JPH0487512A - Joint of optical fiber composite submarine cable - Google Patents

Abstract

PURPOSE:To obtain a low loss joint having no concentration of external force by treating the marginal length with cables having same length as a group and arranging the treating parts on the opposite sides of the joint of large diameter power cable core. CONSTITUTION:Optical fiber units 8 are jointed, with same marginal length, on the outer circumferential side of the joint 12 of a power cable core 2 and classified into a plurality of groups, with the optical fiber units 8 having approximately same marginal lengths as same group, and at least one group of the optical fiber unit 8 is sagged at a position shifted in one axial direction from the power cable core joint 12. At least another group of the optical fiber unit 8 is sagged at a position shifted in the other axial direction from the power cable core joint 12. Furthermore, respective groups of the optical fiber units 8 are laid along the outer circumference of the power cable core 2 so that the sagging parts 14 are curved smoothly.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to the structure of a connecting portion of an optical fiber composite submarine cable in which a large number of optical fiber units are arranged and integrated around the outer periphery of a power cable core.

Conventional technology Cables such as power cables and optical cables have limited lengths due to manufacturing and transportation issues, so they must be unavoidably connected during installation, and connection points may also be provided for expansion and relocation. . A known connection structure for power cables is a structure in which conductors are connected and then insulated around their outer periphery, and for optical cables, permanent connections such as fusion splicing and connections using connectors are known. There is.

In the case of the latter optical cable connection, the connecting device has
In order to prepare for connection failure, and also for future connection changes, extra core wire length is required, and accordingly, it is necessary to process the extra connection length after connection. In general optical cables, the extra length of the connection can be handled by bending the excess fiber with a radius greater than the allowable bending radius and storing it in a tray, or by bending the excess fiber and storing it in a plastic sheet. has been adopted.

Problems to be Solved by the Invention Optical fiber composite submarine cables have a structure in which an optical fiber unit is arranged around the outer periphery of a power cable consisting of a conductor, an insulator, a jacket, etc., and an anti-corrosion layer or iron wire armor is provided on the outside. When connecting these, the conventional power cable connection structure can be used for the power cable core, and permanent connection methods such as fusion splicing can be used for the optical cable, but the processing of the excess length of the optical cable is conventional. It cannot be done using this method. That is, in the composite submarine cable, since it is necessary to provide an anti-corrosion layer and a protective layer such as iron wire armor on the outer layer, there is no room for providing the above-mentioned tray or plastic sheet.

Therefore, in optical fiber composite submarine cables, the excess optical cable connection length must be processed along the outer surface of the power cable core. However, optical cables cannot be bent to a radius smaller than the allowable bending radius in order to prevent an increase in loss. Many intersections will occur, and many intersections will occur in multiple layers. In particular, when the extra connection lengths are unequal, the route created when the extra lengths are smoothly curved with a radius greater than the allowable radius becomes complicated, so the number of intersections and the number of multi-layer intersections tend to increase. is remarkable. Since such intersections protrude outward relative to other locations, external loads tend to concentrate and act on them, and as a result, there is a risk of increased loss or damage due to crushing at that location. Ta.

This invention was made against the background of the above-mentioned circumstances, and it eliminates intersections in the extra length of the optical fiber connection when connecting an optical fiber composite submarine cable in which a large number of optical fiber units are arranged around the outer periphery of the power cable. The object of the present invention is to provide a connection structure that can reduce the number of connections.

Means for Solving the Problems In order to achieve the above object, the present invention provides a connection structure for an optical fiber composite submarine cable in which a plurality of optical fiber units are arranged around the outer periphery of the power cable core. Optical fiber units are connected with a predetermined extra length on the outer circumferential side of the connection part, and the optical fiber units are divided into a plurality of groups, each group having approximately the same extra length, and at least one group of optical fiber units is formed. is slackened at a position deviated from the power cable core connection portion in one axial direction, and at least one other group of optical fiber units is slackened at a position deviated from the power cable core connection portion in the other axial direction. Further, the optical fiber units in each group are arranged along the outer periphery of the power cable core so that the slack portions of the optical fiber units are smoothly curved.

Further, in the present invention, the optical fiber units are divided into three or more groups, each group having approximately the same extra length,
At least one group of optical fiber units is given slack at a position deviated from the power cable core connection part in one axial direction, and at a position deviated from the power cable core connection part in the other axial direction, the other optical fiber units are given slack. At least one group of optical fiber units is provided with slack, and the slack portions of the at least two optical fiber units are aligned along the outer periphery of the power cable core so as to curve smoothly while being offset from each other in the power axis direction. It is possible to have a configuration in which the

The connection structure of the present invention is a structure in which optical fiber units are connected to each other on the outer circumferential side of the connection part of the power cable core, and each optical fiber unit is connected with a predetermined extra length, so that slack does not occur. In addition, the power cable core connection part has a large diameter due to insulation treatment and lead sheathing. Optical fiber units are divided into multiple groups, each with approximately the same length, and the remaining length is processed for each group, and additionally, the remaining length is processed on both sides of the power cable core connection. Because you will be exposed,
In each group, there are almost no crossings between the optical fibers.

