JP2656833B2 - Optical current transformer - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an optical current transformer used for detecting a current flowing through a bus such as a disconnector.

(Prior Art) As a current transformer for detecting a current flowing through a bus such as a disconnector, there is an optical current transformer including a core having a shape surrounding the bus and an optical sensor. However, in this type of conventional post-current transformer, the core and the optical sensor were integrally housed inside an airtight case, so the shape of the core became large. There was a disadvantage that it could not be mounted. In addition, since it is necessary to use optical current transformers having cores of various shapes according to the shape of disconnectors, etc., it is necessary to prepare various types of optical current transformers corresponding to the types of disconnectors, etc. was there.

(Problems to be Solved by the Invention) The present invention solves the above-mentioned conventional problems and can be mounted on a known disconnector, and can easily cope with a change in the shape of the disconnector or the like. The present invention has been completed in order to provide an optical current transformer that can be reduced in size and cost.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides an optical fiber protection container having an airtight space for drawing out an optical fiber at the head of an insulator in which an optical fiber is incorporated. The optical sensor was mounted inside the sensor case protruding from its end, a core separable from the optical sensor was mounted on a conductor supported by the insulator, and the sensor case was inserted into a hole formed in the core. It is characterized by the following.

(Embodiment) Next, the present invention will be described in detail with reference to an embodiment of the illustrated optical current transformer for a disconnector.

(1) is an insulator incorporating an optical fiber (2),
(3) is an optical fiber protection container provided on the head of the insulator (1). The optical fiber protective container (3) has a space (4) for drawing out the optical fiber therein, and the optical fiber (2) drawn out of the insulator (1) is bent gently inside the space (4). Leading to the side. (5) is a vertical optical fiber housing formed on the side of the optical fiber protective container (3), (6) is a sensor case protruding from the upper end thereof, and (7) is a sensor case (6). ) Is an optical sensor mounted inside. As shown in the figure, the optical fiber (2) is wound inside the optical fiber housing (5), processed for extra length, and then the optical sensor (7) in the sensor case (6) via the connector (8). Is connected to The optical fiber storage section may be shared with the space (4). In this case, there is no vertical optical fiber storage vibration, and there is an advantage that the optical fiber storage section can be made compact. Also, the optical fiber protective container is
Generally, it is made of a metal such as aluminum, but if it is made of a ceramic or the like, it is possible to suppress an increase in the height of the insulator due to the installation of the storage portion. As the optical sensor (7), an element capable of extracting a current as the intensity of light using the Faraday effect in which the plane of polarization rotates according to the intensity of the magnetic field generated by the current is used. Thus, since the optical sensor (7) operates according to the strength of the magnetic field, the sensor case (6) is preferably made of a non-magnetically permeable material such as aluminum. In addition, sensor case (6)
In order to ensure long-term reliability of the optical sensor (7), it is preferable that the optical sensor (7) is hermetically sealed together with the optical fiber protective container (3) and the optical fiber housing (5). Further, instead of making the optical fiber protective container (3) and the optical fiber housing portion (5) airtight, the space (4) may be filled with a foaming resin, liquid silicone or the like. In this case, it is not necessary to maintain airtightness for a long time, and the reliability is improved. The cover (9) of the optical fiber housing (5) has a dehumidifier (10)
It is preferable that the optical fiber (2) and the optical sensor (7) are not adversely affected even if moisture enters the airtight space (4) or the like.

On the other hand, a conductor (12) is supported on the head of the insulator (1) by a mounting bracket (11). In this embodiment, the conductor (12) is a terminal plate constituting a part of the bus of the disconnector, but is not necessarily limited to this. Conductor (1
A core (13) is mounted around 2) to amplify the magnetic field generated by the current flowing through the conductor (12) and to reduce the effect of the magnetic field generated by the non-detection current. The core (13) is supported by the above-mentioned mounting bracket (11) by a bracket (not shown). In the present invention, the core (13) is attached to the optical sensor (7) and the sensor case (6). In contrast, it is separable. The core (13) is made by molding the outside of the iron core (14) made of silicon steel plate with epoxy diene or rubber to increase durability, but it is necessary to store the whole inside the airtight case as before. Since the simple molding process is sufficient, the size of the entire core can be reduced. A hole (15) is formed below the core (13), and a sensor case (6) containing the optical sensor (7) is inserted into the hole (15) of the core (13).

