Submarine cable with composite armored shielding layer

Abstract

The invention belongs to the technical field of submarine cables, and provides a submarine cable with a composite armored shielding layer. Comprising a cable core, an outer protective layer arranged outside the cable core and a composite armored shielding layer arranged between the cable core and the outer protective layer, the composite armored shielding layer comprises a base body, a conductive material and a magnetic conductive material, the conductive material and the magnetic conductive material are arranged in the base body, the conductive material is arranged on the side, close to the cable core, of the composite armored shielding layer, and the magnetic conductive material is arranged on the side, close to the cable core, of the composite armored shielding layer. The magnetic conductive material is arranged on the side, away from the cable core, of the composite armored shielding layer, the electric conductivity of the composite armored shielding layer in the direction away from the cable core is gradually reduced, and the magnetic permeability of the side, away from the cable core, of the composite armored shielding layer is larger than the magnetic permeability of the side, close to the cable core, of the composite armored shielding layer. While ensuring that the composite armored shielding layer has a good tensile effect, bidirectional shielding of an internal induced current and an external interference magnetic field is realized, and the loss of the submarine cable is greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of submarine cable, in particular to a submarine cable with a composite armored shielding layer. BACKGROUND

[0002] Submarine power cables usually have an armor layer composed of a plurality of armor wires. The armor wires are usually spirally wound on the single-core or multi-core cable of the submarine power cable, and the armor layer provides mechanical protection against lateral impact during cable installation and operation. In alternating current power cables, alternating magnetic fields can cause different types of losses in the armor layer. For example, in a plane parallel to the cable axis, a circular induced current is formed inside a single wire, and this loss is called eddy current loss.

[0003] The use of non-magnetic metal materials such as stainless steel or copper can greatly reduce eddy current loss, however, these alternative materials are much more expensive than low-carbon steel. In addition, the use of high-grade steel can increase the tensile strength of the armor, and high-grade steel is more expensive than low-carbon steel. There are also designs that provide a plating or resin coating outside the steel wire, but the gaps between the armor wires still cause technical problems such as water infiltration or structural instability. Some people also propose using non-metallic armor wires, such as aramid or para-aramid wires. This can increase the tensile strength of the armor and reduce weight, however, non-metallic armor wires lack the electromagnetic shielding effect of metal armor, and the cable still has significant losses.

[0004] On the other hand, the loss of metal armor is also affected by the insulation and conductive shielding effect of the cable. The dielectric constant and loss coefficient of the insulation layer directly affect the propagation speed and attenuation characteristics of electromagnetic waves in the shielding layer; if the shielding layer does not cooperate well with the insulation layer, electromagnetic waves may leak through air gaps or gaps, reducing the shielding effect and causing electromagnetic loss of the armor. For example, air gaps may exist between the insulation layers due to manufacturing processes or material properties, causing uneven electric field distribution, potential step between the semi-conductive shielding layer and the insulation layer, etc., which may cause partial discharge, thereby increasing cable loss and metal armor loss. SUMMARY

[0005] In order to solve the problems in the prior art, the present application studies the low-loss design of metal armor and provides a submarine cable with a composite armored shielding layer. The composite armored shielding layer has a gradually decreasing electrical conductivity in the direction away from the cable core. The magnetic permeability of the side of the composite armored shielding layer away from the cable core is greater than that of the side close to the cable core. While ensuring that the composite armored shielding layer has good tensile resistance, it realizes bidirectional shielding of internal induced current and external interference magnetic field, greatly reducing the loss of the submarine cable.

[0006] The embodiment of the present application provides a submarine cable with a composite armored shielding layer, which comprises a cable core, an outer sheath arranged outside the cable core, A composite armored shielding layer is further arranged between the cable core and the outer sheath, the composite armored shielding layer comprises a matrix, and a conductive material and a magnetic conductive material arranged in the matrix, the conductive material is arranged on a side of the composite armored shielding layer close to the cable core, and the magnetic conductive material is arranged on a side of the composite armored shielding layer away from the cable core. In the embodiment, the composite armored shielding layer has gradually decreasing conductivity in the direction away from the cable core. The magnetic conductive material is a non-conductive material, and the magnetic permeability of the side of the composite armored shielding layer away from the cable core is greater than that of the side of the composite armored shielding layer close to the cable core.

[0007] In some embodiments, the conductive material is a metal wire, and the metal wire comprises at least two layers.

[0008] In some embodiments, the materials of the metal wires of different layers are different, and the conductivity of the metal wires of different layers gradually decreases in the direction of the composite armored shielding layer away from the cable core.

[0009] In some embodiments, the materials of the metal wires of different layers are the same, and the diameter of the metal wire of an inner layer is greater than that of an adjacent metal wire of an outer layer.

