Large current flexible water-tight power cable and method of manufacturing the same

Abstract

The present application provides a kind of big current-carrying soft part water-tight power cable, comprising: by conductor single wire and hydrophilic expansion yarn twist into strand strand; By the strand and the stock of hydrophilic expansion yarn is complexly twisted to form water-tight conductor, the outermost gap of outermost strand is filled with silicon-based elastomer water-blocking glue and is wrapped with water-blocking polyester tape; Extrusion-coated conductor insulation layer; Extrusion-coated water-blocking inner lining; Braided aramid fiber tensile braided layer, and the gap in braided layer is filled with water-blocking glue, to form longitudinal waterproof barrier, then wrapped with water-blocking polyester tape; Extrusion-coated waterproof outer sheath on the outermost layer.The present application proposes that the cable is based on withstands predetermined pressure, structural size parameter and the water absorption length of water absorption of hydrophilic water-swelling water-blocking material, meets the water penetration-cable structure design under different environments and conditions, can simultaneously realize large current-carrying capacity (the current-carrying capacity in 10 DEG C seawater is not less than 1000A), super soft (minimum bending radius is 3 times cable diameter), meets the characteristics of water-tight application under 650m water depth.

Description

Technical Field

[0001] This invention relates to the field of watertight cable technology, and more specifically to a watertight power cable with a high current-carrying flexible section and a method for manufacturing the same. Background Technology

[0002] The trend towards deep-sea exploration and the development of underwater vessels in greater depths places demands on supporting underwater exploration equipment requiring greater depth and power. After deep-water operations, this equipment needs to be rapidly recharged from the mother ship via a watertight power cable. When not in use, the watertight power cable is wound onto a small cable reel located on the mother ship. When needed, it is towed from the reel to the exploration equipment, and then retracted after use.

[0003] Based on the high-power fast charging requirements and winding requirements in deep-water environments, watertight charging cables must possess characteristics such as high current carrying capacity (current carrying capacity in seawater at 10℃ not less than 1000A), ultra-flexibility (minimum bending radius of 3 times the cable diameter), and watertightness at a depth of 650m. However, existing watertight cables have significant defects that prevent them from meeting the fast charging needs of high-power deep-water exploration equipment. Specifically, these defects include: (1) the minimum bending radius of existing longitudinal watertight cables can only be no less than 6 times the cable outer diameter, resulting in a large bending radius that cannot be wound on small-sized reels placed in the confined space of the mother ship; (2) existing watertight cables have low operating temperatures and low rated current carrying capacity. To achieve a current carrying capacity of 1000A, the conductor cross-section would need to reach 800mm². 2 This results in a large outer diameter, heavy weight, high hardness, and difficulty in bending of the cable; (3) the watertight cable with existing hydrophilic water-swellable polymer water-blocking filling cannot be preset for the water seepage length under a given water pressure, and the impact of the length on use cannot be determined. Summary of the Invention

[0004] In view of the defects and deficiencies of the existing technology, the purpose of this invention is to provide a longitudinal watertight cable design method based on the calculation of the seepage length by the expansion rate of the water-blocking filler of a hydrophilic water-swellable polymer, and based on this, propose a watertight power cable with a large current-carrying flexible section to meet the performance requirements of deep-sea underwater exploration equipment with large current-carrying capacity (current-carrying capacity of not less than 1000A in seawater at a temperature not higher than 10℃), ultra-flexible (minimum bending radius of 3 times the cable diameter), and watertight (6.75MPa) at a water depth of 650m.

[0005] According to a first aspect of the present invention, a watertight power cable with a high current-carrying flexible portion is provided, comprising:

[0006] The strand is made of multiple conductor single wires twisted together with hydrophilic expandable yarn and wrapped with water-blocking polyester tape, wherein the conductor single wires and hydrophilic expandable yarn are arranged in a cross pattern.

