A low voltage multi-core mineral insulated cable

Abstract

The present invention relates to the field of cable technology, and in particular to a low-voltage multi-core mineral insulated cable, comprising a plurality of main cable units, a ground wire unit and an optical fiber unit, wherein the main cable units are arranged around the left and right sides of the optical fiber unit, a first mineral insulation layer is extruded between and around the main cable unit and the optical fiber unit, a second mineral insulation layer is extruded around the first mineral insulation layer, the ground wire unit is coated between the first mineral insulation layer and the second mineral insulation layer, a sheath layer is coated around the second mineral insulation layer, and an outer protective layer is arranged on the outside of the sheath layer. The cable as a whole can be matched and applied to complex and harsh working conditions, and can realize the characteristic of easy bending in one direction during use, and has a large bending radius in other directions, which effectively reduces cable damage caused by random and excessive twisting during cable laying and prolongs its service life.

Description

Technical Field

[0001] The invention relates to the technical field of cables, in particular to a low-voltage multi-core mineral insulated cable. Background Art

[0002] Low-voltage mineral insulated cable is a special cable that uses minerals as insulating materials. It has the characteristics of high fire resistance, high temperature resistance and corrosion resistance. It is suitable for power transmission and control in various harsh environments and is widely used in industrial and civil buildings.

[0003] After searching, it is found that in the prior art, a flexible mineral insulated isolated fire-proof cable is disclosed in the patent document with patent publication number CN204667963U. From its main structure, it can be seen that it mainly includes a conductor group, the conductor group includes a conductor cable, the conductor group also includes a ceramic composite tape layer, a phlogopite tape layer, an aluminum tube layer, and a low-smoke halogen-free irradiation cross-linked material layer. The ceramic composite tape layer wraps the conductor cable, the phlogopite tape layer wraps the ceramic composite tape layer, the aluminum tube layer wraps the phlogopite tape layer, and the low-smoke halogen-free irradiation cross-linked material layer wraps the aluminum tube layer.

[0004] It can be seen from the cable structure in the above prior art that it mainly relies on the ceramic to improve its high temperature resistance and flame retardancy and enhance the service life of the cable. However, in actual use, it still has the following problems:

[0005] First, the above-mentioned cable conductor adopts a single-core structure, and its transmission capacity is limited during the power transmission process, and it is not suitable for use as an industrial power transmission condition.

[0006] Second, when the existing cable structure is used in harsh working conditions where frequent dragging and bending are required, the cable has poor resistance to bending damage, which can easily lead to a significant reduction in its service life.

[0007] Third, when used in response to existing complex power and signal transmission conditions, the cables in the existing technology cannot meet the usage requirements and cannot effectively complete the monitoring and real-time transmission of power signals.

[0008] In summary, it can be seen that the existing flexible mineral insulated isolated fire-resistant cables cannot achieve the expected purpose when used to meet the requirements of power transmission and monitoring under complex working conditions.

[0009] Based on this, the present invention optimizes and improves the problems existing in the prior art, and hereby proposes a low-voltage multi-core mineral insulated cable that can be used in complex and harsh working conditions to better solve the problems existing in the prior art. Summary of the invention

[0010] The present invention solves one of the above technical problems, and the technical solution adopted is: a low-voltage multi-core mineral insulated cable, comprising a plurality of main cable units, a ground wire unit and an optical fiber unit, each of the main cable units is distributed around the left and right sides of the optical fiber unit, the ground wire unit is arranged on the upper and lower sides of the optical fiber unit, a first mineral insulation layer is extruded between and around the main cable unit and the optical fiber unit, a second mineral insulation layer is extruded around the first mineral insulation layer, the ground wire unit is coated between the first mineral insulation layer and the second mineral insulation layer, a sheath layer is coated around the second mineral insulation layer, and an outer protective layer is arranged on the outside of the sheath layer.

[0011] In any of the above schemes, preferably, the cross-sectional profile of the optical fiber unit is a flat structure, the upper and lower side surfaces of the outer profile of the optical fiber unit are arranged parallel to each other, and the left and right end surfaces are arranged symmetrically and are both semicircular.

