JPH09233692A - Superconuctive current limiter - Google Patents
Superconuctive current limiterInfo
- Publication number
- JPH09233692A JPH09233692A JP8032292A JP3229296A JPH09233692A JP H09233692 A JPH09233692 A JP H09233692A JP 8032292 A JP8032292 A JP 8032292A JP 3229296 A JP3229296 A JP 3229296A JP H09233692 A JPH09233692 A JP H09233692A
- Authority
- JP
- Japan
- Prior art keywords
- current limiting
- superconducting
- limiting element
- current
- speed switch
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 230000000670 limiting effect Effects 0.000 claims abstract description 172
- 238000010791 quenching Methods 0.000 claims abstract description 30
- 239000003990 capacitor Substances 0.000 claims description 17
- 230000000171 quenching effect Effects 0.000 claims description 8
- 239000002887 superconductor Substances 0.000 description 12
- 238000010586 diagram Methods 0.000 description 8
- 230000004907 flux Effects 0.000 description 8
- 238000000034 method Methods 0.000 description 7
- 239000003507 refrigerant Substances 0.000 description 7
- 230000004044 response Effects 0.000 description 7
- 238000001816 cooling Methods 0.000 description 6
- 230000008859 change Effects 0.000 description 4
- 239000004020 conductor Substances 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 4
- 238000009834 vaporization Methods 0.000 description 4
- 230000008016 vaporization Effects 0.000 description 4
- 238000001514 detection method Methods 0.000 description 3
- 229910052734 helium Inorganic materials 0.000 description 3
- 239000001307 helium Substances 0.000 description 3
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium atom Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 3
- 238000012423 maintenance Methods 0.000 description 3
- 230000000630 rising effect Effects 0.000 description 3
- 230000009471 action Effects 0.000 description 2
- 230000003111 delayed effect Effects 0.000 description 2
- 238000013461 design Methods 0.000 description 2
- 239000007788 liquid Substances 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 230000001052 transient effect Effects 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- XHCLAFWTIXFWPH-UHFFFAOYSA-N [O-2].[O-2].[O-2].[O-2].[O-2].[V+5].[V+5] Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[V+5].[V+5] XHCLAFWTIXFWPH-UHFFFAOYSA-N 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 230000006698 induction Effects 0.000 description 1
- 230000007257 malfunction Effects 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 230000035515 penetration Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229910001935 vanadium oxide Inorganic materials 0.000 description 1
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E40/00—Technologies for an efficient electrical power generation, transmission or distribution
- Y02E40/60—Superconducting electric elements or equipment; Power systems integrating superconducting elements or equipment
Landscapes
- Containers, Films, And Cooling For Superconductive Devices (AREA)
- Emergency Protection Circuit Devices (AREA)
Abstract
Description
【０００１】[0001]
【発明の属する技術分野】本発明は、交流電路に生じる
事故電流を抑制する超電導限流器に関し、特に定常時損
失と限流時損失の双方を低減するための技術に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting fault current limiter for suppressing a fault current generated in an AC electric circuit, and more particularly to a technique for reducing both steady-state loss and current-limiting loss.
【０００２】[0002]
【従来の技術】配電線等の交流電路に３相短絡や地絡事
故が発生すると数十ｋＡにも及ぶ事故電流が流れ系統及
び機器に大きなダメージを与えてしまう。このような事
故電流を瞬時に検出し抑制するための限流技術の一つ
に、最近超電導を応用したものが開発されている。図８
は、その代表的従来技術の構成と適用回路の一例を示し
ている（特開平２−１６８５２５号公報）。同図におい
て２１は電源、２２は遮断器、２３は超電導限流器、２
３ａは超電導限流コイル、２３ｂ，２３ｃは超電導のト
リガコイル、２３ｄはスイッチ、２３ｇはクエンチセン
サ、２４は負荷、２５は回路の全電流を検出するための
変流器、２６はトリガコイル２３ｂ，２３ｃのループ電
流を検出するための変流器、２７は制御電源、２８はル
ープ電流位相検出回路、３０はトリガコイル電圧位相検
出回路、２９はトリガコイル電圧位相検出回路３０を主
回路に接離するためのスイッチ、３１はトリガコイル２
３ｂ，２３ｃの電流と電圧の位相差を比較検出する位相
比較器である。2. Description of the Related Art When a three-phase short circuit or a ground fault occurs in an AC circuit such as a distribution line, a fault current of several tens of kA flows, causing serious damage to systems and equipment. Recently, superconductivity has been developed as one of current limiting techniques for instantaneously detecting and suppressing such a fault current. FIG.
Shows an example of the configuration and the application circuit of the typical prior art (Japanese Patent Laid-Open No. 2-168525). In the figure, 21 is a power source, 22 is a circuit breaker, 23 is a superconducting fault current limiter, 2
3a is a superconducting current limiting coil, 23b and 23c are superconducting trigger coils, 23d is a switch, 23g is a quench sensor, 24 is a load, 25 is a current transformer for detecting the total current of the circuit, 26 is a trigger coil 23b, A current transformer for detecting a loop current of 23c, 27 is a control power supply, 28 is a loop current phase detection circuit, 30 is a trigger coil voltage phase detection circuit, and 29 is a trigger coil voltage phase detection circuit 30 which is connected to or disconnected from the main circuit. Switch for operating, 31 is the trigger coil 2
3b and 23c are phase comparators for comparing and detecting the phase difference between current and voltage.
【０００３】この超電導限流器の動作を簡単に説明す
る。定常時、回路電流は無誘導で超電導（抵抗零）のト
リガコイル２３ｂ，２３ｃ側を流れ、正常に負荷２４へ
給電され続ける。次に負荷２４が短絡するなどして、過
大な事故電流が回路に流れ、その値がトリガコイル２３
ｂ，２３ｃを構成している超電導線の臨界電流値に達す
ると、トリガコイル２３ｂ，２３ｃがクエンチして高抵
抗体に転移する。その結果、事故電流は抑制され、トリ
ガコイル２３ｂ，２３ｃよりインピーダンスの低い超電
導限流コイル２３ａ側へ転流していく。この間、トリガ
コイル２３ｂ，２３ｃは常電導体となっているので、発
熱して冷媒を消費し続けるのと同時に超電導線の温度も
上昇することになる。スイッチ２３ｄは、トリガコイル
２３ｂ，２３ｃ側の電流が超電導限流コイル２３ａ側へ
転流した直後に開極して冷媒の蒸発を抑制すると同時
に、トリガコイル２３ｂ，２３ｃの冷却速度を速めて次
の事故発生に対応できるようにトリガコイル２３ｂ，２
３ｃの超電導復帰を助ける。トリガコイル２３ｂ，２３
ｃの超電導復帰は、各位相検出器２８，３０とその位相
比較器３１によって検出され、系統の事故が復旧したこ
と及びトリガコイル２３ｂ，２３ｃが超電導復帰したこ
との２条件が揃うとスイッチ２３ｄが閉入されて定常状
態に復帰できる。The operation of the superconducting current limiter will be briefly described. At regular times, the circuit current flows through the superconducting (zero resistance) trigger coils 23b and 23c side without induction, and the power is continuously supplied to the load 24 normally. Next, when the load 24 is short-circuited or the like, an excessive accident current flows in the circuit, and its value is the trigger coil 23.
When the critical current value of the superconducting wire forming b and 23c is reached, the trigger coils 23b and 23c are quenched and transferred to a high resistance body. As a result, the fault current is suppressed and commutated to the superconducting current limiting coil 23a side, which has a lower impedance than the trigger coils 23b and 23c. During this time, since the trigger coils 23b and 23c are normal conductors, the temperature of the superconducting wire rises as the heat is generated and the refrigerant is continuously consumed. The switch 23d is opened immediately after the current on the trigger coil 23b, 23c side is commutated to the superconducting current limiting coil 23a side to suppress the evaporation of the refrigerant, and at the same time, accelerates the cooling rate of the trigger coils 23b, 23c. Trigger coils 23b, 2 so that an accident can be dealt with
3c helps the superconductivity return. Trigger coil 23b, 23
The superconducting return of c is detected by the phase detectors 28 and 30 and the phase comparator 31 thereof, and the switch 23d is turned on when two conditions are satisfied, that is, the system fault is restored and the trigger coils 23b and 23c are returned to the superconducting state. It can be closed and returned to a steady state.
【０００４】[0004]
【発明が解決しようとする課題】以上、従来の超電導限
流器の構成と作用について一例を示したが、この種の超
電導限流器は、動作速度が極めて速く、短絡電流のよう
な急峻な立ち上がりをもつ過電流に対しても第１波から
限流できる優れた特性を有する反面、次のような課題も
併せ持っている。An example of the structure and operation of the conventional superconducting fault current limiter has been shown above. However, this type of superconducting fault current limiter has an extremely high operating speed and a sharp current such as a short circuit current. Although it has excellent characteristics that it can limit the rising current from the first wave, it also has the following problems.
【０００５】まず、この種の超電導限流器は、超電導体
をクエンチさせる方式のため、限流動作時（クエンチ）
にかなりのジュール損失Ｐｊが発生する。その値はトリ
ガコイルのクエンチ抵抗値Ｒｑが一定であれば、電源電
圧の２乗に比例する。[0005] First, this type of superconducting current limiter uses a method of quenching the superconductor.
