OPGW optical cable and preparation method thereof

Abstract

The invention provides an OPGW optical cable and a preparation method thereof, the OPGW optical cable comprises an optical unit and an aluminum coating layer coating the surface of the optical unit, the optical unit comprises a stainless steel tube and at least one optical fiber located in the stainless steel tube, the aluminum coating layer coats the surface of the stainless steel tube, the thickness of the aluminum coating layer is 1.30-1.40 mm, and the thickness of the stainless steel tube is 0.20-0.30 mm. According to the OPGW optical cable, the thin-wall stainless steel tube and the thick-wall aluminum coating layer are combined, the mechanical performance of the optical cable is improved, the outer diameter of the optical unit is reduced, the overall weight of the optical cable is reduced, and compatibility of mechanical strength, light weight and construction adaptability is achieved.

Description

Technical Field

[0001] This application relates to the field of OPGW optical cable technology, and in particular to an OPGW optical cable and its manufacturing method. Background Technology

[0002] Fiber-optic composite overhead ground wire (OPGW), as a core component of modern power systems, simultaneously serves the dual functions of lightning protection grounding for transmission lines and fiber optic communication, playing an irreplaceable role in smart grid construction. With the rapid development of ultra-high voltage power grid construction and new energy grid integration, the number of fiber cores that OPGW needs to carry is constantly increasing, placing higher demands on mechanical reliability and signal transmission stability, especially on the lateral pressure resistance of the optical cable.

[0003] In complex field construction environments, traditional PBT core structure OPGW optical cables frequently exhibit insufficient resistance to mechanical damage. Engineering practice shows that during tension erection, factors such as mismatched pulley sizes, excessive tension (exceeding 40% of the rated breaking force), or lateral compression can cause irreversible plastic deformation of the optical units, resulting in additional attenuation due to fiber stress. Furthermore, with the popularization of power Internet of Things and big data technologies, the demand for high-core-count OPGW (48 cores or more) cables is rapidly increasing, while the mechanical performance of traditional optical cables deteriorates further when accommodating more optical fibers, particularly the lateral pressure resistance of the optical units. Summary of the Invention

[0004] In view of this, in order to solve at least one of the above defects, it is necessary to provide an OPGW optical cable with high resistance to lateral pressure and a method for manufacturing the same. The OPGW optical cable has high resistance to lateral pressure and can effectively reduce the weight of the optical cable, reduce the outer diameter of the optical cable, and improve space utilization.

[0005] In a first aspect, embodiments of this application provide an OPGW optical cable, including an optical unit and an aluminum cladding layer covering the surface of the optical unit. The optical unit includes a stainless steel tube and at least one optical fiber located inside the stainless steel tube. The aluminum cladding layer covers the surface of the stainless steel tube, and the thickness of the aluminum cladding layer is 1.30~1.40mm. The thickness of the stainless steel tube is 0.20~0.30mm.

[0006] In some possible embodiments, the stainless steel tube has a recessed texture structure on the surface facing the aluminum cladding layer. The groove depth of the recessed texture structure ranges from 0.03 mm to 0.07 mm, the width-to-depth ratio of the texture is 2.5:1, and the coverage is 60% to 80%.

[0007] In some possible embodiments, the OPGW optical cable further includes an aluminum-clad steel stranded layer disposed on the surface of the aluminum cladding layer.

[0008] Secondly, this application provides a method for manufacturing an OPGW optical cable, comprising the following steps: forming an aluminum cladding layer on the surface of an optical unit by an extrusion cladding process, wherein the optical unit includes a stainless steel tube and at least one optical fiber located inside the stainless steel tube, and the aluminum cladding layer covers the surface of the stainless steel tube; and cooling the aluminum cladding layer by a gradient cooling process to obtain the OPGW optical cable, wherein in the OPGW optical cable, the thickness of the aluminum cladding layer is 1.30~1.40mm, and the thickness of the stainless steel tube is 0.20~0.30mm.

[0009] In some possible embodiments, the gradient cooling includes a first cooling stage and a second cooling stage. The first cooling stage uses a high-pressure fan for air cooling, with the air speed controlled at 20~40m / s, to cool the temperature to 280~320℃. The second cooling stage uses water cooling, with the water pressure controlled at 0.4~0.6MPa, to cool the temperature to room temperature.

[0010] In some possible embodiments, the cooling rate of the first cooling stage is 50~60℃ / min, and the cooling rate of the second cooling stage is 10~15℃ / min.

