JPS59171407A - Method of accelerating snowfall resistance of aerial ground 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 The present invention relates to a method for more accurately increasing the anti-snow accretion effect of an overhead ground wire made of twisted aluminum steel wires.

So-called overhead ground wires are wires attached to the top of the towers of overhead power transmission lines to protect the power lines from snow damage, but they must have corrosion resistance that can withstand years of use, mechanical strength that can withstand strong wind pressure under long span tension, and lightning strikes. Galvanized steel stranded wires have traditionally been used because they must have conductive properties that can handle large currents during flashing and flashing. Later, with the appearance of aluminum-covered wires, attention was paid to their mechanical strength, excellent conductivity, and corrosion resistance, and these stranded aluminum-covered wires gradually came to be used instead for overhead ground wires. Ta.

On the other hand, with the recent progress in optical communication technology, as shown in FIG. Optical fiber composite overhead ground wires having aluminum coated wires 10.10-1 twisted around the outer periphery have come into practical use.

This is an attempt to use the internal optical fiber for communication lines while providing the overhead ground wire with the conventional role of lightning damage prevention. It is attracting attention.

In this case, the optical fiber naturally has low mechanical strength and distortion has an adverse effect on optical transmission characteristics, so some consideration is given to the structure of the fiber so that it can withstand even 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-tensile core wire 4, such as a piano wire, is arranged in the center, and a soft elastic member 5, such as a sponge, is arranged around it. The optical fiber 6 is loosely wound around its outer periphery, then covered with a heat-resistant protective layer 7 such as glass cloth and its presser string 8, and placed inside an aluminum pipe 9 and wrapped around its outer periphery. It is made by twisting aluminum covered wires 10.10-1--.

With this configuration, even if tension is applied to the optical fiber 6 portion, the high-tension core wire 4 will withstand the tension, and the tension applied to the optical fiber 6 will be absorbed by the soft elastic member 5. Care is taken to prevent excessive and abnormal tension from being applied to the optical fiber 6.

3- However, this is under normal weather conditions;
During heavy snowfall, it's a different story. In other words, as is well known, snow tends to adhere to electric wires more easily than expected, and the weight of the electric wires increases abnormally due to the accumulation of snow, which causes abnormal tension and elongation beyond normal conditions. In this case, the optical fiber will not be able to follow the elongation, and not only will breakage and abnormal distortion occur, but there is also the risk that the overhead ground wire itself will break, a fatal situation.

It is known that snow accumulates on electric wires because the snow that accumulates on the top of the wire rotates and falls around the wire due to its own weight and grows into a cylindrical shape.To prevent this snow from accumulating, It has also been found that it is effective to form protrusions on the outer periphery to prevent the snow from rotating.

For this reason, fin-like protrusions 3 as shown in FIG. 1 are formed on overhead ground wires connected to areas with heavy snowfall to prevent snow from accumulating. However, it is actually very difficult to form these fin-like protrusions 3 on the aluminum covered wire 10. That is, the aluminum coated wire 4-10 is made by coating the outer periphery of the steel wire 1- with an aluminum coat 2 by, for example, an extrusion method. The two deformable aluminum layers can only have a limited thickness, and it is difficult to deform them into fin-like protrusions, which limits the length Hl of the fin-like protrusions 3, making it difficult to achieve sufficient H snow accretion effects. I cannot hope for it.

If you try to make it longer with the fin-like protrusion 3, the aluminum cover 2
In doing so, the wire diameter of the aluminum covered wire 10 becomes thicker, which inevitably increases the diameter of the entire overhead ground wire, which not only increases its own weight but also naturally increases the wind pressure. There is a risk that the load will increase and the safety margin will approach criticality.

The present invention has been made in view of these circumstances, and provides a method of increasing the length of the fin-like protrusions to a sufficient extent without increasing the outer diameter of the overhead ground wire, thereby further improving the effect of preventing snow from accreting. This is what we are trying to provide.

The following is a sequential explanation based on examples.

FIG. 2 is a sectional view of an optical fiber composite overhead ground wire in which the method for improving snow accretion resistance according to the present invention is implemented.

In the present invention, the outer diameter of the aluminum-covered wire 10 is kept approximately equal to the conventional standard outer diameter, the strength of the steel wire 1 is actively increased, and the standard breaking load of the aluminum-covered wire itself (an aerial The wire diameter of the steel wire 1 can be reduced without reducing the tensile strength of the ground wire. In other words, the tensile strength of a normal aluminum coated wire is about 180/(g/-), but this is
/(y/i or more is preferably 230/1 g/- or more, so that the standard tensile strength can be sufficiently maintained even if the wire diameter is made thinner.Then, the second layer of aluminum is added to correspond to the thinner diameter of the steel wire 1. By increasing the thickness of the aluminum cover 2, the protruding length H2 of the fin-like protrusion 3 can be increased accordingly, and the effect of preventing snow from accreting can be further reliably and sufficiently improved. I can tighten it.

However, according to the present invention, difficulty in snow accretion is improved; however,
The outer diameter of the overhead ground wire itself is the same as the conventional standard outer diameter, and there is no risk that its own weight or wind pressure load will increase and adversely affect the safety factor.

In addition, in addition to increasing the strength of the steel wire, the steel wire 1a that does not form the fin-like projections 3 is drawn as thick as before, as shown in FIG. 3, and only the steel wire 1b that forms the fin-like projections 3 is drawn thickly. If it is made thinner, the entire overhead ground wire will maintain sufficient tensile strength even if the steel wire 1b is made thinner, so the aluminum sheath 2 on the outer periphery of the steel wire 1b can be made even thicker. This makes it possible to form the fin-like protrusions 3 even longer, and the detachment effect can be further enhanced.

Although the above explanation has been made using an optical fiber composite overhead ground wire as an example, it is clear that the technical idea of the present invention can also be applied to an overhead ground wire that has only conventional aluminum steel-covered wires without an internal optical fiber. Not even.

As described above, with the present invention, the wire diameter of the overhead ground wire can be maintained as before, without affecting its strength in any way.
It can significantly improve the effect of reducing snow accumulation, and the benefits to the industry are enormous.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an optical fiber composite overhead ground wire as an example of a conventional overhead ground wire, and FIGS. 2 and 3 (j) are sectional views of an overhead ground wire to which the method according to the present invention is applied. 1.1”, 1a, 1b: Steel wire, 2 aluminum coated, 3:
Fin-like protrusions, 10 Ni aluminum steel wire. Tomi tfB 2nd m 3rd prisoner D lbe t.

Claims (1)

[Scope of Claims] 1. The aluminum-covered wire of an overhead ground wire made by twisting aluminum-covered wires is tied to a substantially standard outer diameter, and the strength of the steel wire is actively increased to create an aluminum-covered ground wire. This is the reduction power of reducing the wire diameter of the steel wire without reducing the standard breaking load of the steel wire itself. Difficult @ snow formation improvement method for overhead ground wires in which the aluminum coating is deformed protrudingly to form longer fin-like protrusions on the outer periphery of the overhead ground wires. 2. The overhead ground wire accommodates the optical fiber in the pipe. The method for promoting snow accretion of an overhead ground wire according to claim 1, which is an optical fiber composite overhead ground wire in which aluminum steel wires are twisted around the outer periphery of the pipe.