JPS59157909A - Power wire with temperature monitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power line, and more particularly to a power line with a temperature monitoring device.

The function of power lines is to transmit electrical energy.
Normally, since both the power transmission voltage and the power transmission current are large, a certain amount of heat is generated. Therefore, the power transmission capacity of power cables, including OF cables (oil-filt cables), is often determined according to the maximum temperature of the conductor from the viewpoint of the lifespan of the insulator.

Temperature rises in power lines are caused by copper loss, dielectric loss, or if external armor such as iron or aluminum is used, armor damage due to induced current that builds up in this armor, and due to heat generated by these. determined by how it dissipates. In addition, transformers, current transformers, etc. are installed in these power line systems as necessary, but these devices also have the problem of temperature rise. In particular, once the conductor temperature rises due to abnormal current flowing due to short circuits, ground faults, etc., or due to poor heat dissipation due to rise in ambient temperature, this causes an increase in conductor resistance.
This could lead to a breakdown of the entire power transmission system.

For example, taking a tunnel cable as an example, in the case of an OF cable, insulating oil is contained in the cable, and this expands as the temperature rises. is taken. Also,
In the case of a flat OF cable, the cross-sectional shape of the cable is made flat in advance to absorb an increase in oil volume due to heat. However, even these are not necessarily sufficient to prevent sudden temperature rises. Furthermore, in the case of plastic-insulated cables, the temperature
Two rises result in a decrease in breakdown voltage.

Considering these points, temperature management of power transmission systems is extremely important. However, the capacity of a power line is usually determined in advance in consideration of the usage environment, power demand, etc., and is not necessarily constantly monitored. The situation is also similar for substation equipment placed in the middle of the power transmission line, which is not always monitored, or even if it is monitored, it is only on an individual basis.

The present invention has been made in view of these circumstances, and an object of the present invention is to provide a temperature monitoring device (=j power line) that can remotely monitor the temperature of a power transmission system and quickly detect abnormalities.

According to this invention, optical fibers are arranged along the power line, and the optical fibers are connected by heat-sensitive optical fiber connectors arranged along the power line at appropriate intervals in the length direction of the power line, A feature of this method is that temperature changes in power lines are measured using changes in loss in the optical fiber system. In other words, a heat-sensitive optical fiber connector is built into the power line or attached to the power line, and is configured so that the connection state changes and loss increases when the temperature rises, and the heat-sensitive optical fiber connector has a temperature detection function. Connect the optical fiber along the power line via a fiber connector.

Hereinafter, one embodiment will be described with reference to the drawings.

A heat-sensitive optical fiber/to-fiber connector according to an embodiment of the present invention is comprised of a V-groove type connector 1, as shown in FIG. In this figure, the connector 1 is connected to the board 2 and the holding plate 3.
A V-groove 4 is formed in the substrate 2. This substrate 2 has a bimetallic structure, and is constructed by laminating two dissimilar metal plates 5.6 having different coefficients of thermal expansion. In this example, amber was used as the metal plate 5 on the low expansion side, and bronze was used as the metal plate 6 on the high expansion coefficient side.

Then, the optical fibers 7.8 are placed in the V-groove 4, and their end faces are abutted so that they are in close contact with each other. In this state, the holding plate 3 is attached to the substrate 2, and the optical fiber 7.8 is fixed within the V-groove 4.

At room temperature, as shown in FIG. ff52A, the end faces of the optical fibers 7.8 are in close contact with each other, and optical coupling between the end faces is maintained well. However, in the high temperature state F1, Fig. 2B
As shown in Fig. 2, the bimetallic structure causes warpage in the connector l. Therefore, an irregularity occurs in the optical coupling between the end faces of the optical fibers 7.8, and the transmission loss of the optical signal increases in this portion.

Therefore, the above-mentioned connector 1 is built into the power line or attached to the power line at an appropriate point where the temperature is to be detected, and the optical fiber 7, 8, etc. attached to the power line is connected to the power line using the connector 1. By connecting them to form an optical fiber system and measuring the attenuation of the optical signal transmitted to this optical fiber system, it is possible to remotely detect the temperature rise at the location where the connector l is placed. It becomes possible. Then, when the temperature returns to a steady state due to recovery from +11, etc.,
The warpage of the connector 1 described in 1- is reduced and the loss is reduced again. Since temperature detection can be performed reversibly in this way, there are no restrictions on the installation location and it can be applied to a wide range.

In addition to the configuration of the above embodiment, for example, as shown in FIGS. 3A and 3B, the optical fiber 7.
A heat-sensitive optical fiber connector 9 made of a material that expands in the length direction of the fiber optic connector 8 may also be used. In this case, the third
As shown in FIG. 3A, the end faces of the optical fibers 7.8 are in close contact with each other, resulting in a state of low loss, and in a high temperature state, as shown in FIG. 3B, the distance between the end faces increases, resulting in increased loss.

As described above with respect to the embodiments, according to the present invention, heat-sensitive optical fiber splicers, which cause an increase in loss when the temperature rises, are placed at required locations along power lines, and the heat-sensitive optical fiber splicers are used to connect power lines. By connecting an optical fiber along with the power transmission system and monitoring the increase in loss in the optical fiber system, the temperature of the power transmission system can be remotely monitored and abnormalities can be detected quickly. Since this heat-sensitive optical fiber connector changes reversibly with temperature, its range of application is widened and there are fewer restrictions on where it can be installed.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of one embodiment of the present invention, FIGS. 2A and B are schematic diagrams for explaining the operation of FIG. 1, and FIGS. 3A and B are schematic diagrams of another embodiment. . 1.9... Heat-sensitive optical fiber connection now 2... Board 3... Holding plate 4... V
Groove 5...Low expansion metal plate 6...High expansion metal plate 7.8...Optical fiber 1 Applicant: Fujikura Electric Wire Co., Ltd.) 1Ω

Claims (1)

[Claims] (1) Heat-sensitive optical fiber connectors are placed along the power line and at appropriate intervals along the length of the power line, and these connectors connect the optical fibers placed along the power line described in 2. A power line with a temperature monitoring device featuring: