JPS62249027A - Measuring method for tension of electric wire - Google Patents

Abstract

PURPOSE:To measure a tension applied to an electric wire without being influenced by a voltage of the electric wire and a magnetic field, by measuring an optical transmission loss of an optical fiber core wire which has generated a micro-bending loss, which has been contained in the electric wire. CONSTITUTION:An optical fiber core wire 3 which has generated a micro- bending loss in advance is contained in an overhead ground wire 2 which has been erected between steel towers 1A, 1B. Also, one end of this optical fiber core wire 3 is connected to a light source 5 through a lead use non-metal optical cable 4, and the other end is connected to an optical power meter 7 through a lead use non-metal optical cable 6. In this state, when a relation of a tension of the overhead ground wire 3 and an optical loss of the optical fiber core wire 3 is derived in advance by an experiment, the tension of the overhead ground wire 2 can be measured by measuring the optical loss of the optical fiber core wire 3 based on a variation of the tension of the overhead ground wire 2 by the optical power meter 7.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field] The present invention relates to a method for measuring tension applied to an electric wire that has been installed or is being installed.

[Prior art and its problems]

Conventionally, a common method for checking whether abnormal tension is applied to electric wires is to connect a tension meter to a bundle of wire ends and measure the tension using the tension meter.

However, tension meters generally measure strain caused by tension by converting it into an electrical signal, so if voltage is applied to the wire, the wire and tension meter must be insulated, and the insulation must be It has the disadvantage of being a big deal. There is also the problem that a tension meter cannot be connected to electric wires that are being erected.

[Means for solving problems and their effects]

In view of the problems of the prior art as described above, the present invention provides a wire tension measurement method that does not require a normal tension meter. The present invention is characterized in that the tension applied to the electric wire is measured by storing the optical fiber in the electric wire and measuring the optical transmission loss of the optical fiber core wire.

Microbending loss is an optical loss that occurs when the axis of an optical fiber bends on the order of microns (μm).
It is known that this phenomenon occurs when an optical fiber is improperly coated with a positive coating or subjected to large temperature changes after coating. Normally, various measures are taken to reduce this microbending loss as much as possible, but the present invention improves this in one way! It is intended to be actively used for measuring wire tension.

Microbending loss is caused by small bends in the optical fiber, so when tension is applied to the optical fiber, the degree of bending becomes smaller, so microbending loss tends to decrease. Therefore, if you make an optical fiber core that intentionally causes microbending loss by coating the optical fiber with a coating that tends to cause microbending loss, and store it in the longitudinal direction of the wire, it is possible to The microbending loss of the optical fiber will change in accordance with the change in tension. In other words, a relationship is obtained in which microbending loss decreases as wire tension increases. Therefore, by measuring the microbending loss of the optical fiber core wire housed in the wire, the tension applied to the wire can be measured.

[Example] Hereinafter, an example of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a state in which an overhead ground wire 2 is installed between towers IA and IB of an overhead power transmission line. There is a second
As shown in the figure, an optical fiber core 3 in which microbending loss has been generated in advance is stored. One end of this optical fiber core 3 is connected to an optical aS such as an LED or LD via a non-metal optical cable 4 for reading, and the other end is connected to an optical power meter 7 via a non-metal optical cable 6 for reading. ing. The relationship between the tension of the overhead ground wire 2 and the optical loss of the optical fiber core 3 is determined in advance through experiments or the like.

In this way, the tension of the overhead ground wire 2 can be measured by measuring the optical loss of the optical fiber core 3 based on the change in the tension of the overhead ground wire 2 with the optical power meter 7.

Since the optical fiber core wire 3 and the straight optical cable 4.6 have high insulation properties and are non-inductive, tension measurement can be performed without being affected by high voltage and magnetic fields.

Using this measurement method, it is possible to measure, for example, the amount of icing clouds and wind pressure on overhead power transmission lines, and it is also possible to measure abnormal vibrations that accompany tension fluctuations, making it possible to obtain maintenance information on overhead power transmission lines. It is extremely convenient. Furthermore, the measuring method of the present invention can also be used to monitor the tension of electric wires in overhead lines.

In addition, if two coated optical fibers are housed in an electric wire, at least one of them is made into a coated optical fiber with microbending loss generated in advance, and they are connected at one end to form a series of coated optical fibers, All measurement work can be done with just one end.

Furthermore, in the case where abnormal tension is applied locally, it is recommended to use an 0TDR (optical pulse tester) to find out the position where the abnormal tension is applied.

〔Effect of the invention〕

As explained above, according to the present invention, wire tension can be measured optically using optical fibers, so tension can be measured without being affected by voltage or magnetic fields. . Additionally, tension can be measured in places where conventional tension meters cannot be used.

[Brief explanation of drawings]

FIG. 1 is an explanatory view showing an embodiment of the wire tension measuring method according to the present invention, and FIG. 2 is a longitudinal cross-sectional view of the wire in the same embodiment. IA/IB ~ Steel tower, 2 ~ Overhead ground wire (electric wire), 3 ~ Optical fiber core wire, 5 ~ Light source, 7 ~ Optical power meter.

Claims (1)

[Claims] Wire tension, characterized in that the tension applied to the electric wire is measured by storing an optical fiber core in which microbending loss has occurred in advance in an electric wire and measuring the optical transmission loss of the optical fiber core. Measuring method.