[0011] In some possible embodiments, the heating temperature in the extrusion coating process is 450~550℃, the extrusion pressure is 500~550MPa, and the pre-heating time of the extrusion coating equipment is 30±5min.

[0012] In some possible embodiments, the thickness of the aluminum cladding layer and the extrusion pressure are related as follows: in the OPGW optical cable, for every 1 mm increase in the thickness of the aluminum cladding layer, the extrusion pressure increases by 15% to 18%.

[0013] In some possible embodiments, the extrusion ratio of the extrusion coating process is 18:1 to 20:1.

[0014] In some possible embodiments, the extrusion speed in the extrusion coating process is 0.5~0.7m / min.

[0015] In some possible embodiments, the surface of the stainless steel tube facing the aluminum cladding layer is provided with a recessed texture structure, the recessed texture structure having a coverage of 60% to 80%.

[0016] The lateral pressure resistant OPGW optical cable and its manufacturing method provided in this application, through extrusion cladding and gradient cooling processes, can uniformly coat the surface of a thin-walled stainless steel tube with a thick-walled aluminum cladding layer. By optimizing the matching of material type and wall thickness, the outer diameter of the optical unit is effectively reduced while ensuring that the basic performance such as rated tensile strength and short-circuit current capacity are not affected. At the same time, the overall weight of the optical cable is reduced, and the mechanical strength of the optical cable is improved, especially the lateral pressure resistance is significantly improved, achieving the effect of "reducing weight without reducing strength". Moreover, the use of a thin-walled stainless steel tube combined with a thick-walled aluminum cladding layer can also improve the temperature resistance of the optical cable, thereby achieving compatibility of mechanical strength, lightweight and construction adaptability. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of an OPGW optical cable provided in an embodiment of this application.

[0018] Figure 2 This is a flowchart illustrating the fabrication process of an OPGW optical cable according to an embodiment of this application.

[0019] Figure 3 This is a schematic diagram of the structure of an optical unit provided in an embodiment of this application.

[0020] Figure 4 In order to be in Figure 3 A schematic diagram of the structure of the optical unit surface covered with an aluminum cladding layer.

[0021] Figure 5 The diagram below is a structural schematic of the OPGW optical cable provided in Comparative Example 1 or Comparative Example 2 of this application.

[0022] Explanation of key component symbols: 100, optical unit; 110, optical fiber; 120, fiber optic paste; 130, stainless steel tube; 200, aluminum cladding layer; 300, stranded wire layer; 10, cladding busbar; 1, OPGW optical cable.

[0023] The following detailed description, in conjunction with the accompanying drawings, will further illustrate this application. Detailed Implementation

[0024] The following description will refer to the accompanying drawings to provide a more complete picture of the present application. The drawings illustrate exemplary embodiments of the present application. However, the present application may be implemented in many different forms and should not be construed as limited to the exemplary embodiments set forth herein. These exemplary embodiments are provided to make the present application thorough and complete, and to fully convey the scope of the present application to those skilled in the art. The same reference numerals denote the same or similar components.

[0025] The terminology used herein is for the purpose of describing particular exemplary embodiments only and is not intended to limit the application. As used herein, unless the context clearly indicates otherwise, the singular forms “a,” “an,” and “the” are intended to also include the plural forms. Furthermore, when used herein, “comprising” and / or “including” and / or “having,” integers, steps, operations, components, and / or components, but does not exclude the presence or addition of one or more other features, regions, integers, steps, operations, components, and / or groups thereof.

[0026] Unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains. Furthermore, unless expressly defined herein, terms such as those defined in a general dictionary should be interpreted as having the same meaning as they have in the relevant art and in the content of this application, and will not be interpreted as having an idealized or overly formal meaning.

[0027] The specific embodiments of this application will be further described in detail below with reference to the accompanying drawings.

[0028] Please see Figure 1 As shown in the figure, this application provides an OPGW optical cable 1 with lateral pressure resistance. The OPGW optical cable 1 includes an optical unit 100, an aluminum cladding layer 200, and a stranded layer 300 arranged sequentially from the inside to the outside. The optical unit 100 includes a stainless steel tube 130, at least one optical fiber 110 located inside the stainless steel tube 130, and fiber grease 120 filling the gap. In the OPGW optical cable 1, the thickness of the aluminum cladding layer 200 is greater than the thickness of the stainless steel tube 130, thus forming a composite reinforcement structure of "thin stainless steel tube optical unit + thickened aluminum cladding layer". Under the premise of ensuring that the basic performance such as rated breaking strength (RTS) and short-circuit current capacity remain unchanged, a breakthrough improvement in lateral pressure resistance is achieved. At the same time, the weight is reduced and the outer diameter is reduced, solving the contradiction between mechanical strength, lightweight and construction adaptability that cannot be achieved by traditional solutions.

