JPH08115836A - Tripple-ratio current transformer - Google Patents

Abstract

PURPOSE: To provide a current transformer which can change over a current transformation ratio on the primary side. CONSTITUTION: A primary conductor 1 for a current-transformer body is constituted of four hairpin-shaped unit primary conductors 1A to 1D, and eight terminals K1' to K4', L1' to L4' are installed at both ends of the unit primary conductors 1A to 1D. An insulating lid plate 23 which closes the upper-end opening part of a container 3 in which the current-transformer body is housed is installed. Eight lead conductors 30L1, 30L2,... are installed in a state that they are buried in, and installed at, the lid plate 23 partly, and end parts, which are situated inside the container 3, of the respective lead conductors and corresponding terminals of the primary conductor 1 are slid and brought into contact. External terminals K1,..., L1, L2,... L4 are installed at end parts, which are situated outside the container 3, of the eight lead conductors, the prescribed external terminals are connected by a connecting bar 32, and the unit primary conductors 1A to 1D are connected in series, in parallel or in serial-parallel.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a triple ratio current transformer having a triple current ratio of 1: 2: 4.

[0002]

2. Description of the Related Art A current transformer having a triple current ratio (ratio of primary rated currents) of 1: 2: 4, for example, primary rated current / secondary rated current is 100 / 5A, 200 / 5A, 400 / 5A. In the current transformer having the three types of transformation ratios, there are two methods of switching the transformation ratio. One is the switching method on the primary side and the other is the switching method on the secondary side. Since the structure of the current transformer becomes complicated, conventionally, a tap is provided in the secondary winding and the transformation ratio is switched by selecting the tap.

10 and 11 show the structure of a conventional triple-ratio current transformer. FIG. 10 is a front vertical cross-sectional view of the current transformer as viewed from the front, and FIG. 11 is the same current transformer. It is a side surface vertical cross-sectional view which carried out the vertical cross section when the container was seen from the side surface.

In FIGS. 10 and 11, reference numeral 1 denotes a primary conductor, and the primary conductor 1 has an arc-like shape in which one end is connected to a first straight line portion 1a extending linearly in the vertical direction and a lower end of the first straight line portion 1a. The folded-back portion 1b, the rising portion 1c that linearly rises upward from the other end of the folded-back portion 1b, and the slope extending obliquely upward from the upper end of the rising portion 1c so as to gradually approach the first linear portion 1a side. A portion 1d and a second straight portion 1e which is bent from the upper end of the inclined portion 1d along the first straight portion 11a and linearly extends upward to substantially the same position as the upper end of the first straight portion. And the whole has a hairpin shape. The primary conductor 1 is covered with an insulating layer made of insulating paper or the like, and a shield for improving the electric field distribution is provided on the outer peripheral portion of the insulating layer covering the first linear portion 1a and the second linear portion 1e of the primary conductor 1. The ring 2 is attached.

Reference numeral 3 denotes a current transformer container comprising a lower tank 4 made of metal and a porcelain tube 5 whose lower end is oil-tightly connected to the upper end of the lower tank 4. The pedestal 6 arranged at the bottom of the lower tank 4 is provided with the groove 7 having the inclined surfaces 7a, 7a, and the folded portion 1b at the lower end of the primary conductor 1 covered with the insulating layer is inserted into the groove 7a and inclined. It is in contact with the surfaces 7a and 7b.

The first of the primary conductors 1 covered by an insulating layer
The secondary coil unit 1 is attached to a portion of the linear portion 1a of the
0 is arranged. The secondary coil unit 10 is obtained by winding a secondary coil around a plurality of (four in the illustrated example) annular cores that are coaxially arranged, and in a state where the annular cores are linked with the primary conductor 1. It is mounted on the pedestal 6. The secondary coil unit 10 includes a coil retainer 11 arranged at an upper end thereof, a stud bolt 12 having a lower end fixed to the pedestal 6 and penetrating the coil retainer 11, and a nut 13 screwed to an upper end of the stud bolt 12. It is fixed to the pedestal 6 by. Primary conductor 1 and secondary coil unit 10
The current transformer body is composed of and.

