer sides of the wire core 10 and the filling rope 20 to form a wrapping layer 30, and forming a cable core with a circular cross section.

[0060] Step 2, preparing the shielding layer 40: using a braiding machine to weave a copper mesh on the outside of the wrapping layer 30, and making the braiding density of the copper mesh greater than 85%, to form the shielding layer 40 on the outside of the wrapping layer 30.

[0061] Step 3, prepare the composite fire barrier layer 50: pre-coat the second fire barrier expansion layer 52 on the surface of the expansion layer carrier 53, then punch out broken grooves on the expansion layer carrier 53 to form a plurality of scales 531, wrap the second fire barrier tape 51 forwardly on the outside of the shielding layer 40, and then make one side of the second fire barrier expansion layer 52 face inward, and reversely wrap the expansion layer carrier 53 on the outside of the second fire barrier tape 51 to form a composite fire barrier layer 50. When the second fire barrier expansion layer 52 on the inner part of the scale 531 encounters high temperature or flame, it can expand outward and flip part of the scale 531 outward, so that the thickness of the fire barrier formed by the second fire barrier expansion layer 52 on the outside of the shielding layer 40 is thicker, thereby improving the temperature resistance time of the fire barrier.

[0062] Step 4, preparing the outer sheath 60 : using an extruder to extrude the insulating material and coat the outer side of the composite fire barrier layer 50 to form the outer sheath 60 .

[0063] In combination with the above embodiments, a composite fire barrier layer 50 is arranged on the inner side of the outer sheath 60, and the composite fire barrier layer 50 includes a second fire barrier tape 51 and an expansion layer carrier tape 53 which are distributed from the inside to the outside. The inner layer of the expansion layer carrier tape 53 is adhered with a second fire barrier expansion layer 52, and the surface of the expansion layer carrier tape 53 is provided with scales 531. The inner second fire barrier expansion layer 52 can flip the scales 531 radially outward in the expanded state, so that the fire barrier formed by the second fire barrier expansion layer 52 on the outside of the shielding layer 40 is thicker, thereby improving the temperature resistance time of the fire barrier.

[0064] Although the present invention has been disclosed as above with preferred embodiments, it is not intended to limit the present invention. A person with ordinary knowledge in the technical field to which the present invention belongs may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by the definition of the claims.

Claims

1. A type of stranded copper conductor cross-linked polyethylene insulated medium voltage power cable, characterized in that: Comprising: A cable core, including a stranded conductor core (10) and a filling rope (20), and the conductor core (10) and the filling rope (20) are wrapped by a wrapping layer (30) to form a cable core with a circular cross-section; A shielding layer (40), braided and coated on the outer side of the wrapping layer (30); A composite fireproof layer (50), wrapped on the outer side of the shielding layer (40); An outer sheath (60), extruded and coated on the outer side of the composite fireproof layer (50); Wherein, the composite fireproof layer (50) includes a second fireproof tape (51) and an expansion layer carrier tape (53) distributed in sequence from inside to outside. The second fireproof tape (51) is wrapped around the outer side of the shielding layer (40) along a first direction, the expansion layer carrier tape (53) is wrapped around the outer side of the second fireproof tape (51) along a second direction, a second fireproof expansion layer (52) is adhered to the inner layer of the expansion layer carrier tape (53), and a plurality of break grooves are arranged in a matrix on the expansion layer carrier tape (53). Scales (531) are formed at positions corresponding to the break grooves on the expansion layer carrier tape (53), so that the second fireproof expansion layer (52) on the inner layer can turn the scales (531) radially outward in an expanded state; The thickness of the second fireproof expansion layer (52) on the scales (531) is greater than the thickness of the second fireproof expansion layer (52) on the expansion layer carrier tape (53).

2. The cross-linked polyethylene insulated medium voltage power cable with stranded copper conductor according to claim 1, characterized in that: The break grooves can be configured as "C" - shaped, "匚" - shaped, "V" - shaped, so that the scales (531) are partially integrally connected to the expansion layer carrier tape (53).

