WO2006129896A1

WO2006129896A1 - Overhead conductor utilizing c-type conductive wires

Info

Publication number: WO2006129896A1
Application number: PCT/KR2005/001886
Authority: WO
Inventors: Hyun-Ho Park; Sung-Yul Park; Sung-Uk Kim; Hee-Seok Yoon
Original assignee: Ls Cable Ltd.
Priority date: 2005-06-03
Filing date: 2005-06-17
Publication date: 2006-12-07
Also published as: KR20060126208A; KR100725290B1

Abstract

An overhead conductor in which aluminum strands are twisted around a reinforced steel is provided. In the overhead conductor, both sides of each aluminum strand have a concave portion and a convex portion, and each aluminum strand has a C-shaped section so that adjacent strands are contacted with each other.

Description

OVERHEAD CONDUCTOR UTILIZING C-TYPE CONDUCTIVE

WIRES

Technical Field

[1] The present invention relates to an overhead conductor, and more particularly to an overhead conductor utilizing C-type conductive wires that are stranded around a reinforced steel. Background Art

[2] Generally, an overhead conductor (or, an overhead transmission cable) such as an overhead power cable, an overhead earth wire and an OPGW (Optical Ground Wire) is installed by means of electric poles or power-transmission towers. In an installed overhead conductor, if there is a wind, a wind noise is generated to a side against the wind due to the Karman vortex. Various techniques have been developed to solve such a wind noise. These techniques are generally directed to changing a shape of a circular aluminum conductive wire used in the overhead transmission cable.

[3] Referring to FIG. 1 showing a sectional view of a conventional overhead transmission cable, conductive wires 3 having a trapezoidal shape are stranded around a reinforced steel 1. This overhead transmission cable 5 may increase a transmission capacity and a contact area between conductive wires by increasing the sectional area of the conductive wires even with the same cable outer diameter, thereby reducing a fatigue caused by vibrations.

[4] However, in case of the overhead transmission cable 5 utilizing trapezoidal conductive wires, adjacent trapezoidal conductive wires are not perfectly contacted, so stepped grooves are easily formed along outer layers of the conductive wires. In this case, a wind causes vibration, which accelerates stepping of the conductive wire surface. This phenomenon also causes corona effects or noise. In addition, in case strands of the overhead transmission cable are fractured, the strands may be protruded outward to release their stranded state, and also moisture may be penetrated between contact surfaces of the conductive wires to cause corrosion.

[5] Referring to FIG. 2 showing a sectional view of an overhead transmission cable according to another prior art, conductive wires 13 having Z- or S -shaped sections are stranded around a reinforced steel 11. If such Z-type conductive wires are utilized, a current capacity may be increased and a fatigue caused by vibrations may be reduced according to the increase of a sectional area of the conductive wires, in comparison to the case utilizing trapezoidal conductive wires. In addition, since there is no stepped portion between the conductive wires, corona effects or noise may be reduced, and also the Z-type strands may be relatively not easily released though the strands are fractured. [6] However, in case of the overhead transmission cable 15 utilizing Z-type conductive wires, the conductive wires have asymmetric shapes, so the conductive wires may not be regularly taken up around a reel, so the Z-type conductive wires should be prepared during the wire drawing process.

Disclosure of Invention

Technical Problem [7] The present invention is designed in consideration of the above problems, and therefore it is an object of the invention to provide an overhead conductor utilizing C- type conductive wires, which may increase a contact area between conductive wires, prevent penetration of moisture, prevent strands from being released, and uniformly take up conductive wires around a reel, by using the C-type conductive wires.

Technical Solution [8] In order to accomplish the above object, the present invention provides an overhead conductor in which aluminum strands are twisted around a reinforced steel, wherein both sides of each aluminum strand have a concave portion and a convex portion, and each aluminum strand has a C-shaped section so that adjacent strands are contacted with each other. [9] Preferably, a deviation between a radius of curvature of upper and lower surfaces of the aluminum strands and a distance from a cable center to upper and lower surfaces of a conductive wire is within ±10%. [10] Preferably, the concave portion and the convex portion corresponding to both sides of the aluminum strand have the same radius of curvature, which is in the range of

20% to 70% of a height of the aluminum strand.

