JP7056769B2 - Optical fiber composite overhead ground wire - Google Patents

Description

The present invention relates to an optical fiber composite overhead ground wire (hereinafter, abbreviated as OPGW) that is overheaded on a transmission line tower.

Conventionally, OPGW with an optical fiber cable mounted inside a lightning protection ground wire (overhead ground wire) installed to protect high-voltage power transmission lines from direct lightning has been installed at the top of the transmission line tower. .. This OPGW is resistant to disasters such as wind and flood damage, and is highly reliable as a transmission line for information and data on power security communication lines, so it is used for transmitting information and data on important lines such as transmission line system protection lines. ing.

FIG. 6A is a cross-sectional view of a conventionally known OPGW 100. As shown in FIG. 6A, the OPGW 100 has a tension member 103 (for example, a linear body made of fiber reinforced plastic) in an internal space 102 of a metal tube 101 (for example, an aluminum tube or a stainless steel tube). A plurality of optical fibers 104 are arranged in the center. Further, in the OPGW 100, a plurality of aluminum covered steel wires 105 are arranged on the outer peripheral side of the metal pipe 101.

FIG. 6B is a cross-sectional view of the optical fiber 104 constituting the OPGW 100. As shown in FIG. 6B, the optical fiber 104 is composed of a core 106, a clad 107 on the outside of the core 106, and a flexible resin coating 108 covering the core 106 and the clad 107. .. The core 106 and the clad 107 are made of quartz glass or plastic having a very high transmittance for light. Further, the flexible resin coating 108 is made of a flexible resin (for example, a silicone resin).

In the OPGW 100 as shown in FIG. 6, when the metal tube 101 has a crack caused by metal fatigue or the like, water (for example, rainwater) infiltrates into the inside of the metal tube 101 from the crack, and the infiltrated water penetrates into the inside of the metal tube 101. It may stay inside the metal tube 101 (particularly, inside the metal tube 101 in the hanging portion of the OPGW 100). When the water staying inside the metal tube 101 cools and freezes in winter, it expands inside the metal tube 101 and presses on the optical fiber 104, causing microbending loss in the optical fiber 104 and causing a communication failure. (Line outage, etc.) may occur. Further, in the OPGW 100 in which such a problem occurs, when the outside air temperature rises, the ice inside the metal tube 101 melts and the communication failure caused by the microbending loss is eliminated, so that the transmission line section in which the communication failure occurs (Specification of the transmission line section where the metal pipe 101 has a crack) is difficult, and it is difficult to take measures to prevent water from entering only in the cracked portion of the metal pipe 101.

The OPGW 200 shown in FIG. 7 is known as a technique for solving such a problem of the OPGW. In the OPGW 200 shown in FIG. 7, a sponge layer 202 is coated on the outer periphery of the optical fiber core wire 201, and the optical fiber core wire 201 is provided with a tension member 204 along the axis of the metal tube (aluminum pipe) 203. By twisting around the axis, the sponge layer 202 is filled tightly inside the metal pipe 203, and the sponge layer 202 prevents water from entering through the cracked portion of the metal pipe 203 (Patent Document). 1).

Japanese Unexamined Patent Publication No. 5-242740

However, the OPGW 200 shown in FIG. 7 has a problem that the work efficiency is deteriorated because the sponge layer 202 needs to be partially peeled off when the optical fiber core wires 201 are connected to each other. Further, in the OPGW 200 shown in FIG. 7, when a crack occurs in the metal tube 203, the sponge layer 202 deteriorates due to the influence of rainwater or ultraviolet rays infiltrating from the cracked portion of the metal tube 203, and the sponge layer 202 becomes the sponge layer 202. When cracking occurs, water infiltrates between the optical fiber core wire 201 and the metal tube 203, and when the water freezes, communication failure due to microbending loss occurs.

Therefore, the present invention provides an OPGW capable of preventing microbending loss of optical fibers without lowering the efficiency of connection work between optical fibers.

The present invention relates to an OPGW (optical fiber composite overhead ground wire) 1 in which an optical fiber unit 6 composed of a plurality of optical fibers 5 is housed inside an optical fiber protector 14 . In the present invention, the optical fiber protector 14 is arranged on a plurality of metal linear beam members 15 extending along the overhead wire direction at intervals along the overhead wire direction, and is provided on the linear beam member 15. It has a fixed metal ring-shaped member 16, and a plurality of gaps 17 that allow the passage of water are provided along the overhead wire direction. The gap 17 is a space formed between the plurality of linear beam members 15 and the adjacent ring-shaped members 16 and 16.

Since the OPGW according to the present invention is not designed to cover the outer periphery of the optical fiber with a sponge, it does not reduce the efficiency of the connection work between the optical fibers. Further, the OPGW according to the present invention can prevent ice from forming inside the optical fiber protector because rainwater falls through the gap of the optical fiber protector, or adheres to the inside of the optical fiber protector. Even if the water droplets freeze, the expanded ice can escape to the outside through the gaps of the optical fiber protector, and the microbending loss of the optical fiber caused by the ice can be prevented.

It is a figure which shows the OPGW which concerns on 1st Embodiment of this invention, FIG. 1 (a) is a sectional view of OPGW, FIG. Is an enlarged view of a part (part A) of the optical fiber protective body, and FIG. 1 (d) is an enlarged sectional view of the optical fiber. It is a figure which shows the OPGW which concerns on the 2nd Embodiment of this invention, FIG. 2A is a sectional view of OPGW, and FIG. 3A and 3B are cross-sectional views of the OPGW, FIG. 3B is a front view of an optical fiber protector constituting the OPGW, and FIG. 3C is a diagram showing an OPGW according to a third embodiment of the present invention. Is a side view of the optical fiber protector constituting the OPGW. It is sectional drawing of OPGW which concerns on 4th Embodiment of this invention. It is sectional drawing of OPGW which concerns on 5th Embodiment of this invention. It is a figure which shows OPGW which concerns on 1st conventional example, FIG. 6A is a sectional view of OPGW, and FIG. 6B is an enlarged sectional view of an optical fiber. It is sectional drawing of OPGW which concerns on 2nd conventional example.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[First Embodiment]
FIG. 1 is a diagram showing OPGW 1 according to the first embodiment of the present invention. 1 (a) is a cross-sectional view of OPGW 1, FIG. 1 (b) is a perspective view of a metal tube (optical fiber protector) 2 constituting OPGW 1, and FIG. 1 (c) is a perspective view of the metal tube 2. It is an enlarged view of a part (part A), and FIG. 1 (d) is an enlarged sectional view of an optical fiber 5.

As shown in FIG. 1, the OPGW 1 according to the present embodiment is formed of a tension member 4 (fiber reinforced plastic) at the center of an internal space 3 of a metal tube 2 (aluminum tube as an optical fiber protector, a stainless steel tube, etc.). A plurality of optical fibers 5 are arranged around the tension member 4. In this OPGW 1, the optical fiber unit 6 is composed of a plurality of optical fibers 5. Further, in the OPGW 1, a plurality of aluminum-covered steel wires 7 are arranged along the outer periphery of the metal pipe 2. Further, the OPGW 1 is provided with a space 8 between the inner surface 2a of the metal tube 2 and the outer surface 5a of the optical fiber 5.

The metal tube 2 of the OPGW 1 according to the present embodiment is a cylindrical body having a circular cross-sectional shape, and a plurality of holes (gap) 10 for water passage are formed along the circumferential direction and the longitudinal direction thereof. The water passage hole 10 that communicates the inside and outside of the metal pipe 2 is formed in a hexagonal shape. The plurality of hexagonal holes 10 are densely formed in a mesh shape, but the present invention is not limited to this, and the strength capable of protecting the optical fiber 5 housed therein is maintained, and the metal tube 2 has a plurality of holes 10. It may be formed at intervals so that the water that has entered the inside can be smoothly discharged. Further, in the present embodiment, the hole 10 of the metal tube 2 exemplifies a hexagonal hole, but the hole 10 is not limited to this, and may be a round hole, a polygonal hole (triangular hole, square hole, etc.). In such a metal pipe 2, when the OPGW 1 is overhead-wired to the transmission line tower, a plurality of holes 10 for water passage are arranged along the overhead wire direction.

The optical fiber 5 has a three-layer structure including a core 11, a clad 12 that covers the outer peripheral side of the core 11, and a flexible resin coating (silicone resin coating) 13 that covers the outer peripheral side of the clad 12. ..

Since the OPGW 1 according to the present embodiment does not cover the outer periphery of the optical fiber 5 with a sponge, it does not reduce the efficiency of the connection work between the optical fibers 5 and 5.

Further, in the OPGW 1 according to the present embodiment, since the water that has entered the inside of the metal pipe 2 is smoothly discharged from the plurality of holes 10 formed in the metal pipe 2, ice is not formed inside the metal pipe 2. As a result, the OPGW 1 according to the present embodiment does not cause the microbending loss of the optical fiber 5 caused by the ice inside the metal tube 2, and can prevent the occurrence of the communication failure due to the microbending loss.

