Large-length alternating-current optical fiber composite submarine cable

Abstract

The utility model discloses a large-length AC optical fiber composite submarine cable, which is of a composite structure and comprises power wire cores, an optical transmission unit, a pressure-bearing protection filling and an outer layer protection structure, one side, close to the outer layer protection structure, of the pressure-bearing protection filling is provided with a wire groove, and the power wire cores are arranged at the center of the cable in an annular array mode. Pressure-bearing protection fillers are filled in gaps between the adjacent power wire cores and the outer side of the outer-layer protection structure, the optical transmission units are arranged in wire grooves of the pressure-bearing protection fillers, each power wire core is composed of a plurality of power wire core sections and a factory flexible joint, and the factory flexible joint is arranged between every two adjacent power wire core sections. According to the utility model, the factory flexible joint is adopted to connect the two different power wire core sections, and the power wire core part can be infinitely extended theoretically, so that compared with the prior art, the optical fiber integrity is better, and compared with the conventional segmented laying scheme, the waterproof performance is better, and the working safety is better.

Description

Technical Field

[0001] The utility model relates to a long-length AC optical fiber composite submarine cable, belonging to the technical field of cables. Background Art

[0002] With the continuous development of offshore wind power technology, wind farms are gradually developing from offshore to deep sea areas. Due to the requirements of transmission distance, submarine cable technology is gradually developing towards high voltage and long length. Under the same transmission power, the higher the voltage, the smaller the current. The use of high voltage transmission can effectively reduce the heat loss caused by the current and the cost of long-distance transmission. The current mainstream transmission cables are gradually transitioning from 220kV AC cables to 330kV or higher-level 500kV cross-linked polyethylene insulated long-length three-core AC submarine cables. Due to process limitations in the cable manufacturing process, there is generally a length limit for a single section during the production process. During use, multiple sections of cables need to be connected and used. The stability of the connection process greatly affects the performance of the cable. Therefore, the development of a more stable connection method has become a top priority. Utility Model Content

[0003] The utility model aims to provide a long-length AC optical fiber composite submarine cable.

[0004] The technical solution for achieving the purpose of the utility model is: a long-length AC optical fiber composite submarine cable, which is a composite structure, including a power core, an optical transmission unit, a pressure-bearing protective filling and an outer protective structure. The pressure-bearing protective filling is provided with a wire groove close to the outer protective structure. The power core annular array is arranged at the center of the cable, and the gaps between adjacent power cores and the outer side of the outer protective structure are filled with pressure-bearing protective filling. The optical transmission unit is arranged in the wire groove of the pressure-bearing protective filling. The power core is composed of a plurality of power core segments and a factory flexible joint, and the factory flexible joint is arranged between two adjacent power core segments.

[0005] The utility model uses a factory soft joint to connect two different power core segments, and then places the power core, optical transmission unit and pressure-bearing protective filling into the outer protective structure for on-site processing. The power core part can be infinitely extended in theory, and the optical fiber integrity is better than the solution of using factory soft joints to connect submarine optical fiber composite cables in the prior art. During the laying process, it can be ensured that there is no interface in the outer protective structure as a whole. Compared with the conventional segmented laying solution, the long-length AC optical fiber composite cable of this solution has better mechanical strength, better waterproof performance and better working safety.

[0006] Further or optionally, the structure of the factory flexible joint is refined, the power line core section includes a water-blocking conductor, a water-blocking tape, a conductor shielding layer, an insulating layer, an insulating shielding layer, a waterproof layer, an anti-corrosion layer and an inner sheath arranged from the inside to the outside, the factory flexible joint includes a conductor recovery layer, a conductor water-blocking layer and a conductor shielding layer recovery layer, an insulating recovery layer, an insulating shielding recovery layer, a water-blocking layer recovery layer and an anti-corrosion layer recovery layer and an inner sheath recovery layer arranged from the inside to the outside, and the corresponding functional layers are in a one-to-one correspondence. When in use, the water-blocking conductor is connected to the conductor recovery layer, the water-blocking tape and the conductor shielding layer are connected to the conductor water-blocking layer and the conductor shielding layer recovery layer, the insulating layer is connected to the insulating recovery layer, the insulating shielding layer is connected to the insulating shielding layer recovery layer, the waterproof layer and the anti-corrosion layer are connected to the water-blocking layer recovery layer and the anti-corrosion layer recovery layer, and the inner sheath is connected to the inner sheath recovery layer. This connection method ensures that the functions between the layers are normally performed, the overall insulation and water-blocking functions of the power line core are always relatively complete, and the loss of various functional parameters of the power line core is small after the connection is completed.