[0012] In any of the above schemes, it is preferred that the optical fiber unit includes a communication optical fiber cable and a monitoring optical fiber cable arranged horizontally at intervals, and the communication optical fiber cable and the monitoring optical fiber cable are both coated in a glass fiber reinforcement layer, an aramid yarn outer protective layer is wrapped around the periphery of the glass fiber reinforcement layer, and a metal braided layer is coated and wound around the periphery of the aramid yarn outer protective layer, and the inner and outer surfaces of the metal braided layer are sprayed with a flat asphalt layer composed of asphalt.

[0013] In any of the above schemes, preferably, the communication optical fiber cable comprises a single-mode communication optical fiber body, and a communication optical fiber inner shielding layer and a communication optical fiber outer shielding layer are sequentially extruded and molded on the periphery of the single-mode communication optical fiber body.

[0014] In any of the above schemes, preferably, the monitoring optical fiber cable comprises a single-mode monitoring optical fiber body, and a monitoring optical fiber inner shielding layer and a monitoring optical fiber outer shielding layer are sequentially extruded and molded on the periphery of the single-mode monitoring optical fiber body.

[0015] In any of the above schemes, it is preferred that the main cable unit includes a multi-core main conductor formed by twisting a plurality of copper wires, a main conductor insulation layer is extruded and coated on the periphery of the multi-core main conductor, a main conductor metal braided shielding layer is molded and coated on the periphery of the main conductor insulation layer, a main conductor sheath layer is molded and coated on the periphery of the main conductor metal braided shielding layer, and the periphery of the main conductor sheath layer is coated by the first mineral insulation layer.

[0016] In any of the above schemes, it is preferred that a glass fiber mixed braided layer is arranged between the main conductor sheath layer and the main conductor metal braided shielding layer, and the inner surface and the outer surface of the glass fiber mixed braided layer are both impregnated with asphalt and an asphalt impregnation layer is attached to the surface thereof; wherein the thickness of the asphalt impregnation layer is ≥0.3mm.

[0017] In any of the above solutions, preferably, the second mineral insulation layer, the jacket layer and the top and bottom of the outer protective layer are all curved in an arc shape toward the center side of the optical fiber unit.

[0018] The upper and lower parts of the outer surface of the cable are both arranged in an arc-shaped structure, which can ensure that the top center of the cable and the bottom center of the cable are both recessed along the length of the cable, which can effectively ensure the easy bending characteristics of the cable when bending in the up and down directions; in addition, the bottom adopts the raised structures on the left and right sides of the arc-shaped structure to support the entire cable structure, which can effectively ensure that the traction resistance is reduced when the cable is pulled. At the same time, when the left and right sides are in contact with the bottom ground or the inside of the laying pipeline at the same time, the stability of the entire cable can be guaranteed, the probability of twisting and twisting of the cable during traction is reduced, and the smoothness of pulling is guaranteed.

[0019] In any of the above schemes, it is preferred that the left and right sides of the second mineral insulation layer, the sheath layer and the outer protective layer all protrude outwards and form lateral marking portions.

[0020] In any of the above schemes, it is preferred that the interior of the second mineral insulation layer at the position of the lateral marking portion is coated with a ductile steel wire rope, and the outer periphery of the ductile steel wire rope is coated with an insulating sleeve.

[0021] In any of the above solutions, preferably, the ground wire unit includes two sector-shaped ground wire components respectively arranged in the second mineral insulation layer at the upper part and the lower part of the optical fiber unit.

[0022] In any of the above solutions, preferably, the arc bending directions of the two sector-shaped grounding cable members are consistent and the centers of the base circles where the arc segments of the two sector-shaped grounding cable members are located are collinearly arranged with the center point of the optical fiber unit.

[0023] In any of the above schemes, it is preferred that the sector-shaped grounding cable assembly includes a multi-core grounding conductor formed by twisting a plurality of copper wires, the outer contour of the multi-core grounding conductor is in a sector shape, a grounding conductor insulation layer is extruded on the periphery of the multi-core grounding conductor, a non-metallic shielding layer is wrapped around the outer surface of the grounding conductor insulation layer, and a grounding conductor sheath layer is extruded on the periphery of the non-metallic shielding layer.

[0024] In any of the above schemes, preferably, a grounding conductor graphite layer is provided between the grounding conductor sheath layer and the non-metallic shielding layer.

[0025] In any of the above schemes, preferably, a flat shielding layer is provided between the first mineral insulating layer and the second mineral insulating layer, and the flat shielding layer is formed by mixing metal wires and glass fibers in a ratio of 1:1.