[0029] In some embodiments, the thickness of the aluminum cladding layer 200 can be 1.30~1.40 mm. For example, the thickness of the aluminum cladding layer 200 can be 1.30 mm, 1.31 mm, 1.32 mm, 1.33 mm, 1.34 mm, 1.35 mm, 1.36 mm, 1.37 mm, 1.38 mm, 1.39 mm, 1.40 mm, or any two of the above values.

[0030] In some embodiments, the thickness of the stainless steel tube 130 in the optical unit 100 can be 0.20~0.30mm. For example, the thickness of the stainless steel tube 130 can be 0.20mm, 0.21mm, 0.22mm, 0.23mm, 0.24mm, 0.25mm, 0.26mm, 0.27mm, 0.28mm, 0.29mm, 0.30mm or any two of the above values.

[0031] Preferably, the thickness of the aluminum cladding layer 200 can be 1.35±0.02mm, and the thickness of the stainless steel tube 130 can be 0.25±0.02mm. The composite reinforcement structure of "thin stainless steel tube optical unit + thickened aluminum cladding layer" formed by the stainless steel tube 130 and the aluminum cladding layer 200 within this range can maximize the compatibility of the optical cable's lateral pressure resistance, lightweight design, and space utilization.

[0032] More preferably, the thickness of the aluminum cladding layer 200 can be 1.35 mm, and the thickness of the stainless steel tube 130 can be 0.25 mm.

[0033] In some embodiments, a thin-walled stainless steel tube 130 is used, and the outer diameter of the optical unit 100 can be 4.8 mm. Compared with the traditional PBT cable core, the stainless steel tube 130 can accommodate more optical fibers with the same outer diameter of the optical unit, which effectively improves the space utilization rate.

[0034] The core breakthrough of this application lies in solving the industry challenge of "the incompatibility between compressive strength and lightweight": through the synergistic reinforcement mechanism of a thin-walled stainless steel tube 130 and a thickened aluminum cladding layer 200, the stainless steel tube 130 provides inner rigid support, while the thickened aluminum cladding layer 200 resists external pressure. Compared with optical cables with traditional PBT core structures, this combination improves lateral pressure resistance by more than 80% while reducing the outer diameter by 5% to 10% and the weight by more than 4%. Engineering verification shows that this structure reduces the construction failure rate by more than 90%, making it particularly suitable for high-end scenarios such as ultra-high voltage lines with complex terrain and large-core IoT networks, providing high-reliability communication guarantees for smart grid construction.

[0035] Please see Figure 2 As shown, please refer to the following: Figure 1 , Figure 3 and Figure 4 As shown, this embodiment provides a method for preparing the aforementioned lateral pressure resistant OPGW optical cable 1, specifically including the following steps: Step S1, as follows Figure 3 As shown, an optical unit 100 is provided.

[0036] Among them, the optical unit 100 is used to transmit optical signals, such as Figure 3As shown, the optical unit 100 includes a stainless steel tube 130 and one or more optical fibers 110 located within the stainless steel tube 130. The stainless steel tube 130 can be formed seamlessly by a laser welding process, improving sealing performance.

[0037] In some embodiments, the thickness of the stainless steel tube 130 in the OPGW optical cable 1 product can be 0.20~0.30mm, for example, 0.2mm, 0.25mm, 0.3mm, etc. Using a thin-walled stainless steel tube 130 to directly accommodate the optical fiber 110 provides flexibility while improving the thermal stability and lateral pressure resistance of the optical unit 100. Compared to traditional PBT plastic tubes, the crush resistance of the stainless steel tube 130 is increased by 70% (from 2.5kN / 10cm to ≥8.0kN / 10cm), and the temperature resistance jumps to 450℃, effectively resisting short-circuit current surges. Moreover, using only one thin-walled stainless steel tube 130 can reduce the outer diameter of the OPGW optical cable 1, thus reducing its weight.