In addition, when processing the excess length of multiple groups on the same side in the axial direction relative to the power cable core connection part, the slack portions of the optical fiber units in each group are shifted from each other in the axial direction and curved smoothly. Since the optical fiber units are arranged along the outer periphery of the cable core, there is almost no crossing between the optical fiber units of each group.

Example Next, embodiments of the invention will be described with reference to the drawings.

FIG. 1 is a diagram schematically showing a connecting section according to the present invention, and the optical fiber composite submarine cables 1 connected to each other are configured as shown in cross section in FIG. 2, for example. That is, the power cable core 2 is constructed by sequentially providing an insulator 4, a jacket 5, and a reinforcing layer 6 on the outer periphery of a conductor 3 to the required thickness, and an anticorrosion layer 7 on the outer periphery of the reinforcing layer 6.
is formed. For these insulator 4, jacket 5, reinforcing layer 6, and anticorrosion layer 7, various conventionally known structures and materials can be adopted depending on power transmission capacity, installation depth, and the like. A plurality of optical fiber units 8 are spirally wound around the outer periphery of the anti-corrosion layer 7 at regular intervals, and flexible filaments such as polyethylene are inserted between these optical fiber units 8. Strings 9 are arranged, and accordingly, these polyethylene strings 9 are also wound helically around the outer periphery of the anticorrosion layer 7 in the same manner as the optical fiber unit 8. In addition, in order to prevent water running, it is also possible to fill tiny gaps between the optical fiber unit 8 and the polyethylene string 9 with sherry.

The optical fiber unit 8 and the polyethylene string 9 are fixed by a presser wrap 10 provided around the outer periphery thereof. Furthermore, an anti-corrosion layer 11 is formed on the outer periphery.

The power cable cores 2 are connected to each other by a normal connection means such as connecting a conductor 3, insulating the outer periphery, and applying lead coating to the outer periphery. The portion 12 has a larger diameter than the other portions.

On the other hand, each optical fiber unit 8 is connected with a necessary and sufficient extra length, and the extra connection length is stored at a location outside the power cable core connection section 12. That is, each optical fiber unit 8 is connected by, for example, fusing the core wires together and performing appropriate protection treatment on the outer periphery thereof. The connection work is performed through operations such as cutting, loading into the connector, and fusion, but the core wire is extremely thin and precision work is required to reduce loss at the fusion part. Therefore, it is not guaranteed that the connection will be successful after - number of operations. For this reason, the extra connection length is set to take into account the extra length for loading the connector and the extra length in case the connection operation fails and is restarted. Furthermore, the length to be removed each time a connection operation fails is determined.

Therefore, as schematically shown in Fig. 3, the extra connection length 13 that actually occurs after the completion of the connection work is defined as the maximum length when the connection is completed after - times of work, and the length 13 that actually occurs after the connection work is completed is calculated as follows: There are several types that are shorter by a certain size. To give a specific example, if a connection is made with an extra length of 500m, the longest extra connection length 13 will be lNO+m, and 100m will be removed from each optical fiber unit 8 for each failed connection. For example, if the second connection was successful, the remaining connection length would be 800m*, then the third connection would be 600mm, and the fourth connection would be 400m.
m. If the extra length is shorter than this, it would be difficult to connect in reality, so in the above example, the four types of extra length 1
3 will occur.

Optical fiber units 8 having different lengths of extra connection length 13 are
They are divided into a plurality of groups, with those having substantially the same extra connection length 13 being one group. In the above example, it is divided into four groups, and these are group A and group B in descending order of connection extra length 13.
4, the slack portion 14 of the optical fiber unit 8 of the A group and the D group is a location that is off to the left side of the power cable core connection portion 12 in the figure, as shown in FIG. The slack portions 14 of the optical fiber units 8 of groups B and 0 are provided at locations off to the right in the figure with respect to the power cable core connections 12.

Therefore, on the outer peripheral side of the power cable core connection part 14,
The optical fiber units 8 of each group are arranged along the outer surface of the power cable core connection section 12 and approximately parallel to each other, but at locations outside of this, only two of the optical fiber units 8 are originally arranged. The windings are arranged along the outer circumferential surface of the power cable core 2 on one side, and the other two optical fiber units 8 are loose, so their arrangement state is completely different. Therefore, for example, in the left side of the figure with respect to the power cable core connection portion 12, the slack portions 14 of the optical fiber units 8 of group A and the optical fiber units 8 of group D are shifted from each other in the axial direction of the cable 1. At the point where the optical fiber unit 8 of group A is given slack, the optical fiber units 8 of group B and group 0, which are given slack on the right side with respect to the power cable core connection part 12, are used as intervening Polyethylene string 9 and polyethylene string 15 for nuchal line
At the same time, the power cable core 2 is tightly wound around the outer circumferential surface of the power cable core 2 in the original manner. The state is shown in FIG. 5 as a partial sectional view.

