CN114974677A

CN114974677A - Submarine cable

Info

Publication number: CN114974677A
Application number: CN202210795084.7A
Authority: CN
Inventors: 王丽媛; 王海洋; 聂影; 王文超; 孙艳雨; 赵囿林; 张洪亮; 潘盼; 朱井华; 刘利刚
Original assignee: Zhongtian Technology Submarine Cable Co Ltd
Current assignee: Zhongtian Technology Submarine Cable Co Ltd
Priority date: 2022-07-07
Filing date: 2022-07-07
Publication date: 2022-08-30

Abstract

The invention provides a submarine cable. The submarine cable comprises: at least three power units; the filling unit comprises a first mounting cavity and a plurality of second mounting cavities, the central area of the filling unit is in the area range surrounded by the three power units, the first mounting cavity is located in the central area of the filling unit, the plurality of second mounting cavities are distributed at intervals along the circumferential direction of the first mounting cavity, and each second mounting cavity is internally provided with one power unit; and the optical fiber unit is installed in the first installation cavity, and the inner wall surface of the first installation cavity is attached to the outer wall surface of the optical fiber unit. The submarine cable provided by the invention can solve the problem that the optical fiber unit is easy to break in the production and construction circulation processes of the conventional submarine cable.

Description

Submarine cable

Technical Field

The invention relates to the technical field of ocean engineering, in particular to a submarine cable.

Background

With the gradual deep exploration of people on the ocean, the ocean works are more and more frequent, and the requirements on submarine cables are more and more strict. Conventional submarine cable includes single core submarine cable and three core submarine cable, and the optical core unit of three core submarine cable is placed in the outside clearance of three electric power sinle silks, adopts packing rope or filler strip to fill, but at submarine cable stranding armor production circulation process or construction laying circulation, dilatory in-process, the disconnected fibre of optical fiber unit takes place easily, leads to the interrupt of circuit operation, causes great economic loss.

Disclosure of Invention

The invention mainly aims to provide a submarine cable, which can solve the problem that an optical fiber unit is easy to break in the production and construction circulation processes of the conventional submarine cable.

In order to achieve the above object, according to an aspect of the present invention, there is provided a submarine cable comprising: at least three power units; the filling unit comprises a first mounting cavity and a plurality of second mounting cavities, the central area of the filling unit is in the area range surrounded by at least three power units, the first mounting cavity is located in the central area of the filling unit, the plurality of second mounting cavities are distributed at intervals along the circumferential direction of the first mounting cavity, and each second mounting cavity is internally provided with one power unit; and the optical fiber unit is installed in the first installation cavity, and the inner wall surface of the first installation cavity is attached to the outer wall surface of the optical fiber unit.

Furthermore, the filling unit comprises at least three filling subunits, the at least three power units and the at least three filling subunits are alternately arranged along the circumferential direction, each filling subunit comprises a splicing part, the splicing parts are located at one ends, close to the optical fiber units, of the filling subunits, the at least three splicing parts are connected in pairs, the inner peripheral sides of the at least three splicing parts are spliced to form a first installation cavity for accommodating the optical fiber units, and the inner wall surfaces of the first installation cavity are attached to the outer wall surfaces of the optical fiber units; and/or the central area of the filling unit is in the center of the area enclosed by the at least three power units, and the first mounting cavity is positioned in the center of the central area.

Furthermore, the splicing portion comprises a first arc-shaped face and splicing faces located at two ends of the first arc-shaped face, the splicing faces are step faces, the three splicing portions are connected in a pairwise mode through the step faces to form a step limiting structure, and the three first arc-shaped faces are spliced to form a first installation cavity.

Furthermore, the filling subunit also comprises a second arc-shaped surface and two third arc-shaped surfaces, the second arc-shaped surface is positioned on one side of the splicing part away from the first arc-shaped surface, the two third arc-shaped surfaces are positioned between the first arc-shaped surface and the second arc-shaped surface, and the two adjacent third arc-shaped surfaces are spliced on one side away from the optical fiber unit to form a second installation cavity.

Further, the projection of the first arc-shaped surface on the submarine cable cross section is a first arc line, the projection of the second arc-shaped surface on the submarine cable cross section is a second arc line, and the arc length L1 of the first arc line satisfies:

the arc length L2 of the second arc satisfies:

wherein H is the distance between the second arc-shaped surface and the central axis of the submarine cable, and d is the diameter of the optical fiber unit.