[0038] In some embodiments, in the OPGW optical cable 1 product, the outer diameter of the optical unit 100 can be 4.8 mm. Compared with the traditional PBT tube optical unit (typically with an outer diameter of 7.7 mm), under the premise of accommodating the same number of optical fibers, using a thin-walled stainless steel tube 130 to accommodate the optical fiber 110 can effectively reduce the outer diameter of the optical unit 100, reserve space for the optimization of the outer structure, and improve space utilization.

[0039] In some embodiments, the stainless steel tube 130 can be made of 304 or 316L, balancing cost and protection requirements.

[0040] In some embodiments, the optical fiber 110 has certain gaps within the stainless steel tube 130, and these gaps can be filled with fiber grease 120. The fiber grease 120 can be a high-temperature resistant fiber grease or aramid yarn, etc., which can play a role in protecting the optical fiber connection, reducing reflection loss, compensating for optical fiber misalignment, protecting the fiber core surface, providing a stable environment, and being waterproof and moisture-proof, thereby improving the service life of the optical fiber.

[0041] Step S2, as follows Figure 4 As shown, an aluminum cladding layer 200 is formed on the surface of the optical unit 100 through an extrusion coating process. The aluminum cladding layer 200 covers the surface of the stainless steel tube 130.

[0042] A continuous extrusion coating process is used to continuously deform aluminum material (such as aluminum rods or ingots) through a die and directly coat it onto the outer surface of the traveling optical unit 100, forming a seamless aluminum coating layer 200. The seamless coating process can improve the sealing performance of the aluminum coating layer 200 and the bonding strength with the stainless steel tube 130.

[0043] In some embodiments, the heating temperature in the extrusion coating process can be 450~550℃. Within this temperature range, the aluminum material can be guaranteed to have good fluidity and plasticity, thereby achieving a better seamless extrusion coating effect and avoiding excessive or uneven internal pressure caused by the hardness of the aluminum material, which could lead to local mechanical damage to the internal light unit 100.

[0044] In some embodiments, during the extrusion coating process, the pre-heating time of the extrusion coating equipment can be 30 ± 5 minutes. For example, when producing a 1.35 mm aluminum cladding layer, the equipment heat preservation time can be around 30 minutes, which is about 40% longer than the equipment heat preservation time for a 1.0 mm aluminum cladding layer. During the extrusion coating process, the equipment heat preservation time is adjusted according to the thickness of the aluminum cladding layer 200 to improve coating uniformity, thereby improving the thickness uniformity of the aluminum cladding layer 200.

[0045] In some embodiments, the extrusion pressure in the extrusion coating process can be 500~550MPa. By controlling the extrusion pressure within the above range, the thickness uniformity of the aluminum cladding layer 200 can be improved, while the risk of the aluminum cladding layer 200 cracking can be reduced.

[0046] The thickness of the aluminum cladding layer 200 and the extrusion pressure are related as follows: In the OPGW optical cable 1, for every 1mm increase in the thickness of the aluminum cladding layer 200, the extrusion pressure increases by 15%~18%. The extrusion pressure can be designed according to the required thickness of the aluminum cladding layer 200 in the product, which can effectively prevent the aluminum cladding layer 200 from cracking during the extrusion process.

[0047] In some embodiments, the extrusion ratio of the extrusion coating process can be 18:1 to 20:1, wherein the ratio of the cross-sectional area of ​​the aluminum material before extrusion to the effective cross-sectional area of ​​the annular layer 200 formed outside the optical unit 100 after extrusion follows the law of constant volume. This ratio reflects the degree of deformation of the aluminum material and determines the density, strength, and surface quality of the aluminum cladding layer 200. If the extrusion ratio is too small, the aluminum material will not deform sufficiently, and defects such as poor bonding, pinholes, and loose sheathing are likely to occur, failing to meet the mechanical strength and lightning protection requirements of the OPGW optical cable 1. If the extrusion ratio is too large, the deformation resistance will increase, and the extrusion pressure will increase sharply, easily leading to die wear, cracking of the aluminum cladding layer 200, and even damage to the optical unit 100. By controlling the extrusion ratio within the above range, the bonding force between the aluminum cladding layer 200 and the optical unit 100, the density of the aluminum cladding layer 200, its strength, and surface quality can be effectively improved, which is beneficial to improving the lateral pressure resistance of the final formed OPGW optical cable 1.