[0007] The watertight conductor is made of strands and hydrophilic expandable yarn strands twisted together. The twisting adopts a 1+6+12 regular twisting. Water-blocking polyester tape is wrapped between the layers. The outermost gap of the outermost strand is filled with silicone elastomer water-blocking adhesive. Then, water-blocking polyester tape is wrapped around the outside of the watertight conductor.

[0008] The conductor insulation layer extruded outside the wrapped water-blocking polyester tape is compatible and bonded with the silicon-based elastomer water-blocking adhesive.

[0009] A water-blocking inner liner extruded over the conductor insulation layer;

[0010] An aramid fiber tensile braided layer is woven outside the water-blocking inner lining, and the gaps in the braided layer are filled with silicone-based elastomer water-blocking adhesive to form a longitudinal waterproof barrier, which is then wrapped with water-blocking polyester tape; and

[0011] The outermost waterproof sheath is squeezed in.

[0012] As an optional embodiment, the braiding angle of the aramid fiber tensile braided layer is 55±5°, and the braiding density is 90%±5%.

[0013] As an optional embodiment, the water-blocking liner is made of chlorosulfonated polyethylene or chloroprene rubber.

[0014] As an optional embodiment, the waterproof outer sheath is made of neoprene rubber, chlorosulfonated polyethylene, high-density polyethylene or polyether polyurethane.

[0015] As an optional embodiment, the hydrophilic expandable yarn and hydrophilic expandable yarn strands both use anionic polyacrylamide and a mixed graft of polyethylene glycol and crosslinking agent as the water-blocking matrix, and their water penetration length and water absorption expansion rate meet the requirements of the cable core:

[0016]

[0017] Wherein, L represents the water penetration length under pressure, in meters; ΔF is the longitudinal watertightness test pressure, in MPa; R0 is the inner radius of the water seepage channel, in mm; R1 is the outer radius of the water seepage channel, in mm; σ is the kinematic viscosity of water at 20℃, in MPa·S; ρ is the water absorption and expansion rate of the water-blocking matrix of the hydrophilic expandable yarn and hydrophilic expandable strand, in mm / s; k1 is the compressibility coefficient of the cable in the radial direction; and k2 is the stranding coefficient of the watertight conductor when stranded into a cable.

[0018] According to a second aspect of the present invention, a method for manufacturing a watertight power cable with a high current-carrying flexible portion is also provided, characterized by comprising the following steps:

[0019] First, based on the relationship between the cable's water penetration length and water absorption expansion rate, the cable core, and the required water penetration length, determine the design parameters for the cable core and the hydrophilic water-swellable polymer water-blocking matrix. Then, fabricate the cable according to the design parameters, specifically including the following steps:

[0020] Step 1: Twist together tin-plated copper monofilaments with seawater corrosion resistant hydrophilic expandable yarn and wrap them with a layer of water-blocking polyester tape to form a strand. The yarn and copper monofilaments are arranged in a cross pattern.

[0021] Step 2: Twist the strands together with the seawater corrosion resistant hydrophilic expandable yarn strands to form a watertight conductor. When twisting the watertight conductor, fill the outermost gap of the outermost strands with a silicone-based elastomer water-blocking adhesive that can withstand high temperatures of 125°C. Wrap the entire watertight conductor with a water-blocking polyester tape.

[0022] Step 3: Extrude the conductor insulation layer using 125℃ flexible ethylene propylene rubber;

[0023] Step 4: Extrude chlorosulfonated polyethylene or chloroprene rubber over the conductor insulation layer to form a water-blocking inner liner.

[0024] Step 5: Weave an aramid fiber tensile braided layer at a braiding angle of (55±5)° outside the water-blocking inner lining layer, with a braiding density of (90±5)%. Fill the gaps in the braided layer with a silicone-based elastomer water-blocking adhesive that is resistant to high temperature of 125°C to form a longitudinal waterproof barrier, and then wrap it with a water-blocking polyester tape.

[0025] Step 6: Finally, extrude neoprene rubber, chlorosulfonated polyethylene, high-density polyethylene or polyether polyurethane on the outermost layer to form a waterproof outer sheath.

