JP2016110821A - Twisted wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a twisted wire capable of suppressing the generation of wind noise with a simple constitution.SOLUTION: Provided is a twisted wire to be overhead, having the outermost layer provided at the outermost side, and external element wires of the odd number in which the respective cross-sections are circular and respective diameters are mutually equal are twisted each other.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a stranded wire.

  Twisted wires having various cross-sectional shapes have been developed as transmission lines, distribution lines, overhead ground lines, branch lines, and the like that are suspended between steel towers (for example, Patent Documents 1 and 2).

  For example, Patent Document 1 discloses an aerial power transmission line configured by twisting a plurality of aluminum twisted wires obtained by twisting a plurality of aluminum wires around a steel core for the purpose of suppressing sag. Yes. Further, for example, Patent Literature 2 discloses an overhead electric wire in which the curvature radius of the upper surface of the cross section is increased and the curvature radius of the lower surface is decreased for the purpose of suppressing vibration.

JP 2001-43740 A JP-A-11-39950

  By the way, when wind is blown against the stranded wire, wind noise may be generated from the stranded wire. If the wind noise exceeds a certain level, complaints from residents living near the stranded wire may arise. The wind noise level depends on the cross-sectional shape of the stranded wire.

  An object of the present invention is to provide a stranded wire that can suppress the generation of wind noise with a simple configuration.

According to one aspect of the invention,
An imaginary stranded wire,
There is provided a stranded wire that is provided on the outermost side and has an outermost layer formed by twisting odd number of external strands each having a circular cross section and the same diameter.

  ADVANTAGE OF THE INVENTION According to this invention, the strand wire which can suppress that a wind noise generate | occur | produces by simple structure is provided.

It is sectional drawing orthogonal to the axial direction of the strand wire which concerns on one Embodiment of this invention. It is a side view of the stranded wire concerning one embodiment of the present invention. It is sectional drawing orthogonal to the axial direction of the strand wire which concerns on a comparative example. It is a side view of the twisted wire which concerns on a comparative example.

<One Embodiment of the Present Invention>
(1) Structure of stranded wire The stranded wire which concerns on one Embodiment of this invention is demonstrated using FIG. 1 and FIG. FIG. 1 is a cross-sectional view orthogonal to the axial direction of the stranded wire according to the present embodiment. FIG. 2 is a side view of the stranded wire according to the present embodiment.

  The stranded wire 10 of the present embodiment is configured to suppress the generation of wind noise by having a cross section perpendicular to the axial direction asymmetry with respect to the center when viewed from the axial direction. Details will be described below.

  In the following description, the “axial direction” of the stranded wire 10 refers to the longitudinal direction of the stranded wire 10, and the “radial direction” of the stranded wire 10 refers to a direction perpendicular to the axial direction of the stranded wire 10, that is, The transverse direction of the stranded wire 10 refers to the direction along the outer periphery of the stranded wire 10.

  The stranded wire 10 of the present embodiment is configured as, for example, a power line such as a transmission line or a distribution line that is aerial (built in the air), an overhead ground line, or a branch line. A transmission line is a line configured to transmit power between a power plant and a substation, and a distribution line is configured to distribute power from a substation (transformer) to each household. It is a line. An overhead ground wire is a wire configured to protect the power line from direct strikes caused by a lightning strike and to allow a current caused by a lightning strike to flow to the ground, and a branch line is a wire configured to support a steel tower or utility pole, etc. That is. When the stranded wire 10 is configured as a power transmission line or a distribution line, the stranded wire 10 is configured as, for example, a copper stranded wire or an aluminum stranded wire. Moreover, when the twisted wire 10 is comprised as an overhead ground wire or a branch line, the twisted wire 10 is comprised as an aluminum covered steel wire or a galvanized steel wire, for example.

  As shown in FIG. 1, a central strand 100 is provided at the center of the stranded wire 10. In the present embodiment, the number of central strands 100 is, for example, one.

