JPH0992124A - Circuit breaker provided with current transformer, and power distribution monitoring equipment provided with same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decrease working manhours in installation of a monitoring device for monitoring a current flowing through a main circuit of an existing distribution panel. SOLUTION: A device is provided with a breaker 10 and a current transformer 20. The current transformer 20 is fixed to be incapable of relatively moving to the breaker 10 under the condition where a load side terminal 14 of the breaker 10 is being inserted into a through hole 22 of the current transformer 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit breaker installed on a switchboard or a distribution board, and more particularly to a circuit breaker suitable for monitoring a current flowing through the circuit breaker, and a switchboard equipped with the circuit breaker. Regarding monitoring equipment.

[0002]

2. Description of the Related Art Usually, a plurality of circuit breakers are provided on a switchboard, a distribution board, or the like. In the case of monitoring the current flowing through the main circuit of the switchboard or the like, conventionally, as shown in FIG. 8, the current transformers 3, 3 are attached to the main cables 2, 2 connected to the circuit breaker 1, and The outputs from the current transformers 3 are input to the distribution monitoring device 50.

[0003]

However, in such a conventional technique, when trying to monitor the current flowing through the main circuit of the existing switchboard, the main cables 2, 2 in the switchboard are to be monitored.
In addition, the current transformers 3 and 3 have to be newly attached, which is a problem that a great number of man-hours are required.

Specifically, the main cables 2 ', 2'connected to the circuit breaker 1 are temporarily disconnected, and the current transformers 3, 3 attached to the main cables 2', 2'are properly installed in a switchboard. Main cables 2 ', 2'remove so that they can be placed in the gap
It is necessary to bend the cable, prepare a new main cable, and bend it. When the bending work of the main cables 2 and 2 is completed, the current transformers 3 are connected to the main cables 2 and 2.
3 must be installed and the main cables 2, 2 must be connected to the circuit breaker 1 again. Further, it is also necessary to fix the current transformers 3 and 3 attached to the main cables 2 and 2 to a power distribution board or the like so as not to move. Also, if there is no suitable gap for disposing the current transformers 3 in the switchboard, the power distribution board must be replaced with a larger one. Particularly, in the prior art, the current transformer 3 is connected to the main cable 2
In order to attach the current transformer 3, a current transformer whose through-hole has an inner diameter larger than the outer diameter of the main cable 3 is used, and as a result, a current transformer having a capacity larger than necessary is used. It is very likely that you will have to prepare a new large power distribution board.
In fact, in the prior art, a current transformer of 15 VA or more whose secondary side rated load is unnecessarily large is used.

The present invention has been made by paying attention to such a conventional problem, and significantly reduces the number of working steps when installing a distribution monitoring device for monitoring a current flowing in a main circuit in a distribution board or the like. It is an object of the present invention to provide a circuit breaker with a current transformer that can be used, and a distribution monitoring facility including the circuit breaker.

[0006]

A circuit breaker with a current transformer for achieving the above-mentioned object has a power source side terminal and a load side terminal, and supplies a current flowing from the power source side terminal to the load side terminal. A current transformer having a main body having a through hole formed therein and having a through hole formed therein, the current transformer outputting an amount of current proportional to the amount of current flowing through the conductor passed through the through hole; The vessel is
One of the power source side terminal and the load side terminal of the circuit breaker is inserted into the through hole of the current transformer and is fixed so as not to move relative to the circuit breaker. It is what

Here, in the circuit breaker with a current transformer, there are a plurality of terminals on the power source side, and the plurality of terminals on the power source side are arranged in a constant direction at a constant interval L from each other. The width in the constant direction is a constant width a, a plurality of the load side terminals, a plurality of the load side terminals are arranged in the constant direction at the constant interval L, the load side terminal of the When the width in the constant direction is the constant width a, the main body of the current transformer, the width in the constant direction when the current transformer is attached to either the power supply side terminal or the load side terminal,
It is necessary to be formed to be equal to or less than a value obtained by subtracting the constant terminal width a from a value obtained by doubling the constant terminal interval L.