[0007] Further or optionally, an integrated structure is provided, wherein the radial cross-section is an axisymmetric fan-shaped structure, including two inner concave arcs located at the radius of the fan-shaped structure and an outer arc located at the edge of the fan-shaped arc, wherein the midpoint of the outer arc is provided with a notch located on the symmetry axis of the axisymmetric structure, wherein the inner concave arc is fitted with the power line core, the outer arc is fitted with the outer protective structure, and the optical transmission unit is arranged in the notch; during use, both the power line core and the optical transmission unit can be effectively fixed, and the performance of the optical fiber composite submarine cable is more stable when the optical fiber composite submarine cable is impacted by water flow.

[0008] Further or optionally, the surface of the conductor shielding layer of the optical transmission unit is coated with fiber paste and is sleeved with a stainless steel loose tube.

[0009] In addition, the power line core adopts a water-blocking conductor wrapped with a semi-conductive water-resistant tape, its waterproof layer is a metal lead sheath or an integrated sheath, its anti-corrosion layer is asphalt, and the inner sheath is polyethylene.

[0010] This structure can ensure that the optical fiber composite submarine cable has multiple effective mechanical protections and is better adaptable in situations where deep sea water pressure is high and the requirements for tensile strength are high.

[0011] Further or optionally, the conductor recovery part of the factory flexible joint has a tensile strength of not less than 180 MPa, which can ensure that the power line core part has sufficient mechanical strength to avoid breakage when the optical fiber composite submarine cable is impacted.

[0012] Further or optionally, the micropores, opaque impurities and protrusions between two adjacent layers of the conductor shielding layer, insulation layer and insulation shielding layer of the power core conductor should be no larger than 0.018mm to ensure that the gap is small enough and the water-blocking performance meets the requirements. During the production process, the conductor shielding layer, insulation layer and insulation shielding layer adopt a three-layer co-extrusion process, at which time the delamination phenomenon between the three layers will be effectively reduced, and the waterproof performance of the cable will be better.

[0013] Further or optionally, the partial discharge test sensitivity of the factory flexible joint is greater than 435kV, and the holding time under the 580kV discharge test is greater than 60min. At this time, the cable can ensure the long-term power transmission capacity and construction strength of 500kV voltage in deep water areas. At this time, the optical fiber composite submarine cable can maintain normal operation under high voltage, and the working conditions are more stable.

[0014] Further or optionally, the outer protective structure includes a cable tying tape, an isolation lining layer, a tensile protective layer, and an anti-corrosion marking outer layer arranged from the inside to the outside, wherein the tensile protective layer adopts high-strength galvanized anti-corrosion steel wire, and the anti-corrosion marking outer layer is a polypropylene rope, the surface of the polypropylene rope is coated with asphalt and provided with a yellow marking line. The outer protective structure has high overall mechanical strength, good corrosion resistance and water blocking capabilities, and has a certain anti-bite function, and has good adaptability in extreme environments.

[0015] Further or optionally, the polypropylene rope of the anti-corrosion marking outer layer is two layers, and the diameter of the polypropylene rope monofilament is 3.0 mm to ensure the strength of the outer layer.

[0016] Further or optionally, the water-blocking conductor is formed by twisting T-shaped conductor monofilaments, and its outer layer is wrapped with a semiconductor water-blocking tie. Compared with the circular conductor single-wire structure, the overall conductor filling rate of the power line core is better when the T-shaped conductor monofilament structure is adopted, and the current carrying capacity of the power line core is larger.

