JP2004064842A

JP2004064842A - Current limiting device

Info

Publication number: JP2004064842A
Application number: JP2002217702A
Authority: JP
Inventors: Sadajiro Mori; 森　貞次郎; Atsushi Sawada; 澤田　敦; Kazufumi Hayashi; 林　和史
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2002-07-26
Filing date: 2002-07-26
Publication date: 2004-02-26

Abstract

<P>PROBLEM TO BE SOLVED: To provide a current limiting device of smaller size, less weight, and lower cost. <P>SOLUTION: A first iron core 2C and a second iron core 2D magnetically saturate when no current flows a coil 3 and when a load current is energized to the coil 3. If a short-circuit current flows the coil 3, the magnetic saturation is released either at the first iron core 2C or at the second iron core 2D. The sectional area of magnetic path of the first iron core 2C or the second iron core 2D is small so that the first iron core 2C or the second iron core 2D whose magnetic saturation has been released magnetically saturates as the current flowing the coil 3 increases when the short-circuit current flows the coil 3. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
この発明は、電気回路の短絡事故等で発生する過電流を抑制する限流器に関するものである。
【０００２】
【従来の技術】
図１３は本出願人が既に出願している限流器（特願２０００−３０３４５０）と類似の限流器の正断面図、図１４は図１３の限流器の側断面図である。
図において、１Ａは上面がＮ極、下面がＳ極に着磁された角柱状の第１の永久磁石、１Ｂは第１の永久磁石１Ａに対向し上面がＳ極、下面がＮ極に着磁された角柱状の第２の永久磁石、２Ａ，２Ｂは互いに対向しているとともに、第１の永久磁石１Ａおよび第２の永久磁石１Ｂを挟持した珪素鋼板からなる第１および第２の鉄心である。第１および第２の永久磁石１Ａ，１Ｂは着磁されていることで、第１および第２の鉄心２Ａ，２Ｂ内に作る磁場は強いが、もし一方の永久磁石１Ａ，１Ｂの極性が逆であれば、鉄心２Ａ，２Ｂ内に作る磁場は弱められる。ここで、第１の永久磁石１Ａ、第２の永久磁石１Ｂ、第１の鉄心２Ａおよび第２の鉄心２Ｂにより、閉磁気回路を構成している。
３は第１および第２の鉄心２Ａ，２Ｂの外側に導線が単層状態で巻かれたコイル、６Ａはコイル３の第１の端子、６Ｂはコイル３の第２の端子である。なお、コイル３は導線を多層状態に巻いて構成してもよい。そして、コイル３に電流が流れていない場合、第１および第２の鉄心２Ａ，２Ｂは第１および第２の永久磁石１Ａ，１Ｂにより磁気飽和されている。
【０００３】
図１５は第１の鉄心２ＡのＢ−Ｈ特性図、図１６は第２の鉄心２ＢのＢ−Ｈ特性図である。なお、Ｈは磁界強度、Ｂは磁束密度を示す。
この限流器では、コイル３に電流が流れていない場合、第１の鉄心２Ａの磁界Ｈの強さはＨＡ１、第２の鉄心２Ｂの磁界Ｈの強さはＨＢ１になるよう構成されている。第１の鉄心２Ａの磁界Ｈの強さがＨＡ１のときは、第１の鉄心２Ａは図１５から分かるように磁気飽和状態にあり、鉄心２ＢのＨがＨＢ１のときは、鉄心２Ｂは図１６から分かるように磁気飽和状態にあるので、限流器のインダクタンスは小さい。
コイル３の第１の端子６Ａから交流の負荷電流が流れ込むとコイル３には磁束が発生し、第１の鉄心２Ａは一層磁気飽和し、負荷電流のピーク時において、第１の鉄心２Ａの磁界Ｈの強さはＨＡ２に移動する。これに対して、第２の鉄心２Ｂは、減磁し、第２の鉄心２Ｂの磁界Ｈの絶対値は負荷電流のピーク時において、ＨＢ２に減少するが、飽和領域にある。
【０００４】
次に、コイル３の第２の端子６Ｂから負荷電流が流れ込むと、第１の鉄心２Ａは、減磁され、電流ピーク時において磁界ＨはＨＡ３に減少するが、飽和領域にある。また、第２の鉄心２Ｂの磁界Ｈは電流ピーク時においてＨＢ３になり、第２の鉄心２Ｂは一層磁気飽和する。
上記のように、負荷電流通電時には、いずれの方向の電流が流れても第１の鉄心２Ａ、第２の鉄心２Ｂは磁気飽和しているので、限流器のインダクタンスは低い状態にある。
【０００５】
次に、短絡電流のような過大な電流がコイル３に流れた場合について説明する。
コイル３の第１の端子６Ａから短絡電流が流れ込むと、コイル３には大きな磁束が発生し、第１の鉄心２Ａの磁界Ｈは電流ピーク時にＨＡ４になり、第１の鉄心２Ａは一層大きく飽和する。これに対して、第２の鉄心２Ｂの磁界Ｈの強さは、磁気飽和領域の飽和境界点であるＨＢ６から右側の領域内であるＨＢ４である。
第２の鉄心２Ｂでは磁界ＨがＨＢ６の右側の領域に入ると磁気飽和が解け、Ｂ−Ｈ線の傾斜角度が大きい領域に入るために、限流器のインダクタンスが大きくなり短絡電流が抑制される。
【０００６】
次に、コイル３の第２の端子６Ｂから短絡電流が流れ込むと、第２の鉄心２Ｂの磁界Ｈは電流ピーク時にＨＢ５になり、第２の鉄心２Ｂは一層大きく飽和する。これに対して、第１の鉄心２Ａの磁界Ｈの強さは、磁気飽和領域の飽和境界点であるＨＡ６の左側の領域内であるＨＡ５になる。