A primary terminal 15 is provided on a side wall of the porcelain insulator 5 near the upper end thereof.
K and 15L are attached, and one end K (upper end of the first linear portion 1a) and the other end L (upper end of the second linear portion 1e) of the primary conductor 1 are connected to these primary terminals, respectively.

Insulating oil is filled in the current transformer container 3, and an oil amount adjusting device 16 is attached so as to close the upper end of the porcelain insulator 5. The oil amount adjusting device 16 includes a diaphragm that communicates with the inside of the container, and absorbs a change in volume of the insulating oil inside the container that occurs due to a temperature change.

A secondary terminal box 17 is attached to the side surface of the lower tank 4, and an oil-tight bushing 18 is attached to the side surface of the lower tank located inside the secondary terminal box. A secondary terminal 19 is provided in the secondary terminal box 17, and each tap of the secondary coil is connected to the secondary terminal 19 through a through conductor of the bushing 18.

FIG. 12 shows the electrical construction of a conventional triple-ratio current transformer, in which W1 is the primary coil and W is the primary coil.
2 is a secondary coil and C is an iron core. In the example shown in FIGS. 10 and 11, the primary coil W1 is composed of a one-turn primary conductor, and the secondary coil W2 is provided with taps T1 to T4. By selecting the taps T1 to T4, for example, three types of transformation ratios of 5/100, 5/200 and 5/400 are obtained.

[0011]

As described above, when the secondary coil is provided with a tap and the metamorphic ratio is switched on the secondary side, the tap changes the ampere-turn linked to the iron core. A tap with a small current ratio has a problem that the transformation error becomes large and the current detection accuracy deteriorates. It is conceivable to increase the iron core around which the secondary coil is wound in order to reduce the transformation error. However, in that case, the iron core becomes so large that the current transformer becomes large in size and the cost becomes unavoidable.

Therefore, the primary conductor is constituted by four unit primary conductors, and a terminal board having a total of eight external terminals for switching connection corresponding to the terminals at both ends of these four unit primary conductors is provided. By connecting both ends of each unit primary conductor to the corresponding external terminals through the eight lead conductors in the upper space of the current transformer container, and connecting the predetermined external terminals of the terminal board with connection bars, 4 Switch the connecting conductors in series, parallel, or series-parallel to 1: 2:
It is conceivable to obtain a current ratio of 4. For example, in a triple-ratio current transformer having a primary / secondary rated current of 100-200-400 / 5A, the primary rated current is 100A and the ratio is 5/100.
4 unit primary conductors are connected in series in order to obtain a transformation ratio of, and two unit primary conductors connected in parallel are taken in order to obtain a transformation ratio of 5/200 with a primary rated current of 200A. As a set of parallel unit conductors, two sets of parallel unit primary conductors are connected in series. Further, when the primary rated current is 400 A and a transformation ratio of 5/400 is obtained, four unit primary conductors are connected in parallel.

With this configuration, the transformation ratio can be switched without changing the ampere-turns linked to the iron core.
However, when the primary conductor is composed of four unit primary conductors, the space between the four unit primary conductors and the eight external terminals provided on the terminal board is 8 in the upper space in the current transformer container.
If the connection is made via two lead conductors, the eight lead conductors will be complicated in the upper space of the current transformer container, and the connection structure between the primary conductor and the terminal board will be remarkably complicated. It is unavoidable that the assembly of the sink is troublesome.

Further, in this case, since the lead-out conductor is arranged so as to float in the upper space in the current transformer container, when the overcurrent flows through the lead-out conductor to the primary conductor, the lead-out conductor is subjected to electromagnetic mechanical force. There is a risk that it will move and be deformed.

For these reasons, in the conventional triple-ratio current transformer, the transformation ratio is exclusively switched on the secondary side.

An object of the present invention is to configure the primary conductor with four unit primary conductors so that the transformation ratio can be switched on the primary side without changing the ampere-turns interlinking with the iron core. It is an object of the present invention to provide a triple-ratio current transformer whose assembly is simplified by making it possible to easily connect the primary conductor composed of four unit primary conductors and the external terminal for switching connection.

