JPH01302174A - Current measuring apparatus - Google Patents

Abstract

PURPOSE:To measure current in a high voltage electric wire with a high insulation reliability, by performing a spatial transmission of light between a light transmitter, light receiver and an optomagnetic sensor. CONSTITUTION:An optomagnetic field sensor 2 is mounted on a high-voltage electric wire A. Light emitted from a light transmitter 1 is made parallel with a lens 7a. The parallel light is incident into a prism 8a passing a space (in a direction B) and after the course thereof is bent by 90 deg., it is linearly polarized with a polarizer 3. The light thus linearly polarized is turned in polarizing plane in proportion to the intensity of a magnetic field generated depending on the size of a current flowing through the high-voltage electric wire A while passing through a Faraday element 4 to be modulated in intensity with a detector 5. The light thus modulated in intensity is outputted to a signal processing circuit 9 through prisms 8b and 7b and a light receiver 6. The signal processing circuit 9 measures the current of the high-voltage wire A by an electrical signal being inputted.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a current measurement method that measures the magnitude of current flowing through a high-voltage electric wire installed in an indoor substation, etc. using an optical magnetic field sensor that utilizes the Faraday effect. This relates to a measuring device.

[Conventional technology]

It is well known that the Faraday effect can be used to measure the current flowing through an electric wire.
111 is a block diagram showing the configuration of the conventional current measuring device shown in P.

In the figure, reference numeral 1 denotes an optical transmitter, to which the end face of a light transmitting optical fiber 31 is connected, and the other end face of the light transmitting optical fiber 31 is connected to a microelectromagnetic field sensor 2. It is in contact with the lens 32. The optical magnetic field sensor 2 includes the microlens 32, the polarizer 3, the Faraday element 4. It is constructed by optically coupling an analyzer 5 and a microlens 33. An end face of a light-receiving optical fiber 34 is in contact with the microlens 33, and the other end face of the light-receiving optical fiber 34 is an optical receiver 6 that converts the amount of received light into an amount of electricity and outputs an electric signal. It is connected to the.

Next, the operation will be explained.

Light emitted from the optical transmitter 1 is introduced into the optical magnetic field sensor 2 through a light transmitting optical fiber 31. The light introduced into the optical magnetic field sensor 2 is converted into parallel light by the microlens 32 and linearly polarized by the polarizer 3. When the linearly polarized light wave emitted from the polarizer 3 is propagated in the Faraday element 4, its plane of polarization undergoes Faraday rotation depending on the strength of the magnetic field when an external magnetic field is parallel to the traveling direction of the light. be done. This rotation angle is converted into intensity modulation by the analyzer 5, and the microlens 33. The light is passed through the light-receiving optical fiber 34 and subjected to optical/electrical conversion at the optical receiver 6. By measuring this electrical output, the external magnetic field to be measured around the optical magnetic field sensor 2 can be measured. Since the current flowing through the wire generates a magnetic field proportional to its value, the current flowing through the wire can be determined from the measured magnetic field.

[Problem to be solved by the invention]

In the conventional current measuring device as described above, the optical transmitter 1 and the optical magnetic field sensor 2 are connected by optical fibers, and the optical magnetic field sensor 2 and the optical receiver 6 are connected by optical fibers. If the resin of the outer covering deteriorates due to ultraviolet rays or the like, it becomes susceptible to salt damage and the insulation performance decreases. As a result, there is a problem that it cannot be used in high-voltage electric wires that have strict requirements for insulation performance.

Another drawback is that power transmission must be temporarily stopped in order to attach the optical magnetic field sensor to the electric wire.

The present invention has been made in view of the above circumstances, and is capable of spatially transmitting light between an optical transmitter, an optical receiver, and an optical magnetic field sensor, and also allows the optical magnetic field sensor to be attached to and detached from an object (electrical wire). By providing a mounting mechanism for attaching to
To provide a current measuring device which does not use an optical fiber so there is no need to worry about deterioration of insulation performance, can be used even on high-voltage electric wires, and does not require temporarily stopping power transmission when attaching an optical magnetic field sensor to the electric wires. The purpose is to

In addition, since the light from the optical transmitter to the optical magnetic field sensor and the light from the optical magnetic field sensor to the optical receiver have the same optical path, the optical axes of the optical transmitter, optical receiver, and optical magnetic field sensor can be aligned. The object is to provide a simple current measuring device.