Further, the distribution monitoring equipment for achieving the above-mentioned object, the circuit breaker with the current transformer and the output from the current breaker of the circuit breaker with the current transformer are input, A monitoring device for monitoring the current flowing through the circuit breaker of the circuit breaker with a current transformer.

[0009] By the way, in order to save the space of the switchboard, the secondary side rated load of the above current transformer is the length of the cable electrically connecting the monitoring device and the current transformer. It is preferable to use a current transformer whose load is less than the rated load on the secondary side, which is determined in consideration of the rated load of the monitoring device.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a circuit breaker with a current transformer as various embodiments according to the present invention and a distribution monitoring facility equipped with the same will be described with reference to FIGS.

First, a circuit breaker with a current transformer as a first embodiment according to the present invention and a distribution monitoring facility equipped with the same will be described with reference to FIGS. 1 to 4. As shown in FIG. 1, the circuit breaker with a current transformer according to the first embodiment includes a circuit breaker 10, two current transformers 20, 20, and
The fixtures 30 and 30 for fixing the two current transformers 20 and 20 to the circuit breaker 10 are provided.

As shown in FIGS. 1 and 2, the circuit breaker 10 includes a switch (not shown) whose contacts are connected to each other or separated from each other, and a circuit breaker casing 11 which covers the switch.
And the mounting plates 12 and 12 mounted on the back surface of the circuit breaker casing 11 and the contacts of the switch, and penetrating the back surface of the circuit breaker casing 11 and the mounting plate 12 mounted here to the outside. And the terminals 13 and 14 made of copper plates exposed to the outside. As terminals, three power supply side terminals 13, 13, 13 and three load side terminals 1 are also provided.
There are 4, 14, and 14.

The current transformer 20 includes a main body 21 in which an annular iron core (not shown) and a secondary coil (not shown) wound around the iron core are housed, and the secondary side. The output part 23 is provided with an output end 24 to which the end part of the coil is connected. The body 21 has a through hole 22 through which the load-side terminal 14 of the circuit breaker 10 can be inserted. Around this through hole 22,
The annular iron core described above is arranged.

The fixture 30 has a current transformer connecting portion 31 and a terminal connecting portion 32. Each connecting portion 31 of the fixture 30,
A screw hole is formed in 32. Two current transformers 2
0 and 20 are three load side terminals 14 and 1 of the circuit breaker 10.
Two load side terminals 14 and 14 of the four and four are respectively attached to the two load side terminals 14 and 14 in a state of being inserted into the through holes 22 and 22 of the current transformers 20 and 20, respectively. In this state, the fixture 30 is fixed to the current transformer 20 by screwing the screw 33 into the screw hole of the current transformer connecting portion 31 and screwing the screw 33 into the current transformer 20. . Further, the fixture 30 has a terminal connecting portion 32.
The screw 34 is passed through the screw hole of the circuit breaker 1.
0 is loaded into the load-side terminal 14 and the load-side terminal 1
4 is fixed. That is, the current transformers 20, 20 are
The circuit breaker 1 is made by the attachments 30, 30 and the screws 33, 34.
It is fixed at 0.

The size of each part of the current transformer 20 and the circuit breaker 10 will be described with reference to FIG.

The three power supply side terminals 13, 13, 13 are provided side by side in the lateral direction on the upper part of the circuit breaker casing 11. Also, the three load side terminals 14, 14, 14 are
The circuit breaker casing 11 is provided below the circuit breaker casing 11 side by side. Power supply side terminals 13, 13, 13 in the lateral direction
Mutual distance L and load side terminals 14 and 1 in the lateral direction
The mutual distance L between 4 and 14 is 44 mm. Also, the lateral width a of each terminal, that is, the thickness of each terminal is 8 m.
m. The vertical width b of each terminal is 28 mm.