  An outermost layer 400 is provided on the outermost side of the stranded wire 10 that is in direct contact with the wind so as to cover the outer periphery of the central strand 100. In the present embodiment, no strand layer is interposed between the outermost layer 400 and the central strand 100, and the inner side of the outermost layer 400 directly faces the central strand 100.

  The outermost layer 400 is configured by, for example, a plurality of external strands 300 twisted together. Each cross section of the external strand 300 is circular, and each diameter of the external strand 300 is equal to each other. The external strand 300 is made of the same material as the central strand 100.

  In the outermost layer 400, the number of external strands 300 is an odd number. In the present embodiment, the number of external strands 300 is, for example, five.

  As described above, since the odd number of external strands 300 are twisted in the outermost layer 400, the cross section perpendicular to the axial direction of the stranded wire 10 is not in relation to the center of the stranded wire 10 when viewed from the axial direction. It is point-symmetric. In other words, the cross section perpendicular to the axial direction of the stranded wire 10 is non-axisymmetric with respect to the central axis of the stranded wire 10. In the present embodiment, for example, in a cross section perpendicular to the axial direction of the stranded wire 10, a contact point where the two external strands 300 are in contact with each other is provided on the side opposite to the end portion where the one external strand 300 protrudes in the radial direction. As a result, the stranded wire 10 is recessed in the radial direction.

  As shown in FIG. 2, at any position in the axial direction of the stranded wire 10, the cross section perpendicular to the axial direction of the stranded wire 10 is asymmetric with respect to the center when viewed from the axial direction. Yes. For example, at point C between ABs of 1 pitch, the cross-sectional shape perpendicular to the axial direction of the stranded wire 10 is opposite to the cross-sectional shape of points A and B, and is the same as points A and B Furthermore, it is asymmetric with respect to the center when viewed from the axial direction.

  Further, as shown in FIG. 1, the outer strand 300 has a larger diameter than the central strand 100. Here, when the number of external strands 300 is N, the radius of the central strand 100 is d, and the radius of the external strand 300 is D, all the external strands 300 are connected to the outer periphery of the central strand 100. Assuming that all the outer strands 300 are in contact with each other in the circumferential direction, the ratio of the radius D of the outer strand 300 to the radius d of the central strand 100 can be obtained by using the cosine theorem. It is represented by (1).

As in this embodiment, when the number of external strands 300 is 5 (N = 5),
D / d = 1.426
It becomes. D / d is equal to the ratio of the diameter of the outer strand 300 to the diameter of the central strand 100.

  Actually, since the cross section of the external strand 300 in the direction perpendicular to the axial direction of the stranded wire 10 is elliptical due to the twisting rate at the time of twisting the external strand 300, the diameter D of the external strand 300 is It needs to be reduced. According to the trial calculation, assuming that the pitch in the axial direction when the external strands 300 are twisted is, for example, 10 times the layer core diameter (diameter passing through the center of each external strand 300 of the outermost layer 400), the central strand 100 The ratio of the diameter of the outer strand 300 to the diameter (= D / d) is reduced by about 4.8% from 1.426 to 1.360.

  Actually, the diameter of the outer strand 300 with respect to the diameter of the center strand 100 is considered in consideration of the tolerances of the diameters of the center strand 100 and the outer strand 300 and the twisting accuracy of the outer strand 300. The ratio (= D / d) is in the range of about ± 10% of the above value.

  That is, for example, the diameter of the outer strand 300 is 1.2 times or more and 1.6 times or less than the diameter of the center strand 100. If the diameter of the external strand 300 is less than 1.2 times the diameter of the central strand 100, the gap between the external strands 300 may increase and the wind pressure resistance of the stranded wire 10 may increase. On the other hand, when the diameter of the outer strand 300 is 1.2 times or more of the diameter of the central strand 100, the gap between the outer strands 300 can be made a predetermined distance or less. An increase in wind pressure resistance can be suppressed. On the other hand, if the diameter of the external strand 300 is more than 1.6 times the diameter of the central strand 100, the gap between the central strand 100 and the external strand 300 becomes large, and the stranded wire 10 is stabilized by a clamping clamp or the like. May be difficult to maintain. On the other hand, when the diameter of the external strand 300 is 1.6 times or less than the diameter of the central strand 100, the gap between the central strand 100 and the external strand 300 can be made a predetermined distance or less. Thus, the stranded wire 10 can be stably held by a clamping clamp or the like.