Brief Description of the Drawings [11] FIG. 1 is a sectional view partially showing a conventional overhead transmission cable utilizing trapezoidal conductive wires; [12] FIG. 2 is a sectional view partially showing another conventional overhead transmission cable utilizing Z-type conductive wires; and [13] FIG. 3 is a sectional view showing an overhead transmission cable utilizing C-type conductive wires according to a preferred embodiment of the present invention.

Best Mode for Carrying Out the Invention [14] Hereinafter, an overhead conductor utilizing C-type conductive wires according to a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings. [15] FIG. 3 is a schematic sectional view showing an overhead conductor utilizing C- type conductive wires according to the preferred embodiment of the present invention.

[16] Referring to FIG. 3, a reinforced steel 30 having seven light reinforced wires stranded therein is prepared. The reinforced steel 30 is preferably configured such that seven reinforced steel strands cladded with aluminum are stranded into a predetermined shape. Here, the number of reinforced steel strands may be differently selected depending on capacity of the overhead conductor or the like. The cladding and stranding processes may be implemented as well known in the art.

[17] Subsequently, aluminum conductive wires to be stranded around the reinforced steel 30 are shaped into C-type conductive wires 40.

[18] The C-type conductive wires 40 are prepared in a manner of passing conductive wires through a form die or compression rollers. Upper and lower surfaces of the C- type conductive wire preferably have a radius of curvature identical to a distance from the center of cable to the surface of the conductive wire during the stranding process, and a deviation between the radius of curvature of the upper and lower surfaces of the C-type conductive wire and the distance between the cable center to the upper and lower surfaces of the conductive wire is preferably within ±10%. If the deviation between the radius of curvature and the distance is greater than ±10%, the stranded conductive layer may not be easily kept in a circular shape when the C-type conductive wires are stranded around the reinforced steel, which may cause release of the strands.

[19] Both sides of the C-type conductive wire 40 are classified into a convex portion and a concave portion, and the C-type conductive wire 40 is manufactured such that the convex portion and the concave portion are closely contacted. For this purpose, it is preferred that the convex portion and the concave portion keep their radii of curvature identically.

[20] In addition, the convex portion and the concave portion of the C-type conductive wire preferably have radii of curvature in the range of 20% to 70% of its height. If the radius of curvature is less than 20% of the height, it is difficult to strand and closely contact C-type conductive wires. If the radius of curvature is greater than 70%, there may arise problems of increasing a contact area between conductive wires or deteriorating prevention of moisture penetration.

[21] Then, when the C-type conductive wires are stranded around the reinforced steel, the concave portion is arranged to contact with a convex portion of an adjacent conductive wire. Industrial Applicability

[22] As described above, the overhead conductor utilizing C-type conductive wires according to the present invention has following advantages together with possessing all advantages of a conventional overhead conductor utilizing Z-type conductive wires. First, the conductive wires may be regularly taken up around a reel since they have symmetric sections. In addition, since C-type conductive wires may be manufactured not only in a wire drawing process but also in a stranding process, the work efficiency is enhanced. Moreover, since the C-type conductive wires are easily engaged and not easily separated during the stranding process, they may be arranged in an easy way.

Claims

[1] An overhead conductor in which aluminum strands are twisted around a reinforced steel, wherein both sides of each aluminum strand have a concave portion and a convex portion, and each aluminum strand has a C-shaped section so that adjacent strands are contacted with each other. [2] The overhead conductor according to claim 1, wherein a deviation between a radius of curvature of upper and lower surfaces of the aluminum strands and a distance from a cable center to upper and lower surfaces of a conductive wire is within ±10%. [3] The overhead conductor according to claim 1 or 2, wherein the concave portion and the convex portion corresponding to both sides of the aluminum strand have the same radius of curvature, which is in the range of 20% to 70% of a height of the aluminum strand.