The lateral width W of the current transformer body 21 is
58 mm, the inner diameter φ of the through hole 22 of the main body 21 is 30
mm.

When the lateral terminal spacing is L and the lateral terminal width is a, the width of the current transformer main body 21 that can be mounted on the terminal 14 can be expressed as W as follows. W / 2 ≦ (L−a / 2) W ≦ (2L−a) ... (Formula 1) By the way, here, as described above, the terminal interval L of the circuit breaker 10 is 44 mm, the end width a is 8 mm, and the current transformer main body 21 Since the width W is 58 mm, each dimension satisfies (Equation 1) as follows. 58 ≦ (2 × 44−8) = 80 Therefore, the current transformer 20 that satisfies (Equation 1) is the breaker 10
It can be attached to the terminal.

The circuit breaker with a current transformer described above is
As shown in FIGS. 3 and 4, it is attached to the power distribution board 40. In addition to the circuit breaker with the current transformer, the power distribution board 40 has a normal circuit breaker 4 without the current transformer.
1, 42, 43, etc. are attached. The load side terminal 14 and the power source side terminal 13 of the circuit breaker with a current transformer are connected to the power source and other circuit breakers 41, 42, 43 and the like by main cables 18 and 19, respectively.

The distribution monitoring equipment as one embodiment according to the present invention includes a circuit breaker with a current transformer described above and current transformers 20 and 20 provided in the breaker with a current transformer. The monitoring device 50 receives the output and monitors the current flowing through the circuit breaker 10, and the microcomputer 60 that displays the output from the monitoring device 50. Monitoring device 50
Are fixed to the monitoring device base 51. The monitoring device 50 and the output end 24 of the current transformer 20 are electrically connected by an electric signal cable 52. This monitoring device 50
Is the current of the equipment in the switchboard, as well as the voltage, power amount, power factor,
Also monitor temperature etc. For this reason, the switchboard is also provided with a transformer or the like for monitoring the voltage of the devices and the like therein, and the output from this transformer is also input. The monitoring device 50 also has a function of displaying the monitoring result. Therefore, it is not necessary to provide the microcomputer 60 for displaying the monitoring result and the like, but here, in order to be able to grasp the monitoring result from the control room by providing the switchboard and the monitoring device 50 in the vicinity of the electric equipment, A microcomputer 60 is provided.

Here, the secondary side rated load of the current transformer 20 will be described. Since the secondary side rated load affects the size of the current transformer 20, it is important to determine the secondary side rated load.

First, the preconditions for determining the secondary load of the current transformer 20 will be described.

This current transformer 20 is designed so that when a current of 400 A flows from the power source side terminal 13 of the circuit breaker 10 to the load side terminal 14,
It is assumed that a current of 5A flows through the secondary coil of the current transformer 20. Further, it is assumed that the monitoring device 50 has a required rated load of 0.1 VA. Furthermore, the electrical signal cable 52 has a resistance value per unit length of 0.0165.
It is assumed that the total wiring length is 20 m (one way: 10 m) in Ω / m.

Under the above preconditions, the electric power P ₁ consumed by the current transformer 20 and the electric signal cable 52 is 8.25 VA as follows. P ₁ = (resistance value of electric signal cable) × (current flowing in secondary coil) ² = (0.0165Ω / m × 20m) × (5A) ² = 8.25VA Further, power P consumed by the monitoring device 50 ₂ is the rated load of 0.1 VA of the monitoring device 50. P ₂ = 0.1 VA Therefore, under the above preconditions, the secondary side rated load P ₀ required for the current transformer 20 may be 8.35 VA as follows. P ₀ = P ₁ + P ₂ = 8.25VA + 0.1VA = 8.35VA As described above, the secondary side rated load P ₀ of the current transformer 20 is preferably 8.35VA in terms of performance, but here, In order to reduce the size of the current transformer 20, a current rating of 5.0 VA is used although the primary side current-secondary side current characteristic of the current transformer 20 is slightly deteriorated.