Causes a considerable Joule loss Pj. If the quench resistance value Rq of the trigger coil is constant, its value is proportional to the square of the power supply voltage.
【０００６】[0006]
【数１】 Ｐｊ＝（Ｖ2 ／Ｒｑ）・ｔ （Ｊ） …（１） ｔ：クエンチ発生後の通電時間（ｓｅｃ） したがって、回路電圧が高くなるほどクエンチ時の発生
損失が増大し、超電導体を冷却している冷媒の消費（気
化）量も増大していく。一例として、６．６ｋＶ回路に
生じる短絡電流を、クエンチ抵抗値が１０Ωのトリガコ
イルで１サイクル（２０ｍｓｅｃ）間限流したとすれ
ば、その時の発生損失は（１）式より、 Ｐｊ＝（Ｖ2 ／Ｒｑ）・ｔ ＝（６６００2 ／１０）・０．０２ ＝４３５６０ （Ｊ） となり、かりに冷媒が液体ヘリウムであれば約１７リッ
トルもの液体が瞬時に気化する。気化したヘリウムは、
数百倍の体積に膨張するため、超電導限流器が収納され
ているクライオスタットは、この時の内圧に耐えるよう
に大きくて強固なものにするか、あるいは気化ヘリウム
を外部に放出するかの手段が必要になり、種々のデメリ
ットを生じてしまうことになる。Pj = (V 2 / Rq) · t (J) (1) t: energization time after occurrence of quench (sec) Therefore, as the circuit voltage increases, the loss generated during quench increases, and the superconductor The amount of consumption (vaporization) of the refrigerant that is cooling the air also increases. As an example, if the short-circuit current generated in the 6.6 kV circuit is limited by a trigger coil having a quench resistance value of 10 Ω for one cycle (20 msec), the generated loss at that time is expressed by Pj = (V 2 / Rq) · t = ( 6600 2/10) · 0.02 = 43560 (J) , and the even is a liquid Assuming about 17 liters if the refrigerant is a liquid helium vaporizes instantly. The vaporized helium is
Because it expands to several hundred times the volume, the cryostat that houses the superconducting fault current limiter must be large and strong to withstand the internal pressure at this time, or a means to release vaporized helium to the outside. Is required, which causes various disadvantages.
【０００７】また、上述の不合理を低減するには超電導
限流素子のクエンチ抵抗値を大きくする方法が考えられ
るが、この場合、超電導限流素子を構成する超電導体の
長さをクエンチ抵抗値に比例して長くする必要が生じ
る。超電導体の長さが長くなることは定常電流による導
体損失が増大することを意味し、超電導限流素子を冷却
する冷凍機サイズが大きくなり、維持電力も増大するな
どの不合理を生じる。In order to reduce the above irrationality, a method of increasing the quench resistance of the superconducting current limiting element is considered. In this case, the length of the superconductor constituting the superconducting current limiting element is determined by the quench resistance value. Needs to be lengthened in proportion to. An increase in the length of the superconductor means an increase in conductor loss due to a steady current, which causes an irrationality such as an increase in the size of a refrigerator for cooling the superconducting current limiting element and an increase in maintenance power.
【０００８】本発明は、上記事情に鑑みてなされたもの
で、低損失化及びコンパクト化を図ることのできる超電
導限流器を提供することを目的とする。The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a superconducting fault current limiter capable of achieving low loss and compactness.
【０００９】[0009]
【課題を解決するための手段】上記課題を解決するため
に、請求項１記載の発明は、所定の臨界電流値でクエン
チする第１の超電導限流素子と他の所定の臨界電流値で
クエンチする第２の超電導限流素子とを直列に接続して
限流器本体を構成し、前記第１の超電導限流素子のクエ
ンチに応じて開極動作する高速スイッチの主接点を前記
第２の超電導限流素子に並列に接続してなることを要旨
とする。この構成により、定常時には、第１、第２の超
電導限流素子は何れも超電導状態にあり、高速スイッチ
の主接点はオン状態にあることから、回路電流の殆どは
第１の超電導限流素子から高速スイッチの主接点側を流
れ、第２の超電導限流素子には僅かな電流しか流れな
い。その結果、定常時損失は第１の超電導限流素子を構
成する超電導体による交流損失のみとなり、僅かな値に
抑えられる。負荷に短絡事故等が生じて事故電流が流
れ、その事故電流が第１の超電導限流素子の臨界電流値
に達すると、第１の超電導限流素子がクエンチして事故
電流が所定値に限流される。また、このクエンチに応じ
て高速スイッチの主接点がオフし、このオフ動作によ
り、事故電流は第２の超電導限流素子側に転流する。こ
の転流電流が第２の超電導限流素子の臨界電流値を超え
ると第２の超電導限流素子もクエンチして高抵抗体に変
化し、事故電流はさらに低い値に限流される。その結
果、第１、第２の超電導限流素子に生じる限流時損失
は、第１の超電導限流素子のみで限流した場合と比較し
て非常に小さな値に抑えられる。そして、定常時損失の
抑制により超電導限流素子冷却用の冷凍機サイズとその
維持電力を最低限に抑えることが可能になると同時に、
限流時損失が非常に小さな値に抑えられることから冷媒
の気化量も非常に小さな値となり、クライオスタットの
耐圧力設計が簡易なもので済み、低コスト化が可能とな
る。In order to solve the above-mentioned problems, the invention according to claim 1 is the first superconducting current limiting element that quenches at a predetermined critical current value and the quench at another predetermined critical current value. A second superconducting current limiting element is connected in series to form a current limiting device main body, and a main contact of a high-speed switch that opens in response to a quench of the first superconducting current limiting element is connected to the second superconducting current limiting element. The gist is that it is connected in parallel with a superconducting current limiting element. With this configuration, in a steady state, the first and second superconducting current limiting devices are both in the superconducting state, and the main contact of the high-speed switch is in the on state, so most of the circuit current is in the first superconducting current limiting device. To the main contact side of the high-speed switch, and only a small current flows to the second superconducting current limiting element. As a result, the steady-state loss is only an AC loss due to the superconductor that constitutes the first superconducting current limiting element, and can be suppressed to a small value. When a short circuit accident occurs in the load and a fault current flows, and the fault current reaches the critical current value of the first superconducting current limiting element, the first superconducting current limiting element is quenched and the fault current is limited to a predetermined value. Shed In addition, the main contact of the high-speed switch is turned off in response to this quench, and this off operation causes the fault current to commutate to the second superconducting current limiting element side. When this commutation current exceeds the critical current value of the second superconducting current limiting element, the second superconducting current limiting element also quenches and changes to a high resistance, and the fault current is limited to a lower value. As a result, the current limiting loss occurring in the first and second superconducting current limiting devices is suppressed to a very small value as compared with the case where the current is limited only by the first superconducting current limiting device. Then, by suppressing the steady-state loss, it becomes possible to minimize the size of the refrigerator for cooling the superconducting current limiting element and its maintenance power, and at the same time,
Since the loss during current limiting is suppressed to a very small value, the vaporization amount of the refrigerant also becomes a very small value, and the pressure resistant design of the cryostat can be simplified and the cost can be reduced.
【００１０】請求項２記載の発明は、上記請求項１記載
の超電導限流器において、前記第２の超電導限流素子に
並列に、所定の時定数をもつＣＲフィルタ又はＣＲフィ
ルタとコンデンサの並列回路の何れかを接続してなるこ
とを要旨とする。この構成により、第１の超電導限流素
子のクエンチによる高速スイッチの主接点オフ後の第２
の超電導限流素子及びＣＲフィルタ等側への事故電流の
転流時間が大幅に短縮される。そして転流時間が短くな
ればなるほど、第２の超電導限流素子の高抵抗体への立
ち上がりが速まり、限流時における実効抵抗値が高くな
って限流時損失を一層低減することが可能となる。According to a second aspect of the present invention, in the superconducting fault current limiter according to the first aspect, a CR filter having a predetermined time constant or a CR filter and a capacitor in parallel are provided in parallel with the second superconducting fault current limiter. The gist is that any one of the circuits is connected. With this configuration, the second contact after turning off the main contact of the high-speed switch due to the quench of the first superconducting current limiting element
The commutation time of the fault current to the superconducting current limiting element and the CR filter side is significantly shortened. The shorter the commutation time, the faster the rising of the second superconducting current limiting element to the high resistance body, the higher the effective resistance value during current limiting, and the further the loss during current limiting can be further reduced. Becomes
【００１１】請求項３記載の発明は、上記請求項１又は
２記載の超電導限流器において、前記第２の超電導限流
素子に代えて、ＰＴＣ抵抗体を用いてなることを要旨と
する。この構成により、ＰＴＣ抵抗体は、常温下では非
常に低い抵抗率を保持し、通電電流によって自己発熱し
温度が上昇するに伴いその抵抗率が急激に上昇する。し
たがって事故電流発生時に高速スイッチの主接点のオフ
と同時に事故電流がＰＴＣ抵抗体を流れることから自己
発熱して急激に抵抗値が上昇し第２の超電導限流素子の
場合と同様に２段目の限流作用が行われて限流時損失の
低減化が図られる。そして、ＰＴＣ抵抗体は極低温に冷
却する必要のないことから冷凍機等のサイズを一層小型
化することが可能となる。A third aspect of the present invention is characterized in that, in the superconducting fault current limiter according to the first or second aspect, a PTC resistor is used instead of the second superconducting fault current limiter. With this configuration, the PTC resistor maintains a very low resistivity at room temperature, and its resistivity rapidly rises as the temperature rises due to self-heating due to the applied current. Therefore, when a fault current occurs, the fault current flows through the PTC resistor at the same time that the main contact of the high-speed switch is turned off, so that self-heating occurs and the resistance value suddenly rises, and the second stage is similar to the case of the second superconducting current limiting element. The current limiting action is performed to reduce the loss during current limiting. Since the PTC resistor does not need to be cooled to an extremely low temperature, it is possible to further reduce the size of the refrigerator or the like.