[0010] In some embodiments, the conductive material is a braided layer, and the braided layer comprises at least two layers.

[0011] In some embodiments, the materials of the braided layers of different layers gradually decrease in conductivity in the direction of the composite armored shielding layer away from the cable core.

[0012] In some embodiments, the materials of the braided layers of different layers are the same, and the braiding density of the braided layers of different layers gradually decreases in the direction of the composite armored shielding layer away from the cable core.

[0013] In some embodiments, the conductive material is a conductive particle, and the filling proportion of the conductive particle gradually decreases in the direction of the composite armored shielding layer away from the cable core.

[0014] In some embodiments, the magnetic conductive material is a coating layer arranged on the surface of the composite armored shielding layer away from the cable core and having a certain thickness.

[0015] In some embodiments, the magnetic permeability of the composite armored shielding layer gradually decreases in the direction close to the cable core.

[0016] In some embodiments, the magnetic conductive material forms a magnetic conductive strip, and the magnetic conductive strip comprises at least two layers, and the number of the magnetic conductive strips gradually decreases in the direction of the composite armored shielding layer close to the cable core.

[0017] In some embodiments, the magnetically conductive material is magnetically conductive particles, and the proportion of the magnetically conductive particles gradually decreases in the direction away from the cable core.

[0018] In some embodiments, the magnetically conductive material is magnetically conductive particles, and the proportion of the magnetically conductive particles gradually decreases in the direction away from the cable core.

[0019] In some embodiments, the electrically conductive material is at least one of copper, aluminum, tin, nickel-based alloy and steel wire, and the magnetically conductive material is at least one of ferrite and permanent magnet.

[0020] Compared with the prior art, the application has the following beneficial effects: The composite armored shielding layer in the application sets the electrically conductive material on the side of the composite armored shielding layer close to the cable core and sets the magnetically conductive material on the side of the composite armored shielding layer away from the cable core, which not only has good tensile resistance but also has good shielding effect on the internal high-frequency magnetic field and good shielding effect on the external low-frequency magnetic field, realizes bidirectional shielding of the internal induced current and the external interference magnetic field, greatly reduces the loss of the submarine cable, and further reduces the temperature rise of the submarine cable. In addition, the design of gradually decreasing the electrical conductivity in the direction away from the cable core quickly introduces the induced current of the cable core into the composite armored shielding layer, avoids the generation of partial discharge, greatly improves the insulation performance of the submarine cable, and improves the stability and safety of the submarine cable operation.

[0021] To make the above-mentioned purposes, features and advantages of the application more obvious and easy to understand, the following preferred embodiments are described in detail below, and the accompanying drawings are described as follows. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the application, and therefore should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0023] Figure 1 Fig. 1 shows a structural schematic diagram of a submarine cable with a composite armored shielding layer according to the application; Figure 2 Fig. 2 shows a structural schematic diagram of a conductor core according to the application; Figure 3 Fig. 3 shows a structural schematic diagram of an insulation shielding system according to the application; Figure 4 Fig. 4 shows a structural schematic diagram of a conductor shielding structure in the insulation shielding system according to the application; Figure 5A structural diagram of an insulation shield in the insulation shield system of the present application is shown. Figure 6 Another structural diagram of an insulation shield in the insulation shield system of the present application is shown. Figure 7 A structural diagram of a composite armor shield layer in the present application is shown. Figure 8 Another structural diagram of a composite armor shield layer in the present application is shown. Figure 9 Another structural diagram of a composite armor shield layer in the present application is shown. Figure 10 Another structural diagram of a composite armor shield layer in the present application is shown. Figure 11 Another structural diagram of a composite armor shield layer in the present application is shown. Figure 12 Another structural diagram of a composite armor shield layer in the present application is shown. Figure 13 Another structural diagram of a composite armor shield layer in the present application is shown. Figure 14 Another structural diagram of a composite armor shield layer in the present application is shown. Figure 15 Another structural diagram of a submarine cable with a composite armor shield layer in the present application is shown. Figure 16 Another structural diagram of a submarine cable with a composite armor shield layer in the present application is shown.

[0024] In the figure: 1 - conductive core, 11 - conductor, 12 - conductor shield layer, 13 - insulation layer, 14 - insulation shield layer, 141 - matrix, 142 - first braided layer, 143 - second braided layer, 144 - third braided layer, 15 - metal sheath, 2 - filling strip, 3 - optical fiber unit, 4 - water-blocking layer, 5 - inner sheath, 6 - composite armor shield layer, 61 - matrix, 62 - magnetic conductive layer, 631 - first layer of metal wires, 632 - second layer of metal wires, 633 - third layer of metal wires, 64 - anti-stretching fiber, 65 - adhesive tape, 634 - fourth braided layer, 635 - fifth braided layer, 636 - sixth braided layer, 637 - conductive particles, 621 - first magnetic conductive strip, 622 - second magnetic conductive strip, 623 - magnetic conductive particles, 7 - outer sheath, 8 - reinforcing fiber layer, σ - electrical conductivity, μ - magnetic permeability. DETAILED DESCRIPTION

[0025] The term "comprising", "including", "containing", or "characterized by" in the specification of the present application is synonymous with "including" or "characterized by" and is inclusive or open-ended and does not exclude additional, unrecited elements or method steps.

[0026] It should be noted that similar reference numerals and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures. Furthermore, the terms "first," "second," "third," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance. The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0027] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0028] The present application will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0029] Example 1 This application provides a submarine cable with a composite armored shielding layer. As in Example 1, a submarine cable with a composite armored shielding layer, such as Figure 1 As shown, it includes, from the inside out, a cable core, a water-blocking layer 4, an inner sheath 5, a composite armored shielding layer 6, and an outer sheath 7.

[0030] The cable core includes at least one conductive core 1, such as Figures 2-3 As shown, the conductive core 1 includes a conductor 11, an insulation system, and a metal sheath 15. The insulation system includes a conductor shielding layer 12, an insulation layer 13, and an insulation shielding layer 14. In the insulation system, the conductor shielding layer 12 and the insulation shielding layer 14 have bidirectionally varying conductivity. Specifically, the conductivity σ of the conductor shielding layer 12 gradually decreases from the inside to the outside in the radial direction of the conductive core 1; the conductivity σ of the insulation shielding layer 14 gradually decreases from the outside to the inside in the radial direction of the conductive core 1. That is, the conductivity variations of the conductor shielding layer 12 and the insulation shielding layer 14 are in opposite directions.

[0031] Due to minute defects in the manufacturing process or abrupt changes in the conductivity of materials, micropores or charge concentrations may occur at the interface, leading to partial discharge. Preventing partial discharge at the interface between the insulated wire and the conductor shield 12 and the insulation shield 14 is one of the core objectives in the design, manufacturing, installation, and operation and maintenance of high-voltage submarine cables. By setting the conductor shield 12 to a structure with continuously decreasing conductivity σ, the interface between the conductor shield 12 and the insulation layer 13 is designed to prevent charge accumulation at the interface, significantly optimizing the electric field distribution between the conductor shield 12 and the insulation shield 14. Similarly, setting the insulation shield 14 to have a conductivity σ that gradually increases away from the insulation layer 13 optimizes the electric field between the insulation layer 13 and the insulation shield 14, and can quickly draw the charge at the interface of the insulation layer 13 into the insulation shield 14, preventing the occurrence of partial discharge.

[0032] In this embodiment, the conductive shielding layer includes a substrate 141 and conductive fillers distributed within the substrate 141. The substrate 141 is a resin material, and the conductive filler can be at least one of conductive carbon black, graphene, carbon nanotubes, silver nanowires, or copper nanowires. The filling ratio of the conductive filler decreases sequentially from the inside to the outside of the substrate 141 material, thereby achieving a gradual decrease in conductivity σ of the conductor shielding layer 12 from the inside to the outside in the radial direction of the conductive core 1. Figure 4 As shown, the arrows indicate the direction of conductivity. The increasing direction of the conductive filler in the substrate 141 continuously decreases, ensuring a continuous change in the potential of the conductor shielding layer 12, forming a smooth electric field transition, improving the shielding effect of the conductive shielding layer, and optimizing the interface performance with the insulating layer 13. Compared with the layer-by-layer wrapping structure of semiconducting shielding strips at different potentials, the conductor shielding layer 12 of this application does not have gaps caused by wrapping, avoiding partial discharge caused by wrapping gaps. Furthermore, the conductor shielding layer 12 of this application uses the substrate 141 as a medium and adopts an extrusion process, which ensures zero-gap contact between the conductor shielding layer 12 and the conductor 11, while ensuring the roundness of the conductive core 1.

[0033] In some embodiments, the filling ratio of the conductive filler gradually changes from 40% to 20% from the inside to the outside, so that the volume resistivity of the conductive shielding layer varies from 100 Ω / m to 1000 Ω / m in any range from the inside to the outside of the conductive core, and the difference between the ranges is at least 100 Ω / m. The conductivity is inversely proportional to the volume resistivity, thereby achieving a gradual decrease in conductivity σ of the conductor shielding layer 12 from the inside to the outside of the conductive core 1 in the radial direction.