[0017] By adopting the above technical solution, the utility model has the following beneficial effects:

[0018] (1) The utility model adopts a factory flexible joint to connect two different power line core sections, and then places the power line core, the optical transmission unit and the pressure-bearing protective filling into the outer protective structure for on-site processing. The power line core part can theoretically be infinitely extended. Compared with the scheme of using factory flexible joints to connect submarine optical fiber composite cables in the prior art, the optical fiber integrity is better; during the laying process, it can be ensured that there is no interface on the outer protective structure as a whole. Compared with the conventional segmented laying scheme, the long-length AC optical fiber composite cable of this scheme has better mechanical strength, better waterproof performance and better working safety.

[0019] (2) The factory flexible joint structure of the utility model corresponds to each part of the power line core segment. This connection method can ensure the normal function of each layer, and the overall insulation and water-blocking functions of the power line core are always relatively complete. After the connection is completed, the loss of various functional parameters of the power line core is relatively small.

[0020] (3) The radial cross-section of the pressure-bearing protective filling of the utility model is approximately a fan-shaped structure. During use, the power line core and the optical transmission unit can be effectively fixed, and the performance of the optical fiber composite submarine cable is more stable when it is impacted by water flow.

[0021] (4) The optical fiber unit of the utility model is provided with a separate waterproof and mechanical reinforcement structure, which can ensure that the optical fiber composite submarine cable has multiple effective mechanical protections and is more adaptable in situations where the deep sea water pressure is high and the tensile strength requirements are high.

[0022] (5) The utility model strictly controls the tensile strength of the conductor recovery part of the factory flexible joint, which can ensure that the power line core part has sufficient mechanical strength to avoid breakage when the optical fiber composite submarine cable is impacted.

[0023] (6) The conductor shielding layer, insulating layer and insulating shielding layer of the utility model adopt a three-layer co-extrusion process and strictly control the molding effect, and have better waterproof performance than cables.

[0024] (7) The utility model selects the electrical performance of the factory flexible joint to ensure normal operation in the high-pressure and high-disturbance environment on the seabed, and its performance is more stable than that of general factory flexible joints.

[0025] (8) The utility model is designed with an outer protective structure that has better corrosion resistance and water barrier properties, and has a certain anti-bite function, and has better adaptability in extreme environments.

[0026] (9) The utility model optimizes the number of polypropylene rope layers and diameter of the anti-corrosion marking outer layer, and the outer layer has higher strength.

[0027] (10) The water-blocking conductor of the utility model adopts a T-shaped structure in which the conductor single wires are twisted and the outer layer is wrapped with a semi-conductive water-blocking tie. Compared with the general round conductor single-wire structure, the conductor filling rate of the power line core is higher and the current carrying capacity of the power line core is larger. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to make the content of the utility model easier to understand, the utility model is further described in detail according to specific embodiments and in conjunction with the accompanying drawings.

[0029] Figure 1 This is a schematic diagram of the overall structure of the cable of the utility model.

[0030] Figure 2This is a schematic diagram of the factory flexible joint structure of the utility model.

[0031] The reference numerals in the accompanying drawings are:

[0032] Power line core 1, power line core section 11, water-blocking conductor 111, water-blocking tape 112, conductor shielding layer 113, insulation layer 114, insulation shielding layer 115, waterproof layer 116, anti-corrosion layer 117, inner sheath 118, factory flexible joint 12, conductor recovery layer 121, conductor water-blocking layer and conductor shielding layer recovery layer 122, insulation recovery layer 123, insulation shielding recovery layer 124, water-blocking layer recovery layer and anti-corrosion layer recovery layer 125, inner sheath recovery layer 126;

[0033] Optical transmission unit 2;

[0034] Pressure-bearing protective filling 3, inner concave arc 31, outer arc 32, notch 33;

[0035] Outer protective structure 4, cabling and tightening tape 41, isolation lining layer 42, tensile protective layer 43, anti-corrosion marking outer layer 44. DETAILED DESCRIPTION

[0036] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0037] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be clearly and completely described below in conjunction with the drawings in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Generally, the components of the embodiments of the utility model described and shown in the drawings here can be arranged and designed in various different configurations.

[0038] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the present invention to be protected, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0040] In the description of the embodiments of the present utility model, it should be understood that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the utility model product is conventionally placed when in use, or are the orientations or positional relationships conventionally understood by those skilled in the art. They are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present utility model.

