KR20210114348A - Central tension member for an overhead cable and the overhead cable comprising the same - Google Patents

Abstract

The present invention relates to a central tension line for an overhead power transmission line and an overhead power transmission line including the same and, more specifically, to a central tension line for an overhead power transmission line and an overhead power transmission line including the same which have excellent sag features, which prevent an installed overhead power transmission line from sagging downward by excellent tensile strength of the central tension line, and sufficient flexibility of the central tension line so as to increase wiring workability and suppress corrosion and damage to a conductor wire disposed around a circumference of the central tension line, thereby avoiding or minimizing a resistance increase of the overhead power transmission line and reduction in a power transmission amount accordingly.

Description

Central tension member for an overhead cable and the overhead cable comprising the same

The present invention relates to a central tension wire for an overhead power transmission line and an overhead power transmission line including the same. Specifically, the present invention has excellent tensile strength of the central tension line, so that it not only has excellent sag characteristics to prevent the overhead power transmission line from sagging downward, but also has sufficient flexibility of the central tension line to improve the workability of the wire and at the same time improve the workability of the central tension line. For overhead transmission lines that can suppress corrosion and damage of conductor wires disposed around tension lines, thereby avoiding or minimizing the increase in resistance of overhead transmission lines and consequent reduction in power transmission amount, and making it possible to lighten overhead transmission lines and reduce manufacturing costs It relates to a central tension line and an overhead power transmission line including the same.

Methods of supplying electricity from power plants to cities or factories through substations include an overhead transmission method using an overhead transmission line connected to a pylon and an underground transmission method using an underground transmission line buried underground. occupies

A conventional overhead power transmission line is generally used as an aluminum conductor steel reinforced (ACSR) overhead power transmission line in which several aluminum alloy conductors are stranded on the outer periphery of a central tension line for realizing high tension characteristics.

However, the steel core aluminum stranded wire (ACSR) overhead power transmission line has a large sag because the load of the steel core itself used as the central tension line is large, and there is a limit to increasing the weight of the aluminum conductor to increase the transmission amount of the overhead transmission line. Attempts have been made to lighten overhead power lines by using fiber-reinforced composite materials for the central tension line in order to reduce the length of the transmission line or to increase the amount of transmission compared to the same length.

1 schematically shows a cross-sectional structure of a conventional overhead power transmission line having a central tension line including a fiber-reinforced composite material.

As shown in FIG. 1 , a conventional overhead power transmission line may include a central tension line 10 and a conductor wire 20 disposed on the periphery thereof, and the central tension line 10 is an inner layer made of a carbon fiber reinforced composite material. (11) and to suppress corrosion of the conductor wire 20 by dissimilar metal contact corrosion between (11) and the inner layer 11 and the conductor wire 20, that is, galvanic corrosion, made of a glass fiber reinforced composite material It may include an outer layer 12 made of.

However, in such a conventional overhead power transmission line, the high specific gravity of the glass fiber reinforced composite material constituting the outer layer 12 of the central tension line 10, for example, a specific gravity of about 2.0 g / ㎤ There is a limit to the weight reduction of the overhead power transmission line. and thus the ear canal characteristics may be deteriorated, and the conductor wire 20 disposed around the central tension line and in contact with and rubbing the outer layer 12 is damaged due to the high hardness of the glass fiber reinforced composite material, As a result, problems of increasing resistance and reducing power transmission amount due to a decrease in the cross-sectional area of the conductor line 20 may occur. In addition, there is a problem in that the manufacturing cost of the overhead power transmission line is increased by the application of the relatively expensive glass fiber reinforced composite material.

Therefore, the tensile strength of the central tension line is excellent, so it has excellent sag characteristics to prevent the overhead power transmission line from sagging downward, and the flexibility of the central tension line is sufficient to improve the workability of the wire and at the same time improve the workability of the central tension line. It is possible to suppress corrosion and damage of the disposed conductor wires, thereby avoiding or minimizing the increase in resistance of the overhead power transmission line and consequent reduction in the amount of power transmission, and a central tension line for overhead transmission lines that enables weight reduction and manufacturing cost reduction of the overhead transmission line There is an urgent need for an overhead power transmission line including this.

The present invention provides a central tension line for an overhead power transmission line that has excellent tensile strength and thus has excellent sag properties to prevent the overhead power transmission line from sagging downward and has sufficient flexibility to improve wiring workability, and an overhead power transmission line including the same aims to provide

In addition, the present invention can suppress corrosion and damage to the conductor wire disposed around the central tension line, thereby avoiding or minimizing the increase in the resistance of the overhead power transmission line and the reduction of the power transmission amount accordingly, and a central tension line for an overhead power transmission line comprising the same The purpose is to provide an overhead power transmission line.

Another object of the present invention is to provide a central tension wire for an overhead power transmission line that enables weight reduction and manufacturing cost reduction of the overhead power transmission line, and an overhead power transmission line including the same.

