JP2002231082A - Current limiting circuit breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a high performance current limiting circuit breaker. SOLUTION: The current limiting circuit breaker comprises a breaker part of opening and shutting the current circuit having a fixed electrode, a movable electrode and a movable electrode driving means, a coil connected in series to the above current circuit, and a movable core that is interlocked with the opening action of the above movable electrode driving means based on occurrence of abnormal current and comes closer to the above coil so as to increase the inductance of the coil. The coil is a superconducting coil.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an AC circuit breaker having a current limiting function for suppressing an abnormal current increase such as a short-circuit current at the time of a power system accident, and more particularly, to an inductance of a coil connected in series to a power path. The present invention relates to a circuit breaker that cuts off while limiting a short-circuit current due to an increase in current.

[0002]

2. Description of the Related Art As a prior art, for example,
There is a current limiting device disclosed in JP-109206A. This will be described with reference to FIG. Referring to FIG. 1, the current limiting device 1 uses a magnetic attractive force generated in the coils 3a and 3b when an abnormally large short-circuit current flows through the coils 3a and 3b connected in series to an AC line (not shown). This is a device for adsorbing the movable magnetic body 6 to the fixed magnetic body 2 and increasing the inductance of the coils 3a and 3b wound around the fixed magnetic body 2 to limit the current.

[0003]

SUMMARY OF THE INVENTION The present invention provides a current-limiting function which improves the structure of the current-limiting means described above, and which is organically assembled into a circuit breaker to effectively suppress an increase in current. It is an object of the present invention to provide a current limiting circuit breaker provided with a current limiter.

[0004]

According to a first aspect of the present invention, there is provided a switching unit having a fixed electrode for opening and closing a current path, a movable electrode, and a movable electrode driving means, a coil connected in series to the current path, A movable iron core approaching the coil so as to increase the inductance of the coil in conjunction with the opening operation of the movable electrode driving means based on occurrence of an abnormal current.

According to a second aspect of the present invention, there is provided a control device comprising: a cutoff portion having a fixed electrode for opening and closing a current path; a movable electrode; and a movable electrode driving means; a coil connected in series to the current path; And a movable core approaching the coil so as to increase the inductance of the coil by being attracted by the magnetic attraction generated in the coil.

According to a third aspect of the present invention, there is provided a blocking portion having a fixed electrode for opening and closing a current path, a movable electrode, and a movable electrode driving means, and connected in series to the current path in conjunction with an opening operation of the movable electrode driving means. And a fixed core that approaches the coil such that its inductance increases in conjunction with the opening operation of the movable electrode driving means based on the occurrence of an abnormal current.

According to a fourth aspect of the present invention, there is provided a breaking portion having a fixed electrode for opening and closing a current path, a movable electrode, and a movable electrode driving means, a coil connected in series to the current path, and passing through an axis of the coil. A fixed iron core that forms a magnetic circuit and a gap is formed in a part of the magnetic circuit, and a movable core that fits in the gap so that the inductance of the coil increases in conjunction with the opening operation of the movable electrode. It is characterized by having.

According to a fifth aspect of the present invention, in the current-limiting circuit breaker according to the fourth aspect, the coil is partially formed through a superconducting member, and the gap of the fixed iron core is provided in the axial portion of the coil. It is characterized by.

According to a sixth aspect of the present invention, in the current-limiting circuit breaker according to the fourth aspect, the gap portion of the fixed iron core is provided in the middle of the magnetic circuit except for the axial portion of the coil, and the movable iron core approaches the gap portion. It is characterized in that it is configured to fit.

[0010] The invention of claim 7 is the invention of claim 4 or 5.
Is characterized in that the movable iron core is configured to approach so as to be positioned in parallel with the extending direction of the gap of the fixed iron core.

According to an eighth aspect of the present invention, in the current limiting circuit breaker according to any one of the first to fourth, sixth, and seventh aspects, the coil is a superconducting coil.

According to a ninth aspect of the present invention, in the current limiting circuit breaker according to the eighth aspect, the movable iron core is a permanent magnet.

According to a tenth aspect of the present invention, in the current limiting circuit breaker according to the ninth aspect, the coil is a superconducting ring.