Another object of the present invention is that a lead conductor connecting between a primary conductor composed of four unit primary conductors and an external terminal for switching connection may be deformed by an electromagnetic mechanical force when an overcurrent is applied. It is to provide the lost triple ratio current transformer.

[0018]

According to the present invention, a hairpin-shaped first to fourth unit primary conductor having a folded portion at a lower end thereof is provided, and the first to fourth unit primary conductors are insulated from each other. And a current transformer main body having a primary conductor having a structure arranged side by side so as to have a hairpin shape as a whole, and a secondary coil wound around an iron core arranged so as to interlink with the primary conductor. A triple-ratio current transformer in which a folded-back portion of the primary conductor is located in the lower end and is housed in a container filled with insulating oil, and a triple current ratio is obtained by switching and connecting the first to fourth unit primary conductors. It is related to vessels.

In the present invention, the K1 'to K4' terminals are provided at one end of each of the first to fourth unit primary conductors, and the L1 'to L4' terminals are provided at the other ends thereof, and these eight terminals are connected to the primary conductors. Place them side by side on the top edge of.

A pair of primary terminals are attached to the side wall portion of the upper end of the container, and one and the other of the pair of primary terminals are respectively connected to the first terminal.
Connected to one end of the unit primary conductor and the other end of the fourth unit primary conductor.

Further, an insulating cover plate for closing the opening provided at the upper end of the container is provided, and the eight terminals K1 'to K4' and L1 'to L4' of the primary conductor are provided in a state of penetrating the cover plate. Each of the corresponding eight lead conductors is supported.

One end of the eight lead conductors located inside the container and the corresponding terminal of the primary conductor are formed so as to be in sliding contact with each other along the axial direction of the container, and the lid plate is attached to the upper end of the container. In this case, one end of each lead conductor is automatically connected to the corresponding terminal of the primary conductor.

As the conductive material forming the lead conductor,
At least a material having rigidity enough to withstand the force acting on the lead conductor during the sliding contact is used.

Here, having rigidity means having a property of withstanding bending or twisting (it hardly deforms when a bending force or a twisting force is applied). The rigidity of the conductive material forming the lead conductor naturally increases as the cross-sectional area increases, but the lead conductor used in the present invention does not have to be a "rigid body" in the strict sense, and it does not have to be a terminal of the primary conductor. It is sufficient that the rigidity is such that sliding contact is not hindered. As the lead conductor, for example, a solid rod-shaped conductor made of a material having both conductivity such as copper or aluminum and having a predetermined cross-sectional area can be used.

The other ends of the eight lead conductors, which are located outside the container, are provided with external terminals for switching connection corresponding to the terminals K1 'to K4' and L1 'to L4' of the primary conductor, respectively, K1 to K4 and L1.
.About.L4, and the external terminals are arranged in a predetermined pattern on the cover plate. Each external terminal is formed so that a connection bar for electrically connecting a predetermined lead conductor can be detachably attached.

In the present invention, the external terminals K1 to K4 and L1 to L4 are preferably arranged in the following specific pattern.

That is, among the external terminals K1 to K4, K2 and K
3 and K4 are arranged side by side on the first straight line at equal intervals d, and among the external terminals L1 to L4, L1, L2 and L4 are arranged.
3 is an external terminal K2 on a second straight line extending in parallel with the first straight line at a position separated from the first straight line by a distance equal to the distance d.
, K3 and K4. The external terminal K1 is located outside the area where the external terminals K2 to K4 and L1 to L3 are provided, and the external terminals K2 and L1.
It is placed at a position such that the distance between and is equal to the distance d. Further, the external terminal L4 is the external terminals K2 to K4 and L1.
.About.L3 are located outside the region where they are provided, and at a position where the distances between the external terminals K4 and L3 are both equal to the distance d.

In this case, each connection bar is formed in a plate shape, and each external terminal is constructed so that a plurality of connection bars can be attached in a stacked state.

