JPH01157006A - Metal stranded wire combined with optical cable - Google Patents

Abstract

PURPOSE:To protect a metal stranded wire layer and optical cable from heat of arc by filling a gap between the metal stranded wire layer and a pipe containing an optical cable with a material to be fused and vaporized by heat of the arc. CONSTITUTION:A pipe 3 made of steel, aluminum alloy or the like, which contains an optical cable 2, is used for a core material. A stranded wire layer 5, which is formed by stranding plural metal element wires 4 made of aluminum, aluminum alloy, copper, copper alloy or the like, is formed outside the pipe 3, that is, core material. Inclusion is interposed in a gap between the stranded wire layer 5 and the pipe 3. The inclusion is made of such a material that is low in melting point and high in heat of fusion, heat of vaporization, heat of sublimation and heat of decomposition in comparison with the element wires 4. For example, such a metal as aluminum, bismuth, cadmium, lead or zinc, such an alloy as solder and such a synthetic resin as polyethylene are suitable for the inclusion. Receiving arc caused by the falling of the thunderbolt, the element wires 4 and the optical cable 2 are protected therefrom because heat of the arc is absorbed and extinguished into heat of fusion, heat of vaporization, heat of sublimation and heat of decomposition.

Description

[Detailed Description of the Invention] "Industrial Application Field" This invention relates to optical cable-containing metal stranded wires such as optical cable composite overhead ground wires and optical cable composite overhead power transmission lines, which are subject to arcing due to flash faults, lightning strikes, short circuits, etc. It has increased arc resistance to prevent damage to the metal.

``Prior art'' When an arc occurs near the suspension point of an overhead power transmission line or an overhead ground wire due to a lightning strike, etc., the metal wires that make up the metal strands may melt or break due to the heat of the arc. The metal strands may melt and cause a disconnection accident. Also,
In optical cable composite overhead ground wires, etc., which are composed of multiple optical cables, even the optical cables built inside the cable may be melted and damaged.

In order to prevent such problems, conventionally a so-called armor rod is wrapped around the surface of the stranded metal wire near the suspension point to protect the stranded metal wire from the arc.

``Problem to be solved by the invention'' However, this armor rod has a length of at most 2 m.
With such a length, it was difficult to completely protect the stranded metal wires and the internal optical cable.

Therefore, it is an object of the present invention to provide a metal combustible optical cable with excellent arc resistance that can reliably prevent the optical cable composite overhead ground wire from being melted or disconnected due to the heat of the arc. do.

"Means for Solving the Problems" This invention solves the above problems by filling the voids created between the stranded metal wire and the pipe containing the optical cable with inclusions made of a material that melts and vaporizes with arc heat. I tried to solve it.

``Operation'' Arc heat causes inclusions in the void to melt and vaporize before the metal wire, thereby consuming the arc heat and protecting the metal strands and optical cables from the arc heat.

"Example" Fig. 1 shows an example of a metal stranded wire containing an optical cable according to the present invention, and reference numeral 1 in the figure indicates an optical cable composite overhead ground wire (hereinafter referred to as ○P) as a metal stranded wire containing an optical cable according to the present invention.
It is abbreviated as GW. ).

This opcwl is made by twisting together a large number of metal wires 4 made of aluminum, aluminum alloy, copper, copper alloy, etc. on the outside of a core material of a pipe 3 made of steel, aluminum alloy, etc., which contains an optical cable 2. forming layer 5;
An inclusion 6 is interposed in the gap between the twisted wire layer 5 and the pipe 3.

The materials constituting this inclusion 6 include aluminum,
It has a lower melting point than the constituent materials of the wire 4, such as metals such as bismuth, cadmium, lead, and zinc, alloys such as solder, and synthetic resins such as FRP and polyethylene resin, and has a lower heat of fusion.
Materials with large heat of vaporization, sublimation, or thermal decomposition are used, especially phenolic resins reinforced with glass fiber or carbon fiber, which are known as ablation materials, or inorganic compounds that combine a large amount of crystal water, such as water. Polyethylene resin, polypropylene resin, etc. filled with a large amount of aluminum oxide or magnesium hydroxide are preferably used.

As a method for filling such inclusions 6, when the inclusions 4 are made of metals, alloys, etc., prepare strings of these metals or alloys, and when twisting each strand 4 around the pipe 3, simultaneously insert the If the inclusions 6 are made of FRP, a method of preparing a string-like prepreg in a semi-hardened state, interposing this prepreg during twisting, and heating and hardening it after forming the twisted wire may be adopted as appropriate. Ru.

When an 0PGWI filled with such inclusions 6 is installed as an overhead ground wire, even if it receives an arc due to a lightning strike, the heat of the arc will be directly absorbed by the strands 4 because they are good conductors of heat. is transmitted to the inclusion 6 between the lines, and the inclusion 6
Since the material constituting the wire has a lower melting point than the material constituting the strand 4, the inclusion 6 absorbs the arc heat first and begins to melt, and further vaporizes. Since the material constituting the inclusions 6 has a large heat of fusion, vaporization, sublimation, or thermal decomposition, most of the arc heat is spent on melting and vaporizing the inclusions 6. For this reason, each strand 4 and the optical cable 2 are protected from arc heat, and melting loss of the 0PGWI is therefore prevented.

In addition, if aluminum or FRP, which is easily deformed by pressure, is used for the inclusion 6, the above-mentioned protection effect from arc heat can be obtained, and the radius that is applied when the 0PGW 1 is constructed when passing through a fishing wheel or when crimped with a clamp. By the inclusion 6 absorbing the external force in the direction, the effect of preventing the pipe 3 from deforming can also be obtained.

Although the above embodiment relates to 0PGW, it goes without saying that a similar structure can be applied to an optical cable composite overhead power transmission line.

"Effects of the Invention" As explained above, the stranded metal wire containing an optical cable of the present invention has a pipe in the center of the stranded metal wire made by twisting a large number of metal wires, and the optical cable is built into this vibrator. At the same time, the gap between the metal strands and the pipe is filled with inclusions that melt and vaporize due to arc heat.
Even if this is subjected to an arc due to a short circuit, lightning strike, etc., the heat of the arc is consumed by melting and vaporizing the inclusions filled in the void, and the bare wire and optical cable are not affected by the thermal effects of the arc. Melting and disconnection of metal stranded wires and optical cables due to heat is prevented. Also,
If a material that is easily deformed by pressure is used for the inclusion, the external force acting in the radial direction of the stranded metal wire can be absorbed by the inclusion and dispersed in the circumferential direction, thereby preventing crushing accidents due to the external force of the optical cable. can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a stranded metal wire containing an optical cable according to the present invention. l...0PGW (metal stranded wire with optical cable),
2...Optical cable, 3...Pipe, 4...
... Metal wire, 5 ... Twisted wire layer, 6 ...
...Inclusions.

Claims (1)

[Claims] A pipe is provided in the center of the metal stranded wire, which is made by twisting a large number of metal strands, and an optical cable is built into this pipe, and the space between the metal strands and the pipe is melted and vaporized by arc heat. A stranded metal wire containing an optical cable, which is characterized by being filled with inclusions.