[0034] In the embodiment, the insulating shielding layer 14 comprises a base 141, in which conductive fillers and inorganic particles (not shown in the figure) are added, the filling proportion of the conductive fillers in the base 141 increases gradually from inside to outside, and the filling proportion of the inorganic particles decreases gradually from inside to outside. The conductive fillers comprise at least one of conductive carbon black, graphene, carbon nanotube, nano silver wire or nano copper, and the inorganic fillers are, for example, alumina, boehmite, etc.

[0035] By adding the inorganic fillers, the distribution proportion of the conductive fillers in the base 141 can be controlled synchronously, and the addition of the inorganic fillers makes the conductor shielding layer 12 have higher thermal stability and mechanical strength, further strengthens the protection of the internal insulating layer 13, the conductor shielding layer 12 and the conductor 11, and improves the compression resistance of the conductive core 1.

[0036] Further, in some embodiments, the conductive fillers in the insulating shielding layer 14 are attached to fibers to form conductive fibers, the insulating shielding layer 14 comprises a plurality of layers of woven layers formed by the conductive fibers, the base 141 and the inorganic particles are filled between the pores of the woven layers, and the plurality of layers of woven layers formed by the conductive fibers is at least 2 layers. The conductive fillers can be controlled more easily by the woven layers of the conductive fibers, and the tensile resistance of the insulating shielding layer 14 is also increased.

[0037] Further, in some embodiments, the conductive fibers in each layer of the insulating shielding layer 14 have the same conductivity σ, but the weaving density of the woven layers gradually decreases from outside to inside. Since the conductive fibers have the same conductivity σ, the pore size of the woven layers is controlled by controlling the gradual change of the weaving density of the woven layers, the filling proportion of the base 141 material and the inorganic material is higher when the pore density of the woven layers is higher, and the corresponding conductivity σ is lower; and the filling proportion of the conductive fillers is higher when the pore density of the woven layers is lower, and the corresponding conductivity σ is higher.

[0038] Specifically, as shown in FIG. 2, the insulating shielding layer 14 comprises a base 141, inorganic particles and a plurality of layers of woven layers formed by conductive fibers, and the plurality of layers of woven layers is 3 layers, i.e., a first woven layer 142, a second woven layer 143 and a third woven layer 144 are sequentially arranged in the direction close to the insulating layer 13. The conductive fibers used in the first woven layer 142, the second woven layer 143 and the third woven layer 144 have the same conductivity σ, the density of the first woven layer 142 is greater than the density of the second woven layer 143, and the density of the second woven layer 143 is greater than the density of the third woven layer 144. By gradually reducing the weaving density of the woven layers from outside to inside, the conductivity σ of the insulating shielding layer 14 is lower when it is closer to the insulating layer 13, so as to reduce the potential step span between the insulating layer 13 and the insulating shielding layer 14, thereby avoiding the partial discharge between the insulating layer 13 and the insulating shielding layer 14. Figure 5 Further, in some embodiments, the conductive fillers in the insulating shielding layer 14 are attached to fibers to form conductive fibers, the insulating shielding layer 14 comprises a plurality of layers of woven layers formed by the conductive fibers, the base 141 and the inorganic particles are filled between the pores of the woven layers, and the plurality of layers of woven layers formed by the conductive fibers is at least 2 layers. The conductive fillers can be controlled more easily by the woven layers of the conductive fibers, and the tensile resistance of the insulating shielding layer 14 is also increased.

[0037] Further, in some embodiments, the conductive fillers in the insulating shielding layer 14 are attached to fibers to form conductive fibers, the insulating shielding layer 14 comprises a plurality of layers of woven layers formed by the conductive fibers, the base 141 and the inorganic particles are filled between the pores of the woven layers, and the plurality of layers of woven layers formed by the conductive fibers is at least 2 layers. The conductive fillers can be controlled more easily by the woven layers of the conductive fibers, and the tensile resistance of the insulating shielding layer 14 is also increased.

[0038] Specifically, as shown in FIG. 2, the insulating shielding layer 14 comprises a base 141, inorganic particles and a plurality of layers of woven layers formed by conductive fibers, and the plurality of layers of woven layers is 3 layers, i.e., a first woven layer 142, a second woven layer 143 and a third woven layer 144 are sequentially arranged in the direction close to the insulating layer 13. The conductive fibers used in the first woven layer 142, the second woven layer 143 and the third woven layer 144 have the same conductivity σ, the density of the first woven layer 142 is greater than the density of the second woven layer 143, and the density of the second woven layer 143 is greater than the density of the third woven layer 144. By gradually reducing the weaving density of the woven layers from outside to inside, the conductivity σ of the insulating shielding layer 14 is lower when it is closer to the insulating layer 13, so as to reduce the potential step span between the insulating layer 13 and the insulating shielding layer 14, thereby avoiding the partial discharge between the insulating layer 13 and the insulating shielding layer 14.