[0048] Preferably, when the required aluminum cladding thickness for the OPGW optical cable 1 is 1.35 mm, the extrusion ratio can be 18:1. Controlling the extrusion ratio within this preferred range means that the process parameters (temperature, speed, extrusion pressure) are within a stable and controllable "window." This helps ensure consistent product quality, reduce scrap rates, extend mold life, and achieve stable mass production. When the OPGW optical cable 1 is subjected to tower mounting point pressure, ice load, or external impact, the aluminum tube formed by the high extrusion ratio can effectively resist deformation and protect the internal optical fibers.

[0049] In some embodiments, the extrusion speed in the extrusion coating process is 0.5~0.7 m / min. For example, the extrusion speed can be 0.5 m / min, 0.6 m / min, 0.7 m / min, or any two of these values. The extrusion speed affects the forming quality of the aluminum cladding layer 200, the bonding strength with the stainless steel tube 130, and the production efficiency. The extrusion speed can also be adjusted according to the thickness of the aluminum cladding layer. The thicker the layer, the lower the extrusion rate. For example, the extrusion speed for producing a 1.35 mm aluminum cladding layer is about 60% lower than that for a 1 mm aluminum cladding layer. By controlling the extrusion speed within the above range, on the one hand, the aluminum cladding layer 200 can have a smooth surface, uniform wall thickness, no obvious defects, and high strength, and can prevent the aluminum tube from breaking due to high-speed flow, while ensuring that the internal optical unit 100 is not damaged; on the other hand, it can also form a tight fit between the aluminum cladding layer 200 and the stainless steel tube 130, improving the bonding strength.

[0050] In addition, the extrusion speed needs to be reasonably designed to match the extrusion temperature and extrusion ratio. By limiting the extrusion speed, extrusion temperature and extrusion ratio within the above range, the aluminum cladding layer 200 can have a smooth surface, uniform wall thickness, no obvious defects, and a strong bond with the stainless steel tube 130, which is beneficial to improving the overall lateral pressure resistance of the OPGW optical cable 1.

[0051] Step S3, as follows Figure 3 As shown, the aluminum cladding layer 200 is cooled by a gradient cooling process to form the cladding busbar 10.

[0052] The gradient cooling process includes a first cooling stage and a second cooling stage, which are performed continuously. The first cooling stage uses a high-pressure fan for air cooling, controlling the airflow speed at 20-40 m / s, to rapidly cool the temperature to 280-320°C, with a cooling rate of 50-60°C / min. For example, the airflow speed is controlled at 30 m / s, rapidly cooling the temperature to approximately 300°C.

[0053] The second cooling stage uses water cooling, with the water pressure controlled at 0.4~0.6MPa. For example, the water pressure can be controlled at 0.5 MPa to cool down to room temperature, with a cooling rate of 10~15℃ / min.

[0054] Gradient cooling, first rapidly air-cooled to around 300℃ and then slowly water-cooled to room temperature, combines the advantages of both air and water cooling. On one hand, it rapidly passes through the sensitive precipitation zone of the aluminum alloy strengthening phase, enabling grains to grow to a suitable size, improving the strength, hardness, and fatigue resistance of the aluminum cladding layer 200, while also providing appropriate ductility, making the aluminum cladding layer 200 less prone to cracking. On the other hand, slow water cooling allows the aluminum cladding layer 200 to cool down gradually, minimizing the temperature difference between the inner and outer layers of the aluminum cladding layer 200 tube and between the aluminum layer and the stainless steel optical unit. This allows the thermal stress generated in the first stage to be fully released, thereby ensuring the straightness of the aluminum cladding layer 200 and preventing defects such as cracking, warping, and debonding at the bonding interface.

[0055] Additionally, a recessed texture structure (not shown in the figure) can be designed on the surface of the stainless steel tube 130. This recessed texture structure can include numerous pits and bumps, creating a rough surface texture that improves wettability and forms a serrated interface structure. When the aluminum cladding layer 200 is applied to the stainless steel tube 130, the interfacial bonding force is enhanced through a mechanical interlocking effect. For example, when the recessed texture structure depth is 0.03mm-0.07mm and the width-to-depth ratio is 2.5:1, the interfacial bonding strength can reach 80-90MPa, meeting the requirements of projects in harsh environments.

[0056] In addition, the coverage of the recessed texture structure can be controlled to be 60%~80% to further improve the interfacial bonding force. For example, when the coverage reaches 70%, the recessed texture structure can increase the shear strength to 100MPa.