[0029]

As described above, the insulating cover plate for closing the opening at the upper end of the container is provided, and the eight terminals K1 'to K4' and L1 'to L4' of the primary conductor are provided in a state of penetrating the cover plate. 8 lead conductors respectively corresponding to the above, and one end of the 8 lead conductors located in the container and the corresponding terminal of the primary conductor are formed so as to be in sliding contact with each other, and the lid plate is attached to the container. When one end of each lead-out conductor is automatically connected to the corresponding terminal of the primary conductor when attached to the upper end, it is possible to easily pull out the external terminal from the primary conductor.
The assembly of the current transformer can be simplified.

As described above, the eight lead conductors that lead out the eight terminals of the primary conductor to the outside are formed of a material having rigidity, and the lead conductors are supported so as to penetrate the cover plate. Then, since the output conductor can be firmly supported by the lid plate, it is possible to prevent the output conductor from being moved and deformed by the electromagnetic mechanical force when an overcurrent flows, and the current transformer having high strength against the overcurrent. Can be obtained.

Further, when the external terminals are arranged in the specific pattern as described above, the distances between the external terminals connected to each other via the connection bar are all equal to obtain a triple current ratio of 1: 2: 4. Therefore, it suffices to prepare a predetermined number of one type of connection bar, and it is possible to connect predetermined external terminals without selecting the connection bar, so that the work for switching the current ratio can be simplified.

If a plurality of connection bars can be attached to each external terminal in a stacked state, when there is a connection bar that is not used, the connection bar that is not used is stacked with another connection bar. Since it can be connected, there is no risk of the connection bar being lost.

[0033]

1 to 5 show the structure of an essential part of an embodiment of the present invention, and FIG. 1 (A) is a vertical cross-sectional view of an upper portion of a current transformer of the embodiment as seen from the front. FIG. 2B is a plan view of the current transformer of the embodiment with the cover plate removed, FIG.
3 and 4 are a plan view, a partially sectional front view and a bottom view of the cover plate used in the embodiment. FIG. 5 is an explanatory diagram showing an arrangement of terminals at the upper end of the primary conductor.

In the primary conductor 1 used in the present invention, the hairpin-shaped first to fourth unit primary conductors 1A to 1D having a folded portion at the lower end are arranged so as to be insulated from each other and to have a hairpin-like shape as a whole. It has an arranged structure.
In FIG. 1B, the first to fourth unit primary conductors 1A to
The top of the 1D is shown. Each of the first to fourth unit primary conductors is covered with an insulating layer made of insulating paper or the like, and is also covered with an insulating layer while being attached to the outer peripheral surface of the first unit primary conductor 1A covered with the insulating layer. The formed second unit primary conductor 1B is arranged. Also the second
A third unit primary conductor 1C covered with an insulating layer is arranged in a state of being attached to one side surface of the unit primary conductor 1B of
A fourth unit primary conductor 1D covered with an insulating layer is arranged along the inner circumference of the third unit primary conductor 1C.

As shown in FIG. 1B, terminals K1 'to K4' are respectively provided at one ends of the first to fourth unit primary conductors.
And terminals L1 'to L4' are respectively provided at the other ends of the first to fourth unit primary conductors. These eight terminals in total are arranged in two rows on the upper end of the primary conductor 1.

The terminals K1 'to K4' and L1 'to L4' at both ends of the first to fourth unit primary conductors have holes h opened at the end faces of one end and the other end of the unit primary conductors 1A to 1D, respectively. The hole h constitutes a female sliding contact.

The overall shape of the primary conductor 1 formed by arranging the first to fourth unit primary conductors side by side is shown in FIGS.
The shape of the primary conductor used in the conventional current transformer shown in FIG. 1 is almost the same, and the primary conductor 1 is formed in the lower part of the primary conductor 1 like the current transformer shown in FIGS. 10 and 11. A secondary coil unit formed by winding a secondary coil around an interlocking annular core is attached. A current transformer main body is constituted by the primary conductor 1 and the secondary coil unit, and the current transformer main body is housed in a current transformer container 3 including a lower tank and an insulator pipe 5.