Furthermore, it is an object of the present invention to provide a current measuring device in which the optical axes of the optical transmitter, the optical receiver, and the optical magnetic field sensor can be easily aligned by obtaining an image of the optical magnetic field sensor using light from the optical transmitter. shall be.

[Means to solve the problem]

The current measuring device according to the present invention has a configuration that spatially transmits light from a light transmitting section to a magneto-optical field sensor and light from a magneto-optic field sensor to a light receiving section, and also has a structure in which the magneto-optic field sensor is detachably attached to an object. It is characterized by having a mounting mechanism.

[Effect]

In the current measuring device of the present invention, the light emitted from the light transmitting section is incident on the optical magnetic field sensor through the space, and the light emitted from the optical magnetic field sensor is incident on the light receiving section through the space. Ru. Therefore, there is no need for an optical fiber for transmitting light, and there is no risk of deterioration in insulation performance due to deterioration of the optical fiber. Furthermore, since the optical magnetic field sensor can be detachably attached to the object using the attachment mechanism, the optical magnetic field sensor can be attached to the object without stopping power transmission.

In addition, the optical path of the light from the light transmitting section and the optical path of the light to the light receiving section coincide with each other, and alignment of the optical paths can be performed using only one optical path, making it easy to align the optical axes.

Furthermore, an image of the optical magnetic field sensor can be obtained.

Therefore, since the optical axis can be aligned by visually observing this image, the optical axis alignment operation is easy.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on drawings showing embodiments thereof.

FIG. 1 is a schematic diagram showing the configuration of a current measuring device according to the present invention. In the figure, A is a high-voltage electric wire as an object to be measured, 2 is an optical magnetic field sensor attached to high-voltage electric wire A, and 11 is a sensor placed on the ground. This figure shows the ground-side equipment.

High-voltage electric wire A is placed in the air, and the high-voltage electric wire A has
The optical magnetic field sensor 2 is attached by an attachment mechanism lO using a spring. The optical magnetic field sensor 2 has, from its incident side,
Prism 8a + polarizer 3. Faraday element 4. Analyzer 5
．． The prisms 8b are optically coupled in this order.

The ground-side device 11 includes an optical transmitter l that transmits light to the optical magnetic field sensor 2, a lens 7a that emits the light from the optical transmitter l as parallel light toward the optical magnetic field sensor 2 (prism 8a),
Based on the lens 7b that focuses the light from the optical magnetic field sensor 2 (prism 8b), the optical receiver 6 that receives the focused light from the lens 7b, converts it into an electrical signal and outputs it, and the output signal of the optical receiver 6. A signal processing circuit 9 is provided for measuring the current of the high voltage electric wire A.

Next, the operation will be explained.

First, the optical magnetic field sensor 2 is attached to the high-voltage electric wire A by attaching the attachment mechanism 10 to the high-voltage electric wire A using an insulating rod.

The light emitted from the optical transmitter 1 becomes parallel light at the lens 7a. This parallel light passes through space (in the direction of arrow B), enters the prism 8a, and after its path is bent by 90',
The light is linearly polarized by the polarizer 3. While the linearly polarized light (linearly polarized wave) passes through the Faraday element 4, its plane of polarization rotates in proportion to the strength of the magnetic field generated by the magnitude of the current flowing through the high-voltage wire A, and is detected. The intensity is modulated by photons 5.

After the path of the intensity-modulated light is bent by 90'' at the prism 8b, it passes through space again (in the direction of arrow C) and enters the prism 7b (ground-side device 11), where it becomes a focused light.

The focused light is received by the optical receiver 6 and photoelectrically converted, and an electrical signal corresponding to the amount of light is output to the signal processing circuit 9. The signal processing circuit 9 measures the current of the high voltage Tl line A based on the input electric signal.