【００１２】請求項４記載の発明は、所定の臨界電流値
でクエンチする第１の超電導限流素子と所定の時定数を
もつＣＲフィルタ又はＣＲフィルタとコンデンサの並列
回路の何れかとを直列に接続して限流器本体を構成し、
前記第１の超電導限流素子のクエンチに応じて開極動作
する高速スイッチの主接点を前記所定の時定数をもつＣ
Ｒフィルタ又はＣＲフィルタとコンデンサの並列回路の
何れかに並列に接続してなることを要旨とする。この構
成により、請求項１記載の超電導限流器から第２の超電
導限流素子を取り去った構成となるが、事故電流発生時
に高速スイッチの主接点のオフと同時に事故電流がＣＲ
フィルタ等側に転流し、ＣＲフィルタ等のインピーダン
スによって２段目の限流作用が行われて限流時損失の低
減化が図られる。第２の超電導限流素子が無い分だけ冷
凍機等のサイズを一層小型化することが可能となる。According to a fourth aspect of the present invention, the first superconducting current limiting element that quenches at a predetermined critical current value and either a CR filter having a predetermined time constant or a parallel circuit of a CR filter and a capacitor are connected in series. And configure the current limiter body,
The main contact of the high-speed switch that opens in response to the quench of the first superconducting current limiting element has a C having the predetermined time constant.
The gist is that it is connected in parallel to either a parallel circuit of an R filter or a CR filter and a capacitor. With this configuration, the second superconducting fault current limiter is removed from the superconducting fault current limiter according to claim 1, but when the fault current occurs, the fault current is CR when the main contact of the high speed switch is turned off.
The current is commutated to the filter side, and the impedance of the CR filter or the like causes the second stage current limiting action to reduce the loss during current limiting. Since the second superconducting current limiting element is not provided, the size of the refrigerator or the like can be further reduced.
【００１３】請求項５記載の発明は、上記請求項１，
２，３又は４記載の超電導限流器において、前記高速ス
イッチに副接点を設け、該副接点を前記限流器本体に直
列に接続してなることを要旨とする。この構成により、
事故電流の発生後、これを限流した後、事故が復旧する
までの間、超電導限流器に流れる電流がゼロとなって限
流時損失をさらに低減することが可能となる。[0013] The fifth aspect of the present invention is the first aspect of the present invention.
The gist of the superconducting fault current limiter described in 2, 3, or 4 is that a sub-contact is provided on the high-speed switch, and the sub-contact is connected in series to the fault current limiter main body. With this configuration,
After the occurrence of the fault current, the current flowing through the superconducting fault current limiter becomes zero until the fault is recovered after the fault current is limited and the fault can be further reduced.
【００１４】請求項６記載の発明は、上記請求項１，
２，３，４又は５記載の超電導限流器において、前記高
速スイッチのトリップコイルの電源として前記第１の超
電導限流素子のクエンチ時に生じる両端電圧を用いてな
ることを要旨とする。この構成により、トリップコイル
駆動用の別途の電源が不要となって一層のコンパクト化
が図られる。[0014] The invention of claim 6 provides the above-mentioned claim 1,
In the superconducting fault current limiter described in 2, 3, 4 or 5, the gist is that the voltage across both ends generated during the quenching of the first superconducting fault current limiting device is used as the power supply for the trip coil of the high speed switch. With this configuration, a separate power supply for driving the trip coil is not required, and the size can be further reduced.
【００１５】請求項７記載の発明は、上記請求項１，
２，３，４又は５記載の超電導限流器において、前記高
速スイッチのトリップコイルの電源として別置きのコン
デンサバンクを用いてなることを要旨とする。この構成
により、トリップコイルの確実な駆動が保証される。The invention according to claim 7 is the above-mentioned claim 1,
The gist of the superconducting fault current limiter described in 2, 3, 4 or 5 is that a separately provided capacitor bank is used as a power source for the trip coil of the high speed switch. This configuration ensures a reliable drive of the trip coil.
【００１６】請求項８記載の発明は、上記請求項６又は
７記載の超電導限流器において、前記高速スイッチのト
リップコイルへの電源線路に、前記第１の超電導限流素
子がクエンチすると同時にオン状態に転じるスイッチを
接続してなることを要旨とする。この構成により、トリ
ップコイルへの無用な通電がなくなって誤動作が防止さ
れるとともに無用な電力消費が抑えられる。According to an eighth aspect of the present invention, in the superconducting fault current limiter according to the sixth or seventh aspect, the power line to the trip coil of the high speed switch is turned on at the same time when the first superconducting fault current limit device is quenched. The point is to connect a switch that changes to the state. With this configuration, unnecessary power supply to the trip coil is eliminated, malfunction is prevented, and unnecessary power consumption is suppressed.
【００１７】[0017]
【発明の実施の形態】以下、本発明の実施の形態を図面
に基づいて説明する。Embodiments of the present invention will be described below with reference to the drawings.
【００１８】図１乃至図３は、本発明の第１の実施の形
態を示す図である。まず、図１を用いて、本実施の形態
の超電導限流器の構成とその適用回路例を説明する。同
図において、１は電源、２は遮断器、３は負荷、４は本
実施の形態の超電導限流器である。超電導限流器４は、
第１の超電導限流素子５、第２の超電導限流素子６、主
接点Ｓ1 及び副接点Ｓ2 を備えた高速スイッチ７、冷凍
機８及びクライオスタット９で構成されている。第１の
超電導限流素子５は、所定の臨界電流値（例えば、３０
００Ａ）を有する超電導体を用いて構成した超電導スイ
ッチとなっており、クエンチによって６Ωの抵抗体に瞬
時に相転移するように構成されている。また、第２の超
電導限流素子６は、所定の臨界電流値（例えば、５０
Ａ）を有する超電導体を用いて構成した超電導スイッチ
となっており、クエンチによって約４２Ωの抵抗体に瞬
時に相転移するように構成されている。超電導スイッチ
とは、臨界電流値以下の電流に対しては超電導状態を維
持し、それ以上の電流が流れるとクエンチして高抵抗体
に変化するように構成された素子である。第１、第２の
超電導限流素子５，６で構成された限流器本体は、クラ
イオスタット９に収納された冷凍機８によって超電導状
態となる温度まで冷却されている。1 to 3 are views showing a first embodiment of the present invention. First, the configuration of a superconducting fault current limiter according to the present embodiment and an example of its application circuit will be described with reference to FIG. In the figure, 1 is a power supply, 2 is a circuit breaker, 3 is a load, and 4 is a superconducting fault current limiter of the present embodiment. The superconducting fault current limiter 4
It is composed of a first superconducting current limiting element 5, a second superconducting current limiting element 6, a high speed switch 7 having a main contact S 1 and an auxiliary contact S 2 , a refrigerator 8 and a cryostat 9. The first superconducting current limiting element 5 has a predetermined critical current value (for example, 30
It is a superconducting switch configured by using a superconductor having 00A), and is configured to instantaneously make a phase transition to a 6Ω resistor by quenching. Further, the second superconducting current limiting element 6 has a predetermined critical current value (for example, 50
The superconducting switch is configured by using the superconductor having A), and is configured to instantaneously make a phase transition to a resistor of about 42Ω by quenching. The superconducting switch is an element configured to maintain a superconducting state with respect to a current equal to or lower than a critical current value, and to quench when a current higher than the critical current value flows into a high resistance body. The current limiter body composed of the first and second superconducting current limiting elements 5 and 6 is cooled by a refrigerator 8 housed in a cryostat 9 to a temperature at which it becomes a superconducting state.
