JPH0644825A - Difficult snow land type overhead ground wire - Google Patents

Abstract

(57) [Abstract] [Purpose] A desired fin-shaped protrusion can be easily formed by having a steel core with a wire diameter thinner than other strands inside the wire that forms the fin-shaped protrusion. (EN) Provided is a snow landing type overhead ground wire which is capable of exhibiting a significantly remarkable difficulty in snow landing. [Structure] Among the outer peripheral wires of an optical fiber composite overhead ground wire formed by twisting an aluminum steel wire 10, only the wires forming the fin-like projections 3 have a sufficient thickness to form the fin-like projections. As described above, the steel core 1b is thinner than the steel cores 1a of the other wires. As a result, it is possible to increase the degree of freedom for forming the fin-shaped projections at a required height by using a die or roll, and it is possible to exert a remarkable snow-diffusing effect.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a snow landing type overhead ground wire.

The so-called overhead ground wire is installed above the steel tower of the overhead power transmission line to protect the power transmission line from lightning damage.
It must have corrosion resistance to withstand many years of use, mechanical strength to withstand strong wind pressure under tension in overhead lines between long and long diameters, and electrical conductivity to handle large currents during lightning strikes and flashovers. Steel stranded wire has been used. After that, with the advent of the steel wire covered with aluminum, attention was paid to its mechanical strength, excellent conductivity and corrosion resistance, and this twisted wire with aluminum steel wire was gradually used as an overhead ground wire.

On the other hand, with the progress of optical communication technology in recent years, a pipe 9 having an optical fiber 6 housed therein as shown in FIG. 1 is used as a communication line for information control communication between facilities of a transmission line. Around the outer circumference of the steel covered wire 10, 10 ...
It has come to be used for the practical application of an optical fiber composite overhead ground wire made by twisting. This is intended to be used for communication lines with internal optical fibers while allowing overhead ground wires to play the role of conventional lightning damage prevention, and as a communication means that makes use of the characteristics of optical fibers with no radio interference or inductive interference. Attention has been paid.

In this case, the optical fiber is naturally low in mechanical strength, and the optical transmission characteristics are adversely affected by the strain. Therefore, due consideration is given to its structure so that it can withstand severe conditions. .

FIG. 1 is a cross-sectional view showing an example of such an optical fiber composite overhead ground wire, in which a high-strength core wire 4 such as a piano wire is arranged in the central portion, and a soft elastic material such as a sponge is arranged around it. The member 5 is provided, and the optical fiber 6 is loosely wound around the member 5 and then covered with a heat-resistant protective layer 7 such as a glass cloth and a presser strap 8 thereof, which is housed in an aluminum pipe 9 and its outer circumference is covered. Aluminum steel wire 10, 10 ...
... twisted together.

With this structure, even if tension is applied to the optical fiber 6, the high tension core wire 4 withstands the tension, and the tension applied to the optical fiber 6 is absorbed by the soft elastic member 5. Therefore, it is taken into consideration that an abnormal abnormal tension is not applied to the optical fiber 6.

However, this is a story under normal weather conditions, and the story is different during heavy snowfall. That is,
As is well known, snow is more likely to be attached to an electric wire than expected, and the weight of the electric wire is abnormally increased due to the snow accretion, which causes abnormal tension and stretches more than expected. In this case, the optical fiber cannot keep up with the elongation, causing not only disconnection and abnormal strain, but also the fatal ground wire itself may be disconnected.

It has been known that the snow adheres to the electric wire because the snow accumulated on the upper part of the electric wire sequentially rotates around the electric wire due to its own weight, and grows into a tubular shape. It is also known that it is effective to form a protrusion on the outer circumference of the snow to prevent the snow from rotating.

For this reason, the fin-shaped projections 3 as shown in FIG. 1 are formed on the overhead ground wire which is installed in the heavy snowfall area to prevent snow accretion. However, it is very difficult to actually form the fin-shaped projections 3 on the steel covered wire 10. That is, the aluminum steel wire 10 is formed by coating the outer circumference of the steel wire 1'with the aluminum wire 2 by, for example, an extrusion method, but the aluminum wire 10 can be transformed into the fin-like projections 3 in view of the outer diameter and strength of the overhead wire. Since the aluminum cover 2 has a limited thickness, it is difficult to project and deform the cover 2 like fins, and the length H ₁ of the fin-like protrusions 3 is limited, so that a sufficient snow-draining effect can be expected. There is no.

