Crosslinked polyethylene insulated flame-retardant power cable and production equipment

Abstract

The application relates to the technical field of power cables, and particularly discloses a cross-linked polyethylene insulation flame-retardant power cable and a production device.The cross-linked polyethylene insulation flame-retardant power cable comprises a deformable inner support pipe, the outer periphery of the inner support pipe is inwardly recessed to form three accommodating grooves, a conductor is arranged in each accommodating groove and is attached to the inner wall of the accommodating groove, a deformable pipe body is arranged in the inner support pipe, the outer periphery of the inner support pipe is wrapped with an expanded graphite wrapping tape, the outer periphery of the expanded graphite wrapping tape is wrapped with a binding wrapping tape, and the outer periphery of the binding wrapping tape is provided with an outer sheath.The cross-linked polyethylene insulation flame-retardant power cable reduces the heat transfer speed of heat transfer to the conductor in a fire, improves the fire resistance of the power cable, the conductor has a high heat dissipation speed and a good heat dissipation effect, and the power cable guarantees power transmission efficiency.The cross-linked polyethylene insulation flame-retardant power cable production device makes the production of the cross-linked polyethylene insulation flame-retardant power cable convenient, and the produced power cable has good fire resistance.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of power cable, in particular to a cross-linked polyethylene insulation flame-retardant power cable and production equipment. BACKGROUND

[0002] The power cable is a key component in the power transmission system, and undertakes the task of transmitting and distributing electric energy. The cross-linked polyethylene insulation flame-retardant power cable is widely used in medium and low voltage power transmission due to its excellent heat resistance, chemical stability and electrical performance. In order to improve the flame retardant performance of the power cable, the outer sheath of the flame-retardant cross-linked polyethylene material outside the conductor is thickened. The thicker the outer sheath, the better the flame retardant effect of the power cable, but the worse the heat dissipation performance of the outer sheath, and the lower the long-term allowable current-carrying capacity of the power cable, which directly reduces the power transmission efficiency of the power cable. SUMMARY

[0003] The technical problem to be solved by the present application is to overcome the existing defects, provide a cross-linked polyethylene insulation flame-retardant power cable and production equipment, which reduces the heat transfer speed to the conductor during fire, improves the fire resistance of the cross-linked polyethylene insulation flame-retardant power cable, and makes the heat dissipation speed of the conductor fast and the heat dissipation effect good, ensuring the power transmission efficiency of the power cable. The cross-linked polyethylene insulation flame-retardant power cable production equipment makes the production of cross-linked polyethylene insulation flame-retardant power cable convenient, and the produced power cable has good fire resistance.

[0004] The technical solution adopted by the present application to solve its technical problem comprises:

[0005] On the one hand, a cross-linked polyethylene insulation flame-retardant power cable is provided, which comprises a deformable inner support pipe. The outer periphery of the inner support pipe is inwardly recessed to form three accommodating grooves. The three accommodating grooves are arranged at equal angles around the axis of the inner support pipe on the outer periphery of the inner support pipe. A conductor is arranged in each accommodating groove and is in contact with the inner wall of the accommodating groove. A deformable pipe body is arranged in the inner support pipe. An expanded graphite wrapping tape is wrapped around the outer periphery of the inner support pipe. A restraining wrapping tape is wrapped around the outer periphery of the expanded graphite wrapping tape. An outer sheath made of flame-retardant cross-linked polyethylene material is arranged outside the restraining wrapping tape.

[0006] The pipe body is made of elastic material and / or the two ends of the pipe body are closed. The inner support pipe is filled with fluorinated liquid. The conductor is pressed against the pipe body through the inner support pipe.

[0007] When the conductor is subjected to an external force directed towards the pipe body, the conductor deforms the pipe body to increase the deformation amount of the pipe body. The external force directed towards the pipe body decreases, and the deformation amount of the pipe body decreases.

[0008] As a preferred technical solution of the present application, the inner support pipe is made of soft material.

[0009] As a preferred technical scheme of the present application, three elastic partitions are fixed on the outer periphery of the pipe body at equal angles around the axis of the pipe body, and an elastic partition is inserted between any two adjacent conductors.

[0010] As a preferred technical scheme of the present application, the inner support pipe is made of elastic material.

[0011] As a preferred technical scheme of the present application, the inner wall of the inner support pipe is fixedly connected to the outer periphery of the pipe body, and the inner cavity of the inner support pipe is divided into three divided cavities.

[0012] As a preferred technical scheme of the present application, the ratio of the outer diameter of the pipe body to the outer diameter of the conductor is 1.0:2.0-6.1, and the ratio of the distance between the two edges of the accommodating groove on the inner support pipe to the diameter of the conductor is 1.0:5.0-20.0.

[0013] As a preferred technical scheme of the present application, the binding tape is a glass silk tape, an aluminum tape or a copper tape.

[0014] As a preferred technical scheme of the present application, the two edges of the accommodating groove on the inner support pipe are filled with an expanded graphite filler.

[0015] In another aspect, a production device for cross-linked polyethylene insulation flame-retardant power cable is also provided, which is used for producing a cross-linked polyethylene insulation flame-retardant power cable with a soft material inner support pipe, and comprises a horn shell, three conductor guides are arranged on the inner wall of the horn shell at equal angles near the large end, three conductor limiters are fixed on the inner wall of the horn shell at equal angles, the length direction of the conductor limiters is parallel to the axial direction of the horn shell, one end of the conductor limiters is close to the small end of the horn shell, and the other end of the conductor limiters is close to one of the conductor guides, a support is fixed on the outer side of the horn shell, a rotating ring is installed on the support to rotate, an expanded graphite tape support frame is installed on the rotating ring, and a driving mechanism is installed on the support to drive the rotating ring to rotate.

[0016] The large end of the horn shell faces upward, a tray with expanded graphite tape wound thereon is installed on the expanded graphite tape support frame, a pipe body is inserted into the inner support pipe, the inner support pipe and the three conductors pass through the horn shell from the large end of the horn shell downward, one conductor is slidably attached to each conductor guide, the inner support pipe is located between the three conductors, the lower end of the inner support pipe is closed, fluorinated liquid is filled in the inner support pipe, one end of the expanded graphite tape is fixed on the inner support pipe, the inner support pipe and the three conductors move downward synchronously, the driving mechanism drives the rotating ring to rotate the tray, and the expanded graphite tape is wound on the inner support pipe away from the small end of the horn shell.

[0017] The outer diameter of the three accommodating grooves formed by the inner diameter of the inner wall of the horn shell near the small end of the horn shell and the outer circumferential side of the inner support tube being inwardly recessed is equal to the outer diameter after the three accommodating grooves are formed.

[0018] As a preferred technical scheme of the present application, the driving mechanism comprises a motor, a gear is fixed on the motor, and the gear and the outer gear ring are engaged.

[0019] Compared with the prior art, the present application has the following beneficial effects:

[0020] 1、The crosslinked polyethylene insulation flame-retardant power cable provided by the present application has the following advantages: on the one hand, when a fire occurs, the restraint tape makes the expanded graphite on the expanded graphite tape expand inward, the expanded graphite that expands inward provides an action force to the conductor that points to the pipe body, the pipe body is deformed by the conductor, the deformation amount of the pipe body is increased, the expanded graphite makes the heat transfer speed from the restraint tape to the conductor slow, and the fire resistance of the crosslinked polyethylene insulation flame-retardant power cable is improved; on the other hand, a part of the heat generated by the conductor is transferred to the fluorinated liquid through the inner support tube, the temperature of the fluorinated liquid near the inner wall of the inner support tube is increased, the temperature of the fluorinated liquid in the inner cavity of the inner support tube is inconsistent, the fluorinated liquid flows, the temperature of the conductor is controlled, and the reliability of the crosslinked polyethylene insulation flame-retardant power cable for power transmission is ensured; on the other hand, when the conductor abnormally generates heat, the heat generated by the conductor makes the fluorinated liquid in the inner cavity of the inner support tube evaporate, the fluorinated liquid vapor generated by evaporation gradually liquefies during movement in the inner support tube, and the heat dissipation speed of the conductor is fast and the heat dissipation effect is good.

