JPS5873910A - Snow stack resistant wire - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] This invention provides an overhead power transmission system that prevents snow accumulation, 2.
In general, overhead power transmission lines built in areas with a large number of lightning faults are covered with snow that accumulates during lightning faults, and the amount of snow deposits is larger than 1 degree. L), heavy snow accumulates and falls under the wire along the outermost fine wire twist], and snow accretes on the outer metal body of the wire. In this way, when snow accretes on overhead power transmission lines, the weight of the wires increases considerably, resulting in the overhead power transmission lines sagging significantly and causing grounding accidents, resulting in an unbalanced static load across the spans. In addition to causing slope of the support, snow accretion OI! The tension of the electric wire will fluctuate abnormally due to the vibrations caused by the fall, which may cause serious accidents such as wire breakage, full contact, #1 circuit, etc., and further damage to ground structures due to fallen snow. 9) There is a risk of this happening.

Conventionally, for the purpose of preventing various accidents caused by snow accumulation as mentioned above, as a good power transmission line, the outer Kll metal wire of the stranded wire consisting of a large number of conductor elements allOIII was wound with scissors. A model that is suitable for wearing is proposed, h″′
According to Ch. Shikaji and So.'s 0-1 璽电纹, it was generated around *S by lightning current. Magnetic flux passes through the magnetic metal wire, causing it to generate heat (due to eddy current loss), and as a result, the surface ag of the wire rises, thereby preventing snow and ice from accreting on the wire.・ However, in this case, in the conventional technology, the knowledge that it is sufficient to simply wrap the magnetic metal wire around the electric wire is far beyond that, and it is possible to generate heat effectively and reliably. It is refreshing to see that even if the O technology described above is implemented in reality, it is not always possible to effectively prevent the formation of ice and snow, as no deep consideration was given to the conditions and crystallization of the metal material 011. In addition, due to the low reliability of wires, conventionally it was necessary to use a large amount of O magnetic gold R111 material to ensure a high calorific value, which had the disadvantage of unnecessarily increasing the weight of the wire. .

This invention was made in consideration of the above circumstances, and the purpose is to provide a new TK111 snow cover electric cable that does not increase the weight of the electric wire as much as possible and also promotes heat generation efficiently. It is.

The ζO invention OII example will be described in detail below with reference to *smr.

FIGS. 1 and 2 show a ninth embodiment in which the invention is applied to a steel core stranded wire, in which a plurality of steel cable wires l are tied together to form a steel core 2, On the outer surface of the steel core 10, a plurality of layers 4 are provided, which are made up of a large number of aluminum wires twisted together as conductor elements, and on the outside of the layer 4, A plurality of magnetic metal wires 5 having high magnetic permeability only in their own axial direction are arranged in a direction that intersects with the "twisting" direction of the conductor elements 4I3 constituting the outermost layer stranded wire, preferably at right angles or close to right angles to the twisting direction. The magnetic metal wire 5 may be made of only a magnetic material, but it may be made of a highly conductive material such as aluminum coated on its surface. It may be something.

Now, in the embodiments shown in FIGS. 1 and 2, during power transmission, magnetic flux is generated around each conductor element @ 3 constituting the am layer 4 due to the transmission current, and this type of wire usually does not carry alternating current. The magnetic flux changes from ゐ. Then, an eddy current is generated in the magnetic metal wire 5 outside the thin wire layer 4, which generates heat due to Joule heat. ], the axial direction of which intersects the twisting direction of the conductor strands 3 constituting the outermost layer strands, in other words, parallel to the direction of magnetic flux generated in each conductor element @3. Since the magnetic metal wire is wound in a direction close to , the magnetic flux density within the magnetic metal wire becomes extremely high, and the amount of heat generated becomes large.

Furthermore, if a magnetic material whose surface is coated with a highly conductive material, such as aluminum coated steel, is used as the magnetic metal wire 5, a secondary current is generated in the conductive coating layer to cancel the magnetic flux. Therefore, the temperature rise due to the secondary current is added, and the amount of heat generated becomes even larger due to the loss of heat.