[0026] In any of the above solutions, preferably, the inner surface of the flat shielding layer is fixedly embedded in the outer surface of the first mineral insulating layer, and the outer surface of the flat shielding layer is fixedly embedded in the inner surface of the second mineral insulating layer.

[0027] Compared with the prior art, the present invention has the following beneficial effects:

[0028] 1. The low-voltage multi-core mineral insulated cable designed in the present invention can be matched and applied to complex and harsh working conditions as a whole. During use, it can realize the characteristic of easy bending in one direction, and the bending radius in other directions is large, which effectively reduces the cable damage caused by random and excessive twisting during cable laying, and effectively prolongs its service life.

[0029] 2. In the cable of the present invention, arranging the communication optical fiber cable and the monitoring optical fiber cable at the center of the cable can effectively ensure that the entire cable structure protects the internal optical fiber when in use, and effectively avoids damage to the internal optical fiber caused by excessive bending of the cable. In addition, the entire cable adopts a dual-mode structure of communication optical fiber and monitoring optical fiber, which can effectively realize the transmission of demand signals and the monitoring of dynamic changes of signals during cable transmission, effectively improving the efficient monitoring and control of transmission signals during cable transmission.

[0030] 3. The two fan-shaped grounding cable components arranged from top to bottom in this cable can better achieve safety during the grounding process, effectively improve the heat dissipation effect of the cable during the entire grounding process, effectively reduce resistance, share current, effectively reduce the current load on a single fan-shaped grounding cable component, and reduce the overall grounding resistance; grounding with a lower grounding resistance can better and more effectively introduce leakage into the earth, improve the protection efficiency of the cable system, and achieve the purpose of quickly discharging static electricity.

[0031] 4. The lateral marking parts raised on the left and right sides of the cable in the present invention can intuitively display whether the current cable is twisted or rotated, thereby reducing the probability of cable damage caused by excessive twisting of the cable. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following is a brief introduction to the drawings required for the specific embodiments or the prior art description. In all the drawings, similar elements or components are generally identified by similar reference numerals. In the drawings, the elements or components are not necessarily drawn according to the actual scale.

[0033] Figure 1 The figure is a schematic diagram of the cross-sectional structure of the low-voltage multi-core mineral insulated cable of the present invention.

[0034] In the figure, 1, the first mineral insulation layer; 2, the second mineral insulation layer; 3, the sheath layer; 4, the outer protective layer; 5, the multi-core main conductor; 6, the main conductor insulation layer; 7, the main conductor metal braided shielding layer; 8, the glass fiber mixed braided layer; 9, the asphalt impregnation layer; 10, the tough steel wire rope; 11, the insulating sleeve; 12, the multi-core grounding conductor; 13, the grounding conductor insulation layer; 14, the non-metallic shielding layer; 15, the grounding conductor graphite layer; 16, the flat shielding layer; 17, the glass fiber reinforcement layer; 18, the aramid yarn outer protective layer; 19, the metal braided layer; 20, the single-mode communication optical fiber body; 21, the communication optical fiber inner shielding layer; 22, the communication optical fiber outer shielding layer; 23, the single-mode monitoring optical fiber body; 24, the monitoring optical fiber inner shielding layer; 25, the monitoring optical fiber outer shielding layer; 26, the flat asphalt layer; 27, the main conductor sheath layer; 28, the grounding conductor sheath layer; 29, the optical fiber sheath layer. DETAILED DESCRIPTION

[0035] The following is a detailed description of the embodiments of the technical solution of the present invention in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and are therefore only used as examples, and cannot be used to limit the scope of protection of the present invention. Figure 1 as shown in .

[0036] Embodiment 1: A low-voltage multi-core mineral insulated cable comprises a plurality of main cable units, ground wire units and optical fiber units, wherein the main cable units are arranged around the left and right sides of the optical fiber unit, the ground wire units are arranged on the upper and lower sides of the optical fiber unit, a first mineral insulation layer 1 is extruded between and around the main cable units and the optical fiber units, a second mineral insulation layer 2 is extruded around the first mineral insulation layer 1, the ground wire unit is coated between the first mineral insulation layer 1 and the second mineral insulation layer 2, a sheath layer 3 is coated around the second mineral insulation layer 2, and an outer protective layer 4 is arranged on the outside of the sheath layer 3.

