JP2003043322A - Optical fiber cable and composite optical fiber wire for overhead earth optical fiber cable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical fiber cable having superior transmission characteristics, even if a swing or a rotation accompanying a vibration is caused, after the cable is installed and to provide a compound optical fiber wire for overhead earth optical fiber cable. SOLUTION: The optical fiber cable 4 is composed of at least one tape type coated optical fiber 11, housed in a spiral groove 6 formed on the peripheral face of a linear spacer 2, and the optical fiber cable is formed with the ratio P/D being 75 to 97, where P is the spiral pitch of the spiral groove 6 and D is the diameter of the layer core of the tape type coated optical fiber 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical fiber cable using a tape type optical fiber core wire and an optical fiber composite overhead ground wire using the optical fiber cable.

[0002]

2. Description of the Related Art A tape type optical fiber core made by collectively covering a plurality of optical fibers arranged in parallel, particularly a four-core tape type optical fiber core, is used for manufacturability and branching of each optical fiber after installation. Since it has good properties, it is often used as an optical fiber cable. As an optical fiber cable using a 4-core tape type optical fiber core wire, as shown in FIG. 2, an S-shaped or Z-shaped spiral groove (or a linear groove) formed on the peripheral surface of the linear spacer 22. An example is one in which at least one (three in FIG. 2) 4-core tape type optical fiber core wire 11 is housed in 26.

The four-core tape type optical fiber core wire 11 is less expensive than the silicon-coated optical fiber wire which is generally used for the optical fiber composite ground wire, and the optical fiber core wire 10 is Since it is also suitable for high density,
It is considered to be applied to an optical fiber composite overhead ground wire of a low voltage system route of 154 kV or less, which has a relatively mild temperature condition.

[0004]

However, since an optical fiber composite overhead ground wire is installed and laid on a transmission line tower with a large height difference, the load on the cable is higher than that of a general optical fiber cable. The external force applied is large. That is, when the optical fiber core wire 11 is applied to an optical fiber composite overhead ground wire and the overhead ground wire in the overhead wire state receives a strong wind, rolling accompanied by vibration occurs. Further, when the wind speed becomes 25 m / s or more, the vibration frequency increases, the vibration acceleration sharply increases, and the breath of the wind is added (the wind blows or stops). May change to.
Rolling or rotation accompanied by this vibration may cause the optical fiber core wires 11 to move in the longitudinal direction of the optical fiber to cause deviation, and as a result, the transmission loss of the optical fiber core wires 11 may increase.

In order to suppress the movement of the optical fiber core wire 11, it is generally effective to reduce the spiral pitch in the spiral groove 26 of the spacer 22 to increase the friction coefficient of the optical fiber core wire 11. it is conceivable that.

However, since the optical fiber core wire 11 is not circular in cross-section, when it is housed in the spiral groove 26 having the general shape (concave shape) shown in FIG. 2, the optical fiber core wire 11 is twisted and its A twisting back force, which is a reaction force against the twisting, is generated. If the spiral pitch is made smaller, the twist applied to the optical fiber core wire 11 becomes larger, and accordingly, the untwisting force also becomes larger. When this twisting back force becomes large, the stored state of the four-core tape type optical fiber core wire 11 in the spiral groove 26 tends to be disturbed. As a result, there is a problem that the transmission loss of the optical fiber core wire 11 increases.

An object of the present invention, which was devised in consideration of the above circumstances, is to use an optical fiber cable having good transmission characteristics even if rolling or swaying accompanied by vibration occurs after a wire is laid and used. An object is to provide an optical fiber composite overhead ground wire.

[0008]

In order to achieve the above object, an optical fiber cable according to the present invention has at least one tape type optical fiber core wire in a spiral groove formed on the peripheral surface of a linear spacer. In the optical fiber cable to be housed, the ratio P / D of the spiral pitch P of the spiral groove and the layer core diameter D of the tape type optical fiber core wire is set to 75 to 97.

According to the above construction, even if the optical fiber cable after the overhead wire / laying is rolled or rotated due to vibration, it is possible to prevent the tape type optical fiber core wire from moving in the longitudinal direction. it can. In addition, there is no possibility that the accommodation / arrangement state of the optical fiber core wires in the spiral groove will be disturbed.

On the other hand, in an optical fiber composite overhead ground wire using the optical fiber cable according to the present invention, the optical fiber cable according to the present invention is used as a core wire, and a plurality of ground wire strands are twisted around its outer circumference. It is a thing.

According to the above structure, even if the optical fiber composite overhead ground wire after the overhead wire / laying is subjected to vibrations such as rolling or rotation, the transmission characteristics are hardly deteriorated.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view of an optical fiber composite overhead ground wire using the optical fiber cable according to the first embodiment. Here, the same members as those in FIG. 2 are denoted by the same reference numerals.

Optical fiber cable 4 according to the present embodiment
Is at least one (three in FIG. 1) 4 in the spiral groove 6 formed on the peripheral surface of the linear spacer 2 shown in FIG.
Core tape type optical fiber core wire (tape type optical fiber core wire)
11 is housed and arranged, and the spiral pitch P of the spiral groove 6 and the layer core diameter D of the four-core tape type optical fiber core wire 11 are arranged.
The ratio P / D is set to 75 to 97. The layer core diameter D referred to here is formed by the center of the optical fiber element wire 10 of the four-core tape type optical fiber core wire 11 housed and arranged in the spiral groove 6 of the spacer 2. The diameter of the spiral is shown.