In order to solve the above problems, the present invention,

A central tension wire for an overhead power transmission line, comprising an inner layer comprising carbon fiber-reinforced plastic containing carbon fibers in a thermosetting resin matrix, and an outer layer comprising synthetic fiber-reinforced plastic enclosing the inner layer and containing synthetic fibers in a thermosetting resin matrix and, based on the total volume of the inner layer, the total volume ratio of the carbon fibers is greater than 75% and less than 85%, and based on the cross-sectional area at any cross-section of the central tension line, the cross-sectional area ratio of the inner layer is 73 to 83 %, and the cross-sectional area ratio of the outer layer is 17 to 27%, providing a central tension line for overhead power transmission lines.

Here, based on the total volume of the outer layer, the total volume ratio of the synthetic fibers provides a central tension line for overhead power transmission lines, characterized in that 50 to 85%.

In addition, the outer layer provides a central tension wire for an overhead power transmission line, characterized in that the hardness is 10 to 30 HV (Vickers hardness).

And, the synthetic fiber has a tensile strength of 0.01 to 1.0 GPa, an elastic modulus of 0.6 to 17 GPa, an elongation of 20% or more, and a shrinkage rate of less than 1.5% when maintained at 190 ° C. for 15 minutes. Provides joists.

Furthermore, the synthetic fiber provides a central tension line for an overhead power transmission line, characterized in that it comprises at least one selected from the group consisting of polyester fibers, nylon fibers, acrylic fibers and polyurethane fibers.

In addition, the thermosetting resin matrix provides a central tension line for overhead power transmission lines, characterized in that it contains a base resin having a glass transition temperature (Tg) of 205° C. or higher.

Here, the base resin provides a central tension wire for an overhead power transmission line, characterized in that it contains an epoxy resin.

On the other hand, the carbon fiber includes a high-strength continuous fiber having a diameter of 3 to 35 μm, a tensile strength of 3.5 to 5.0 GPa, an elastic modulus of 140 to 600 GPa, and a coefficient of thermal expansion of 0 μm/m° C. or less, characterized in that, We provide a center tension wire for overhead power transmission lines.

And, it provides a central tension wire for an overhead power transmission line, which wraps the outer layer and further comprises a cover layer made of a metal material having an electrical conductivity of 55 to 64% IACS.

Here, the metal material includes an aluminum material, and the thickness of the cover layer is 0.3 to 2.5 mm, and provides a central tension line for an overhead power transmission line.

In addition, it provides a central tension line for overhead power transmission line, characterized in that a gap is formed between the outer layer and the cover layer.

On the other hand, the central tension wire for the overhead power transmission line; And it provides an overhead power transmission line comprising a conductor in which a plurality of aluminum alloy or aluminum wire rods are combined, which is disposed around the central tension line for the overhead power transmission line.

Here, the aluminum alloy or aluminum wire may be made of 1000 series aluminum, and the tensile strength before heat treatment is 15 to 25 kgf/mm2 and the elongation is less than about 5%, the tensile strength after heat treatment is less than 9 kgf/mm2, and the elongation is It provides an overhead power transmission line, characterized in that about 20% or more.

In addition, on the surface of the aluminum alloy or aluminum wire, at least one surface hardness reinforcing layer selected from the group consisting of an aluminum oxide film, a plating film of nickel (Ni) or tin (Sn) or both of them is formed, processing, provide power lines.

And, the surface hardness reinforcing layer provides an overhead power transmission line, characterized in that it is additionally coated with a fluororesin polymer coating layer.

Furthermore, the thickness of the surface hardness reinforcing layer provides an overhead power transmission line, characterized in that 5 ㎛ or more.

On the other hand, the surface hardness reinforcing layer provides an overhead power transmission line, characterized in that the aluminum oxide film and the plating film are both formed, and the thickness ratio of the aluminum oxide film and the plating film is 3:1 to 5:1.

The central tension wire for an overhead power transmission line according to the present invention has excellent tensile strength through a combination of a carbon fiber layer and a synthetic fiber layer, and thus has excellent sag characteristics to prevent the overhead power transmission line from sagging downward, as well as sufficient flexibility. It shows an excellent effect of improving workability.

In addition, the central tension line for overhead power transmission line according to the present invention can suppress corrosion and damage of the conductor wire by the synthetic fiber layer with excellent insulating properties and its low hardness, thereby avoiding or minimizing the increase in the resistance of the overhead power line and the reduction in the amount of power transmission. It shows an excellent effect that can be done.

And, the central tension wire for overhead power transmission line according to the present invention exhibits an excellent effect of enabling weight reduction and manufacturing cost reduction of the overhead power transmission line by the synthetic fiber layer having low specific gravity and manufacturing cost.

1 schematically shows a cross-sectional structure of a conventional overhead power transmission line.
2 schematically shows a cross-sectional structure of an embodiment of a central tension line for an overhead power transmission line according to the present invention.
3 schematically shows a cross-sectional structure of another embodiment of a central tension line for an overhead power transmission line according to the present invention.
FIG. 4 schematically shows a cross-sectional structure of an overhead power transmission line according to the present invention including the central tension line shown in FIG. 2 .

Hereinafter, preferred embodiments of the present invention will be described in detail. However, the present invention is not limited to the embodiments described herein and may be embodied in other forms. Rather, the embodiments introduced herein are provided so that the disclosed subject matter may be thorough and complete, and that the spirit of the present invention may be sufficiently conveyed to those skilled in the art. Like reference numerals refer to like elements throughout.

