Submarine cable with unequal-diameter conductors and manufacturing method thereof

Abstract

The invention discloses a submarine cable with unequal-diameter conductors and a manufacturing method of the submarine cable, and relates to submarine cables. The current submarine cable has the defects of weak current-carrying capacity of a landing section, poor heat dissipation condition and unstable overall operation performance of the cable. The cable comprises a first cable used for a sea middle section and a second cable used for a landing section. The conductor diameter of the second cable is greater than that of the first cable; the first cable and the second cable are connected into a whole submarine cable in an integral manufacturing or butt joint mode; the integrally manufactured submarine cable is directly produced and processed in the subsequent process of a cable production line after the difference value of the conductor diameters of the first cable and the second cable is reduced to a set threshold value in the conductor twisting link; the first cable and the second cable which are in butt joint are independently produced and manufactured and are connected in a conductor staggered-layer welding mode. According to the technical scheme, the large conductor is adopted in the landing section, the current-carrying capacity of the landing section is effectively improved, and the problems that the landing section is poor in heat dissipation condition and high in temperature rise are solved.

Description

Technical Field

[0001] The present invention relates to submarine cables, and particularly to a submarine cable with unequal-diameter conductors and a manufacturing method thereof. Background Art

[0002] In recent years, with the construction of offshore wind power and island power supply projects, the number of submarine cable lines has gradually increased. Submarine cable lines are usually more than ten kilometers or even dozens of kilometers long. Most of the submarine cable lines are in seawater below the sea level or buried under the seabed, which is called the mid-sea section. The landing section of the submarine cable line refers to the part that gradually emerges from the seawater to reach the land, usually including the intertidal zone (submerged by seawater during high tide and exposed during low tide) and the onshore section.

[0003] The environmental differences between the mid-sea section and the landing section are significant. The environmental temperature and heat dissipation conditions around the submarine cable in the mid-sea section are different from those in the landing section. Relevant research and test results show that the environment in the landing section of the submarine cable is complex, with a higher temperature and being greatly affected by the seawater and air temperature. The heat dissipation condition in the landing section is poor, resulting in a higher temperature rise, which becomes the bottleneck of the current-carrying capacity of the entire submarine cable line. Therefore, during the design and operation of the submarine cable line, the temperature rise and transmission capacity in the landing section are mainly concerned, especially the demand for emergency current-carrying capacity.

[0004] To improve the current-carrying capacity of the submarine cable line, especially in the landing section, usually the cross-section of the conductor of the entire submarine cable is designed based on the landing section, which leads to an excessive current-carrying capacity in the mid-sea section, increases the investment in the overall cable line, and reduces the cost performance. To improve the current-carrying capacity of the landing section, some research and engineering applications have tried to take measures, such as removing the cable armor layer on the onshore part of the landing section to improve the heat dissipation capacity, but the improvement effect is still limited. Therefore, how to effectively improve the current-carrying capacity in the landing section during the design and manufacturing process has become the key to improving the current-carrying capacity and safe operation of the entire submarine cable line. Summary of the Invention

[0005] The technical problem to be solved and the technical task proposed by the present invention are to improve and perfect the existing technical solution, and provide a submarine cable with unequal-diameter conductors and a manufacturing method thereof, so as to achieve the purpose of improving the current-carrying capacity and cost performance of the overall line by optimizing the design of the landing section of the submarine cable. For this purpose, the present invention adopts the following technical solutions.

[0006] A submarine cable with unequal-diameter conductors includes a first cable for the mid-sea section and a second cable for the landing section; the conductor diameter of the second cable is larger than that of the first cable; the first cable and the second cable are connected into a whole submarine cable by integral manufacturing or butt joint; The integrally manufactured submarine cable is directly produced and processed in the subsequent processes of the cable production line after reducing the difference in the conductor diameters of the first cable and the second cable to a set threshold value during the conductor stranding process. The conductor shielding layer, insulation layer, and insulation shielding layer on the outer periphery of the conductor are completed by three-layer co-extrusion on the production line; The butt-jointed submarine cable is separately produced and manufactured for the first cable and the second cable, and the conductors of the first cable and the second cable are connected by conductor staggered-layer welding, and the respective structural layers on the outer side of the cable conductor are restored at the connection point.

[0007] By adopting a larger conductor diameter in the landing section in this technical solution, the current-carrying capacity of this section can be effectively improved, and the problems of poor heat dissipation conditions and high temperature rise in the landing section can be solved.

[0008] By connecting the cables in the mid-sea section and the landing section by adopting the integrally manufactured or butt-jointed method according to actual needs, the design redundancy caused by too large conductors in the mid-sea section is avoided, thereby reducing the investment cost of the overall submarine cable line.

[0009] The integrally manufactured and butt-jointed production methods can be flexibly selected according to the size of the difference in conductor diameters, ensuring the adaptability and efficiency of production.

[0010] Through the design of conductor staggered-layer welding and restoration of the structural layer, a smooth transition at the connection part is ensured, enhancing the mechanical strength and long-term use stability of the cable.

[0011] As a preferred technical measure: the difference in the conductor cross-sectional areas of the first cable and the second cable of the integrally manufactured submarine cable is less than 100 mm²; in the conductor stranding process of the integrally manufactured submarine cable, the difference in conductor diameters is reduced to a value that can be directly produced and processed subsequently by replacing single wires with different diameters and / or adjusting the compaction coefficient.

[0012] By controlling the difference in conductor diameters, conductors with different diameters can be directly processed in the subsequent production and processing, avoiding complex subsequent trimming processes or additional processing steps, thereby simplifying the production process and reducing the manufacturing cost. By adjusting the compaction coefficient or replacing single wires with different diameters, the structure of the conductor becomes more compact and uniform, reducing stress concentration inside the conductor and improving the mechanical strength and reliability of the cable.