【００１９】図２は、高速スイッチ７の構成例を示して
いる。同図において、７ａは真空バルブ、７ｂは固定電
極、７ｃは可動電極、７ｄは短絡環、７ｅは電磁反発コ
イル（トリップコイル）、７ｆは開路ばね、７ｇは投入
電磁石、７ｈはヨーク、７ｉはワイプばね、７ｊは絶縁
フランジである。高速スイッチ７は、投入電磁石７ｇへ
の通電によってオン動作し、電磁反発コイル７ｅへの通
電によって高速にオフ動作する。この高速スイッチ７の
動作をさらに説明する。高速スイッチ７をオン動作させ
る場合は、投入電磁石７ｇに所定の電流を供給する。投
入電磁石７ｇは電流の供給を受けて電磁力を生じさせ、
開路ばね７ｆの開路力に打ち勝ってヨーク７ｈをＡ方向
に吸引する。このヨーク７ｈの働きは、ワイプばね７ｉ
及び絶縁フランジ７ｊを介して可動電極７ｃを上方に駆
動させることから、可動電極７ｃはついには固定電極７
ｂに接触し、高速スイッチ７はオン状態となる。オン状
態における高速スイッチ７の抵抗値は、接点間の接触抵
抗と固定及び可動電極の導体抵抗の和となるが、本実施
の形態では１０μΩになっているものとする。次に、高
速スイッチ７をオフ動作させる場合は、電磁反発コイル
７ｅに所定の電流を供給すると同時に投入電磁石７ｇへ
の電流供給を遮断する。投入電磁石７ｇへの電流供給が
遮断され、電磁反発コイル７ｅに電流が通電されると電
磁反発コイル７ｅは短絡環７ｄを貫通する磁束線を発生
する。電磁反発コイル７ｅの発生磁束線が短絡環７ｄを
貫通すると、導電体である短絡環７ｄには遮蔽電流が誘
起され、磁束線と遮蔽電流の作用によって短絡環７ｄと
電磁反発コイル７ｅは互いに反発し合う。短絡環７ｄと
可動電極７ｃは一体に嵌合されていることから、その反
発力によって可動電極７ｃも下方に駆動されて高速スイ
ッチ７はオフ状態となる。これと並行して投入電磁石７
ｇの電流も遮断されることから、投入電磁石７ｇのヨー
ク７ｈに対する吸引力が失われ、開路ばね７ｆの開路力
が可動電極７ｃの開極動作を加速する。FIG. 2 shows an example of the structure of the high speed switch 7. In the figure, 7a is a vacuum valve, 7b is a fixed electrode, 7c is a movable electrode, 7d is a short circuit ring, 7e is an electromagnetic repulsion coil (trip coil), 7f is an open spring, 7g is a closing electromagnet, 7h is a yoke, and 7i is The wipe spring 7j is an insulating flange. The high-speed switch 7 is turned on by energizing the closing electromagnet 7g, and is turned off at high speed by energizing the electromagnetic repulsion coil 7e. The operation of the high speed switch 7 will be further described. When the high-speed switch 7 is turned on, a predetermined current is supplied to the closing electromagnet 7g. The closing electromagnet 7g receives an electric current to generate an electromagnetic force,
The yoke 7h is attracted in the A direction by overcoming the opening force of the opening spring 7f. The function of the yoke 7h is that the wipe spring 7i
Since the movable electrode 7c is driven upward via the insulating flange 7j, the movable electrode 7c finally becomes the fixed electrode 7c.
Upon contact with b, the high speed switch 7 is turned on. The resistance value of the high-speed switch 7 in the ON state is the sum of the contact resistance between the contacts and the conductor resistance of the fixed and movable electrodes, but in the present embodiment, it is assumed to be 10 μΩ. Next, when the high-speed switch 7 is turned off, a predetermined current is supplied to the electromagnetic repulsion coil 7e and, at the same time, the current supply to the closing electromagnet 7g is cut off. When the current supply to the closing electromagnet 7g is cut off and the electromagnetic repulsion coil 7e is energized, the electromagnetic repulsion coil 7e generates a magnetic flux line penetrating the short-circuit ring 7d. When the generated magnetic flux line of the electromagnetic repulsion coil 7e penetrates the short-circuit ring 7d, a shielding current is induced in the short-circuit ring 7d which is a conductor, and the action of the magnetic flux line and the shielding current causes the short-circuit ring 7d and the electromagnetic repulsion coil 7e to repel each other. To meet each other. Since the short-circuit ring 7d and the movable electrode 7c are integrally fitted, the repulsive force also drives the movable electrode 7c downward so that the high-speed switch 7 is turned off. In parallel with this, the input electromagnet 7
Since the current of g is also cut off, the attraction force of the closing electromagnet 7g against the yoke 7h is lost, and the opening force of the opening spring 7f accelerates the opening operation of the movable electrode 7c.
【００２０】次に、図３を用いて、本実施の形態の超電
導限流器の作用を説明する。図３（ａ）は回路の全電
流、同図（ｂ）は第１の超電導限流素子５の抵抗値変化
特性、同図（ｃ）は第２の超電導限流素子６の抵抗値変
化特性、同図（ｄ）は高速スイッチ７の動作状態を示し
ている。定常時に、図１の回路は、遮断器２及び高速ス
イッチ７は何れもオン状態にあり、また第１の超電導限
流素子５、第２の超電導限流素子６の両方とも超電導状
態となっていることから、電源１から負荷３に対して支
障なく電力が供給される。このとき、第２の超電導限流
素子６側に流れる電流値ｉ2 は、次式に示すようにな
る。Next, the operation of the superconducting fault current limiter of this embodiment will be described with reference to FIG. 3A is the total current of the circuit, FIG. 3B is the resistance change characteristic of the first superconducting current limiting element 5, and FIG. 3C is the resistance change characteristic of the second superconducting current limiting element 6. , (D) shows the operating state of the high-speed switch 7. In the steady state, in the circuit of FIG. 1, both the circuit breaker 2 and the high-speed switch 7 are in the ON state, and both the first superconducting current limiting element 5 and the second superconducting current limiting element 6 are in the superconducting state. Therefore, the power is supplied from the power source 1 to the load 3 without any trouble. At this time, the current value i 2 flowing on the second superconducting current limiting element 6 side is as shown in the following equation.
【００２１】[0021]
【数２】 ｉ2 ＝ｉ1 ・｛（Ｒｓ2 ／Ｚ2 ）／（１＋Ｒｓ2 ／Ｚ2 ）｝0.5 （Ａ） …（２） ｉ1 ：全電流（Ａ） Ｒｓ：高速スイッチ回路の抵抗値（Ω） Ｚ：第２の超電導限流素子のインピーダンス Ｚ＝｛（２πｆ・Ｌｅ2 ）2 ＋Ｒｅ2 ｝0.5 （Ω） ｆ：周波数（Ｈｚ） Ｌｅ2 ：第２の超電導限流素子のインダクタンス（Ｈ） Ｒｅ：第２の超電導限流素子の抵抗値（Ω） 仮に、回路定数を ｉ1 ＝１０００（Ａ） Ｒｓ＝１０（μΩ） Ｚ＝｛（２πｆ・Ｌｅ2 ）2 ＋Ｒｃ2 ｝0.5 ＝０．０１０１（Ω） ｆ＝５０（Ｈｚ） Ｌｅ2 ＝５（μＨ） Ｒｃ＝０．０１（Ω） とすれば、 ｉ2 ＝１（Ａ） となり、定常時に第２の超電導限流素子６を流れる電流
に対して第２の超電導限流素子６は超電導状態を維持
し、かつ第２の超電導限流素子６自体の発生損失も無視
し得るほど小さい。[Equation 2] i 2 = i 1 · {(Rs 2 / Z 2 ) / (1 + Rs 2 / Z 2 )} 0.5 (A) (2) i 1 : Total current (A) Rs: Resistance of high-speed switch circuit Value (Ω) Z: Impedance of the second superconducting current limiting element Z = {(2πf · Le 2 ) 2 + Re 2 } 0.5 (Ω) f: Frequency (Hz) Le 2 : Inductance of the second superconducting current limiting element (H) Re: Resistance value of the second superconducting current limiting element (Ω) If the circuit constant is i 1 = 1000 (A) Rs = 10 (μΩ) Z = {(2πf · Le 2 ) 2 + Rc 2 } 0.5 = 0.0101 (Ω) f = 50 (Hz) Le 2 = 5 (μH) If Rc = 0.01 (Ω), then i 2 = 1 (A), and the second superconducting current limiting element is in steady state. The second superconducting current limiting element 6 maintains the superconducting state with respect to the current flowing through the second superconducting current limiting element 6, and the generated loss of the second superconducting current limiting element 6 itself. Negligibly small.
【００２２】次に、負荷３に短絡事故が生じた場合の作
用を説明する。負荷３に短絡が発生すると、回路電流
は、図３（ａ）に示すように、そのピークに向かって上
昇する。短絡電流が第１の超電導限流素子５の臨界電流
値３０００Ａに達すると第１の超電導限流素子５はクエ
ンチして、図３（ｂ）に示すように、６Ωの抵抗体に変
化し、仮に電源電圧を３８１０Ｖとすると短絡電流を図
３（ａ）に示すように９００Ａピークのレベルまで限流
する。このとき、高速スイッチ７の電磁反発コイル７ｅ
には第１の超電導限流素子５が抵抗体に変化したことに
よる抵抗性の端子電圧Ｅ1 が印加される。電磁反発コイ
ル７ｅに電圧が印加されると電流値に応じた磁束線が短
絡環７ｄを貫通する。磁束線の貫通により短絡環７ｄに
は遮蔽電流が流れ、その電流と磁界とによって短絡環７
ｄと電磁反発コイル７ｅとの間に電磁反発が生じる。こ
の電磁反発力によって可動電極７ｃが開極し、開極と同
時に高速スイッチ７の接点間にはアークが発生してアー
ク電圧を生じる。アーク電圧の発生により、回路電流は
並列に接続されている第２の超電導限流素子６側へ転流
する。この時の転流時間Ｔｃは高速スイッチ７と並列に
構成された第２の超電導限流素子６の回路時定数Ｌ／Ｒ
によって決定され、次式のようになる。Next, the operation when a short circuit accident occurs in the load 3 will be described. When a short circuit occurs in the load 3, the circuit current rises toward its peak, as shown in FIG. When the short-circuit current reaches the critical current value 3000A of the first superconducting current limiting element 5, the first superconducting current limiting element 5 is quenched and, as shown in FIG. 3 (b), changes to a 6Ω resistor, If the power supply voltage is 3810 V, the short-circuit current will be limited to the level of 900 A peak as shown in FIG. At this time, the electromagnetic repulsion coil 7e of the high-speed switch 7
Is applied with a terminal voltage E 1 which is resistive due to the change of the first superconducting current limiting element 5 into a resistor. When a voltage is applied to the electromagnetic repulsion coil 7e, the magnetic flux line corresponding to the current value penetrates the short circuit ring 7d. A shield current flows through the short-circuit ring 7d due to the penetration of the magnetic flux lines, and the short-circuit ring 7d is generated by the current and the magnetic field.
