JPS5937530B2 - Difficult snow accretion power lines - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a snow-resistant electric wire that can prevent snow from accreting on the electric wire and causing it to swell.

When snow falls on electric wires, under certain climatic conditions, such as when the outside temperature is relatively high and the snow becomes moist, a film of water forms between the snow and the wires, making it difficult for the snow to fall. It is known that a cylinder of snow gradually grows around power lines, and its weight can lead to disconnections and collapse of steel towers.

This phenomenon of snow accumulation on the electric wires is due to the fact that the electric wires have a circular cross-sectional shape. That is, as shown in FIG. 2, snow α initially falls on the electric wire W as shown in FIG. 2A.

When the snow α accumulates beyond a certain level, the center of gravity shifts and it slides down around the electric wire while rotating in the direction of the arrow. When the first snow α begins to slide down due to its own weight, as shown in the figure,
Another layer of snow β accumulates above the electric wire w, and the snow α and β continue to rotate as shown in C in the figure, and a new layer of snow γ falls. Furthermore, it rotates as shown in Figure 2, and as this rotation continues, snow is constantly falling, and the cylindrical snow gradually grows in a concentric circle around the electric wire W, reaching several to ten times the outer diameter of the electric wire. This eventually leads to wire breaks and tower collapses. Therefore, it can be seen that in order to prevent snow from accumulating on the electric wires, it is sufficient to prevent the snow from rotating onto the electric wires.

This is because if the rotation is prevented, the snow will fall under its own weight. Based on this knowledge, a snow-resistant electric wire in which fin-like protrusions are formed on the outer periphery of the insulator of an insulated wire has been proposed, and a corresponding effect has been confirmed. Therefore, it is possible, and cannot be applied to bare wires. For this purpose, snow-resistant electric wires have been proposed in which wires are spirally wound around the outer circumference of bare wires or rings are fitted. Even so, it is necessary for a worker to attach it to the wire by riding in the air after the overhead wire has been installed (it is impossible to attach it before the overhead wire because the metal wheel must be passed through during the wire extension), which makes the work extremely complicated and difficult. It requires skill and is also highly dangerous. Furthermore, when attaching a separate member, there are problems with the weather resistance, aging, and corrosion of the material, and it often becomes necessary to replace it after a certain period of time.

The present invention has been made in view of these circumstances, and is superior in effect to finned wires by simply making the wire itself a special structure, and does not require any separate components. The purpose is to provide a snow-resistant electric wire, and its gist is that three strands of stranded wire with a circular cross section are arranged so that the center of each strand is at the vertex of a triangle in the cross-sectional arrangement. A snow-resistant electric wire that is twisted together so that the twisting direction is opposite to the twisting direction of each strand.

FIG. 1 is an explanatory partial perspective view showing an embodiment of a snow-resistant electric wire 10 according to the present invention, and shows a case where seven strands of stranded wire are used as the strands 1.

As shown in the figure, each strand 1 is twisted in a triangular arrangement such that its center is at each vertex of the triangle, and the directions of twisting of the snow-resistant electric wire 10 are respectively The direction in which the strands 1 are twisted is the opposite direction, that is, the direction in which the strands 1 are twisted is in the Z direction, whereas the direction in which the snow-resistant electric wire 10 is twisted is in the S direction. FIG. 3 shows how the snow behaves when snow falls on the electric wire 10 where snow is difficult to accumulate. In other words, as shown in FIG. 3, the electric wire 10 is difficult to snow, and the strands 1 are arranged in a triangular shape as if stacked with bales.
When snow falls on top of the snow, it initially becomes snow α7 as shown in Figure 3 A.
accretes. Naturally, when the amount of snow α5 increases, the snow α5 loses its balance and tries to rotate downward, but the hard-to-snow electric wire 10 has large twist grooves 2, and the snow α5 first loses its shape in these twist grooves 2. The mouth in figure 3 is snow α5 that has lost its shape.
This shows the fresh snow that has fallen since then.
The snow α'' and β7 try to continue rotating, but the snow-resistant electric wire 10 according to the present invention does not have a circular cross section like the electric wire w in FIG. 2, but has a triangular cross-sectional configuration with an acute angle. In addition, there is also a deep and large twisting groove 2, making it difficult for the snow to rotate easily as shown in Figure 2.Moreover, the twisting direction of the strands 1 and the twisting direction of the electric wire 10 are different from each other. Even if the snow tries to rotate along the twisting groove 2 of the electric wire 10, the twisted surface of the wire 1 forms unevenness in the direction almost perpendicular to the movement of the snow. The snow is also prevented from moving along the twisted grooves 2, and the snow is prevented from rotating in the circumferential direction of the electric wire 10 as well as in the longitudinal direction along the twisted grooves.

If the rotation is difficult, the initial snow α5 will eventually peel off and fall from the electric wire, as shown in Figure 3 (c), due to unbalance due to its own weight or due to the peeling conditions such as the voids existing between the twisted grooves 2. be.

In this way, even if the snow starts to rotate downward, it cannot stay in that position and falls one after another, so there is no danger of it rotating and growing as shown in Figure 2, which is a problem. This makes it possible to reliably demonstrate the snow accretion effect. If the wire 1 is a single wire, it will not be possible to prevent the snow from moving along the twisted grooves, and the effect of preventing snow from accreting will be considerably reduced.Also, even if the wire 1 is a stranded wire, the direction of the twist is If the direction is the same as the direction in which the electric wires 10 are twisted, there will be no irregularities formed in the direction substantially perpendicular to the movement of snow on the surface of the twisting groove that prevents the movement of snow, and the snow will not move along the twisting groove. Since the snow movement cannot be prevented, the effect of preventing snow accretion is considerably reduced compared to the case of the present invention.

As described above, in the snow-resistant electric wire according to the present invention, the basic arrangement of the strands is triangular, and the twisting direction of the strands and the twisting direction of the electric wire are reversed, thereby effectively preventing rotational movement of snow. death,
It eliminates the need for forming fins and adding separate members all at once, and it also achieves a snow-repellent effect that exceeds the effects of these methods, so its significance is truly great.

[Brief explanation of drawings]

FIG. 1 is an explanatory perspective view showing an embodiment according to the present invention, and FIG. 2 is an explanatory diagram showing the snow accretion behavior of a normal electric wire.
FIG. 3 is an explanatory diagram showing the behavior of snow on electric wires according to the present invention. 1: Bare wire, 10: Snow-resistant electric wire.

Claims (1)

[Claims] 1. Three wires with a circular cross section composed of stranded wires are arranged so that the center of each wire is at the vertex of the triangle in the cross-sectional arrangement,
A snow-resistant electric wire which is twisted together in such a way that the twisting direction is opposite to the twisting direction of each strand.