第２の鉄心２Ａでは磁界ＨがＨＡ６の左側の領域に入ると磁気飽和が解け、Ｂ−Ｈ線の傾斜角度が大きい領域に入るために、限流器のインダクタンスが大きくなり短絡電流が抑制される。
【０００７】
上記のように、コイル３の短絡電流通電時には、いずれの方向の電流が流れても一方の鉄心２Ａ，２Ｂの磁気飽和が解かれるので、限流器のインダクタンスは高い状態になり、短絡電流が抑制される。図１７は、こうして限流器により短絡電流が限流された様子を示す図である。
【０００８】
【発明が解決しようとする課題】
上記構成の限流器では、例えば短絡電流に直流分が含まれている場合においても高インダクタンス状態を確保して短絡電流を抑制しており、その確保のために第１の鉄心２Ａおよび第２の鉄心２Ｂでは、磁路に対して垂直方向の断面積を大きくしなければならず、またこの大きな断面積を有する鉄心２Ａ，２Ｂを磁気飽和させるために永久磁石１Ａ，１Ｂの断面積も大きくしなければならず、全体が大型化すると共に重量が大きくなってしまうという問題点があった。
【０００９】
この発明は、上記のような問題点を解決することを課題とするものであって、小型化および軽量化できる等の限流器を得ることを目的とする。
【００１０】
【課題を解決するための手段】
この発明に係る限流器は、対向した一対の第１の鉄心および第２の鉄心と、前記第１の鉄心と前記第２の鉄心との間に第１の鉄心および第２の鉄心の磁場を強めるように極性配置されて設けられた第１の永久磁石および第２の永久磁石とから構成された閉磁気回路と、
前記第１の鉄心および前記第２の鉄心の外周に巻回されたコイルを備え、
前記コイルに電流が流れていないとき、およびコイルに負荷電流が通電中のときには、前記第１の鉄心および前記第２の鉄心は磁気飽和し、前記コイルに短絡電流が流れたときには、前記第１の鉄心および前記第２の鉄心の何れかで磁気飽和が解かれるようになっている限流器であって、
前記閉磁気回路には、前記コイルに前記短絡電流が流れたときにおいて、磁気飽和が解かれた前記第１の鉄心または前記第２の鉄心がコイルに流れる電流の増加に伴い磁気飽和する磁気飽和調整手段が施されている。
【００１１】
この発明に係る限流器では、磁気飽和調整手段は、第１の鉄心および第２の鉄心の磁路断面積を調整するものである。
【００１２】
この発明に係る限流器では、磁気飽和調整手段は、第１の永久磁石および第２の永久磁石の磁路断面積を調整するものである。
【００１３】
この発明に係る限流器では、磁気飽和調整手段は、第１の鉄心および第２の鉄心の材質を調整するものである。
【００１４】
この発明に係る限流器は、対向した一対の第１の鉄心および第２の鉄心と、前記第１の鉄心と前記第２の鉄心との間に第１の鉄心および第２の鉄心の磁場を強めるように極性配置されて設けられた第１の永久磁石および第２の永久磁石とから構成された閉磁気回路と、
前記第１の鉄心および前記第２の鉄心の外周に巻回されたコイルを備え、
前記コイルに電流が流れていないとき、およびコイルに負荷電流が通電中のときには、前記第１の鉄心および前記第２の鉄心は磁気飽和し、前記コイルに短絡電流が流れたときには、前記第１の鉄心および前記第２の鉄心の何れかで磁気飽和が解かれるようになっている限流器であって、
前記コイルでは、コイルの導線の巻数を調整することで、前記コイルに前記短絡電流が流れたときにおいて、磁気飽和が解かれた前記第１の鉄心または前記第２の鉄心がコイルに流れる電流の増加に伴い磁気飽和するようになっている。
【００１５】
この発明に係る限流器では、アーク電圧発生後にアーク電圧が増大する開閉器が直列に接続される。
【００１６】
この発明に係る限流器では、複数の分岐開閉器のそれぞれが限流器に直列に接続される。
【００１７】
【発明の実施の形態】
以下、この発明について説明するが、従来のものと同一、または相当部材については同一符号を付して説明する。
実施の形態１．
図１はこの発明の実施の形態１の限流器の正断面図、図２は図１の限流器の側断面図である。
図において、１Ａは上面がＮ極、下面がＳ極に着磁された角柱状の第１の永久磁石、１Ｂは第１の永久磁石１Ａに対向し上面がＳ極、下面がＮ極に着磁された角柱状の第２の永久磁石、２Ｃ，２Ｄは互いに対向しているとともに、第１の永久磁石１Ａおよび第２の永久磁石１Ｂを挟持した珪素鋼板からなる第１および第２の鉄心である。第１および第２の永久磁石１Ａ，１Ｂは着磁されていることで、第１および第２の鉄心２Ｃ，２Ｄ内に作る磁場は強いが、もし一方の永久磁石１Ａ，１Ｂの極性が逆であれば、鉄心２Ｃ，２Ｄ内に作る磁場は弱められる。ここで、第１の永久磁石１Ａ、第２の永久磁石１Ｂ、第１の鉄心２Ｃおよび第２の鉄心２Ｄにより、閉磁気回路を構成している。
３は第１および第２の鉄心２Ｃ，２Ｄの外側に導線を単層状態で巻かれたコイル、６Ａはコイル３の第１の端子、６Ｂはコイル３の第２の端子である。なお、コイル３は導線を多層状態に巻いて構成してもよい。
【００１８】
この限流器では、コイル３に短絡電流が流れたときにおいて、磁気飽和が解かれた第１の鉄心２Ｃまたは第２の鉄心２Ｄがコイル３に流れる電流の増加に伴い磁気飽和する磁気飽和調整手段が施されている。具体的には、鉄心２Ｃ，２Ｄの磁路断面積を従来の鉄心２Ａ，２Ｂと比較して小さくしてある。
図３は従来の第１の鉄心２Ａおよび実施の形態１の第１の鉄心２ＣにおけるＢ−Ｈ特性図であり、両者の特性図は同じであるが、第１の鉄心２Ｃ、第２の鉄心２Ｄを通る磁束量は断面積が減少した分、従来のものと比較して減少する。ここで、実線矢印は従来例、点線矢印は実施の形態１のそれぞれの磁界Ｈの値であり、ＨＡ１はコイル３に電流が流れていない場合の第１の鉄心２Ｃの磁界Ｈの強さ、ＨＡ２は第１の端子６Ａからコイル３に流れる負荷電流がピーク時での磁界Ｈの強さ、ＨＡ３は第２の端子６Ｂからコイル３に逆方向に流れる負荷電流がピーク時での磁界Ｈの強さである。
【００１９】
鉄心２Ｃ，２Ｄの断面積を小さくしたことで、図３から分かるように、この実施の形態１の限流器での（ＨＡ１−ＨＡ２）の値、および（ＨＡ１−ＨＡ３）の値はともに、従来のものと比較して大きくなる。