Further, the step face includes first ladder and second ladder, and first ladder is located the one side that the optical fiber unit is close to the step face, and the second ladder is located the one side that the optical fiber unit is kept away from to the step face, and the relation of the minimum distance h between the outer wall face of height h1, the height h2 of second ladder, the power pack of first ladder and the optical fiber unit satisfies: h is h1+ h 2.

Further, the relationship of the distance H between the second arc-shaped surface and the central axis of the submarine cable, the diameter D of the optical fiber unit and the diameter D of the power unit satisfies:

further, the maximum distance K1 between two first steps on the same splice satisfies:

the minimum distance K2 between the two second steps satisfies:

wherein d is the diameter of the optical fiber unit.

Furthermore, one side of the power unit close to the optical fiber unit is attached to the third arc-shaped surface.

Further, on the cross section of the submarine cable, the projection of the third arc-shaped surface is a third arc line, the projection of the power unit is a circle, the third arc line and the circle are gradually separated from the joint tail end point P along the direction far away from the optical fiber unit, the connecting line between the joint tail end point P and the center of the power unit is L3, the connecting line between the center point of the optical fiber unit and the center of the power unit is L4, the included angle between L3 and L4 is α, and the value range of α is 60 degrees or more and 90 degrees or less.

Further, submarine cable still includes the shielding layer, and power unit and packing subunit set up in the inside of shielding layer, and the second arcwall face is laminated mutually with the shielding layer, and one side that power unit kept away from the optical fiber unit is tangent in point Q with the shielding layer.

Furthermore, on the cross section of the submarine cable, a connecting line between one end of the second arc line and the center of the optical fiber unit is L5, a connecting line between the point Q and the center of the optical fiber unit is L6, an included angle between L5 and L6 is theta, and the value range of theta is more than or equal to 0 degree and less than or equal to 30 degrees.

By applying the technical scheme of the invention, the filling unit is arranged and comprises a first mounting cavity and a second mounting cavity, the first mounting cavity is positioned in the region range surrounded by the three power units, the optical fiber units are mounted in the first mounting cavity, so that the optical fiber units are positioned in the region range surrounded by the three power units, namely the optical fiber units are positioned in the center of the submarine cable, in the process of production and construction circulation, the force borne by the central region of the submarine cable is small, the deformation quantity is small, the three power units are distributed at intervals along the circumferential direction of the first mounting cavity, the three power units can extrude the filling unit in different directions, the inner wall of the first mounting cavity can be tightly attached to the outer wall surface of the optical fiber units, the optical fiber units are extruded and limited, the deformation of the optical fiber units in the radial direction is reduced, and the structural stability of the optical fiber units is ensured, avoiding fiber breakage in the production and construction circulation processes.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 shows an overall structural schematic view of a submarine cable according to an embodiment of the present invention;

fig. 2 shows a schematic view of a filling unit structure of a submarine cable according to an embodiment of the present invention;

fig. 3 shows a partial dimensional schematic view of a submarine cable according to an embodiment of the invention;

FIG. 4 shows a partial dimensional schematic view of a submarine cable according to an embodiment of the invention; and

fig. 5 shows a partial enlarged view at a in fig. 4.

Wherein the figures include the following reference numerals:

10. a power unit; 20. a filling unit; 21. a first mounting cavity; 22. a second mounting cavity; 23. a filler subunit; 24. a first arc-shaped surface; 25. splicing the surfaces; 26. a second arcuate surface; 27. a third arc-shaped surface; 30. an optical fiber unit; 40. a first step; 50. a second step; 60. and a shielding layer.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the embodiments with reference to the attached drawings.

Referring to fig. 1 and 2 in combination, the present invention provides a submarine cable comprising: at least three power units 10; the power unit comprises a filling unit 20, wherein the filling unit 20 comprises a first mounting cavity 21 and a plurality of second mounting cavities 22, the central area of the filling unit 20 is within the area range surrounded by three power units 10, the first mounting cavity 21 is located in the central area of the filling unit 20, the plurality of second mounting cavities 22 are arranged at intervals along the circumferential direction of the first mounting cavity 21, and one power unit 10 is mounted in each second mounting cavity 22; and an optical fiber unit 30, wherein the optical fiber unit 30 is installed in the first installation cavity 21, and the inner wall surface of the first installation cavity 21 is attached to the outer wall surface of the optical fiber unit 30.

