JP2590674Y2 - Double ratio current transformer - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a double ratio current transformer capable of switching a current transformation ratio.

[0002]

2. Description of the Related Art There is known a double ratio current transformer in which a wide range of current can be transformed with high accuracy by switching a current transformation ratio. As shown in Japanese Patent Application Laid-Open No. 62-183103, a conventional current transformer of this type includes a metal container filled with an insulating gas, a ring-shaped iron core, and a secondary coil wound around the iron core. An annular secondary unit disposed in a metal container having: and a second unit provided in a state penetrating the inside of the secondary unit, both ends being led out of the metal container, and one end being electrically connected to the metal container. Connected tubular outer 1
A secondary conductor and an inner primary conductor disposed inside the outer primary conductor and insulated from the outer primary conductor,
By connecting the outer primary conductor and the inner primary conductor in series or in parallel with a connection fitting, the primary circuit is switched over to two turns or one turn to switch the current transformation ratio.

[0003]

The conventional double-ratio current transformer uses different fittings depending on whether the outer primary conductor and the inner primary conductor are connected in series or in parallel. However, there is a problem in that the work when switching the connection becomes complicated. Further, in the conventional current transformer, it is necessary to store the detached connection fitting after switching the connection, which is troublesome.

The purpose of the present invention is to provide an outer primary conductor and an inner primary conductor.
To provide a double ratio current transformer capable of switching the number of turns of a primary circuit simply by selecting terminal fittings provided at ends of both primary conductors without switching connection of a secondary conductor. It is in.

[0005]

According to the present invention, a metal container filled with an insulating gas, a ring-shaped iron core and a secondary coil wound around the iron core are arranged in the metal container. An annular secondary unit, a tubular outer primary conductor provided through the inside of the secondary unit and having both ends led out of the metal container and one end electrically connected to the metal container; Concentrically disposed inside the primary conductor and
The present invention relates to a double ratio current transformer having an inner primary conductor insulated from a secondary conductor.

In the present invention, opposite ends of the outer primary conductor and the inner primary conductor are connected to each other by a connecting conductor provided outside the metal container, and the outer primary conductor and the inner primary conductor are connected to each other. A primary conductor is connected in series, and first and second terminal fittings are respectively provided at ends located on the same side of the outer primary conductor and the inner primary conductor, and the first and second terminal fittings are provided. A third terminal fitting is attached to an end of the outer primary conductor and the inner primary conductor located on the opposite side that is not directly connected to the connection conductor.

[0007]

As described above, the outer primary conductor and the inner primary conductor are connected in series by the connection conductor, and the first to third terminals are provided at predetermined ends of the outer primary conductor and the inner primary conductor. When the metal fittings are provided, the number of turns of the primary circuit can be switched only by appropriately selecting and using the first to third terminal fittings. For example, in a state where the third terminal fitting is connected to the line on the load side, of the first terminal fitting and the second terminal fitting, the terminal fitting that is not directly connected to the connection conductor is connected to the line on the power supply side. When used, the outer primary conductor and the inner primary conductor can be connected in series to make the number of turns of the primary conductor “2”. Of the first terminal fitting and the second terminal fitting, When the terminal fitting directly connected to the connection conductor is connected to the line on the power supply side, only one of the outer primary conductor and the inner primary conductor (the one provided with the third terminal fitting) is used as the primary conductor. The number of turns of the next circuit can be set to “1”.

As described above, according to the present invention, it is possible to switch the number of turns of the primary circuit and to switch the current transformation ratio only by selecting the terminal fitting, and to connect the outer conductor and the inner conductor in series or in parallel. Since it is not necessary to switch back to the above, the handling of the double ratio current transformer can be facilitated. Also 2
Unlike conventional double-ratio current transformers that switch between the outer conductor and the inner conductor using different types of connection fittings, there is no need to store unused connection fittings, simplifying maintenance and management. can do.