[0026] The relationship between the water seepage length of the cable and the water absorption expansion rate, and the cable core, is as follows:

[0027]

[0028] Wherein, L represents the water penetration length under pressure, in meters; ΔF is the longitudinal watertightness test pressure, in MPa; R0 is the inner radius of the water seepage channel, in mm; R1 is the outer radius of the water seepage channel, in mm; σ is the kinematic viscosity of water at 20℃, in MPa·S; ρ is the water absorption and expansion rate of the water-blocking matrix of the hydrophilic expandable yarn and hydrophilic expandable strand, in mm / s; k1 is the compressibility coefficient of the cable in the radial direction; and k2 is the stranding coefficient of the watertight conductor when stranded into a cable.

[0029] As an optional embodiment, the water-blocking matrix is ​​an anionic, seawater salt ion-resistant, water-absorbing and swelling resin.

[0030] Based on the design of the above embodiments, the watertight power cable with a large current-carrying flexible section and its manufacturing method proposed in this invention overcome the drawback of the common practice of determining the longitudinal watertight performance of existing cables by verification after production. This invention proposes a method for calculating the water seepage length of a cable based on the predetermined pressure, structural dimensional parameters, and the expansion rate of a hydrophilic water-swellable waterproof material. This enables the design of a longitudinally watertight cable based on the calculation of the water seepage length using the expansion rate of the hydrophilic water-swellable polymer waterproof filling. Furthermore, a watertight power cable with a large current-carrying flexible section is proposed, achieving characteristics such as high current-carrying capacity (current-carrying capacity in seawater at 10℃ not less than 1000A), ultra-flexibility (minimum bending radius of 3 times the cable diameter), and watertightness for applications at a water depth of 650m. Simultaneously, the cable conductor has a flexible internal structure, and external water resistance achieves longitudinal watertightness. During termination assembly, the conductor is terminated as a whole to a watertight connector, achieving water resistance in application.

[0031] It should be understood that all combinations of the foregoing concepts and the additional concepts described in more detail below may be considered part of the inventive subject matter of this disclosure, provided that such concepts do not contradict each other. Furthermore, all combinations of the claimed subject matter are considered part of the inventive subject matter of this disclosure.

[0032] The foregoing and other aspects, embodiments, and features of the teachings of the present invention will be more fully understood from the following description in conjunction with the accompanying drawings. Other additional aspects of the invention, such as features and / or beneficial effects of exemplary embodiments, will become apparent from the following description or may be learned through practice of specific embodiments according to the teachings of the present invention. Attached Figure Description

[0033] The accompanying drawings are not intended to be drawn to scale. In the drawings, each identical or nearly identical component shown in the various figures may be denoted by the same reference numeral. For clarity, not every component is labeled in each figure. Embodiments of various aspects of the invention will now be described by way of example and with reference to the accompanying drawings.

[0034] Figure 1 This is a structural design drawing of a watertight power cable with a high current-carrying flexible portion according to an embodiment of the present invention. Detailed Implementation

[0035] To better understand the technical content of the present invention, specific embodiments are described below in conjunction with the accompanying drawings.

[0036] Various aspects of the invention are described in this disclosure with reference to the accompanying drawings, which illustrate numerous illustrative embodiments. The embodiments of this disclosure are not necessarily intended to encompass all aspects of the invention. It should be understood that the various concepts and embodiments described above, as well as those described in more detail below, can be implemented in any of many ways, because the concepts and embodiments disclosed herein are not limited to any particular implementation. Furthermore, some aspects of the invention disclosed may be used alone or in any suitable combination with other aspects of the invention disclosed.

[0037] {High Current-Carrying Flexible Watertight Power Cable}

[0038] Combination Figure 1 As shown, a watertight power cable with a high current-carrying flexible portion according to an example of the present invention includes:

[0039] The strand is composed of multiple conductor single wires 1 twisted together with hydrophilic expandable yarn and wrapped with water-blocking polyester tape 2, wherein the conductor single wires and hydrophilic expandable yarn are arranged in a cross pattern.