In this embodiment, the first installation cavity 21 is located in the central area of the filling unit 20, and the central area of the filling unit 20 is within the area surrounded by the three power units 10, so that the position of the first installation cavity 21 can be ensured to be within the area surrounded by the three power units 10, and the optical fiber unit 30 is installed in the first installation cavity 21, so that the optical fiber unit 30 is within the area surrounded by the three power units 10, that is, the optical fiber unit 30 is located in the central area of the submarine cable, during the production and construction circulation, the force applied to the central area of the submarine cable is small, the deformation amount is small, and at least three power units 10 are arranged at intervals along the circumferential direction of the first installation cavity 21, and at least three power units 10 can extrude the filling unit 20 in different directions, so that the inner wall of the first installation cavity 21 can be tightly attached to the outer wall surface of the optical fiber unit 30, the optical fiber unit 30 is extruded to be limited, the deformation space of the optical fiber unit 30 is compressed, the deformation of the optical fiber unit 30 in the radial direction is reduced, the structural stability of the optical fiber unit 30 is guaranteed, and the fiber breakage in the production and construction circulation processes is avoided.

In one embodiment of the present invention, the filling unit 20 is a filling bar.

Referring to fig. 1 and 2 in combination, in an embodiment of the present invention, the filling unit 20 includes at least three filling subunits 23, the at least three power units 10 and the at least three filling subunits 23 are alternately arranged along a circumferential direction, each filling subunit 23 includes a splicing portion, the splicing portion is located at one end of the filling subunit 23 close to the optical fiber unit 30, the at least three splicing portions are connected in pairs, the at least three splicing portions are spliced at an inner circumferential side to form a first installation cavity 21 for accommodating the optical fiber unit 30, and an inner wall surface of the first installation cavity 21 is attached to an outer wall surface of the optical fiber unit 30.

In the present embodiment, the at least three filling subunits 23 and the at least three power units 10 are alternately arranged along the circumferential direction, and the filling subunits 23 space the at least three power units 10 apart from each other, so that the at least three power units 10 are uniformly arranged, the mass distribution of the submarine cable is more uniform, and the stability of the internal structure of the submarine cable is improved. The mode that connects through two liang of three at least splices forms first installation cavity 21 in the concatenation of splice, makes things convenient for optical fiber unit 30's installation, in addition, if certain filling subunit 23 among them takes place to damage or when warping comparatively seriously, can change this filling subunit 23 alone, need not to change whole filling unit 20 to reduce the waste of material, practice thrift the cost. In addition, the plurality of power units 10 are spaced apart from each other, so that the area of the region surrounded by the plurality of power units 10 is larger, and an installation space is provided for the filler unit 20 and the optical fiber unit 30.

In one embodiment of the present invention, the optical fiber unit 30 includes an optical fiber, the optical fiber is filled with a water-blocking fiber paste, the outer side of the optical fiber is covered with a stainless steel tube, and the number of cores of the optical fiber is 4-144.

In one embodiment of the invention, the central area of the filling unit 20 is in the center of the area enclosed by the three power units 10, and the first installation cavity 21 is located in the center of the central area, which coincides with the center of the submarine cable.

In the present embodiment, the first installation cavity 21 is located at the center of the central region, the optical fiber unit 30 is installed in the first installation cavity 21, and at this time, the optical fiber unit 30 is located at the central position of the submarine cable, and since the central position of the submarine cable is stressed the least and the deformation amount is the least, the external force applied to the optical fiber unit 30 is the least, and the deformation amount of the optical fiber unit 30 in the radial direction is the least, which can prevent the submarine cable from breaking during the production and construction circulation process, thereby improving the service life of the submarine cable.

Referring to fig. 1 and 2 in combination, in an embodiment of the present invention, the splicing portion includes a first arc-shaped surface 24 and splicing surfaces 25 located at two ends of the first arc-shaped surface 24, the splicing surfaces 25 are step surfaces, the three splicing portions are connected in pairs through the step surfaces to form a step limiting structure, and the three first arc-shaped surfaces 24 are spliced to form the first mounting cavity 21.