In the circuit breaker with a current transformer according to the first embodiment described above, since the current transformer is attached to the circuit breaker in advance, when the current flowing through the circuit breaker 10 is to be monitored, As a result of eliminating the need to attach a current transformer to the cables 18 and 19, the main cables 18 and 19 are once detached and bent into a desired shape, and then the main cables 18 and 19 are again attached.
It is possible to omit troublesome work such as mounting.

In the circuit breaker with a current transformer according to this embodiment, since the current transformer 20 is directly attached to the terminal 14 made of a copper plate, the main cable 1 in which the copper wire is covered with an insulator is used.
It is possible to use a current transformer having a smaller diameter of the through hole 22 than that of the current transformer itself, that is, a current transformer having a smaller diameter. Further, in this embodiment, the current transformer 20
As the secondary side rated load is less than the secondary side rated load of the current transformer determined by considering the rated load of the monitoring device 50 and the length of the current signal cable, the current rating of the current transformer is used. The size can be smaller. Therefore, the breaker casing 11 does not exist around the power distribution board 40, and the current transformer 20 is attached to the side with a relatively large space (see FIG. 4). It is possible to save the space of the power distribution board on which the circuit breaker with a built-in circuit is mounted.

In the above, the three load side terminals 14,
Left and right two load side terminals 14, 14
However, the present invention is not limited to this, and the three load side terminals 14, 14,
All 14 may be equipped with a current transformer. However, in this case, the width of the current transformer body in the lateral direction needs to satisfy the relationship of (Equation 2) shown below.

W / 2 ≦ L / 2 W ≦ L ... (Equation 2) Next, a circuit breaker with a current transformer according to a second embodiment of the present invention will be described with reference to FIG. . In the first embodiment, the terminals 13 and 14 of the circuit breaker 10 are parallel to the vertical direction, but in this embodiment, the terminals 13a and 14a of the circuit breaker 10a are parallel to the horizontal direction.

Therefore, in this embodiment, the terminal 13
In order to correspond to the directions of a and 14a, the terminal connecting portion 32a of the mounting plate 30a is parallel to the lateral direction. In this embodiment, except that the shape of the mounting plate 30a is different,
Since it is the same as that of the first embodiment, the same effects as those of the first embodiment can be obtained.

Next, a circuit breaker with a current transformer according to a third embodiment of the present invention will be described with reference to FIG. In the first and second embodiments, the current transformer 20 and the fixtures 30 and 30a are separate bodies, but in this embodiment,
The current transformer 20b in which the mounting portion 25 instead of the mounting tools 30 and 30a is integrally formed is used.

The current transformer 20b has a mounting portion 2 which contacts the main surface of the terminal 14 when the current transformer 20b is mounted on the terminal 14.
5 is integrally formed with the main body 21b. A screw hole is formed in the mounting portion 25. This current transformer 20b
A screw 33 is passed through a screw hole of the mounting portion 25, and the screw 33 is screwed into the terminal 14 and fixed to the circuit breaker 10. Thus, the current transformer 2 in which the mounting portion 25 is formed
By using 0b, the number of screws for fixing the current transformer to the circuit breaker can be reduced. It should be noted that this embodiment is the same as the first embodiment except that the shape of the current transformer 20b is different, so that the same effects as those of the first embodiment can be obtained except the effects relating to the screws. .

Next, a circuit breaker with a current transformer according to a fourth embodiment of the present invention will be described with reference to FIG. In each of the above embodiments, the current transformers 20 and 20b are fixed to the terminals, but in this embodiment, the current transformer 20c is directly fixed to the mounting plate 12 of the circuit breaker 10 with an adhesive or the like. Therefore, the fixture 3 for fixing the current transformer to the circuit breaker
0, a screw 33, a screw hole through which the screw 33 passes, and the like are not necessary at all. This embodiment is also the same as the first embodiment except that the method of attaching the current transformer is different, so that the same effect as that of the first embodiment can be obtained except the effect relating to the attachment of the current transformer. .