[0057] Step S4: Perform multiple synchronous stretching operations on the covered busbar 10.

[0058] The main purpose of the stretching here is to straighten the bent busbar 10, so that the thickness of the aluminum cladding layer 200 is 1.30~1.40mm, that is, the thickness of the aluminum cladding layer 200 in the OPGW optical cable 1 is 1.30~1.40mm. For example, the aluminum cladding layer 200 can be 1.35mm.

[0059] Step S5, as follows Figure 4 As shown, a stranded layer 300 can also be formed on the surface of the aluminum cladding layer 200 to obtain the OPGW optical cable 1. Specifically, the stranded layer 300 can be an aluminum-clad steel stranded layer.

[0060] The thickened aluminum cladding layer 200 provides sufficient rigid support, significantly improves the stress concentration problem of the stranded layer 300 on the optical unit 100, reduces the ellipticity of the optical unit 100 under the rated breaking force (RTS), and improves the pulley performance.

[0061] In this embodiment, the thickness of the aluminum cladding layer 200 in the formed OPGW optical cable 1 can be increased to a thick-walled cladding layer of 1.30~1.40mm (e.g., 1.35mm). Due to the low density of aluminum, the overall weight of the optical cable can be effectively reduced even with a moderate increase in the thickness of the aluminum cladding layer 200 through density difference compensation. Simultaneously, the combination of the single-layer thin-walled stainless steel tube 130 and the thick-walled aluminum cladding layer 200 can effectively reduce the outer diameter of the OPGW optical cable 1 by 5%~10%, reserving space for optimization of the outer structure. This allows for the use of smaller diameter pulleys, significantly improving the construction adaptability in restricted areas such as mountainous regions and urban networks. Furthermore, in the optical unit 100, the use of a stainless steel tube 130 instead of a traditional plastic tube, combined with the thick-walled aluminum cladding layer 200, effectively improves the mechanical properties of the OPGW optical cable 1, especially significantly improving its resistance to lateral pressure and temperature resistance, thus resisting short-circuit current surges.

[0062] The lateral pressure resistant OPGW optical cable 1 and its preparation method provided in this application, through extrusion coating process and gradient cooling process, can coat the surface of thin-walled stainless steel tube 130 with a uniform thick-walled aluminum cladding layer 200. Through optimized matching of material type and wall thickness, while ensuring that the basic performance such as rated tensile force and short-circuit current capacity are not affected, the outer diameter of the optical unit 100 is effectively reduced, the overall weight of OPGW optical cable 1 is reduced, and the mechanical strength of OPGW optical cable 1 is improved. In particular, the lateral pressure resistance is significantly improved, achieving the effect of "reducing weight without reducing strength".

[0063] A synergistic reinforcement mechanism combining a thin-walled stainless steel tube 130 and a thick-walled aluminum cladding layer 200 is employed. Through this mechanism, the stainless steel tube 130 provides inner rigid support, while the thickened aluminum cladding layer 200 resists external stress. This combination increases lateral pressure resistance by over 80%, while simultaneously reducing the outer diameter of the optical unit 100 by 5%-10% and the cable weight by over 4%. Engineering verification shows that this structure reduces construction failure rates by 90%, making it particularly suitable for high-end scenarios such as UHV lines in complex terrain and large-core IoT networks, providing high-reliability communication guarantees for smart grid construction. Furthermore, the synergistic reinforcement mechanism of the thin-walled stainless steel tube 130 and the thick-walled aluminum cladding layer 200 also improves the temperature resistance of the OPGW optical cable 1, thus achieving a balance between mechanical strength, lightweight design, and construction adaptability, solving the industry challenge of "the incompatibility of compressive strength and lightweight design."

[0064] The OPGW optical cable 1 provided in this application embodiment has enhanced lateral pressure resistance and is suitable for harsh environments requiring resistance to mechanical external forces (such as compression, impact, wind vibration, etc.). Its main application areas include: high wind speed or strong typhoon areas, reducing cable swaying and compression caused by wind vibration, and preventing damage to optical fibers due to long-term mechanical stress; areas with severe icing, preventing damage to the optical cable structure from instantaneous lateral pressure generated during ice accumulation or de-icing, ensuring communication stability; long-span transmission lines, where the long span increases cable weight and wind load, and the lateral pressure-resistant structure can withstand additional lateral stress; and narrow spaces such as urban power grids and industrial areas, resisting accidental lateral pressure from construction misoperations, vehicle collisions, etc. For example, this OPGW optical cable 1 can be used for the expansion and renovation of old lines, greatly increasing the lateral pressure resistance of the structure while maintaining basic performance such as RTS and short-circuit current, while reducing the outer diameter and weight, which is more beneficial for line design.

