JPH0476441B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for fixing an optical cable wrapped around an overhead ground wire to the overhead ground wire near a steel tower.

[Prior art and its problems]

In recent years, lines in which optical cables are wrapped around and attached to existing overhead ground wires have been developed to perform optical communications using overhead power transmission lines. In such lines, in order to prevent the wrapped optical cable from loosening or moving, it is necessary to integrate the overhead ground wire and the optical cable at both ends of the span, that is, near the steel towers that support the overhead ground wire.

The conventional structure of this part is shown in FIG. 3, for example. That is, the overhead ground wire 11 is secured to the steel tower 13 via the retaining clamp 12, and the optical cable 14 is spirally wound around the overhead ground wire 11 and attached to the tower. The attached optical cable 14 is separated from the overhead ground wire 11 in the vicinity of the steel tower 13 and is drawn into a junction box or passed through the overhead ground wire on the opposite side. The optical cable 14 is separated from the overhead ground wire 11 at the location where the optical cable 14 is separated from the overhead ground wire 11.
A separation fitting 15 is provided to protect the bent portion from vibrations caused by wind. This separation fitting 15 is a guide for the optical cable 14, so to speak, and does not have the function of fixing the optical cable 14. The optical cable 14 is fixed to the overhead ground wire 11 in order to prevent the optical cable 14 from loosening or moving.
This is done by means of a fixed clamp 16. This fixing clamp 16 connects the overhead ground wire 11 and the optical cable 14.
The two are tightly tightened to integrate the two. It should be noted that a helical preform rod may be used instead of or in conjunction with the fixed clamp 16.

In any case, it has been found that the conventional fixing method involves tightening and fixing the optical cable and the overhead ground wire at the part where they are in contact with each other, which causes the following problems. In other words, the temperature of the overhead ground wire increases sharply in the event of a ground fault, and in that case, the optical cable also becomes hot due to the heat from the overhead ground wire, causing its protective coating to soften. When the protective coating becomes soft, the optical cable is deformed due to the clamping force applied by a fixing clamp or the like at the fixed portion of the optical cable, and lateral pressure is applied to the optical fiber core, causing problems such as increased transmission loss.

[Means for solving problems and their effects]

The present invention provides a method for fixing an attached optical cable that solves the problems of the prior art as described above. A method for fixing an optical cable to an overhead ground wire, the method comprising tightening and fixing the optical cable at a location where the optical cable is separated from the overhead ground wire using a tightening tool fixed to the overhead ground wire. .

At the point where the optical cable is separated from the overhead ground wire, even if the temperature of the overhead ground wire increases, the optical cable will not be heated to a high temperature, and therefore the optical cable will not soften, so the tightening force for fixing it will be reduced. Even if the signal is added, there is no risk of an increase in transmission loss.

〔Example〕

FIG. 1 shows an embodiment of the invention. In this embodiment, a fastening tool 17 for fixing the optical cable to the overhead ground wire 11 between the separation fitting 15 and the retaining clamp 12 is used.
is fixed, and the separation fitting 15 is fixed with this tightening tool 17.
The optical cable 14 led out from the cable is tightened and fixed. The optical cable 14 is tightened and fixed from above the rubber pipe 18, which is placed over the outer periphery of the optical cable 14. Since the rubber pipe 18 is elastic, there is no risk of damaging the optical cable 14 at the tightened and fixed portion, and since the rubber pipe 18 has a large coefficient of friction, it is highly effective in preventing movement of the optical cable 14.

In front of the separation fitting 15, a spiral preform rod 19 is wound around the outer periphery of the overhead ground wire 11 and the optical cable 14, but this preform rod 19 is intended to prevent the optical cable 14 from hanging. , has almost no tightening force.

FIG. 2 shows another embodiment of the invention. In this embodiment, a fastener 20 is integrally formed at the optical cable lead-out end of a separation fitting 15 fixed to an overhead ground wire 11, and the optical cable 14 is fastened and fixed by this fastener 20 via a rubber pipe 18. . The other configurations are the same as those of the above embodiment.

Although the above-mentioned embodiments have shown the method of fixing the optical cable at the location where the overhead ground wire is tied to the pylon, the present invention is equally applicable to the location where the overhead ground wire is pulled into the pylon. Further, although the optical cable was fixed via a rubber pipe, it is also possible to omit the rubber pipe.

〔Effect of the invention〕

As explained above, according to the present invention, since the optical cable is fixed at a location where the optical cable is separated from the overhead ground wire, the optical cable at the fixed portion is not heated to a high temperature due to the temperature rise of the overhead ground wire. Therefore, the optical cable does not become deformed even if a tightening force is applied for fixation, and there is an advantage that transmission loss does not increase.

[Brief explanation of the drawing]

FIGS. 1 and 2 are side views showing an embodiment of the method for fixing an optical fiber cable according to the present invention, and FIG. 3 is a side view showing a conventional method for fixing an optical fiber cable. 11 ~ Overhead ground wire, 12 ~ Retaining clamp, 13
~ Steel tower, 14 ~ Optical cable, 15 ~ Separation fitting, 1
7 - Tightening tool, 18 - Rubber pipe, 20 - Tightening tool.

Claims (1)

[Scope of Claims] 1. A method of fixing the optical cable to the overhead ground wire in the vicinity of a steel tower supporting the overhead ground wire around which the optical cable is attached, the method comprising: fixing the optical cable to the overhead ground wire at a point where the optical cable is separated from the overhead ground wire; A method for fixing an attached optical cable, characterized in that the optical cable is tightened and fixed using a tightening tool fixed to an overhead ground wire. 2. The fixing method according to claim 1, characterized in that a rubber pipe is interposed between the optical cable and a fastener that tightens and fixes the optical cable. 3. The fixing method according to claim 1 or 2, in which a fastener is integrally formed at the optical cable lead-out end of an optical cable separation fitting fixed to an overhead ground wire, and the fastener is used to secure the optical cable. Something that is characterized by being tightened and fixed.