According to an eleventh aspect of the present invention, in the current limiting circuit breaker according to the fourth aspect, a superconducting ring is interposed between the movable iron core and the coil.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 The current-limiting circuit breaker according to the first embodiment includes a coil connected in series with a current path, and an iron core interlocked with a movable electrode driving unit (hereinafter, also referred to as a movable electrode driving unit) constituting a breaking unit. By increasing the inductance of the coil in close proximity to the opening operation of the movable electrode driving means, an increased current generated in the current path is suppressed and cut off. Hereinafter, this will be described with reference to FIGS. 1 to 3 are explanatory diagrams of the operation of the apparatus. FIG. 1 is an explanatory diagram at the time of steady state, FIG. 2 is an explanatory diagram at the time of current limiting, and FIG. FIG. 4 is a diagram showing a calculation circuit, and FIG. 5 is a diagram showing a calculation result.

In FIGS. 1 to 3, reference numeral 10 denotes a cut-off portion, and a fixed electrode 11 for opening and closing a current path (not shown).
And a movable electrode 12 and a movable electrode driving means 13 for driving the movable electrode 12 so as to be able to freely contact and separate from the fixed electrode 11. When an abnormal current is generated in the current path, the movable electrode driving means 13 operates to separate the movable electrode 12 from the fixed electrode 11.

Reference numeral 20 denotes a coil connected in series to the current path. For this coil 20, the coil 2
A movable iron core 21 is provided along the zero axis so as to approach and enter the coil 20. The movable core 21 is connected to a link mechanism configured as the movable electrode driving unit 13 in the illustrated example, and
3 is configured to approach the coil 20 in accordance with the opening operation and to enter from the axial direction of the coil 20.

Next, the operation will be described. In the steady state shown in FIG. 1, the impedance of the coil 20 is small. Based on the occurrence of an abnormal current in the current path (not shown),
Receives the operation command, the movable electrode driving means 13 operates. That is, as shown in FIG. 2, the movable electrode driving means 13 performs an opening operation in a direction of separating the movable electrode 12 from the fixed electrode 11, and from the start of the opening operation to immediately before the end of the opening operation.
Since the movable electrode 12 is slidably movably in contact with the fixed electrode 11 while maintaining the contact state, the system current flows until the movable electrode 12 is completely separated from the fixed electrode 11.

At this time, since the movable iron core 21 approaches the coil 20 in conjunction with the operation of the movable electrode driving means 13, the inductance of the coil 20 increases and the current limiting effect is exhibited. In FIG. 3, the coil 20
Since the movable electrode 12 is separated from the fixed electrode 11 in a current-limiting state where the impedance is large, the system current can be cut off smoothly.

In the first embodiment, for example, when a current was calculated in a circuit as shown in FIG. 4 in which the coil 20 was replaced with a superconducting coil, a result as shown in FIG. 5 could be obtained. . In FIG. 5, when a short circuit occurs at time zero and the inductance increases after one cycle (17 ms), the movable electrode driving means 13 starts operating. The inductance becomes 7mH and the coil 2
It can be seen that the current is limited by the increase in the inductance of 0.

In the first embodiment, the movable core 2
1 is linked with the opening operation of the movable electrode 12 through a link mechanism as the movable electrode driving means 13, but without any intermediary of the link mechanism as the movable electrode driving means 13, Then, the opening operation of the movable electrode 12 may be linked. For example, in the case of the first embodiment, a configuration may be adopted in which the movable iron core 21 is made to approach the coil 20 by being attracted by magnetic attraction generated when an abnormal current flows through the coil 20 (not shown).

Embodiment 2 FIG. As shown in FIG. 6, the current limiting circuit breaker according to the second embodiment differs from the current limiting circuit breaker according to the first embodiment in that a member corresponding to the movable iron core 21 according to the first embodiment is fixed at an appropriate position. An iron core 22 is provided, and the coil 20 is configured to approach the fixed iron core 22 so as to be able to freely contact and separate therefrom. In the illustrated example, the movable coil 20 is configured to interlock with the movable electrode 12 via a link mechanism as the movable electrode driving means 13 in accordance with the opening operation of the movable electrode 12. It is free.

According to the second embodiment, the same functions and effects as those of the first embodiment can be exhibited. The configuration of the first embodiment is effective when the coil 20 is lighter than the fixed iron core 22.