2 schematically shows a cross-sectional structure of an embodiment of a central tension line for an overhead power transmission line according to the present invention.

As shown in FIG. 2 , the central tension line 100 for an overhead power transmission line according to the present invention may include an inner layer 110 disposed at the center and an outer layer 120 surrounding the inner layer 110 .

When an overhead power transmission line including a conductor line disposed around the central tension line 100 is erected between pylons, a tensile force is applied in the longitudinal direction of the central tension line 100 in the longitudinal direction of the overhead transmission line. Sufficient tensile strength can be secured by forming it to extend continuously.

The inner layer 110 may be formed of a fiber-reinforced plastic including carbon fibers 112 as reinforcing fibers in the thermosetting resin matrix 111 . The thermosetting resin matrix 111 has a glass transition temperature (Tg) of 205 ° C. or higher is a base resin such as an epoxy resin, an unsaturated polyester resin, a bis maleate resin, or a polyimide resin, preferably an epoxy resin, a curing agent, a curing accelerator , and may be formed by adding an additive such as a release agent. When the glass transition temperature (Tg) of the base resin is less than 200°C, the heat resistance of the central tension line 100 is insufficient and thus cannot be applied to an overhead power transmission line having an operating temperature of about 180°C.

On the other hand, the glass transition temperature (Tg) of the base resin may be evaluated using a DMA (Dynamic Maechanical Analyzer), and the evaluation equipment may use a DMA equipment of TA Instruments, but is not limited thereto.

In particular, the epoxy resin may include a diglycidyl ether bisphenol A type epoxy resin, a polyfunctional epoxy resin, a diglycidyl ether bisphenol F type resin, and the like, and preferably a mixture of these three types of epoxy resins. may include When the above three types of epoxy resins are mixed and used, heat resistance can be improved, flexural properties and flexibility can be improved relatively compared to the case of using diglycidyl ether bisphenol A-type epoxy resin alone.

The curing agent is an acid anhydride-based curing agent such as methyl tetrahydrophthalic anhydride (MTHPA), tetrahydrophthalic anhydride (THPA), hexahydrophthalic anhydride (HHPA), or nadic methyl anhydride (NMA). , preferably methyl tetrahydrophthalic anhydride or nadic methyl anhydride, or an alicyclic polyamine-based compound such as mentaindiamine (MDA), isoprondiamine (IPDA), diaminodiphenylsulfone (DDS) , an amine-based curing agent such as an aliphatic amine-based compound such as diaminodiphenylmentane (DDM) may include a liquid curing agent.

Based on 100 parts by weight of the base resin, the content of the acid anhydride-based curing agent may be 70 to 150 parts by weight, the content of the amine-based curing agent may be 20 to 50 parts by weight, and the content of the acid anhydride-based curing agent is 70 parts by weight If the content of the amine-based curing agent is less than 20 parts by weight, heat resistance may be reduced due to insufficient curing during curing of the thermosetting resin matrix, and the content of the acid anhydride-based curing agent is greater than 150 parts by weight or the amine-based curing agent When the content of is more than 50 parts by weight, the unreacted curing agent remains in the thermosetting resin matrix and acts as an impurity, thereby reducing the heat resistance and other physical properties of the thermosetting resin matrix.

The curing accelerator accelerates the curing of the thermosetting resin matrix 111 by the curing agent. When the curing agent is an acid anhydride curing agent, an imidazole curing accelerator is used, and when the curing agent is an amine curing agent, boron trifluoride is used. It is preferable to use an ethylamine-based curing accelerator.

Based on 100 parts by weight of the base resin, the content of the imidazole-based curing accelerator is 1 to 3 parts by weight, the content of the boron trifluoride ethylamine-based curing accelerator may be 2 to 4 parts by weight, and the imidazole-based curing accelerator When the content of the curing accelerator is less than 1 part by weight or the content of the boron trifluoride ethylamine-based curing accelerator is less than 2 parts by weight, the fully cured thermosetting resin matrix 111 cannot be obtained, whereas the imidazole-based curing accelerator When the content is more than 3 parts by weight or the content of the boron trifluoride ethylamine-based curing accelerator is more than 4 parts by weight, the curing time is shortened at a fast reaction rate and the viscosity of the thermosetting resin matrix 111 is rapidly increased, so workability There is a problem of this deterioration.

The release agent serves to facilitate the molding process by reducing the frictional force with the molding die during molding of the thermosetting resin matrix 111 , and for example, zinc stearate and the like may be used.

Based on 100 parts by weight of the base resin, the content of the release agent may be 1 to 5 parts by weight, and when the content of the release agent is less than 1 part by weight, the workability of the thermosetting resin matrix 111 may be reduced, whereas 5 When the amount is more than 1 part by weight, the workability of the thermosetting resin matrix 111 cannot be further improved and only the manufacturing cost is increased.