[0013] As a preferred technical measure: for the butt-jointed submarine cable with the difference in the conductor cross-sectional areas of the first cable and the second cable less than 100 mm², the conductor transition area is welded in layers using conductors with the same number of layers and different single-wire diameters, and the difference in the diameters of the conductor single wires decreases layer by layer from the outside to the inside, and the difference in the single-wire diameters of each layer does not exceed 10%.

[0014] By using conductors with the same number of layers and different single-wire diameters in the conductor transition area for layered welding, the diameter difference of the conductors decreases layer by layer, which can effectively avoid the stress concentration phenomenon caused by large diameter differences, thereby reducing the mechanical stress and thermal stress in the conductor transition area and improving the overall stability and service life of the cable.

[0015] The design of the decreasing single-wire diameter layer by layer optimizes the conductivity and thermal conductivity of the conductor, which helps the heat of the cable to dissipate quickly. Especially under high current-carrying conditions, it can effectively reduce the cable temperature rise and improve the safe operation ability of the cable.

[0016] Through layered welding and the decreasing single-wire diameter layer by layer, the thermal stress distribution in the welded conductor transition area is more uniform, which helps to ensure the welding quality and avoid the risk of fragile or insecure connections at the welding part due to excessive conductor diameter differences, thereby improving the reliability and mechanical strength of the cable.

[0017] The design of using the same number of layers and different single-wire diameters simplifies the welding operation during the manufacturing process, reduces the requirements for operation accuracy, thereby improving production efficiency, and also reduces the situation of reprocessing due to improper welding.

[0018] Through the layered welding and the design of the decreasing single-wire diameter layer by layer, the cable can have stronger adaptability when facing changes in different environmental temperatures, current-carrying capacities, and physical conditions. It is especially suitable for the conductor transition area of long-distance submarine cables, ensuring that the cable can withstand large temperature differences and load changes and extending the service life of the cable.

[0019] The structure of the overall cable is more balanced, especially at the conductor connection part, ensuring the electrical conductivity, thermal management ability, and mechanical durability of the cable, and ultimately improving the overall performance and reliability of the cable.

[0020] As a preferred technical means: for butt-jointed submarine cables with a conductor cross-section difference greater than 100 mm² and less than or equal to 500 mm², the conductor transition area is butt-jointed by using conductors with different numbers of layers and the same single-wire diameter for layered welding layer by layer, and the first cable and the second cable are connected by staggered-layer welding of the conductors; For butt-jointed submarine cables with a conductor cross-section difference greater than 100 mm² and less than 200 mm², the conductor transition area adopts a structure with a difference of 1 layer. For butt-jointed submarine cables with a conductor cross-section difference greater than 200 mm² and less than 500 mm², the conductor transition area adopts a structure with a difference of 2 layers. The welding angle of the welded conductor transition area is not greater than 15°.

[0021] By adopting structures with different numbers of layers (such as a difference of 1 layer or 2 layers) to adapt to the change in the difference of the conductor cross-sections, the mechanical properties and electrical properties of the conductor can be better balanced, ensuring a smoother connection in the conductor transition area. By adjusting the number of layers in the conductor transition area, the stress concentration caused by the difference in the conductor cross-sections can be effectively reduced, and the thermal stress and mechanical stress at the welding part can be lowered, thereby enhancing the long-term reliability of the cable.

[0022] The staggered welding of conductors not only improves the mechanical properties of the connection part but also effectively avoids problems such as structural non-uniformity and stress concentration caused by excessive differences in the conductor cross-sections. This staggered welding helps the stability of the cable during long-term operation and reduces the impact of factors such as external environmental changes and temperature fluctuations on the cable.

[0023] Specifying that the angle of the welded conductor transition area is not greater than 15° can ensure a smoother connection between the conductors, avoid sharp changes or imbalances in the conductor transition area, reduce the adverse effects on the mechanical and electrical properties of the cable, and enhance the strength and durability of the welding part.

[0024] Through a reasonable layered structure and staggered welding, the conductor transition area can better balance the current distribution between the conductors, reduce local heating caused by poor contact, and at the same time, by optimizing the heat conduction performance of the conductor transition area, help the cable dissipate heat effectively, reduce the temperature rise, and avoid cable damage caused by excessive temperature.

[0025] As a preferred technical means: for the butt joint submarine cable with a difference in the conductor cross-section greater than 500 mm², the conductor transition area uses conductors with different numbers of layers and different single wire diameters for layer-by-layer connection, and at least two layers of welding transition structures are used for welding, and the angle of the welded conductor transition area is not greater than 15°.

[0026] When the difference in the conductor cross-section is greater than 500 mm², by using conductors with different numbers of layers and different single wire diameters for layer-by-layer connection, the connection difficulties caused by large cross-section differences can be effectively alleviated. The layer-by-layer connection method can better balance the mechanical stress and current distribution between the conductors, thereby avoiding problems such as stress concentration, poor conductivity, or heat loss caused by excessive cross-section differences.

[0027] By using at least two layers of welding transition structures in the conductor transition area, not only can a smooth transition at the conductor connection be ensured, reducing the risk of poor contact, but also the mechanical strength of the welding area can be improved. The design of gradually transitioning layer by layer helps reduce thermal stress and structural non-uniformity, enhancing the durability of the cable and its ability to resist the external environment.

[0028] The method of welding conductors layer by layer can effectively control the temperature distribution in the conductor transition zone and reduce the local overheating phenomenon caused by excessive differences in conductor cross-sections. Especially when the difference in conductor cross-sections is large, using layered connection can better dissipate heat, avoid excessive local temperature rise, thereby improving the heat dissipation performance of the cable and reducing the impact of temperature on the cable.

