JPH0743661Y2 - Optical magnetic field sensor mounting device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a device for detecting a current flowing through a cable, and in particular, an optical magnetic field sensor provided in a single-core cable flows in a cable of another phase arranged in close proximity. The present invention relates to a device for mounting an optical magnetic field sensor that enables detection without being affected by electric current.

(Prior Art) In order to know a current flowing through a power transmission cable or the like, or a state of a leakage current in the cable, a current detection means is provided for the cable, and the detection means causes the conductor of the cable, or It has been generally practiced conventionally to be able to detect a current flowing through a cable sheath. As a detection means therefor, an optical magnetic field sensor using a Faraday element is often used because of its relatively simple structure and high reliability. In a device such as the optical magnetic field sensor, the phenomenon that the Faraday element rotates the polarization plane of light according to the magnetic field strength is used to detect the strength of the magnetic field at the portion where the Faraday element is installed. It is a device used as a device. In such a magnetic field detector, a polarizer and a right-angle prism are arranged on both sides of a Faraday element, and an optical fiber is connected to these members via a lens, and a detection circuit between a light emitting unit and a light receiving unit is provided. I am configuring.

In the optical magnetic field sensor as described above, when the conductor of the cable is covered with a thick insulator, the sensitivity of the optical magnetic field sensor may decrease. Therefore, in the conventional detecting device using the optical magnetic field sensor, the supporting means for the optical magnetic field sensor as shown in FIG. 5 or FIG. 6 is used, and the supporting means is made of a magnetic material. It is being done to be able to increase the strength of the magnetic field sensed by the sensor.

In the conventional example shown in FIG. 5, the insulator 6 covering the conductor 5 of the cable 1 is covered with a cushion 8 made of rubber or the like, and a ring 25 made of cast metal is arranged around the cushion 8. The sensor 20 is arranged in the cutout portion of the ring 25.
Even when the conductor 5 of the cable and the sensor 20 are separated from each other, the change of the current flowing through the cable can be accurately detected by the ring 25 which is a magnetic body.

Further, in another conventional example shown in FIG. 6, the periphery of the cable 1 is covered with a band 26 made of a magnetic material, and the sensor 20 is attached via a mounting member 28 provided at a predetermined position of the band 26. It is provided. Then, the fixing of the band 26 is fixed to the cable by using a fixing portion 27 such as a fixing screw so that the sensitivity of the sensor can be increased as in the case of the ring made of casting shown in FIG.

(Problems to be Solved by the Invention) However, in the conventional device as described above,
In particular, when a cast ring or the like is used, the weight thereof becomes extremely large, and the sensor mounting member is troublesome to handle, and the burden on the cable becomes large. is there. Further, when the band configured as shown in FIG. 6 is used, the configuration of the portion where the sensor is provided for the band and the engaging member at the end of the band becomes complicated, and the labor of mounting is increased. There are problems such as requiring a lot of

In any of the conventional examples described above, it is necessary to dispose a rubber cushion or the like between the ring or band and the cable, and disposing the cushion may damage the surface of the cable insulator. Treatment is required so that there is no Therefore, when installing the sensor, it is necessary to perform extra work such as setting the position of the cushion accurately.

Further, when the magnetic body is configured as a band member,
There is a concern that the corners of the band may hit the surface of the insulator of the cable and damage it. And
If the surface of the insulator is scratched, it will also affect the insulation characteristics of the cable.Therefore, it is necessary to carry out the sensor installation work to prevent such problems and to improve work efficiency. The impact will occur.

(Purpose of the Invention) The present invention solves the above-mentioned drawbacks of the conventionally used device, and makes it possible to easily fix the sensor, and the band made of a magnetic material enables the other phase (EN) An apparatus capable of performing accurate measurement without influence, and an apparatus capable of fixing a band member composed of a thin silicon steel plate so as not to damage the surface of a cable by providing a coating with an elastic body. Is intended.

(Means and Actions for Solving Problems) The optical magnetic field sensor mounting apparatus of the present invention is provided with an optical magnetic field sensor for a cable, and is configured to detect the current flowing through the cable by the optical magnetic field sensor. Related to the device. In the present invention, the optical magnetic field sensor is arranged close to the cable, and the cable and the optical magnetic field sensor are fixed by being wound by using a band member made of a magnetic material so that the sensor can be covered from the outside. In addition to the above, the band member is formed by covering the entire periphery of a thin silicon steel plate with a rubber cover.