Embodiment 3 FIG. In the third embodiment, as shown in FIG. 7, in the current limiting circuit breaker described in the first embodiment, a fixed iron core 24 for forming a magnetic circuit passing through the axis of the coil 20 is provided in the coil 20. ,
An air gap 25 is provided in a part of the fixed iron core 24, and the movable iron core 21 is provided so as to be close to the air gap 25. The air gap 25 is provided in the fixed core 24 corresponding to the axis portion of the coil 20, and the movable core 21
A movable electrode driving means 13 for opening the movable electrode 12
The magnetic circuit is formed by approaching and closing the gap 25 according to the opening operation of the movable electrode 12 via the link mechanism as described above. The cores such as the movable core 21 and the fixed core 24 are preferably made of a magnetic material.

The movable iron core 21 includes the coil 20 and the fixed iron core 2.
4, the inductance of the coil 20 is increased. Further, the movable iron core 21 is
, The inductance of the coil 20 is further increased, and the impedance before and after the interruption can be increased as compared with the first and second embodiments, whereby a large current limiting effect can be exhibited. By forming the iron cores such as the movable iron core 21 and the fixed iron core 24 from a magnetic material, the above-mentioned effects can be further increased.

Embodiment 4 As shown in FIG. 8, the fourth embodiment has a configuration in which, in the current-limiting circuit breaker described in the third embodiment, the coil 20 is formed by superposing a superconducting member 33 on a part of the coil 20 in series. It is what it was. The superconducting member 33 is, for example, a superconducting thin film, and is disposed at the position of the gap 25 of the fixed iron core 24, in the illustrated example, at the axis of the coil 20 in which the gap 25 into which the movable iron core 21 enters is formed. I have. According to the fourth embodiment, the superconducting member 33 can reduce the impedance in a steady state. On the other hand, when an abnormal current occurs (at the time of an accident), the superconducting state is broken, and the same operation and effect as in the third embodiment are exhibited.

Embodiment 5 FIG. In the fifth embodiment, as shown in FIG. 9, in the current limiting circuit breaker described in the third embodiment, a fixed iron core 24 is formed so that gaps 25, 25 are formed at two places in a magnetic circuit. is there. In the illustrated example, the fixed iron core 24 is formed in a U-shape so that a relatively long interval is formed in the middle of the magnetic circuit excluding the axis portion of the coil 20, and the movable iron core 21 is long enough to bridge between both ends of the U-shape. Has formed. This movable iron core 21 is fixed iron core 2
4, between the both ends of the U-shape, that is, in a configuration that can be freely contacted and separated while maintaining a state parallel to the extending direction of the gap portion where the magnetic circuit is formed,
Between both ends of the movable iron core 21 and the U-shaped ends,
Each of the gaps, that is, a total of two gaps 25, 25 is formed.

According to the fifth embodiment, two air gaps 25, 25 are formed in the fixed iron core forming the magnetic circuit of the coil 20.
By providing, the gap 25 can be formed longer than in the third embodiment, so that steady-state inductance can be reduced. In the illustrated example, two gaps are formed. However, a plurality of relatively long gaps are provided, and the movable cores respectively corresponding to these gaps are simultaneously brought into close proximity to be accommodated (not shown). ), A desired number of two or more voids can be provided.

Embodiment 6 FIG. In the sixth embodiment, as shown in FIG. 10, the movable core 21 is parallel to the extending direction of the gap 25 formed in the fixed core 24, that is, the magnetic core 21 formed by the fixed core 24 and passing through the gap 25. The configuration is such that it is close to the fixed iron core 24 so as to be positioned in parallel with the circuit. In FIG. 10, the movable electrode driving means 13
Has been omitted. According to the sixth embodiment, the movable iron core 21 only needs to be positioned in parallel with the magnetic circuit of the coil 20.
The degree of freedom in the design of the device is increased as compared with a configuration in which is stored in the gap portion 25, and for example, restrictions due to the type of the movable electrode driving means 13 and the like can be reduced.

Embodiment 7 The seventh embodiment is different from all the above-described embodiments except the fourth embodiment in that the coil 2
0 is replaced with a superconducting coil 30. FIG. 11 shows a configuration corresponding to the first embodiment as an example. Normally, a current equal to or lower than the critical current is applied to the superconducting coil 30, but the superconducting state is broken by the generation of an abnormal current. Therefore, at the time of an accident in which an abnormal current is generated, a resistance is generated in the coil 30 and an increase in the inductance of the coil 30 produces a current limiting effect as in the above-described embodiments.

When the superconducting coil 30 is used as described above, Joule heat is eliminated from the coil 30, so that an efficient current-limiting circuit breaker with small loss can be obtained. or,
If the coil is a superconducting coil that can be operated at the temperature of liquid nitrogen, a more efficient current-limiting circuit breaker can be obtained.