[0029] Specifying that the angle of the welded conductor transition zone is not greater than 15° can ensure a smoother and more natural connection between conductors. Such a design can reduce stress concentration in the conductor transition zone, making the cable more stable during operation and avoiding material stress concentration or fracture caused by too large an angle.

[0030] By adopting the design of layer-by-layer connection and reasonably controlling the welding angle, the high-cost requirements caused by excessive differences in conductor cross-sections can be reduced. This method can optimize the production process without reducing the cable performance, thereby reducing the manufacturing cost and improving the cost performance of the product.

[0031] As a preferred technical measure: The conductor shielding layer, insulation layer, and insulation shielding layer of the first cable and the second cable for butt-joining submarine cables are connected from the inside out respectively, where the angle of the conductor shielding layer transition zone is not greater than 12°, the angle of the insulation layer transition zone is not greater than 8°, and the angle of the insulation shielding layer transition zone is not greater than 5°.

[0032] By specifying the angle limits of the conductor shielding layer, insulation layer, and insulation shielding layer transition zones, it helps to ensure a smooth transition between the layer structures. This design reduces stress concentration in each layer transition zone, avoids material yielding, cracking, or thermal damage caused by too large an angle, and thus improves the mechanical strength and service life of the cable.

[0033] Controlling the transition zone angle can improve the electrical performance of the conductor shielding layer, insulation layer, and insulation shielding layer. A smaller transition angle can effectively reduce signal interference, electrical leakage, and uneven electric field distribution, and enhance the transmission stability and reliability of the cable.

[0034] In submarine cables, controlling the angle of each layer transition zone helps the cable to be used for a long time in a complex environment. Especially considering that submarine cables are exposed to environmental factors such as seawater, tidal changes, and temperature fluctuations, it can significantly reduce the risk of cable aging and damage caused by stress concentration in the transition zone, thereby enhancing the durability and environmental erosion resistance of the cable.

[0035] Controlling the angle of each layer transition zone of the cable helps the stability of the cable during long-term use, reduces the occurrence of faults caused by unreasonable transition zone structures, and thus reduces the maintenance frequency and cost. Especially in the application of submarine cables, reducing the need for cable inspection and repair can improve the reliability of the submarine cable system and extend the service life.

[0036] By reasonably controlling the transition angles of each layer structure, the impact and stress transfer between the cable structure layers can be reduced, the mutual interference between the conductor layer and the outer sheath layer can be avoided, and the mechanical and electrical properties of the overall cable can be improved. A good transition zone design can enhance the working ability of the cable under various working conditions without increasing extra weight and cost.

[0037] Another object of the present invention is to provide a manufacturing method for a submarine cable with unequal-diameter conductors. The manufacturing method of the submarine cable includes the following steps: 1) Design the conductor diameters respectively according to the environmental factors and load requirements of the mid-sea section and the landfall section to obtain the first cable conductor diameter for the mid-sea section and the second cable conductor diameter for the landfall section; 2) Judge the difference between the first cable conductor diameter and the second cable conductor diameter. If the difference is less than the first set value, the submarine cable is manufactured by an integral or butt joint method; if the difference is greater than the first set value, the submarine cable is manufactured by a butt joint method; 3) When adopting the integral manufacturing method, during the conductor stranding process, adjust the diameter difference of the conductors so that the diameter difference between the two sections of conductors is less than the set threshold value, and directly process in the subsequent processes of the cable production line. The structural layer including the conductor shielding layer, the insulating layer and the insulation shielding layer wrapped outside the conductor is formed by coextrusion technology; 4) When adopting the butt joint manufacturing method, first manufacture the first cable for the mid-sea section and the second cable for the landfall section separately, and then connect the two sections of conductors by conductor staggered-layer welding to ensure a smooth transition at the connection part, and gradually restore the outer structure layer of the cable.

[0038] By designing the conductor diameters respectively according to the environmental factors and load requirements of the mid-sea section and the landfall section, targeted optimization can be achieved, enabling the cable to fully exert its performance under different working environments and ensuring the reliability and stability of the submarine section and the landfall section.

[0039] By adjusting the diameter difference of the conductors in the conductor stranding link, the integral manufacturing method can achieve a smooth transition between the conductors, thereby improving the electrical performance of the cable and ensuring the temperature rise control and heat dissipation effect of the cable under high current-carrying capacity.

[0040] For the two manufacturing methods of integral manufacturing and butt joint manufacturing, the appropriate process can be flexibly selected according to the size of the diameter difference of the conductors. This can optimize the connection method between different cable sections while ensuring production flexibility and reducing the complexity in the production process.

[0041] Through the integral manufacturing method, the diameter difference of the conductors can be optimized by adjusting the stranding process during the production process, avoiding the complexity of butt joint manufacturing, thereby reducing the production cost. At the same time, the integral manufacturing method can also reduce the transmission loss of the cable and improve the economy of the cable.

[0042] When using the butt joint method, two sections of conductors are connected by staggered welding of conductors, which can ensure a smooth transition at the connection part and reduce electrical problems caused by poor connection. At the same time, the outer sheath structure layer of the cable is restored layer by layer to ensure the mechanical strength and electrical performance of the connection part and avoid the occurrence of poor contact or insulation damage.

[0043] Reasonable conductor design and manufacturing process can effectively reduce the influence of environmental factors (such as seawater temperature, pressure, tides, etc.) on the cable and ensure the stability and safety of the cable during long-term operation.

[0044] Adopting reasonable manufacturing processes and high-quality connection structures can improve the durability and environmental damage resistance of the cable, reduce the maintenance frequency and repair costs. In the application of submarine cables, reducing the failure rate and repair difficulty are important advantages.

[0045] Design and manufacture suitable cables according to the different environmental requirements of the mid-sea section and the landing section to ensure the stable operation of the cable under changing marine environments and different temperature, humidity, and load conditions, and improve the market adaptability of the product.

