JPS6014196Y2 - Abnormal temperature detection device - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an abnormal temperature detection device, and particularly to an abnormal temperature detection device for a cable line using optical fiber.

As the demand for electricity has increased in recent years, the cable lines in power transmission and distribution systems have become multi-stranded and congested, so that when the cables generate heat due to the current, they interact with each other, causing the cable lines to locally reach abnormally high temperatures. be.

In order to prevent such dangers, conventional methods have been to install a large number of thermocouples on the cable line to monitor the temperature, or to install a temperature detection line along the cable line to detect changes in the electrical characteristics of the temperature detection line. Countermeasures were taken using a method to detect abnormal temperatures.

However, the method using thermocouples requires the installation of a large number of thermocouples to maintain detection accuracy, resulting in high costs.
The method using temperature sensing wires has the disadvantage that malfunctions may occur due to the induction of current flowing in the cable line.

The purpose of this invention is to provide a highly accurate and reliable abnormal temperature detection device for cable lines.The feature of this invention is to provide a highly accurate and reliable abnormal temperature detection device for cable lines. When the temperature rises abnormally, the reflectance or transmittance of the laser light passing through the optical fiber at the connection part close to the temperature rising part changes, and the amount of laser light returning to the light receiving element changes. It is in.

FIG. 1 is a perspective view illustrating an abnormal temperature detection device for a cable line, which is an embodiment of the present invention.

The optical fibers 1 are connected by a plurality of connecting portions 2 and arranged along a cable line 3 in a gentle curve.

The optical fiber end 4 faces the laser light source 5, and a semi-transparent mirror 8 is placed between the optical fiber end 4 and the laser light source 5 at an angle of 45°.

FIG. 2 is an enlarged sectional view of the connection portion of FIG. 1.

The end surfaces of the optical fibers 1 are inclined surfaces, and are sealed in a junction box 21 facing each other.

The junction box 21 is filled with a matching oil 22 having a refractive index close to the refractive index of the core of the optical fiber 1.

This matching oil 22- is liquid at room temperature,
When the temperature rises, it generates bubbles or evaporates to become a gas.

When the matching oil 21 is in a liquid state, the laser beam passing through the optical fiber 1 passes through the end face easily, but when it evaporates, the difference in refractive index with the optical fiber 1 increases, increasing the amount of reflected light.

In FIG. 1, a laser beam from a laser light source 5 passes through a semi-transparent mirror 8 and an end portion 4 of the optical fiber, travels through the optical fiber 1, reaches the connecting portion 2 where the temperature has increased, is reflected, and returns within the optical fiber 1.

When this reflected light reaches the semi-transparent mirror 8, a part of it is reflected in the right angle direction, enters the light receiving element 6, and the amount of the reflected light is detected by the detector 7.

That is, it can be known that an abnormally high temperature portion has occurred in the cable line 3.

In addition, using a pulsed laser beam as the laser beam,
If the configuration is configured to measure the time from the time the pulse is generated to the time the reflected light is received, abnormal temperatures can be detected by the increase in the amount of reflected light, and the position of the connection section 2 that has risen in temperature can be known to detect abnormal rises in the cable line. It is also possible to detect hot spots.

As described above, the cable line abnormal temperature detection device of the present embodiment has the effect of detecting a location of an abnormal temperature rise on the cable line and preventing a burnout accident of the cable line.

In the above embodiments, a liquid that vaporizes when the temperature rises was used as the matching oil, but the liquid is transparent at room temperature and becomes colored when the temperature rises, decreasing the light transmittance or vice versa. You may also use

Further, this abnormal temperature detection device can also be used for temperature monitoring of piping paths other than cable lines.

The abnormal temperature detection device of the present invention has the effect of being able to reliably detect abnormal temperature rises in cable lines, long pipe lines, etc. with high accuracy.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an abnormal temperature detection device for a cable line, which is an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of the connecting portion of FIG. 1. In the figure, 1 is an optical fiber, 2 is a connecting portion, 3 is a cable line, 5 is a laser light source, 6 is a light receiving element, 7 is a detector, 21 is a junction box, and 22 is matching oil.

Claims (1)

[Scope of Claim for Utility Model Registration] 1. An optical fiber having a plurality of connecting parts attached to a long member that has the possibility of locally rising to an abnormal temperature, a laser light source that sends laser light to this optical fiber, and the above-mentioned connecting parts. a light-receiving element and a detector for detecting the laser beam reflected and returned by the elongated member, and when the temperature of the elongated member abnormally rises, the reflectance of the laser beam of the connection portion close to the temperature rising portion is provided. Alternatively, an abnormal temperature detection device characterized in that the transmittance changes and the amount of the laser light returning to the light receiving element changes. 2. A utility model in which the above-mentioned connection part is a connection part in which a connection box in which the ends of the optical fibers are fixed facing each other is filled with matching oil that is in a liquid phase at normal temperature and changes to a gas phase when the temperature rises to an abnormal temperature. An abnormal temperature detection device according to registered claim 1. 3. The above-mentioned connection part is a connection part in which a fluid whose light transmittance changes depending on whether it is at normal temperature or when the temperature rises to abnormal temperature is sealed in a connection box in which the ends of the optical fibers are fixed facing each other. Abnormal temperature detection device according to scope 1. 4. The abnormal temperature detection device according to claim 1, 2, or 3, wherein the laser beam is a pulsed laser beam. 5. The abnormal temperature detection device according to claim 1, 2, 3, or 4, wherein the elongated member is a cable line for power transmission.