Optical fiber composite overhead ground wire having aluminum-clad three-tube stainless steel optical unit structure

Abstract

An optical fiber composite overhead ground wire having an aluminum-clad three-tube stainless steel optical unit structure, the optical fiber composite overhead ground wire comprising a core wire (4), an optical unit layer (2), an extruded aluminum tube (5) and outer wrapped steel wires (1, 3), which are sequentially arranged from inside to outside, wherein the core wire (4) is a central strength member (4) having a diameter of 0.3-0.5 mm; the inner diameter of the extruded aluminum tube (5) is 0.1-0.15 mm greater than the outer diameter of the optical unit layer; and the outer wrapped steel wires (1, 3) comprise LB20-2.60 aluminum-clad steel wires (1) and LB27-2.60 aluminum-clad steel wires (3), which are obtained by means of armoring, and several LB20-2.60 aluminum-clad steel wires (1) are arranged between every two LB27-2.60 aluminum-clad steel wires (3), the LB20-2.60 aluminum-clad steel wires (1) being aluminum-clad steel wires having a diameter of 2.6 mm and a conductivity of 20%, and the LB27-2.60 aluminum-clad steel wires (3) being aluminum-clad steel wires having a diameter of 2.6 mm and a conductivity of 27%.

Description

A fiber optic composite overhead ground wire with an aluminum-clad three-tube stainless steel optical unit structure Technical Field

[0001] This invention belongs to the field of overhead power transmission technology, specifically relating to an aluminum-clad three-tube stainless steel optical unit structure fiber composite overhead ground wire. Background Technology

[0002] Overhead lines mainly refer to exposed overhead lines, erected above the ground. They are power transmission lines that use insulators to fix the transmission conductors to towers erected on the ground to transmit electrical energy. They are relatively easy to install and maintain, and have lower costs. However, they are susceptible to weather and environmental factors (such as strong winds, lightning strikes, pollution, and snow), which can cause faults. Furthermore, the entire transmission corridor occupies a significant amount of land and can easily cause electromagnetic interference to the surrounding environment.

[0003] An overhead ground wire, also known as a lightning protection wire, is a conductor directly connected to the ground on high-voltage and ultra-high-voltage power lines. Due to the shielding effect of the overhead ground wire on the conductor and the coupling effect between the conductor and the overhead ground wire, the chance of lightning striking the conductor directly is reduced. When lightning strikes a tower, a portion of the lightning current can be diverted through the overhead ground wire, thereby lowering the tower top potential and improving the lightning withstand level.

[0004] An overhead ground wire is a conductor installed above power transmission lines to prevent them from being directly struck by lightning; it can also be called a lightning protection wire or ground wire. As the coverage area of ​​overhead transmission lines continues to expand, the probability of these lines being struck by lightning is also increasing. Since ancient times, lightning has been considered incompatible with electricity, and the overhead ground wire acts as a barrier between thunderclouds and transmission lines. Transmission lines traverse vast areas and are susceptible to lightning strikes during the rainy season, causing power outages and becoming one of the main causes of power system blackouts. Installing overhead ground wires on transmission lines can reduce lightning damage and improve the safety of line operation. The overhead ground wire is an important component of the high-voltage transmission line structure. High-voltage and ultra-high-voltage substations occupy large areas and require protection against direct lightning strikes over large areas; in addition to lightning rod protection, they also use overhead ground wires for protection. Overhead ground wires are installed above the conductors and equipment they protect. When a thundercloud discharges to the ground above the line, the lightning flash path can easily strike the overhead ground wire. The lightning current is then conducted to the ground through the grounding wire of the overhead ground wire or the metal tower itself, thus protecting the transmission line and ensuring its normal power supply. Simultaneously, the overhead ground wire also provides electromagnetic shielding, reducing the lightning-induced overvoltage on the transmission conductors when a thundercloud discharges to the ground near the line. The overhead ground wire must be securely connected to the tower grounding device to ensure that the lightning current can be reliably conducted to the ground after a lightning strike, preventing a sudden rise in potential at the lightning strike point and causing a backflash.