[0009]

1 and 2 show an embodiment of the present invention. In these figures, reference numeral 1 denotes a metal container, which is formed in a cylindrical shape and whose axis is oriented vertically. It has a tubular portion 101 arranged and a lid portion 102 provided so as to close the upper end of the tubular portion. The cylindrical portion 101 and the lid portion 102 may be formed integrally, or a structure in which the lid 102 is joined to the upper end of the cylindrical portion 101 by welding may be adopted. An inner flange 103 is provided at a lower end of the metal container 1, and a flange plate 3 attached to an upper end of a relatively long porcelain pipe 2 linearly extending in the vertical direction is connected to the flange 103 to seal the inside of the metal container 1. I have. The lower end of the insulator tube 2 is supported by a base (not shown) also serving as a secondary terminal box.
The metal container 1 is supported with respect to the ground potential portion via the.

1A provided at the upper end of the lid 102 is an explosion-proof plate mounting portion which breaks when the pressure in the container 1 rises excessively and releases the pressure in the container, and 1B is a lug for lifting. It is.

A metal pipe 4 whose lower end is supported by a base (not shown) is concentrically arranged in the insulator tube 2.
Is connected to a through conductor Sa of an insulating spacer S fixed to the upper surface of the flange plate 3. The insulating spacer S is attached so as not to hinder the flow of gas between the space inside the metal container 1 and the space inside the insulator tube 2.

Reference numeral 5 denotes a secondary unit. The secondary unit includes a plurality (four in the illustrated example) of ring-shaped iron cores 501.
And a secondary coil (not shown) wound around the iron core are housed in a donut-shaped shield case 502. This secondary unit is disposed inside the metal container 1 with the central axis of the iron core 501 orthogonal to the central axis of the metal container 1 and connected to the through conductor Sa of the insulating spacer S. The lead wire from the secondary coil passes through the metal pipe 4 and is connected to a secondary terminal in a secondary terminal box (not shown) provided at the lower end.

In the metal container 1, a coaxial primary conductor 8 comprising an outer primary conductor 6 and an inner primary conductor 7 is disposed so as to pass through the inside of the secondary unit 5. In order to attach the primary conductor 8 to the metal container, a pair of primary conductor attachment holes 104 and 105 are provided so as to penetrate opposite portions of the side wall of the cylindrical portion 101 of the metal container 1. These mounting holes are provided such that their respective central axes coincide with the central axis of the secondary unit 5.

The outer primary conductor 6 is formed in a tubular shape,
One end K1 and the other end L1 of the primary conductor 6
4 and 105. Outside 1
A flange 6a is welded to one end of the next conductor 6, and the flange 6a is in contact with a flange provided around the mounting hole 104 via a sealing gasket. The flange 6a is attached to the mounting hole 10 by a bolt 9.
4, one end K1 of the outer primary conductor 6 is electrically connected to the metal container 1 via a flange 6a and a bolt 9.

The other end L1 of the outer primary conductor 6 is connected to the mounting hole 1
05 is supported via a gasket on an insulating spacer 11 fixed by a bolt 10 to a flange provided at the periphery of the flange. Therefore, the outer primary conductor 6 is supported with one end electrically connected to the metal container 1 and the other end insulated from the metal container 1.

One end K1 and the other end L1 of the outer primary conductor 6 are provided so as to protrude outside the metal container 1 by a predetermined length, and one end K1 of the primary conductor 6 protruding outside the metal container 1 is provided. The first terminal fitting 12 is attached to the first terminal fitting 12. First
The terminal fitting 12 has a horizontal plate portion 12a and the horizontal plate portion 12a.
Vertical plate 1 bent downward at right angles from both ends in the width direction
2b and 12b are integrally formed, and a terminal fitting connected to the line can be connected to the horizontal plate portion 12a.

The inner primary conductor 7 is formed in a rod-like or hollow tubular shape having an outer diameter smaller than the inner diameter of the outer primary conductor 6. The inner primary conductor 7 is disposed concentrically inside the outer primary conductor 6 and has one end K2 and the other end L2 connected to one end of the outer primary conductor 6 via annular insulating spacers 13 and 14, respectively. It is supported at the other end. That is, the inner primary conductor 7 is provided in a state insulated from the outer primary conductor 6 and the metal container 1. One end K2 of the inner conductor 7 is formed flat so as to have a plate surface extending in the horizontal direction, and a second terminal fitting 15 is attached to the one end K2 by bolting or the like.