Through the arrangement, the step surfaces of the three splicing parts are connected in pairs to form a step limiting structure, so that the three filling subunits 23 can be prevented from moving in the construction and circulation process, and the structural stability of the filling units 20 is further ensured. Three first arcwall face 24 splices and forms first installation cavity 21, and optical fiber unit 30 is installed in first installation cavity 21, and optical fiber unit 30's outer wall and first arcwall face 24 laminate mutually, can carry on spacingly and protect optical fiber unit 30, reduce the deformation of optical fiber unit 30 at the construction circulation in-process, prevent that optical fiber unit 30 from taking place absolutely fine because of the too big emergence of the external force that receives.

Referring to fig. 1 and 2 in combination, in an embodiment of the present invention, the filling subunit 23 further includes a second arc-shaped surface 26 and two third arc-shaped surfaces 27, the second arc-shaped surface 26 is located on a side of the splice portion away from the first arc-shaped surface 24, the two third arc-shaped surfaces 27 are located between the first arc-shaped surface 24 and the second arc-shaped surface 26, and two adjacent third arc-shaped surfaces 27 are spliced on a side away from the optical fiber unit 30 to form the second installation cavity 22.

In this embodiment, two adjacent third arcwall faces 27 are spliced on the side away from the optical fiber unit 30 to form the second installation cavity 22, the power unit 10 is installed in the second installation cavity, thus, the power unit 10 is arranged at the periphery of the optical fiber unit 30 at intervals, the internal structure of the submarine cable is arranged more uniformly, and the optical fiber unit 30 is located in the center of the area surrounded by the three power units 10, thus, the situation that the power unit 10 extrudes the optical fiber unit 30 to the edge of the submarine cable in the construction circulation process can be avoided, the stability of the internal structure of the submarine cable can be improved, the optical fiber unit 30 cannot deform excessively, and fiber breakage is avoided.

Referring to fig. 1 to 5 in combination, in one embodiment of the present invention, a projection of the first arc-shaped surface 24 on the cross section of the submarine cable is a first arc, a projection of the second arc-shaped surface 26 on the cross section of the submarine cable is a second arc, and an arc length L1 of the first arc satisfies:

the arc length L2 of the second arc satisfies:

where H is the distance between the second arc-shaped face 26 and the central axis of the submarine cable and d is the diameter of the optical fiber unit 30.

In this embodiment, the submarine cable further comprises a shielding layer, the shielding layer 60 is coated on the periphery of the filling unit, and the arc length of the first arc line satisfies that

The contact area between the first arc-shaped face 24 and the shielding layer 60 can be ensured, and the arc length of the second arc line satisfies:

therefore, after the step surfaces are connected in pairs, the first arc-shaped surfaces 24 of the three filling subunits 23 can be spliced to form the first installation cavity 21, so that the first installation cavity 21 is prevented from being completely attached to the outer wall surface of the optical fiber unit 30, and the stability of the internal structure of the submarine cable is ensured.

Referring to fig. 1 to 5 in combination, in one embodiment of the present invention, the step surface includes a first step 40 and a second step 50, the first step 40 is located on a side of the step surface close to the optical fiber unit 30, the second step 50 is located on a side of the step surface far from the optical fiber unit 30, and a relationship of a height h1 of the first step 40, a height h2 of the second step 50, and a minimum distance h between an outer wall surface of the power unit 10 and the optical fiber unit 30 satisfies: h is h1+ h 2.

In the present embodiment, the relationship of the height h1 of the first step 40, the height h2 of the second step 50, and the minimum distance h between the outer wall surface of the power unit 10 and the optical fiber unit 30 satisfies: h1+ h2, so that two adjacent step surfaces can be ensured to be smoothly spliced, and the first installation cavity 21 formed after splicing can just accommodate the optical fiber unit 30. Specifically, the widths of the first step 40 and the second step 50 are both m, and the value range of m is 5-10 mm.

Referring collectively to fig. 1-5, in one embodiment of the invention, the maximum distance K1 between two first steps 40 on the same splice satisfies:

the minimum distance K2 between the two second steps 50 satisfies:

where d is the diameter of the optical fiber unit 30.

Referring to fig. 1 to 5, in one embodiment of the present invention, the side of the power unit 10 close to the optical fiber unit 30 is attached to the third arc-shaped surface 27.