[0037] When designing the structure of the low-voltage multi-core mineral insulated cable in the present invention, placing the optical fiber unit in the inner center can effectively reduce the damage caused by frequent bending under complex and harsh working conditions, effectively protect the internal optical fiber unit, and effectively extend its service life.

[0038] In addition, the surrounding main cable units form effective external protection for the internal optical fiber units. The multi-layer insulation of the first mineral insulation layer 1 and the second mineral insulation layer 2 can effectively improve the insulation and flame retardant effect of the entire cable and reduce the risk of burning and leakage of the cable.

[0039] In any of the above schemes, it is preferred that the main cable unit includes a multi-core main conductor 5 formed by twisting a plurality of copper wires, a main conductor insulation layer 6 is extruded and coated on the periphery of the multi-core main conductor 5, a main conductor metal braided shielding layer 7 is molded and coated on the periphery of the main conductor insulation layer 6, a main conductor sheath layer 27 is molded and coated on the periphery of the main conductor metal braided shielding layer 7, and the periphery of the main conductor sheath layer 27 is coated by the first mineral insulation layer 1.

[0040] The main cable unit is formed by twisting copper wires into a multi-core main conductor 5, which can effectively ensure the easy-bending property of the entire multi-core main conductor 5 when bending, and effectively reduce the difficulty of bending.

[0041] The main conductor metal braided shielding layer 7 designed in the present invention can effectively shield electromagnetic signal interference.

[0042] In any of the above schemes, it is preferred that a glass fiber mixed braided layer 8 is arranged between the main conductor sheath layer 27 and the main conductor metal braided shielding layer 7, and the inner surface and outer surface of the glass fiber mixed braided layer 8 are both impregnated with asphalt and an asphalt impregnation layer 9 is attached to its surface; wherein the thickness of the asphalt impregnation layer 9 is ≥0.3mm.

[0043] The glass fiber hybrid braided layer 8 arranged in the main cable unit can be combined with the main conductor metal braided shielding layer 7 to achieve secondary shielding for the multi-core main conductor 5, thereby improving the shielding effect; secondly, the glass fiber hybrid braided layer 8 can cooperate with the asphalt impregnation layer 9 and the main conductor insulation layer 6 under normal circumstances to achieve better anti-corrosion and waterproof effects, and prevent moisture from penetrating into the multi-core main conductor 5; in addition, when the temperature of the multi-core main conductor 5 rises, the main conductor metal braided shielding layer 7 can soften upon receiving the high temperature and play a self-lubricating role when the cable is bent by external force.

[0044] In any of the above schemes, it is preferred that the left and right sides of the second mineral insulation layer 2, the sheath layer 3 and the outer protective layer 4 are all protruded outwards to form lateral marking portions.

[0045] The raised lateral markings on the left and right sides of the cable can intuitively show whether the current cable is twisted or rotated.

[0046] In any of the above schemes, it is preferred that the second mineral insulation layer 2 at the position of the lateral marking portion is coated with a tough steel wire rope 10 , and the outer periphery of the tough steel wire rope 10 is coated with an insulating sleeve 11 .

[0047] By adding the toughness steel wire rope 10, the toughness strength of the left and right sides of the cable can be effectively enhanced, so that the cable has low difficulty in bending in the up and down directions during transmission, but great difficulty in bending in the left and right directions, thereby ensuring that the cable bending has directionality and that the cable will not be twisted at will during cable transmission, thereby reducing the probability of damage caused by excessive twisting of the cable during random pulling.

[0048] In any of the above solutions, preferably, the ground wire unit includes two sector-shaped ground wire components respectively arranged in the second mineral insulation layer 2 at the upper part and the lower part of the optical fiber unit.

[0049] The two symmetrical and spaced sector-shaped grounding cables in the grounding unit can further improve the reliability and safety of the entire cable, prevent single point failures and provide redundancy. It can prevent the entire cable system from losing protection due to the failure of one of the sector-shaped grounding cables. When one sector-shaped grounding cable is disconnected or damaged for some reason, the other can continue to provide the necessary grounding protection to ensure the safe operation of the system.

[0050] Secondly, it can effectively reduce resistance, share current, effectively reduce the current load on a single sector-shaped grounding cable, and reduce the overall grounding resistance; grounding with a lower grounding resistance can better and more effectively introduce leakage into the earth, improve the protection efficiency of the cable system, and achieve the purpose of quickly discharging static electricity.