[0041] In the description of the embodiments of the present utility model, it is also necessary to explain that, unless otherwise clearly stipulated and limited, the terms "set", "installed", "connected", and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, or it can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances. The utility model is further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the utility model, and cannot be used to limit the scope of protection of the utility model.

[0042] (Example 1)

[0043] See Figure 1 and Figure 2 , a long-length AC optical fiber composite submarine cable of this embodiment is a composite structure, including a power core 1, an optical transmission unit 2, a pressure-bearing protective filling 3 and an outer protective structure 4, the pressure-bearing protective filling 3 is provided with a wire groove near the outer protective structure 4, the power core 1 is arranged in a ring array at the center of the cable, the outer gaps between adjacent power cores 1 and the outer protective structure 4 are filled with pressure-bearing protective filling 3, the optical transmission unit 2 is arranged in the wire groove of the pressure-bearing protective filling 3, the power core 1 is composed of a plurality of power core segments 11 and a factory flexible joint 12, and the factory flexible joint 12 is arranged between two adjacent power core segments 11.

[0044] When in use, two sections of power line core segments 11 are connected using factory flexible joints 12, and then the optical transmission unit 2 is placed in the pressure-bearing protective filling 3, and then the outer protective structure 4 is covered before laying. By controlling the construction progress in this process, it can be ensured that the outer protective structure 4 of the long-length AC optical fiber composite submarine cable is always intact, and there will be no situation where the optical fiber is interrupted multiple times and needs to be reconnected. The overall mechanical strength and waterproof performance of the long-length AC optical fiber composite submarine cable laid by this solution will be much greater than that of the conventional spliced ​​composite optical cable, and its overall stability during work will be greatly improved, and the probability of maintenance will be greatly reduced.

[0045] The power line core segment 11 includes a water-blocking conductor 111, a water-blocking tape 112, a conductor shielding layer 113, an insulating layer 114, an insulating shielding layer 115, a waterproof layer 116, an anti-corrosion layer 117 and an inner sheath 118 arranged from the inside to the outside, and the factory flexible joint 12 includes a conductor recovery layer 121, a conductor water-blocking layer and a conductor shielding layer recovery layer 122, an insulating recovery layer 123, an insulating shielding layer recovery layer 124, a water-blocking layer recovery layer and an anti-corrosion layer recovery layer 125 and an inner sheath recovery layer 126 arranged from the inside to the outside, and the corresponding functional layers are in a one-to-one correspondence. When in use, the water-blocking conductor 111 is connected to the conductor recovery layer 121, the water-blocking tape 112 and the conductor shielding layer 113 are connected to the conductor water-blocking layer and the conductor shielding layer recovery layer 122, the insulating layer 114 is connected to the insulation recovery layer 123, the insulating shielding layer 115 is connected to the insulating shielding layer recovery layer 124, the waterproof layer 116 and the anti-corrosion layer 117 are connected to the water-blocking layer recovery layer and the anti-corrosion layer recovery layer 122, and the inner sheath 118 is connected to the inner sheath recovery layer 126.

[0046] During the operation, the welding between the conductor recovery 121 of the factory flexible joint 12 and the water-blocking conductor 111 adopts argon arc welding with a center layer and adjacent layer flat head spacing of 2mm, and the other layers are welded by staggered argon arc welding and layered grinding. The tensile strength of the conductor recovery layer is not less than 180MPa.

[0047] The conductor recovery layer 121 of the factory flexible joint 12 has a tensile strength of not less than 180 MPa.

[0048] The local discharge test sensitivity of the factory flexible joint 12 is greater than 435kV, and the holding time under the 580kV discharge test is greater than 60min. At this time, the long-term power transmission capacity and construction strength of 500kV voltage can be guaranteed in deep water areas.

[0049] In order to improve the stability of the internal components of the composite optical cable, the pressure-bearing protective filling 3 is set as an integrated structure, and its radial cross-section is an axisymmetric fan-shaped structure, including two inner concave arcs (31) located at the fan-shaped radius position and an outer arc (32) located at the fan-shaped arc edge position, and the midpoint of the outer arc (32) is provided with a notch (33) located on the symmetry axis of the axisymmetric structure, the inner concave arc (31) is in contact with the power line core (1), the outer arc (32) is in contact with the outer protective structure (4), and the optical transmission unit (2) is arranged in the notch (33). After the optical transmission unit is fixed, the outer protective structure 4 is laid on its outer layer.