この限流器では、例えばコイル３の第２の端子６Ｂから短絡電流が流れ込むと、磁気飽和していた第１の鉄心２Ｃは磁気飽和が解け、飽和境界点ＨＡ６の左側の領域内で、Ｂ−Ｈ線の傾斜角度が大きい領域に入るために、限流器のインダクタンスが大きくなり短絡電流が抑制される。但し、鉄心２Ｃ，２Ｄの断面積が従来のものと比較して小さくなっているので、限流時のインダクタンスは小さいが、そのインダクタンスは飽和状態におけるインダクタンスよりも格段に大きい。限流時のインダクタンスが小さいことにより、限流電流が大きくなるため、飽和境界点ＨＡ７に至る。磁気飽和すると限流器のインダクタンスが非常に小さくなり、限流電流はさらに増大する。
短絡電流の減少期間では、第１の鉄心２Ｃの磁界Ｈが減少し、飽和境界点ＨＡ７より右側の領域に再び入ると、インダクタンスが大きくなるので、短絡電流は再び抑制される。
図４はこのときの短絡電流が限流された様子を示す図である。この図４から、短絡発生後、短絡電流は大きく抑制されることが分かる。なお、図４の領域Ａは飽和境界点ＨＡ６と飽和境界点ＨＡ７との間の磁気非飽和領域に対応し、領域Ｂは第１の鉄心２Ａの磁界Ｈが飽和境界点ＨＡ７の左側の磁気飽和領域内であるときに対応し、図４の領域Ｃは飽和境界点ＨＡ６と飽和境界点ＨＡ７との間の磁気非飽和領域に対応する。なお、ＨＡ８では領域Ｂでの頂点に対応する。
なお、この実施の形態では、従来の鉄心２Ａ，２Ｂと比較して鉄心２Ｃ，２Ｄの磁路断面積が一様に小さくしたが、第１の鉄心と第２の鉄心とが空間を介して対向した部分のみを円弧状に切り欠くことで鉄心の磁路断面積を小さくするようにしてもよい。
【００２０】
上記構成の限流器４は、図５に示すように開閉器５に直列に接続される。この開閉器５として、例えば気中式配線用遮断器のような気中式開閉器、半導体式開閉器、真空遮断器が用いられる。
これらの内、限流器４の負荷側の開閉器５として気中式開閉器が用いられた場合には、遮断時、気中式開閉器の接点間にアークが発生する。このアークはある時間の間、接点間に膠着した後、駆動される。この膠着している時間Ｔｉは膠着時間と呼ばれる。膠着時間の後、アークは気中式開閉器の内部で発生する磁場により駆動され大きく引き伸ばされ、図６に示すようにアーク電圧（換言するとアーク抵抗）が高くなり、電流が遮断される。
【００２１】
ところで、気中式開閉器の膠着時間は遮断電流変化率（ｄｉ／ｄｔ）の影響を受ける。気中式開閉器では遮断電流変化率が大きい場合、膠着時間が長くなるという現象がある。膠着時間が長くなると、接点からの金属蒸気の放出が多くなるため、遮断性能が大きく低下する。
この実施の形態では、限流器４で遮断電流変化率が小さく抑えられているので、膠着時間が短くなる。その結果、アークは速く駆動され、遮断が容易に行われるので、遮断性能が低い気中式開閉器の適用が可能となる。
なお、この発明は交流回路の短絡電流の抑制に大きな効果を発揮するのは勿論であるが、直流回路の短絡電流の立ち上がり速度の抑制にも大きな効果を発揮することは言うまでもないことである。
【００２２】
なお、コイル３については、図７および図８に示すように、断面形状が矩形状のコイル３Ａであってもよい。
【００２３】
実施の形態２．
図９はこの実施の形態の限流器４が組み込まれた他の例を示す電気回路図である。
この実施の形態では、限流器４の負荷側には複数の開閉器５Ａ，５Ｂ，５Ｃが接続される。このように構成することで、複数の開閉器５Ａ，５Ｂ，５Ｃに対し、限流器４の数は１個で済むので、コンパクト、低コストの限流遮断システムを構築できる。
【００２４】
実施の形態３．
上記各実施の形態では、磁気飽和調整手段として、第１の鉄心２Ｃおよび第２の鉄心２Ｄの磁路断面積を調整したものであったが、この実施の形態では、磁気飽和調整手段としてコイル３の導線の巻数を調整する手段を採用した例である。図１０はこの発明の実施の形態３の限流器における鉄心２Ａ，２ＢのＢ−Ｈ特性図であり、この限流器のＢ−Ｈ特性図は従来のものと同じであるが、第１の鉄心２Ａ、第２の鉄心２Ｂを通る磁束量は導線の巻数が減少した分減少する。
ここで、実線矢印は従来例、点線矢印は実施の形態３のそれぞれの磁界Ｈの値であり、ＨＡ１はコイル３に電流が流れていない場合の第１の鉄心２Ａの磁界Ｈの強さ、ＨＡ２は第１の端子６Ａからコイル３に流れる負荷電流がピーク時での磁界Ｈの強さ、ＨＡ３は第２の端子６Ｂからコイル３に逆方向に流れる負荷電流がピーク時での磁界Ｈの強さである。
コイル３の導線の巻数を小さくしたことで、図１０から分かるように、この実施の形態３の限流器での（ＨＡ１−ＨＡ２）の値、および（ＨＡ１−ＨＡ３）の値はともに、従来のものと比較して小さくなる。
この限流器では、例えばコイル３の第２の端子６Ｂから短絡電流が流れ込むと、磁気飽和していた鉄心２Ａは磁気飽和が解けて、飽和境界点ＨＡ６の左側の領域内で、Ｂ−Ｈ線の傾斜角度が大きい領域に入るために、限流器のインダクタンスが大きくなり短絡電流が抑制される。但し、コイル３の導線の巻数が従来のものと比較して小さくなっているので、限流時のインダクタンスは小さいが、そのインダクタンスは飽和状態におけるインダクタンスよりも格段に大きい。限流時のインダクタンスが小さいことにより、限流電流が大きくなるため、磁気飽和に至る。磁気飽和すると限流器のインダクタンスは非常に小さくなり、限流電流が一定期間突出した、先に説明した図４の波形図が得られる。
【００２５】
実施の形態４．
この実施の形態では、磁気飽和調整手段として、第１の永久磁石１Ａ、第２の永久磁石１Ｂの磁路断面積を小さくする手段を採用した例である。
図１１はこの発明の実施の形態４の限流器における鉄心２Ａ，２ＢのＢ−Ｈ特性図であり、この限流器のＢ−Ｈ特性図は従来のものと同じであるが、第１の永久磁石１Ａ、第２の永久磁石１Ｂの断面積を小さくした分、第１の鉄心２Ａ、第２の鉄心２Ｂを通る磁束量は減少する。
ここで、実線矢印は従来例、点線矢印は実施の形態４のそれぞれの磁界Ｈの値であり、また各記号は図１０と同様である。
この限流器では、例えばコイル３の第２の端子６Ｂから短絡電流が流れ込むと、磁気飽和していた鉄心２Ａは磁気飽和が解けて、飽和境界点ＨＡ６の左側の領域内で、Ｂ−Ｈ線の傾斜角度が大きい領域に入るために、限流器のインダクタンスが大きくなり短絡電流が抑制される。但し、第１の永久磁石１Ａ、第２の永久磁石１Ｂの発生磁束が少ないことにより、限流開始までの時間が速くなる。これに伴い、一旦限流した後の磁気飽和に至るまでの時間が短くなる。磁気飽和すると限流器のインダクタンスは非常に小さくなり、限流電流が一定期間突出した、先に説明した図４の波形図が得られる。
【００２６】