Further, in the OPGW 1 according to the present embodiment, water droplets adhering to the inner surface 2a between the holes 10 and the holes 10 of the metal tube 2 and the outer surface 5a of the optical fiber 5 remain, and the water droplets freeze to generate ice. Even if the expanded ice can escape through the hole 10 for water passage, or can be accommodated in the space 8 between the inner surface 2a of the metal tube 2 and the outer surface 5a of the optical fiber 5, the optical fiber 5 is made of ice. It is not strongly pressed (no excessive external force acts), and microbending loss of the optical fiber 5 due to ice inside the metal tube 2 does not occur.

[Second Embodiment]
FIG. 2 is a diagram showing OPGW 1 according to the second embodiment of the present invention. 2 (a) is a cross-sectional view of OPGW 1, and FIG. 2 (b) is a perspective view of the optical fiber protective body 14 constituting OPGW 1. Further, since the OPGW1 according to the present embodiment shown in FIG. 2 has the same configuration as the OPGW1 according to the first embodiment except for the optical fiber protector 14, the OPGW1 according to the first embodiment is located at a position corresponding to the OPGW1 according to the first embodiment. The same reference numerals are given, and the description overlapping with the description of OPGW1 according to the first embodiment will be omitted.

As shown in FIG. 2, in the OPGW 1 according to the present embodiment, the optical fiber protective body 14 includes a plurality of metal linear beam members 15 extending along the overhead wire direction (direction of arrow C in FIG. 2B). , A plurality of metal ring-shaped members 16 arranged at intervals along the overhead wire direction and fixed to the linear beam member 15 (welded). In the optical fiber protective body 14, the three linear beam members 15 are in contact with the inner peripheral surface of the ring-shaped member 16, and the three linear beam members 15 are along the inner peripheral surface of the ring-shaped member 16. Three linear beam members 15 are arranged at equal intervals and are welded to the ring-shaped member 16. The ring-shaped members 16 are located so as to be orthogonal to the three linear beam members 15 arranged in parallel, and a plurality of ring-shaped members 16 are equidistantly spaced along the longitudinal direction of the linear beam members 15 (the overhead wire direction of OPGW 1). Have been placed. Then, in the optical fiber protective body 14, the space formed between the three linear beam members 15 and the adjacent ring-shaped members 16 and 16 becomes a gap 17 that allows water to pass through.

Since the OPGW 1 according to the present embodiment does not cover the outer periphery of the optical fiber 5 with a sponge, it does not reduce the efficiency of the connection work between the optical fibers 5 and 5.

Further, in the OPGW 1 according to the present embodiment, since the gap 17 of the optical fiber protector 14 allows water to pass through, ice is not formed inside the optical fiber protector 14. As a result, the OPGW 1 according to the present embodiment does not cause the microbending loss of the optical fiber 5 caused by the ice inside the optical fiber protector 14, and can prevent the occurrence of communication failure due to the microbending loss.

Further, in the OPGW 1 according to the present embodiment, even if water droplets adhering to the outer surface 5a of the optical fiber protector 14 or the optical fiber 5 remain and the water droplets freeze to generate ice, the expanded ice is gapped 17 Since it can be escaped by or absorbed in the space 8 between the optical fiber protector 14 and the outer surface 5a of the optical fiber 5, the optical fiber 5 is not strongly pressed by ice and is inside the optical fiber protector 14. There is no microbending loss of the optical fiber 5 due to the ice.

In the present embodiment, the optical fiber protective body 14 exemplifies a configuration in which three linear beam members 15 are arranged at equal intervals along the circumferential direction of the inner peripheral surface of the ring-shaped member 16, but the present invention is limited to this. Instead, two linear beam members 15 may be arranged along the circumferential direction of the inner peripheral surface of the ring-shaped member 16, and the linear beam member 15 may be arranged around the inner peripheral surface of the ring-shaped member 16. It may be configured to arrange four or more along the direction. Further, a plurality of linear beam members 15 may be arranged at unequal intervals along the circumferential direction of the inner peripheral surface of the ring-shaped member 16.

[Third Embodiment]
FIG. 3 is a diagram showing OPGW 1 according to the third embodiment of the present invention. 3A is a cross-sectional view of OPGW1, FIG. 3B is a front view of the optical fiber protecting body 18 constituting OPGW1, and FIG. 3C is a side view of the optical fiber protecting body 18 constituting OPGW1. Is. Further, the OPGW 1 according to the present embodiment shown in FIG. 3 has the same configuration as the OPGW 1 according to the first embodiment except for the optical fiber protector 18, so that the OPGW 1 according to the first embodiment corresponds to the OPGW 1 according to the first embodiment. The same reference numerals are given, and the description overlapping with the description of OPGW1 according to the first embodiment will be omitted.