[0050] The outer protective structure 4 includes a cable tying tape 41, an isolation lining layer 42, a tensile protective layer 43, and an anti-corrosion marking outer layer 44 arranged from the inside to the outside, wherein the tensile protective layer 43 adopts high-strength galvanized anti-corrosion steel wire, and the anti-corrosion marking outer layer 44 is a polypropylene rope, the surface of the polypropylene rope is coated with asphalt and is provided with a yellow marking line; in order to ensure the strength of the outer protective structure, the polypropylene rope of the anti-corrosion marking outer layer 44 is set to two layers, and the monofilament diameter of the polypropylene rope is 3.0 mm.

[0051] During the laying process, attention should be paid to the mechanical strength of the tensile protective layer 43. The key issue is to design the number and wire diameter of the high-strength galvanized anti-corrosion layer steel wire, which is calculated based on the allowable loading tension during laying and dragging and the tension on the submarine cable at the design water depth.

[0052] The specific calculation process is as follows: Assuming that the allowable loading tension Tmax of the submarine cable during laying and dragging is greater than the tension T1 of the submarine cable at the designed water depth, the number and diameter of the steel wires of the designed tensile protective layer (12) meet the requirements;

[0053] The number of steel wires and the wire diameter

[0054] INT—Round without carry

[0055] Where: D——target value of cable diameter before armoring, mm

[0056] d——diameter of round wire, mm

[0057] k——wire twist coefficient, steel wire is 1.08

[0058] The calculation formula for the tension T1 of the submarine cable at the design water depth is:

[0059] T1=1.3W S d+H

[0060] Where: W S ——Gravity of 1m submarine cable in water (N / m)

[0061] d——maximum water depth in meters;

[0062] H is the maximum allowable tension of the underwater contact point on the cable, in N, calculated as:

[0063] H=W S d

[0064] Weight of submarine cable in seawater:

[0065] W S =W-(πD 2 / 4)×r

[0066] Where: WS ——Gravity of 1m submarine cable in water (N / m)

[0067] W——The gravity of 1m submarine cable in the air (N / m)

[0068] D——Outer diameter of submarine cable (m)

[0069] r——seawater density (1.025kg / m 3 )

[0070] The calculation formula for the allowable loading tension Tmax during the laying and dragging of submarine cables is:

[0071] T max =NSση / Nc

[0072] Where: N——number of steel wires;

[0073] S——cross-sectional area of ​​a single steel wire, wire diameter in mm;

[0074] σ——tensile strength of steel wire, 340N / mm 2 ;

[0075] η——Strength loss coefficient after steel wire twisting, taken as 0.9;

[0076] Nc——safety factor, take 3.0;.

[0077] In order to ensure the waterproof capability and mechanical structure of the power line core 1 itself, the power line core 1 is limited to a water-blocking conductor wrapped with a semi-conductive water-resistant tape, the waterproof layer 116 is a metal lead sheath or an integrated sheath, the anti-corrosion layer 117 is asphalt, and the inner sheath 118 is polyethylene; the surface of the optical transmission unit 2 is coated with fiber paste and is sheathed with a stainless steel loose tube;

[0078] In order to enhance the current carrying capacity of the power line core 1, the water-blocking conductor 111 is formed by twisting T-shaped structure conductor monofilaments, and a semi-conductive water-blocking tie is wrapped around its outer layer.

[0079] In order to further ensure the waterproof performance of the power core 1, the conductor shielding layer 113, the insulating layer 114 and the insulating shielding layer 115 of the power core 1 conductor are limited to a three-layer co-extrusion process, wherein the micropores, opaque impurities and protrusions between two adjacent layers should be less than 0.018mm.

[0080] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A long-length AC optical fiber composite submarine cable, characterized in that: The invention is a composite structure, comprising a power line core (1), an optical transmission unit (2), a pressure-bearing protective filling (3) and an outer protective structure (4); the pressure-bearing protective filling (3) is provided with a wire groove near the outer protective structure (4); the power line core (1) is arranged in a ring array at the center of the cable; the outer gaps between adjacent power line cores (1) and the outer protective structure (4) are filled with the pressure-bearing protective filling (3); the optical transmission unit (2) is arranged in the wire groove of the pressure-bearing protective filling (3); the power line core (1) is composed of a plurality of power line core segments (11) and factory flexible joints (12); the factory flexible joints (12) are arranged between two adjacent power line core segments (11).