[0040] A watertight conductor composed of strands of yarn and hydrophilic expandable yarn filled together and twisted together, such as... Figure 1 As shown, the stranded strands are twisted in a 1+6+12 regular twisting manner, with water-blocking polyester tape 2 wrapped between the layers. The outermost gap of the outermost strand is simultaneously filled with silicone-based elastomer water-blocking adhesive 3, and then water-blocking polyester tape 2 is wrapped around the watertight conductor.

[0041] The conductor insulation layer 4, which is extruded outside the wrapped water-blocking polyester tape, is compatible and bonded to the silicon-based elastomer water-blocking adhesive.

[0042] A water-blocking inner liner 5 is extruded over the conductor insulation layer 4;

[0043] An aramid fiber tensile braided layer 6 is woven outside the water-blocking inner lining, and the gaps in the braided layer are filled with silicone-based elastomer water-blocking adhesive 3 to form a longitudinal waterproof barrier, which is then wrapped with a water-blocking polyester tape 2; and

[0044] 7. Extruded into the outermost waterproof outer sheath.

[0045] In embodiments of the present invention, the strand diameter ratio is 6 to 8 times, and the twisted diameter ratio of the watertight conductor is 7 to 9 times.

[0046] The aramid fiber tensile braided layer has a braiding angle of 55±5° and a braiding density of 90%±5%.

[0047] The water-blocking inner lining is made of chlorosulfonated polyethylene or chloroprene rubber.

[0048] The waterproof outer sheath is made of neoprene rubber, chlorosulfonated polyethylene, high-density polyethylene, or polyether polyurethane.

[0049] In embodiments of the present invention, both the hydrophilic expandable yarn and the hydrophilic expandable yarn strand use anionic polyacrylamide and a mixed graft of polyethylene glycol and a crosslinking agent as the water-blocking matrix. Through long-term research and experimentation by the applicant, it has been found that the water penetration length, water absorption expansion rate, and cable core of the cable satisfy the following:

[0050]

[0051] Wherein, L represents the water penetration length under pressure, in meters; ΔF is the longitudinal watertightness test pressure, in MPa; R0 is the inner radius of the water seepage channel, in mm; R1 is the outer radius of the water seepage channel, in mm; σ is the kinematic viscosity of water at 20℃, in MPa·S; ρ is the water absorption and expansion rate of the water-blocking matrix of the hydrophilic expandable yarn and hydrophilic expandable strand, in mm / s; k1 is the compressibility coefficient of the cable in the radial direction; and k2 is the stranding coefficient of the watertight conductor when stranded into a cable.

[0052] Therefore, this invention overcomes the drawback of the common practice of determining the longitudinal watertightness of cables by verification after production. By actively designing based on the above relationship, the proposed cable is based on the calculation of the seepage length according to the predetermined pressure, structural size parameters, and water absorption rate of the hydrophilic water-swellable water-blocking material. It meets the requirements of seepage-cable structure design under different environments and conditions. The watertight power cable with large current-carrying flexible part designed and prepared by this invention simultaneously achieves the characteristics of large current-carrying capacity (current-carrying capacity in seawater at 10℃ not less than 1000A), ultra-flexible (minimum bending radius is 3 times the cable diameter), and watertightness for application at a water depth of 650m. Moreover, the internal structure of the cable conductor is flexible, and the external water-blocking achieves longitudinal watertightness. During the termination assembly, the conductor is terminated as a whole to the watertight connector to achieve water-blocking in application.

[0053] {Preparation of high-current-carrying, flexible, watertight power cables}

[0054] In conjunction with the aforementioned design of a watertight power cable with a flexible, high-current-carrying portion, this invention also proposes a method for preparing the same watertight power cable with a flexible, high-current-carrying portion, comprising the following steps:

[0055] First, based on the relationship between the cable's water penetration length and water absorption expansion rate, the cable core, and the required water penetration length, determine the design parameters for the cable core and the hydrophilic water-swellable polymer water-blocking matrix. Then, fabricate the cable according to the design parameters, specifically including the following steps:

[0056] Step 1: Twist together tin-plated copper monofilaments with seawater corrosion resistant hydrophilic expandable yarn and wrap them with a layer of water-blocking polyester tape to form a strand. The yarn and copper monofilaments are arranged in a cross pattern.