A pair of primary terminals 15K and 1 in a state where the side wall portion at the upper end of the porcelain insulator 5 constituting the current transformer container 3 is oil-tightly penetrated.
5L is attached. Pair of primary terminals 15K and 15
The ends of the L located inside the container are respectively the terminal K1 'at one end of the first unit primary conductor 1A and the fourth unit primary conductor 1D.
Is connected to the terminal L4 'at the other end via the conductors 20K and 20L, respectively. Terminal plates 21K and 21L are attached to the outer ends of the primary terminals 15K and 15L.

A lid plate fixing metal fitting 22 having a flange 22a is fixed to the upper end of the porcelain bushing 5 constituting the container 3 by cement, and an insulating lid plate for closing the upper end of the container 3 on the lid plate fixing metal fitting. 23 are arranged. The cover plate 23 is made of a resin molded product, and has a truncated cone-shaped cover plate body 23a.
And a flange portion 23b, and a large number of mounting holes 23c are provided in the flange portion 23b. The cover plate 23 is
It is fastened to the fixing bracket 22 by a bolt 24 penetrating the flange 22a and the mounting hole 23c of the fixing bracket 22 and a nut 25 screwed into the bolt 24.

In this embodiment, the L-shaped metal fitting 26 arranged on the upper surface of the lid plate 23 is fastened together with the nut 25, and the outer shell case 16A of the oil amount adjusting device 16 is bolted to the L-shaped metal fitting 26. . The oil amount adjusting device 16 is provided with a diaphragm 16B that is deformed according to a change in volume of insulating oil filled in the container 3, and the diaphragm 16B penetrates a hole 23d provided in the cover plate 23 in an oiltight manner. It is made to communicate with the inside of the container 3 through the pipe 16C provided so as to be.

Eight terminals K1 'to K4' and L of the primary conductor 1
Eight lead conductors 30K1 for 1'-L4 'respectively
30K4 and 30L1 to 30L4 are supported in a state of penetrating the cover plate main body 25a (a state in which a part is embedded in the cover plate).

Eight lead conductors 30K1 to 30K4 and 30
One ends of the L1 to 30L4 located in the container are machined to form male sliding contacts 30K1 'to 30K4' and 30L1 'to 30L4', respectively. These sliding contacts are the terminals K1 'to K at the upper ends of the unit primary conductors 1A to 1D, respectively.
The female contacts provided on 3'and L1 'to L4' are slidably contacted from the axial direction of the container 3, and when the lid plate 25 is attached to the upper end of the container 3, One end is automatically connected to the corresponding terminal of the primary conductor.

The lead conductors 30K1 to 30K4 and 30L1
-30L4 is formed by molding a solid rod made of copper or aluminum, and at least when sliding contact with the terminals K1'-K3 'and L1'-L4' of the unit primary conductors 1A-1D. The respective cross-sectional areas are set so as to have rigidity enough to withstand the force acting on the lead conductor.

Eight lead conductors 30K1 to 30K4 and 30
The other ends of the L1 to 30L4 located outside the container are external terminals K1 to K4 and L1 to L4 for switching connection respectively corresponding to the terminals K1 'to K4' and L1 'to L4' of the primary conductor.
These external terminals are arranged in a predetermined pattern on the upper surface of the cover plate 23, as shown in FIG.

The external terminals K1 to K4 and L1 to L4 are formed so as to have the same outer diameter, and external threads are provided on their outer circumferences, and nuts 31 are screwed into the external threads. . The connection bar 32 for electrically connecting the predetermined lead conductors can be detachably attached by the male screw portions of the external terminals K1 to K4 and L1 to L4 and the nuts 31 screwed to the male screw portions. Has become.

In order to facilitate the connection between the lead conductors by the connecting bar 32, in this embodiment, the external terminals K1 to K4 and L1 to L4 are arranged in a specific pattern as shown in FIG. That is, among the external terminals K1 to K4, K2, K
3 and K4 are arranged side by side with a distance d equal to O1 -O1 on the first straight line, and among the external terminals L1 to L4, L1
, L2 and L3 are aligned with the external terminals K2, K3 and K4 on a second straight line O2 -O2 extending in parallel with the first straight line at a distance equal to the distance d from the first straight line O1 -O1. They are arranged side by side in a state. In addition, external terminal K
1 is arranged outside the region where the external terminals K2 to K4 and L1 to L3 are provided and at a position where the distance between the external terminals K2 and L1 is equal to the distance d, and the external terminal L4 is an external terminal. It is arranged outside the region where K2 to K4 and L1 to L3 are provided, and at a position where the distance between the external terminals K4 and L3 is equal to the distance d.