[0039] Further, in some embodiments, the conductive fibers in each layer of the insulating shielding layer 14 have the same weaving density, but the conductivity σ of the conductive fibers in each weaving layer gradually decreases in the direction close to the cable core. As shown in FIG. 2, the insulating shielding layer 14 includes a base 141, inorganic particles, and multiple weaving layers formed by conductive fibers, and the weaving layers are three layers, i.e., a first weaving layer 142, a second weaving layer 143, and a third weaving layer 144 arranged in the direction close to the insulating layer 13 in sequence. The weaving densities of the first weaving layer 142, the second weaving layer 143, and the third weaving layer 144 are the same, the conductivity σ of the conductive fibers used in the first weaving layer 142 is greater than the conductivity σ of the conductive fibers used in the second weaving layer 143, and the conductivity σ of the conductive fibers used in the second weaving layer 143 is greater than the conductivity σ of the conductive fibers used in the third weaving layer 144. Figure 6 By selecting the conductive fibers with different concentrations of conductive fillers, the conductivity σ of each layer of the weaving layer formed by the conductive fibers is controlled, so as to control the potential gradient of the insulating shielding layer 14. At the same time, since the weaving densities of the weaving layers are the same, only different conductive fibers need to be arranged in different layers, so as to reduce the complexity of the production process.

[0040] In some embodiments, the conductivity σ of the conductive fibers in each weaving layer gradually decreases in the direction close to the cable core, and at the same time, the weaving density of the weaving layer decreases to meet the requirement of the conductivity σ gradient.

[0041] In some embodiments, the conductivity σ of the conductive fibers on the side of the conductor shielding layer 12 away from the conductor 11 is less than the conductivity σ of the conductive fibers on the side of the insulating shielding layer 14 away from the conductor 11. The trend of continuous attenuation of the electric field from the conductive body shielding layer to the metal sheath 15 is ensured, the electric field on the outside is quickly introduced into the insulating layer 13, at the same time, the penetration of the grounding current of the metal sheath 15 through the insulating shielding layer 14 is prevented, and the eddy current loss is reduced. The conductivity is inversely proportional to the volume resistivity, and in some embodiments, the volume resistivity of the insulating shielding layer 14 changes from any interval of 100 Ω / m-500 Ω / m in the direction from the outside to the inside of the conductive core, and the difference of the interval is at least 100 Ω / m.

[0042]

[0043] ​Specifically, in some embodiments, the volume resistivity of the conductor shielding layer 12 in the gradual change interval in the direction from the inside to the outside of the cable core is 400 Ω / m-500 Ω / m, and the volume resistivity of the insulation shielding layer 14 in the gradual change interval in the direction from the outside to the inside of the cable core can be 300 Ω / m-400 Ω / m. In some embodiments, if the volume resistivity of the conductor shielding layer 12 in the gradual change interval in the direction from the inside to the outside of the cable core is in any interval of 1000 Ω / m-600 Ω / m, then the volume resistivity of the insulation shielding layer 14 in the gradual change interval in the direction from the outside to the inside of the cable core can be in any interval of 100 Ω / m-500 Ω / m.

[0044] The base body 141 is a cross-linked polyethylene material.

[0045] The cable core further comprises filler strips 2 and optical fiber units 3, the filler strips 2 are arranged between adjacent conductive cores 1, and the optical fiber units 3 are arranged in the filler strips 2.

[0046] The composite armored shielding layer 6 is arranged between the inner sheath 5 and the outer sheath, and comprises a matrix 61 and conductive material and magnetic material arranged in the matrix 61, the conductive material is arranged on the side of the composite armored shielding layer 6 close to the cable core, and the magnetic material is arranged on the side of the composite armored shielding layer 6 away from the cable core; wherein the conductivity σ of the composite armored shielding layer 6 gradually decreases in the direction away from the cable core; the magnetic material is a non-conductive material, and the magnetic permeability μ of the side of the composite armored shielding layer 6 away from the cable core is greater than the magnetic permeability μ of the side of the composite armored shielding layer 6 close to the cable core.

[0047] The composite armored shielding layer 6, with the conductive material arranged on the side of the composite armored shielding layer 6 close to the cable core and the magnetic material arranged on the side of the composite armored shielding layer 6 away from the cable core, not only has good tensile properties and wear resistance, but also has good shielding effect on the internal high-frequency magnetic field and good shielding effect on the external low-frequency magnetic field, thereby achieving bidirectional shielding of the internal induced current and the external interference magnetic field and greatly reducing the loss of the submarine cable.

[0048] In some embodiments, the magnetic material is at least one of ferrite or a permanent magnet, and is a coating arranged on the side away from the cable core, the coating has a certain thickness and forms a magnetic layer 62. The magnetic layer 62 is on the outer surface of the composite armored shielding layer 6, and not only has good electromagnetic shielding function, but also has excellent corrosion resistance and wear resistance.

[0049] The conductive material is at least one of copper, aluminum, tin, nickel-based alloy and steel wire, and the magnetic material is at least one of ferrite or a permanent magnet.

[0050] In some embodiments, the conductive material forms metal wires, and the metal wires are arranged in at least two layers.

[0051] As shown in Figure 7 The composite armored shielding layer 6 includes a matrix 61, a plurality of layers of metal wires arranged in the matrix 61, and a magnetic conductive layer 62 located on the outer surface of the matrix 141. Specifically, the metal wires are 3 layers, and the first layer of metal wires 631, the second layer of metal wires 632, and the third layer of metal wires 633 are arranged in the direction away from the cable core in sequence. Each layer of metal wires is made of a material with different electrical conductivity σ, wherein the electrical conductivity σ of the first layer of metal wires 631 is greater than that of the second layer of metal wires 632, and the electrical conductivity σ of the second layer of metal wires 632 is greater than that of the third layer of metal wires 633. The design of gradually reducing the electrical conductivity σ in the direction away from the cable core quickly introduces the induced current of the cable core into the composite armored shielding layer 6, avoids the occurrence of partial discharge, greatly improves the insulation performance of the submarine cable, and improves the stability and safety of the submarine cable operation. In this embodiment, the diameters of the first layer of metal wires 631, the second layer of metal wires 632, and the third layer of metal wires 633 are the same, and in some other embodiments, the diameters of the first layer of metal wires 631, the second layer of metal wires 632, and the third layer of metal wires 633 decrease in sequence in the direction away from the cable core.

[0052] In some embodiments, the materials of the different layers of metal wires are the same, the diameter of the inner layer of metal wires is greater than that of the adjacent outer layer of metal wires, and the outer layer of metal wires is further provided with stretch-resistant fibers 64. As shown in Figure 8 The composite armored shielding layer 6 includes a matrix 61, a plurality of layers of metal wires arranged in the matrix 61, and a magnetic conductive layer 62 located on the outer surface of the matrix 141. Specifically, the metal wires are 2 layers, and the first layer of metal wires 631 and the second layer of metal wires 632 are arranged in the direction away from the cable core in sequence. The diameter of the first layer of metal wires 631 is greater than that of the second layer of metal wires 632. The second layer of metal wires 632 is further provided with stretch-resistant fibers 64, and preferably, the stretch-resistant fibers 64 are Kevlar fibers. By adjusting the diameters of the metal wires, the electrical conductivity σ of the inner and outer layers of metal wires is changed, and the greater the diameter, the higher the electrical conductivity σ. Further, by arranging the stretch-resistant fibers between the outer layers of metal wires, the electrical conductivity σ of the outer layers of metal wires is adjusted, the tensile strength of the armor is improved, and the weight of the submarine cable is reduced.

[0053] Further, adhesive bands 65 can be designed between each layer of metal wires, as shown in Figure 9 The adhesive bands 65 can apply radial force to the inner layer of metal wires to tightly arrange the inner layer of metal wires, so as to avoid dislocation during the twisting process with the outer layer of metal wires.

[0054] In some embodiments, the conductive material is a woven layer formed by conductive fibers, and the woven layer includes at least 2 layers.

[0055] Furthermore, in some embodiments, the conductivity σ of the materials of the different braided layers decreases in the direction away from the cable core in the composite armor shielding layer 6, and the braiding density of each braided layer can be the same or different. For example... Figure 10 As shown, the composite armor shielding layer 6 includes a fourth braided layer 634, a fifth braided layer 635, and a sixth braided layer 636. The conductivity σ of the fourth braided layer 634 is greater than that of the fifth braided layer 635, and the conductivity σ of the fifth braided layer 635 is greater than that of the sixth braided layer 636. In this embodiment, the braiding density of the fourth braided layer 634 and the fifth braided layer 635 is the same, both greater than that of the sixth braided layer 636. In other embodiments, the densities of the fourth braided layer 634, the fifth braided layer 635, and the sixth braided layer 636 can decrease sequentially. The potential gradient within the composite armor shielding layer 6 can be controlled simultaneously by the conductivity σ of the conductive fibers and the braiding density.