[0065] The present application's solution will be explained below with reference to embodiments. Those skilled in the art will understand that the following examples are for illustrative purposes only and should not be construed as limiting the scope of the application. Unless otherwise specified, the raw materials and instruments involved in the following embodiments, unless otherwise specifically mentioned, are all commercially available products or instruments commonly used in the field.

[0066] Example 1 Step 1: Provide an optical unit, in which the thickness of the stainless steel tube is 0.25mm.

[0067] Step 2: Apply an aluminum cladding layer to the surface of the optical unit through an extrusion coating process. The heating temperature is 450~550℃, the holding time is 30min, the extrusion pressure is 500~550MPa, the extrusion ratio is 18:1, and the extrusion speed is 0.5~0.7m / min.

[0068] Step 3: Gradient cooling is performed on the aluminum cladding layer to obtain the clad busbar. The first cooling stage uses a high-pressure fan for air cooling, with the air speed controlled at 30 m / s, to rapidly cool down to 300℃ at a cooling rate of 50~60℃ / min. The second cooling stage uses water cooling at a water pressure of 0.5 MPa to cool down to room temperature at a cooling rate of 10~15℃ / min.

[0069] Step 4: Straighten and stretch the covered busbar.

[0070] Step 5: Form an aluminum-clad steel stranded layer on the surface of the aluminum cladding layer to obtain a 70kN small-structure OPGW optical cable. The thickness of the aluminum cladding layer is 1.35mm. For specific parameters, please refer to Table 1 below.

[0071] Example 2 The preparation method is basically the same as that in Example 1. The difference is that the 120kN large structure was prepared in Example 2. Please refer to Table 1 below for specific parameters.

[0072] Comparative Example 1 Step 1: Prepare multiple optical fibers to be released at a uniform speed from the pay-off stand. Passing through a series of guide rollers and a tension control system, ensure that the tension of each optical fiber is minimal, uniform, and stable to prevent additional attenuation due to micro-bending.

[0073] Step 2: Add the dried PBT material to the extruder and melt and plasticize it at 240-260℃. The melt is then extruded through a precision annular die head to form a tube blank.

[0074] Step 3: The tube blank immediately undergoes cooling and sizing, biaxial stretching oven (longitudinal stretching + transverse diameter expansion), and heat setting to form a high-performance PBT loose tube. At this stage, the PBT tube is a continuously moving "semi-finished product." Multiple optical fibers from the guiding device are concentrically and loosely fed into the center of the newly formed and still moving PBT tube through a central guide pin. This "loose tube" design allows the optical fibers a certain amount of free movement within the tube, preventing external forces from directly acting on the optical fibers.

[0075] Comparative Example 2 The preparation method is basically the same as that of Comparative Example 1. The difference is that Comparative Example 2 prepared a 120kN large structure. Please refer to Table 1 below for specific parameters.

[0076] The relevant parameters of the OPGW optical cables in Examples 1-2 and Comparative Examples 1-2 are shown in Table 1.

[0077] Table 1 Please refer to the structures of the OPGW optical cables in Examples 1 and 2. Figure 4 The structure shown is different from that of the OPGW optical cables in Comparative Examples 1 and 2. Figure 5 As shown.

[0078] As shown in Table 1, the analysis and verification show that the 1.35mm aluminum-clad OPGW optical cables prepared in Examples 1 and 2 have an optical unit ellipticity of only 5.92% under 70% RTS tension (the standard requirement is ≤10% optical unit ellipticity under 15% RTS tension), and the pulley performance is improved by 57.1%.

[0079] The outer diameter of the optical unit in Examples 1 and 2 is 4.8 mm, while the outer diameter of the optical unit in Comparative Examples 1 and 2 is 7.7 mm. Compared with Comparative Examples 1 and 2, the outer diameter of the optical unit in Examples 1 and 2 is reduced by 38%, which can reserve sufficient space for the optimization of the outer structure of the optical cable.