[0046] As an optimal technical means: the first set value is 100 mm²; when manufacturing a submarine cable with a conductor diameter difference less than 100 mm² by the integral method, the difference in conductor diameter is reduced to a value that can be directly produced and processed subsequently by replacing single wires of different diameters and / or adjusting the compaction coefficient during the conductor stranding process; When manufacturing a submarine cable with a conductor diameter difference less than 100 mm² by the butt joint method, the conductor transition area is welded in layers using conductors with the same number of layers and different single wire diameters. The diameter difference of the conductor single wires decreases layer by layer from the outside to the inside, and the diameter difference of the single wires in each layer does not exceed 10%.

[0047] By adjusting the difference in conductor diameter during the conductor stranding process, the integral manufacturing method can ensure a smooth transition between conductors, thereby reducing the electrical loss and temperature rise at the conductor connection part and improving the electrical conductivity and stability of the cable.

[0048] The integral manufacturing method adjusts the difference in conductor diameter, enabling the conductors to achieve the best match during the production process, reducing possible adaptation problems in subsequent processing, optimizing the production process, and improving production efficiency.

[0049] When using the butt joint method, through the process of layered welding, the conductor transition area becomes smoother, avoiding problems such as electrical defects or insufficient mechanical strength caused by direct connection, and ensuring the stability and long-term reliability of the connection.

[0050] In the butt joint method, conductors with different single wire diameters are used for layered welding, and it is ensured that the difference in single wire diameters of each layer does not exceed 10%. This can, while ensuring the stability and electrical conductivity of the cable, meet the connection requirements of conductors with different diameter differences.

[0051] The overall manufacturing method is applicable to the case where the difference in conductor diameters is small, making the cable more efficient in the manufacturing process, reducing costs, and improving the cost performance of the cable.

[0052] As a preferred technical means: when the cross-sectional area difference of the conductors is greater than 100 mm² and less than or equal to 500 mm², conductors with different numbers of layers and the same single wire diameter are used for butt joint by means of layer-by-layer welding, and the first cable and the second cable are connected by staggered layer welding of the conductors; For the case where the cross-sectional area difference is greater than 100 mm² and less than 200 mm², a structure with a difference of 1 layer is adopted, and for the case where the cross-sectional area difference is greater than 200 mm² and less than 500 mm², a structure with a difference of 2 layers is adopted; the angle of the welding conductor transition zone is not greater than 15°; When the cross-sectional area difference of the conductors is greater than 500 mm², conductors with different numbers of layers and different single wire diameters are used for layer-by-layer connection, and at least two layers of welding transition structures are used for welding, and the angle of the welding conductor transition zone is not greater than 15°.

[0053] By selecting different numbers of welding layers and single wire diameters according to the size of the cross-sectional area difference of the conductors, it is ensured that the conductors can have a smooth transition during the connection process, avoiding problems such as unstable electrical performance or poor contact caused by too large a diameter difference.

[0054] For cables with different cross-sectional area differences of conductors, the scheme provides a flexible adjustment method. When the cross-sectional area difference of the conductors is small (such as 100 mm² to 200 mm²), fewer transition layers (1 layer) are adopted, while when the cross-sectional area difference is large (such as 200 mm² to 500 mm²), more transition layers (2 layers) are adopted to ensure the best connection effect in each case. For larger differences (>500 mm²), conductors with different numbers of layers and different single wire diameters are used to further optimize the connection structure to ensure the stability of the connection part.

[0055] The layer-by-layer welding method can reduce the electrical defects in the conductor transition zone, such as current concentration or hot spot problems, through layered transition, improve the overall electrical conductivity and stability of the cable, and reduce the current loss and temperature rise at the conductor joint.

[0056] The angle of the welding conductor transition zone is not greater than 15°, which can effectively reduce the stress concentration problem at the joint, thereby reducing the fatigue damage of the cable during long-term operation and increasing the service life and reliability of the cable.

[0057] According to the differences in the cross-sectional areas of conductors, this technical solution flexibly adjusts the welding structure, which can not only adapt to the situation of small cross-sectional area differences but also handle the complex connection requirements of larger differences, enhancing the adaptability of cable production.

[0058] By adopting a differential layer structure in the case of different cross-sectional area differences, unnecessary complex processes can be reduced while ensuring the cable performance, thus reducing the manufacturing cost.

[0059] The design of different layers enables the cable joints to distribute pressure more evenly, reducing the tensile and compressive stresses at the joints, which helps to improve the tensile strength and compressive capacity of the cable under high-load operating conditions.

[0060] By controlling the changes in the diameter of the single conductor wires and the number of layers, the quality of each welding connection is ensured to be consistent, reducing the human error during the welding process, thereby enhancing the overall quality control level of the cable products.

[0061] This technical solution is particularly suitable for use in special environments such as submarine cables. These environments require the cable to have extremely high mechanical strength, conductivity, and stability, especially when operating in complex marine environments, and it can effectively cope with harsh conditions such as seawater and temperature changes.

[0062] As a preferred technical means: the conductor shielding layer, insulation layer, and insulation shielding layer of the first cable and the second cable connected to the submarine cable are connected from the inside to the outside respectively, where the angle of the transition area of the conductor shielding layer is not greater than 12°, the angle of the transition area of the insulation layer is not greater than 8°, and the angle of the transition area of the insulation shielding layer is not greater than 5°. Beneficial effects: By adopting a larger conductor diameter in the landing section, this technical solution can effectively improve the current-carrying capacity of this section and solve the problems of poor heat dissipation conditions and high temperature rise in the landing section.

[0063] By connecting the cables in the mid-sea section and the landing section by integral manufacturing or butt joint according to actual needs, the design redundancy caused by an overly large conductor in the mid-sea section is avoided, thereby reducing the investment cost of the overall submarine cable line.