The carbon fiber 112 is a high-strength continuous fiber having a diameter of 3 to 35 μm, and has a tensile strength of 3.5 to 5.0 GPa, an elastic modulus of 140 to 600 GPa, and a coefficient of thermal expansion close to 0 or less than 0 μm/m°C. have. When the diameter of the carbon fiber is less than 3 μm, manufacturing is difficult and uneconomical, whereas when it exceeds 35 μm, tensile strength may be greatly reduced.

The carbon fiber 112 may be surface-treated to improve compatibility with the base resin of the thermosetting resin matrix 111 . The coupling agent for treating the surface of the carbon fiber 112 is not particularly limited as long as it can treat the surface of the high-strength fiber. For example, it may include a titanate-based, silane-based, or zirconate-based coupling agent. and these may be used alone or in combination of two or more.

A plurality of reactors are introduced to the surface of the carbon fiber surface-treated with the coupling agent, and these reactors react with the polymer resin to prevent aggregation between fibers, thereby removing bubbles or defects affecting the physical properties of the final product. , thereby improving the interfacial bonding property between the high-strength carbon fiber and the thermosetting resin and the dispersibility of the high-strength carbon fiber.

The total volume ratio of the carbon fibers 112 may be greater than 75% and less than 85%, preferably 78 to 83%, based on the total volume of the inner layer 110 . Here, the total volume ratio of the carbon fibers 112 may be defined as follows.

Total volume ratio of carbon fiber (%) = (total volume of carbon fiber/total volume of inner layer) * 100

Here, when the volume ratio of the carbon fiber 112 is 75% or less, the tensile strength of the central tension line 100 is insufficient, so that the ear canal characteristics before overhead transmission and transmission may be deteriorated, whereas when it is 85% or more, the central tension line 100 Insufficient flexibility of (100) may reduce the workability of the overhead power transmission line, and the aggregation between carbon fibers may increase, resulting in bubbles or cracking inside the inner layer 110, which may significantly decrease physical properties and workability. have.

The outer layer 120 may be formed of a fiber-reinforced plastic including synthetic fibers 121 in a thermosetting resin matrix. The thermosetting resin matrix may be the same as the thermosetting resin matrix 111 of the inner layer 110 .

The outer layer 120 is provided between the inner layer 110 including carbon fiber and the conductor wire disposed on the periphery of the central tension line 100 to prevent dissimilar metal contact corrosion therebetween. , by improving the flexibility of the central tension line 100 to improve the wiring workability of the overhead power transmission line, and by a relatively low specific gravity, for example, a specific gravity of about 1.55 g / ㎤ And a relatively low hardness, for example, 10 to 30 HV (Vickers hardness) by the hardness of the outer layer 120, and performs a function of avoiding or minimizing damage to the conductor wires rubbing each other.

The synthetic fiber 121 may have a tensile strength of 0.01 to 1.0 GPa, an elastic modulus of 0.6 to 17 GPa, particularly an elongation of 20% or more, and a shrinkage rate of less than 1.5% when maintained at 190°C for 15 minutes. That is, since the synthetic fiber has a sufficient elongation, it contributes to the improvement of flexibility so that the bending characteristics of the central tension line 100 can be secured, and the shape can be maintained without shrinking even in the high-temperature process of forming the outer layer 120 . The synthetic fibers 121 may include, for example, polyester fibers, nylon fibers, acrylic fibers, polyurethane fibers, and the like.

The total volume ratio of the synthetic fibers 121 may be 50 to 85%, preferably 70 to 75%, based on the total volume of the outer layer 120 . Here, the total volume ratio of the synthetic fibers 121 may be defined as follows.

Total volume ratio of synthetic fibers (%) = (total volume of synthetic fibers/total volume of outer layer) * 100

Here, if the volume ratio of the synthetic fiber 121 is less than 50%, the flexibility of the central tension line 100 may be insufficient, so that the workability of the overhead power transmission line may be reduced, whereas if it exceeds 85%, aggregation between synthetic fibers As the phenomenon is increased, bubbles or cracks may occur inside the outer layer 120 , thereby greatly reducing physical properties and workability.

In addition, the central tension line in which the volume ratio of the synthetic fiber in the outer layer is precisely controlled to 50% to 85% does not damage the aluminum conductor surrounding the central tension line by friction with the hardness of the outer layer being less than 40 HV, which is the aluminum hardness. . On the other hand, the central tension line in which the volume ratio of synthetic fibers exceeds 85% in the outer layer damages the aluminum conductor surrounding it by friction, and the central tension line in which the volume ratio of the fiber-containing fibers in the outer layer is less than 50% is a problem in that the physical properties are deteriorated there is

Based on the cross-sectional area at any cross-section of the central tension line 100 composed of the inner layer 110 and the outer layer 120 , the cross-sectional area ratio of the inner layer 110 may be 73 to 83%, and the outer layer 120 . ) may have a cross-sectional area ratio of 17 to 27%. Here, the cross-sectional area ratio of the inner layer 110 and the cross-sectional area ratio of the outer layer 120 may be defined as follows.

Cross-sectional area ratio of inner layer (%) = (cross-sectional area of inner layer / cross-sectional area at any cross-section of the central tension line) * 100

Cross-sectional area ratio of outer layer (%) = (cross-sectional area of outer layer / cross-sectional area at any cross-section of the central tension line) * 100

Here, when the cross-sectional area ratio of the inner layer 110 is less than 73% and the cross-sectional area ratio of the outer layer 120 is more than 27%, the tensile strength of the central tension line 100 is insufficient, so that the ear canal characteristic before overhead transmission is lowered On the other hand, when the cross-sectional area ratio of the inner layer 110 is more than 83% and the cross-sectional area ratio of the outer layer 120 is less than 17%, the flexibility of the central tension line 100 is insufficient, so that the overhead power transmission line workability is insufficient. may be lowered.

3 schematically shows a cross-sectional structure of another embodiment of a central tension line for an overhead power transmission line according to the present invention.

As shown in FIG. 3 , the central tension line 100 according to the present invention may further include a cover layer 140 surrounding the outer layer 120 . Here, the cover layer 140 may have a configuration included in the central tension line 100 , but may also have a configuration included in the conductor together with the aluminum wire 200 to be described later.

The cover layer 140 can further suppress damage to the conductor wire due to contact and friction between the outer layer 120 and the conductor wire, and has excellent electrical conductivity, for example, electrical conductivity of 55 to When it is made of a 64% IACS metal material, preferably the same aluminum material as the conductor wire, it conducts electricity with the conductor wire disposed around the central tension line 100, thereby reducing the overall resistance of the overhead power transmission line and consequently improving the power transmission amount can be additionally performed.

Here, the thickness of the cover layer 140 may be 0.3 to 2.5 mm, and when the thickness of the cover layer 140 is less than 0.3 mm, the effect of reducing the overall resistance of the overhead power transmission line is insignificant, whereas when it exceeds 2.5 mm, the central There is a difficulty in manufacturing the joist 100, and since the outer diameters of the inner layer 110 and the outer layer 120 are reduced based on the central tension line 100 of the same outer diameter, the tensile strength of the central tension line 100 is increased. It is degraded and there is a problem that the low-acidity characteristic cannot be implemented.

When the central tension line 100 further includes the cover layer 140 , a gap 130 may be formed between the outer layer 120 and the cover layer 140 . The cover layer 140 may be formed by a method such as conform extrusion of a metal rod such as aluminum or welding a metal tape such as aluminum, and in particular, through the conform extrusion of an aluminum rod, the cover layer ( 140) can be formed, so that the cover layer 140 can be formed in a long length, thereby not only improving productivity, but also making it easy to form and control the gap 130 .

In addition, in the case of confirm extrusion, since the cover layer 140 having a continuously formed surface without a seam such as a welding portion can be formed, the center tension line 100 or an overhead power transmission line having the same can be manufactured, erected or erected after It is possible to prevent galvanic corrosion from occurring due to damage to the seam due to bending stress acting on the central tension line 100 .

The cover layer 140 and the gap 130 may be formed by extruding a metal material or the like in the form of a tube. Specifically, the metal material surrounding the outer layer 120 and having an inner diameter greater than the outer diameter of the outer layer 120 is extruded and formed in a tube shape, and then the diameter is reduced in stages to form the cover layer 140, , the size of the gap 130 may be adjusted, and for example, the total cross-sectional area of the gap 130 may be about 0.15 to 7.1 mm 2 .

Therefore, it is possible to prevent the deterioration of the outer layer 120 by suppressing the transfer of heat during the confirmation extrusion of the aluminum rod for the formation of the cover layer 140 to the outer layer 120 , as well as the overhead power transmission line. When a bending stress is applied to the central tension line 100 for the inner layer 110 , the outer layer 120 and the cover layer 140 due to the gap 130 , the inner layer 110 and the outer layer 120 and the cover layer 140 separately behave. Most of the stress is applied to the inner layer 110 and the outer layer 120 including fiber-reinforced plastic wire rods having relatively high tensile strength to realize low-conductivity characteristics of the overhead power transmission line, and at the same time, aluminum having relatively low tensile strength. By minimizing the stress applied to the cover layer 140 made of a material or the like, it is possible to suppress the damage of the central tension line 100 when winding a bobbin, a drum, a pulley, etc. for manufacturing or erection of an overhead power transmission line.

FIG. 4 schematically shows a cross-sectional structure according to an embodiment of an overhead power transmission line according to the present invention including the central tension line shown in FIG. 2 .

As shown in FIG. 4 , the overhead power transmission line according to the present invention may be formed by arranging a conductor in which a plurality of aluminum alloys or aluminum wires 200 are combined around the central tension line 100 .

The aluminum wire 200 may be made of 1000 series aluminum or an aluminum-zinc alloy such as 1050, 1100, 1200, etc., and the tensile strength before heat treatment is about 15 to 25 kgf / mm 2 and the elongation is less than about 5%, and after heat treatment The tensile strength may be less than about 9 kgf/mm 2 and the elongation may be about 20% or more.

In addition, the aluminum wire 200 has a trapezoidal cross section, and the area ratio of the conductor is significantly increased compared to the aluminum wire of the conventional overhead power transmission line having a circular cross section, thereby maximizing the power transmission amount and power transmission efficiency of the overhead power transmission line. For example, a conventional conductor including an aluminum wire having a circular cross-section may have an area ratio of about 75%, whereas a conductor including an aluminum wire having a trapezoidal cross-section may have an area ratio of about 95% or more.

The aluminum wire 200 may have a trapezoidal cross-section by confirmation extrusion or wire drawing using a trapezoidal die. When the aluminum wire 200 is formed by confirm extrusion, a separate heat treatment is unnecessary because it is naturally heat-treated during the extrusion process.

The aluminum wire 200 is heat-treated in the conform extrusion process or is subsequently heat-treated after drawing, so that it is possible to release a region where stress is concentrated that is formed in the aluminum structure by torsion in the extrusion or drawing process, etc. and prevents the flow of electrons. , whereby the electrical conductivity of the aluminum wire 200 is improved, and as a result, the power transmission amount and power transmission efficiency of the overhead power transmission line can be improved.

The cross-sectional area and number of the aluminum wire 200 may be appropriately selected according to the standard of the overhead power transmission line, for example, the cross-sectional area of the aluminum wire 200 may be 3.14 to 50.24 mm 2 , and the cross-section is trapezoidal aluminum When the wire 200 is converted into an aluminum wire having the same cross-sectional area and a circular cross-section, the converted aluminum wire may have a cross-sectional diameter of 2 to 8 mm.

In addition, the number of the aluminum wire 200 may be, for example, 12 to 40, and preferably may have a multilayer structure including 8 in the inner layer and 12 in the outer layer.

As described above, the aluminum wire 200 may be heat-treated to improve electrical conductivity. When heat-treated in this way, the surface becomes vulnerable to scratches due to softening, so during the manufacturing, transportation, and construction of the overhead power line, external A number of scratches may be generated on the surface of the aluminum wire 200 by the pressure or impact of

Accordingly, the aluminum wire 200 may have a surface hardness reinforcing layer formed on the surface to suppress the generation of scratches on the surface. Preferably, the thickness of the surface hardness reinforcing layer may be 5 μm or more, preferably more than 10 μm and less than or equal to 50 μm. When the thickness of the surface hardness reinforcing layer is less than 5 μm, the surface hardness of the aluminum wire 200 cannot be sufficiently improved. While a number of scratches may be generated on the surface of 200, if the thickness exceeds 50 μm, the surface hardness reinforcing layer may be locally damaged or cracks may occur when bending, such as when the overhead power transmission line is wound on a bobbin.

Furthermore, the aluminum wire 200 has the surface hardness reinforcing layer formed on its surface to further improve the tensile strength of the overhead power transmission line, and as a result, the sag of the overhead power transmission line can be further suppressed.

The surface hardness reinforcing layer may be formed on the entire surface of the plurality of aluminum wires 200 constituting the overhead power transmission line, and preferably, the aluminum wires 200 present in the outermost layer among the plurality of aluminum wires 200 . It may be formed on the entire surface of each, and more preferably, it may be formed on the outer surface forming the outer periphery of the overhead power transmission line among the surfaces of each of the aluminum wire rods 200 present in the outermost layer.

The surface hardness reinforcing layer is not particularly limited as long as it can suppress scratch generation by improving the hardness of the surface of the aluminum wire 200, for example, an aluminum oxide film formed by anodizing treatment, or nickel (Ni) ), and may include a plating film such as tin (Sn).

Specifically, the anodizing treatment method of the surface of the aluminum wire 200 includes degreasing to remove organic contaminants such as oils and fats present on the surface of the aluminum wire 200, and washing the surface of the aluminum wire 200 with clean water. (rinsing), etching to remove aluminum oxide present on the surface of the aluminum wire 200 with sodium hydroxide, etc., and desmutting to dissolve and remove alloy components remaining on the surface of the aluminum wire 200 after etching ), rinsing to clean the surface of the aluminum wire 200 again with clean water, and anodizing performed while applying a voltage of 20 to 40 V to form a dense and stable aluminum oxide film on the surface of the aluminum wire 200 ), washing the surface of the aluminum wire 10 again with clean water (rinsing), air drying at room temperature, etc. may include processes such as drying.

When the surface hardness reinforcing layer includes an aluminum oxide film by anodizing, since the insulating property of the aluminum oxide film is excellent, power loss can be reduced due to the insulating effect between the aluminum wires 200, and the aluminum oxide Due to the high radiation characteristics of the film, the current capacity can be increased by rapidly discharging Joule heat generated during power transmission to the atmosphere.

In addition, the surface hardness reinforcing layer may be additionally coated with a polymer resin such as a fluororesin. The polymer resin imparts a super water-repellent effect to the aluminum oxide film, thereby suppressing the adsorption of dust or contaminants in the air on the surface of the overhead power transmission line, accumulation of snow in winter, or generation of ice.

The surface hardness reinforcing layer may include both an aluminum oxide film by anodizing and a plating film such as nickel (Ni), tin (Sn), or the like. When the surface hardness reinforcing layer includes both an aluminum oxide film and a plating film, the aluminum oxide film may be disposed on a lower portion and the plating film may be disposed on the aluminum oxide film, and the aluminum oxide film and the plating film The thickness ratio of may be about 3:1 to 5:1.