実施の形態５．
この実施の形態では、磁気飽和調整手段として、第１の鉄心、第２の鉄心の材料を例えば電磁軟鉄のような珪素鋼板と比較して磁気的性能が低い材料を用いる手段を採用した例である。
図１２はこの発明の実施の形態５の限流器における鉄心のＢ−Ｈ特性図であり、珪素鋼板を用いた鉄心のＢ−Ｈ特性に対して、この実施の形態の鉄心は、太い破線で示すように、飽和磁束密度が低下し、また磁気非飽和領域での直線の傾きが小さく、磁気飽和領域での直線の傾きが大きい。ここで、実線矢印は従来例、点線矢印は実施の形態５のそれぞれの磁界Ｈの値であり、また各記号は図１０と同様である。
この限流器では、例えばコイル３の第２の端子６Ｂから短絡電流が流れ込むと、磁気飽和していた鉄心２Ｃは磁気飽和が解けて、飽和境界点ＨＡ６の左側の領域内で、Ｂ−Ｈ線の傾斜角度が大きい領域に入るために、限流器のインダクタンスが大きくなり短絡電流が抑制される。但し、鉄心に発生する磁束は少ないので、限流時のインダクタンスは小さいが、このインダクタンスは飽和状態におけるインダクタンスよりも格段に大きい。限流時のインダクタンスが小さいことにより、限流電流が大きくなるので、磁気飽和に至る。磁気飽和すると限流器のインダクタンスは非常に小さくなり、限流電流が一定期間突出した、先に説明した図４の波形図が得られる。
【００２７】
【発明の効果】
以上説明したように、この発明に係る限流器によれば、対向した一対の第１の鉄心および第２の鉄心と、前記第１の鉄心と前記第２の鉄心との間に第１の鉄心および第２の鉄心の磁場を強めるように極性配置されて設けられた第１の永久磁石および第２の永久磁石とから構成された閉磁気回路と、
前記第１の鉄心および前記第２の鉄心の外周に巻回されたコイルとを備え、
前記コイルに電流が流れていないとき、およびコイルに負荷電流が通電中のときには、前記第１の鉄心および前記第２の鉄心は磁気飽和し、前記コイルに短絡電流が流れたときには、前記第１の鉄心および前記第２の鉄心の何れかで磁気飽和が解かれるようになっている限流器であって、
前記閉磁気回路には、前記コイルに前記短絡電流が流れたときにおいて、磁気飽和が解かれた前記第１の鉄心または前記第２の鉄心がコイルに流れる電流の増加に伴い磁気飽和する磁気飽和調整手段が施されているので、限流器の小型化、軽量化が可能となる。
【００２８】
また、この発明に係る限流器によれば、磁気飽和調整手段は、第１の鉄心および第２の鉄心の磁路断面積を調整するものなので、従来のものと比較して第１の鉄心および第２の鉄心の磁路断面積を小さくすることで、限流器の小型化、軽量化が可能となる。
【００２９】
また、この発明に係る限流器によれば、磁気飽和調整手段は、第１の永久磁石および第２の永久磁石の磁路断面積を調整するものなので、従来のものと比較して第１の永久磁石および第２の永久磁石の磁路断面積を小さくすることで、限流器の小型化、軽量化、およびコスト低減が可能となる。
【００３０】
また、この発明に係る限流器によれば、磁気飽和調整手段は、第１の鉄心および第２の鉄心の材質を調整するものなので、低コストの磁気的性能が低い材料を用いることが可能となる。
【００３１】
また、この発明に係る限流器によれば、対向した一対の第１の鉄心および第２の鉄心と、前記第１の鉄心と前記第２の鉄心との間に第１の鉄心および第２の鉄心の磁場を強めるように極性配置されて設けられた第１の永久磁石および第２の永久磁石とから構成された閉磁気回路と、
前記第１の鉄心および前記第２の鉄心の外周に巻回されたコイルを備え、
前記コイルに電流が流れていないとき、およびコイルに負荷電流が通電中のときには、前記第１の鉄心および前記第２の鉄心は磁気飽和し、前記コイルに短絡電流が流れたときには、前記第１の鉄心および前記第２の鉄心の何れかで磁気飽和が解かれるようになっている限流器であって、
前記コイルでは、コイルの導線の巻数を調整することで、前記コイルに前記短絡電流が流れたときにおいて、磁気飽和が解かれた前記第１の鉄心または前記第２の鉄心がコイルに流れる電流の増加に伴い磁気飽和するようになっているので、導線の巻数を従来のものと比較して少なくすることで、限流器の小型化、軽量化、およびコスト低減が可能となる。
【００３２】
また、この発明に係る限流器によれば、アーク電圧発生後にアーク電圧が増大する開閉器が直列に接続されるので、遮断電流が小さな開閉器で大きな電流を限流遮断できる限流遮断システムを構築することができる。
【００３３】
また、この発明に係る限流器によれば、複数の分岐開閉器のそれぞれが限流器に直列に接続されるので、遮断電流が小さな開閉器で大きな電流を限流遮断でき、しかもコンパクト、低コストの限流遮断システムを構築することができる。
【図面の簡単な説明】
【図１】この発明の実施の形態１の限流器の正断面図である。
【図２】図１の限流器の側断面図である。
【図３】図１の限流器の第１の鉄心のＢ−Ｈ特性図である。
【図４】図１の限流器の電流波形図である。
【図５】図１の限流器が組み込まれた電気回路図である。
【図６】図５の限流器のアーク電圧特性図である。
【図７】実施の形態１の限流器の他の例の正断面図である。
【図８】図７の限流器の側断面図である。
【図９】図１の限流器が組み込まれた他の例を示す実施の形態２の電気回路図である。
【図１０】実施の形態３の限流器の第１の鉄心のＢ−Ｈ特性図である。
【図１１】実施の形態４の限流器の第１の鉄心のＢ−Ｈ特性図である。
【図１２】実施の形態５の限流器の第１の鉄心のＢ−Ｈ特性図である。
【図１３】従来の限流器の正断面図である。
【図１４】図１３の限流器の側断面図である。
【図１５】図１３の限流器の第１の鉄心のＢ−Ｈ特性図である。
【図１６】図１３の限流器の第２の鉄心のＢ−Ｈ特性図である。
【図１７】図９の限流器の電流波形図である。
【符号の説明】
１Ａ　第１の永久磁石、１Ｂ　第２の永久磁石、３，３Ａ　コイル、４　限流器、５　開閉器、２Ａ，２Ｃ　第１の鉄心、２Ｂ，２Ｄ　第２の鉄心。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a current limiter for suppressing an overcurrent generated due to a short circuit accident of an electric circuit or the like.