In this embodiment, a total of 6 connecting bars 32 are prepared, and all connecting bars 32 are formed to have the same shape and the same size. As shown in FIG. 6, each connection bar 32 is formed in the shape of a strip plate, and a pair of holes 32a, 32a into which the external terminals K1 to K4 and L1 to L4 are fitted are formed at both ends of the connection bar 32 at the interval d. Between any external terminals provided at equal intervals, by fitting a predetermined external terminal into each hole 32a and screwing the nut 31 into the male screw portion of the external terminal, the external terminals are arranged at a distance d. The connection bar 32 can be mounted over the bridge.

The external terminals K1 to K4 and L1 to L4 are set to have respective lengths so that a plurality of connecting bars 32 can be mounted in a superposed state, and it is necessary to use one of the six connecting bars. If there is a connection bar that does not have a connector, the connection bar that does not need to be used can be arranged in a state of being superposed with any other connection bar that connects predetermined external terminals. The other points are the same as those of the conventional current transformer shown in FIGS. 11 and 12.

In the above current transformer, the oil amount adjusting device 1
6, a predetermined current ratio can be obtained by connecting predetermined external terminals with the connection bar 32, and by selecting an external terminal to which the connection bar is attached, it becomes 1:
Switching of a triple current ratio of 2: 4 can be performed.

For example, the primary / secondary rated current is 100-20.
If it is 0-400 / 5A, the primary rated current is 10
To obtain a 5/100 transformation ratio as 0 A,
As shown in (A), between external terminals K2 and L1, K3 and L
3 connecting bars 32 between 2 and between K4 and L3
And the first to the fourth as shown in FIG.
The unit primary conductors 1A to 1D are connected in series. In this case, the three unused connection bars are external terminals K2 and L1.
, K3 and L2, and K4 and L3, respectively.

Further, assuming that the primary rated current is 200 A, it is 5/2.
To obtain a transformation ratio of 00, as shown in FIG. 8A, the external terminals K1 and K2, L1 and L2, L2 and K3 are connected.
, K3, K4, and L3, L4 are connected by five connecting bars 32, respectively, so that the first and second unit primary conductors 1A and 1B are connected as shown in FIG.
A set of parallel unit conductors connected in parallel, and a third and a fourth
In this case, a total of two sets of parallel unit conductors including one set of parallel unit conductors in which the unit primary conductors 1C and 1D of FIG. Not used in this case 1
One connection bar is overlaid on one of the connection bars connecting the external terminals.

Further, assuming that the primary rated current is 400 A, 5 /
To obtain a transformation ratio of 400, as shown in FIG. 9 (A), the external terminals K1, K2, K2, K3, K3, K4 are connected.
, L1 and L2, L2 and L3, and L3 and L4 are connected by six connecting bars 32, respectively, and four unit primary conductors 1A to 1D are connected in parallel as shown in FIG. Connecting.

As described above, if the current ratio is switched by switching and connecting the unit primary conductors 1A to 1D, the transformation ratio can be switched without changing the ampere-turns linked to the iron core. It is possible to prevent the error from increasing.

As described above, the eight conductors 30K1 to 30K4 and 30L1 to 30L4 are supported while the insulating cover plate 23 for closing the opening at the upper end of the container is penetrated, and the conductors 30K1 to 30K4 are also arranged. And 30L1 to 30L4, one end of which is located in the container and the corresponding terminal of the primary conductor are formed so as to be in sliding contact with each other, and when the lid plate 23 is attached to the upper end of the container, the lead conductors 30K1 to 30K4 and 30L1
If one end of ~ 30L4 is connected to the corresponding terminals K1'-K4 'and L1'-L4' of the primary conductor, the output conductor will not be complicated in the upper space in the container, so that the output conductor Since the lead-out structure can be simplified and the lead conductor and the terminal at the upper end of the unit primary conductor can be automatically connected, the current transformer can be easily assembled.

