JPH069127B2 - Difficult snow land type overhead ground wire - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a snow resistant overhead ground wire formed by twisting aluminum covered wires.

The so-called overhead ground wire is installed above the steel tower of the overhead power transmission line to prevent the transmission line from being damaged by lightning, but it has corrosion resistance to withstand many years of use and mechanical strength to withstand strong wind pressure under tension in the overhead wire over a long diameter. It is necessary to have a conductive property capable of coping with a large current at the time of a lightning strike or a flash, and in the past, mainly galvanized steel stranded wire was 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 recent progress of optical communication technology, as a communication line for communicating information control between facilities of a transmission line, as shown in FIG. 1, a pipe 9 having an optical fiber 6 accommodated therein is used. It has come into practical use as an optical fiber composite overhead ground wire in which aluminum covered wires 10, 10 ... Are twisted around the outer circumference. This is intended to be used for communication lines with an internal optical fiber while allowing the overhead ground wire to play the role of conventional lightning damage prevention, and as a communication means that makes use of the characteristics of an optical fiber with no radio interference or dielectric 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 the configuration so that the optical fiber 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 member 5 such as a sponge is arranged around it. The optical fiber 6 is loosely wound around its outer circumference, and then it is covered with a heat-resistant protective layer 7 such as glass cloth and a presser strap 8 thereof, which is housed in an aluminum pipe 9 and is surrounded by aluminum. It is formed by twisting the steel wires 10, 10 ...

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. The optical fiber 6 is designed so as not to be subjected to an unreasonable abnormal tension.

However, this is a story under normal weather conditions,
The story is different during heavy snowfall. That is, as is well known, snow is more likely to be attached to the electric wire than expected, and the self-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 is known that snow adheres to the wires because the snow accumulated on the top of the wires rotates around the wires under its own weight in order and grows in a tubular shape. It has also been found effective to form protrusions and 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 that is extended in the heavy snowfall area, and snow accretion is prevented. 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 aluminum wire 2 on the outer periphery of the steel wire 1 ′ by, for example, an extrusion method, but can be transformed into the fin-shaped projections 3 from the viewpoint of the outer diameter and strength of the overhead wire. Since the aluminum covering layer has a limited thickness, it is difficult to deform the fin-shaped protrusions 3 like fins, and the length H ₁ of the fin-shaped protrusions 3 is limited, so that a sufficient snow-diffusing effect is obtained. I can't hope.

If you try to lengthen the fin-shaped protrusions 3, the aluminum cover 2
Therefore, the diameter of the steel covered wire 10 becomes thicker, which inevitably increases the diameter of the entire overhead ground wire and increases its own weight, as well as the wind pressure. The load may increase and the safety margin may approach critical.

In view of such circumstances, the present invention intends to provide a snow landing type overhead ground wire which can easily form a fin-shaped projection and can obtain a marked snow landing effect. .

That is, the present invention provides a hard-to-snow type overhead ground wire having fin-shaped projections on the outer periphery of an overhead ground wire formed by twisting aluminum-covered wires. A steel core having a wire diameter smaller than that of other strands is provided inside, and fin-shaped projections of a desired length are efficiently formed along the one side surface of the fan-shaped cross section at the end thereof. Each fin-shaped protrusion of two adjacent strands having fin-shaped protrusions is arranged on the opposite side so that one fin-shaped protrusion can be formed by combining both strands. It is in.

Below, it demonstrates based on an Example. 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 the optical fiber composite overhead ground wire according to the present invention. As shown, the steel covered wire 10
Among the outer peripheral wires of the optical fiber composite overhead ground wire formed by twisting, the wires forming the fin-like projections 3 are naturally other wires so as to have a sufficient thickness to form the fin-like projections 3. It has a steel core 1b thinner than the steel core 1a. 2 is an aluminum cover.

As described above, since the steel core having a smaller diameter than the steel cores of other strands is used, when the aluminum sheath with a limited wall thickness of the aluminum sheathed wire is to be deformed, the fins can be deformed by a die or roll. The degree of freedom for forming the protrusions at the required height can be increased, and the height and shape are much more effective and easier than the case of ordinary aluminum steel wire to ensure snow adhesion. It is possible to form fin-shaped protrusions having

When thinning the steel wire of the strand forming the fin-shaped protrusion, by setting the strength of the steel wire to be greater than that of other strands, the tensile force of the steel wire of ordinary aluminum coated wire is increased. Strength is 1
By is a 80 kg / mm ² approximately, which 200 Kg / mm ² or more hopefully be sufficiently capable of holding standard tensile strength and thin wire diameter as 230 kg / mm ² or more, the outer diameter of the aluminum to be a steel wire Is kept almost equal to the conventional outer diameter, and the desired snow-diffusing effect can be obtained without lowering the standard breaking load of the aluminum steel wire itself.

Next, the fin-like projections 3 of the optical fiber composite overhead ground wire of the present embodiment are formed along one side surface of the aluminum-covered steel wire 10 having a fan-shaped cross section at its end. As shown in the figure, when the long fin-shaped projections 3 and 3 are formed on the opposite sides of the two adjacent strands 2 and 2 so as to combine the two, the thickness of the fin-shaped projections on the outer circumference of the overhead ground wire is reduced. There is an advantage that the fin-shaped projections are substantially broken because they are substantially increased.

As described above, in the snow-type overhead ground wire of the present invention, the strands forming the fin-like projections are made of a steel core having a smaller diameter than the steel cores of the other strands, and the fin-like projections are One fin is formed at the end of one side surface of the wire having a fan-shaped cross section, and the fin-like projections of two adjacent wire having such fin-like projections are arranged on the opposite sides to each other. Since it is formed like a fin-shaped projection, it is possible to exert a remarkable snow-diffusing effect incomparably when compared with the above-mentioned conventional example when it is extended.

As described above, according to the snow landing type overhead ground wire according to the present invention,
Since the fin-like projections can be formed extremely easily and the height and thickness of the fin-like projections can be freely selected as desired, the ground wire can contribute to the improvement of the performance of the overhead ground wire and further contribute to the difficulty of snow accretion. It is of great significance as a proposal that has obtained today's proclamation that snow damage is becoming a problem.

[Brief description of drawings]

FIG. 1 is a sectional view of an optical fiber composite aerial ground wire as an example of a conventional aerial ground wire, and FIG. 2 is a sectional view showing an embodiment of a snow-breaking aerial ground wire according to the present invention. 1, 1 ', 1a, 1b: Steel wire, 2: Aluminum covered wire, 3: Fin-shaped projection, 10: Aluminum 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 (56) References Actual Open 48-52078 (JP, U) Actual Open 57-106120 (JP, U) Actual Open 59-82210 (JP, U)

Claims (2)

[Claims] 1. A hard-to-snow snow-type overhead ground wire comprising an overhead ground wire formed by twisting aluminum-covered steel wires formed into a fan-shaped cross section, wherein fin-shaped projections are formed on a part of the twisted strands. , The inside of the strand forming the fin-like projections has a steel core having a wire diameter smaller than that of the other strands, and the fin-like projections of the strands are arranged along one side surface of the fan-shaped cross section. By arranging the fin-like protrusions of the two adjacent strands having such fin-like protrusions on the opposite sides, the two strands are joined together. A snow-type overhead ground wire which is constructed so as to form one fin-shaped projection. 2. The difficulty according to claim 1, wherein the aerial ground wire is an optical fiber composite aerial ground wire in which an optical fiber is housed in a pipe and an aluminum covered wire is twisted around the outer circumference of the pipe. Snow land type overhead ground line.