[0057] Step 2: Twist the strands together with the seawater corrosion resistant hydrophilic expandable yarn strands to form a watertight conductor. When twisting the watertight conductor, fill the outermost gap of the outermost strands with a silicone-based elastomer water-blocking adhesive that can withstand high temperatures of 125°C. Wrap the entire watertight conductor with a water-blocking polyester tape.

[0058] Step 3: Extrude the conductor insulation layer using 125℃ flexible ethylene propylene rubber;

[0059] Step 4: Extrude chlorosulfonated polyethylene or chloroprene rubber over the conductor insulation layer to form a water-blocking inner liner.

[0060] Step 5: Weave an aramid fiber tensile braided layer at a braiding angle of (55±5)° outside the water-blocking inner lining layer, with a braiding density of (90±5)%. Fill the gaps in the braided layer with a silicone-based elastomer water-blocking adhesive that is resistant to high temperature of 125°C to form a longitudinal waterproof barrier, and then wrap it with a water-blocking polyester tape.

[0061] Step 6: Finally, extrude neoprene rubber, chlorosulfonated polyethylene, high-density polyethylene or polyether polyurethane on the outermost layer to form a waterproof outer sheath.

[0062] The relationship between the water seepage length of the cable and the water absorption expansion rate, and the cable core, is as follows:

[0063]

[0064] Wherein, L represents the water penetration length under pressure, in meters; ΔF is the longitudinal watertightness test pressure, in MPa; R0 is the inner radius of the water seepage channel, in mm; R1 is the outer radius of the water seepage channel, in mm; σ is the kinematic viscosity of water at 20℃, in MPa·S; ρ is the water absorption and expansion rate of the water-blocking matrix of the hydrophilic expandable yarn and hydrophilic expandable strand, in mm / s; k1 is the compressibility coefficient of the cable in the radial direction; and k2 is the stranding coefficient of the watertight conductor when stranded into a cable.

[0065] Among them, the water-blocking matrix is ​​anionic water-absorbing and swelling resin resistant to seawater salt ions, which has the characteristics of high water absorption rate, good water retention, heat resistance and stability, and good compatibility. When in contact with seawater, the swelling height and swelling rate change little.

[0066] {Example 1}

[0067] The conductor is made of tin-plated copper single wire with a diameter of (0.08±0.01) mm and seawater corrosion resistant hydrophilic expandable yarn twisted together to form a strand. The yarn and copper single wire are arranged in a cross pattern, and the twisting pitch ratio is (6 to 8).

[0068] The strands are twisted together with the seawater-resistant, corrosion-resistant, hydrophilic, and expandable yarn strand 2 to form a watertight conductor, with a twisting pitch ratio of (7-9) times.

[0069] The diameter of the seawater-resistant, hydrophilic, and expandable yarns and strands is 1.05 to 1.2 times the theoretically calculated diameter. When the watertight conductor is stranded, the outermost gap of the outermost strand is simultaneously filled with a high-temperature resistant (125℃) silicone-based elastomer water-blocking adhesive, and the entire watertight conductor is wrapped with a water-blocking polyester tape.

[0070] The insulation layer is made of 125℃ flexible ethylene propylene rubber, which is compatible with and bonded to silicone-based elastomer water-blocking adhesive.

[0071] The insulating outer extrusion is coated with a water-blocking inner liner of chlorosulfonated polyethylene or chloroprene rubber 5; the outer layer is woven with aramid fiber tensile braid at a braiding angle of (55±5)° and the braiding density is (90±5)%.

[0072] The braided external injection sealant is soft, high-temperature resistant, and water-resistant, with a hardness A of (15±5). During the injection process, an optical scanner provides closed-loop feedback control of the sealant flow to the pressure plate unloading machine and regulating valve, ensuring the sealant cavity is fully loaded and that the sealant always completely fills the conductor gaps, forming a longitudinal waterproof barrier.