In this embodiment, one side of the power unit 10 close to the optical fiber unit 30 is attached to the third arc-shaped surface 27, so that the power unit 10 can extrude the splicing part, the first installation cavity 21 is tightly attached to the optical fiber unit 30, the optical fiber unit 30 is limited, and the optical fiber unit 30 is prevented from bending and deforming along the radial direction in the construction and circulation process, so that the optical fiber unit 30 is prevented from breaking due to overlarge stress.

Referring to fig. 1 to 5 in combination, in one embodiment of the present invention, the relationship between the distance H between the second arc-shaped surface 26 and the central axis of the submarine cable, the diameter D of the optical fiber unit, and the diameter D of the power unit satisfies:

in the cross-section of the submarine cable,the projection of the third arc-shaped surface 27 is a third arc line, the projection of the power unit 10 is a circle, the third arc line and the circle are gradually separated from each other from the joint end point P along the direction far away from the optical fiber unit 30, the connecting line between the joint end point P and the center of the power unit 10 is L3, the connecting line between the center point of the optical fiber unit 30 and the center of the power unit 10 is L4, the included angle between L3 and L4 is α, and the value range of α is 60 degrees or more and 90 degrees or less.

In the present embodiment, α is greater than or equal to 60 ° and less than or equal to 90 °, a contact area between the power unit 10 and the filling unit 20, that is, a contact area between the power unit 10 and the third arc-shaped surface 27 can be ensured, so that the power unit 10 can press the filling unit 20 at the contact position, thereby limiting the optical fiber unit 30.

Referring to fig. 1 to 5 in combination, in one embodiment of the present invention, the submarine cable further includes a shielding layer 60, the power unit 10 and the filling subunit 23 are disposed inside the shielding layer 60, the second arc-shaped surface 26 is attached to the shielding layer 60, and the side of the power unit 10 away from the optical fiber unit 30 is tangent to the shielding layer 60 at a point Q.

In this embodiment, the second arc-shaped surface 26 is attached to the shielding layer 60, and the first arc-shaped surface 24 is attached to the optical fiber unit 30, so that the filler subunit 23 can support the shielding layer 60, one side of the power unit 10 close to the optical fiber unit 30 is attached to the third arc-shaped surface 27, and one side of the power unit 10 far from the optical fiber unit 30 is tangent to the shielding layer 60, so that the roundness of the submarine cable can be ensured, and the submarine cable is prevented from being locally deformed in the construction and circulation process.

Referring to fig. 1 to 5 in combination, in one embodiment of the present invention, in a cross-section of the submarine cable, a line between one end of the second arc and the center of the optical fiber unit 30 is L5, a line between the point Q and the center of the optical fiber unit 30 is L6, an angle between L5 and L6 is θ, and θ is in a range of 0 ° to 30 °.

In this embodiment, the value range of θ is 0 ° or more and 30 ° or less, θ has different values, the areas of the power unit 10 covered by the filling units 20 are different, and a proper θ can be selected according to the use scene, so as to improve the applicability of the submarine cable, and when θ is 0 °, the power unit 10 is completely covered by the filling units, and has the strongest compressive resistance, and is suitable for being used in an ultra-high water pressure environment with a water depth of over 1000 meters.

From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects: by arranging the filling unit which comprises the first mounting cavity and the second mounting cavity, the first mounting cavity is positioned in the region range enclosed by the three power units, the optical fiber unit is arranged in the first mounting cavity, so that the optical fiber unit is positioned in the region range enclosed by the three power units, namely, the optical fiber unit is positioned at the center of the submarine cable, the force borne by the central area of the submarine cable is small and the deformation quantity is small in the process of production and construction circulation, the three power units are arranged at intervals along the circumferential direction of the first mounting cavity and can extrude the filling units in different directions, so that the inner wall of the first mounting cavity can be tightly attached to the outer wall surface of the optical fiber unit, the optical fiber unit is extruded and limited, the deformation of the optical fiber unit in the radial direction is reduced, the structural stability of the optical fiber unit is guaranteed, and the fiber breakage in the production and construction circulation processes is avoided.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the accompanying drawings are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are capable of operation in sequences other than those illustrated or described herein.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A submarine cable, comprising:

at least three power units (10);

the filling unit (20) comprises a first mounting cavity (21) and a plurality of second mounting cavities (22), the central area of the filling unit (20) is within the area range surrounded by at least three power units (10), the first mounting cavity (21) is located in the central area of the filling unit (20), the plurality of second mounting cavities (22) are arranged at intervals along the circumferential direction of the first mounting cavity (21), and one power unit (10) is mounted in each second mounting cavity (22); and

the optical fiber unit (30) is installed in the first installation cavity (21), and the inner wall surface of the first installation cavity (21) is attached to the outer wall surface of the optical fiber unit (30).