When the thickness ratio of the aluminum oxide film and the plating film is 3:1 to 5:1, the hardness of the surface of the aluminum wire 200 can be sufficiently improved by the aluminum oxide film which is relatively thick and has an excellent effect of improving the surface hardness. At the same time, when the overhead power transmission line is bent, such as being wound on a bobbin, by the plating film, which is disposed on the outside and has a relatively low risk of cracking and damage due to bending, local cracks, damage, etc. of the surface hardness reinforcing layer can be effectively suppressed.

[Example]

1. Evaluation of physical properties according to the ratio of the cross-sectional area between the inner and outer layers of the central tension line

As shown in Table 1 below, the tensile strength and flexural properties of the central tension line according to the cross-sectional area ratio of the inner layer and the outer layer were evaluated. The inner layer is made of fiber-reinforced plastic having a volume ratio of carbon fibers of 79%, and the outer layer is made of fiber-reinforced plastic having a volume ratio of polyester (PET) fibers of 75%. In Table 1 below, the bending inner diameter means the average value of the inner diameter that can be formed at the bend when the central tension line is bent by 180°, and the flexural characteristic is the value obtained by dividing the bending inner diameter (mm) by the total outer diameter (mm) The smaller the characteristic, the better the flexibility.

full outer diameter
(mm) outer layer thickness
(mm) inner layer cross-sectional area
ratio(%) outer layer cross-sectional area
ratio(%) tensile strength
(MPa) bend inner diameter
(mm) Flexural characteristics
Comparative Example 1 8.5 0.21 90 10 2,988 527.0 62 Comparative Example 2 8.5 0.30 86 14 2,900 527.0 62 Comparative Example 3 8.5 0.33 85 15 2,872 518.5 61 Example 1 8.5 0.38 83 17 2,824 510.0 60 Example 2 8.5 0.40 82 18 2,805 510.0 60 Example 3 8.5 0.50 78 22 2,713 476.0 56 Example 4 8.5 0.60 74 26 2,623 442.0 52 Example 5 8.5 0.63 73 27 2,600 425.0 50 Comparative Example 4 8.5 0.70 70 30 2,535 416.5 49

As shown in Table 1, the central tension line of Examples 1 to 5 satisfies both tensile strength and flexibility through adjustment of the cross-sectional area ratio of the inner layer and the outer layer, whereas the central tension line of Comparative Examples 1 to 3 showed less flexibility. It was confirmed that the tensile strength of the central tension line of Comparative Example 4 was significantly lowered.

2. Evaluation of physical properties according to the volume ratio of carbon fibers in the inner layer of the central tension line

As shown in Table 2 below, the tensile strength and flexural properties of the central tension line according to the volume ratio of carbon fibers in the inner layer were evaluated. The outer layer of the central tension line is made of fiber-reinforced plastic with a volume ratio of 75% polyester (PET) fibers. In Table 2 below, the bending inner diameter means the average value of the inner diameter that can be formed at the bend when the central tension line is bent by 180°, and the flexural characteristic is the value obtained by dividing the bending inner diameter (mm) by the overall outer diameter (mm) The smaller the characteristic, the better the flexibility.

full outer diameter
(mm) outer layer thickness
(mm) carbon fiber
Volume ratio (%) thermosetting resin
matrix
Volume ratio (%) tensile strength
(MPa) bend inner diameter
(mm) Flexural characteristics Comparative Example 5 8.5 0.63 75 25 2,098 416.5 49 Example 6 8.5 0.63 78 22 2,474 425.0 50 Example 7 8.5 0.63 79 21 2,600 425.0 50 Example 8 8.5 0.63 81 19 2,725 484.5 57 Example 9 8.5 0.63 82 18 2,850 510.0 60 Example 10 8.5 0.63 83 17 2,976 535.5 63 Comparative Example 6 8.5 0.63 85 15 3,227 544.0 64

As shown in Table 2, the central tension line of Examples 6 to 10, in which the volume ratio of carbon fibers in the inner layer was precisely controlled, had sufficient tensile strength and flexibility, while the central tension line of Comparative Example 5 had the carbon fiber volume ratio While the tensile strength was significantly lowered due to the substandard, the central tensile line of Comparative Example 6 was confirmed to have insufficient flexibility due to the carbon fiber volume ratio exceeding the standard.

3. Hardness evaluation of the outer layer of the central tension line

The hardness of the central tension line according to the volume ratio of the synthetic fibers in the outer layer as shown in Table 3 below was evaluated.

The hardness is the Vickers hardness (HV), and when a diamond press in the form of a right-angled pyramid having a square base with a prescribed angle (between angle) between the vertices and faces facing each other is 136 degrees, pressed into the surface of the test piece with a test load, the presser It was measured by dividing the surface area of the indentation indentation concave part.