(2) Effects according to the present embodiment According to the present embodiment, the following one or more effects are achieved.

(A) According to this embodiment, the outermost layer 400 of the stranded wire 10 is configured by twisting an odd number of external strands 300 together. The cross section perpendicular to the axial direction of the stranded wire 10 is asymmetric with respect to the center when viewed from the axial direction. When wind is blown from a direction perpendicular to the axial direction of the stranded wire 10, a recess that is recessed in the radial direction is formed in at least one of the upper and lower ends of the stranded wire 10 in the direction perpendicular to the wind direction. The wind is disturbed and the generation of Karman vortices is suppressed. Thereby, it can suppress that a wind noise generate | occur | produces from the twisted wire 10. FIG.

For reference, FIG. 3 and FIG. 4 are used to compare this embodiment with a comparative example. FIG. 3 is a cross-sectional view orthogonal to the axial direction of the stranded wire according to the comparative example. FIG. 4 is a side view of a stranded wire according to a comparative example.
As shown in FIG. 3, in the comparative example, the outermost layer 940 of the stranded wire 90 is formed by twisting an even number of external strands 930 together. The cross section perpendicular to the axial direction of the stranded wire 90 is symmetric with respect to the center.
As shown in FIG. 4, in the comparative example, at any position in the axial direction of the stranded wire 90, the cross section perpendicular to the axial direction of the stranded wire 10 is symmetric with respect to the center. For example, at the Z point between XY of 1 pitch, the cross-sectional shape perpendicular to the axial direction of the stranded wire 90 is the opposite shape to the cross-sectional shape of the X point and the Y point, and is the same as the X point and the Y point. It is symmetrical with respect to the center.
For this reason, in the comparative example, when wind is blown from the direction perpendicular to the axial direction of the stranded wire 90, the upper end of the stranded wire 90 in the direction perpendicular to the wind direction is the lower end of the stranded wire 90 in the direction perpendicular to the wind direction. The shape is symmetric. For example, at portions where the external strands 930 project symmetrically at the upper and lower ends of the stranded wire 90 in the direction perpendicular to the wind direction, such as the X point, the Y point, and the Z point described above, the stranded wire in the direction perpendicular to the wind direction Both the upper and lower ends of 10 are arcuate. For this reason, the wind blown to the twisted wire 90 from the direction perpendicular to the axial direction forms Karman vortices at the separation point where the twisted wire 90 peels from the upper and lower ends. At this time, Karman vortices are alternately and evenly generated on the leeward side of the upper and lower ends of the stranded wire 90. And by producing regular pressure fluctuations around the stranded wire 90, wind noise of a specific frequency is likely to occur in the stranded wire 90 of the comparative example.

  On the other hand, according to this embodiment, when wind is blown from the direction perpendicular to the axial direction of the stranded wire 10, the upper end of the stranded wire 10 in the direction perpendicular to the wind direction is twisted in the direction perpendicular to the wind direction. The shape is asymmetric with respect to the lower end of the line 10. When wind is blown from the direction perpendicular to the axial direction of the stranded wire 10, the wind is disturbed by at least the radially concave side of the upper and lower ends of the asymmetrical, making it difficult to form Karman vortices, and pressure fluctuations It can be suppressed. And it is suppressed that regular pressure fluctuation arises around the twisted wire 10. Thereby, it can suppress that the wind sound of a specific frequency generate | occur | produces from the twisted wire 10. FIG.