As described above, the eight terminals K1 'of the primary conductor
8K to 30K1 to 30K4 and 30L1 to 30L4 for drawing out K4 'and L1' to L4 'to the outside, respectively, are formed of a material having rigidity, and a part of the lead conductor is molded in the lid plate 23. Since the output conductors 30K1 to 30K4 and 30L1 to 30L4 can be firmly supported by the cover plate when supported in a state, the output conductor is prevented from moving and deforming due to electromagnetic mechanical force when an overcurrent flows. Therefore, it is possible to obtain a current transformer having high strength against overcurrent.

When the external terminals K1 to K4 and L1 to L4 are arranged in a specific pattern as shown in FIG.
In order to obtain a triple current ratio of 2: 4, the distances between the external terminals connected to each other via the connection bar 32 are all equal, so if one type of connection bar is prepared in a predetermined number (6). Good. In this case, since it is possible to connect the predetermined external terminals without selecting the connection bar, it is possible to simplify the work when switching the current ratio.

If a plurality of connection bars can be attached to each external terminal in a stacked state, when there is a connection bar that is not used, the connection bar that is not used is stacked with another connection bar. Since it can be stored, the risk of the connection bar being lost can be eliminated.

[0058]

As described above, according to the present invention, the insulating lid plate for closing the opening at the upper end of the container is provided, and the eight terminals K1 'of the primary conductor are provided in a state of penetrating the lid plate. K4 'and L1'
Support eight lead conductors corresponding to ~ L4 ',
One end of the eight lead conductors located in the container and the corresponding terminals of the primary conductor are formed so as to be in sliding contact with each other,
If one end of each lead-out conductor is automatically connected to the corresponding terminal of the primary conductor when the lid plate is attached to the upper end of the container, it is possible to easily pull out the external terminal from the primary conductor. Therefore, there is an advantage that the assembly of the current transformer can be simplified.

Further, according to the present invention, the eight lead conductors for respectively drawing the eight terminals of the primary conductor to the outside are formed of a material having a rigidity sufficient to withstand sliding contact with at least the terminals of the primary conductor. Then, if the lead conductor is supported while penetrating the lid plate, the lead conductor can be firmly supported by the lid plate, so that when the overcurrent flows, the lead conductor moves and is deformed by the electromagnetic mechanical force. Therefore, it is possible to obtain a current transformer having high strength against overcurrent.

Further, according to the invention described in claim 2,
One type of connection bar was prepared because the external terminals were arranged in a specific pattern and the distances between the external terminals that were connected to each other via the connection bar were made equal in order to obtain a triple current ratio of 1: 2: 4. The cost can be reduced as well. Further, since it is possible to connect the predetermined external terminals without selecting the connection bar, it is possible to simplify the work for switching the current ratio.

Further, according to the invention described in claim 2, since a plurality of connection bars can be attached to each external terminal in a state of being overlapped with each other, when there is a connection bar which is not used, the connection bar which is not used is connected. There is an advantage that the bar can be connected to the other connection bar in an overlapping manner and the risk of the connection bar being lost can be eliminated.

[Brief description of drawings]

FIG. 1 (A) is a vertical cross-sectional view of an upper portion of the current transformer of the embodiment as seen from the front, and FIG. 1 (B) is a plan view of the current transformer of the embodiment with a cover plate removed. It is a figure.

FIG. 2 is a plan view of a lid plate used in the embodiment.

FIG. 3 is a front view showing a cross section of a part of a lid plate used in the embodiment.

FIG. 4 is a bottom view of a cover plate used in the same embodiment.

FIG. 5 is an explanatory diagram showing an arrangement of terminals at the upper end and an arrangement of terminals at the lower end of the lead conductor used in the embodiment.

FIG. 6 is a front view of a connection bar used in an embodiment of the present invention.

FIG. 7A is an explanatory view showing the arrangement of connection bars when the first to fourth unit primary conductors are connected in series in the embodiment of the present invention. (B) is a connection diagram showing the electrical configuration of the primary conductor when the connection bar is arranged as in (A).

