JPS6259873A - Accident section discriminating device using photosensor - Google Patents

Abstract

PURPOSE:To decrease polarizers and analyzers in number and to obtain an inexpensive device of a simple constitution by arranging two magnetooptic effect elements across a polarization plane maintaining fiber so that the rotating directions of the planes of polarization to the same magnetic field are opposite each other. CONSTITUTION:The magnetooptic effect elements 11 and 12 are provided at both terminals of each section of a power distribution line and arranged and connected by the polarization plane maintaining fiber 14 so that the rotating directions of the plane of polarization of light passing through the elements 11 and 12 are opposite in a magnetic field produced with the same current in the power distribution line. Further, the element 11 and a polarizer 10 before it, and the element 12 and an analyzer 13 behind it are also connected by fibers 14 respectively and the polarizer 10 and analyzer 13 are connected to a measurement system 16 by optical fibers 15 respectively. Then if an accident occurs between the elements 11 and 12, currents flows through the elements 11 and 12 in the opposite directions and the rotation of the plane of polarization by the element 11 is not returned, but increased by the element 12, and consequently a signal modulated with the light output of the measurement system 16 appears eventually, thereby detecting that an accident point is in this section.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a fault section determination device for power transmission and distribution lines using optical sensors.

[Background Art and Pressure Points] An optical sensor having a magneto-optical effect, for example B50 (B
i+28 i020 single crystal), lead glass, etc., to detect the magnetic field generated by the energized 71I current in the power transmission and distribution line,
From this, a method of determining the magnitude of the conducting current ff1l+ has been put into practical use.

Furthermore, a device has been proposed that uses an optical sensor having such a magneto-optical effect to detect a faulty section of a power transmission/distribution line. FIG. 3 is an explanatory diagram thereof.

As shown in the figure, optical sensors 1 and 2 having a magneto-optic effect are arranged at both ends of a section of a power transmission line or a distribution line Q in close proximity to the line. 3.4 is the sensor 1, respectively.
, 2, and sends it back after being modulated by the magnetic field caused by the line current. 5 shows a measurement system, and the Z18 end of the optical fiber 3 that sends light to the sensors 1 and 2 is connected to a light source (not shown),
The terminal of an optical fiber 4 for optical transmission, which sends and returns light modulated by a magnetic field, is connected to a photoelectric element.

An optical sensor with a magneto-optic effect consists of a polarizer, a magneto-optic effect element, and an analyzer.Polarized light emitted from the polarizer causes rotation in the plane of polarization due to the strength of the magnetic field while passing through the magneto-optic effect element. Therefore, the light output through the analyzer changes its magnitude depending on the strength of the magnetic field, and appears as an electric signal on the charging element.

Therefore, use the same characteristics for both sensors 1 and 2,
Assuming that the In losses due to the respective optical fibers 3 and 4 are the same, and that there is no accident in the above-mentioned section,
Since the outputs of the photoelectric elements connected to the optical sensors 1 and 2 that have both magneto-optic effects are the same and in the same direction, in the measurement system 5, the outputs of the photoelectric elements must be input to the subtraction circuit for the outputs of both optical elements. In this case, the result of subtraction is zero.

Therefore, as shown in the figure, if the line breaks down within the section, the optical sensor 1 having a magneto-optic effect element,
The directions of the current flowing through the line at the position where 2 is placed are different from each other, and when the outputs from both optical 7R1 elements are calculated by a subtraction circuit, there is a certain output, which causes a failure to occur within the section. can be detected.

Furthermore, when the above-mentioned accident occurred in another section, sensors 1 and 2 in this section were under the same shadow and snow, and the calculation result by the subtraction circuit showed zero, making it impossible to falsely detect an accident in another section. do not have.

By the way, according to the above-mentioned failure section detection device, since a subtraction circuit is required, and furthermore, the sensor optical signal must be processed after being converted into electricity, which is complicated. In addition, one of the sensors that has the magneto-optic effect, one of which is independent, such as a polarizer, a magneto-optic effect element,
It is expensive because it needs to be equipped with an analyzer.

[Means for Solving the Problem] As mentioned above, the present invention has been made for the purpose of improving the complexity and high cost of configuring an accident zone discriminating device using conventional optical sensors. , for each section of the power transmission and distribution line, a first magneto-optic effect element and a second magneto-optic effect element are installed at both ends of the section, and the first magneto-optic effect element and the second magneto-optic effect element are The first magneto-optical element is connected by a polarization-maintaining fiber and arranged so that the rotation of the polarization plane of light passing through the magneto-optic effect element is in the opposite direction due to a magnetic field generated by the same current in the power transmission and distribution line. The effect element is connected to the front-stage polarizer, and the second magneto-optic effect element is connected to the rear-stage photoreceptor through polarization-maintaining t,v fibers, and the polarizer and analyzer are connected to the measurement system through optical fibers, respectively. An accident zone determination device using an optical sensor is characterized in that:

The present invention will be explained below with reference to embodiments shown in the drawings.