[0005] Statistical data shows that the main causes of power outages and tripping accidents in residential, industrial, and agricultural electricity use are lightning strikes, human-caused incidents, and natural disasters, with lightning accounting for over 60% of outages. Weather changes are uncontrollable, so efforts can only be made to improve the safety and disaster prevention capabilities of the power transmission system within the scope of human control. Overhead grounding wires are an important technical measure for disaster mitigation and prevention in power systems.

[0006] Practical application of overhead ground wires for power transmission lines shows that overhead ground wires can effectively prevent direct lightning strikes to transmission conductors; when lightning strikes transmission line towers, overhead ground wires can act as a shunting agent, reducing the potential at the top of the tower and preventing lightning backflash; when lightning strikes the ground near the transmission line, overhead ground wires can act as a shield, reducing induced lightning overvoltage on the transmission conductors.

[0007] With the rapid development of power systems, the demand for safety in existing power grid construction has become increasingly apparent. Currently, the commonly used structures for special optical cables in power systems are stranded, central tube, or aluminum-clad PBT and central tube optical unit structures. Regardless of the structure, when external environmental factors (temperature changes, snow, wind, vibration) change, the operation of power optical cables is susceptible to certain risks, which can easily cause communication problems.

[0008] Because overhead ground wires do not carry current, they are not required to have the same conductivity and cross-section as conductors, and are typically made of steel strand. During normal power transmission, the overhead ground wire will experience electromagnetic induction from the three-phase currents, resulting in current flowing through it. This increases power loss and affects transmission performance. Some transmission lines also use high-conductivity ground wires, i.e., overhead ground wires made of aluminum alloy or aluminum-clad steel conductors. These ground wires have better conductivity, improving transmission performance and reducing interference to nearby communication lines.

[0009] With the rapid development of the power industry and the improvement of the modernization level of power system management, the forms and volumes of information that need to be transmitted within the power system are increasing day by day. Combining the advantages of optical fiber communication, such as large transmission capacity, high speed, suitability for long-distance transmission, and resistance to electromagnetic induction and crosstalk interference, with the high mechanical properties, high conductivity and good corrosion resistance of aluminum-clad steel wire, the optical fiber composite overhead ground wire communication system has the performance of both overhead ground wire and communication optical cable.

[0010] Fiber optic composite overhead ground wires involve placing optical fibers within the ground wires of overhead high-voltage transmission lines to form a fiber optic communication network along the transmission line. Due to the electromagnetic interference resistance and lightweight nature of optical fibers, they can be installed on top of transmission line towers without considering optimal mounting locations or electromagnetic corrosion. Therefore, they offer significant advantages such as high reliability, superior mechanical properties, and lower cost. This technology is particularly suitable and economical for laying new ground wires or replacing existing ones. Consequently, it has gained attention in the power system industry and is gradually being adopted.

[0011] Summary of the Invention

[0012] To address the above problems, this invention provides a novel fiber optic composite overhead ground wire solution. The traditional single or double optical units are designed as a three-unit stranded structure, with a reinforcing member at the center of each unit to increase its load-bearing capacity. Simultaneously, an aluminum tube is uniformly extruded onto the surface of each stranded optical unit, giving this new optical cable excellent corrosion resistance and electrical performance. When the external environment changes, the stainless steel optical units, due to their stranded structure and larger secondary excess length, exhibit strong resistance to environmental changes.

[0013] To address the aforementioned technical problems, this application provides the following technical solution:

[0014] This invention provides an aluminum-clad three-tube stainless steel optical unit structure fiber optic composite overhead ground wire, comprising a core wire, an optical unit layer, an extruded aluminum tube, and an outer steel wire arranged sequentially from the inside out; the core wire is a central reinforcing member with a diameter of 0.3-0.5mm, and the inner diameter of the extruded aluminum tube is 0.1-0.15mm wider than the outer diameter of the optical unit layer;

[0015] The outer sheathing steel wire includes armored LB20-2.60 aluminum-clad steel wire and LB27-2.60 aluminum-clad steel wire, with several LB20-2.60 aluminum-clad steel wires spaced between each pair of LB27-2.60 aluminum-clad steel wires; wherein, the LB20-2.60 aluminum-clad steel wire is an aluminum-clad steel wire with a diameter of 2.6 mm and a conductivity of 20%; the LB27-2.60 aluminum-clad steel wire is an aluminum-clad steel wire with a diameter of 2.6 mm and a conductivity of 27%.

