JP2001014949A - Low wind noise, low wind pressure electric wire and low wind pressure electric wire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce increase on wind pressure load when oblique wind is accepted and to reduce weight load of a steel tower, by spirally winding a filament body on the outer periphery of an over head electric line at a specific winding angle to form a spiral projecting streak. SOLUTION: A winding angle of a filament body is 60 deg.±10 deg.. It has a characteristic that wind pressure load becomes largest, when it is exposed to wind from a 60 deg. direction. By winding a filament body with an S-twist in a spiral direction and a filament body with a Z-twist so that ratio of winding length in one diameter is 1:1 or 1:2, the occurrence of lift during strong wind is preferably suppressed. Partial strands of the outermost layer can be projected than the other strands to form a spiral projecting streak. The outermost layer of an electric wire 1 is structured by twisting segment strands 2, and a spiral streak 3 is wound on the outer periphery for reducing wind noise. Width and thickness of the spiral streak 3 are set in ranges that prevent extreme increase of wind pressure resistance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a low wind noise low wind piezoelectric wire and a low wind piezoelectric wire in which a wind pressure load in a specific wind direction is reduced.

[0002]

2. Description of the Related Art The load design of overhead power transmission lines is generally performed with a wind pressure load at a wind speed of 40 m / s, assuming a strong wind during a typhoon in summer. Since the wires used for overhead transmission lines are stranded wires and have irregularities on the surface, the wind pressure characteristics are slightly more complicated than when the surface is smooth like a cylinder.
If the outer diameter is 38.4 mm (ACSR 810 mm ² ) with a steel core aluminum stranded wire generally used for transmission lines up to 1000 kV, the wind speed
At around 16 m, the drag coefficient becomes minimum, and when the wind speed increases, the drag coefficient tends to increase (see FIG. 4). For this reason, the conventional transmission line has a relatively large wind pressure load at a wind speed of about 40 m / s, and the tower and its foundation need to be designed to have strength to withstand the wind pressure load. There was a problem.

In an area where wind noise of a transmission line is a problem, a spiral rod is wound around the transmission line to take measures against the wind noise (Japanese Patent Publication No. 53-14146).
Since the spiral rod has an outer diameter of 5 to 7 mm, when it is wound, the wind pressure load on the electric wire increases and the load on the steel tower increases. For this reason, depending on the strength of the electric wire and the tower, measures against wind noise may not be taken, which may cause a problem.

[0004] It is an object of the present invention to provide a low wind noise low wind piezoelectric wire and a low wind piezoelectric wire which can reduce the load on a steel tower.

[0005]

As a result of intensive studies, the present inventors have found that a power transmission tower generally has four pillars arranged at square corners. 90
Note that there is a characteristic that the wind pressure load becomes the largest when the wind is received from the 60 ° direction (when all the struts are hit by the wind) than when the wind is received from the ° direction and the 45 ° direction. did. Conventional low wind noise electric wires are wound with spiral rods regardless of the characteristics of such towers. It is possible to reduce.

Accordingly, the present invention relates to a low wind noise electric wire in which a wire is spirally wound around the outer circumference of an overhead electric wire to form a spiral ridge, and the winding angle θ of the wire is set to 60.
° ± 10 °. In this way, when receiving the oblique wind from the 60 ° direction, the increase in the wind pressure load due to the provision of the spiral ridge can be reduced, and the load on the steel tower can be reduced.

[0007] In the low wind noise low wind piezoelectric wire of the present invention, the spiral body has an S-twisted filament and a Z-twisted filament.
It is preferable that the winding is performed so that the ratio of the winding length in the span is 1: 1 to 1: 2 to suppress the generation of the lift in the strong wind.

The present invention also provides a low wind noise electric wire in which a part of the outermost wire is projected from another wire to form a helical ridge. Is wound in a spiral shape so that the wind noise is reduced, and the winding angle θ of the filament is set to 60 ° ± 10 °.

In the low wind piezoelectric wire of the present invention, the twist angle θ of the strand twisted on the outermost layer with respect to the longitudinal direction of the electric wire is provided.
Is set to 60 ° ± 10 °. With this configuration, the twist of the outermost strand is 60 ° ± 10 °.
Because it is oriented in the ° direction, even when the outermost layer is formed of strands having a circular cross section, the wind pressure load when receiving a diagonal wind from the 60 ° direction can be reduced.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings. [Embodiment 1] FIG. 1 shows an embodiment of the present invention. In the figure, reference numeral 1 denotes an electric wire whose outermost layer is formed by twisting the segment wires 2, and 3 denotes a spiral strip wound around the outer periphery of the electric wire 1 to reduce wind noise. Spiral strip 3
Is a rectangular aluminum wire, a galvanized steel wire, an aluminum-coated steel wire, or a wire made of a heat-resistant and weather-resistant polymer formed into a spiral shape. The width and thickness of the spiral strip 3 are set in a range where the wind pressure resistance does not increase significantly when the spiral strip 3 is wound around the electric wire 1. When the outer diameter of the electric wire 1 is 37.2 mm, the spiral strip 3 has a width of about 10 to 30 mm and a thickness of about 0.8 to 2.0 mm. In addition, the winding angle θ of the spiral strip 3 around the electric wire 1
(Angle with respect to the length direction of the electric wire 1) is set in a range of 60 ° ± 10 °, preferably 60 °.

The reason why the winding angle θ of the spiral strip 3 is set as described above is as follows. That is, as described above, the tower of the transmission line has the largest wind pressure load when it receives the oblique wind from the 60 ° direction, but when the spiral angle of the spiral strip 3 is set to around 60 °, the spiral strip 3 Since it is in the same direction as the oblique wind from the 60 ° direction, the wind pressure load on the spiral strips 3A and 3B becomes the smallest when receiving the oblique wind from the 60 ° direction. That is, when the wind pressure load on the tower is maximized, the wind pressure load on the electric wires including the spiral strips can be relatively small, so that the load burden on the tower can be reduced. The reason why the winding angle θ is set to 60 ° ± 10 ° is that in this range, a wind pressure load reduction effect substantially equal to that at 60 ° can be obtained. Incidentally, the winding angle of the spiral rod of the conventional low wind noise electric wire is about 15 ° to 20 °.

Although FIG. 1 shows a case where two spiral strips are wound, one spiral strip may be used.

[Embodiment 2] FIG. 2 shows another embodiment of the present invention. In this embodiment, a spiral rod 3S whose spiral direction is S twisted and a Z
The twisted spiral rod 3Z is wound so that the ratio of the winding length within one span becomes an appropriate ratio.
The winding length ratio of the S-twisted spiral rod 3S and the Z-twisted spiral rod 3Z is usually preferably 1: 1 in terms of workability and the like.
Wrap a 3S spiral rod 3S around 3/3
Around the Z-twisted spiral rod 3Z (or vice versa). The configuration of the electric wire 1 and the winding angles of the spiral rods 3S and 3Z are the same as in the first embodiment. When winding the spiral rod having the same spiral direction around the electric wire 1, there is a disadvantage that the lift when the strong wind is blown has a disadvantage.
There is an advantage that the lift can be reduced.

[Embodiment 3] FIG. 3 shows still another embodiment of the present invention. In this embodiment, as the electric wire 1, a part of the segment wire 2T of the outermost layer is replaced with another segment wire 2T.
A low wind noise electric wire having a helical ridge T with a height h formed so as to protrude further, and a spiral strip for wind noise reduction on the outer periphery of the electric wire 1 so that the helical direction is opposite to the ridge T. 3 is wound. The winding angle θ of the spiral strip 3 is 60 ° ± 10 °, which is the same as in the first embodiment. The width and thickness of the spiral strip 3 are the same as those in the first embodiment.

With this configuration, it is possible to obtain better aerodynamic characteristics than in the case of the second embodiment. The reason is that the twist pitch (winding angle) of the projecting ridges T formed by the thick segment strands 2T and the winding pitch (winding angle) of the spiral strips 3 are different, so that the lift is increased in a specific wind direction. A well-balanced aerodynamic characteristic that not only does not increase but also does not extremely increase the drag coefficient is obtained. Further, the winding of the spiral strip 3 can be performed at the time of manufacturing the electric wire, and the workability can be greatly improved.

FIG. 4 shows the results of testing the aerodynamic characteristics of the low wind noise low wind piezoelectric wire of FIG. Outer diameter of wire 1 is 3
The height h of the ridge T is 1 mm, and the thickness t of the spiral ridge 3 is 1 mm. For comparison, a conventional wire (ACSR810)
mm ² ) are also shown. Drag coefficient (Cd
x) is about 0.83 at a wind speed of 40 m / s, and the electric wire in FIG. 3 is about 20% lower in wind pressure than the conventional electric wire. The lift coefficient (CL) is about 0.1 at 15 m / s, but at other wind speeds it is almost the same as the conventional electric wire.