[0002]
[Prior art]
FIG. 13 is a front sectional view of a current limiter similar to the current limiter (Japanese Patent Application No. 2000-303450) filed by the present applicant, and FIG. 14 is a side sectional view of the current limiter of FIG.
In the drawing, 1A is a prismatic first permanent magnet whose upper surface is magnetized to the N pole and the lower surface is magnetized to the S pole. 1B is opposed to the first permanent magnet 1A and the upper surface is magnetized to the S pole and the lower surface is magnetized to the N pole. The magnetized prism-shaped second permanent magnets 2A, 2B are opposed to each other, and the first and second cores are made of a silicon steel plate sandwiching the first permanent magnet 1A and the second permanent magnet 1B. It is. Since the first and second permanent magnets 1A and 1B are magnetized, the magnetic fields created in the first and second iron cores 2A and 2B are strong, but if one of the permanent magnets 1A and 1B has the opposite polarity. Then, the magnetic field created in the iron cores 2A and 2B is weakened. Here, the first permanent magnet 1A, the second permanent magnet 1B, the first iron core 2A, and the second iron core 2B constitute a closed magnetic circuit.
Reference numeral 3 denotes a coil in which a conductive wire is wound outside the first and second iron cores 2A and 2B in a single layer state, 6A denotes a first terminal of the coil 3, and 6B denotes a second terminal of the coil 3. The coil 3 may be configured by winding a conductive wire in a multilayer state. When no current flows through the coil 3, the first and second iron cores 2A and 2B are magnetically saturated by the first and second permanent magnets 1A and 1B.
[0003]
FIG. 15 is a BH characteristic diagram of the first core 2A, and FIG. 16 is a BH characteristic diagram of the second core 2B. H indicates the magnetic field strength and B indicates the magnetic flux density.
This current limiter is configured such that when no current flows through the coil 3, the strength of the magnetic field H of the first iron core 2A is HA1, and the strength of the magnetic field H of the second iron core 2B is HB1. . When the intensity of the magnetic field H of the first iron core 2A is HA1, the first iron core 2A is in a magnetically saturated state as can be seen from FIG. 15, and when the H of the iron core 2B is HB1, the iron core 2B is shown in FIG. As can be seen from the above, the current limiter has a small inductance because it is in a magnetic saturation state.
When an AC load current flows from the first terminal 6A of the coil 3, a magnetic flux is generated in the coil 3, the first core 2A is further magnetically saturated, and the magnetic field of the first core 2A at the peak of the load current. The strength of H moves to HA2. On the other hand, the second core 2B is demagnetized, and the absolute value of the magnetic field H of the second core 2B decreases to HB2 at the peak of the load current, but is in the saturation region.
[0004]
Next, when a load current flows from the second terminal 6B of the coil 3, the first iron core 2A is demagnetized, and the magnetic field H decreases to HA3 at the time of the current peak, but is in the saturation region. The magnetic field H of the second iron core 2B becomes HB3 at the time of the current peak, and the second iron core 2B is further magnetically saturated.
As described above, when the load current is supplied, the first iron core 2A and the second iron core 2B are magnetically saturated regardless of the current flowing in either direction, and thus the inductance of the current limiter is in a low state.
[0005]
Next, a case where an excessive current such as a short-circuit current flows through the coil 3 will be described.
When a short-circuit current flows from the first terminal 6A of the coil 3, a large magnetic flux is generated in the coil 3, the magnetic field H of the first core 2A becomes HA4 at the time of a current peak, and the first core 2A is further saturated. I do. On the other hand, the intensity of the magnetic field H of the second iron core 2B is HB4 in the region on the right side of HB6, which is the saturation boundary point of the magnetic saturation region.
In the second iron core 2B, when the magnetic field H enters the region on the right side of HB6, the magnetic saturation is released, and the magnetic flux H enters the region where the inclination angle of the BH line is large, so that the inductance of the current limiter increases and the short-circuit current is suppressed. You.
[0006]
Next, when a short-circuit current flows from the second terminal 6B of the coil 3, the magnetic field H of the second iron core 2B becomes HB5 at the time of the current peak, and the second iron core 2B is further saturated. On the other hand, the strength of the magnetic field H of the first iron core 2A is HA5 in the area on the left side of HA6 which is the saturation boundary point of the magnetic saturation area.
In the second iron core 2A, when the magnetic field H enters the area on the left side of the HA 6, magnetic saturation is released, and the magnetic field H enters the area where the inclination angle of the BH line is large, so that the inductance of the current limiter increases and the short-circuit current is suppressed. You.
[0007]
As described above, when the short-circuit current flows through the coil 3, the magnetic saturation of one of the iron cores 2A and 2B is released irrespective of the current flowing in either direction, so that the inductance of the current limiter becomes high, and the short-circuit current is reduced. Be suppressed. FIG. 17 is a diagram showing a state where the short-circuit current is limited by the current limiting device.
[0008]
[Problems to be solved by the invention]
In the current limiting device having the above-described configuration, for example, even when a short-circuit current includes a DC component, a high inductance state is ensured to suppress the short-circuit current. In the iron core 2B, the cross-sectional area in the direction perpendicular to the magnetic path must be increased, and in order to magnetically saturate the iron cores 2A and 2B having the large cross-sectional area, the cross-sectional areas of the permanent magnets 1A and 1B are also large. However, there is a problem in that the overall size is increased and the weight is increased.
[0009]
SUMMARY OF THE INVENTION An object of the present invention is to solve the above-described problems, and an object of the present invention is to obtain a current limiting device that can be reduced in size and weight.
[0010]
[Means for Solving the Problems]
The current limiter according to the present invention includes a pair of opposed first and second iron cores, and a magnetic field between the first and second iron cores between the first and second iron cores. A closed magnetic circuit composed of a first permanent magnet and a second permanent magnet provided in a polar arrangement so as to enhance
A coil wound around an outer periphery of the first core and the second core;
When no current is flowing through the coil and when a load current is flowing through the coil, the first core and the second core are magnetically saturated, and when a short-circuit current flows through the coil, the first core is A current limiter wherein magnetic saturation is solved in any one of the iron core and the second iron core,
In the closed magnetic circuit, when the short-circuit current flows through the coil, the first core or the second core whose magnetic saturation has been released has a magnetic saturation that is magnetically saturated with an increase in current flowing through the coil. Adjusting means are provided.