[0064] Two different production methods, integral manufacturing and butt joint, can be flexibly selected according to the size of the difference in conductor diameters, ensuring the adaptability and efficiency of production.

[0065] Through the design of conductor staggered welding and the restoration of the structural layer, a smooth transition of the connection part is ensured, enhancing the mechanical strength and long-term use stability of the cable. Description of the Drawings

[0066] Figure 1 is the cross-sectional view of the conductor of the present invention.

[0067] Figure 2 is the schematic diagram of the first conductor butt joint structure of the present invention.

[0068] Figure 3 It is a schematic diagram of the second conductor butt joint structure of the present invention.

[0069] Figure 4 It is a schematic diagram of the restoration of the first conductor shielding layer of the present invention.

[0070] Figure 5 It is the restoration diagram of the second conductor shielding layer of the present invention.

[0071] In the figure: 1. First cable; 2. Second cable; 3. Conductor; 301. Single wire; 4. Conductor transition area; 5. Conductor shielding layer; 6. Large conductor; 7. Small conductor; 8. Conductor shielding layer transition area. Specific implementation mode

[0072] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings of the specification.

[0073] Embodiment 1: Provide a submarine cable with unequal-diameter conductors, which includes a first cable 1 for the sea section and a second cable 2 for the landing section; the diameter of the conductor 3 of the second cable 2 is larger than the diameter of the conductor 3 of the first cable 1; the first cable 1 and the second cable 2 are connected into a whole submarine cable by means of integral manufacturing or butt joint.

[0074] The integrally manufactured submarine cable is directly produced and processed in the subsequent processes of the cable production line after reducing the difference in the diameters of the conductors 3 of the first cable 1 and the second cable 2 to a set threshold value during the conductor stranding process, and the conductor shielding layer 5, insulating layer and insulating shielding layer outside the conductor 3 are completed by means of three-layer coextrusion on the production line.

[0075] The butt-jointed submarine cable is separately produced and manufactured for the first cable 1 and the second cable 2, and the conductors 3 of the first cable 1 and the second cable 2 are connected by means of staggered welding of the conductors 3, and the respective structural layers outside the cable conductor 3 are restored at the connection.

[0076] In this technical solution, by adopting a larger conductor 6 diameter in the landing section, the current-carrying capacity of this section can be effectively improved, and the problems of poor heat dissipation conditions and high temperature rise in the landing section can be solved.

[0077] By connecting the cables in the sea section and the landing section by means of integral manufacturing or butt joint according to actual needs, the design redundancy caused by too large a conductor 3 in the sea section is avoided, thereby reducing the investment cost of the overall submarine cable line.

[0078] The two different production methods of integral manufacturing and butt joint can be flexibly selected according to the size of the difference in the diameters of the conductors 3, ensuring the adaptability and efficiency of production.

[0079] Through the design of staggered welding of the conductor 3 and restoration of the structural layer, a smooth transition at the connection part is ensured, enhancing the mechanical strength and long-term use stability of the cable.

[0080] The present invention adopts a segmented design for the conductor 3 of the submarine cable line according to the characteristics of the submarine cable route, in combination with positions such as local overheating points and submarine cable landing sections in the submarine cable route. That is, on the premise of meeting the current-carrying capacity, small-conductor 7-section submarine cables are used in the middle section of the submarine cable line, and large-conductor 3-section submarine cables matching the environmental characteristics of the landing sections are used at both ends of the submarine cable line. The small-conductor 7-section and large-conductor 3-section submarine cables are connected in a laying ship or a submarine cable manufacturing factory, and each structural layer of the submarine cable is restored layer by layer.

[0081] The submarine cable conductor 3 usually adopts a compact round layered conductor 3 structure as shown in Figure 1 . Therefore, the connection of large and small cross-sections can be carried out by the method of layer-by-layer welding. Therefore, a correlative structural design is required for the single-wire 301 diameter and the number of layers of the conductor 3 of the large-conductor 6-section submarine cable and the small-conductor 7-section submarine cable docked by this method. Here, the large-conductor 6-section submarine cable is the second cable 2, and the small-conductor 7-section submarine cable is the first cable 1.

[0082] According to the difference between the large-conductor 6-section and the small-conductor 7-section, 3 forms are determined, less than 100 mm 2 , greater than 100 mm 2 less than or equal to 500 mm 2 , greater than 500 mm 2 .

[0083] Corresponding to the conductor 3 cross-section differences of the three forms, the manufacturing methods of the large and small cross-section connecting cables can be divided into two types: Method 1 (overall manufacturing method) - when the conductor 3 cross-section difference is less than 100 mm 2 , the difference in the conductor 3 diameter can be reduced to be suitable for direct production and processing in the subsequent processes of the cable production line by replacing single wires 301 of different diameters and adjusting the compaction coefficient during the conductor stranding link.

[0084] Method 2 (docking method) - when the conductor 3 cross-section difference is greater than 100 mm 2 less than or equal to 500 mm 2 and the conductor 3 cross-section difference is greater than 500 mm 2 , the large and small conductor 7-section cables are separately manufactured, and then the large and small cross-section conductors 3 are connected by the method of staggered welding of the conductor 3, and each structural layer of the cable is restored layer by layer at the connection.

[0085] Main structural design and manufacturing method: (I) Conductor connection design Form 1 - The cross-sectional difference of the conductor 3 is less than 100 mm 2 When this is the case, conductors 3 with the same number of layers but different diameters of individual wires 301 can be used for layered welding. Design by adjusting the diameters of the individual wires 301 in different layers to meet the cross-sectional difference. Usually, first change the diameter of the outermost individual wire 301, and adopt the method of changing layer by layer from the outermost layer to the innermost layer. The difference in the diameters of the individual wires 301 is not greater than 10%.