As shown in FIG. 3, the OPGW 1 according to the present embodiment is a winding structure in which the optical fiber protective body 18 spirally winds (deforms) a metal rod-shaped member 20 at a constant pitch. The optical fiber protector 18 is a gap 21 in which the space between the adjacent windings 20a and 20a allows water to pass through. A plurality of gaps 21 are formed along the overhead wire direction of OPGW1 (direction of arrow C in FIG. 3C).

Since the OPGW 1 according to the present embodiment does not cover the outer periphery of the optical fiber 5 with a sponge, it does not reduce the efficiency of the connection work between the optical fibers 5 and 5.

Further, in the OPGW 1 according to the present embodiment, since the gap 21 of the optical fiber protector 18 allows water to pass through, ice is not formed inside the optical fiber protector 18. As a result, the OPGW 1 according to the present embodiment does not cause the microbending loss of the optical fiber 5 caused by the ice inside the optical fiber protector 18, and can prevent the occurrence of communication failure due to the microbending loss.

Further, in the OPGW 1 according to the present embodiment, even if water droplets adhering to the outer surface 5a of the optical fiber protector 18 or the optical fiber 5 remain and the water droplets freeze to generate ice, the expanded ice is wound. Since it can escape in the gap 21 between 20a and 20a or can be absorbed in the space 8 between the optical fiber protector 18 and the outer surface 5a of the optical fiber 5, the optical fiber 5 is not strongly pressed by ice and light is emitted. There is no microbending loss of the optical fiber 5 due to the ice inside the fiber protector 18.

[Fourth Embodiment]
FIG. 4 is a cross-sectional view of OPGW 1 according to the fourth embodiment of the present invention. The OPGW 1 according to the present embodiment shown in FIG. 4 has a structure in which the tension member 4 of the OPGW 1 according to the first embodiment is omitted, but other configurations are the same as those of the OPGW 1 according to the first embodiment.

The OPGW1 according to the present embodiment having such a configuration can obtain the same effect as the OPGW1 according to the first embodiment. The tension member 4 may be omitted from the OPGW 1 according to the second embodiment and the OPGW 1 according to the third embodiment as in the present embodiment.

[Fifth Embodiment]
FIG. 5 is a cross-sectional view of OPGW 1 according to the fifth embodiment of the present invention. The OPGW 1 according to the present embodiment shown in FIG. 5 has a configuration in which a spacer 22 is arranged in place of the tension member 4 of the OPGW 1 according to the first embodiment. A plurality of optical fiber accommodating recesses 23 are formed in the spacer 22 along the outer peripheral surface 22a, and the optical fiber 5 is accommodated in each optical fiber accommodating recess 23. The optical fiber accommodating recess 23 has an arcuate cross-sectional shape and is continuously formed in the longitudinal direction of the spacer 22 (the direction orthogonal to the paper surface of FIG. 5). The optical fiber accommodating recess 23 is preferably formed in a spiral shape along the outer peripheral surface 22a of the spacer 22 from the viewpoint of drainage.

The OPGW1 according to the present embodiment having such a configuration can obtain the same effect as the OPGW1 according to the first embodiment. In the OPGW 1 according to the second embodiment and the OPGW 1 according to the third embodiment, the spacer 22 may be arranged in place of the tension member 4 as in the present embodiment.

[Other embodiments]
In each of the above embodiments, the core 11 and the clad 12 of the optical fiber 5 are not limited to those made of glass such as quartz glass, and may be formed of plastic. Further, the optical fiber protective body may be a tubular body formed of a wire mesh (a tubular body having a structure in which a metal wire is woven into a mesh shape).

1 ... OPGW (optical fiber composite overhead ground wire), 5 ... optical fiber, 6 ... optical fiber unit, 14 ... optical fiber protector, 15 ... linear beam member, 16, ... ring-shaped member, 17 …… Gap

Claims (1)

In an optical fiber composite overhead ground wire in which an optical fiber unit composed of a plurality of optical fibers is housed inside an optical fiber protector.
The optical fiber protector is a plurality of metal linear beam members extending along the overhead wire direction, and a plurality of metal rings arranged at intervals along the overhead wire direction and fixed to the linear beam member. It has a shaped member and has multiple gaps along the overhead wire direction that allow water to pass through.
The gap is a space formed between the plurality of linear beam members and the adjacent ring-shaped members.
An optical fiber composite overhead ground wire characterized by this.

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