Electromagnetic repulsion occurs between d and the electromagnetic repulsion coil 7e. The movable electrode 7c is opened by this electromagnetic repulsive force, and at the same time as the opening, an arc is generated between the contacts of the high speed switch 7 to generate an arc voltage. Due to the generation of the arc voltage, the circuit current is commutated to the second superconducting current limiting element 6 side connected in parallel. The commutation time Tc at this time is the circuit time constant L / R of the second superconducting current limiting element 6 which is configured in parallel with the high speed switch 7.
Is determined by the following equation.
【００２３】[0023]
【数３】 Ｔｃ＝Ｌ2 ／Ｒ2 （ｓｅｃ） …（３） Ｌ2 ：第２の超電導限流素子回路のインダクタンス
（Ｈ） Ｒ2 ：第２の超電導限流素子回路の抵抗（Ω） 本実施の形態では、Ｌ2 ＝５μＨ，Ｒ2 ＝０．０１Ωで
あり、転流時間Ｔｃはおよそ５００μｓｅｃとなってい
る。即ち、高速スイッチが開極し始めてから５００μｓ
ｅｃ後にスイッチ電流がほぼゼロとなり、接点間アーク
が消滅して、高速スイッチ７の接点間は完全絶縁状態に
なる。一方、第２の超電導限流素子６を流れる電流は、
転流開始直後に第２の超電導限流素子６の臨界電流値を
超えるため、これにより第２の超電導限流素子６はクエ
ンチする。しかし、このとき第２の超電導限流素子６が
瞬時に抵抗を生じることはない。その理由は、超電導体
のクエンチ過程にフラックスフロー状態が存在すること
による。フラックスフロー状態とは、超電導体が超電導
状態から常電導状態に変化する際の中間状態を言い、そ
の抵抗率は常電導状態よりも数桁低く、継続時間は超電
導体の特性と冷媒による冷却特性によって決定される。
本超電導限流器では、フラックスフロー時間が５００μ
ｓｅｃ以上となるように設計されており、これにより高
速スイッチ７からの転流電流は完全に第２の超電導限流
素子６側へ転流した後、第２の超電導限流素子６の常電
導化によって図３（ａ）に示すように２段目の限流が行
われる。第２の超電導限流素子６のクエンチ抵抗値は４
２Ωとなっていることから、図１の回路には第１の超電
導限流素子５の限流抵抗値６Ωを加え４８Ωの限流抵抗
が挿入されることになる。Equation 3] Tc = L 2 / R 2 ( sec) ... (3) L 2: the second superconducting current limiting element circuit inductance (H) R 2: the resistance of the second superconducting current limiting element circuit (Omega) In this embodiment, L 2 = 5 μH, R 2 = 0.01 Ω, and the commutation time Tc is about 500 μsec. That is, 500 μs after the high speed switch starts to open
After ec, the switch current becomes almost zero, the arc between the contacts disappears, and the contacts of the high-speed switch 7 are completely insulated. On the other hand, the current flowing through the second superconducting current limiting element 6 is
Immediately after the start of commutation, the critical current value of the second superconducting current limiting element 6 is exceeded, so that the second superconducting current limiting element 6 is quenched. However, at this time, the second superconducting current limiting element 6 does not instantly generate resistance. The reason is that there is a flux flow state in the quenching process of the superconductor. The flux flow state is an intermediate state when the superconductor changes from the superconducting state to the normal conducting state, its resistivity is several orders of magnitude lower than that of the normal conducting state, and the duration is the characteristics of the superconductor and the cooling characteristics of the refrigerant. Determined by
With this superconducting fault current limiter, the flux flow time is 500μ.
It is designed so as to be longer than or equal to sec, whereby the commutation current from the high speed switch 7 is completely commutated to the second superconducting current limiting element 6 side, and then the normal conducting state of the second superconducting current limiting element 6 is reached. As a result, the second stage current limiting is performed as shown in FIG. The quench resistance value of the second superconducting current limiting element 6 is 4
Since it is 2Ω, the current limiting resistance value of 6Ω is added to the first superconducting current limiting element 5 in the circuit of FIG.
【００２４】上述したように、第１の実施の形態によれ
ば、常時は第１の超電導限流素子５のみに定常電流が流
れ、第２の超電導限流素子６には殆ど電流が流れないた
め、超電導限流素子の発生損失は第１の超電導限流素子
５のみとなり、定常電流通電による損失を抑制すること
がきる。事故電流に対しては、まず第１の超電導限流素
子５が第１波を限流した後、第２の超電導限流素子６に
よって２段目の限流を行う。これにより、限流抵抗値が
第１の超電導限流素子５のみの場合と比較して約８倍と
なり、限流損失を従来の１／８程度まで低減することが
できる。以上の効果をまとめると、定常時損失の抑制に
より冷凍機サイズと消費電力を最低限に抑えることがで
きると同時に、限流時損失を従来の１／８まで低減でき
るので冷媒の気化量も１／８となり、クライオスタット
の耐圧力設計が簡易なもので済み、低コスト化が可能と
なる。As described above, according to the first embodiment, a steady current always flows only in the first superconducting current limiting element 5 and almost no current flows in the second superconducting current limiting element 6. Therefore, the generated loss of the superconducting current limiting element is limited to the first superconducting current limiting element 5, and the loss due to the passing of the steady current can be suppressed. With respect to the fault current, first, the first superconducting current limiting element 5 limits the first wave, and then the second superconducting current limiting element 6 performs the second current limiting. As a result, the current limiting resistance value is about eight times that of the case of only the first superconducting current limiting element 5, and the current limiting loss can be reduced to about 1/8 of the conventional value. Summarizing the above effects, the refrigerator size and power consumption can be minimized by suppressing the steady-state loss, and at the same time, the current-limiting loss can be reduced to 1/8 of the conventional one, so that the refrigerant vaporization amount is also 1 Since the pressure resistance of the cryostat is simply designed, the cost can be reduced.
【００２５】図４及び図５には、本発明の第２の実施の
形態を示す。本実施の形態では、図４に示すように、第
２の超電導限流素子６に並列にコンデンサ１０ａと抵抗
１０ｂからなるＣＲフィルタ１０が接続されている。Ｃ
Ｒフィルタ１０を付加したことにより、さらに次のよう
な有効な作用、効果を奏する。これを図５を用いて説明
する。同図（ａ）はＣＲフィルタ１０がない場合の転流
特性を示し、同図（ｂ）はＣＲフィルタ１０を付加した
場合の転流特性を示している。図５（ａ），（ｂ）から
分かるように、ＣＲフィルタ１０の付加により高速スイ
ッチ７開極後の転流時間が大幅に短縮される。これは、
高速スイッチ７開極と同時に回路電流がＣＲフィルタ１
０側及び第２の超電導限流素子６側へ転流するためで、
転流の初期特性はＣＲフィルタ１０の時定数Ｔｃ＝Ｃ・
Ｒを任意に選定することで様々に調整できる。例えば、
コンデンサ１０ａのキャパシタンスを１０μＦ、抵抗１
０ｂの抵抗値を１０Ωに設定すれば、約１００μｓｅｃ
で高速スイッチ７から並列インピーダンス側へ転流が完
了する。転流時間が短くなればなるほど、第２の超電導
限流素子６の立ち上がりも速まり、限流時における実効
抵抗値が高くなって発生損失を低減できることになる。
ＣＲフィルタ１０の付加によるもう一つの効果として
は、第２の超電導限流素子６が常電導化して抵抗値が上
昇する際に発生する過渡回復電圧に対し、そのピークを
抑制するサージサプレッサとしても機能することであ
る。過渡回復電圧が抑制されれば、高速スイッチ７の再
発弧確率が低くなり信頼性が高まる。本実施の形態で
は、ＣＲフィルタ１０を例として示したが、これにコン
デンサを並列に接続すれば転流時間がさらに速まるとと
もにインピーダンスの発生を遅らせる効果を奏する。4 and 5 show a second embodiment of the present invention. In the present embodiment, as shown in FIG. 4, a CR filter 10 including a capacitor 10a and a resistor 10b is connected in parallel to the second superconducting current limiting element 6. C
By adding the R filter 10, the following effective actions and effects are further exhibited. This will be described with reference to FIG. The figure (a) shows the commutation characteristic when the CR filter 10 is not provided, and the figure (b) shows the commutation characteristic when the CR filter 10 is added. As can be seen from FIGS. 5 (a) and 5 (b), the addition of the CR filter 10 significantly reduces the commutation time after the opening of the high-speed switch 7. this is,
When the high-speed switch 7 is opened, the circuit current is CR filter 1 at the same time.