Here, the magnetic metal wire 5 having a high electromagnetic coefficient only in its axial direction used in carrying out the present invention is a drawn 11H made by cold drawing of a magnetic material such as steel or alloy steel cape.
You can use t. The magnetic properties of the drawn wire rod obtained by the cold drawing process change directionally due to plastic deformation in the drawing direction, and the degree of alignment of the magnetic domains changes in the processing direction, that is, the axial direction of the wire rod, as compared to the waste pipe. While the magnetic permeability increases significantly in the cross-sectional direction, that is, in the direction perpendicular to one direction, the magnetic permeability decreases significantly. Therefore, a cold-drawn magnetic wire has a permeability in the axial direction that is higher than the permeability in the cross-sectional direction.For example, the present inventors et al. When we measured the magnetic permeability of aluminum coated steel with a wire drawing history, we found that the maximum relative magnetic permeability in the axial direction was 3 to 4, and 250 to 50011 at around AT/m.
1&, whereas the relative magnetic permeability in the cross-sectional direction is 3~sst, t when measured by arranging multiple aluminum-coated steel wires in parallel so that they touch each other. Even when the wires were similarly lined up and measured, the maximum relative magnetic permeability was at most 30a.

Further, although ordinary steel may be used as the magnetic metal wire, it is necessary to prevent the temperature of the wire from rising excessively in conditions other than the period of freezing and snowing, especially in the summer, beyond the original purpose of preventing freezing and snowing. In addition, it is preferable that the temperature of each cucumber is as low as 0°C, and that the material is made of only one material.
When the temperature near the installed electric wire drops to the point where it starts to form ice and snow, the magnetic metal wire S turns into a ferromagnetic material and increases the temperature of the electric wire, thereby preventing ice and snow from forming. At the same time, 1all of the electric wire temperatures under control when there is no ice and snow
temperature rise can be prevented.

In addition, when attaching the magnetic metal wire 5 to the electric wire, it may be formed into a spiral shape in advance and wrapped around the outer circumference of the electric wire.
Alternatively, the magnetic metal wire 5 may be wound in an open helical manner in the above embodiment, but it may be wound in a tightly wound spiral. Of course, the magnetic metal wire 5 may be one, or it may be two or more, and the magnetic metal wire 5 may have a round wire shape. However, it is not limited to this, and other tag-shaped objects may also be used.

As is clear from the above description, the snow-resistant electric wire of the present invention prevents ice and snow from forming by generating heat through eddy current loss. This method has the highest current density because it uses a material with high magnetic permeability only in The circumference of the outermost conductor wire? The permeability of the magnetic metal wire is extremely high in the direction of the magnetic flux generated or in a direction close to that direction, and the direction of the pre-electromotive flux and the direction of magnetic permeability are approximately the same, so the heat generation efficiency of the magnetic metal wire is It is possible to generate heat reliably and sufficiently, and as a result, the temperature of the wire can be sufficiently raised to effectively prevent the formation of ice and snow. Also, because of its excellent heat generation efficiency, magnetic The amount of metal wire used can be minimized, and the weight of the wire does not increase.

[Brief explanation of the drawing]

The drawings show an embodiment of the snow-resistant electric wire of the present invention, and FIG. 1 is a cross-sectional view thereof, and FIG. 2 is a side view thereof. In the figure, conductor material from three companies is shown, 4 is a conductor III wire layer, and 5 is a magnetic metal wire. Applicant Fujikura Electric Cable Co., Ltd. Representative Patent Attorney Yutaka 1) Hisashi Take (and 1 other person)

Claims (1)

[Claims] A magnetic metal wire having high magnetic permeability only in its own axial direction is placed around the outer periphery of a bare wire made by twisting conductor wires into multiple layers in a direction that intersects with the direction of the conductor wires constituting the outermost layer**. A snow cover electric wire characterized in that it is wrapped around.