JPH03211431A - Optical fiber temperature sensor for electric conductor short-circuit detection - Google Patents

Abstract

PURPOSE:To speedily detect an electric conductor being short-circuited and to specify the position of the short-circuit occurrence place by housing a fiber sensor in a jacket which is arranged along the electric conductor whose short circuit is to be detected and generates heat with the short-circuit current of the electric conductor. CONSTITUTION:If the electric conductor 5 is short-circuited, the short-circuit current flows and this short-circuit current flows even to the jacket 7 of an optical fiber sensor part 2 to generate heat with the large electric resistance of the jacket 7 at the position where the short-circuit current flows, and the generated heat is detected by checking the amplitude variation, phase shift, polarization plate variation, etc., of scattered light to detect whether or not the electric conductor 5 is short-circuited. Thus, the short-circuit occurrence of the electric conductor 5 is detected speedily and the distribution of the electric conductor temperature is measured by the sensor fiber 6 to specify the position of the short-circuit occurrence at the same time.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an optical fiber temperature sensor that detects the occurrence of a short circuit in electric wires, and in particular enables the location of a short circuit to be specified.

l Conventional technology and its issues.

An insulating coating layer is formed on the surface of power lines that transmit electricity and communication lines that transmit signals to protect them.

By the way, when multiple overhead power transmission lines that transmit large amounts of electricity are laid in parallel at a certain distance, the distance between the overhead power transmission lines may become closer than when they were laid due to strong winds, etc.
It is known that arc discharge occurs during this time, causing a short circuit. It is also known that in the case of communication lines, the insulation coating deteriorates after long-term use, causing short circuits to occur at that portion. When a short circuit occurs in 1iIiI in this way, power transmission and communication become impossible, so when a short circuit occurs, it is desired to immediately detect and repair it.

Conventionally, the occurrence of short circuits in electric wires has been detected by comparing the difference in the amount of current between the power supply side and the receiving side (in the case of power lines, and by comparing the difference in the amount of current between the power supply side and the power receiving side in the case of power lines, and by comparing the difference in the amount of current between the This is done by monitoring the decrease in capacitance between sections, etc., and repairs are made immediately after a short circuit in the wire is detected.

However, with conventional short circuit detection methods, although the occurrence of a short circuit can be detected immediately, the location of the short circuit cannot be accurately determined, and it takes a long time to complete the repair of the electric wire.

This invention was made in view of the above circumstances, and T
The purpose of the present invention is to provide an optical fiber temperature sensor for detecting short circuits in electric wires, which can quickly detect short circuits in L wires and A, as well as determine the location of short circuits.
do.

,] To solve the problem, means D] The optical fiber temperature sensor for detecting wire short circuit of the invention is as follows:
A means to solve this problem is to house a sensor fiber in a jacket that is attached to the wire whose short circuit is to be detected and generates heat due to the short circuit current of the wire.

``Effect'' The short-circuit current of the IT line causes the outer jacket to generate heat, and this PM
By detecting this using a sensor fiber, short circuits in electric wires can be quickly discovered.

Furthermore, by measuring the distribution of electric wires, it is possible to identify the location where a short circuit occurs.

[Examples] Hereinafter, the present invention will be described in more detail with reference to Examples.

In this invention, the electric wires refer to power lines for power transmission, power cables, communication cables, wires with J attached, communication cables, as well as F2 conductive wires in general, including bare power wires, McNet wires, etc. do.

FIG. 1 shows an example of an optical fiber temperature sensor for detecting a short circuit in an electric wire (hereinafter simply referred to as a fiber-end temperature sensor) according to the present invention.

In FIG. 1, reference numeral I denotes a light source made of a semiconductor laser or the like, and the light emitted from this light source 1 is routed along an electric wire 5 such as an overhead power transmission cable via a splitter 3 made of a fiber-optic coupler or the like. The wave is guided into the end fiber sensor section 2 (hereinafter simply referred to as the sensor section) attached to the sensor section. The sensor section 2 detects temperature changes based on changes in the transmission state of guided light. Changes in the guided light within the sensor unit 2 can be measured as backscattered light by the detector 4, and this backscattered light is separated from the light emitted from the light source 1 by the splitter 3 and sent to the detector. 4. The temperature of the sensor section 2 can be measured by detecting amplitude changes, phase changes, polarization plane changes, etc. of the backscattered light with the detector 4.