In this embodiment, the ground side device 11. Since light is spatially transmitted between the optical magnetic field sensors 2, there is no need for an optical fiber for light transmission unlike in the past, so insulation reliability is high and current in high voltage electric wires can be measured. Further, since the optical magnetic field sensor can be freely attached to and removed from the electric wire, there is no need to stop power transmission when the optical magnetic field sensor is attached.

FIG. 2 is a schematic diagram showing the configuration of another embodiment of the current measuring device according to the present invention, in which A is a high-voltage electric wire, 2 is an optical magnetic field sensor, 11 is a ground-side device, and the high-voltage electric wire A As in the previous embodiment, the optical magnetic field sensor 2 is mounted on the mounting mechanism 10 using a spring. The magnetic field sensor 2 in this embodiment is composed of a Faraday element 4 and a reflective film 14 attached to one end surface of the Faraday element 4, and the polarizer 3 and analyzer 5 are housed in the ground-side device 11. has been done.

The ground side device 11 includes the above-mentioned polarizer 3. In addition to the analyzer 5, there is an optical transmitter 1 that transmits light, a lens 7a that converts the light from the optical transmitter 1 into parallel light, and a single optical path that connects the light from the polarizer 3 and the light to the analyzer 5. an optical filter 1 that transmits only light in the same wavelength range as the light from the optical transmitter 1;
5. Lens 7b that focuses the parallel light that has passed through the analyzer 5
, an optical receiver 6 that receives the focused light from the lens 7b, converts it into an electrical signal and outputs it, a signal processing circuit 9 that measures the high voltage electric & JIA current based on the output signal of the optical receiver 6, and an optical magnetic field sensor. a light distributor 1 that distributes a portion of the return light from 2;
3. Lens 7c that focuses the distributed light from the optical splitter 13
, and a semi-transparent plate 16 that receives the focused light from the lens 7c and forms an image of the optical magnetic field sensor 2.

Next, the operation will be explained.

As in the previous embodiment, first, attach the attachment mechanism 10 to the high-voltage wire A using an insulating rod.
Attach the optical magnetic field sensor 2 to the high voltage electric wire A.

The light emitted from the optical transmitter l becomes parallel light by the lens 7a, and then linearly polarized by the polarizer 3 to become a linearly polarized light wave. The course of the linearly polarized light wave is 90° at the optical combiner/distributor 12.
After being bent and passing through the light distributor 13, the ground side device 11
Go outside. The linearly polarized light wave exiting the ground-side device 11 passes through space (in the direction of the arrow) and enters the optical magnetic field sensor 2 (Faraday element 4). While passing through the Faraday element 4, the plane of polarization of the linearly polarized light wave rotates in proportion to the strength of the magnetic field generated by the current flowing through the high-voltage wire A, and is then reflected by the reflective film 14 to return to the original optical path. During the return, the plane of polarization is further rotated by the same angle as the rotation angle of the plane of polarization.

The linearly polarized light wave whose polarization plane has been rotated according to the strength of the magnetic field is emitted outside the optical magnetic field sensor 2, passes through the space along the same optical path as before (in the direction of arrow E), and returns to the inside of the ground-side device ll. incident on .

The linearly polarized light wave incident on the ground side device 11 is transmitted to the optical splitter 1
A part of the light is refracted by the light splitter 1, and most of the remaining light is refracted by the light splitter 1.
3 and the light combiner/distributor 12, and is transmitted through the optical filter 19 to remove the disturbance light. The linearly polarized light wave from which the disturbance light has been removed undergoes intensity modulation at the analyzer 5, and then passes through the lens 7.
b, and the focused light enters the optical receiver 6.

The optical receiver 6 receives this focused light, performs photoelectric conversion, and outputs an electric signal corresponding to the amount of light to the signal processing circuit 9. The signal processing circuit 9 measures the current of the high-voltage electric wire A based on the input electric signal.

The light refracted by the optical distributor 13 is focused by the lens 7c, and the image of the optical magnetic field sensor 2 is formed on the semi-transparent plate 16.

In this embodiment, as in the previous embodiment, the ground side device 11
．． Since light is spatially transmitted between the optical magnetic field sensors 2, it is possible to stop measuring the current in the high voltage electric wire, and there is no need to stop power transmission when the optical magnetic field sensors 2 are attached.