(B) According to this embodiment, each cross section of the external strand 300 in the outermost layer 400 is circular, and each diameter of the external strand 300 is equal to each other. Thus, since the external strand 300 of the outermost layer 400 does not have a complicated shape, a plurality of external strands 300 can be easily manufactured using the same die. Therefore, it is possible to suppress the generation of wind noise from the stranded wire 10 with a simple configuration.

(C) According to the present embodiment, the number of external strands 300 of the outermost layer 400 is five. When the number of external strands is 7 or more, the cross-sectional shape of the stranded wire is not targeted, but the ratio of the irregularities on the surface of the stranded wire to the diameter of the stranded wire is small. For this reason, a wind may become difficult to be disturbed by the unevenness | corrugation of the surface of a strand wire. In addition, when the number of external strands is 7 or more, the diameter of the external strands becomes too thin, and therefore, the external strands are easily affected by trauma during construction or trauma caused by flying objects during use. Moreover, it becomes easy to receive the influence of the damage which arose at the time of attachment of a clamp etc., or the damage by the tool at the time of construction. Furthermore, if the diameter of the external strands becomes too thin, the strands are likely to melt when the strands are subjected to lightning strikes. On the other hand, since the number of the external strands 300 is 5, the ratio of the irregularities on the surface of the stranded wire 10 to the diameter of the stranded wire 10 can be increased, and the irregularities on the surface of the stranded wire 10 can reliably Can be disturbed. Moreover, the diameter of the external strand 300 does not become too thin, and the degree of influence of the above-described trauma can be reduced. Moreover, even if it is a case where the twisted wire 10 receives the lightning strike, the fusing of the twisted wire 10 can be suppressed. In particular, when the stranded wire 10 is configured as an aerial ground wire, the external strand 300 becomes thick, so that the lightning resistance of the stranded wire 10 as the aerial ground wire can be enhanced.

<Other Embodiments of the Present Invention>
As mentioned above, although embodiment and modification of this invention were described concretely, this invention is not limited to the above-mentioned embodiment and modification, and can be variously changed in the range which does not deviate from the summary.

  In the above-described embodiment, the case where the cross section perpendicular to the axial direction of the stranded wire 10 is asymmetric with respect to the center of the stranded wire 10 as viewed from the axial direction has been described. If the cross section perpendicular to the axis is astigmatic with respect to the center of the stranded wire when viewed from the axial direction, the cross section perpendicular to the axial direction of the stranded wire is mirror-symmetric with respect to the plane including the central axis of the stranded wire. The cross section perpendicular to the axial direction of the stranded wire may be rotationally symmetric with respect to the center of the stranded wire.

  In the above-described embodiment, the case where the outer strand 300 is made of the same material as that of the central strand 100 has been described. However, the stranded wire may have a steel core that functions as a tension member at the center. . For example, the center strand may be an aluminum covered steel wire, and the external strand 300 may be an aluminum wire.

  In the above-described embodiment, the case where there is one central strand 100 has been described. However, the central strand 100 may be configured by a plurality. That is, a plurality of strand layers may be provided inside the outermost layer.

10 Stranded wire 100 Center strand 300 External strand 400 Outermost layer

Claims (6)

An imaginary stranded wire,
A stranded wire having an outermost layer that is provided on the outermost side and is formed by twisting together odd-numbered external strands each having a circular cross section and the same diameter.   The stranded wire according to claim 1, wherein the cross section perpendicular to the axial direction is asymmetric with respect to the center when viewed from the axial direction.   The stranded wire according to claim 1 or 2, wherein the number of the external strands is five. It has a central strand provided in the center,
The twisted wire according to any one of claims 1 to 3, wherein a diameter of the external strand is larger than a diameter of the central strand.   The stranded wire according to claim 4, wherein a diameter of the external strand is 1.2 times or more and 1.6 times or less of a diameter of the central strand.   The stranded wire according to any one of claims 1 to 5, which is any one of a power transmission line, a distribution line, an overhead ground line, or a branch line.

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