Embodiment 8 FIG. In the eighth embodiment, similarly to the above-described seventh embodiment, in all of the above-described embodiments except the fourth embodiment, the movable iron core 21 is replaced with the permanent magnet 29, and the coil 20 is replaced with the superconducting coil 30. The configuration is as follows. FIG. 12 shows a configuration corresponding to the first embodiment as an example.

In FIG. 12, based on the generation of the abnormal current, the permanent magnet 29 approaches the superconducting coil 30 in conjunction with the opening operation of the movable electrode driving means 13 of the interrupting section 10, and in the illustrated example, the superconducting coil As the vehicle enters along the axis of 20, the superconducting state of the components of the superconducting coil 30 is sequentially destroyed by the magnetic field as the vehicle enters. Thus, similarly to the seventh embodiment, a resistance is generated in the coil 30 and a current limiting effect is exhibited by an increase in the inductance of the coil 30.

Embodiment 9 Embodiment 9 is different from Embodiment 8 in that superconducting coil 30 of Embodiment 8 is replaced with superconducting ring 31.
The configuration is replaced with Embodiment 9
Accordingly, the same function and effect as those of the eighth embodiment are exerted. FIG. 13 shows a configuration corresponding to the eighth embodiment as an example.

Embodiment 10 FIG. Embodiment 10 corresponds to FIG.
As shown in FIG. 4, the coil 20 according to the third embodiment
A superconducting ring 32 is disposed between the fixed core 24 and the fixed core 24 so as to shield a magnetic field generated in the coil 20.
According to the tenth embodiment, the coil 20
Is shielded by the superconducting ring 32, so that the inductance of the coil 20 can be reduced.

On the other hand, when an abnormal current is generated, the effect of shielding the magnetic field by the superconducting ring 32 is reduced.
A magnetic field of 0 interacts with the iron core, that is, the movable iron core 21 and the fixed iron core 24, the inductance of the coil 20 increases, and the current limiting effect is exhibited as in the above embodiments. still,
In this configuration, since no current is supplied to the superconducting ring 32 from the outside, there is an advantage that wiring such as a current lead wire becomes unnecessary.

[0037]

According to each of the first to eleventh aspects of the present invention, a high-performance current limiting device having a current limiting function capable of effectively suppressing an abnormal current increase and interrupting a small current. Circuit breakers can be provided.

According to each of the first to third aspects of the present invention,
In any case, the impedance of the coil is small at steady state,
When an abnormal current is generated, the movable iron core operates in conjunction with the opening operation of the interrupting section, and the current limiting effect is exhibited by the increase in coil inductance. In addition, when the interrupt is interrupted, the coil is movable with a large impedance (current limiting). The electrode can be spaced from the fixed electrode.

According to the fourth aspect of the invention, the impedance before and after the interruption can be further increased.

According to the fifth aspect of the present invention, the impedance at the steady state can be reduced by the magnetic shielding effect of the superconducting member, and the current limiting effect can be exerted by breaking the superconducting state when an abnormal current is generated.

According to the sixth aspect of the present invention, since a plurality of or relatively long voids of the fixed iron core forming the magnetic circuit of the coil can be formed, the inductance of the coil in a steady state can be reduced.

According to the seventh aspect of the present invention, since the movable iron core is brought closer to a position parallel to the gap portion of the fixed iron core, the degree of freedom in equipment design is increased as compared with the case where the movable iron core is accommodated in the gap portion. A current limiting circuit breaker can be manufactured irrespective of the type of the movable electrode driving means.

According to the eighth aspect of the present invention, since the coil is a superconducting coil, it is possible to provide an efficient current-limiting circuit breaker which does not generate Joule heat and has a small loss. Further, when an abnormal current is generated, a resistance is generated in the coil and the inductance increases, so that a current limiting circuit breaker having a high current limiting effect can be provided.

According to the ninth and tenth aspects of the present invention, when the permanent magnet approaches the superconducting member (coil or ring), the superconducting state is broken (quenched) by the magnetic field, and the coil or ring becomes a resistor. Thus, the current limiting effect is exhibited.

According to the eleventh aspect of the present invention, since the superconducting material ring is interposed between the coil and the fixed iron core, the magnetic field of the coil is shielded by the superconducting ring in a normal state, so that the inductance of the coil is reduced. Can be done. On the other hand, when an abnormal current is generated, the shielding effect of the superconducting ring decreases, and the magnetic field of the coil interacts with the iron core to increase the inductance, so that a high current limiting effect can be exhibited.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram of Embodiment 1 in a steady state.

