JPH0534643B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a method for suspending an electric wire, which makes it possible to branch or pull down the optical fiber of an optical fiber overhead electric wire at a suspended portion.

[Prior Art] When constructing a railway line by connecting overhead electric wires to a steel tower, a tension tower is used to hold the tension of the wires, and a suspension tower is used, which does not take part in the tension of the wires and simply suspends the wires. It is well known that The ratio of suspension towers to be placed between tension towers cannot be determined depending on the topography of the area, the size of the electric wires, etc., but in areas with good terrain, it may be expensive to increase the structural strength. In order to improve economic efficiency by minimizing the number of tension towers,
It is customary for 80 to 90% of all steel towers to be suspended steel towers. This also applies to optical fiber composite overhead wires, which are made by twisting optical fibers into overhead wires.

FIG. 4 is an explanatory diagram showing how the optical fiber overhead electric wire 2 is supported on the suspension tower 1 by the suspension clamp 3. As shown in the figure, in the suspension tower, the electric wire 2 is simply received by the suspension clamp 3 and suspended from the tower 1, and in such a suspension tower, the extra length of the electric wire can be taken and the optical fiber can be branched out. It has not been possible to branch optical fibers from such optical fiber composite electric wires or connect them by pulling them down, which has conventionally been done only in tension towers.

[Problems to be Solved by the Invention] The original purpose of the development of optical fiber composite overhead wires was to have optical fibers not receive electromagnetic induction, so they could be arranged in combination on power transmission lines or ground wires, and these power transmission lines or ground wires could be used as carriers. The reason is that they were trying to construct a communication line that would For this purpose, it is desirable that the optical fiber composite overhead wire itself be non-replicable and non-connective. However, recently, there has been a growing trend to use optical fibers installed on power transmission lines not only as communication lines, but also for the maintenance and management of the power transmission lines themselves. .

In other words, as UHV power transmission gets into full swing,
The management of steel towers under ultra-super high pressure has become more demanding, and it has become necessary to monitor each steel tower individually. As the power transmission voltage increases to 500,000 to 1,000,000 V, safety management requires careful consideration of the condition of the clamps at each tower, dirt on the insulators, snow accumulation, etc.
This is because it is essential to track down and confirm the location and condition of lightning strikes, the inclination of steel towers, and the fluctuations in the ground on which towers are built. In this case, various sensors will be installed on the steel tower, but if the maintenance management and control of these are performed using the optical fiber of the optical fiber composite overhead power line attached to the relevant power transmission line, it is possible to achieve both at once. This will be extremely convenient. This is why the concept of it as a mere communication line has been reconsidered.

However, as already explained, it is not possible to branch out the optical fibers at the suspension tower, and for this purpose, from the conventional technical concept, it is necessary to make all the towers tension-resistant, and the overhead line design must be adjusted accordingly. This is extremely unreasonable from both a top and economic standpoint. Therefore, there has been a strong demand for the development of a method for suspending optical fiber composite overhead wires that allows easy branching and extraction of optical fibers even from ordinary suspension towers.

[Means for Solving the Problems] The present invention has been made in view of the above circumstances, and its gist is to interpose an auxiliary wire at the position where the electric wire is to be supported by the suspension clamp, and to A light for gripping an electric wire by the end of the wire, fixedly supporting the auxiliary wire on a suspension clamp, and branching an optical fiber from an extra length of the electric wire inside the gripping member at the end of the auxiliary wire. This is in the method of suspending fiber overhead power lines.