[0016] Preferably, the strength of the central reinforcing member is not less than 1100 MPa.

[0017] Preferably, the optical unit layer is a three-tube optical unit composed of three optical units; the three-tube optical units are uniformly twisted on the outer layer of the core wire.

[0018] Furthermore, when the three-tube optical unit is stranded, a cage stranding device is used, the wire release tension is 8-12kg, the reinforcing tension is 2.8-3.2kg, a 4.5-4.7mm Haval die is used, the stranding pitch is 100-120mm, and the take-up tension is 10kg; the three-tube stranding speed is 5-6m / min.

[0019] Preferably, the optical unit consists of 8 B1 optical fibers with a tube diameter of 2 mm and an excess fiber length of 1.5-2.5‰.

[0020] Preferably, the extruded aluminum tube is uniformly extruded onto the outer surface of the optical unit; during the extrusion of the aluminum tube, the tension of the three core wires is 3-10 kg, the pressure of the covering mold cylinder is 28-32 bar, and the covering speed is 50-60 m / min.

[0021] Preferably, the wall thickness of the extruded aluminum tube is 1-1.025 mm.

[0022] Preferably, the strength of the LB20-2.60 aluminum-clad steel wire is not less than 1390 MPa, and the strength of the LB27-2.60 aluminum-clad steel wire is not less than 1160 MPa.

[0023] Preferably, the outer sheathing steel wire consists of 7 LB20-2.60 aluminum-clad steel wires and 4 LB27-2.60 aluminum-clad steel wires.

[0024] Preferably, when the outer steel wire armor is applied, a Haval mold is used, the wire tension of the aluminum-clad steel wire is 15-20 kg, and the finished product speed is 30-35 m / min.

[0025] Specifically, the aluminum-clad three-tube stainless steel optical unit structure fiber composite overhead ground wire consists of a reinforcing member with a diameter of 0.30-0.50mm (strength ≥1100MPa) as the core wire, three 2.0-8B1 optical units are uniformly twisted on the outer layer, and a layer of aluminum tube with a wall thickness of 1mm is uniformly extruded on the surface of the optical unit, and then armored with 7 LB20-2.60 monofilaments (strength ≥1390MPa) and 4 LB27-2.60 (strength ≥1160MPa) monofilaments.

[0026] The central reinforcement with three stranded optical units increases the secondary excess length of the optical fiber, improving the safety of the optical cable operation; the extruded aluminum tube effectively reduces electrochemical corrosion between different metals; and the armored aluminum-clad steel wire ensures the structural strength of the entire cable. Meanwhile, during the extrusion of the aluminum tube, the inner diameter of the aluminum tube is designed to be approximately 0.10-0.15 mm larger than the outer diameter of the stranded optical unit. This allows the optical unit to be suspended inside the aluminum tube, further enhancing its operational safety.

[0027] The traditional single or two optical units are designed into three or more tubes, with reinforcing elements inserted between the optical units and an outer extruded aluminum tube to increase the tensile strength and electrical performance of the optical cable.

[0028] The technical solution of the present invention has the following advantages compared with the prior art:

[0029] The application of this invention provides a new optical cable option for exports, and has developed a solution to increase the operational stability of optical cables in power transmission lines, which has been well received by users. Compared with traditional PBT structures, it has better tensile strength; compared with stranded or central tube structures, it has better electrical performance. Attached Figure Description

[0030] Figure 1 shows the structure of an aluminum-clad three-tube fiber optic composite overhead ground wire.

[0031] Figure 2 shows the product process flow diagram.

[0032] Explanation of reference numerals in the attached drawings: 1-LB20-2.60 aluminum-clad steel wire, 2-three-tube optical unit, 3-LB27-2.60 aluminum-clad steel wire, 4-central reinforcing member, 5-extruded aluminum tube. Detailed Implementation

[0033] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, so that those skilled in the art can better understand and implement the present invention. However, the embodiments described are not intended to limit the present invention.