FIG. 2 is an explanatory diagram at the time of current limiting according to the first embodiment.

FIG. 3 is an explanatory diagram of the first embodiment at the time of interruption.

FIG. 4 is a diagram illustrating a calculation circuit according to the first embodiment;

FIG. 5 is a diagram showing calculation results of the first embodiment.

FIG. 6 is an explanatory diagram of Embodiment 2 in a steady state.

FIG. 7 is an explanatory diagram of Embodiment 3 in a steady state.

FIG. 8 is an explanatory diagram of Embodiment 4 in a steady state.

FIG. 9 is an explanatory diagram of Embodiment 5 in a steady state.

FIG. 10 is an explanatory diagram of Embodiment 6 in a steady state.

FIG. 11 is an explanatory diagram of Embodiment 7 in a steady state.

FIG. 12 is an explanatory diagram of Embodiment 8 in a steady state.

FIG. 13 is an explanatory diagram of the ninth embodiment in a steady state.

FIG. 14 is an explanatory diagram of Embodiment 10 in a steady state.

FIG. 15 is a cross-sectional view of a conventional current limiter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Interruption part, 11 Fixed electrode, 12 Movable electrode, 13
Link mechanism (movable electrode driving means), 20 coils, 2
1 movable iron core, 22, 24 fixed iron core, 23 windings, 2
5 gap portion, 29 permanent magnet, 30 superconducting coil (superconducting member), 31, 32 superconducting ring (superconducting member),
33 Superconducting thin film (superconducting member).

Continued on the front page (72) Inventor Shiro Nakamura 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Within Mitsubishi Electric Corporation (72) Inventor Masato Yamada 3-2-2 Nakanoshima, Kita-ku, Osaka-shi, Kansai Electric Power F term in reference (reference) 5E048 AB04 AC01 AD02 5G013 AA01 AA04 BA01 CA05 5G034 AA20

Claims (11)

[Claims] 1. A breaking part having a fixed electrode for opening and closing a current path, a movable electrode, and a movable electrode driving means, a coil connected in series to the current path, and a movable electrode driving means based on abnormal current generation. And a movable core approaching the coil so as to increase the inductance of the coil in conjunction with the opening operation. 2. A breaking part having a fixed electrode for opening and closing a current path, a movable electrode, and a movable electrode driving means, a coil connected in series to the current path, and an abnormal current generated in the coil based on occurrence of an abnormal current. And a movable core approaching the coil so as to increase the inductance of the coil by magnetic attraction. 3. A blocking part having a fixed electrode for opening and closing a current path, a movable electrode, and a movable electrode driving means, a coil connected in series with the current path in conjunction with an opening operation of the movable electrode driving means, A current-limiting circuit breaker, comprising: a fixed core that approaches the coil such that its inductance increases in conjunction with an opening operation of the movable electrode driving unit based on occurrence of an abnormal current. 4. A circuit, comprising: a blocking portion having a fixed electrode for opening and closing a current path, a movable electrode, and a movable electrode driving means; a coil connected in series to the current path; and a magnetic circuit passing through the axis of the coil. A fixed iron core having a gap formed in a part of the magnetic circuit, and a movable core that fits in the gap so as to increase the inductance of the coil in conjunction with the opening operation of the movable electrode, Current limiting circuit breaker. 5. The current-limiting circuit breaker according to claim 4, wherein the coil is partially formed through a superconducting member, and a gap of the fixed iron core is provided in an axial portion of the coil. 6. The current limiting device according to claim 4, wherein the gap of the fixed iron core is provided in the middle of the magnetic circuit excluding the axis of the coil, and the movable iron core is set close to the gap. Circuit breaker. 7. The current-limiting circuit breaker according to claim 4, wherein the movable iron core is configured to approach so as to be positioned in parallel with the extending direction of the gap of the fixed iron core. 8. The current limiting circuit breaker according to claim 1, wherein the coil is a superconducting coil. 9. The current limiting circuit breaker according to claim 8, wherein the movable iron core is a permanent magnet. 10. The current limiting circuit breaker according to claim 9, wherein the coil is a superconducting ring. 11. The current limiting circuit breaker according to claim 4, wherein a superconducting ring is interposed between the movable iron core and the coil.