Although the circuit breakers with current transformers according to the first to fourth embodiments of the present invention have been described above, the point is that the terminals of the circuit breakers are inserted into the through holes of the current transformers. Then, if the current transformer is fixed so as not to move relative to the circuit breaker, the current transformer may be fixed to the circuit breaker in any way.

In all of the above embodiments, the current transformer is attached to the load side terminal, but it goes without saying that the current transformer may be attached to the power side terminal.

[0035]

According to the present invention, when a distribution monitoring device for monitoring a current flowing through a main circuit in a distribution board or the like is attached, since a current transformer is attached to the breaker in advance, the main cable is changed. As a result of eliminating the need to attach a sink, once disconnecting the main cable and bending it to the desired shape,
It is possible to omit the troublesome work such as attaching the main cable again, and it is possible to greatly reduce the number of work steps.

[Brief description of drawings]

FIG. 1 is a perspective view of a circuit breaker with a current transformer as a first embodiment according to the present invention.

FIG. 2 is a view on arrow II in FIG.

FIG. 3 is an explanatory diagram showing an overall configuration of a distribution monitoring facility as an embodiment according to the present invention.

FIG. 4 is a view on arrow IV in FIG.

FIG. 5 is a perspective view of a circuit breaker with a current transformer as a second embodiment according to the present invention.

FIG. 6 is a perspective view of a circuit breaker with a current transformer as a third embodiment according to the present invention.

FIG. 7 is a perspective view of a circuit breaker with a current transformer as a fourth embodiment according to the present invention.

FIG. 8 is an explanatory diagram showing an overall configuration of a conventional power distribution monitoring facility.

[Explanation of symbols]

10, 10a ... Circuit breaker, 11 ... Circuit breaker casing, 12
... Mounting plate, 13, 13a ... Power supply side terminal, 14, 14a ...
Load side terminals, 18, 19 ... Main cable, 20, 20b,
20c ... Current transformer, 21, 21b ... Current transformer main body, 22 ... Through hole, 23 ... Output part, 24 ... Output end, 25 ... Mounting part, 3
0, 30a ... Fixture, 40 ... Power distribution base, 50 ... Monitoring device, 51 ... Monitoring device base, 52 ... Electric signal cable, 6
0: microcomputer.

Claims (3)

[Claims] 1. A circuit breaker having a power source side terminal and a load side terminal, for interrupting a current flowing from the power source side terminal to the load side terminal, and a main body having a through hole formed therein. A current transformer that outputs a current amount proportional to the amount of current flowing through the conductor passed through the hole, wherein the current transformer is one of the power source side terminal and the load side terminal of the circuit breaker. A circuit breaker with a current transformer, characterized in that one of them is inserted into the through hole of the current transformer and is fixed so as not to move relative to the circuit breaker. 2. The circuit breaker with a current transformer according to claim 1, further comprising a plurality of said power supply side terminals, said plurality of power supply side terminals being arranged at a constant interval L in a given direction. The width of the power supply terminal in the constant direction is a constant width a, and the plurality of load side terminals are provided, and the plurality of load side terminals are arranged in the constant direction at the constant distance L from each other. The width of the terminal in the constant direction is the constant width a, the main body of the current transformer, the width in the constant direction when the current transformer is attached to either the power supply side terminal or the load side terminal. Is formed to be equal to or less than a value obtained by subtracting the constant terminal width a from a value obtained by doubling the constant terminal distance L, and a circuit breaker with a current transformer. 3. A circuit breaker with a current transformer according to claim 1 or 2, and a monitoring device which receives an output from the current transformer and monitors a current flowing through the circuit breaker. Distribution monitoring equipment characterized by the following.