[0034] Example 1

[0035] A fiber optic composite overhead ground wire with an aluminum-clad three-tube stainless steel optical unit structure includes, from the inside out, a core wire, an optical unit layer, an extruded aluminum tube 5, and an outer steel wire.

[0036] The core wire has a 0.4mm diameter central reinforcing member 4, and the strength of the central reinforcing member 4 is not less than 1100MPa.

[0037] The optical unit layer is a three-tube optical unit 2 composed of three optical units; the three-tube optical unit 2 is uniformly twisted on the outer layer of the core wire.

[0038] Each of the three optical units consists of eight B1 optical fibers with a tube diameter of 2mm and an excess fiber length of 1.5-2.5‰.

[0039] The inner diameter of the extruded aluminum tube 5 is 0.1-0.15 mm wider than the outer diameter of the optical unit layer; at the same time, the wall thickness of the extruded aluminum tube 5 is 1-1.025 mm.

[0040] The outer sheathing steel wire is obtained by armoring 7 LB20-2.60 aluminum-clad steel wires 1 and 4 LB27-2.60 aluminum-clad steel wires 3.

[0041] The LB27-2.60 aluminum-clad steel wire 3 is provided with one or two LB20-2.60 aluminum-clad steel wires 1 between each other; wherein, the LB20-2.60 aluminum-clad steel wire 1 is an aluminum-clad steel wire with a diameter of 2.6mm and a conductivity of 20%; the LB27-2.60 aluminum-clad steel wire 3 is an aluminum-clad steel wire with a diameter of 2.6mm and a conductivity of 27%.

[0042] The strength of the above-mentioned LB20-2.60 aluminum-clad steel wire 1 is not less than 1390MPa, and the strength of the LB27-2.60 aluminum-clad steel wire 3 is not less than 1160MPa.

[0043] Example 2

[0044] The fabrication process of the aluminum-clad three-tube stainless steel optical unit structure fiber optic composite overhead ground wire is shown in Figure 2. The process involves the following steps: fiber looping → coloring → adding steel tape and fiber paste to form a tube → forming the optical unit layer → adding reinforcing members and stranding → forming the cable core → adding aluminum rods for aluminum cladding extrusion → forming the aluminum-clad optical unit → aluminum-clad steel wire stranding → cable formation → testing → packaging. The specific processes are as follows:

[0045] a) During the production of the optical unit layer, the excess fiber length is controlled at 1.5-2.5‰. Nexans laser welding equipment is used, equipped with online eddy current testing to ensure that the surface welding of the optical unit is defect-free and can be transferred to the next process. At the same time, water-blocking fiber paste is filled to ensure the water-blocking performance of each optical unit.

[0046] b) When the three-tube optical unit is stranded with reinforcing members, a cage stranding device is used. The wire tension is uniformly controlled between 8-12kg, the tension of the reinforcing members is controlled at about 3kg, the Haval mold is 4.60±0.10mm, the stranding pitch is designed between 100-120mm, and the take-up tension is controlled at 10kg to ensure the stability of the stranding quality; the three-tube stranding speed is controlled at 5-6m / min.

[0047] c) During aluminum cladding extrusion, the aluminum tube wall thickness is designed to be 1.000-1.025mm, while ensuring that the inner diameter of the aluminum tube is approximately 0.10-0.15mm larger than the outer diameter of the stranded optical unit. The tension of the three-core wire feeding is controlled between 3-10kg to avoid secondary stress on the optical unit and reduce additional attenuation. The pressure of the cladding die cylinder is controlled at around 30bar, and the cladding speed is controlled at 50-60m / min.

[0048] d) For the outer armor, a hybrid structure of LB20-2.6 and LB27-2.60 materials is adopted, with the strength of LB20-2.60 and LB27-2.60 materials both increased by 50 MPa. This ensures both the mechanical and electrical properties of the cable. The cable-forming mold uses a Haver mold that is 0.10 mm larger than that of the aluminum-clad optical unit, and the tension of the aluminum-clad steel wire is uniformly controlled between 15-20 kg, reducing secondary extrusion during stranding and ensuring the stability of cable attenuation. The finished product speed is controlled at 30-35 m / min.