[0021] 2、The crosslinked polyethylene insulation flame-retardant power cable provided by the present application has the following advantages: the elastic partition plate divides the conductor, so that the three conductors can move to the pipe body, the inner support tube and the fluorinated liquid in the inner support tube can relatively move during bending of each conductor, the minimum bending radius of the crosslinked polyethylene insulation flame-retardant power cable is small, and the use range of the crosslinked polyethylene insulation flame-retardant power cable is improved.

[0022] 3、The crosslinked polyethylene insulation flame-retardant power cable production equipment provided by the present application has the following advantages: during downward movement of the conductor in the horn shell, the conductor extrudes the accommodating grooves on the inner support tube, the conductor limiting piece makes the distance between the conductor and the pipe body smaller and smaller, the distance between the two edges of the accommodating grooves gradually becomes smaller, and the conductor is fixed on the inner support tube conveniently. BRIEF DESCRIPTION OF DRAWINGS

[0023] Figure 1 It is an embodiment structure schematic view of the crosslinked polyethylene insulation flame-retardant power cable of the present application.

[0024] Figure 2 It is an enlarged schematic view of the structure at A of Figure 1

[0025] Figure 3 It is​Figure 1 A schematic diagram of the conductor and inner supporting tube structure;

[0026] Figure 4 for Figure 1 Schematic diagram of the internal support tube structure;

[0027] Figure 5 This is a schematic diagram of an embodiment of the cross-linked polyethylene insulated flame-retardant power cable production equipment of the present invention;

[0028] Figure 6 for Figure 5 Another perspective structural diagram.

[0029] In the figure: 1 Outer sheath, 2 Conductor, 3 Dividing cavity, 4 Elastic partition, 5 Tube body, 6 Binding strap, 7 Expanded graphite filler, 8 Expanded graphite strap, 9 Inner support tube, 10 Conductor guide, 11 Conductor limiting component, 12 Horn shell, 13 Support, 14 Drive mechanism, 15 Rotating ring, 16 Expanded graphite strap support frame. Detailed Implementation

[0030] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0031] Example 1: Please refer to Figures 1-4 This embodiment discloses a cross-linked polyethylene insulated flame-retardant power cable, including a deformable inner support tube 9. The outer periphery of the inner support tube 9 is recessed inward to form three receiving grooves. The length direction of the receiving grooves is parallel to the axial direction of the inner support tube 9. The three receiving grooves are arranged at equal angles around the axis of the inner support tube 9 on the outer periphery of the inner support tube 9. Each receiving groove is provided with a conductor 2 that fits against the inner wall of the receiving groove. The inner support tube 9 is provided with a deformable tube body 5. The conductor 2 makes the inner support tube 9 abut against the tube body 5. The inner support tube 9 is wrapped with an expanded graphite wrapping tape 8. The expanded graphite wrapping tape 8 is wrapped with a binding wrapping tape 6. The binding wrapping tape 6 is provided with an outer sheath 1 made of flame-retardant cross-linked polyethylene material.

[0032] The tube body 5 is made of a deformable material: the tube body 5 is made of elastic rubber or elastic plastic, or the tube body 5 is made of soft plastic and both ends of the tube body 5 are closed.

[0033] The inner support tube 9 is filled with fluorinated liquid. The conductor 2 squeezes the tube body 5 through the inner support tube 9. When the conductor 2 is subjected to a force pointing towards the tube body 5, the conductor 2 squeezes the tube body 5, causing the deformation of the tube body 5 to increase. When the force on the conductor 2 pointing towards the tube body 5 decreases, the deformation of the tube body 5 decreases.

[0034] Further, the ratio of the outer diameter of the tube 5 to the outer diameter of the conductor 2 is 1.0:2.0-6.1, and the ratio of the distance between the two edges of the receiving groove on the inner support tube 9 to the diameter of the conductor 2 is 1.0:5.0-20.0.

[0035] Further, the binding tape 6 is a glass fiber tape, an aluminum tape or a copper tape.

[0036] Further, the conductor 2 comprises a plurality of wires, and the wires are provided with a mica tape, a rubber insulation layer or a plastic insulation layer.

[0037] Further, the boiling point of the fluorinated liquid is 61-150℃.

[0038] Further, the expanded graphite tape 8 comprises a fiber cloth provided with expanded graphite, and the fiber cloth is a glass fiber cloth or an insulating rubber cloth.