[0011]
In the current limiter according to the present invention, the magnetic saturation adjusting means adjusts a magnetic path cross-sectional area of the first iron core and the second iron core.
[0012]
In the current limiter according to the present invention, the magnetic saturation adjusting means adjusts a magnetic path cross-sectional area of the first permanent magnet and the second permanent magnet.
[0013]
In the current limiter according to the present invention, the magnetic saturation adjusting means adjusts the material of the first iron core and the second iron core.
[0014]
The current limiter according to the present invention includes a pair of opposed first and second iron cores, and a magnetic field between the first and second iron cores between the first and second iron cores. A closed magnetic circuit composed of a first permanent magnet and a second permanent magnet provided in a polar arrangement so as to enhance
A coil wound around an outer periphery of the first core and the second core;
When no current is flowing through the coil and when a load current is flowing through the coil, the first core and the second core are magnetically saturated, and when a short-circuit current flows through the coil, the first core is A current limiter wherein magnetic saturation is solved in any one of the iron core and the second iron core,
In the coil, by adjusting the number of turns of the conductor of the coil, when the short-circuit current flows through the coil, the first core or the second core whose magnetic saturation has been released has a current flowing through the coil. Magnetic saturation occurs with the increase.
[0015]
In the current limiter according to the present invention, a switch whose arc voltage increases after the arc voltage is generated is connected in series.
[0016]
In the current limiter according to the present invention, each of the plurality of branch switches is connected in series to the current limiter.
[0017]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described. The same or corresponding members as those of the related art will be denoted by the same reference numerals.
Embodiment 1 FIG.
FIG. 1 is a front sectional view of the current limiting device according to Embodiment 1 of the present invention, and FIG. 2 is a side sectional view of the current limiting device of FIG.
In the drawing, 1A is a prismatic first permanent magnet whose upper surface is magnetized to the N pole and the lower surface is magnetized to the S pole. 1B is opposed to the first permanent magnet 1A and the upper surface is magnetized to the S pole and the lower surface is magnetized to the N pole. The magnetized prism-shaped second permanent magnets 2C, 2D are opposed to each other, and the first and second cores are made of a silicon steel plate sandwiching the first permanent magnet 1A and the second permanent magnet 1B. It is. Since the first and second permanent magnets 1A and 1B are magnetized, the magnetic fields created in the first and second iron cores 2C and 2D are strong, but if one of the permanent magnets 1A and 1B has the opposite polarity. Then, the magnetic field created in the iron cores 2C and 2D is weakened. Here, the first permanent magnet 1A, the second permanent magnet 1B, the first iron core 2C, and the second iron core 2D constitute a closed magnetic circuit.
Reference numeral 3 denotes a coil in which a conductive wire is wound outside the first and second iron cores 2C and 2D in a single-layer state, 6A denotes a first terminal of the coil 3, and 6B denotes a second terminal of the coil 3. The coil 3 may be configured by winding a conductive wire in a multilayer state.
[0018]
In this current limiter, when a short-circuit current flows through the coil 3, the magnetic saturation is adjusted such that the first iron core 2 C or the second iron core 2 D whose magnetic saturation has been released is magnetically saturated with an increase in the current flowing through the coil 3. Means have been applied. Specifically, the magnetic cores 2C and 2D have a smaller magnetic path cross-sectional area than the conventional cores 2A and 2B.
FIG. 3 is a BH characteristic diagram of a first iron core 2A of the related art and a first iron core 2C of the first embodiment. Although the characteristic diagrams of both are the same, a first iron core 2C and a second iron core are shown. The amount of magnetic flux passing through 2D is reduced as compared with the conventional one by the reduced cross-sectional area. Here, the solid arrow indicates the value of the magnetic field H of the conventional example, the dotted arrow indicates the value of the magnetic field H of the first embodiment, and HA1 indicates the strength of the magnetic field H of the first iron core 2C when no current flows through the coil 3. HA2 is the intensity of the magnetic field H when the load current flowing from the first terminal 6A to the coil 3 is at a peak, and HA3 is the intensity of the magnetic field H when the load current flowing from the second terminal 6B to the coil 3 in the reverse direction is at a peak. Strength.
[0019]
As can be seen from FIG. 3, by reducing the cross-sectional area of iron cores 2C and 2D, the value of (HA1-HA2) and the value of (HA1-HA3) in the current limiter of the first embodiment are both: It is larger than the conventional one.
In this current limiter, for example, when a short-circuit current flows from the second terminal 6B of the coil 3, the magnetically saturated first iron core 2C is released from magnetic saturation, and B Since the inclination angle of the -H line is in a large range, the inductance of the current limiter increases, and the short-circuit current is suppressed. However, since the cross-sectional area of the iron cores 2C and 2D is smaller than that of the conventional one, the inductance at the time of current limiting is small, but the inductance is much larger than the inductance in the saturated state. Since the current limiting current is increased due to the small inductance at the time of the current limiting, the current reaches the saturation boundary point HA7. When magnetic saturation occurs, the inductance of the current limiter becomes very small, and the current limit current further increases.
In the short-circuit current decreasing period, when the magnetic field H of the first iron core 2C decreases and enters the region on the right side of the saturation boundary point HA7 again, the inductance increases, and the short-circuit current is suppressed again.
FIG. 4 is a diagram showing a state where the short-circuit current is limited at this time. It can be seen from FIG. 4 that after the occurrence of the short circuit, the short circuit current is greatly suppressed. 4 corresponds to a magnetically unsaturated region between the saturation boundary point HA6 and the saturation boundary point HA7, and a region B corresponds to the magnetic saturation of the first iron core 2A on the left side of the saturation boundary point HA7. 4 corresponds to a magnetically unsaturated region between the saturated boundary point HA6 and the saturated boundary point HA7. In HA8, it corresponds to the vertex in region B.
In this embodiment, the magnetic cores 2C and 2D have a uniformly smaller magnetic path cross-sectional area than the conventional iron cores 2A and 2B. However, the first iron core and the second iron core are interposed through a space. The magnetic path cross-sectional area of the iron core may be reduced by cutting out only the opposing portion in an arc shape.
[0020]
The current limiter 4 having the above configuration is connected in series to the switch 5 as shown in FIG. As the switch 5, for example, an air switch, a semiconductor switch, or a vacuum circuit breaker such as a circuit breaker for aerial wiring is used.
When an aerial switch is used as the switch 5 on the load side of the current limiter 4, an arc is generated between the contacts of the aerial switch at the time of interruption. The arc is driven for a period of time after stagnation between the contacts. This sticking time Ti is called the sticking time. After the stagnation time, the arc is driven and extended greatly by the magnetic field generated inside the submersible switch, and as shown in FIG. 6, the arc voltage (in other words, the arc resistance) increases, and the current is interrupted.