In FIG. 1, 10 is a polarizer, I+ and 12 are first and second magneto-optical effect elements made of, for example, BSO, and I3 is an analyzer. Magneto-optic effect element I! ,+2
is placed close to the electric wire at a predetermined monitoring position in one section of the power transmission and distribution line Q.

In this case, the magneto-optic effect elements I+ and +2 have the same characteristics, and the magneto-optic effect elements 11 and 12 are connected by a polarization-maintaining fiber 14 to maintain the polarization plane of light for the same magnetic field. Arrange so that the direction of rotation is opposite. Further, the polarizer 10 and the magneto-optic effect element 11 and the magneto-optic effect element 12 and the analyzer 13 are also connected by the polarization maintaining fiber 14 .

A polarization-maintaining fiber is an optical fiber that has the property of being able to send a polarization plane that lies at a certain angle with respect to the same reference line to the next stage of equipment, elements, etc., without changing that angle.

The polarizer 10 and the analyzer 13 are connected to the measurement system 1G side through optical fibers 15, respectively. The end of the optical fiber 15 to the polarizer 10 is connected to a light source, and the end of the optical fiber I5 to the analyzer 13 is connected to a photoelectric element.

If there is no abnormality in the section where the magneto-optic effect element II; +2 is placed, the current always flows in the same direction.
The polarization plane of the emitted light is rotated by the magneto-optic effect element II, and then returned to its original state by the magneto-optic element 12. As a result, the return input to the measurement system 16 is not affected by the alternating current. Become.

The accident occurred when the magneto-optical effect element 11. The same applies to the case where the error occurs outside of +2.

On the other hand, if an accident occurs between the magneto-optic effect elements II and +2, the currents to the magneto-optic effect elements 11 and 12 will be in opposite directions, and the rotation of the plane of polarization in the magneto-optic effect element 11 will be greater than that at +2. Rather, it is doubled, resulting in an alternating current modulated signal in the light output of the measuring system 16, by means of which it is possible to detect that the fault point is in this section.

FIG. 2 shows another embodiment of the invention. In this embodiment, a polarization analyzer 17 is used, and the polarization analyzer 17 is connected to two magneto-optic effect elements 11 and 12 by a polarization maintaining fiber 14, and the polarization plane between the two magneto-optic effect elements II and 12 is also Retention fiber! Connected with 4, polarized analyzer 17 and measurement system! It is connected to the 6 side by an optical fiber 15. In this case, as already explained, due to the connection of the polarization maintaining fiber 14, the two magneto-optic effect elements 11 and 12 rotate the polarization plane of light in opposite directions in response to a magnetic field of the same magnitude and direction. It goes without saying that such an arrangement should be adopted.

INDUSTRIAL APPLICABILITY The present invention can be used to determine electrical accident sections of cables, overhead lines, pipe air conductors, crystal-type power transmission and distribution lines for station equipment, etc.

[Effect] As already explained, conventionally, two sets of optical sensors each including a polarizer, a magneto-optic effect element, and an analyzer were required in one section, but in the present invention, two sets of optical sensors each having a polarizer, a magneto-optic effect element, and an analyzer are required to maintain the polarization plane. The direction of rotation of the plane of polarization of light is opposite to that of the same magnetic field through the fiber, and polarization is also applied between the polarizer and one magneto-optic effect element and between the analyzer and the other magneto-optic effect element. By connecting with a wavefront maintaining fiber, not only can the number of polarizers and analyzers be reduced, but the measurement system connected to them can be made simple and does not require a subtraction circuit. . Note that it is clear that similar effects can be achieved when using a polarized analyzer that is a combination of a polarizer and an analyzer.

[Brief explanation of drawings]

1 and 2 show an embodiment of the present invention. FIG. 3 is an explanatory diagram of a conventional fault section determination device for power transmission and distribution lines. 10... Polarizer, I+, +2... Magneto-optic effect element, +3... Analyzer, +4... Polarization maintaining fiber,
+5...Optical fiber, +6...Measurement system, 17
...Polarized analyzer. Mo 1 concave 3 figures

Claims (2)

[Claims] (1) For each section of the power transmission and distribution line, a first magneto-optic effect element and a second magneto-optic effect element are installed at both ends of the section,
A first magneto-optic effect element and a second magneto-optic effect element are connected by a polarization maintaining fiber, and rotation of the polarization plane of light passing through the magneto-optic effect element is caused by the same current in the power transmission and distribution line. Arranged so that the generated magnetic field is in the opposite direction,
The first magneto-optic effect element is connected to a front-stage polarizer, and the second magneto-optic effect element is connected to a rear-stage analyzer through a polarization maintaining fiber, and the polarizer and analyzer are each connected to an optical fiber for measurement. An accident zone determination device that uses an optical sensor and is characterized by being connected to a system. (2) An accident zone determination device using an optical sensor according to claim 1, characterized in that a polarizer and an analyzer are integrally constructed.