[0056] In some other embodiments, the different braided layers are made of the same material, and the braiding density of each braided layer in the composite armor shielding layer 6 gradually decreases in the direction away from the cable core. For example... Figure 11 As shown, the composite armor shielding layer includes a fourth braided layer 634 and a fifth braided layer 635. The conductive fibers used in the fourth braided layer 634 and the fifth braided layer 635 have the same conductivity σ, but the braiding density of the fourth braided layer 634 is greater than that of the fifth braided layer 635, thereby reducing the conductivity σ of the composite armor shielding layer 6 in the direction away from the cable core.

[0057] In some embodiments, the permeability μ of the composite armored shielding layer 6 gradually decreases in the direction near the cable core. Specifically, magnetically conductive material forms magnetic strips, which include at least two layers. The number of magnetic strips in the composite armored shielding layer 6 gradually decreases in the direction near the cable core, thereby causing the permeability μ of the composite armored shielding layer 6 to gradually decrease in the direction near the cable core.

[0058] In the direction near the cable core, the magnetic strips can be arranged alternately with at least one of the tensile fibers or conductive materials. For example, when the conductive material is metal wire, the magnetic strips near the cable core are arranged alternately with the metal wires away from the cable core, or the magnetic strips near the cable core are arranged alternately with the metal wires away from the cable core and the tensile fiber 64. As another example, when the conductive material is conductive particles 637, the magnetic strips near the cable core are embedded in the conductive particles 637.

[0059] like Figure 12As shown, the composite armored shielding layer 6 includes a matrix 61, first magnetic conductive strips, second magnetic conductive strips, a first layer of metal wires 631, and a second layer of metal wires 632. The number of the first magnetic conductive strips is greater than the number of the second magnetic conductive strips, and the number of the first layer of metal wires 631 is greater than the number of the second layer of metal wires 632. The second magnetic conductive strips are arranged at intervals from the second layer of metal wires 632. The interval number can also be selected according to electromagnetic shielding requirements. For example, in the case of more external interference, the interval number of the second magnetic conductive strips from the second layer of metal wires 632 is 1, that is, the number of the second layer of metal wires 632 is higher than the number of the second magnetic conductive strips. When the shielding of internal induced current is required to be strong, the interval number of the second layer of metal wires 632 is 2 or more, so that the number of the second layer of metal wires 632 is higher than the number of the second magnetic conductive strips.

[0060] In some other embodiments, when the number of layers of metal wires is 3, the second magnetic conductive strips of the composite armored shielding layer 6 can also be arranged at intervals from the third layer of metal wires 633 and the tensile-resistant fibers 64. In this embodiment, the electrical conductivity σ of each layer of metal wires can be the same or different, and the diameter of the metal wires can also gradually decrease in the direction away from the cable core of the composite armored shielding layer 6. Figure 13 As shown, the composite armored shielding layer 6 includes a matrix 61, and first magnetic conductive strips, second magnetic conductive strips, a first layer of metal wires 631, a second layer of metal wires 632, and a third layer of metal wires 633 wrapped in the matrix 61. The tensile-resistant fibers 64 are arranged at intervals between the second layer of metal wires 632. Specifically, one tensile-resistant fiber 64 is arranged every two second layer of metal wires 632, and one second magnetic conductive strip and one tensile-resistant fiber 64 are arranged at intervals between the third layer of metal wires 633. Through this arrangement, the electrical conductivity σ can be gradually decreased in the direction away from the cable core of the composite armored shielding layer 6, and the magnetic permeability μ can be gradually decreased in the direction close to the cable core of the composite armored shielding layer 6. The induced current and the induced magnetic field can be quickly guided into the composite armored shielding layer 6 to the greatest extent, and bidirectional shielding can be achieved.

[0061] In this embodiment, the materials of each layer of metal wires are the same, and the electrical conductivity σ is reduced by decreasing the diameter and number of the metal wires in the direction away from the cable core of the composite armored shielding layer 6. In some other embodiments, different metal materials can be used for each layer of metal wires, and the diameter and number of each layer of metal wires can be adjusted as needed.

[0062] In some embodiments, the conductive material is a conductive particle 637 formed of at least one of copper, aluminum, tin, and nickel-based alloy. The filling ratio of the conductive particles 637 gradually decreases in the direction away from the cable core of the composite armored shielding layer 6.

[0063] In some embodiments, the magnetic conductive material is formed into magnetic conductive particles 623 by any one of ferrite or permanent magnet, and the filling ratio of the magnetic conductive particles 623 gradually decreases in the direction away from the cable core, so that the magnetic permeability μ of the composite armor shielding layer 6 gradually decreases in the direction away from the cable core.

