JPH07320552A - Cable with external damage detection function and its detection system - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention relates to a cable structure having a function of detecting external damage caused by collision of flying objects with the cable, and a detection system thereof. [Claim 1] A cable having a cable core 1 in a central portion, an inner coating layer 6 around the cable core 6, and an outer jacket 5 around the cable core 1, wherein a plurality of optical fibers are housed between the inner coating layer 6 and the outer jacket 5. Arrange tubes 3 and 4 of a book of plastic or the like. An optical signal is made incident on this optical fiber, and a trauma state is detected from a change in the received optical signal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cable structure having a function of detecting external damage caused by a flying object colliding with a cable and a detection system thereof.

[0002]

2. Description of the Related Art A galvanized iron plate, a signboard, or the like is hit by a typhoon or a strong wind to collide with an aerial cable, which causes an accident. Conventionally, a cable structure with excellent impact resistance has been adopted as a countermeasure against these problems. For example, as shown in FIG. 3, there is a structure in which a flexible steel wire 2 is spirally wound around a cable core 1 having an inner coating layer 6 and a jacket 5 is provided around it. Wishhei 6-19404).

[0003]

When the cable having such a structure is used, it has an effect of protecting the cable body 1 against the impact force of the collision of flying objects. However, the protective jacket 4 may be damaged even if the cable body 1 is not actually damaged. As a result, there were cases where an unexpected secondary disaster occurred due to flooding, etc., or the damage expanded. Therefore, it is an object of the present invention to solve the above problems and provide a cable structure having a function of detecting external damage caused by a flying object colliding with a cable, and a detection system thereof.

[0004]

A cable having a damage detecting function according to the present invention is a cable having a cable core in a central portion, an inner coating layer around the cable core, and an outer jacket around the cable core. It is characterized in that a plurality of optical fibers for detecting the external damage of the cable are arranged between the outer cover and the outer cover at intervals.

Further, the cable is characterized in that a plurality of steel wires are provided alternately with the optical fibers.

Further, the cable is characterized in that the optical fibers are housed in a metal tube or a plastic tube, and the optical fiber-containing tubes are preferably arranged alternately.

The external damage detection system according to the present invention includes a cable core at the center, an inner coating layer around the core, and a plurality of optical fibers between the inner coating layer and the outer coating of a cable provided with the outer coating. A system comprising a cable in which fibers are arranged at intervals and an optical signal detection device, in which an optical signal is introduced from one end of the optical fiber and propagated, and the received optical signal is observed at a remote location. Specifically, it is to observe both or either of the method of observing reflected light at the same end and transmitted light at the other end.

[0008]

According to the above construction, the cable having the damage detecting function according to the present invention makes an optical signal incident on the optical fiber arranged between the cable core and the jacket and monitors it at a remote place. Thus, it is possible to detect an external damage caused by a flying object or the like. Further, by adjusting the type of the tube containing the optical fiber and the interval at which it is arranged, it is possible to detect the degree of injury at a remote location. Furthermore, the point of injury can be detected by measuring the time required for the pulse signal to enter the optical fiber and to be reflected and returned from the point of injury.

[0009]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols, without redundant description. FIG. 1 is a perspective view showing the structure of a cable according to an embodiment of the present invention.
Is a cable core, 2 is a steel wire, 3 is a plastic tube containing an optical fiber 3, 4 is a metal tube containing an optical fiber, 5
Is an outer coat, and 6 is an inner coating layer.

In FIG. 1A, a steel wire 2 and a plastic tube 3 accommodating an optical fiber are alternately arranged at a predetermined interval between a cable core 1 having an inner coating layer 6 and a jacket 5. It is a cable arranged in a spiral shape. The characteristic of this cable is that the wire connecting between the adjacent steel wires is arranged outside the tangent of the cable core 1 so that the steel wire 2 protects the cable core 1 even if a flying object collides, It is possible to avoid a situation where the person is directly disconnected. However, even at this time, the flying object damages the jacket 5, so that the plastic tube 3 accommodating the optical fiber is arranged between the steel wires 2 so that the condition of the damage can be detected.