HV = test load (F) / surface area of indentation (S)

Volume percentage of synthetic fibers (%) Hardness (HV) of the outer layer of the central tension line Comparative Example 7 45 7 Example 11 50 10 Example 12 53 13 Example 13 58 16 Example 14 60 17 Example 15 64 19 Example 16 70 22 Example 17 75 25 Example 18 85 30 Comparative Example 8 90 40

As shown in Table 3, the central tension line of Examples 11 to 18, in which the volume ratio of the synthetic fiber in the outer layer is precisely controlled, is less than 40 HV, which is the aluminum hardness of the outer layer. While not expected to be damaged by friction, the central tension line of Comparative Example 8, in which the volume ratio of synthetic fibers in the outer layer exceeds the standard, damages the aluminum conductor surrounding it by friction, and the volume ratio of the synthetic fibers in the outer layer is The central tension line of Comparative Example 7, which is less than the standard, is expected to decrease in physical properties.

Although the present specification has been described with reference to preferred embodiments of the present invention, those skilled in the art can variously modify and change the present invention without departing from the spirit and scope of the present invention as set forth in the claims described below. will be able to carry out Therefore, if the modified implementation basically includes the elements of the claims of the present invention, all of them should be considered to be included in the technical scope of the present invention.

100: center tension line 200: conductor wire

Claims (18)

As a central tension wire for overhead power transmission lines,
An inner layer comprising carbon fiber-reinforced plastic containing carbon fibers in a thermosetting resin matrix, and
and an outer layer comprising a synthetic fiber-reinforced plastic enclosing the inner layer and containing synthetic fibers in a thermosetting resin matrix,
based on the total volume of the inner layer, the total volume fraction of the carbon fibers is greater than 75% and less than 85%;
Based on the cross-sectional area in any cross-section of the central tension line, the cross-sectional area ratio of the inner layer is 73 to 83%, and the cross-sectional area ratio of the outer layer is 17 to 27%. According to claim 1,
Based on the total volume of the outer layer, the total volume ratio of the synthetic fiber is 50 to 85%, characterized in that the central tension line for overhead power transmission line. 3. The method of claim 2,
The outer layer has a hardness of 10 to 30 HV (Vickers hardness), characterized in that, a central tension wire for overhead power transmission line. 3. The method of claim 2,
The synthetic fiber has a tensile strength of 0.01 to 1.0 GPa, an elastic modulus of 0.6 to 17 GPa, an elongation of 20% or more, and a shrinkage rate of less than 1.5% when maintained at 190°C for 15 minutes, a central tension line for an overhead power transmission line. 3. The method of claim 2,
The synthetic fibers are polyester fibers, nylon fibers, acrylic fibers and polyurethane fibers, characterized in that it comprises at least one selected from the group consisting of, the central tension wire for overhead power transmission lines. 6. The method according to any one of claims 1 to 5,
The thermosetting resin matrix has a glass transition temperature (Tg) of 205 ° C. or higher, characterized in that it comprises a base resin, a central tension wire for an overhead power transmission line. 7. The method of claim 6,
The base resin is characterized in that it comprises an epoxy resin, a central tension wire for an overhead power transmission line. 5. The method according to any one of claims 1 to 4,
The carbon fiber includes a high-strength continuous fiber having a diameter of 3 to 35 μm, a tensile strength of 3.5 to 5.0 GPa, an elastic modulus of 140 to 600 GPa, and a coefficient of thermal expansion of 0 μm/m° C. or less, overhead power transmission line Dragon central tension line. 5. The method according to any one of claims 1 to 4,
A central tension wire for overhead power transmission lines, which surrounds the outer layer and further comprises a cover layer made of a metal material having an electrical conductivity of 55 to 64% IACS. 10. The method of claim 9,
The metal material includes an aluminum material,
The thickness of the cover layer, characterized in that 0.3 to 2.5 mm, overhead power transmission line for the central tension line. 10. The method of claim 9,
A central tension line for overhead power transmission lines, characterized in that a gap is formed between the outer layer and the cover layer. The central tension line for an overhead power transmission line of any one of claims 1 to 5; and
An overhead power transmission line comprising a conductor in which a plurality of aluminum alloys or aluminum wires disposed around the central tension line for the overhead power transmission line are combined. 13. The method of claim 12,
The aluminum alloy or the aluminum wire rod may be made of 1000 series aluminum, the tensile strength before heat treatment is 15 to 25 kgf/mm2, the elongation is less than about 5%, the tensile strength after heat treatment is less than 9 kgf/mm2, and the elongation is about 20 % or more, the overhead power transmission line. 13. The method of claim 12,
An overhead power transmission line, characterized in that at least one surface hardness reinforcing layer selected from the group consisting of an aluminum oxide film, a plating film of nickel (Ni) or tin (Sn) or both of them is formed on the surface of the aluminum alloy or aluminum wire. 13. The method of claim 12,
The aluminum alloy or the aluminum wire is characterized in that the cross-section of the trapezoidal shape, overhead power transmission line. 16. The method of claim 15,
The surface hardness reinforcing layer is characterized in that it is additionally coated with a fluororesin polymer coating layer, overhead power transmission line, 16. The method of claim 15,
An overhead power transmission line, characterized in that the thickness of the surface hardness reinforcing layer is 5 ㎛ or more. 16. The method of claim 15,
The surface hardness reinforcing layer is formed with both the aluminum oxide film and the plating film,
The overhead power transmission line, characterized in that the thickness ratio of the aluminum oxide film and the plating film is 3:1 to 5:1.

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