3. The cross-linked polyethylene insulated medium voltage power cable with stranded copper conductor according to claim 1, characterized in that: Both the second fireproof tape (51) and the expansion layer carrier tape (53) include mica tapes, and the second fireproof expansion layer (52) includes a fireproof expansion glue layer.

4. The cross-linked polyethylene insulated medium voltage power cable with stranded copper conductor according to claim 1, characterized in that: The conductor core (10) includes a plurality of stranded conductors (11) and an insulating layer (12) extruded and coated on the outer side of the conductors (11).

5. The cross-linked polyethylene insulated medium voltage power cable with stranded copper conductor according to claim 1, characterized in that: The filling rope (20) includes a rope core (21) and a first fireproof tape (22) wound around the outer side of the rope core (21). The rope core (21) includes a polyethylene or polyvinyl chloride strip, and the first fireproof tape (22) includes a flame - retardant foam layer.

6. The cross-linked polyethylene insulated medium voltage power cable with stranded copper conductor according to claim 5, characterized in that: A first fireproof expansion layer (23) is adhered to the inner side surface of the first fireproof tape (22). A plurality of equally - spaced notches (221) are arranged along the axial direction of the rope core (21) on the first fireproof tape (22), so that the first fireproof tape (22) between any two adjacent notches (221) can be turned radially outward by the first fireproof expansion layer (23) on the inner layer in an expanded state.

7. The cross-linked polyethylene insulated medium voltage power cable with stranded copper conductor according to claim 6, characterized in that: The ratio of the diameter of the filling rope (20) to the diameter of the rope core (21) is 2 - 5.

8. The cross-linked polyethylene insulated medium voltage power cable with stranded copper conductor according to claim 6, characterized in that: The first fireproof expansion layer (23) includes a fireproof expansion glue layer, and the coating thickness of the first fireproof expansion layer (23) gradually decreases along the direction close to the rope core (21).

9. The cross-linked polyethylene insulated medium voltage power cable with stranded copper conductor according to claim 6, characterized in that: The distance between any two adjacent notches (221) is set to 20 cm - 50 cm.

10. A method for preparing the profiled stranded copper conductor cross-linked polyethylene insulated medium voltage power cable according to claim 6, characterized in that: Including the following steps: Step 1, preparing a cable core: Step 1.1, preparing the wire core (10): using a stranding machine to twist a plurality of wires (11) together to form a conductor, and after the conductor is compacted, using an extruder to extrude an insulating layer (12) on the outer side of the conductor in a three-layer co-extrusion manner to form the wire core (10); Step 1.2, preparing the filling rope (20): extruding the rope core (21) by an extruder in advance, then coating the first fire-blocking expansion layer (23) on the surface of the first fire-blocking belt (22), and cutting out notches (221) of a set width on the first fire-blocking belt (22) at equal intervals along the length direction, and then winding the first fire-blocking belt (22) on the outside of the rope core (21) with the first fire-blocking expansion layer (23) facing inward, and making the notches (221) on the outside, to prepare the filling rope (20); Step 1.3, wrapping: wrapping a wrapping tape around the outer sides of the wire core (10) and the filling rope (20) to form a wrapping layer (30), and forming a cable core with a circular cross section; Step 2, preparing the shielding layer (40): using a braiding machine to weave a copper mesh on the outside of the wrapping layer (30), and making the braiding density of the copper mesh greater than 85%, so as to form the shielding layer (40) on the outside of the wrapping layer (30); Step 3, preparing the composite fire barrier layer (50): pre-coating the second fire barrier expansion layer (52) on the surface of the expansion layer carrier tape (53), then punching out broken grooves on the expansion layer carrier tape (53) to form a plurality of scales (531), wrapping the second fire barrier tape (51) forwardly on the outside of the shielding layer (40), and then making one side of the second fire barrier expansion layer (52) face inward, and wrapping the expansion layer carrier tape (53) reversely on the outside of the second fire barrier tape (51) to form the composite fire barrier layer (50); Step 4, preparing the outer sheath (60): using an extruder to extrude an insulating material to coat the outer side of the composite fire barrier layer (50) to prepare the outer sheath (60).

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