KR20150037068A - Overhead Conductor using Ultra High Strength Steel Wire - Google Patents

Abstract

The present invention relates to an overhead transmission cable using an ultra high strength steel wire. The present invention includes a steel core having a plurality of steel wires, which contains C 0.88~1.0 wt%, Si 1.1~1.5 wt%, Mn 0.3~0.7 wt%, P 0.001~0.025 wt%, S 0.001~0.025 wt%, Cu 0.001~0.3 wt%, and Cr 0.2~0.95 wt%, and Fe alloy for the rest portion; and an Al wire which surrounds the steel core. Therefore, the overhead transmission cable using an ultra high strength steel wire is used as a steel core. Thus, low stress transition temperature is obtained. Sag is reduced. Power transmission is increased.

Description

Technical Field [0001] The present invention relates to an ultra high strength steel wire,

More particularly, the present invention relates to a machined transmission line using an ultra-high strength steel wire with a high strength, and more particularly, to a steel wire having a low stress transition temperature by applying an ultra high strength steel wire having a high tensile strength as a steel material, To a machined transmission line using an ultra-high strength steel wire which is increased in transmission capacity due to reduction of the islands.

According to the KEPCO Standard Specification for Purchase (ES 121-113 ~ 160), the conventional ACSR (Aluminum Stranded Conductors Steel Reinforced Steel) is composed of seven strands of high carbon steel wire stranded in a steel core for supporting the transmission line .

The diameter of the steel wire depends on the type of transmission line. For details, please refer to KEPCO standard purchase specifications. And this time, the high tensile strength of the carbon steel wire has been required a characteristic value of about 125 ~ 135kgf / mm ^2, when the aluminum wire is the tensile strength may be used in the 16.2 ~ 16.5 kgf / mm ^2.

On the other hand, the core material constituting the working transmission line is composed of aluminum wire which is responsible for maintaining the strength of the wire and carrying the current.

In the case of overhead transmission lines, the current is mainly carried by the aluminum wire rod, and the steel bridge composed of the steel wire serves as a supporting line for pulling the wire from the steel tower or the electric pole. That is, in the case of a working transmission line, when a wire is installed in a steel tower or a telephone pole according to various characteristics of a constituent material such as a steel wire, deflection becomes different, and the deflection of the wire is digitized.

As shown in Fig. 1, when there is no difference in elevation between the supporting points of the steel towers, the diagrams of the electric wires can be simply expressed as follows.

Where D is the isodose, S is the span, T is the horizontal tension applied to the wire, and W is the composite load applied to the wire.

As can be seen from the above equation, it can be seen that D increases when T, i.e., the horizontal tension applied to the wire is large. That is, the horizontal tension of the wire can be made larger as the horizontal tension applied to the wire is made larger.

Since the machined transmission line is basically made of a metal material, the length change due to the linear expansion coefficient is caused by the temperature change. In other words, in the summer, the transmission line becomes longer and longer, and in winter, the length of the transmission line decreases. Therefore, a constant angle is necessary to protect the transmission line against this length change.

As described above, the machined transmission line is basically composed of an aluminum wire having a constant diameter and a steel wire having a constant diameter. The current is mainly carried by the aluminum wire, and the steel wire serves as a support line for fixing the wire to the steel tower.

In the case of machined transmission lines, two kinds of wire materials having different characteristics (tensile strength and linear expansion coefficient) are compositely stranded. That is, when a constant tensile force is applied to the machined transmission line, the aluminum wire and the steel wire share a certain tension simultaneously at room temperature, and when the wire temperature rises over a certain temperature, the coefficient of linear expansion of the aluminum wire becomes much larger than the coefficient of linear expansion Therefore, all of the tensile force shared by aluminum is moved to the steel wire, and the temperature at this time is referred to as a transition temperature (Knee point). In other words, the deviation in the temperature range above the transition temperature is influenced by the linear expansion coefficient and the elastic modulus of pure steel, and the gyration in the temperature region below the transition temperature is dominated by the composite characteristics in the composite strand of aluminum and steel wire .

In general, in the case of a working transmission line, when comparing the length change in the temperature region below or above the transition temperature, the change in length at or below the transition temperature is considerably larger than the change in length over the transition temperature. That is, the composite linear expansion coefficient of the aluminum wire and the steel wire below the transition temperature is larger than the single linear expansion coefficient of the steel wire at the transition temperature or more.

Such a phenomenon means that, in the case of synthetic stranded wire such as a working transmission line, when the transition temperature is lowered, the change in the mounting of the transmission line due to the temperature increase can be reduced. If the roadway decreases, the transmission capacity can be further increased by the decrease.

Therefore, by appropriately controlling the transition temperature of the machining power transmission line, it is possible to increase or decrease the transmission capacity. Therefore, an understanding of the factors affecting the transition temperature is required. The transition temperature is varied by a wide variety of factors.