This processor part: The short circuit current that flows between lj, t, and z and one electric wire 5.5 is immediately energized into the outer cover 7.)
In addition, it is attached to the N feeder wire that detects short circuits. Both FIGS. 2 and 3 show how the sensor section 2 is attached to the electric wire 5. In the example shown in FIG. In the example shown in FIG. 3, the sensor section 2 is attached so as to be wound around the outer peripheral surface of the electric wire 5.

In addition, in both FIGS. 2 and 3, the sensor section 2 is attached to the outside of the electric wire 5, or the sensor section 2 is attached to the outside of the electric wire 5.
It may be used by being inserted into the layer together with the conducting wire portion of the electric wire 5.

The sensor section 2 has a long sensor fiber 6 housed in a jacket 7, as shown in FIG. 4 in its longitudinal section and in FIG. 5 in its skin section, for example.

This outer cover 7 includes an electric wire 5 to which a sensor KS2 is attached.
Heat is generated by the short-circuit current that flows when a short circuit occurs, so it is possible to generate heat by passing through a metal. It is what it is.

The sensor fiber 6 has a long length and is housed in an outer jacket 7, with the remainder led out from the outer jacket 7.
As shown in the figure, one end is connected to a branch 3.

The sensor fiber 6 detects temperature changes as amplitude changes, phase changes, and polarization changes of backscattered light, and is a silica-based optical fiber of the Ginogle mode or multimode type. It may be a bare wire, a wire, or a cored wire. In addition, the coating materials for optical fibers include polyethylene (PE) and polyvinyl chloride (PVC).
, polypropylene (PP), tetrafluoroethylene (T
In addition to using polymer resins such as FE), steel,
Metals such as aluminum can also be used.

Furthermore, as shown in FIGS. 4 and 5, the sensor fiber 6 may be inserted into the outer cover 7 with a gap provided therein, or may be fitted without providing a gap. ) The principle of detecting a short circuit in the electric wire 5 using a fiber-tip temperature sensor such as the one described above is as follows.

When a short circuit occurs in the electric wire 5 and a short circuit current flows as well as in the outer sheath 7, heat is generated at the position where the short circuit current flows due to the large electrical resistance of the outer sheath 7. This heat generation can be detected by checking amplitude changes, phase changes, polarization plane changes, etc. of the backscattered light transmitted through the sensor fiber 6, and the details of the occurrence of a short circuit in the electric wire 5 can be detected. .

For example, Raman scattering type R-OTDR (Rama
nOptical Time Domain Ref
By measuring the temperature distribution along the length of the electric wire 5 to which the sensor section 2 is attached using an electometer or the like, it is possible to simultaneously identify the location where the short circuit occurs.

Note that the outer sheath 7 is not particularly limited as long as it generates heat due to short-circuit current and can detect the heat generated by the processor fiber 6 lever. As shown in the longitudinal and cross-sectional views, an outer cover 7 may be used in which a heating wire 9 made of a nickel-chromium alloy or the like is wound around the outer periphery of a metal base 8 made of stainless steel or the like.

[Effects of the Invention] As explained above, the optical fiber temperature sensor for detecting power line short circuits of the present invention has a sensor fiber housed in an outer jacket that generates heat due to the short circuit current of the electric wire. By attaching the sensor to the wire to be detected, the outer cover generates heat when a short circuit occurs, and this heat generation can be detected by the sensor fiber, so that short circuits in the wires can be quickly detected. Furthermore, if the wire temperature distribution is measured using a sensor fiber, the location of the short circuit can be determined at the same time.

[Brief explanation of drawings]

FIG. 1 is a schematic configuration diagram showing an embodiment of an optical fiber temperature sensor for detecting short circuits in electric wires according to the present invention, and FIGS. FIGS. 4 and 5 are enlarged views of the main parts showing the state of the temperature sensor and the attachment of the sensor part to the electric wire. FIGS. FIG. 4 is a schematic longitudinal sectional view, FIG. 5 is a schematic cross-sectional view, and FIGS. 6 and 7 are views of the sensor section of the temperature sensor for detecting wire short circuits according to the present invention. Fig. 6 is a schematic vertical cross-sectional view, and Fig. 7 is a schematic cross-sectional view of B showing other examples.Fiber end sensor section, electric wire, sensor fiber jacket, metal north, electric wire .

Claims (1)

[Claims] An optical fiber temperature sensor for detecting a short circuit in an electric wire, characterized in that the sensor fiber is housed in an outer jacket that is attached to an electric wire whose short circuit is to be detected and generates heat due to the short circuit current of the electric wire.