It is desirable to obtain an optimum value for the size of the core (13) from the detection current and the magnetic field-modulation degree characteristics of the optical sensor. The magnetic field generated in the gap of the core (13) largely depends on the size of the core (13), particularly on the gap length. FIG. 3 shows an example of the gap length of the core (13) and the basic characteristics of the magnetic field generated in the gap. It is preferable that a space between the outer surface of the sensor case (6) and the inner surface of the hole (15) is filled with a molding material such as silicone rubber in order to prevent relative vibration.

(Operation) In the optical current transformer of the present invention thus configured, the magnetic field generated by the current flowing through the conductor (12) supported by the insulator (1) is amplified by the core (13), and then the core (13) is amplified. ) Is converted into an optical signal by an optical sensor (7) in a sensor case (6) inserted into the hole (15) of (1), and is extracted to the ground side of the insulator (1) through an optical fiber (2). The ability to accurately extract the magnitude of the current flowing through the conductor (12) as an optical signal is no different from a conventional optical current transformer. However, since the optical current transformer of the present invention has a structure in which the core (13) and the sensor part can be separated, it is an optical sensor.
When it is necessary to keep (7) airtight, only the optical sensor (7) needs to be kept airtight, and it is not necessary to house the entire core (13) in an airtight case. Therefore, since the core (13) can be simply molded, the entire core (13) can be reduced in size, cost can be reduced, and the core (13) can be attached to an existing disconnector. Become. In addition, since the sensor case (6) may be inserted into the hole (15) of the core (13) after the core (13) is first attached to the conductor (13), it is convenient for attaching to an existing disconnector or the like. . Furthermore, only the core (13) can be replaced according to the shape of the disconnector, and the sensor part can be used in common,
It is not necessary to prepare various types of AC devices as in the case where the core and the sensor unit are integrated as in the related art, and it is possible to easily cope with various types of disconnectors and the like. In addition, the optical sensor (7) is housed inside a sensor case (6) having an airtight structure, and the optical fiber (2) connected to the optical sensor (7) is also housed in the optical fiber housing (5) and the optical fiber protective container (5). Since the airtight space (4) of (3) is accommodated with a sufficient space, long-term reliability of the sensor part can be ensured.

In particular, if the optical fiber housing (5) is vertical as in the embodiment, the distance between the head of the insulator (1) and the sensor case (6) can be reduced. It is suitable for mounting.

(Effects of the Invention) As described above, the present invention has a structure in which the core and the sensor portion are separable, so that the core can be reduced in size and can be attached to an existing disconnector or the like. At the same time, the cost can be reduced by simplifying the structure. Further, it is possible to easily cope with disconnectors and the like of various shapes only by replacing the core. Moreover, in the present invention, there is also an advantage that long-term reliability can be ensured by keeping the optical sensor or optical fiber airtight, or by embedding it in a foaming resin or liquid silicone. Therefore, the present invention greatly contributes to industrial development as an optical current transformer that has eliminated the conventional problems.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing an embodiment of the present invention, FIG. 2 is a left side view thereof, and FIG. 3 is a graph showing a relationship between a gap length and a magnetic field in the gap. (1): insulator, (2): optical fiber, (3): optical fiber protective container, (4) space, (6): sensor case,
(7): Optical sensor, (12): Conductor, (13): Core, (1
5): Hole.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hiroyuki Katsukawa 62, Inaba, Takagi, Fuso-cho, Niwa-gun, Aichi Prefecture (72) Inventor Hiroyuki Abe 1-30-30 Misono-cho, Anjo-shi, Aichi Prefecture (72) Invention Person Yasuhisa Sakurai 812 Niibori, Komaki City, Aichi Prefecture (56) References JP-A-61-157208 (JP, A)

Claims (3)

(57) [Claims] An insulator (1) incorporating an optical fiber (2).
An optical fiber protective container (3) having a space (4) for drawing out an optical fiber is provided at the head of the optical sensor, and an optical sensor (7) is mounted inside a sensor case (6) protruding from the end thereof. A core (13) that can be separated from the optical sensor (7) is attached to a conductor (12) supported by the insulator (1), and a sensor case (6) is attached to a hole (15) formed in the core (13). An optical current transformer characterized by being inserted. 2. An optical current transformer according to claim 1, wherein each connecting portion has a packing structure so as to keep the space (4) airtight. 3. An optical current transformer according to claim 1, wherein the space (4) is filled with a foaming resin, liquid silicone or the like.