JPH0347566B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention particularly relates to a current detection device in which a primary conductor in which a current transformer is installed is improved.

[Background of the invention]

Generally, current transformers used in closed switchboards are used for relays that detect the current flowing through the conductor on the load side and trip the circuit breakers, and for current transformers that constantly measure the current and monitor the ammeter. There is. When installing these current transformers on a power distribution board, for example,
As shown in Figure 1 of the publication, two current transformers are installed in series on the load-side conductor.

On the other hand, the current range of a current transformer is generally determined by the rated ratio of the primary current value and the secondary current value. For example, when measuring a current of 300/5A or more, a feedthrough current transformer is used. Below 300/5A, for example, from 200/5A to 5/5A, a feed-through current transformer will not have enough ampere turns, so a larger one is used where the primary conductor and secondary conductor are wound around the iron core and covered with an insulating material. Using a wire-wound current transformer,
The current range has been expanded. When these current transformers are installed in a switchboard, the arrangement is exactly the same as described above. Furthermore, if a current transformer for internal protection of the transformer is added, or a wire-wound current transformer is added to the relay current transformer and measurement current transformer, three units will be installed in series. In this case, the depth dimension of the switchboard becomes wider. In addition, two types of current transformers, such as a through-type current transformer and a wire-wound type current transformer, are required, making manufacturing and management difficult and uneconomical.

[Purpose of the invention]

An object of the present invention is to provide an economical current detection device with a reduced installation area.

[Summary of the invention]

In the current detection device of the present invention, if the primary conductor is wound in one or more turns to form at least two locations with different ampere turns, and a current transformer is installed at these locations, only one type of current transformer is sufficient for current detection. In addition to widening the detection range, the current transformer is easy to assemble and manage, making it economical.

[Embodiments of the invention]

Embodiments of the present invention will be described below using the current detection device 1 shown in FIGS. 1 and 2.

The primary conductor 2 is wound to form one turn, and is coated with an insulating material such as epoxy resin to form an insulating annular portion 3 made of an insulating layer. The insulating annular portion 3 extends downward and is supported by the support legs 4. A first current transformer 5 and a second current transformer 6 are attached to the upper and lower sides of the insulating annular portion in correspondence with each other.
Since the structures of the current transformers 5 and 6 are exactly the same, the structure of the first current transformer 5 will be explained with reference to FIG.

In the first current transformer 5, an iron core 7 is fitted into an insulating annular portion 3, and a secondary winding 8 is wound around the upper part of the split iron core 7. In this assembly method, a pair of U-shaped core legs 9 are formed by bending a plurality of silicon steel plates into a U-shape, and a secondary winding 8 is attached to one side of one of the U-shaped core legs 9.
is attached, and with the other side inserted into the insulating ring part 3, the pair of U-shaped core legs are brought into contact with each other, and then the tightening band 10 is wound around the outside of the U-shaped core leg 9, and the tightening band is The first current transformer 5 is completed by tightening the receiving metal fittings 11 bent at both ends with bolt/nut tightening means 12. A wedge 9 is provided between the insulating annular portion 3 and the U-shaped core leg 9.
Inserting A.

The primary conductor 2 in the insulated annular part equipped with the first current transformer 5 and the second current transformer 6 has a first turn part 13 in which the primary conductor is wound one turn, and a half part from the first turn part 13. A second turn portion 14 is formed by winding a large number of turns. First turn part 13
is equipped with a first current transformer 5, and the second turn portion 14 is equipped with a second current transformer 6, respectively.

With this configuration, if a current is passed through the primary conductor 2, the first
Since current also flows through the turn portion 13 and the second turn portion 14, more magnetic flux is generated in the second turn portion 14 than in the first turn portion 13. For this reason, the second
The ampere turn of the turn part 14 is the first turn part 1
3, the first and second current transformers 5, 6 of the same type are connected to the first and second turn parts 13, 14.
Even if the second current transformer 6 is installed in a wire-wound type, the second current transformer 6 can be used in the same way as a wire-wound type. Therefore, since it is possible to measure from a small current range to a large current range with one type of current transformers 5 and 6, it is only necessary to manufacture one type of current transformer, which is easy and economical to manufacture and manage.

In this embodiment, the case where the ampere turns are changed will be explained. 4 and 5 show cases in which the primary conductor 2 is wound once and twice to form the first turn portion 13 on the ring-shaped portion and the second turn portion 14 on the output terminal 20, respectively. . The pair of output terminals 20 may be arranged with their heights shifted from each other. Figure 6 shows the primary conductor 2 twice and 3 times.
By winding it around to form three turn portions 21, 22, and 23 having different ampere turns, and installing a current transformer 24, various current detection ranges can be obtained. That is, by increasing or decreasing the number of turns of the primary conductor, a desired current measurement range can be obtained with one type of current transformer.

In this embodiment, the primary conductor 2 is formed in the insulating annular portion 3 to increase the cooling area in contact with the outside air and improve cooling, so that the size can be reduced accordingly. The shape of the above-described insulating annular portion 3 may be any shape other than a circular shape, such as a triangular shape, a square shape, a U-shape, etc., as long as a plurality of current transformers can be installed therein.

In this embodiment, the first current transformer 5 and the second current transformer 6 are arranged correspondingly in the insulating ring part 3, so two current transformers can be installed without increasing the installation area. I can do it. Also, if we consider current transformers 5 and 6, we will see that in conventional current transformers, the primary conductor and primary or secondary winding are placed outside the core and then covered with an insulating layer. In the present invention, the insulating annular portion 3 is formed by covering the primary conductor 2 with an insulating layer. Since the insulating annular portion 3 is arranged on the inner diameter side of the annular core 9, the thickness and diameter of the insulating layer of the insulating annular portion 3 are the same as those of a conventional current transformer. In addition, the current transformers 5 and 6 can be made much lighter in weight and outer dimensions than those of conventional current transformers, as well as being smaller in size.

Furthermore, since the annular core 9 is in direct contact with the outside air, cooling is good and the core can be made smaller accordingly. Since the secondary winding 8 is arranged outside the annular core 9, there is an advantage that maintenance and inspection can be easily performed without any interference.

In FIG. 7, the insulating annular portion 3 is made separable so that undivided integral molded through-type current transformers 5' and 6' can be inserted into the insulating annular portion 3.

[Effects of the Invention] As described above, the current detection device of the present invention can now detect from a small current to a large current using the same type of current transformer.
Economical.

[Brief explanation of drawings]

FIG. 1 is a side sectional view of a current detection device shown as an embodiment of the present invention, FIG. 2 is a side view of FIG. 1, and FIG.
The figure is a side cross-sectional view of the first current transformer in FIG. 1, FIGS. 4 to 6 are schematic explanatory diagrams of current detection devices shown as other embodiments of the present invention, and FIG. 7 is a side sectional view of the first current transformer in FIG. FIG. 2 is a perspective view of the current detection device according to the embodiment. 2...Primary conductor, 3...Insulating ring part, 5, 6...
...Current transformer, 14...First turn part, 15...Second
Turn part.

Claims (1)

[Claims] 1. In a device for detecting the current flowing through the primary conductor by installing a plurality of current detectors with different current side predetermined ranges on the primary conductor, the primary conductor having a different number of turns is inserted into each current detector. A current detection device characterized by: 2. In a device that detects the current flowing through the primary conductor by installing a plurality of current detectors with different current side fixed ranges on the primary conductor, the primary conductor with different numbers of turns is covered with an insulating ring part and the primary conductor with different numbers of turns is A current detection device comprising: a plurality of annular cores attached to different insulating annular portions; and a secondary winding attached to the outside of the annular core.