[0051] When a problem is found in one of the sector ground cable components, it can be replaced in time without affecting the overall safety of the cable system.

[0052] In any of the above solutions, preferably, the arc bending directions of the two sector-shaped grounding cable members are consistent and the centers of the base circles where the arc segments of the two sector-shaped grounding cable members are located are collinearly arranged with the center point of the optical fiber unit.

[0053] The fan-shaped grounding cable components arranged at intervals above and below are bent toward the same side to effectively ensure the easy bending characteristics when bending in a single phase, effectively ensure the bending direction of the entire cable during the installation process, and avoid excessive twisting of the cable during laying due to random bending.

[0054] In any of the above schemes, it is preferred that the sector-shaped grounding cable assembly includes a multi-core grounding conductor 12 formed by twisting a plurality of copper wires, the outer contour of the multi-core grounding conductor 12 is sector-shaped, a grounding conductor insulation layer 13 is extruded on the periphery of the multi-core grounding conductor 12, a non-metallic shielding layer 14 is wrapped around the outer periphery of the grounding conductor insulation layer 13, and a grounding conductor sheath layer 28 is extruded on the periphery of the non-metallic shielding layer 14.

[0055] The entire fan-shaped grounding cable assembly adopts a flat design with a fan-shaped structure, which makes it easier to bend during installation and can better disperse the pressure when subjected to external force, thereby protecting the internal conductor from damage, improving the pressure resistance of the multi-core grounding conductor 12, and making it less likely to break or deform when subjected to heavy pressure, thereby extending its service life.

[0056] In addition, since the sector-shaped ground wire has a larger surface area, it can dissipate heat more effectively and prevent overheating; effective heat dissipation can also reduce the increase in resistance caused by increased temperature, thereby reducing power loss and improving the overall energy efficiency of the system.

[0057] In any of the above solutions, preferably, a grounding conductor graphite layer 15 is provided between the grounding conductor sheath layer 28 and the non-metallic shielding layer 14 .

[0058] In the present invention, by providing the grounding conductor graphite layer 15, static charges and lightning can be quickly conducted away during grounding, avoiding potential damage to equipment and personnel due to charge accumulation, and at the same time ensuring normal maintenance and operation and protecting personnel safety during cable facility maintenance, thereby improving the safety of the entire cable grounding. In addition, the grounding conductor graphite layer 15 and the multi-core grounding conductor 12 can ensure stable transmission of communication signals, avoid data errors and equipment failures, and prevent electromagnetic interference and radiation.

[0059] In any of the above solutions, preferably, a flat shielding layer 16 is provided between the first mineral insulating layer 1 and the second mineral insulating layer 2 , and the flat shielding layer 16 is formed by mixing metal wires and glass fibers in a ratio of 1:1.

[0060] The flat shielding layer 16 disposed between the first mineral insulating layer 1 and the second mineral insulating layer 2 can effectively shield the internal main cable unit and the optical fiber unit, and effectively prevent the influence of interference signals such as external electromagnetic signals on the safe transmission of the cable.

[0061] The mixed weaving of metal wire and glass fiber can not only ensure the stability of the overall mixed weaving structure, but also effectively ensure the shielding effect of the entire mixed weaving structure.

[0062] In any of the above solutions, preferably, the inner surface of the flat shielding layer 16 is fixedly embedded in the outer surface of the first mineral insulating layer 1 , and the outer surface of the flat shielding layer 16 is fixedly embedded in the inner surface of the second mineral insulating layer 2 .

[0063] The inner surface and the outer surface of the flat shielding layer 16 are both fixed by a fixed embedding method, which can effectively ensure the stability of the structure of the entire flat shielding layer 16 .

[0064] Embodiment 2: Compared with Embodiment 1, this embodiment is different in that it also includes the following technical features:

[0065] In any of the above schemes, preferably, the cross-sectional profile of the optical fiber unit is a flat structure, the upper and lower side surfaces of the outer profile of the optical fiber unit are arranged parallel to each other, and the left and right end surfaces are arranged symmetrically and are both semicircular.

[0066] The flat structure of the optical fiber unit can ensure that when it bends along with the cable, its bending performance is improved and its bending radius is reduced, and at the same time it can effectively protect the internal optical fiber.