[0039] The working process and principle of the embodiment are as follows:

[0040] When the crosslinked polyethylene insulation flame-retardant power cable is burned by fire, the outer sheath 1 transmits heat to the expanded graphite tape 8 through the binding tape 6, the temperature on the expanded graphite tape 8 exceeds the initial expansion temperature of the expanded graphite, the binding tape 6 makes the expanded graphite on the expanded graphite tape 8 expand inward, the expanded expanded graphite gives the conductor 2 an action force directed to the tube 5, the conductor 2 extrudes the tube 5 to make the deformation amount of the tube 5 larger, the expanded expanded graphite slows down the transmission speed of heat from the binding tape 6 to the conductor 2, and the fluorinated liquid in the inner support tube 9 evaporates to absorb heat, so that the temperature of the conductor 2 is maintained near the boiling point of the fluorinated liquid.

[0041] During the power transmission of the crosslinked polyethylene insulation flame-retardant power cable, part of the heat generated by the conductor 2 is transferred to the surrounding environment through the expanded graphite tape 8, the binding tape 6 and the outer sheath 1, and the other part of the heat generated by the conductor 2 is transmitted to the fluorinated liquid through the inner support tube 9, so that the temperature of the fluorinated liquid near the inner wall of the inner support tube 9 is increased, the inconsistent temperature of the fluorinated liquid in the inner cavity of the inner support tube 9 makes the fluorinated liquid flow, thereby realizing the temperature control of the conductor 2 and ensuring the reliability of the power transmission of the crosslinked polyethylene insulation flame-retardant power cable.

[0042] When the conductor 2 abnormally generates heat, the heat generated by the conductor 2 makes the fluorinated liquid in the inner cavity of the inner support tube 9 evaporate, the fluorinated liquid vapor generated by the evaporation gradually liquefies during the movement in the inner support tube 9, and the heat dissipation speed of the conductor 2 is fast and the heat dissipation effect is good.

[0043] The evaporation of the fluorinated liquid in the inner supporting tube 9 generates fluorinated liquid vapor, which increases the hydraulic pressure in the inner supporting tube 9. The hydraulic pressure in the inner supporting tube 9 deforms the tube body 5, and the volume of the tube body 5 decreases. The hydraulic pressure in the inner supporting tube 9 is maintained within a set range, thereby avoiding the rupture of the inner supporting tube 9 due to excessive hydraulic pressure in the inner supporting tube 9.

[0044] Preferably, the maximum height difference of the crosslinked polyethylene insulated flame-retardant power cable after installation is less than 3.0 m. The upward bending position of the crosslinked polyethylene insulated flame-retardant power cable is located near the fire sprinkler. After a fire occurs, the fluorinated liquid vapor in the inner cavity of the inner supporting tube 9 accumulates at the upward bending position of the crosslinked polyethylene insulated flame-retardant power cable. The water sprayed by the fire sprinkler cools the upward bending position of the crosslinked polyethylene insulated flame-retardant power cable. The fluorinated liquid vapor at the upward bending position condenses into fluorinated liquid, which slows down the increase in hydraulic pressure in the inner supporting tube 9, thereby avoiding the rupture of the inner supporting tube 9 due to excessive hydraulic pressure in the inner supporting tube 9.

[0045] Preferably, the flame-retardant crosslinked polyethylene material is crosslinked polyethylene with added aluminum hydroxide powder or magnesium hydroxide powder, or the flame-retardant crosslinked polyethylene material is added with a bromine-based or chlorine-based flame retardant.

[0046] Example Two: As shown in Figures 1-4 , the present embodiment discloses a crosslinked polyethylene insulated flame-retardant power cable, which has a structure substantially the same as that of Example One. The difference lies in that the inner supporting tube 9 of the present embodiment is made of soft plastic or soft rubber. The inner wall of the accommodating groove of the inner supporting tube 9 and the conductor 2 are tightly attached, which facilitates the transfer of heat from the conductor 2 to the fluorinated liquid in the inner cavity of the inner supporting tube 9.