Note that the polyethylene string 15 for the trowel and nuchal line refers to the slack portion 1
4, a dummy for the optical fiber unit 8 of the group that is missing (in the example of FIG. 5, the optical fiber unit of group A), and that has approximately the same outer diameter as the optical fiber unit 8, is used. It is cut to the required length and filled in a predetermined position.

This kind of winding is the same at locations corresponding to the slack portions 14 of the optical fiber units 8 of the other groups, and at locations corresponding to the slack portions 14 of the optical fiber units 8 of the D group, The optical fiber units 8 of group B and group 0 are tightly wound around the outer peripheral surface of the power cable core 2, and the slack portion 14 of the optical fiber unit 8 of group B is tightly wound.
At the locations corresponding to the optical fiber units 8 of groups A, 0, and D, the optical fibers 8 of groups A, 0, and D are tightly wound around the outer peripheral surface of the power cable core 2, and further, at locations corresponding to the slack portions 14 of the optical fiber units 8 of group D, Optical fiber units 8 of group A and group 0 are tightly wound around the outer peripheral surface of power cable core 2. The optical fiber unit 8 tightly wound around the outer circumferential surface of the power cable core 2 is pressed and wrapped with cotton tape 16 or the like at that part, and the optical fiber unit 8
The first layer is formed by

The slack portions 14 of the optical fiber units 8 in each group are smoothly curved with a radius greater than or equal to the allowable bending radius and are arranged along the outer circumferential surface of the first layer. In addition, this slack part 1
4 is EP with a hardness of about 60° on the outer peripheral surface of the first layer.
The optical fiber unit 8 is fixed and protected by providing a filler 17 such as rubber to a thickness that is approximately the same as the outer diameter of the optical fiber unit 8.

The above-mentioned surplus length portion is finally hidden by providing an appropriate protective layer around its outer periphery.

In the above embodiment, an example was explained in which the optical fiber units 8 are divided into four groups according to the length of the extra connection length 13, but in this invention, the point is that the optical fiber units 8 are divided into four groups according to the length of the extra connection length 13. may be divided into a plurality of groups, and may be divided into two parts, two parts, or a hill part or more.

As described in detail, in the structure of the present invention, cables of approximately equal length are grouped together to process the connection surplus length, and the process is carried out on both sides of the large-diameter power cable core connection. Therefore, not only will the optical fiber units of each group not cross each other, but also each group can have enough extra length processing space, so crossing with optical fiber units of other groups can be avoided. . Therefore, according to the connection structure of the present invention, there is no particular location where external force is concentrated, so a good connection with low loss can be obtained.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an embodiment of the present invention, Fig. 2 is a sectional view for explaining the configuration of an optical fiber composite submarine cable, and Figs. 3 and 4 show the processing process for extra connection length. The schematic diagram, FIG. 5, is a cross-sectional view of 7 parts in FIG. 1. DESCRIPTION OF SYMBOLS 1... Optical fiber composite submarine cable, 2... Power cable core, 8... Optical fiber unit, 12
...Power cable core connection part, 13...Connection extra length, 14...Sag part.

Claims (2)

[Claims] (1) In a connection structure for an optical fiber composite submarine cable in which a plurality of optical fiber units are arranged around the outer periphery of a power cable core, the optical fiber units are connected with a predetermined extra length on the outer periphery side of the connection part of the power cable core. At the same time, the optical fiber units are divided into a plurality of groups, each group having approximately the same extra length, and at least one of the optical fiber units is located at a position deviated from the power cable core connection part in one direction in the axial direction. and at least one other group of optical fiber units is provided with slack at a position deviated from the power cable connection portion in the other axial direction, and furthermore, the slack portion of the optical fiber units of each group is smoothed. A connection structure for an optical fiber composite submarine cable, characterized in that it is arranged along the outer periphery of a power cable core so as to be curved. (2) The optical fiber units are divided into three or more groups, each group having approximately the same extra length, and at least two groups of optical fibers are connected at a position deviated from the power cable core connection portion in one direction in the axial direction. A slack is provided to the unit, and at least one other group of optical fiber units is provided with slack at a position deviated from the power cable connection portion in the other axial direction, and the slack portion of the at least two groups of optical fiber units is provided. The optical fiber composite submarine cable according to claim 1, wherein the optical fiber composite submarine cables are arranged along the outer periphery of the power cable core so as to be curved smoothly while being shifted from each other in the axial direction of the power cable core. Connection structure.