[0021]
By the way, the stagnation time of the aerial switch is affected by the breaking current change rate (di / dt). In the case of an aerial switch, there is a phenomenon that the stagnation time becomes longer when the breaking current change rate is large. If the sticking time is long, the release of metal vapor from the contacts increases, so that the blocking performance is greatly reduced.
In this embodiment, since the breaking current change rate is suppressed small by the current limiter 4, the sticking time is shortened. As a result, the arc is driven quickly and the breaking is easily performed, so that an aerial switch having a low breaking performance can be applied.
It is needless to say that the present invention not only exerts a great effect in suppressing the short-circuit current of the AC circuit, but also exerts a great effect in suppressing the rising speed of the short-circuit current in the DC circuit.
[0022]
As shown in FIGS. 7 and 8, the coil 3A may be a coil 3A having a rectangular cross section.
[0023]
Embodiment 2 FIG.
FIG. 9 is an electric circuit diagram showing another example in which the current limiter 4 of this embodiment is incorporated.
In this embodiment, a plurality of switches 5A, 5B, 5C are connected to the load side of the current limiter 4. With such a configuration, only one current limiter 4 is required for the plurality of switches 5A, 5B, and 5C, so that a compact and low-cost current-limit cutoff system can be constructed.
[0024]
Embodiment 3 FIG.
In each of the above embodiments, the magnetic saturation cross-sectional areas of the first iron core 2C and the second iron core 2D are adjusted as the magnetic saturation adjusting means. In this embodiment, however, a coil is used as the magnetic saturation adjusting means. This is an example in which means for adjusting the number of turns of the conductive wire of No. 3 is adopted. FIG. 10 is a BH characteristic diagram of iron cores 2A and 2B in the current limiting device according to Embodiment 3 of the present invention. The BH characteristic diagram of this current limiting device is the same as that of the prior art, The amount of magnetic flux passing through the iron core 2A and the second iron core 2B is reduced by the decrease in the number of turns of the conductor.
Here, the solid arrow indicates the value of the magnetic field H of the conventional example, the dotted arrow indicates the value of the magnetic field H of the third embodiment, and HA1 indicates the intensity of the magnetic field H of the first iron core 2A when no current flows through the coil 3. HA2 is the intensity of the magnetic field H when the load current flowing from the first terminal 6A to the coil 3 is at a peak, and HA3 is the intensity of the magnetic field H when the load current flowing from the second terminal 6B to the coil 3 in the reverse direction is at a peak. Strength.
As can be seen from FIG. 10, by reducing the number of turns of the conductor of the coil 3, both the value of (HA1−HA2) and the value of (HA1−HA3) in the current limiter of the third embodiment are the same as those of the prior art. Is smaller than that of
In this current limiter, for example, when a short-circuit current flows from the second terminal 6B of the coil 3, the magnetic core 2A, which has been magnetically saturated, is released from magnetic saturation, and BH in the region on the left side of the saturation boundary HA6. Since the line enters the region where the inclination angle of the line is large, the inductance of the current limiter increases and the short-circuit current is suppressed. However, since the number of turns of the conductive wire of the coil 3 is smaller than that of the conventional one, the inductance at the time of current limit is small, but the inductance is much larger than the inductance in the saturated state. Since the current limiting current becomes large due to the small inductance at the time of current limiting, magnetic saturation occurs. When the magnetic saturation occurs, the inductance of the current limiter becomes very small, and the waveform diagram of FIG.
[0025]
Embodiment 4 FIG.
This embodiment is an example in which a means for reducing the magnetic path cross-sectional area of the first permanent magnet 1A and the second permanent magnet 1B is employed as the magnetic saturation adjusting means.
FIG. 11 is a BH characteristic diagram of iron cores 2A and 2B in the current limiter according to the fourth embodiment of the present invention. The amount of magnetic flux passing through the first iron core 2A and the second iron core 2B is reduced by reducing the cross-sectional area of the permanent magnet 1A and the second permanent magnet 1B.
Here, the solid arrows indicate the values of the magnetic field H of the conventional example, the dotted arrows indicate the values of the respective magnetic fields H of the fourth embodiment, and the symbols are the same as in FIG.
In this current limiter, for example, when a short-circuit current flows from the second terminal 6B of the coil 3, the magnetic core 2A, which has been magnetically saturated, is released from magnetic saturation, and BH in the region on the left side of the saturation boundary HA6. Since the line enters the region where the inclination angle of the line is large, the inductance of the current limiter increases and the short-circuit current is suppressed. However, since the magnetic fluxes generated by the first permanent magnet 1A and the second permanent magnet 1B are small, the time until the start of the current limiting is shortened. Along with this, the time required to reach magnetic saturation after the current is once limited is shortened. When the magnetic saturation occurs, the inductance of the current limiter becomes very small, and the waveform diagram of FIG.
[0026]
Embodiment 5 FIG.
In this embodiment, as the magnetic saturation adjusting means, an example in which the material of the first iron core and the second iron core is made of a material whose magnetic performance is lower than that of a silicon steel sheet such as electromagnetic soft iron is adopted. is there.
FIG. 12 is a BH characteristic diagram of the iron core in the current limiter according to the fifth embodiment of the present invention. In contrast to the BH characteristic of the iron core using a silicon steel plate, the iron core according to the fifth embodiment has a thick broken line. As shown by, the saturation magnetic flux density decreases, the inclination of the straight line in the magnetically unsaturated region is small, and the inclination of the straight line in the magnetically saturated region is large. Here, the solid arrows indicate the values of the magnetic field H of the conventional example, the dotted arrows indicate the values of the respective magnetic fields H of the fifth embodiment, and the symbols are the same as in FIG.
In this current limiter, for example, when a short-circuit current flows from the second terminal 6B of the coil 3, the magnetic core 2C, which has been magnetically saturated, is released from magnetic saturation, and BH falls within a region on the left side of the saturation boundary point HA6. Since the line enters the region where the inclination angle of the line is large, the inductance of the current limiter increases and the short-circuit current is suppressed. However, since the magnetic flux generated in the iron core is small, the inductance at the time of current limiting is small, but this inductance is much larger than the inductance in the saturated state. Since the current limiting current becomes large due to the small inductance at the time of current limiting, magnetic saturation occurs. When the magnetic saturation occurs, the inductance of the current limiter becomes very small, and the waveform diagram of FIG.