[0047] Example Three: As shown in Figure 1 , Figure 2 , and Figure 4 , the present embodiment discloses a crosslinked polyethylene insulated flame-retardant power cable, which has a structure substantially the same as that of Example Two. The difference lies in that the outer periphery of the tube body 5 of the present embodiment is fixed with three elastic partitions 4 at equal angles around the axis. The elastic partitions 4 are made of elastic rubber or elastic silica gel. An elastic partition 4 is inserted between any two adjacent conductors 2.

[0048] The working process and principle of the present embodiment are as follows:

[0049] When the crosslinked polyethylene insulated flame-retardant power cable is placed horizontally, the elastic partitions 4 divide the conductors 2, allowing the three conductors 2 to move towards the tube body 5.

[0050] The inner supporting tube 9 and the fluorinated liquid in the inner supporting tube 9 allow the conductors 2 to relatively dislocate during the bending process. The minimum bending radius of the crosslinked polyethylene insulated flame-retardant power cable is small, which improves the use range of the crosslinked polyethylene insulated flame-retardant power cable.

[0051] Example Four: As shown inFigures 1-4 As shown in the figure, the embodiment discloses a cross-linked polyethylene insulation flame-retardant power cable, which has substantially the same structure as that of the first embodiment, but differs from the first embodiment in that the inner supporting tube 9 is made of elastic plastic or elastic rubber.

[0052] The working process and principle of the embodiment are as follows:

[0053] The installation of the conductor 2 in the accommodating groove of the inner supporting tube 9 is convenient.

[0054] Embodiment five: Figure 1 , Figure 3 and Figure 4 As shown in the figure, the embodiment discloses a cross-linked polyethylene insulation flame-retardant power cable, which has substantially the same structure as that of the first embodiment, but differs from the first embodiment in that the inner wall of the inner supporting tube 9 and the outer periphery of the tube body 5 are bonded or ultrasonic welded, and the inner cavity of the inner supporting tube 9 is divided into three divided cavities.

[0055] The working process and principle of the embodiment are as follows:

[0056] The staff member assembles the three divided cavities into a circulating heat dissipation flow channel or assembles any two divided cavities into a circulating heat dissipation flow channel, and the staff member connects the external liquid pump, the external fin liquid radiator and the heat dissipation flow channel, so that the liquid pump makes the fluorinated liquid circulate between the inner supporting tube 9 and the fin liquid radiator, the fin liquid radiator dissipates heat of the fluorinated liquid, and the maximum current carrying capacity of the cross-linked polyethylene insulation flame-retardant power cable is improved.

[0057] The fixed connection of the inner wall of the inner supporting tube 9 and the outer periphery of the tube body 5 fixes the relative positions of the three conductors 2, and the position of the tube body 5 between the three conductors 2 is fixed.

[0058] Embodiment six: Figures 1-4 As shown in the figure, the embodiment discloses a cross-linked polyethylene insulation flame-retardant power cable, which has substantially the same structure as that of the first embodiment, but differs from the first embodiment in that the two side edges of the accommodating groove on the inner supporting tube 9 are filled with the expanded graphite filler 7.

[0059] The working process and principle of the embodiment are as follows:

[0060] When a fire occurs, the expanded graphite filler 7 increases the extrusion force of the conductor 2 on the tube body 5, and the fireproof performance of the cross-linked polyethylene insulation flame-retardant power cable is improved.

[0061] Embodiment seven: Figure 5 and Figure 6As shown, the embodiment discloses a cross-linked polyethylene insulation flame-retardant power cable production equipment for producing the cross-linked polyethylene insulation flame-retardant power cable of embodiment two or embodiment three, which comprises a horn shell 12, the horn shell 12 has a large end and a small end, three conductor guides 10 are arranged at equal angles on the inner wall of the horn shell 12 close to the large end, the conductor guide 10 is an arc-shaped plate fixed on the inner wall of the horn shell 12 or an arc-shaped groove opened on the inner wall of the horn shell 12, three conductor limiters 11 are fixed at equal angles on the inner wall of the horn shell 12, the length direction of the conductor limiter 11 is parallel to the axial direction of the horn shell 12, one end of the conductor limiter 11 is close to the small end of the horn shell 12, the other end of the conductor limiter 11 is close to one of the conductor guides 10, a support 13 is fixed on the outer side of the horn shell 12, a rotating ring 15 is installed on the support 13 through a bearing or a rotating pin sleeve, an expanded graphite tape support frame 16 is fixedly installed on the rotating ring 15, and a driving mechanism 14 for driving the rotating ring 15 to rotate is installed on the support 13.