By the way, the current measuring device of the present invention, which is configured to measure the current of a distant object (electrical wire) by using spatial transmission of light without using an optical fiber as a transmission medium, can be used on the ground. Side device 11. It is necessary to accurately set the optical axis between the optical magnetic field sensors 2.

In the above embodiment, the outgoing path of light (the optical path from the ground side device 11 to the optical magnetic field sensor 2) and the returning path of light (the optical path from the optical magnetic field sensor 2)
This makes it possible to match the optical path (from
Setting the optical axis between the two is relatively easy. Specifically, this optical axis setting can be performed as follows.

That is, after attaching the optical magnetic field sensor 2 to the high-voltage electric wire A, the ground-side device 11 is positioned so that the image of the optical magnetic field sensor 2 is located at the center of the semi-transparent plate 16, and then the image is emitted from the optical transmitter 1. When the ground-side device 11 is positioned so that the light returning from the magneto-optical field sensor 2 overlaps the image of the magneto-optical field sensor 2, this position becomes a position where the optical paths of the outward and return paths coincide. More precisely, the position of the ground-side device 11 is finely adjusted so that the electrical output of the optical receiver 6 is maximized.

All the operations for setting the optical axis as described above can be performed at a position away from the high-voltage electric wire A (on the ground side), so the operations are easy.

In the above example, the optical filter 15 is provided in the ground-side device 11 in order to remove errors due to the influence of disturbance light other than the signal light, but it may be built in the optical receiver 6 in advance. , or may not be provided if the error due to the influence of ambient light can be ignored.

Furthermore, even if an optical system (light distributor 13, lens 7c, and semitransparent plate 16) for obtaining an image of the magneto-optical field sensor 2 is not provided, the optical path can be set by making the optical paths of the outgoing and returning paths coincide. Ease of work is preserved.

〔Effect of the invention〕

As detailed above, the current measuring device of the present invention spatially transmits light between the optical transmitter, the optical receiver, and the optical magnetic field sensor, so it has high insulation reliability and can measure current even in high-voltage electric wires. be able to.

Further, since a mounting mechanism for attaching the optical magnetic field sensor to the object is provided, there is no need to stop power transmission to the object when attaching the optical magnetic field sensor.

In addition, since the optical path to the optical magnetic field sensor and the optical path from the optical magnetic field sensor are the same, the optical axis alignment between the optical transmitter, optical receiver, and optical magnetic field only needs to be done once, and the operation is simple. be.

Furthermore, since the optical path can be set while visually observing the image of the optical magnetic field sensor, the above-mentioned optical axis alignment is easy.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing the configuration of a current measuring device according to the present invention, FIG. 2 is a schematic diagram showing the configuration of another embodiment of the current measuring device according to the present invention, and FIG. 3 is a conventional current measuring device FIG. 1... Optical transmitter 2... Optical magnetic field sensor 3... Polarizer 4... Faraday element 5... Analyzer 6...
- Optical receiver 10... Mounting mechanism 11... Ground side device 12... Optical combiner/distributor 13... Optical distributor 16...
・Semi-transparent plate A...High-voltage electric wire In the figures, the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A current measuring device that measures the current of an object using the Faraday effect, comprising: an optical magnetic field sensor that is attached to the object and is sensitive to changes in a magnetic field; a light transmitting section that transmits light to the magnetic field sensor; a light receiving section that receives light from the optical magnetic field sensor via space; and a current detecting section that detects the current of the object based on the received light intensity of the light receiving section. A current measuring device comprising: and an attachment mechanism for detachably attaching the optical magnetic field sensor to the object. 2. The optical path of the light from the light transmitting unit and/or the light to the light receiving unit is adjusted so that the optical path from the light transmitting unit to the optical magnetic field sensor and the optical path from the optical magnetic field sensor to the light receiving unit match. 2. The current according to claim 1, further comprising: an optical path changing means for changing the current; and an imaging means for forming an image of the magneto-optical field sensor obtained by light transmitted from the light transmitting section and passed through the magneto-optical field sensor. measuring device.