FIG. 5 shows the results of a test on how the drag / lift characteristics change with respect to the wind direction when the wind speed is 40 m / s for the low wind noise low wind piezoelectric wire shown in FIG. The solid line in the figure, the drag coefficient is estimated curve to be proportional to sin ² theta, in the conventional electric wire with no protrusions on the surface, but the drag coefficient is in good agreement with the estimated curve and wound spiral rib Figure It can be seen that the wire 3 deviates from the estimated curve.
At a wind direction angle of 60 °, the drag coefficient was almost the same as that of the conventional electric wire, and no increase in the drag coefficient due to winding the spiral strip was observed. On the other hand, the lift coefficient is
It is about 0.1, which indicates that it is stable.

[Embodiment 4] FIG. 6 shows still another embodiment of the present invention. In this embodiment, the wind pressure of the electric wire itself is reduced without considering the reduction of wind noise. That is, the low wind piezoelectric wire 4 has a twist angle θ of 60 ° ± 10 ° with respect to the longitudinal direction of the electric wire of the strand 5 having a circular cross section twisted on the outermost layer.

With such a configuration, the outermost element wire 5
Of the outermost layer of the wire 5
Even when is circular in cross section, the wind pressure load when receiving a diagonal wind from a 60 ° direction can be reduced.

[0020]

As described above, according to the present invention, the wind pressure load on the electric wire can be suppressed to a low level when the wind in the direction in which the wind pressure load on the tower is maximized is blown. can do. Therefore, it is possible to reduce the tower construction cost or implement measures against wind noise. The present invention can be expected to be effective even if it is not applied to the entire span, but is applied partially or intermittently.

[Brief description of the drawings]

1A and 1B show one embodiment of a low wind noise low wind piezoelectric wire according to the present invention, wherein FIG. 1A is a plan view and FIG.

FIGS. 2A and 2B show another embodiment of the low wind noise low wind piezoelectric wire according to the present invention, wherein FIG. 2A is a plan view and FIG.

3A and 3B show still another embodiment of the low wind noise low wind piezoelectric wire according to the present invention, wherein FIG. 3A is a plan view and FIG.

FIG. 4 is a graph showing drag / lift characteristics of the electric wire of FIG. 3;

FIG. 5 is a graph showing a change in drag / lift characteristics of the electric wire of FIG. 3 with respect to a wind direction angle.

6 (a) is a plan view and FIG. 6 (b) is a cross-sectional view showing one embodiment of a low wind piezoelectric wire according to the present invention.

[Explanation of symbols]

 1: Electric wire 2: Segment wire 2T: Thick segment wire 3: Spiral strip 3S, 3Z: Spiral rod 4: Low wind piezoelectric wire 5: Round wire

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tetsuya Okada 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Inside Furukawa Electric Co., Ltd. (72) Yoshikazu Kawaguchi 2-6-1 Marunouchi, Chiyoda-ku, Tokyo No. Furukawa Electric Co., Ltd. (72) Inventor Tamezo 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Furukawa Electric Co., Ltd. (72) Yukikatsu Aida 2-chome Marunouchi, Chiyoda-ku, Tokyo No. 1 F-term in Furukawa Electric Co., Ltd. (reference) 5G307 EA03 EA06 ED03 ED05 EE01 EF05 EF08

Claims (4)

[Claims] 1. A low wind noise electric wire in which a wire is spirally wound around an outer circumference of an overhead electric wire to form a spiral ridge, the winding angle θ of the wire is 60 ° ± 10 °. Low wind noise low wind piezoelectric wire characterized by the following. (2) The ratio of the winding length of the S-twisted filament to the Z-twisted filament within one span is 1: 1 to 1:
2. The low wind noise and low wind piezoelectric wire according to claim 1, wherein the wind is wound so as to form a lift of 2 when the wind is strong. 3. A low wind noise electric wire having a helical ridge formed by projecting a part of an outermost wire from another wire, wherein the helical direction is opposite to the ridge on the outer periphery. A low wind noise and low wind piezoelectric wire characterized in that a wind noise reducing wire is spirally wound so that the winding angle θ of the wire is 60 ° ± 10 °. 4. A low wind piezoelectric wire characterized in that the angle θ of the twist of the strand twisted to the outermost layer with respect to the longitudinal direction of the electric wire is 60 ° ± 10 °.