The number of the spiral grooves 3 formed on the peripheral surface of the spacer 2 may be one or plural (four are shown in FIG. 1). Further, the optical fiber unit in which the spacer 2 is covered with the protective tube 3 may be used as the optical fiber cable 4.

The material of the spacer 2 and the protective tube 3 is
The material is not particularly limited as long as it is lightweight and has sufficient strength, and examples thereof include Al and plastic.

The reason why the range of the ratio (P / D) between the spiral pitch P and the core diameter D is set to 75 to 97 will be described below.

If the P / D is less than 75, the twist applied to the four-core tape type optical fiber core wire 11 becomes large, and accordingly, the twisting back force also becomes large, and the overhead wire (laying).
Lateral vibrations and rotations accompanied by vibrations tend to cause disturbances in the storage / arrangement state of the optical fiber core wires 11 in the spiral groove 6. As a result, the transmission loss of the four-core tape type optical fiber core wire 11 is increased.

When the P / D exceeds 97, the four-core tape type optical fiber core wire is provided at both ends of the optical fiber composite overhead ground wire 1 due to rolling and rotation accompanied by vibration after the overhead wire (laying). This is because 11 is pulled in, that is, the four-core tape type optical fiber core wire 11 is moved in the line longitudinal direction. As a result, the transmission loss of the four-core tape type optical fiber core wire 11 is increased.

Next, in the optical fiber composite overhead ground wire 1 according to the present embodiment, the above-mentioned optical fiber cable 4 is used as a core wire, and a plurality of (eight in FIG. 1) ground wire elements are provided on the outer periphery thereof. The wire 5 is twisted together.

The ground wire 5 has high strength and
There is no particular limitation as long as it is a lightweight wire rod, and examples thereof include an Al-coated steel wire in which a core wire 13 made of a steel wire is covered with an aluminum layer 14.

Next, the operation of the optical fiber cable 4 of this embodiment and the optical fiber composite overhead ground wire 1 using the same will be described.

Optical fiber cable 4 according to the present embodiment
, The ratio P between the spiral pitch P of the spiral groove 6 in the spacer 2 and the layer core diameter D of the four-core tape type optical fiber core 11 is
By defining and optimizing / D, even if the optical fiber cable 4 after the overhead wire (laying) undergoes rolling or rotation accompanied by vibration, the optical fiber core wire 11 does not move in the longitudinal direction of the wire. (Movement can be substantially suppressed). Further, there is no possibility that the housed / arranged state of the optical fiber core wires 11 in the spiral groove 6 is disturbed. As a result, in the optical fiber cable 4, the signal transmission by the four-core tape type optical fiber core wire 11 can be performed stably and surely.

Further, this optical fiber cable 4 is shown in FIG.
When applied to the optical fiber composite overhead ground wire 1 shown in FIG. 1, even if the composite overhead ground wire 1 undergoes rolling or rotation accompanied by vibration, each optical fiber core wire 11 moves in the longitudinal direction of the wire and is not biased. There is no danger of it occurring. Further, there is no possibility that the housed / arranged state of the optical fiber core wires 11 in the spiral groove 6 is disturbed. As a result, even if the four-core tape type optical fiber core wire 11 is used, an optical fiber having good transmission characteristics (small transmission loss) substantially equivalent to an optical fiber composite overhead ground wire using a conventional silicon-coated optical fiber. The composite overhead wire 1 can be obtained.

Further, this optical fiber composite overhead ground wire 1
Is less expensive than the conventional optical fiber composite overhead ground wire, and the density of the optical fiber element wires 10 is high.

It is needless to say that the embodiments of the present invention are not limited to the above-mentioned embodiments, and various other embodiments are possible.

[0027]

In summary, according to the present invention, the following excellent effects are exhibited. (1) Even if the optical fiber cable using the tape-type optical fiber core wire after laying and laying is rolled or rotated with vibration, the tape-type optical fiber core wire may move in the longitudinal direction of the wire. In addition, there is no possibility that the accommodation / arrangement state of the optical fiber core wire in the spiral groove will be disturbed. (2) Even if the optical fiber composite overhead ground wire after the overhead wire / laying is subjected to vibrations such as rolling or rotation, the transmission characteristics are hardly deteriorated.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an optical fiber composite overhead ground wire using an optical fiber cable according to a first embodiment.

FIG. 2 is a sectional view of an optical fiber cable using a conventional four-core tape type optical fiber core wire.

[Explanation of symbols]

1 Optical fiber composite overhead ground wire 2 spacer 4 optical fiber cable 5 Ground wire 6 spiral groove 10 Optical fiber strand (tape type optical fiber core wire) 11 Tape type optical fiber core P spiral pitch D Optical fiber core layer diameter

Claims (3)

[Claims] 1. An optical fiber cable in which at least one tape-type optical fiber core wire is housed in a spiral groove formed on a peripheral surface of a linear spacer, wherein a spiral pitch P of the spiral groove and the tape are provided. The optical fiber cable is characterized in that the ratio P / D of the layer core diameter D of the optical fiber core is set to 75 to 97. 2. The optical fiber cable according to claim 1, wherein a plurality of the spiral grooves are formed on the peripheral surface of the spacer. 3. An optical fiber composite aerial system using an optical fiber cable, wherein the optical fiber cable according to claim 1 or 2 is used as a core wire, and a plurality of ground wires are twisted around the outer circumference of the core wire. Ground line.