Generally, the transition temperature depends on factors such as the span of the steel tower, the wire tension, the difference in the linear expansion characteristics between aluminum and steel wire, and the cross sectional area ratio of the two components. In the case of a composite strand such as a machined transmission line, how much initial tension is distributed to the initial aluminum wire from the viewpoint of the wire itself, except for the exogenous factors affecting the transmission line of the transmission line, is a very important factor . In other words, it is a key element technology to keep the transition temperature low by designing that the tension is not applied to the aluminum wire as much as possible. In order to achieve the above object, it is required to minimize the tension sharing ratio applied to the aluminum wire, which is an important measure to increase the tensile strength of the steel wire. Therefore, maximizing the tensile strength of the steel material formed by the steel wire, that is, maximizing the tensile strength of the steel material, the transition temperature can be lowered.

Korean Patent Application Publication No. 10-2004-0064765 (published date: July 21, 2004) Korean Patent Application Publication No. 10-2002-0029539 (published date: April 19, 2002)

SUMMARY OF THE INVENTION Accordingly, the present invention has been made to solve the above-mentioned problems occurring in the prior art, and it is an object of the present invention to provide a high strength steel wire having a high tensile strength, It is an object of the present invention to provide a machining power transmission line using an ultra-high strength steel wire which is increased in power transmission capacity due to reduction of islands,

In order to accomplish the above object, the present invention provides a steel sheet comprising a plurality of steel wires stranded, wherein each steel wire comprises C 0.88 to 1.0%, Si 1.1 to 1.5%, Mn 0.3 to 0.7%, P 0.001 to 0.025% 0.001 to 0.025% of Cu, 0.001 to 0.3% of Cu, 0.2 to 0.95% of Cr, and the balance of Fe, and having a super high strength plated steel wire; And an aluminum wire rod surrounding the steel core. The present invention is directed to a machining power transmission line using a super high strength steel wire as a core.

Preferably, the plated steel wire is galvanized or zinc-aluminum-micro metal alloy plated or aluminum coated steel wire.

It is preferable that the aluminum wire rod is a heat-treated aluminum wire rod.

It is preferable that the aluminum wire rod is formed of a trapezoidal aluminum wire strand in a cross-section so as to surround the steel core in multiple layers.

It is preferable that the aluminum wire rod is formed of a circular aluminum wire in a cross section so as to surround the steel wire in multiple layers.

Accordingly, by applying an ultra-high strength steel wire having a high tensile strength as a steel material, it has a low stress transition temperature, thereby reducing the sag and increasing the transmission capacity due to reduction of the islands.

When using the present invention, ultra-high strength steel of a tensile strength of 180~250 kgf / mm ² range, unlike when using the conventional steel wire in the range of 130~135 kgf / mm ² in tensile strength due to the arrangement as a reinforced steel material , The tension sharing ratio of the aluminum wire rod is greatly reduced regardless of the difference in the tensile strength of the aluminum wire rod and the stress transient temperature is lowered thereby reducing the sag and increasing the transmission capacity have.

FIG. 1 is a schematic view showing the state of the art according to the prior art,
FIG. 2 is a cross-sectional view of a machined transmission line employing an ultra-high strength alloy-plated steel wire and a heat-treated trapezoidal aluminum wire according to the present invention,
3 is a cross-sectional view of a machined transmission line employing a super high strength alloy-plated steel wire and a circular aluminum wire as a core material according to the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS FIG.
1: Steel wire 2: Trapezoidal aluminum wire rod
3: Circular aluminum wire rod 10:
20, 30: aluminum wire rod

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 2 is a cross-sectional view of a machined transmission line employing an ultra-high strength alloy coated steel wire and a heat treated trapezoidal aluminum wire according to the present invention. FIG. 3 is a cross-sectional view of a super high strength alloy- Fig. 3 is a cross-sectional view of a working power transmission line employing a circular aluminum wire.

≪ Embodiment 1 >

As shown in the drawing, the working transmission line of the first embodiment of the present invention comprises: a core 10 in which a plurality of steel wires 1 of super-high strength plated steel wire are stranded; And an aluminum wire rod 20 surrounding the core 10 from the outside.

Each of the steel wires 1 should be galvanized or zinc-aluminum-micro metal alloy plating on the outer periphery and one plating treatment of aluminum coating. The plating or covering treatment for each steel wire 1 is intended to improve corrosion resistance.

In the first embodiment of the present invention, the aluminum wire rod 20 is configured such that a plurality of trapezoidal aluminum wire rods 2 having a predetermined thickness surround the steel core 10 in a cylindrical shape. In multiple layers.

At this time, the material of the trapezoidal aluminum wire rod (2) can be employed both of a material having reduced tensile strength by heat treatment and a material having high tensile strength without heat treatment. In order to reduce the tension sharing ratio in the aluminum wire rod, It is much more effective to employ aluminum wire.

2, the cross-sectional area of the aluminum wire rod 20 is greatly increased by making the shape of the aluminum wire rod 20 into a trapezoidal shape. By doing so, it is expected that the electric resistance loss is minimized.

Hereinafter, the steel wire which is a core of the present invention will be described in detail.