[0086] Form 2 - The cross-sectional difference of the conductor 3 is greater than 100 mm 2 Less than 500 mm 2 When this is the case, conductors 3 with different numbers of layers but the same diameter of individual wires 301 can be used for layered welding. The outermost conductor 3 of the large conductor 6 cross-section is connected to the outermost layer of the conductor 3 of the small conductor 7 cross-section after treatment, and pay attention to staggering the connection positions of the same layer. At the same time, for the cross-sectional difference greater than 100 mm 2 Less than 200 mm 2 When this is the case, a structure with a difference of 1 layer can be adopted, as shown in Figure 2 As shown. When the cross-sectional difference is greater than 200 mm 2 Less than 500 mm 2 When this is the case, a structure with a difference of 2 layers can be adopted, as shown in Figure 3 As shown. For the structures with a difference of 1 layer and a difference of 2 layers, the length of the conductor transition zone 4 should be appropriately adjusted to control the angle of the conductor transition zone 4 for layered welding not to be greater than 15°. The angle can be adjusted by adjusting the length of the conductor transition zone 4.

[0087] Form 3 - The cross-sectional difference of the conductor 3 is greater than 500 mm 2 When this is the case, conductors 3 with different numbers of layers and different diameters of individual wires 301 can be used for layered connection. A welding structure with a difference of 2 layers or more than 3 layers of conductors 3 is adopted. The length of the conductor transition zone 4 should be appropriately adjusted to control the angle of the conductor transition zone 4 for layered welding not to be greater than 15°.

[0088] (2) Shield and insulation layer connection Form 1 - The conductor shield layer 5, insulation layer and insulation shield layer are completed by three-layer coextrusion on the production line.

[0089] Form 2 - First, restore the conductor shield layer of the conductor shield layer transition zone 8, so that the restored conductor shield layer is well connected to the conductor shield layer 5 of the cable of the small conductor 7 cross-section and the conductor shield layer 5 of the cable of the large conductor 6 cross-section respectively; due to the existence of a certain slope, when restoring the conductor shield layer, on the premise of ensuring better thickness uniformity of the conductor shield layer, the thickness of the restored conductor shield layer in the transition zone connected to the conductor shield layer of the cable of the small conductor 7 cross-section should be appropriately increased, as shown in Figure 4 、 Figure 5 As shown, to reduce the angle of the transition zone so that it does not exceed 12°.

[0090] The insulation layer is restored. Using a grinding tool, under certain temperature and cleanliness requirements, an insulating material is injected to form it, and heat preservation and pressure holding measures are taken to ensure reliable connection between the restored insulation layer and the body insulation layer. By trimming the outer surface of the restored insulation, the angle of the transition zone is further reduced to no more than 8°.

[0091] Further, an insulation shielding layer is restored outside the insulation layer. On the premise of ensuring good thickness uniformity of the insulation shielding layer, the thickness of the insulation shielding layer in the transition zone connected to the insulation shielding layer of the small-conductor 7-section cable should be appropriately increased to further reduce the angle of the transition zone to no more than 5°.

[0092] The restoration of other structural layers is the same as the joint process of submarine cable engineering and will not be elaborated here.

[0093] Embodiment 2: A manufacturing method of a submarine cable with unequal-diameter conductors, which includes the following steps: S1: Design the diameters of the conductors 3 according to the environmental factors and load requirements of the mid-sea section and the onshore section respectively, to obtain the diameter of the conductor 3 of the first cable 1 for the mid-sea section and the diameter of the conductor 3 of the second cable 2 for the landing section.

[0094] S2: Judge the difference between the diameter of the conductor 3 of the first cable 1 and the diameter of the conductor 3 of the second cable 2. If the difference is less than the first set value, the submarine cable is manufactured by an integral or butt joint method; if the difference is greater than the first set value, the submarine cable is manufactured by a butt joint method.

[0095] In this embodiment, the first set value is 100 mm².

[0096] When adopting the integral manufacturing method, by adjusting the diameter difference of the conductor 3 during the stranding process of the conductor 3, the diameter difference between the two sections of the conductor 3 is made less than the set threshold, and direct processing is carried out in the subsequent processes of the cable production line. The structural layer including the conductor shielding layer 5, the insulation layer and the insulation shielding layer wrapped outside the conductor 3 is formed by co-extrusion technology.

[0097] When manufacturing a submarine cable with a conductor 3 diameter difference less than 100 mm² by an integral method, the diameter difference of the conductor 3 is reduced to a value that can be directly produced and processed in the subsequent process by replacing single wires 301 with different diameters and adjusting the compacting coefficient, etc. during the conductor stranding link.

[0098] By adjusting the diameter difference of the conductor 3 during the conductor stranding link, when adopting the integral manufacturing method, a smooth transition between the conductors 3 can be ensured, thereby reducing the electrical loss and temperature rise at the connection part of the conductors 3 and improving the electrical conductivity and stability of the cable.

[0099] The overall manufacturing method adjusts the diameter difference of the conductor 3, enabling the conductor 3 to achieve the best match during the production process, reducing potential adaptation problems in subsequent processing, optimizing the production process, and improving production efficiency. The overall manufacturing method is applicable to the case where the diameter difference of the conductor 3 is small, making the cable manufacturing process more efficient, reducing costs, and enhancing the cost performance of the cable.

[0100] S4: When adopting the butt joint manufacturing method, first separately manufacture the first cable 1 for the submarine section and the second cable 2 for the landing section, and then connect the two conductors 3 through staggered layer welding of the conductor 3 to ensure a smooth transition at the connection part, and gradually restore the outer sheath structure layer of the cable layer by layer.