[0073] A water-resistant polyester tape is wrapped around the woven layer. Then, a waterproof outer sheath made of neoprene rubber, chlorosulfonated polyethylene, high-density polyethylene, or polyether polyurethane is extruded over it.

[0074] Among them, the matrix of the water-blocking yarn fiber is a mixed graft of anionic polyacrylamide and polyethylene glycol, which are resistant to seawater salt ions and water-absorbing and swelling resin, and crosslinking agent. It has the characteristics of high water absorption, good water retention, heat resistance and stability, and good compatibility. When in contact with seawater, the swelling height and swelling rate change little.

[0075] The water-blocking properties of the water-blocking yarn fibers in laboratory seawater solutions conforming to VG 95214-4 and ASTM D 1141 standards are as follows: expansion rate not less than 16 mm / min, and expansion height not less than 18 mm after immersion in seawater solution for 5 min.

[0076] {Example 2}

[0077] The high-current-carrying, flexible, watertight power cable prepared according to the above method, with a diameter of 1*240mm... 2 and 1*185mm 2 Taking the design and measured watertight lengths of a high-current-carrying, ultra-flexible longitudinal watertight cable as an example, the design and test results are shown in Table 1 below:

[0078] Table 1 - Comparison of Test Results

[0079] Water pressure test pressure and time 6.5MPa, 6h 7MPa, 6h Span length 1.5m 1.5m Inner radius of the seepage channel 17.5mm 15.4mm Outer radius of the seepage channel 24.0mm 21.5mm Expansion rate of water-blocking filler material 16mm / s 16mm / s kinematic viscosity of water at 20°C <![CDATA[1.0×10 3 MPa·s]]> <![CDATA[1.0×10 3 MPa·s]]> Cable radial compression coefficient 0.1 0.1 Core stranding coefficient 1.03 1.03 Calculate the seepage length 0.25m 0.23m Measured seepage length 0.18m 0.17m

[0080] Therefore, it can be seen that the watertight power cable with large current-carrying flexible part designed and prepared by the present invention, based on the calculated water seepage length, and the actual test results show that the water seepage length is lower than the calculated water seepage length, which can meet and exceed the design requirements.

[0081] While the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the invention. Those skilled in the art can make various modifications and refinements without departing from the spirit and scope of the invention. Therefore, the scope of protection of the present invention shall be determined by the claims.

Claims

1. A watertight power cable with a high current-carrying flexible section, characterized in that, include: The strand is made of multiple conductor single wires twisted together with hydrophilic expandable yarn and wrapped with water-blocking polyester tape, wherein the conductor single wires and hydrophilic expandable yarn are arranged in a cross pattern. The watertight conductor is made of strands and hydrophilic expandable yarn strands twisted together. The twisting adopts a 1+6+12 regular twisting. Water-blocking polyester tape is wrapped between the layers. The outermost gap of the outermost strand is filled with silicone elastomer water-blocking adhesive. Then, water-blocking polyester tape is wrapped around the outside of the watertight conductor. The conductor insulation layer extruded outside the wrapped water-blocking polyester tape is compatible and bonded with the silicon-based elastomer water-blocking adhesive. A water-blocking inner liner extruded over the conductor insulation layer; An aramid fiber tensile braided layer is woven outside the water-blocking inner lining, and the gaps in the braided layer are filled with silicone-based elastomer water-blocking adhesive to form a longitudinal waterproof barrier, and then wrapped with water-blocking polyester tape. as well as Extruded into the outermost waterproof outer sheath; The hydrophilic expandable yarn and hydrophilic expandable yarn strands both use anionic polyacrylamide and a mixed graft of polyethylene glycol and crosslinking agent as the water-blocking matrix, and their water penetration length and water absorption expansion rate meet the requirements of the cable core: ； Where L represents the length of water penetration under pressure, in meters; This is the longitudinal watertightness test pressure, in MPa; It is the inner radius of the seepage channel, in mm; It is the outer radius of the seepage channel, in mm; It is the kinematic viscosity of water at 20°C, measured in MPa·s; is the water absorption and expansion rate of the water-blocking matrix of hydrophilic expandable yarn and hydrophilic expandable yarn strand, in mm / s; k1 is the compression coefficient of the cable in the radial direction; k2 is the stranding coefficient of the watertight conductor when stranded into a cable.