2. The submarine cable according to claim 1, wherein the filler unit (20) comprises at least three filler subunits (23), the at least three power units (10) and the at least three filler subunits (23) are arranged alternately in the circumferential direction, each filler subunit (23) comprises a spliced portion, the spliced portions are located at one ends of the filler subunits (23) close to the optical fiber units (30), the spliced portions are connected in pairs, the spliced portions form a first installation cavity (21) for accommodating the optical fiber units (30) at the inner circumferential side, and the inner wall surface of the first installation cavity (21) is attached to the outer wall surface of the optical fiber units (30); and/or the presence of a gas in the gas,

the central area of the filling unit (20) is in the center of an area enclosed by at least three power units (10), and the first mounting cavity (21) is located in the center of the central area.

3. The submarine cable according to claim 2, wherein the splicing portions comprise first arc-shaped surfaces (24) and splicing surfaces (25) located at two ends of the first arc-shaped surfaces (24), the splicing surfaces (25) are step surfaces, three splicing portions are connected in pairs through the step surfaces to form a step limiting structure, and the three first arc-shaped surfaces (24) are spliced to form the first mounting cavity (21).

4. Submarine cable according to claim 3, wherein the filler subunit (23) further comprises a second curved face (26) and two third curved faces (27), the second curved face (26) being located on the side of the splice remote from the first curved face (24), two third curved faces (27) being located between the first curved face (24) and the second curved face (26), two adjacent third curved faces (27) being spliced on the side remote from the fibre unit (30) to form the second mounting cavity (22).

5. Submarine cable according to claim 4, wherein the projection of the first curved surface (24) on the submarine cable cross-section is a first arc and the projection of the second curved surface (26) on the submarine cable cross-section is a second arc, the first arc having an arc length L1 such that:

the arc length L2 of the second arc satisfies:

wherein H is the distance between the second arc-shaped face (26) and the submarine cable central axis, and d is the diameter of the optical fiber unit (30).

6. Submarine cable according to claim 5, wherein the step-plane comprises a first step (40) and a second step (50), the first step (40) being located on the side of the step-plane close to the fibre unit (30) and the second step (50) being located on the side of the step-plane remote from the fibre unit (30), the relationship between the height h1 of the first step (40), the height h2 of the second step (50), the minimum distance h between the outer wall of the power unit (10) and the fibre unit (30) being such that: h is h1+ h 2.

7. Submarine cable according to claim 5, wherein the relationship between the distance H between the second arc-shaped face (26) and the submarine cable central axis, the diameter D of the optical fibre unit (30), the diameter D of the power unit (10) is such that:

8. submarine cable according to claim 6, wherein the maximum distance K1 between two first steps (40) on the same splice satisfies:

the minimum distance K2 between two of the second steps (50) satisfies:

wherein d is the diameter of the optical fiber unit (30).

9. Submarine cable according to claim 4, wherein the side of the power unit (10) close to the fibre unit (30) is flush with the third curved face (28).

10. Submarine cable according to claim 9, wherein, in a cross-section of the submarine cable, the projection of the third arc-shaped surface (27) is a third arc, the projection of the power unit (10) is a circle, the third arc is gradually separated from the circle in a direction away from the fiber unit (30) from the abutting end point P, the line between the abutting end point P and the center of the power unit (10) is L3, the line between the center of the fiber unit (30) and the center of the power unit (10) is L4, the angle between L3 and L4 is α, α has a value in the range of 60 ° to 90 °.

11. Submarine cable according to claim 5, further comprising a shielding layer (60), wherein the power unit (10) and the filler subunit (23) are arranged inside the shielding layer (60), wherein the second arcuate surface (26) is in abutment with the shielding layer (60), and wherein the side of the power unit (10) remote from the fibre unit (30) is tangent to the shielding layer (60) at point Q.

12. Submarine cable according to claim 11, wherein, in its cross-section, the line connecting one end of the second arc to the center of the fibre unit (30) is L5, the line connecting point Q to the center of the fibre unit (30) is L6, the angle between L5 and L6 is θ, θ being in the range 0 ° to 30 °.