[0062] The working process and principle of the embodiment are as follows:

[0063] The worker fixes the horn shell 12 on the external support part, and the large end of the horn shell 12 faces upward, the expanded graphite tape support frame 16 is installed on the tray with the expanded graphite tape 8 wound thereon, the pipe body 5 is centrally inserted into the inner support tube 9, the worker inserts the inner support tube 9 and the three conductors 2 downward through the horn shell 12 from the large end of the horn shell 12, and one conductor 2 is slidably attached to each conductor guide 10, the inner support tube 9 is located between the three conductors 2, the lower end of the inner support tube 9 is closed, the inner support tube 9 is filled with fluorinated liquid, one end of the expanded graphite tape 8 is fixed on the inner support tube 9, the external pulling equipment drives the inner support tube 9 and the three conductors 2 to move downward synchronously, the worker drives the driving mechanism 14 to drive the rotating ring 15 and the tray to rotate around the horn shell 12, the expanded graphite tape 8 is wound on the inner support tube 9 away from the small end of the horn shell 12, then the worker drives the external wrapping machine to wrap the restraint tape 6 outside the expanded graphite tape 8, and the worker drives the external extruder to form the outer sheath 1 of the flame-retardant cross-linked polyethylene material outside the expanded graphite tape 8.

[0064] During the downward movement of the conductor 2 in the horn shell 12, the conductor 2 extrudes the containing groove on the inner support tube 9, the conductor limiter 11 makes the distance between the conductor 2 and the pipe body 5 smaller and smaller, and the distance between the two sides of the containing groove gradually becomes smaller, and the conductor 2 is fixed on the inner support tube 9 conveniently.

[0065] Further, the inner diameter of the inner wall of the horn shell 12 close to the small end of the horn shell 12 is equal to the outer diameter after the three containing grooves are formed by inwardly recessing the outer periphery of the inner support tube 9, and the distance between the two sides of the containing groove on the inner support tube 9 is greater than the width of the conductor limiter 11.

[0066] Further, the conductor limiting piece 11 is an arc-shaped rod, and an arc-shaped slot is formed in the inner side of the arc-shaped rod along the length direction of the arc-shaped rod.

[0067] Embodiment Eight: as shown in Figure 5 and Figure 6 The embodiment discloses a kind of crosslinked polyethylene insulation flame-retardant power cable production equipment, its structure is substantially same with the structure of embodiment seven, different is that, the rotating ring 15 of this embodiment is outer gear ring, drive mechanism 14 is motor, hydraulic motor or pneumatic motor, gear is fixed on the power output shaft of drive mechanism 14, and gear and outer gear ring are engaged.

[0068] The drive mechanism 14 used in the application is a common power source in the prior art, its working mode, structure and supporting equipment are all known technologies, and will not be repeated here.

[0069] The working process and principle of the embodiment are as follows:

[0070] Staff makes drive mechanism 14 drive tray wound with expanded graphite tape 8 to rotate horn shell 12 by gear and outer gear ring.

[0071] Although the embodiments of the present application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present application.

Claims

1. A cross-linked polyethylene insulated flame-retardant power cable, characterized in that: The device includes a deformable inner support tube (9), the outer periphery of which is recessed inward to form three receiving grooves. The three receiving grooves are arranged at equal angles around the axis of the inner support tube (9) on the outer periphery of the inner support tube (9). Each receiving groove is provided with a conductor (2) that fits against the inner wall of the receiving groove. The inner support tube (9) is provided with a deformable tube body (5). The inner support tube (9) is wrapped with an expanded graphite wrapping tape (8). The expanded graphite wrapping tape (8) is wrapped with a binding tape (6). The binding tape (6) is provided with an outer sheath (1) made of flame-retardant cross-linked polyethylene material. Wherein, the tube body (5) is made of elastic material and / or the two ends of the tube body (5) are closed, the inner support tube (9) is filled with fluorinated liquid, and the conductor (2) squeezes the tube body (5) through the inner support tube (9). When the conductor (2) is subjected to a force pointing towards the tube (5), the conductor (2) squeezes the tube (5) and causes the deformation of the tube (5) to increase. When the force applied to the conductor (2) towards the tube (5) decreases, the deformation of the tube (5) decreases.