[Example] The present invention will be explained below with reference to Examples.
FIG. 1 is an explanatory diagram showing a suspension section according to the present invention. 1 is a steel tower, 2 is an optical fiber composite overhead electric wire, and 3 is a suspension clamp, which is the same as in the case of FIG. 4. The difference from the case in FIG. 4 is that what the suspension clamp 3 directly supports is not the optical fiber composite overhead wire 2 itself as seen in the conventional example in FIG. 4, but the auxiliary wire 4. That is the point. The auxiliary wire 4 may be a separate wire of approximately the same size as the wire 2, or may be a separate steel wire, or in other words, it may be a flexible wire having the same strength as the wire 2. Bye. Reference numeral 5 denotes a gripping member which is connected to the end of the auxiliary wire 4 with a connecting portion 6 and is capable of gripping the electric wire 2, and a side view and a plan view of a specific example thereof are shown in FIGS. 2 and 3. The structure of the gripping member 5 may be a general bolt clamp or a compression type, as long as it can grip the electric wire effectively and does not damage the optical fiber inside. In FIG. 1, the total length of the electric wires 2 and auxiliary wires 4 on the outside of the gripping member 5 is configured to be the same as the total length of the electric wires 2 used for normal overhead wiring in FIG. 4. be done. In FIG. 1, 2' is the extra length of the electric wire 2. Regarding this extra length 2', if it is a newly installed electric wire, it is sufficient to take it in a loop shape from the beginning and then connect it to the overhead line, or if it is an existing electric wire, the excess length of the electric wire 2 caused by interposing the auxiliary wire 4 is sufficient. You can use the length. Here, the main feature of the present invention is that the extra length part 2' is fundamentally different from the shamper wire in the tensile part, and is a part of a single electric wire 2 that is suspended. . This makes it possible to satisfy the requirements for no relays or connections as a communication line.
Therefore, for example, in a newly installed electric wire, the extra length can be formed into a loop shape, and by leaving it as it is, the same light transmission as in the conventional example shown in FIG. 4 can be performed. After the installation, if it becomes necessary to attach a monitoring sensor to the tower 1 and connect it to the optical fiber in the electric wire 2 as described above, use the pre-formed loop-shaped extra length 2'. By using the optical fiber inside and connecting it to the sensor, a tower monitoring circuit can be easily realized. Also,
Even if the electric wire is an existing wire, the auxiliary wire 4 is separately attached to the existing suspension part as shown in FIG. It is sufficient to connect the optical fiber in the electric wire 2 to the sensor. That is, the present invention can be applied to both newly constructed lines and existing lines.

Furthermore, there are further advantages of adopting the configuration according to the present invention. In other words, if there is an unbalance in the overhead wire load between the spans on both sides of the suspension tower, the wires will slip to one side at the suspension clamp, and in the past, this would cause damage to the wires and internal optical fibers. There was a risk of giving. However, in the present invention, the optical fiber composite overhead wire is not directly held by the suspension clamp, but is held by the auxiliary wire, so there is no risk of damage to the wire itself. Furthermore, even if the slip occurs and the auxiliary wire is damaged by the suspension clamp, it is sufficient to simply replace the damaged auxiliary wire, and there is no need to replace the electric wire.

[Effects of the Invention] As described above, by applying the suspension method according to the present invention, it is not only possible to branch or lower optical fibers in a suspension tower, which was previously considered impossible, but also to The application of overhead optical fibers is not limited to conventional communication and control; it can be easily connected to sensors for monitoring each tower, so it can be directly applied to the maintenance and management of towers. It can greatly contribute to the safety management of power transmission lines, and even if slippage occurs at the suspended section, there is no risk of damaging the wires. should be highly evaluated.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing a suspension method according to the present invention,
2 and 3 are a side view and a plan view of the gripping member in FIG. 1, and FIG. 4 is an explanatory diagram showing a conventional suspension part. 1... Steel tower, 2... Optical fiber composite overhead wire,
2'... Extra length portion, 3... Suspension clamp, 4... Auxiliary wire, 5... Gripping member.

Claims (1)

[Scope of Claims] 1. An auxiliary wire is interposed at a position where the electric wire is to be supported by the suspension clamp, the electric wire is gripped by the end of the auxiliary wire, and the auxiliary wire is fixedly supported by the suspension clamp, and the auxiliary wire is fixedly supported by the suspension clamp. A method for suspending an optical fiber overhead electric wire so that the optical fiber can be branched from an extra length of the electric wire inside a gripping member at the end. 2. The suspension method according to claim 1, wherein the extra length of the electric wire is taken in in advance in a loop shape.