As described above, it is important to increase the tensile strength of the steel wire. This maximizes the tensile strength of the steel material formed of the steel wire, that is, maximizes the tension sharing ratio of the steel wire, thereby lowering the transition temperature. Section.

In the present invention, the core is an ultra-high strength plated steel wire adopted as a steel core of a working transmission line. First, the steel wire is composed of C 0.88 to 1.0%, Si 1.1 to 1.5%, Mn 0.3 to 0.7%, P 0.001 to 0.025% 0.025%, Cu 0.001-0.3%, Cr 0.2-0.95%, and the balance Fe and other unavoidable impurities. The wire rod of the super high strength steel wire is manufactured.

Then, after the surface treatment, the heat treatment, the drawing, the oil tempering and the zinc plating, the tensile strength is not less than 200 kgf / mm ² , the elongation is not less than 4.5% and the torsion is not less than 16 times Zinc-Aluminum-Mish Metal Alloy Plated Ultra-High Strength Steel Wire with Characteristics

A tensile strength range of the ultra high strength steel wire that can be used in the present invention is preferably about 180 to 250 kgf / mm ² , and one of zinc plating or zinc-aluminum-micro metal alloy plating and aluminum coating should be performed.

The above steel wire was twisted in seven strands in accordance with KS D7007 of Korea Industrial Standard to make a transmission wire core. A trapezoidal aluminum wire (1350-O tempering) having a tensile strength reduced to 6 to 7 kgf / mm ² was heat-treated with the ultra-high strength alloyed steel wire to form a 410 mm ² sample.

Here, the formation of the steel core excluding the alloy composition of the steel wire and the method of forming the aluminum wire material are well known in the art and will not be described in detail.

Table 1 shows a comparison of the tension sharing ratio with respect to the ACSR having the same cross-sectional area as that of the 410 mm ² transmission line employing the ultra-high strength alloy coated steel wire and the heat treated trapezoidal aluminum wire.

ACSR 410mm ² Tensile strength of steel wire
(kgf / mm ² ) Tensile strength of Al wire
(kgf / mm ² ) Aluminum wire rod
Area Load (kgf) Steel wire area load
(kgf) Al wire material tension ratio (%) Existing transmission line 130 16.2 6,697 8,755 43.3 Invention transmission line 200 7 2,893 13,470 17.6 250 7 2,893 16,837 14.6

As can be seen from Table 1, when the steel wire and the aluminum wire used in the existing transmission line are used, the tension sharing ratio of the aluminum wire material is 43.3%, but the ultra high strength steel wire (200, 250 kgf / mm ² ) And the heat-treated aluminum wire (7 kgf / mm ² ), the tension sharing ratio is greatly reduced by about 60 to 66% by 17.6% and 14.6%, respectively. This means that the transition temperature is reduced and the transmission capacity can be increased by the decrease.

≪ Embodiment 2 >

The working transmission line of the second embodiment of the present invention comprises a core 10 in which a plurality of steel wires 1 made of ultra-high strength plated steel wires are stranded; And an aluminum wire rod 30 surrounding the core 10 from the outside.

Each of the steel wires 1 should be galvanized or zinc-aluminum-micro metal alloy plating on the outer periphery and one plating treatment of aluminum coating. The plating or covering treatment for each steel wire 1 is for improving the corrosion resistance, which is the same as in the first embodiment.

In the second embodiment of the present invention, the aluminum wire rod 30 has a configuration in which a plurality of circular aluminum wire rods 3 having a predetermined thickness surround the steel core 10 in a cylindrical shape. Multiple layers are wrapped in layers.

The second embodiment of the present invention is different from the first embodiment in entirely the same as the first embodiment except that the aluminum wire rod is formed of a circular aluminum wire rod.

In the case of the machined transmission line formed according to the second embodiment of the present invention, only the sectional shape of the aluminum wire material is circular, which is different from that of the first embodiment, and the tension sharing ratio of the aluminum wire material is greatly reduced.

This means that the transition temperature is reduced and the transmission capacity can be increased by the decrease.

Claims (5)

Wherein each of the plurality of steel wires is stranded, and each of the steel wires is composed of C 0.88 to 1.0%, Si 1.1 to 1.5%, Mn 0.3 to 0.7%, P 0.001 to 0.025%, S 0.001 to 0.025%, Cu 0.001 to 0.3% 0.0 > 0. < / RTI > 0.95% of Cr and the balance of Fe;
And an aluminum wire wrapping the core. The super high strength steel wire is used as a machining power transmission line. The processed transmission line according to claim 1, wherein the plated steel wire is galvanized or zinc-aluminum-micro metal alloy plated or aluminum-coated steel wire. The machined transmission line according to claim 1, wherein the aluminum wire rod is a heat-treated aluminum wire. The machined transmission line according to any one of claims 1 to 3, wherein the aluminum wire rod is formed of a trapezoidal-shaped aluminum wire strand in a cross-section, and surrounds the steel core in multiple layers. The machined transmission line according to any one of claims 1 to 3, wherein the aluminum wire rod is formed of a circular aluminum wire strand in a cross section and surrounds the steel core in multiple layers.

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