Because of commutation to the 0 side and the second superconducting current limiting element 6 side,
The initial characteristic of commutation is the time constant Tc = C · C of the CR filter 10.
Various adjustments can be made by arbitrarily selecting R. For example,
The capacitance of the capacitor 10a is 10 μF, the resistance 1
If the resistance value of 0b is set to 10Ω, about 100 μsec
Then, the commutation from the high speed switch 7 to the parallel impedance side is completed. The shorter the commutation time, the faster the rise of the second superconducting current limiting element 6, the higher the effective resistance value during current limiting, and the more the generated loss can be reduced.
Another effect of the addition of the CR filter 10 is also as a surge suppressor that suppresses the peak of the transient recovery voltage generated when the second superconducting current limiting element 6 becomes normal conducting and its resistance value rises. Is to work. If the transient recovery voltage is suppressed, the re-ignition probability of the high-speed switch 7 is reduced, and the reliability is increased. In the present embodiment, the CR filter 10 is shown as an example, but if a capacitor is connected in parallel with this, the commutation time is further shortened and the generation of impedance is delayed.
【００２６】図６には、本発明の第３の実施の形態を示
す。本実施の形態は、上記第２の実施の形態から第２の
超電導限流素子６を取り去った構成となっている。作用
としては、高速スイッチ７開極と同時にスイッチ電流が
ＣＲフィルタ１０側へ転流し、直後に高速スイッチ７の
極間が絶縁状態となりＣＲフィルタ１０のインピーダン
スによって２段目の限流が行われる。前述のＣＲフィル
タ１０の定数を用いれば、ＣＲフィルタ１０の５０Ｈｚ
交流に対するインピーダンスは次式に示すとおり３１
８．５Ωとなり、第２の実施の形態よりさらに第１の超
電導限流素子５で消費する限流時損失を低減することが
可能となる。FIG. 6 shows a third embodiment of the present invention. The present embodiment has a configuration in which the second superconducting current limiting element 6 is removed from the second embodiment. As a function, the switch current is commutated to the CR filter 10 side at the same time when the high-speed switch 7 is opened, and immediately after that, the poles of the high-speed switch 7 are in an insulated state, and the impedance of the CR filter 10 limits the second stage current. If the constant of the CR filter 10 is used, the CR filter 50 has a frequency of 50 Hz.
The impedance for alternating current is 31 as shown in the following equation.
It becomes 8.5Ω, and it is possible to further reduce the current-limiting loss consumed in the first superconducting current limiting element 5 as compared with the second embodiment.
【００２７】 Ｚ＝｛（１／ωＣ）2 ＋Ｒ2 ｝0.5 ＝３１８．５ （Ω） ω＝２πｆ ｆ＝５０Ｈｚ Ｃ＝１０μＦ Ｒ＝１０Ω 本実施の形態では、ＣＲフィルタ１０を例として示した
が、これにコンデンサを並列に接続すれば転流時間がさ
らに速まるとともにインピーダンスの発生を遅らせる効
果を奏する。Z = {(1 / ωC) 2 + R 2 } 0.5 = 318.5 (Ω) ω = 2πf f = 50 Hz C = 10 μF R = 10Ω In this embodiment, the CR filter 10 is shown as an example. By connecting a capacitor to this in parallel, the commutation time is further shortened and the generation of impedance is delayed.
【００２８】第４の実施の形態として、第２の超電導限
流素子に超電導体ではなく正の抵抗温度係数を有するＰ
ＴＣ（Positive Temperature Coefficient thermister
）抵抗体を用いることもできる。ＰＴＣ抵抗体を用い
ても、前記各実施の形態と同様の作用、効果を奏する。
ＰＴＣ抵抗体は、常温下では非常に低い抵抗率を保持す
るが、通電電流によって自己発熱し温度が上昇するに伴
いその抵抗率が急激に上昇する素子である。酸化バナジ
ウムを例にとれば、２０℃における抵抗率は１０-5Ω・
ｍであるが、１００℃まで温度上昇するとその抵抗率は
１０-2Ω・ｍまで急激に上昇する。即ち、定常時は第２
の超電導限流素子には殆ど電流が流れないため低抵抗を
維持し、事故電流発生時には高速スイッチの開極と同時
に事故電流が第２の超電導限流素子を流れることから自
己発熱して急激に抵抗値が上昇し２段目の限流作用を行
う。本実施の形態の利点は、第２の超電導限流素子を極
低温に冷却する必要のないことであるが、反面、超電導
限流素子による方式と比較すると熱的動作のために限流
応答速度が鈍くなる難点がある。As a fourth embodiment, the second superconducting current limiting element is not a superconductor but a P having a positive temperature coefficient of resistance.
TC (Positive Temperature Coefficient thermister
) A resistor can also be used. Even if the PTC resistor is used, the same operation and effect as those of the above-described respective embodiments can be obtained.
The PTC resistor is an element that retains a very low resistivity at room temperature, but its resistivity rapidly increases as the temperature rises due to self-heating due to the applied current. Taking vanadium oxide as an example, the resistivity at 20 ° C is 10 -5 Ω.
However, when the temperature rises to 100 ° C., the resistivity sharply rises to 10 −2 Ω · m. That is, in the steady state, the second
Since almost no current flows through the superconducting current limiting element of, low resistance is maintained, and when a fault current occurs, the fault current flows through the second superconducting current limiting element at the same time as the opening of the high speed switch. The resistance value rises and the second stage current limiting action is performed. The advantage of the present embodiment is that it is not necessary to cool the second superconducting current limiting element to a cryogenic temperature, but on the other hand, compared with the method using the superconducting current limiting element, the current limiting response speed is higher due to thermal operation. Has the drawback of becoming dull.
【００２９】図７には、本発明の第５の実施の形態を示
す。本実施の形態は、高速スイッチ７におけるトリップ
コイル７ｅの駆動回路に半導体スイッチ１１を付加し、
定常時にはこの半導体スイッチ１１をオフ状態にし、事
故発生時には第１の超電導限流素子５がクエンチすると
同時に半導体スイッチ１１をオン状態に制御するように
したものである。これにより、高速スイッチ７に配設さ
れたトリップコイル７ｅへの無用な通電をなくすことが
可能となる。FIG. 7 shows a fifth embodiment of the present invention. In the present embodiment, the semiconductor switch 11 is added to the drive circuit of the trip coil 7e in the high speed switch 7,
In the steady state, the semiconductor switch 11 is turned off, and when an accident occurs, the first superconducting current limiting device 5 is quenched and at the same time the semiconductor switch 11 is controlled to be turned on. This makes it possible to eliminate unnecessary energization of the trip coil 7e arranged in the high speed switch 7.
【００３０】以上、各実施の形態として、２つの超電導
限流素子と高速スイッチ及びＣＲフィルタを組み合わせ
た２段限流方式の基本構成と作用について説明してきた
が、各実施の形態の構成を任意数組み合わせた多段限流
方式も各実施の形態の延長として可能である。また、高
速スイッチにおけるトリップコイル電源としては別置き
のコンデンサバンク等を用いることもできる。Although the basic configuration and operation of the two-stage current limiting system in which two superconducting current limiting devices are combined with a high-speed switch and a CR filter have been described above as the respective embodiments, the configurations of the respective embodiments are arbitrary. A multi-stage current limiting method in which several combinations are used is also possible as an extension of each embodiment. Also, a separately placed capacitor bank or the like can be used as the trip coil power source in the high-speed switch.
【００３１】[0031]
【発明の効果】以上説明したように、請求項１記載の発
明によれば、所定の臨界電流値でクエンチする第１の超
電導限流素子と他の所定の臨界電流値でクエンチする第
２の超電導限流素子とを直列に接続して限流器本体を構
成し、前記第１の超電導限流素子のクエンチに応じて開
極動作する高速スイッチの主接点を前記第２の超電導限
流素子に並列に接続したため、定常時には、第１、第２
の超電導限流素子は何れも超電導状態にあり、高速スイ
ッチの主接点はオン状態にあることから、回路電流の殆
どは第１の超電導限流素子から高速スイッチの主接点側
を流れ、第２の超電導限流素子には僅かな電流しか流れ
ない。その結果、定常時損失は第１の超電導限流素子を
構成する超電導体による交流損失のみとなって僅かな値
に抑えることができる。負荷に短絡事故等が生じて事故
電流が流れ、その事故電流が第１の超電導限流素子の臨
界電流値に達すると、第１の超電導限流素子がクエンチ
して事故電流が所定値に限流される。また、このクエン
チに応じて高速スイッチの主接点がオフし、このオフ動
作により、事故電流は第２の超電導限流素子側に転流す
る。この転流電流が第２の超電導限流素子の臨界電流値
を超えると第２の超電導限流素子もクエンチして高抵抗
体に変化し、事故電流はさらに低い値に限流される。そ
の結果、第１、第２の超電導限流素子に生じる限流時損
失は、第１の超電導限流素子のみで限流した場合と比較
して非常に小さな値に抑えることができる。そして、定
常時損失の抑制により超電導限流素子冷却用の冷凍機サ
イズとその維持電力を最低限に抑えることができ、これ
と同時に、限流時損失が非常に小さな値に抑えられるこ
とから冷媒の気化量も非常に小さな値となり、クライオ
スタットの耐圧力設計を簡易なものとすることができ
る。As described above, according to the invention described in claim 1, the first superconducting current limiting element that quenches at a predetermined critical current value and the second superconducting current limiting element that quenches at another predetermined critical current value. A superconducting current limiting element is connected in series to form a current limiting device main body, and a main contact of a high-speed switch that opens in response to a quench of the first superconducting current limiting element is connected to the second superconducting current limiting element. Since it is connected in parallel to the
Since all of the superconducting current limiting devices are in the superconducting state and the main contact of the high speed switch is in the ON state, most of the circuit current flows from the first superconducting current limiting device to the main contact side of the high speed switch, Only a small amount of current flows through the superconducting current limiting device. As a result, the steady-state loss becomes only an AC loss due to the superconductor forming the first superconducting current limiting element and can be suppressed to a small value. When a short circuit accident occurs in the load and a fault current flows, and the fault current reaches the critical current value of the first superconducting current limiting element, the first superconducting current limiting element is quenched and the fault current is limited to a predetermined value. Shed In addition, the main contact of the high-speed switch is turned off in response to this quench, and this off operation causes the fault current to commutate to the second superconducting current limiting element side. When this commutation current exceeds the critical current value of the second superconducting current limiting element, the second superconducting current limiting element also quenches and changes to a high resistance, and the fault current is limited to a lower value. As a result, the current limiting loss occurring in the first and second superconducting current limiting devices can be suppressed to a very small value as compared with the case where the current is limited only by the first superconducting current limiting device. And, by suppressing the steady-state loss, the refrigerator size for cooling the superconducting current limiting element and its maintenance power can be minimized, and at the same time, the current limiting loss can be suppressed to a very small value. The vaporization amount of is also very small, and the pressure resistant design of the cryostat can be simplified.