(Operation) In the optical magnetic field sensor mounting device of the present invention, as described above, the optical magnetic field sensor is positioned with respect to the cable surface, and the cable and the sensor are integrally mounted so that they are covered with a thin silicon steel plate. There is. Therefore, the magnetic field generated by the cable conductor current can be concentrated on the sensor, the influence of other phases is eliminated, and the magnetic field of a specific cable can be accurately measured. Further, in the present invention, since the band member made of a magnetic material is made of a thin silicon steel plate, flexibility can be imparted and the work of attaching the sensor to the cable surface can be easily performed. . Furthermore, since the surface of the magnetic band is covered with an elastic body such as a rubber cover, even if the edge portion of the band hits the surface of the cable insulator, the surface is not scratched.

(Embodiment) The configuration of the optical magnetic field sensor mounting device of the present invention will be described with reference to the illustrated example. In the embodiment of the present invention shown in FIG. 1, a sensor 20 is arranged on a cable 1 in which an insulator 6 is provided around a conductor 5 and the sensor 20 is connected to a band.
It is fixed to the cable 1 by 21.
As the sensor 20, an optical magnetic field sensor is used, the band 21 is made of a material having a high magnetic permeability such as a silicon steel plate, and the end portion of the band 21 is a normal stop band. The sensor is fixed and held around the cable by such means as fixing.

As the band 21 of the present invention, as shown in FIG. 1a,
A thin member made of a silicon steel plate is used, and a locking hole 21a is provided at one end thereof, and a locking projection 21b or the like is formed at the other end thereof. By engaging the locking projection 21b with the engaging hole 21a, the band 21 is fixed around the cable 1 and the sensor can be attached. Further, as the method of fixing the band 21, any other fixing mechanism can be used.

Further, as shown in FIG. 1b, the band 21 of the present invention is constructed such that the surface of the magnetic body 22 is covered with the rubber cover 23, or other surface protection means of the metal member is used. Can be configured. With such a configuration, the surface of the band can be protected, and the surface of the cable is prevented from being damaged by hitting the corners of the band.

Further, as described above, when the sensor 20 and the cable 1 are integrated with each other, the conductor current of the cable can be accurately detected by attaching the surface of the sensor 20 and the cable 1 with a band formed of a magnetic material, and other adjacent cables can be detected. It becomes possible to block the leakage magnetic field from the etc. by the band. The current state of only the cable to which the sensor is attached can be detected by the sensor with high accuracy. That is, in the device of the present invention, since the cable and the sensor are covered by a common band, the influence of the leakage magnetic field from the adjacent cable can be blocked by the band, and the magnetic field of the cable to which the sensor is attached is blocked. It is possible to detect with the above-mentioned sensor in the state where only the above is strengthened.

The sensor 20 of the present invention, which is fixed by the band as described above, is attached to the cable as shown in FIG. 2 or 3. The example shown in FIG. 2 is provided at the connecting portion of the cable 1, and the sensor 20 can be attached to the casing 12 of the connecting device 10 using the fixing means of the present invention.

Further, as a means for fixing the sensor 20 to the casing 12, the band 21 as described above is used, and for the connecting device 10 thereof, portions on both sides of the insulator 11 provided in the central portion thereof. The sensor can be fixed at any position. Further, the sensor of the present invention can be provided in the part of the branching device 15 which branches the single wire of each phase of the cable 3 as shown in FIGS. 3 and 3a. The branching device 15 branches the three-phase AC three-core cable 3 into branch lines 2a, 2b, and 2c for each phase of R, S, and T so that they can be connected to a load side such as a motor. .

A sensor can be provided on, for example, the S-phase branch line 2b in the central portion of the branch lines, and the measured value of the current detected by the sensor 20 depends on the current flowing through the single-core cables on both sides. Set to unaffected. That is, as a mounting member of the sensor 20, using the band 21 made of silicon steel plate as described above, the leakage magnetic field of the adjacent single core cable is blocked by the band 21, and only the magnetic field of the specific single core cable 2b is accurately measured. It can be detected.

In the embodiment of the present invention described above, as the material for forming the band, other than the above-mentioned silicon steel plate, any other material can be used. It is necessary to use a material having a very large magnetic permeability, such as a silicon steel plate, and a material that can be processed and mounted well.

As described above, as the sensor attached to the cable and used for measuring the current flowing through the cable, for example, an optical magnetic field sensor having a configuration as shown in FIG. 4 can be used. The optical magnetic field sensor 20 shown in FIG. 4 has a property of polarizing light depending on the strength of the magnetic field applied to the Faraday element, and the Faraday element is affected by the magnetic field of the cable. Used as a member.