[0027]
【The invention's effect】
As described above, according to the current limiter according to the present invention, the first core and the second core opposed to each other, and the first core between the first core and the second core. A closed magnetic circuit composed of a first permanent magnet and a second permanent magnet arranged in a polar arrangement so as to enhance the magnetic field of the iron core and the second iron core;
A coil wound around the outer periphery of the first core and the second core,
When no current is flowing through the coil and when a load current is flowing through the coil, the first core and the second core are magnetically saturated, and when a short-circuit current flows through the coil, the first core is A current limiter wherein magnetic saturation is solved in any one of the iron core and the second iron core,
In the closed magnetic circuit, when the short-circuit current flows through the coil, the first core or the second core whose magnetic saturation has been released has a magnetic saturation that is magnetically saturated with an increase in current flowing through the coil. Since the adjusting means is provided, the current limiter can be reduced in size and weight.
[0028]
According to the current limiter of the present invention, the magnetic saturation adjusting means adjusts the magnetic path cross-sectional areas of the first iron core and the second iron core. By reducing the magnetic path cross-sectional area of the second iron core, the current limiter can be reduced in size and weight.
[0029]
According to the current limiter according to the present invention, the magnetic saturation adjusting means adjusts the magnetic path cross-sectional areas of the first permanent magnet and the second permanent magnet. By reducing the magnetic path cross-sectional areas of the permanent magnet and the second permanent magnet, it is possible to reduce the size, weight, and cost of the current limiter.
[0030]
Further, according to the current limiter according to the present invention, the magnetic saturation adjusting means adjusts the materials of the first iron core and the second iron core, so that a low-cost material having low magnetic performance can be used. It becomes.
[0031]
Further, according to the current limiter according to the present invention, the first iron core and the second iron core are provided between the pair of the first iron core and the second iron core opposed to each other, and the first iron core and the second iron core. A closed magnetic circuit composed of a first permanent magnet and a second permanent magnet provided in a polar arrangement so as to increase the magnetic field of the iron core;
A coil wound around an outer periphery of the first core and the second core;
When no current is flowing through the coil and when a load current is flowing through the coil, the first core and the second core are magnetically saturated, and when a short-circuit current flows through the coil, the first core is A current limiter wherein magnetic saturation is solved in any one of the iron core and the second iron core,
In the coil, by adjusting the number of turns of the conductor of the coil, when the short-circuit current flows through the coil, the first core or the second core whose magnetic saturation has been released has a current flowing through the coil. Since magnetic saturation is caused by the increase, the number of turns of the conductor is reduced as compared with the conventional one, so that the current limiter can be reduced in size, weight, and cost.
[0032]
Further, according to the current limiter according to the present invention, the switches whose arc voltage increases after the arc voltage is generated are connected in series, so that the current limiter can cut off a large current with a switch having a small breaking current. Can be constructed.
[0033]
Further, according to the current limiter according to the present invention, since each of the plurality of branch switches is connected in series with the current limiter, a large current can be subjected to current limit interruption with a switch having a small interruption current, and furthermore, compactness is achieved. It is possible to construct a low-cost current limiting circuit system.
[Brief description of the drawings]
FIG. 1 is a front sectional view of a current limiter according to Embodiment 1 of the present invention.
FIG. 2 is a side sectional view of the current limiter of FIG. 1;
FIG. 3 is a BH characteristic diagram of a first iron core of the current limiter of FIG. 1;
FIG. 4 is a current waveform diagram of the current limiter of FIG. 1;
FIG. 5 is an electric circuit diagram incorporating the current limiter of FIG. 1;
6 is an arc voltage characteristic diagram of the current limiter of FIG.
FIG. 7 is a front sectional view of another example of the current limiter of the first embodiment.
FIG. 8 is a side sectional view of the current limiter of FIG. 7;
FIG. 9 is an electric circuit diagram of a second embodiment showing another example in which the current limiter of FIG. 1 is incorporated.
FIG. 10 is a BH characteristic diagram of a first iron core of the current limiter according to the third embodiment.
FIG. 11 is a BH characteristic diagram of a first iron core of the current limiter according to the fourth embodiment.
FIG. 12 is a BH characteristic diagram of a first iron core of the current limiter according to the fifth embodiment.
FIG. 13 is a front sectional view of a conventional current limiter.
FIG. 14 is a side sectional view of the current limiter of FIG. 13;
FIG. 15 is a BH characteristic diagram of a first iron core of the current limiter of FIG. 13;
FIG. 16 is a BH characteristic diagram of a second iron core of the current limiter of FIG.
FIG. 17 is a current waveform diagram of the current limiter of FIG. 9;
[Explanation of symbols]
1A 1st permanent magnet, 1B 2nd permanent magnet, 3,3A coil, 4 current limiter, 5 switch, 2A, 2C 1st core, 2B, 2D 2nd core.

Claims

A pair of opposing first and second iron cores, and polar arrangements are provided between the first and second iron cores so as to enhance the magnetic field of the first and second iron cores. A closed magnetic circuit composed of a first permanent magnet and a second permanent magnet
A coil wound around an outer periphery of the first core and the second core;
When no current is flowing through the coil and when a load current is flowing through the coil, the first core and the second core are magnetically saturated, and when a short-circuit current flows through the coil, the first core is A current limiter wherein magnetic saturation is solved in any one of the iron core and the second iron core,
In the closed magnetic circuit, when the short-circuit current flows through the coil, the first core or the second core whose magnetic saturation has been released has a magnetic saturation that is magnetically saturated with an increase in current flowing through the coil. Current limiter with adjusting means.

The current limiter according to claim 1, wherein the magnetic saturation adjustment means adjusts a magnetic path cross-sectional area of the first iron core and the second iron core.

2. The current limiter according to claim 1, wherein the magnetic saturation adjustment unit adjusts a magnetic path cross-sectional area of the first permanent magnet and the second permanent magnet. 3.

2. The current limiter according to claim 1, wherein the magnetic saturation adjustment unit adjusts a material of the first core and the second core. 3.

A pair of opposing first and second iron cores, and polar arrangements are provided between the first and second iron cores so as to enhance the magnetic field of the first and second iron cores. A closed magnetic circuit composed of a first permanent magnet and a second permanent magnet
A coil wound around an outer periphery of the first core and the second core;
When no current is flowing through the coil and when a load current is flowing through the coil, the first core and the second core are magnetically saturated, and when a short-circuit current flows through the coil, the first core is A current limiter wherein magnetic saturation is solved in any one of the iron core and the second iron core,
In the coil, by adjusting the number of turns of the conductor of the coil, when the short-circuit current flows through the coil, the first core or the second core whose magnetic saturation has been released has a current flowing through the coil. A current limiter that is magnetically saturated with the increase.

The current limiter according to any one of claims 1 to 5, wherein a switch that increases the arc voltage after the arc voltage is generated is connected in series.

The current limiter according to any one of claims 1 to 6, wherein each of the plurality of branch switches is connected in series to the current limiter.