【００３２】請求項２記載の発明によれば、前記第２の
超電導限流素子に並列に、所定の時定数をもつＣＲフィ
ルタ又はＣＲフィルタとコンデンサの並列回路の何れか
を接続したため、第１の超電導限流素子のクエンチによ
る高速スイッチの主接点オフ後の第２の超電導限流素子
及びＣＲフィルタ等側への事故電流の転流時間を大幅に
短縮することができる。そして転流時間が短くなればな
るほど、第２の超電導限流素子の高抵抗体への立ち上が
りが速まり、限流時における実効抵抗値が高くなって限
流時損失を一層低減することができる。According to the second aspect of the invention, since either the CR filter having a predetermined time constant or the parallel circuit of the CR filter and the capacitor is connected in parallel to the second superconducting current limiting element, the first superconducting current limiting element is connected. It is possible to significantly reduce the commutation time of the fault current to the second superconducting current limiting element and the CR filter side after the main contact of the high-speed switch is turned off due to the quenching of the superconducting current limiting element. The shorter the commutation time, the faster the rising of the second superconducting current limiting element to the high resistance body, the higher the effective resistance value during current limiting, and the further the loss during current limiting can be further reduced. .
【００３３】請求項３記載の発明によれば、前記第２の
超電導限流素子に代えて、ＰＴＣ抵抗体を用いたため、
ＰＴＣ抵抗体は、常温下では非常に低い抵抗率を保持
し、通電電流によって自己発熱し温度が上昇するに伴い
その抵抗率が急激に上昇する。したがって事故電流発生
時に高速スイッチの主接点のオフと同時に事故電流がＰ
ＴＣ抵抗体を流れることから自己発熱して急激に抵抗値
が上昇し第２の超電導限流素子の場合と同様に２段目の
限流作用が行われて限流時損失の低減化を図ることがで
きる。そして、ＰＴＣ抵抗体は極低温に冷却する必要の
ないことから冷凍機等のサイズを一層小型化することが
できる。According to the invention of claim 3, since the PTC resistor is used in place of the second superconducting current limiting element,
The PTC resistor has a very low resistivity at room temperature, and its resistivity rapidly increases as the temperature rises due to self-heating due to the applied current. Therefore, when a fault current occurs, the fault current will be P
Since it flows through the TC resistor, it self-heats and its resistance value suddenly rises. As in the case of the second superconducting current limiting element, the second stage current limiting action is performed to reduce loss during current limiting. be able to. Since the PTC resistor does not need to be cooled to an extremely low temperature, the size of the refrigerator or the like can be further reduced.
【００３４】請求項４記載の発明によれば、所定の臨界
電流値でクエンチする第１の超電導限流素子と所定の時
定数をもつＣＲフィルタ又はＣＲフィルタとコンデンサ
の並列回路の何れかとを直列に接続して限流器本体を構
成し、前記第１の超電導限流素子のクエンチに応じて開
極動作する高速スイッチの主接点を前記所定の時定数を
もつＣＲフィルタ又はＣＲフィルタとコンデンサの並列
回路の何れかに並列に接続したため、事故電流発生時に
高速スイッチの主接点のオフと同時に事故電流がＣＲフ
ィルタ等側に転流し、ＣＲフィルタ等のインピーダンス
によって２段目の限流作用が行われて限流時損失の低減
化を図ることができる。そして第２の超電導限流素子が
無い分だけ冷凍機等のサイズを一層小型化することがで
きる。According to the fourth aspect of the present invention, the first superconducting current limiting element that quenches at a predetermined critical current value and either a CR filter having a predetermined time constant or a parallel circuit of a CR filter and a capacitor are connected in series. The main contact of the high-speed switch, which constitutes the current limiter main body by being connected to the main superconducting current limiting element in response to the quench of the first superconducting current limiting element, is connected to the CR filter or the CR filter and the capacitor having the predetermined time constant Since they are connected in parallel to one of the parallel circuits, the fault current commutes to the CR filter side when the main contact of the high-speed switch turns off when a fault current occurs, and the impedance of the CR filter etc. causes the second stage current limiting action. Therefore, it is possible to reduce the loss during current limiting. Further, the size of the refrigerator or the like can be further reduced because the second superconducting current limiting element is not provided.
【００３５】請求項５記載の発明によれば、前記高速ス
イッチに副接点を設け、該副接点を前記限流器本体に直
列に接続したため、事故電流の発生後、これを限流した
後、事故が復旧するまでの間、超電導限流器に流れる電
流がゼロとなって限流時損失をさらに低減することがで
きる。According to the fifth aspect of the present invention, since the high speed switch is provided with a sub-contact and the sub-contact is connected in series with the current limiting device main body, after the fault current is generated and the current is limited, Until the accident is recovered, the current flowing through the superconducting fault current limiter becomes zero, and the current limiting loss can be further reduced.
【００３６】請求項６記載の発明によれば、前記高速ス
イッチのトリップコイルの電源として前記第１の超電導
限流素子のクエンチ時に生じる両端電圧を用いたため、
トリップコイル駆動用の別途の電源が不要となって一層
のコンパクト化を図ることができる。According to the sixth aspect of the present invention, since the voltage across both ends generated during the quench of the first superconducting current limiting element is used as the power supply for the trip coil of the high speed switch,
A separate power supply for driving the trip coil is not required, and further compactness can be achieved.
【００３７】請求項７記載の発明によれば、前記高速ス
イッチのトリップコイルの電源として別置きのコンデン
サバンクを用いたため、トリップコイルの確実な駆動が
保証される。According to the seventh aspect of the present invention, since the separately placed capacitor bank is used as the power source of the trip coil of the high-speed switch, reliable drive of the trip coil is guaranteed.
【００３８】請求項８記載の発明によれば、前記高速ス
イッチのトリップコイルへの電源線路に、前記第１の超
電導限流素子がクエンチすると同時にオン状態に転じる
スイッチを接続したため、トリップコイルへの無用な通
電がなくなって誤動作を防止することができるとともに
無用な電力消費を抑えることができる。According to the invention as set forth in claim 8, since the switch which turns on at the same time when the first superconducting current limiting device is quenched is connected to the power supply line to the trip coil of the high speed switch, the trip coil is connected to the trip coil. It is possible to prevent unnecessary operation by eliminating unnecessary energization and to suppress unnecessary power consumption.
【図１】本発明に係る超電導限流器の第１の実施の形態
を示す回路図である。FIG. 1 is a circuit diagram showing a first embodiment of a superconducting fault current limiter according to the present invention.
【図２】上記第１の実施の形態における高速スイッチの
構成例を示す図である。FIG. 2 is a diagram showing a configuration example of a high-speed switch according to the first embodiment.
【図３】上記第１の実施の形態の回路電流と超電導限流
素子抵抗値等の変化特性を示す図である。FIG. 3 is a diagram showing change characteristics of the circuit current and the superconducting current limiting element resistance value and the like in the first embodiment.
【図４】本発明の第２の実施の形態を示す回路図であ
る。FIG. 4 is a circuit diagram showing a second embodiment of the present invention.
【図５】上記第２の実施の形態におけるＣＲフィルタの
作用を説明するための図である。FIG. 5 is a diagram for explaining the operation of the CR filter in the second embodiment.
【図６】本発明の第３の実施の形態を示す回路図であ
る。FIG. 6 is a circuit diagram showing a third embodiment of the present invention.
【図７】本発明の第５の実施の形態を示す回路図であ
る。FIG. 7 is a circuit diagram showing a fifth embodiment of the present invention.