The other end L2 of the inner conductor 7 is formed flat so as to have a plate surface extending in the vertical direction, and one end of the connection conductors 16, 16 is bolted to this end L2. As shown in FIG. 2, each of the connection conductors 16 and 16 is formed of a strip-shaped conductive plate formed in an arc shape so as to surround substantially a half of the container 1, and the other ends of the connection conductors 16 and 16 are connected to the other ends. One terminal fitting 12 is bolted to the vertical plates 12b, 12b. The portions of the connection conductors 16, 16 along the outer periphery of the metal container 1 are supported by the metal container 1 via bushings 17, 17,... Provided at appropriate intervals in the circumferential direction of the container. The outer conductor 6 and the inner conductor 7 are connected in series by the connection conductors 16 and 16. In this example, a third terminal fitting 18 is attached to the other end L1 of the outer conductor 6. SF ₆ gas is sealed in the container 1 at a predetermined pressure.

In the above embodiment, for example, the first terminal fitting 12 and the second terminal fitting 15 are used as terminals on the power supply side, and the third terminal fitting 18 is used as a terminal fitting on the load side.

Now, assuming that a line (or bus) on the power supply side is connected to the first terminal fitting 12 and a line (or bus) on the load side is connected to the third terminal fitting 18, the main circuit current becomes 1st terminal fitting 12 → outer conductor 6 → third terminal fitting 1
8, the number of turns of the primary circuit is "1". If the power supply side line (or bus) is connected to the second terminal fitting 15 and the load side line (or bus) is connected to the third connection terminal fitting 18, the outer conductor 6 and the inner conductor 7 Are connected in series. At this time, the main circuit current flows through the circuit of the second terminal fitting 15 → the inner conductor 7 → the connecting conductor 16 → the outer conductor 6 → the third terminal fitting 18, so that the number of turns of the primary circuit is “2”. .

In the above embodiment, one of the first and second terminal fittings 12 and 15 is connected to the line on the power supply side, and the current transformer is switched by selecting the terminal fitting on the power supply side. One of the first and second terminal fittings may be connected to the line on the load side, and the current transformation ratio may be switched by selecting the terminal fitting on the load side.

[0022]

[Effects of the Invention] As described above, according to the present invention, the first
Connect any of the third terminal fittings to the line on the power supply side.
And choose which one to connect to the load side line
The current ratio can be switched by switching the number of turns of the primary circuit, and it is not necessary to switch the connection between the outer conductor and the inner conductor in series or in parallel. Can be easier. Also, unlike conventional double-ratio current transformers that switch between the outer conductor and the inner conductor using two types of connection fittings, there is no need to store unused connection fittings. Can be easy.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a main part of an embodiment of the present invention.

FIG. 2 is a top view of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal container 2 Insulator tube 3 Flange plate 4 Metal pipe 5 Secondary unit 6 Outer conductor 7 Inner conductor 12 First terminal fitting 15 Second terminal fitting 16 Connection conductor 18 Third terminal fitting

Claims (1)

(57) [Scope of request for utility model registration] An annular secondary unit including a metal container filled with an insulating gas, a ring-shaped iron core, and a secondary coil wound around the iron core, and disposed in the metal container; A tubular outer primary conductor provided in a state penetrating the inside of the secondary unit, both ends of which are led out of the metal container and one end of which is electrically connected to the metal container; and the outer primary conductor And an inner primary conductor disposed inside and insulated from the outer primary conductor, the double ratio current transformer being located on opposite sides of the outer primary conductor and the inner primary conductor. The ends are mutually connected by a connecting conductor provided outside the metal container, the outer primary conductor and the inner primary conductor are connected in series, and the outer primary conductor and the inner primary conductor are the same. First and second terminals at the ends located on the sides Outer 1 is provided, on the opposite side to the first and second terminal fittings
The double ratio current transformer, wherein a third terminal fitting is attached to an end of the secondary conductor and the inner primary conductor that is not directly connected to the connection conductor.