[0101] When manufacturing a submarine cable with a conductor 3 diameter difference less than 100 mm² by the butt joint method, the conductor transition area 4 uses conductors 3 with the same number of layers and different single wire 301 diameters for layered welding. The diameter difference of the single wire 301 of the conductor 3 decreases layer by layer from the outside to the inside, and the diameter difference of the single wire 301 of each layer does not exceed 10%. When adopting the butt joint method, through the layered welding process, the conductor transition area 4 of the conductor 3 is made smoother, avoiding problems such as poor electrical performance or insufficient mechanical strength caused by direct connection, and ensuring the stability and long-term reliability of the connection. In the butt joint method, using conductors 3 with different single wire 301 diameters for layered welding and ensuring that the diameter difference of the single wire 301 of each layer does not exceed 10% can meet the connection requirements of conductors 3 with different diameter differences while ensuring the stability and electrical conductivity of the cable.

[0102] When the cross-sectional area difference of the conductor 3 is greater than 100 mm² and less than or equal to 500 mm², the butt joint is carried out by using conductors 3 with different numbers of layers and the same single wire 301 diameter for layer-by-layer welding, and the first cable 1 and the second cable 2 are connected through staggered layer welding of the conductor 3.

[0103] For a cross-sectional area difference greater than 100 mm² and less than 200 mm², a structure with a difference of 1 layer is adopted, and for a cross-sectional area difference greater than 200 mm² and less than 500 mm², a structure with a difference of 2 layers is adopted; the welding angle of the conductor transition area 4 is not greater than 15°.

[0104] When the cross-sectional area difference of the conductor 3 is greater than 500 mm², conductors 3 with different numbers of layers and different single wire 301 diameters are used for layer-by-layer connection, and at least two layers of welding transition structures are used for welding. The welding angle of the conductor transition area 4 is not greater than 15°.

[0105] When the cross-sectional area difference of the conductor 3 is small, such as from 100 mm² to 200 mm², a smaller number of transition layers, i.e., 1 layer, is adopted. While when the cross-sectional area difference is large, such as from 200 mm² to 500 mm², a larger number of transition layers, i.e., 2 layers, is adopted to ensure the best connection effect in each case. For a larger difference > 500 mm², conductors 3 with different numbers of layers and different diameters of single wires 301 are used to further optimize the connection structure and ensure the stability of the connection part.

[0106] The way of welding layer by layer can reduce the electrical defects in the conductor transition area 4 through layered transition, such as current concentration or hot spot problems, improve the overall electrical conductivity and stability of the cable, and reduce the current loss and temperature rise at the joint of the conductor 3.

[0107] The angle of the welded conductor transition area 4 is not greater than 15°, which can effectively reduce the stress concentration problem at the joint, thereby reducing the fatigue damage of the cable during long-term operation and increasing the service life and reliability of the cable.

[0108] The design of different numbers of layers makes the pressure on the cable joints more evenly distributed, reduces the tensile and compressive stresses at the joints, and helps to improve the tensile strength and compressive capacity of the cable under high-load operating conditions.

[0109] By controlling the changes in the diameter of the single wires 301 and the number of layers of the conductor 3, the quality of each welded connection is ensured to be consistent, and the human error during the welding process is reduced, thereby improving the overall quality control level of the cable products.

[0110] When gradually restoring the outer structure layer of the cable, the conductor shielding layers 5, insulation layers, and insulation shielding layers of the first cable 1 and the second cable 2 of the submarine cable are connected from the inside to the outside respectively. Among them, the angle of the conductor shielding layer transition area 8 is not greater than 12°, the angle of the insulation layer transition area is not greater than 8°, and the angle of the insulation shielding layer transition area is not greater than 5°. By specifying the angle limits of the conductor shielding layer 5, insulation layer, and insulation shielding layer transition areas, a smooth transition between each layer structure is ensured. The stress concentration in the transition area is reduced, and material yield, cracking, or thermal damage caused by too large an angle is avoided, thereby improving the mechanical strength and service life of the cable.

[0111] The above-described submarine cable with unequal-diameter conductors and its manufacturing method are specific embodiments of the present invention, which have already reflected the substantial features and progress of the present invention. According to the actual usage needs, under the inspiration of the present invention, equivalent modifications can be made to its shape, structure, etc., and all are within the protection scope of this solution.

Claims

1. A submarine cable with unequal diameter conductors, characterized in that: The submarine cable comprises a first cable (1) for the mid-sea section and a second cable (2) for the landing section; the diameter of the conductor (3) of the second cable (2) is greater than the diameter of the conductor (3) of the first cable (1); the first cable (1) and the second cable (2) are connected to form a whole submarine cable by integral manufacturing or docking; The integrally manufactured submarine cable is produced by directly manufacturing and processing the conductors (3) of the first cable (1) and the second cable (2) in a subsequent process of the cable production line after the difference in diameter of the conductors (3) is reduced to a set threshold value in the conductor twisting link, and the conductor shielding layer (5), the insulating layer and the insulating shielding layer on the outer periphery of the conductor (3) are completed in the production line by a three-layer co-extrusion method; The butted submarine cables are formed by separately manufacturing a first cable (1) and a second cable (2), and connecting the conductors (3) of the first cable (1) and the second cable (2) by staggered welding of the conductors (3), and restoring the structural layers outside the cable conductors (3) at the connection point.

2. The submarine cable with unequal diameter conductors according to claim 1, characterized in that: The difference in cross-section of the conductors (3) of the first cable (1) and the second cable (2) of the integrally manufactured submarine cable is less than 100 mm²; in the conductor twisting link of the integrally manufactured submarine cable, the difference in the diameter of the conductors (3) is reduced to a value that can be directly produced and processed in the subsequent production by replacing single wires (301) of different diameters and / or adjusting the compression coefficient.