[0067] In any of the above schemes, it is preferred that the optical fiber unit includes a communication optical fiber cable and a monitoring optical fiber cable arranged horizontally at intervals, and the communication optical fiber cable and the monitoring optical fiber cable are both coated in a glass fiber reinforcement layer 17, an aramid yarn outer protective layer 18 is wrapped around the periphery of the glass fiber reinforcement layer 17, a metal braided layer 19 is coated and wound around the periphery of the aramid yarn outer protective layer 18, an optical fiber sheath layer 29 is arranged around the periphery of the metal braided layer 19, and the inner and outer surfaces of the metal braided layer 19 are sprayed with a flat asphalt layer 26 composed of asphalt.

[0068] When protecting communication optical fiber cables and monitoring optical fiber cables, the optical fiber unit can achieve double shielding by relying on the cooperation of the glass fiber reinforcement layer 17 and the aramid yarn outer protective layer 18, effectively improving the signal anti-interference ability of the entire optical fiber unit during the transmission process.

[0069] In addition, the flat asphalt layer 26 arranged on the inner and outer surfaces of the metal braided layer 19 can ensure the waterproof performance of the interior, and effectively enhance the waterproof and protective performance of the metal braided layer 19. In addition, when the entire cable is elevated due to long-term operation, the flat asphalt layer 26 located at the metal braided layer 19 will be lubricated, thereby assisting self-lubrication.

[0070] In any of the above schemes, preferably, the communication optical fiber cable comprises a single-mode communication optical fiber body 20, and a communication optical fiber inner shielding layer 21 and a communication optical fiber outer shielding layer 22 are sequentially extruded on the periphery of the single-mode communication optical fiber body 20.

[0071] The communication optical fiber inner shielding layer 21 and the communication optical fiber outer shielding layer 22 cooperate to achieve double-layer shielding, thereby improving the shielding effect.

[0072] In any of the above schemes, preferably, the monitoring optical fiber cable comprises a single-mode monitoring optical fiber body 23 , and a monitoring optical fiber inner shielding layer 24 and a monitoring optical fiber outer shielding layer 25 are sequentially extruded on the periphery of the single-mode monitoring optical fiber body 23 .

[0073] The inner shielding layer 24 of the monitoring optical fiber and the outer shielding layer 25 of the monitoring optical fiber cooperate to realize double-layer shielding, thereby improving the shielding effect.

[0074] In any of the above schemes, preferably, the top and bottom of the second mineral insulation layer 2, the jacket layer 3 and the outer protective layer 4 are all curved in an arc shape toward the center side of the optical fiber unit.

[0075] The upper and lower parts of the outer surface of the cable are both arranged in an arc-shaped structure, which can ensure that the top center of the cable and the bottom center of the cable are both recessed along the length of the cable, which can effectively ensure the easy bending characteristics of the cable when bending in the up and down directions; in addition, the bottom adopts the raised structures on the left and right sides of the arc-shaped structure to support the entire cable structure, which can effectively ensure that the traction resistance is reduced when the cable is pulled. At the same time, when the left and right sides are in contact with the bottom ground or the inside of the laying pipeline at the same time, the stability of the entire cable can be guaranteed, the probability of twisting and twisting of the cable during traction is reduced, and the smoothness of pulling is guaranteed.

[0076] From the above, it can be seen that the low-voltage multi-core mineral insulated cable designed in the present invention can be matched and applied to complex and harsh working conditions as a whole. It can realize the characteristic of easy bending in one direction during use, and the bending radius in other directions is large, which effectively reduces the cable damage caused by random and excessive twisting during cable laying, and effectively extends its service life; arranging the communication optical fiber cable and the monitoring optical fiber cable at the center of the cable can effectively ensure that the entire cable structure protects the internal optical fiber during use, and effectively avoids the damage of the internal optical fiber caused by excessive bending of the cable. In addition, the entire cable adopts a dual-mode structure of communication optical fiber and monitoring optical fiber, which can effectively realize the transmission of the demand signal and the monitoring of the dynamic change of the signal during the cable transmission process, and effectively improve the efficient monitoring and control of the transmission signal during the cable transmission process; the two fan-shaped grounding cable components arranged from top to bottom in the cable can better realize the safety during the grounding process, effectively improve the heat dissipation effect of the cable during the entire grounding process, effectively reduce the resistance, share the current, effectively reduce the current load on the single fan-shaped grounding cable component, and reduce the overall grounding resistance; grounding with a lower grounding resistance can better and more effectively introduce leakage into the earth, improve the protection efficiency of the cable system, and achieve the purpose of rapid discharge of static electricity.