2. The long-length AC optical fiber composite submarine cable according to claim 1, characterized in that: The power line core segment (11) comprises a water-blocking conductor (111), a water-blocking tape (112), a conductor shielding layer (113), an insulating layer (114), an insulating shielding layer (115), a waterproof layer (116), an anti-corrosion layer (117) and an inner sheath (118) arranged from the inside to the outside, and the factory flexible joint (12) comprises a conductor recovery layer (121), a conductor water-blocking layer and a conductor shielding layer recovery layer (122), an insulating recovery layer (123), an insulating shielding recovery layer (124), a water-blocking layer recovery layer and an anti-corrosion layer recovery layer (125) and an inner sheath recovery layer arranged from the inside to the outside. The corresponding functional layers are in a one-to-one correspondence, specifically, the water-blocking conductor (111) corresponds to the conductor recovery layer (121); the water-blocking tape (112) and the conductor shielding layer (113) correspond to the conductor water-blocking layer and the conductor shielding layer recovery layer (122); the insulating layer (114) corresponds to the insulating recovery layer (123); the insulating shielding layer (115) corresponds to the insulating shielding recovery layer (124); the waterproof layer (116) and the anti-corrosion layer (117) correspond to the water-blocking layer recovery layer and the anti-corrosion layer recovery layer (125); and the inner sheath (118) corresponds to the inner sheath recovery layer (126).

3. A long-length AC optical fiber composite submarine cable according to claim 1 or 2, characterized in that: The pressure-bearing protective filling (3) is an integrated structure, and its radial cross-section is an axisymmetric fan-shaped structure, comprising two inner concave arcs (31) located at the fan-shaped radius position and an outer arc (32) located at the fan-shaped arc edge position, and a notch (33) located on the symmetry axis of the axisymmetric structure is provided at the midpoint of the outer arc (32), the inner concave arc (31) is fitted with the power line core (1), the outer arc (32) is fitted with the outer protective structure (4), and the optical transmission unit (2) is arranged in the notch (33).

4. The long-length AC optical fiber composite submarine cable according to claim 2, characterized in that: The surface of the optical transmission unit (2) is coated with fiber paste and is sleeved with a stainless steel loose tube.

5. The long-length AC optical fiber composite submarine cable according to claim 2, characterized in that: The conductor recovery layer (121) of the factory flexible joint (12) has a tensile strength of not less than 180 MPa.

6. The long-length AC optical fiber composite submarine cable according to claim 2, characterized in that: The micropores, opaque impurities and protrusions between two adjacent layers of the conductor shielding layer (113), the insulation layer (114) and the insulation shielding layer (115) of the power line core (1) conductor are no larger than 0.018 mm.

7. The long-length AC optical fiber composite submarine cable according to claim 2, characterized in that: The local discharge test sensitivity of the factory flexible joint (12) is greater than 435 kV, and the holding time under a 580 kV discharge test is greater than 60 minutes.

8. The long-length AC optical fiber composite submarine cable according to claim 2, characterized in that: The outer protective structure (4) includes a cable tie wrap (41), an isolation lining layer (42), a tensile protective layer (43), and an anti-corrosion marking outer layer (44) arranged from the inside to the outside, wherein the tensile protective layer (43) is made of high-strength galvanized anti-corrosion steel wire, and the anti-corrosion marking outer layer (44) is a polypropylene rope, the surface of the polypropylene rope is coated with asphalt and is provided with a yellow marking line.

9. The long-length AC optical fiber composite submarine cable according to claim 8, characterized in that: The polypropylene rope of the anti-corrosion identification outer coating layer (44) is two layers, and the diameter of the polypropylene rope single wire is 3.0 mm.

10. The long-length AC optical fiber composite submarine cable according to claim 2, characterized in that: The water-blocking conductor (111) is formed by twisting T-shaped structure conductor monofilaments, and its outer layer is wrapped with a semi-conductive water-blocking tie.

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