FIG. 8A is an explanatory view showing an arrangement of connection bars when the first to fourth unit primary conductors are connected in series and parallel. (B) is a connection diagram showing the electrical configuration of the primary conductor when the connection bar is arranged as in (A).

FIG. 9A is an explanatory diagram showing the arrangement of connection bars when the first to fourth unit primary conductors are connected in parallel.
(B) is a connection diagram showing the electrical configuration of the primary conductor when the connection bar is arranged as in (A).

FIG. 10 is a front vertical cross-sectional view in which a conventional current transformer is viewed in a vertical cross section.

FIG. 11 is a side surface vertical cross-sectional view of a conventional current transformer in a vertical cross-section when viewed from the side.

FIG. 12 is a circuit diagram showing an electrical configuration of a conventional current transformer.

[Explanation of symbols]

 1 Primary conductor 1A to 1D Unit primary conductor 2 Secondary coil unit 3 Current transformer container, 15L, 15K Primary terminal 23 Lid plate 30K1 to 30K4, 30L1 to 30L4 Lead conductor K1 'to K4', L1 'to L4' Primary conductor Terminals K1 to K4, L1 to L4 external terminals

Claims (2)

[Claims] 1. A hairpin-shaped first to fourth unit primary conductor having a folded-back portion at a lower end thereof is provided, and the first to fourth unit primary conductors are insulated from each other and have a hairpin shape as a whole. A current transformer body having a primary conductor having a structure arranged side by side as described above, and a secondary coil wound around an iron core arranged so as to interlink with the primary conductor, with a folded portion of the primary conductor at the lower end. A triple-ratio current transformer, which is housed in a container filled with insulating oil in a state of being positioned and obtains a triple current ratio by switching and connecting the first to fourth unit primary conductors, To K at one end of the fourth unit primary conductor
1'-K4 'terminals and L1'-L4' terminals are provided at the other ends, respectively, and these eight terminals are arranged side by side on the upper end of the primary conductor. Terminals are attached and one and the other of the primary terminals of the pair are respectively first
Of the unit primary conductor and the other end of the fourth unit primary conductor, respectively, and an insulating cover plate for closing the opening provided at the upper end of the container is provided and penetrates the cover plate. Eight lead conductors respectively corresponding to the eight terminals K1 'to K4' and L1 'to L4' of the primary conductor are supported, and one end of the eight lead conductors located in the container and the primary conductor Corresponding terminals are formed so as to be in sliding contact with each other along the axial direction of the container, and when the cover plate is attached to the upper end of the container, one end of each lead conductor becomes a corresponding terminal of the primary conductor. The lead conductors are made of a conductive material that is rigid enough to withstand a force acting on the lead conductors at least during the sliding contact, and the lead conductors are connected to the outside of the container. The other end located at External terminals K1 to K4 and L1 to L4 for switching connection respectively corresponding to the children K1 'to K4' and L1 'to L4', which are arranged in a predetermined pattern on the cover plate. The triple ratio current transformer, wherein the external terminal is formed so that a connection bar for electrically connecting predetermined lead conductors can be detachably attached. 2. Of the external terminals K1 to K4, K2, K
3 and K4 are arranged side by side on the first straight line at an equal distance d, and among the external terminals L1 to L4, L1, L2 and L3 are located at a distance equal to the distance d from the first straight line. The external terminal K on the second straight line extending parallel to the first straight line.
2, K3 and K4 are arranged side by side, and the external terminal K1 is connected to the external terminals K2 to K4 and L1 to
Outside the area where L3 is provided and at the external terminal K
2 and L1 are arranged at positions such that the distance between them is equal to the distance d, and the external terminal L4 is the external terminals K2 to K4 and L1 to
Outside the area where L3 is provided and at the external terminal K
4 and L3 are arranged at a position where the distance between them is equal to the distance d, each connection bar is formed in a plate shape, and each external terminal can be attached with a plurality of connection bars stacked. The triple ratio current transformer according to claim 1, wherein the triple ratio current transformer is formed so that it can be formed.