【図８】従来の超電導限流器を示す回路図である。FIG. 8 is a circuit diagram showing a conventional superconducting fault current limiter.
５ 第１の超電導限流素子 ６ 第２の超電導限流素子 ７ 高速スイッチ ７ｅ 電磁反発コイル（トリップコイル） ９ クライオスタット １０ ＣＲフィルタ １１ 半導体スイッチ 5 First Superconducting Current Limiting Element 6 Second Superconducting Current Limiting Element 7 High Speed Switch 7e Electromagnetic Repulsion Coil (Trip Coil) 9 Cryostat 10 CR Filter 11 Semiconductor Switch
───────────────────────────────────────────────────── フロントページの続き (72)発明者 大熊 武 神奈川県横浜市鶴見区江ケ崎町４番１号 東京電力株式会社電力技術研究所内 (72)発明者 ▲つる▼永 和行 東京都府中市東芝町１番地 株式会社東芝 府中工場内 (72)発明者 松崎 順 東京都府中市東芝町１番地 株式会社東芝 府中工場内 (72)発明者 横倉 邦夫 東京都府中市東芝町１番地 株式会社東芝 府中工場内 (72)発明者 矢澤 孝 神奈川県川崎市幸区小向東芝町１ 株式会 社東芝研究開発センター内 (72)発明者 野村 俊自 神奈川県川崎市幸区小向東芝町１ 株式会 社東芝研究開発センター内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takeshi Okuma 4-1, Egasaki-cho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Electric Power Technology Laboratory (72) Inventor ▲ Tsuru ▼ Kazuyuki Ei Toshiba, Fuchu-shi, Tokyo Town No. 1 in Toshiba Fuchu Plant (72) Inventor Jun Matsuzaki No. 1 in Toshiba Town Fuchu, Tokyo Fuchu Plant (72) Inventor Kunio Yokokura No. 1 in Toshiba Town Fuchu, Tokyo Toshiba Fuchu Plant Co., Ltd. (72) Inventor Takashi Yazawa 1 Komukai Toshiba Town Co., Ltd., Kobayashi-ku, Kawasaki-shi, Kanagawa Toshiba Research & Development Center (72) Inventor Toshiki Nomura 1 Komukai Toshiba Town, Kawasaki-shi, Kanagawa Toshiba Corporation R & D Center
Claims (8)
超電導限流素子と他の所定の臨界電流値でクエンチする
第２の超電導限流素子とを直列に接続して限流器本体を
構成し、前記第１の超電導限流素子のクエンチに応じて
開極動作する高速スイッチの主接点を前記第２の超電導
限流素子に並列に接続してなることを特徴とする超電導
限流器。1. A current limiting device main body comprising a first superconducting current limiting element quenching at a predetermined critical current value and a second superconducting current limiting element quenching at another predetermined critical current value connected in series. A superconducting fault current limiter, characterized in that the main contact of a high-speed switch that opens according to a quench of the first superconducting fault current limiting element is connected in parallel to the second superconducting fault current limiting element. .
定の時定数をもつＣＲフィルタ又はＣＲフィルタとコン
デンサの並列回路の何れかを接続してなることを特徴と
する請求項１記載の超電導限流器。2. A CR filter having a predetermined time constant or a parallel circuit of a CR filter and a capacitor is connected in parallel to the second superconducting current limiting element. Superconducting fault current limiter.
ＴＣ抵抗体を用いてなることを特徴とする請求項１又は
２記載の超電導限流器。3. The second superconducting current limiting element is replaced with P
The superconducting fault current limiter according to claim 1 or 2, wherein the TC resistor is used.
超電導限流素子と所定の時定数をもつＣＲフィルタ又は
ＣＲフィルタとコンデンサの並列回路の何れかとを直列
に接続して限流器本体を構成し、前記第１の超電導限流
素子のクエンチに応じて開極動作する高速スイッチの主
接点を前記所定の時定数をもつＣＲフィルタ又はＣＲフ
ィルタとコンデンサの並列回路の何れかに並列に接続し
てなることを特徴とする超電導限流器。4. A current limiting device main body by connecting in series a first superconducting current limiting element that quenches at a predetermined critical current value and either a CR filter having a predetermined time constant or a parallel circuit of a CR filter and a capacitor. And a main contact of a high-speed switch that opens according to a quench of the first superconducting current limiting element is connected in parallel to either a CR filter having the predetermined time constant or a parallel circuit of a CR filter and a capacitor. A superconducting fault current limiter characterized by being connected.
接点を前記限流器本体に直列に接続してなることを特徴
とする請求項１，２，３又は４記載の超電導限流器。5. The superconducting fault current limiter according to claim 1, wherein the high speed switch is provided with a sub-contact, and the sub-contact is connected in series with the main body of the fault current limiter. .
源として前記第１の超電導限流素子のクエンチ時に生じ
る両端電圧を用いてなることを特徴とする請求項１，
２，３，４又は５記載の超電導限流器。6. A power supply for a trip coil of the high speed switch, wherein a voltage across both ends generated when the first superconducting current limiting element is quenched is used.
The superconducting fault current limiter of 2, 3, 4 or 5.
源として別置きのコンデンサバンクを用いてなることを
特徴とする請求項１，２，３，４又は５記載の超電導限
流器。7. The superconducting fault current limiter according to claim 1, wherein a separate capacitor bank is used as a power source for the trip coil of the high-speed switch.
電源線路に、前記第１の超電導限流素子がクエンチする
と同時にオン状態に転じるスイッチを接続してなること
を特徴とする請求項６又は７記載の超電導限流器。8. The switch for turning on the switch at the same time when the first superconducting current limiting device is quenched is connected to the power supply line to the trip coil of the high-speed switch. Superconducting fault current limiter.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8032292A JPH09233692A (en) | 1996-02-20 | 1996-02-20 | Superconuctive current limiter |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP8032292A JPH09233692A (en) | 1996-02-20 | 1996-02-20 | Superconuctive current limiter |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH09233692A true JPH09233692A (en) | 1997-09-05 |
Family
ID=12354892
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP8032292A Pending JPH09233692A (en) | 1996-02-20 | 1996-02-20 | Superconuctive current limiter |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH09233692A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008283106A (en) * | 2007-05-14 | 2008-11-20 | National Institute Of Advanced Industrial & Technology | Superconductive current limiting element |
| JP2009049257A (en) * | 2007-08-22 | 2009-03-05 | National Institute Of Advanced Industrial & Technology | Superconducting current-limiting element |
| ES2320296A1 (en) * | 2005-12-02 | 2009-05-20 | Ls Industrial Systems Co., Ltd. | Electric power circuit protecting apparatus using superconductor |
| KR101981056B1 (en) * | 2018-11-14 | 2019-08-28 | 한국기초과학지원연구원 | superconductor magnet apparatus |
-
1996
- 1996-02-20 JP JP8032292A patent/JPH09233692A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| ES2320296A1 (en) * | 2005-12-02 | 2009-05-20 | Ls Industrial Systems Co., Ltd. | Electric power circuit protecting apparatus using superconductor |
| JP2008283106A (en) * | 2007-05-14 | 2008-11-20 | National Institute Of Advanced Industrial & Technology | Superconductive current limiting element |
| JP2009049257A (en) * | 2007-08-22 | 2009-03-05 | National Institute Of Advanced Industrial & Technology | Superconducting current-limiting element |
| KR101981056B1 (en) * | 2018-11-14 | 2019-08-28 | 한국기초과학지원연구원 | superconductor magnet apparatus |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US5414586A (en) | Superconducting current limiting device | |
| JPH0586052B2 (en) | ||
| KR100823848B1 (en) | Half-wave limitable superconducting fault-current limiters | |
| JPH09233692A (en) | Superconuctive current limiter | |
| JPH0576162B2 (en) | ||
| WO2014058871A1 (en) | Fast superconducting switch for superconducting power devices | |
| JP2007274744A (en) | Superconductive current limiting device, superconductive current limiting system and superconductive current limiting control method | |
| JP2000090788A (en) | Current limiting device and current limiting breaking device | |
| JPH1027721A (en) | Superconductive coil | |
| JPH06350148A (en) | Perpetual current superconducting device | |
| JP2947927B2 (en) | Superconducting current limiting device | |
| EP2973920B1 (en) | Superconducting fault current limiter system | |
| JPH04312717A (en) | Superconducting current limiter | |
| JP3231837B2 (en) | Superconducting current limiting device | |
| US20110007432A1 (en) | Power Node Switching Center With Active Feedback Control Of Power Switches | |
| Shimizu et al. | Operation of superconducting fault current limiter using vacuum interrupter driven by electromagnetic repulsion force for commutating switch | |
| JPH02260343A (en) | High voltage dc contact breaker circuit | |
| US20240155951A1 (en) | Superconducting magnet device, nmr device, and mri device | |
| JPH0787666A (en) | Current limiting device | |
| JP2004186524A (en) | Superconducting magnet device and superconducting transformer | |
| JP2018163930A (en) | Superconducting coil device and method for protecting the same | |
| JP4750925B2 (en) | Current limiter | |
| JP2853347B2 (en) | Current lead of superconducting magnet device | |
| JP2003109816A (en) | Protection circuit for superconducting magnet equipment | |
| JP2566947B2 (en) | Specified voltage conducting element for cryogenic temperature and superconducting magnet using this element |