3. The submarine cable with unequal diameter conductors according to claim 1, characterized in that: In a butt-jointed submarine cable in which the cross-sectional difference between the conductors (3) of the first cable (1) and the second cable (2) is less than 100 mm², the conductor transition zone (4) uses conductors (3) with the same number of layers but different single-filament (301) diameters for layered welding, the diameter difference of the single-filament (301) of the conductor (3) decreases layer by layer from the outside to the inside, and the diameter difference of the single-filament (301) of each layer does not exceed 10%.

4. The submarine cable with unequal diameter conductors according to claim 3, characterized in that: A butt-jointed submarine cable with a conductor (3) cross-sectional difference greater than 100 mm² and less than or equal to 500 mm², wherein the conductor transition zone (4) is butt-jointed by welding conductors (3) with different numbers of layers and the same single wire (301) diameter layer by layer, and the first cable (1) and the second cable (2) are connected by staggered welding of the conductors (3); For submarine cables with a conductor (3) cross-sectional difference greater than 100 mm² and less than 200 mm², the conductor transition zone (4) adopts a structure with a difference of 1 layer. For submarine cables with a conductor (3) cross-sectional difference greater than 200 mm² and less than 500 mm², the conductor transition zone (4) adopts a structure with a difference of 2 layers. The angle of welding the conductor transition zone (4) is not greater than 15°.

5. The submarine cable with unequal diameter conductors according to claim 4, characterized in that: In a butt-jointed submarine cable with a conductor (3) cross-sectional difference greater than 500 mm², the conductor transition zone (4) is connected layer by layer using conductors (3) with different numbers of layers and different single-filament (301) diameters, and is welded using a welding transition structure of at least two layers, and the angle of the welding conductor transition zone (4) is not greater than 15°.

6. The submarine cable with unequal diameter conductors according to claim 1, characterized in that: The conductor shielding layer (5), the insulating layer and the insulating shielding layer of the first cable (1) and the second cable (2) of the submarine cable are connected from the inside to the outside, respectively, wherein the angle of the conductor shielding layer transition zone (8) is not greater than 12°, the angle of the insulating layer transition zone is not greater than 8°, and the angle of the insulating shielding layer transition zone is not greater than 5°.

7. A method for manufacturing a submarine cable with unequal diameter conductors, characterized in that The following steps are involved: 1) designing the conductor (3) diameters according to the environmental factors and load requirements of the mid-sea section and the landing section, respectively, to obtain the conductor (3) diameter of the first cable (1) for the mid-sea section and the conductor (3) diameter of the second cable (2) for the landing section; 2) determining the difference between the diameter of the conductor (3) of the first cable (1) and the diameter of the conductor (3) of the second cable (2); if the difference is less than a first set value, manufacturing the submarine cable in an integral or butt-jointed manner; if the difference is greater than the first set value, manufacturing the submarine cable in a butt-jointed manner; 3) When the integral manufacturing method is adopted, the diameter difference of the conductor (3) is adjusted during the twisting process of the conductor (3) so that the diameter difference between the two sections of the conductor (3) is less than a set threshold value, and the process is directly performed in the subsequent process of the cable production line, and the structural layers including the conductor shielding layer (5), the insulation layer and the insulation shielding layer that are wrapped around the conductor (3) are formed by co-extrusion technology; 4) When the butt-jointed manufacturing method is adopted, the first cable (1) for the mid-sea section and the second cable (2) for the landing section are first manufactured separately, and then the two sections of the conductor (3) are connected by staggered welding of the conductor (3) to ensure a smooth transition at the connection part, and the outer sheath structure layer of the cable is restored layer by layer.

8. The method for manufacturing a submarine cable with unequal diameter conductors according to claim 7, characterized in that: The first set value is 100 mm²; when a submarine cable with a conductor (3) diameter difference of less than 100 mm² is manufactured in an integral manner, the conductor (3) diameter difference is reduced to a value that can be directly produced and processed in the subsequent conductor twisting process by replacing single wires (301) with different diameters and / or adjusting the compression coefficient; When a submarine cable with a conductor (3) diameter difference of less than 100 mm² is manufactured by butt-jointing, conductors (3) with the same number of layers but different single wire (301) diameters are welded in layers in the conductor transition zone (4), and the diameter difference of the single wire (301) of the conductor (3) decreases layer by layer from the outside to the inside, and the diameter difference of the single wire (301) of each layer does not exceed 10%.

9. The method for manufacturing a submarine cable with unequal diameter conductors according to claim 7, characterized in that: When the difference in cross-section of the conductors (3) is greater than 100 mm² and less than or equal to 500 mm², conductors (3) with different numbers of layers and the same single wire (301) diameter are butt-jointed by welding layer by layer, and the first cable (1) and the second cable (2) are connected by staggered welding of the conductors (3); When the cross-sectional difference is greater than 100 mm² and less than 200 mm², a structure with a difference of one layer is adopted; when the cross-sectional difference is greater than 200 mm² and less than 500 mm², a structure with a difference of two layers is adopted; the angle of the welding conductor transition zone (4) is not greater than 15°; When the difference in cross-section of the conductor (3) is greater than 500 mm², conductors (3) with different numbers of layers and different single wire (301) diameters are used for layer-by-layer connection, and at least two layers of welding transition structures are used for welding, and the angle of the welding conductor transition zone (4) is not greater than 15°.

10. The method for manufacturing a submarine cable with unequal diameter conductors according to claim 7, characterized in that: The conductor shielding layer (5), the insulating layer and the insulating shielding layer of the first cable (1) and the second cable (2) of the submarine cable are connected from the inside to the outside, respectively, wherein the angle of the conductor shielding layer transition zone (8) is not greater than 12°, the angle of the insulating layer transition zone is not greater than 8°, and the angle of the insulating shielding layer transition zone is not greater than 5°.

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