2. The watertight power cable with a high current-carrying flexible section according to claim 1, characterized in that, The twisting diameter ratio of the strands is 6 to 8 times.

3. The watertight power cable with a high current-carrying flexible section according to claim 1, characterized in that, The twisted section diameter ratio of the watertight conductor is 7 to 9 times.

4. The watertight power cable with a high current-carrying flexible section according to claim 1, characterized in that, The braiding angle of the aramid fiber tensile braided layer is 55±5°, and the braiding density is 90%±5%.

5. The watertight power cable with a high current-carrying flexible portion according to claim 1, characterized in that, The water-blocking inner lining is made of chlorosulfonated polyethylene or chloroprene rubber.

6. The watertight power cable with a high current-carrying flexible section according to claim 1, characterized in that, The waterproof outer sheath is made of neoprene rubber, chlorosulfonated polyethylene, high-density polyethylene, or polyether polyurethane.

7. A method for manufacturing a watertight power cable with a high current-carrying flexible portion according to any one of claims 1-6, characterized in that, The preparation method Includes the following steps: First, based on the relationship between the cable's water penetration length and water absorption expansion rate, the cable core, and the required water penetration length, determine the design parameters for the cable core and the hydrophilic water-swellable polymer water-blocking matrix. Then, fabricate the cable according to the design parameters, specifically including the following steps: Step 1: Twist together tin-plated copper monofilaments with seawater corrosion resistant hydrophilic expandable yarn and wrap them with a layer of water-blocking polyester tape to form a strand. The yarn and copper monofilaments are arranged in a cross pattern. Step 2: Twist the strands together with the seawater corrosion resistant hydrophilic expandable yarn strands to form a watertight conductor. When twisting the watertight conductor, fill the outermost gap of the outermost strands with a silicone-based elastomer water-blocking adhesive that can withstand high temperatures of 125°C. Wrap the entire watertight conductor with a water-blocking polyester tape. Step 3: Extrude the conductor insulation layer using 125℃ flexible ethylene propylene rubber; Step 4: Extrude chlorosulfonated polyethylene or chloroprene rubber over the conductor insulation layer to form a water-blocking inner liner. Step 5: Weave an aramid fiber tensile braided layer at a braiding angle of (55±5)° outside the water-blocking inner lining layer, with a braiding density of (90±5)%; fill the gaps in the braided layer with a silicone-based elastomer water-blocking adhesive that is resistant to high temperature of 125°C to form a longitudinal waterproof barrier, and then wrap it with a water-blocking polyester tape. Step 6: Finally, extrude neoprene rubber, chlorosulfonated polyethylene, high-density polyethylene or polyether polyurethane on the outermost layer to form a waterproof outer sheath. The relationship between the water seepage length of the cable and the water absorption expansion rate, and the cable core, is as follows: ； Where L represents the length of water penetration under pressure, in meters; This is the longitudinal watertightness test pressure, in MPa; It is the inner radius of the seepage channel, in mm; It is the outer radius of the seepage channel, in mm; It is the kinematic viscosity of water at 20°C, measured in MPa·s; is the water absorption and expansion rate of the water-blocking matrix of hydrophilic expandable yarn and hydrophilic expandable yarn strand, in mm / s; k1 is the compression coefficient of the cable in the radial direction; k2 is the stranding coefficient of the watertight conductor when stranded into a cable.

8. The method for preparing a watertight power cable with a high current-carrying flexible portion according to claim 7, characterized in that, The water-blocking matrix is ​​an anionic, seawater salt ion resistant, water-absorbing and swelling resin.

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