In the optical magnetic field sensor shown in FIG. 4, a polarizer 33 is connected to one side of the Faraday element 35, and a light emitting unit 30 is connected to the polarizer 33 via a lens 32 and an optical fiber 31. To be done. A lens 38 is provided on the other side of the Faraday element 35 via an analyzer 36 and a right-angle prism 37.
And a light receiving section 40 is connected to the lens 38 via an optical fiber 39.

Then, the Faraday element 35 is attached to the location where the magnetic field is detected, and the light from the light emitting section 30 is emitted to the polarizer 33 through the optical fiber 31 and the lens 32 with respect to the Faraday element 35. The polarizer 33 linearly polarizes this light and outputs it to the Faraday element 35 as a linearly polarized wave. The Faraday element
The linearly polarized wave entering 35 is affected by the magnetic field and its plane of polarization rotates (Faraday effect), and is detected by the light receiving unit 40 via the analyzer 36, the right-angle prism 37, the lens 38, and the optical fiber 39. It As the lens shown in FIG. 4 described above, for example, a SELFOC lens (trade name) or the like can be used, and in addition, a normal rod-shaped lens can also be used.

In the Faraday element 35 of the present invention described above, when the incident light passes through the inside of the Faraday element, its polarization plane is rotated according to the strength of the magnetic field applied to the Faraday element, so that the analyzer The intensity of the light emitted from 36 is changed. The rotation angle of the plane of polarization in the Faraday element 35 increases as the magnetic field strength increases, and conversely, when the magnetic field strength decreases, the rotation angle decreases. Therefore, the intensity of the light emitted from the analyzer 36 is determined by the light receiving unit 40.
The magnetic field strength in the measuring section can be detected by the detection.

By using the above-mentioned optical magnetic field sensor as the sensor of the present invention, even when the sensor is separated from the conductor 5 of the cable 1, by covering it with a band, the cable can be accurately and without being affected by other phases. It is possible to measure the magnetic field strength and its change, and thereby to accurately measure the leakage current and the like in the cable line.

(Advantages of the Invention) Since the optical magnetic field sensor mounting device of the present invention has the above-mentioned configuration, the magnetic field from a specific cable is not affected by the leakage magnetic field from the cable of another phase. It is possible to accurately measure the change in (1) while being strengthened by the band. Therefore, the magnetic field created by the cable conductor current can be concentrated on the sensor, without being affected by the leakage magnetic field from the cable of other phase,
It is possible to accurately measure changes in the magnetic field from a particular cable with the band intensified.

Further, in the present invention, the band member made of a magnetic material is made of a thin silicon steel plate so that the band can be provided with flexibility, and the sensor is attached to the cable surface by using the band. Can be done easily. Further, in the present invention, the edge portion of the thin magnetic band easily bites into the cable insulator, but the entire band member of the present invention is covered with an elastic body such as a rubber cover. Therefore, even if the edge portion of the band member hits the surface of the cable insulator, the cable insulator is not damaged.

[Brief description of drawings]

1 is an explanatory view showing the construction of an optical magnetic field sensor mounting device of the present invention, FIG. 1a is a perspective view showing the construction of a band of the present invention, FIG. 1b is a sectional view of the band, and FIG. 2 is the present invention. FIG. 3 is an explanatory view of the case where the sensor is provided in the connecting device, FIG. 3 is an explanatory view of the case where the sensor is provided in the branching device, FIG. 3a is an explanatory view showing the relationship between each single wire and the sensor, and FIG. 4 is the sensor of the present invention. 5 is an explanatory view of a sensor mounting means of a conventional example, and FIG. 6 is an explanatory view of another conventional example. Symbols in the figure 1 ... Cable, 5 ... Conductor, 6 ... Insulator, 10 ...
Connection device, 15 …… Branching device, 20 …… Sensor, 21 …… Band, 22 …… Magnetic material, 23 …… Rubber cover, 25 …… Cast ring, 26 …… Band, 30 …… Light emitting part, 35 ...... Faraday element, 40 …… Light receiving part.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yukio Morita 4-3 Ikejiri, Itami City, Hyogo Prefecture Mitsubishi Cable Industries, Ltd. Itami Works (56) Reference JP-A-63-196866 (JP, A)

Claims (1)

[Scope of utility model registration request] 1. An apparatus configured to receive an optical magnetic field sensor with respect to a cable and to detect a current flowing through the cable by the optical magnetic field sensor, wherein the optical magnetic field sensor is arranged close to the cable, The cable and the optical magnetic field sensor are fixed by winding using a band member made of a magnetic material, and the sensor is configured to be covered from the outside, and the band member is a rubber cover covering the entire circumference of a thin silicon steel plate. A device for mounting an optical magnetic field sensor, characterized in that the device is covered.