If the fin-like projections 3 are to be made long, the thickness of the aluminum sheath 2 must be increased, and the wire diameter of the aluminum steel sheathed wire 10 becomes thicker, which inevitably results in an aerial ground. Not only does the diameter of the entire wire become thicker and its own weight increases, but also the wind pressure load naturally increases, and the safety margin may approach the critical level.

The present invention has been conceived in view of the above situation.
It is intended to provide a snow-resistant type overhead ground wire which can easily form a desired fin-shaped projection and can exhibit remarkably remarkable difficulty in snow-falling.

[0012]

SUMMARY OF THE INVENTION That is, the present invention provides a snow-type overhead ground wire having fin-shaped projections on the outer circumference of an overhead ground wire formed by twisting aluminum covered wires, and The element wire forming the protrusion has a steel core having a wire diameter smaller than that of the other element wires inside so that the fin-like protrusion having a desired height can be efficiently formed.

[0013]

EXAMPLES Examples will be described below. In the description of the present embodiment, an optical fiber composite overhead ground wire will be described as an example, but it goes without saying that a normal overhead ground wire is also included.

FIG. 2 is a sectional view showing an embodiment of an optical fiber composite overhead ground wire according to the present invention. Aluminum steel wire 10
Among the outer peripheral strands of the optical fiber composite overhead ground wire formed by twisting, only the strands forming the fin-like protrusions 3 are fin-like protrusions 3.
The steel core 1b is thinner than the steel cores 1a of the other strands so that the steel core 1b has a sufficient thickness. 2 is an aluminum cover.

As described above, when the steel core having a smaller diameter than the steel cores of the other strands is used, the die or roll can be deformed when the aluminum sheath having a limited thickness is deformed. The degree of freedom for forming the fin-shaped protrusions to a required height can be increased by using the method, and it is much easier and more reliable than ordinary aluminum-coated steel wire, and is sufficiently effective for making it difficult to snow. Since fin-shaped protrusions having a height and a shape can be formed, it is possible to exert a remarkable snow-diffusing effect when compared with the above-mentioned conventional example when the fin-shaped protrusions are wired.

When thinning the steel wire of the strand forming the fin-like projections, the strength of the steel wire is made larger than that of other strands, so that the outer diameter of the aluminum steel wire is It is kept almost equal to the conventional standard outer diameter, and it is possible to obtain the desired snow adhering effect without lowering the standard breaking load of the aluminum steel wire itself.

[0017]

As described above, according to the aerial ground wire of the present invention, the fin-shaped projections can be formed very easily and the height and shape of the fin-shaped projections can be freely selected to a desired height and shape. It is possible to provide a ground wire that can contribute to the difficulty of snow accretion in addition to the performance improvement of the overhead ground wire, and the significance as a timely proposal today when snow damage is becoming a problem There is a big one.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an optical fiber composite overhead ground wire as an example of a conventional overhead ground wire.

FIG. 2 is a cross-sectional view showing an embodiment of a snow landing type overhead ground wire according to the present invention.

[Explanation of symbols]

 1, 1 ', 1a, 1b Steel wire 2 Aluminum covered 3 Fin-like projections 10 Aluminum steel covered wire

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hajime Hajime 1500 Kawajiri-cho, Hitachi City, Hitachi, Ibaraki Hitachi Cable Co., Ltd.Toyoura Factory (72) Inventor Mitsuo Onuki 1500 Kawajiri-cho, Hitachi City, Ibaraki Hitachi Cable Co., Ltd. Inside the Toyoura Plant (72) Inventor Tadashi Masaki 1,500 Kawajiri-cho, Hitachi City, Ibaraki Prefecture Hitachi Cable Co., Ltd.Toyoura Plant (72) Inventor Koyo Oshima 1500 Kawajiri-cho, Hitachi City, Ibaraki Hitachi Cable Co., Ltd.Toyoura Plant

Claims (3)

[Claims] 1. A snow-free overhead ground wire having a fin-like projection formed on a part of the twisted strand of an aerial ground wire formed by twisting aluminum steel wires, wherein the fin-like projection is A snow-type overhead ground wire which is characterized by having a steel core having a diameter smaller than that of other wires inside the wires to be formed. 2. The snow-ceiling type overhead ground wire according to claim 1, wherein the overhead ground wire is an optical fiber composite overhead ground wire in which an optical fiber is housed in a pipe, and an aluminum steel wire is twisted around the outer circumference of the pipe. Ground line. 3. The snow ground type overhead ground wire according to claim 1 or 2, wherein the twisted wires are compressed into a fan shape in cross section.