[0064] As shown in Figure 14 The composite armor shielding layer 6 includes conductive particles 637 and magnetic conductive particles 623, the filling ratio of the conductive particles 637 gradually decreases in the direction away from the cable core, the filling ratio of the magnetic conductive particles 623 gradually decreases in the direction away from the cable core, and tensile-resistant fibers 64 are further arranged at the mixing position of the conductive particles 637 and the magnetic conductive material, so as to increase the tensile strength of the composite shielding layer.

[0065] Further, a reinforcing fiber layer 8 can be further arranged outside the composite armor shielding layer 6, as shown in Figure 15 to further improve the strength of the submarine cable.

[0066] The matrix 61 is any one of epoxy resin or polyethylene.

[0067] The outer sheath 7 is made of high-density polyethylene or polyethylene.

[0068] In some embodiments, the submarine cable is a single-core structure, as shown in Figure 16 The optical fiber unit 3 is arranged at the center of the conductive core 1, so as to most effectively utilize the cross-sectional space of the cable, and the communication unit does not need to be separately arranged outside the cable core, so that the entire cable has smaller diameter, higher roundness and lighter weight.

[0069] The above has introduced the embodiments of the present application in detail, and the principle and implementation mode of the present application are described by applying specific examples; the above embodiment description is only used to help understand the method and core idea of the present application; meanwhile, according to the idea of the present application, the specific implementation mode and application range will be changed by the person skilled in the art, and the above description should not be understood as the limitation of the present application.

Claims

1. A submarine cable with a composite armored shielding layer, comprising a cable core and an outer sheath disposed outside the cable core, characterized in that, A composite armor shielding layer is also provided between the cable core and the outer sheath. The composite armor shielding layer includes a matrix, as well as a conductive material and a magnetic material disposed within the matrix. The conductive material is disposed on the side of the composite armor shielding layer closer to the cable core, and the magnetic material is disposed on the side of the composite armor shielding layer away from the cable core. The conductivity of the composite armored shielding layer gradually decreases in the direction away from the cable core. The magnetically conductive material is a non-conductive material, and the magnetic permeability of the composite armored shielding layer on the side away from the cable core is greater than that on the side closer to the cable core.

2. The submarine cable with a composite armored shielding layer according to claim 1, characterized in that, The conductive material is a metal wire, and the metal wire comprises at least two layers.

3. The submarine cable with a composite armored shielding layer according to claim 2, characterized in that, The different layers of metal wires are made of different materials, and the conductivity of the metal wires in different layers gradually decreases in the direction away from the cable core in the composite armor shielding layer.

4. The submarine cable with a composite armored shielding layer according to claim 2, characterized in that, The metal wires in different layers are made of the same material, and the diameter of the inner metal wire is larger than the diameter of the adjacent outer metal wire.

5. The submarine cable with a composite armored shielding layer according to claim 1, characterized in that, The conductive material is a braided layer, which comprises at least two layers.

6. The submarine cable with a composite armored shielding layer according to claim 5, characterized in that, The conductivity of the materials of the braided layers decreases in the direction away from the cable core in the composite armor shielding layer.

7. The submarine cable with a composite armored shielding layer according to claim 5, characterized in that, The braided layers of different layers are made of the same material, and the braiding density of the braided layers of different layers decreases in the direction away from the cable core in the composite armor shielding layer.

8. The submarine cable with a composite armored shielding layer according to claim 1, characterized in that, The conductive material consists of conductive particles, and the proportion of conductive particles gradually decreases in the composite armor shielding layer in the direction away from the cable core.

9. The submarine cable with a composite armored shielding layer according to claim 1, characterized in that, The magnetic conductive material is a coating of a certain thickness applied to the surface of the composite armored shielding layer on the side away from the cable core.

10. The submarine cable with a composite armored shielding layer according to claim 1, characterized in that, The magnetic permeability of the composite armored shielding layer gradually decreases towards the cable core.

11. The submarine cable with a composite armored shielding layer according to claim 10, characterized in that, The magnetic material forms magnetic strips, which consist of at least two layers. In the composite armored shielding layer, the number of magnetic strips gradually decreases in the direction close to the cable core.

12. The submarine cable with a composite armored shielding layer according to claim 11, characterized in that, In the composite armored shielding layer, the magnetic strips on the side near the cable core are mixed with at least one of conductive material or tensile fiber.

13. The submarine cable with a composite armored shielding layer according to claim 10, characterized in that, The magnetic material is magnetic particles, and the filling ratio of magnetic particles gradually decreases in the composite armored shielding layer in the direction close to the cable core.

14. The submarine cable with a composite armored shielding layer according to claim 1, characterized in that, The conductive material is at least one of copper, aluminum, tin, nickel-based alloys and steel wire, and the magnetic material is at least one of ferrite or permanent magnet.

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