FIG. 1B shows a cable in which a metal tube 4 containing an optical fiber is arranged between a cable core 1 having an inner coating layer 6 on the periphery and an outer jacket 5. Although the metal tube 4 is weaker in strength than the steel wire 2, it can be provided with the function of reinforcement and external damage detection by arranging the metal tube 4 at the same interval as the steel wire 2.

In FIG. 1C, a metal tube 4 containing an optical fiber and a plastic tube 3 are alternately arranged at a predetermined interval between a cable core 1 having an inner coating layer 6 and a jacket 5. It is a cable. The characteristics of this cable can be detected by being divided into three failure modes as shown in FIG. Mode 1 is a case where a failure is detected only in the plastic tube 3 containing one optical fiber, and the crack of the jacket 5 is shallow,
There is a room in the repair schedule. Mode 2: 1 plastic tube with optical fiber 3 and 1
This is the case where an obstacle is detected in the metal tube 4 containing the optical fiber of the book, and since the external damage penetrates the jacket 5, there is a risk that water will enter the cable. Mode 3: When three or more pipes are detected as faults, the damage from flying objects has reached the cable core 1,
Urgent recovery is needed. These modes can be detected in more detail by the type of tube or the intervals at which it is placed.

The above-mentioned optical fiber comprises a so-called glass or plastic doped with a dopant and a clad. The steel wire 2 protects the damage of the cable core caused by the impact of a flying object by arranging steel wires having a predetermined strength at predetermined intervals. The plastic tube 3 for accommodating the optical fiber has a main purpose of covering the optical fiber, and is formed of PE or PVC having flexibility and good workability. The metal tube 4 for accommodating the optical fiber is made of stainless steel or the like to protect the optical fiber and at the same time protect the cable core from being damaged by the impact of flying objects.
The inner coating layer 6 is formed by extrusion molding using PE, PVC, or the like, or is formed by winding a plastic tape, a non-woven fabric tape, or the like. Jacket 5 is cable core 1
For the purpose of protecting the metal tube and fixing the metal tube at a predetermined position at the same time, it is extruded by PE, PVC or the like.

An apparatus for detecting the above-mentioned external damage at a remote location is a light source for injecting an optical signal from one end of an optical fiber and a power meter for receiving the optical signal at the other end and measuring the level thereof. Further, as a device for detecting the position of the wound, it is a device for injecting a pulsed optical signal from one end of the optical fiber and measuring the time until the pulse signal is reflected and returned at the wound point.

[0015]

As described above, in the cable having the damage detecting function according to the present invention, an optical signal is made incident on the optical fiber arranged between the cable core and the jacket, and this is monitored at a remote place. As a result, it is possible to detect external damage caused by flying objects and the like. Further, by adjusting the type of the tube containing the optical fiber and the interval at which it is arranged, it is possible to detect the degree of injury at a remote location. Furthermore, the point of injury can be detected by measuring the time required for the pulse signal to enter the optical fiber and to be reflected and returned from the point of injury.

[Brief description of drawings]

FIG. 1 is a perspective view showing various cable configurations according to the present invention.

FIG. 2 is a diagram for explaining an effect according to the present invention.

FIG. 3 is a perspective view showing a conventional cable configuration.

[Explanation of symbols]

 1: Cable core 2: Steel wire 3: Plastic pipe 4: Metal pipe 5: Outer sheath 6: Inner coating layer

Claims (4)

[Claims] 1. A cable having a cable core in a central portion, an inner coating layer around the cable core, and an outer jacket around the inner core, wherein a plurality of cables are provided between the inner coating layer and the outer jacket for detecting a damage to the cable. A cable having a flaw detection function, characterized in that a plurality of optical fibers are arranged at intervals. 2. The cable having a wound detecting function according to claim 1, wherein the optical fiber is housed in a metal tube or a plastic tube. 3. A cable having a wound detection function according to claim 1, wherein a plurality of steel wires are provided alternately with the optical fibers. 4. A cable core is provided at a center portion, an inner coating layer is provided around the cable core, and an outer jacket is provided around the cable core, and a plurality of optical fibers are arranged at intervals between the inner coating layer and the outer jacket. A system comprising a cable and an optical signal detection device,
A cable damage detection system characterized by introducing an optical signal into one end of an optical fiber to propagate it and observing the received optical signal at a remote location.