[0049] During operation, this new type of fiber optic composite overhead ground wire features three-tube optical units twisted together, increasing the secondary excess length of the optical cable. At the same time, when aluminum-clad, the design gap is 0.10-0.15mm, reducing the risk of the cable being squeezed and stretched under stress, and reducing the additional loss of the optical cable.

[0050] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. An aluminum-clad triplexed stainless steel optical unit structure optical fiber composite overhead ground wire, characterized by, It includes a core wire, an optical unit layer, an extruded aluminum tube (5), and an outer steel wire arranged sequentially from the inside to the outside; the core wire is a central reinforcing member (4) with a diameter of 0.3-0.5mm, and the inner diameter of the extruded aluminum tube (5) is 0.1-0.15mm wider than the outer diameter of the optical unit layer; The outer sheathing steel wire includes armored LB20-2.60 aluminum-clad steel wire (1) and LB27-2.60 aluminum-clad steel wire (3), with several LB20-2.60 aluminum-clad steel wires (1) arranged between each pair of LB27-2.60 aluminum-clad steel wires (3); wherein, the LB20-2.60 aluminum-clad steel wire (1) is an aluminum-clad steel wire with a diameter of 2.6 mm and a conductivity of 20%; the LB27-2.60 aluminum-clad steel wire (3) is an aluminum-clad steel wire with a diameter of 2.6 mm and a conductivity of 27%.

2. The aluminum clad tri-tube stainless steel optical unit structure optical fiber composite overhead ground wire of claim 1 wherein, The strength of the central reinforcing member (4) is not less than 1100 MPa.

3. The aluminum-clad three-tube stainless steel optical unit structure fiber optic composite overhead ground wire as described in claim 1, characterized in that, The optical unit layer is a three-tube optical unit (2) composed of three optical units; the three-tube optical unit (2) is uniformly twisted on the outer layer of the core wire.

4. The aluminum-clad three-tube stainless steel optical unit structure fiber optic composite overhead ground wire as described in claim 3, characterized in that, When the three-tube optical unit (2) is twisted, a cage twisting device is used, the wire tension is 8-12kg, the tension of the reinforcing member is 2.8-3.2kg, a 4.5-4.7mm Haval die is used, the twisting pitch is 100-120mm, the wire take-up tension is 10kg, and the three-tube twisting speed is 5-6m / min.

5. The aluminum-clad three-tube stainless steel optical unit structure fiber optic composite overhead ground wire as described in claim 3, characterized in that, The optical unit consists of 8 B1 optical fibers with a tube diameter of 2 mm and an excess fiber length of 1.5-2.5‰.

6. The aluminum-clad three-tube stainless steel optical unit structure fiber optic composite overhead ground wire as described in claim 1, characterized in that, The extruded aluminum tube (5) is uniformly extruded onto the outer surface of the optical unit; when the extruded aluminum tube (5) is extruded, the tension of the three core wires is 3-10 kg, the pressure of the covering mold cylinder is 28-32 bar, and the covering speed is 50-60 m / min.

7. The aluminum-clad three-tube stainless steel optical unit structure fiber optic composite overhead ground wire as described in claim 1, characterized in that, The wall thickness of the extruded aluminum tube (5) is 1-1.025 mm.

8. The aluminum-clad three-tube stainless steel optical unit structure fiber optic composite overhead ground wire as described in claim 1, characterized in that, The strength of the LB20-2.60 aluminum-clad steel wire (1) is not less than 1390 MPa, and the strength of the LB27-2.60 aluminum-clad steel wire (3) is not less than 1160 MPa.

9. The aluminum-clad three-tube stainless steel optical unit structure fiber optic composite overhead ground wire as described in claim 1, characterized in that, The outer sheathing steel wire consists of 7 LB20-2.60 aluminum-clad steel wires (1) and 4 LB27-2.60 aluminum-clad steel wires (3).

10. The aluminum-clad three-tube stainless steel optical unit structure fiber optic composite overhead ground wire as described in claim 1, characterized in that, When the outer steel wire armor is applied, a Haval mold is used, the wire tension of the aluminum-clad steel wire is 15-20 kg, and the finished product speed is 30-35 m / min.

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