2. The cross-linked polyethylene insulated flame-retardant power cable according to claim 1, characterized in that: The inner support tube (9) is made of soft material.

3. The cross-linked polyethylene insulated flame-retardant power cable according to claim 1, characterized in that: Three elastic partitions (4) are fixed at equal angles around the outer periphery of the tube (5) and an elastic partition (4) is inserted between any two adjacent conductors (2).

4. The cross-linked polyethylene insulated flame-retardant power cable according to claim 1, characterized in that: The inner support tube (9) is made of elastic material.

5. The cross-linked polyethylene insulated flame-retardant power cable according to claim 1, characterized in that: The inner wall of the inner support tube (9) is fixedly connected to the outer periphery of the tube body (5), and the inner cavity of the inner support tube (9) is divided into three partitioned cavities.

6. The cross-linked polyethylene insulated flame-retardant power cable according to claim 1, characterized in that: The ratio of the outer diameter of the tube (5) to the outer diameter of the conductor (2) is 1.0:2.0-6.1, and the ratio of the distance between the two sides of the groove on the inner support tube (9) to the diameter of the conductor (2) is 1.0:5.0-20.

0.

7. The cross-linked polyethylene insulated flame-retardant power cable according to claim 1, characterized in that: The binding strap (6) is a glass fiber strap, an aluminum strap, or a copper strap.

8. The cross-linked polyethylene insulated flame-retardant power cable according to claim 1, characterized in that: The inner support tube (9) is filled with expanded graphite filler (7) between the two sides of the groove.

9. A production equipment for cross-linked polyethylene insulated flame-retardant power cables, used to produce the cross-linked polyethylene insulated flame-retardant power cables as described in claim 2 or 3, characterized in that: The device includes a horn shell (12), with three conductor guides (10) at equal angles near the large end of the inner wall of the horn shell (12), and three conductor limiting members (11) fixed at equal angles on the inner wall of the horn shell (12). The length direction of the conductor limiting members (11) is parallel to the axial direction of the horn shell (12). One end of the conductor limiting member (11) is close to the small end of the horn shell (12), and the other end of the conductor limiting member (11) is close to one of the conductor guides (10). A support (13) is fixed on the outer side of the horn shell (12), and a rotating ring (15) is installed on the support (13). An expanded graphite wrapping support frame (16) is installed on the rotating ring (15), and a drive mechanism (14) that drives the rotating ring (15) to rotate is installed on the support (13). In this case, the large end of the horn shell (12) faces upward, and a tray with expanded graphite wrapping tape (8) is installed on the expanded graphite wrapping tape support frame (16). The inner support tube (9) is inserted into the tube body (5) in the center. The inner support tube (9) and the three conductors (2) pass downward through the horn shell (12) from the large end of the horn shell (12). Each conductor guide (10) has a conductor (2) slidingly attached to it. The inner support tube (9) is located between the three conductors (2). The lower end of the inner support tube (9) is closed. The inner support tube (9) is filled with fluorinated liquid. One end of the expanded graphite wrapping tape (8) is fixed on the inner support tube (9). The inner support tube (9) and the three conductors (2) move downward synchronously. The driving mechanism (14) causes the rotating ring (15) to drive the tray to rotate. The expanded graphite wrapping tape (8) is wrapped around the inner support tube (9) away from the small end of the horn shell (12). Among them, the inner diameter of the inner wall of the horn shell (12) near the small end of the horn shell (12) is equal to the outer diameter of the inner support tube (9) after the three receiving grooves are formed by the inward indentation on the outer periphery. The distance between the two sides of the receiving groove on the inner support tube (9) is greater than the width of the conductor limiting member (11).

10. The cross-linked polyethylene insulated flame-retardant power cable production equipment according to claim 9, characterized in that: The rotating ring (15) is an external gear ring, and the driving mechanism (14) includes a motor with a gear fixed on it, and the gear meshes with the external gear ring.

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