[0080] Furthermore, the outer diameter of the aluminum-clad optical units in Examples 1 and 2 is L1, where L1 = 4.8mm + 1.35mm*2 + 0.2mm (gap) = 7.7mm; while the outer diameter of the aluminum-clad optical units in Comparative Examples 1 and 2 is L2, where L2 = 7.7mm + 1mm*2 + 0.2mm (gap) = 9.9mm. Compared to the optical cables in Comparative Examples 1 and 2, the optical cables in Examples 1 and 2 achieve a balance between compressive strength and lightweight by increasing the thickness of the aluminum cladding layer.

[0081] For 70kN small-structure OPGW optical cables, the weight of the OPGW optical cable in Comparative Example 1 is 570kg / km, while the weight of the OPGW optical cable in Example 1 is 548kg / km. Compared to Comparative Example 1, the OPGW optical cable in Example 1 is 3.86% lighter and has an outer diameter reduced by 11.8%. For 120kN large-structure OPGW optical cables, the weight of the OPGW optical cable in Comparative Example 2 is 936kg / km, while the weight of the OPGW optical cable in Example 2 is 902kg / km. Compared to Comparative Example 2, the OPGW optical cable in Example 2 is 3.63% lighter and has an outer diameter reduced by 6.5%. Therefore, the OPGW optical cables of Examples 1 and 2 allow the use of smaller diameter pulleys, significantly improving the construction adaptability in restricted areas such as mountainous regions and urban networks.

[0082] The above embodiments are only used to illustrate the technical solutions of this application and are not intended to limit it. Although this application has been described in detail with reference to the above preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions to the technical solutions of this application should not depart from the spirit and scope of the technical solutions of this application.

Claims

1. An OPGW optical cable, characterized in that, The device includes an optical unit and an aluminum cladding layer covering the surface of the optical unit. The optical unit includes a stainless steel tube and at least one optical fiber located inside the stainless steel tube. The aluminum cladding layer covers the surface of the stainless steel tube and has a thickness of 1.30~1.40mm. The stainless steel tube has a thickness of 0.20~0.30mm.

2. The OPGW optical cable as described in claim 1, characterized in that, The stainless steel tube has a recessed texture structure on the surface facing the aluminum cladding layer. The groove depth of the recessed texture structure ranges from 0.03mm to 0.07mm, the width-to-depth ratio of the texture is 2.5:1, and the coverage rate is 60% to 80%.

3. The OPGW optical cable as described in claim 1, characterized in that, It also includes an aluminum-clad steel wire stranded layer disposed on the surface of the aluminum cladding layer.

4. A method for manufacturing an OPGW optical cable, characterized in that, include: An aluminum cladding layer is formed on the surface of an optical unit by an extrusion coating process. The optical unit includes a stainless steel tube and at least one optical fiber located inside the stainless steel tube. The aluminum cladding layer covers the surface of the stainless steel tube. The aluminum cladding layer is cooled using a gradient cooling process to obtain the OPGW optical cable. In the OPGW optical cable, the thickness of the aluminum cladding layer is 1.30~1.40mm, and the thickness of the stainless steel tube is 0.20~0.30mm.

5. The method for preparing OPGW optical cable as described in claim 4, characterized in that, The gradient cooling includes a first cooling stage and a second cooling stage. The first cooling stage uses a high-pressure fan for air cooling, with the air speed controlled at 20~40m / s, to cool down to 280~320℃. The second cooling stage uses water cooling, with the water pressure controlled at 0.4~0.6MPa, to cool down to room temperature.

6. The method for preparing an OPGW optical cable as described in claim 5, characterized in that, The cooling rate in the first cooling stage is 50~60℃ / min, and the cooling rate in the second cooling stage is 10~15℃ / min.

7. The method for preparing an OPGW optical cable as described in claim 4, characterized in that, The heating temperature in the extrusion coating process is 450~550℃, the extrusion pressure is 500~550MPa, and the pre-heating time of the extrusion coating equipment is 30±5min.

8. The method for preparing an OPGW optical cable as described in claim 6, characterized in that, The thickness of the aluminum cladding layer and the extrusion pressure are related as follows: in the OPGW optical cable, for every 1 mm increase in the thickness of the aluminum cladding layer, the extrusion pressure increases by 15% to 18%.

9. The method for preparing an OPGW optical cable as described in claim 6, characterized in that, The extrusion ratio of the extrusion coating process is 18:1 to 20:

1.

10. The method for preparing an OPGW optical cable as described in claim 4, characterized in that, The extrusion speed in the extrusion coating process is 0.5~0.7m / min.

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