[0077] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can still be modified, or some or all of the technical features can be replaced by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention. For those skilled in the art, any replacement improvements or changes made to the implementation methods of the present invention fall within the protection scope of the present invention.

[0078] The matters not described in detail in the present invention are all known technologies to those skilled in the art.

Claims

1. A low voltage multi-core mineral insulated cable, characterized in that: The invention comprises a plurality of main cable units, a ground wire unit and an optical fiber unit, wherein the main cable units are arranged around and distributed on the left and right sides of the optical fiber unit, the ground wire unit is arranged on the upper and lower sides of the optical fiber unit, a first mineral insulation layer is extruded between and on the periphery of the main cable unit and the optical fiber unit, a second mineral insulation layer is extruded on the periphery of the first mineral insulation layer, the ground wire unit is coated between the first mineral insulation layer and the second mineral insulation layer, a sheath layer is coated on the periphery of the second mineral insulation layer, and an outer protective layer is arranged on the outer side of the sheath layer; The optical fiber unit comprises a communication optical fiber cable and a monitoring optical fiber cable arranged horizontally at intervals, wherein the communication optical fiber cable and the monitoring optical fiber cable are both coated and arranged in a glass fiber reinforcement layer, an aramid yarn outer protective layer is wrapped around the outer periphery of the glass fiber reinforcement layer, a metal braided layer is coated and wound around the outer periphery of the aramid yarn outer protective layer, an optical fiber sheath layer is arranged around the outer periphery of the metal braided layer, and the inner and outer surfaces of the metal braided layer are sprayed with a flat asphalt layer composed of asphalt; The left and right sides of the second mineral insulation layer, the sheath layer and the outer protective layer are all bulged outward to form a lateral marking portion; the inside of the second mineral insulation layer at the lateral marking portion is coated with a tough steel wire rope, and the outer periphery of the tough steel wire rope is coated with an insulating sleeve; The top and bottom of the second mineral insulation layer, the jacket layer and the outer protective layer are all curved toward the center of the optical fiber unit in an arc shape; A flat shielding layer is arranged between the first mineral insulating layer and the second mineral insulating layer. The flat shielding layer is formed by mixing metal wires and glass fibers in a ratio of 1:

1.

2. A low voltage multi-core mineral insulated cable according to claim 1, characterized in that: The main cable unit includes a multi-core main conductor formed by twisting a plurality of copper wires, a main conductor insulation layer is extruded around the periphery of the multi-core main conductor, a main conductor metal braided shielding layer is molded around the periphery of the main conductor insulation layer, a main conductor sheath layer is molded around the periphery of the main conductor metal braided shielding layer, and the periphery of the main conductor sheath layer is covered by the first mineral insulation layer.

3. A low voltage multi-core mineral insulated cable according to claim 2, characterized in that: The ground wire unit includes two sector-shaped ground wire components respectively arranged in the second mineral insulation layer at the upper part and the lower part of the optical fiber unit.

4. A low voltage multi-core mineral insulated cable according to claim 3, characterized in that: The arc bending directions of the two sector-shaped grounding cable members are consistent, and the centers of the base circles where the arc segments of the two sector-shaped grounding cable members are located are collinearly arranged with the center point of the optical fiber unit.

5. A low voltage multi-core mineral insulated cable according to claim 4, characterized in that: The sector-shaped grounding cable assembly includes a multi-core grounding conductor formed by twisting a plurality of copper wires, the outer contour of the multi-core grounding conductor is in a sector shape, a grounding conductor insulation layer is extruded on the periphery of the multi-core grounding conductor, a non-metallic shielding layer is wrapped around the outer surface of the grounding conductor insulation layer, and a grounding conductor sheath layer is extruded on the outer surface of the non-metallic shielding layer.

6. A low voltage multi-core mineral insulated cable according to claim 5, characterized in that: A grounding conductor graphite layer is arranged between the grounding conductor sheath layer and the non-metallic shielding layer.

7. A low voltage multi-core mineral insulated cable according to claim 6, characterized in that: The inner surface of the flat shielding layer is fixedly embedded in the outer surface of the first mineral insulating layer, and the outer surface of the flat shielding layer is fixedly embedded in the inner surface of the second mineral insulating layer.

Images