JP3943817B2 - Vacuum DC circuit breaker - Google Patents

Description

【００７６】
また、小電流遮断時でスイッチ４２が開極したケースでは、放電回路のインピーダンスＺ₂は、下記の（２）式、スイッチ４２，４４共に開極したケースでは、放電回路のインピーダンスＺ₃は、下記の（３）式のようになる。
【００７７】
【数２】

となる。
【００７８】
コンデンサ４の充電電圧をＥとすると、放電電流の波高値Ｉ_pは、下記の（４）式で表わすことができる。
【００７９】
Ｉ_p＝Ｅ／Ｚ_N ……（４）
ここで、Ｎ＝１，２，３である。
【００８０】
この（４）式からわかるように、主真空バルブ１に流れている電流に応じて、スイッチ４２，４４を開極することにより、放電電流の波高値Ｉ_pが小さくなる。
【００８１】
次に、前記図１０に示した抵抗負荷の小電流遮断で、主真空バルブ１で電流遮断後に、副真空バルブ２に流れる電流を考える。
【００８２】
この時、副真空バルブ２に流れる電流は、抵抗負荷の抵抗値Ｒが大きく、非振動波形になるとする。
【００８３】
図１０に示す回路で、その電流の減衰時定数τ₁は、下記の（５）式のようになる。
【００８４】
τ₁＝Ｒ・Ｃ₄ ……（５）
本実施の形態による図１に示す真空直流遮断器を用いて、スイッチ４２，４４が閉極した状態の時定数は、上記と同じτ₁となる。
【００８５】
一方、スイッチ４２が開極した時の時定数τ₂、およびスイッチ４２，４４が共に開極した時の時定数τ₃は、それぞれ（６）式、（７）式のようになる。
【００８６】
【数３】

【００８７】
このことから、主真空バルブ１に流れる電流に応じて、スイッチ４２，４４を開極することにより、副真空バルブ２に流れる電流の時定数が短くなり、結果として副真空バルブ２で最終的に電流を遮断するまでの時間を短縮することができる。
【００８８】
上述したように、本実施の形態による真空直流遮断器では、小電流遮断時に副真空バルブ２の遮断点の遅延を抑制する、すなわち小電流遮断時に真空直流遮断器の遮断時間が遅延するのを防止することが可能となる。
【００８９】
（第２の実施の形態）
本実施の形態による真空直流遮断器は、前述した図１に示す第１の実施の形態の真空直流遮断器において、前記コンデンサ４３、およびスイッチ４４を省略して、２個のコンデンサ４，４１を直列に接続し、コンデンサ４１と並列にスイッチ４２を接続した構成としている。
【００９０】
すなわち、前記第１の実施の形態の真空直流遮断器において、複数のコンデンサとして、２個のコンデンサ４，４１を直列に接続した構成としている。
【００９１】
次に、以上のように構成した本実施の形態による真空直流遮断器においては、２個のコンデンサ４，４１を直列に接続していることにより、前記第１の実施の形態の真空直流遮断器の場合に比べて、前記コンデンサ４３、およびスイッチ４４を省略した分だけ、部品点数の減少を図ることができる。
【００９２】
上述したように、本実施の形態による真空直流遮断器では、前記第１の実施の形態と同様の効果が得られるのに加えて、部品点数の減少を図ることが可能となる。
【００９３】
（第３の実施の形態）
本実施の形態による真空直流遮断器は、前述した図１に示す第１の実施の形態の真空直流遮断器において、前記コンデンサ４１，４３と並列に接続されたスイッチ４２，４４として、サイリスタ（あるいはＧＴＯ，ＩＧＢＴ，ＩＥＧＴ）とダイオードとが互いに逆並列に接続された半導体スイッチとした構成としている。
【００９４】
次に、以上のように構成した本実施の形態による真空直流遮断器においては、コンデンサ４１，４３と並列に接続されたスイッチ４２，４４を、サイリスタ （あるいはGT0やIGBT,IEGT）とダイオードとが互いに逆並列に接続された半導体スイッチとしていることにより、スイッチ４２，４４を高速操作することができる。
【００９５】
上述したように、本実施の形態による真空直流遮断器では、前記第１の実施の形態と同様の効果が得られるのに加えて、スイッチ４２，４４を高速操作することが可能となる。
【００９６】
（第４の実施の形態）
図２は、本実施の形態による真空直流遮断器の構成例を示す回路図であり、図１と同一部分には同一符号を付してその説明を省略し、ここでは異なる部分についてのみ述べる。
【００９７】
すなわち、本実施の形態による真空直流遮断器は、図２に示すように、前記図１におけるコンデンサ４３、およびスイッチ４４を省略して、スイッチ４２が並列に接続されたコンデンサ４１と直列に、リアクトル５１（第２のリアクトル）を接続した構成としている。
【００９８】
次に、以上のように構成した本実施の形態による真空直流遮断器においては、スイッチ４１が並列に接続されたコンデンサ４１と直列に、リアクトル５１を挿入していることにより、合成電流の電流零点のｄＩ／ｄｔを小さくして、主真空バルブ１で確実に合成電流が消弧できるようにすることができる。
【００９９】
すなわち、コンデンサ４１の静電容量が小さくなると、主真空バルブ１に流れる高周波電流の周波数が大きくなり、合成電流の電流零点のｄＩ／ｄｔが大きくなり、主真空バルブ１が消弧し難くなる。
【０１００】
この点、本実施の形態では、これを防止するために、スイッチ４１が並列に接続されたコンデンサ４１と直列にリアクトル５１を挿入していることにより、合成電流の電流零点のｄＩ／ｄｔを小さくして、主真空バルブ１で確実に合成電流が消弧できるようにすることができる。
【０１０１】
上述したように、本実施の形態による真空直流遮断器では、前記第１の実施の形態と同様の効果が得られるのに加えて、主真空バルブ１で確実に合成電流が消弧できるようにすることが可能となる。
【０１０２】
（第５の実施の形態）
図３は、本実施の形態による真空直流遮断器の構成例を示す回路図であり、図１と同一部分には同一符号を付してその説明を省略し、ここでは異なる部分についてのみ述べる。
【０１０３】
すなわち、本実施の形態による真空直流遮断器は、図３に示すように、前記図１におけるコンデンサ４３、およびスイッチ４４を省略して、スイッチ４２が並列に接続されたコンデンサ４１を、リアクトル５１（第２のリアクトル）に置き換えた構成としている。
【０１０４】
次に、以上のように構成した本実施の形態による真空直流遮断器においては、スイッチ４２が並列に接続されたコンデンサ４１を、リアクトル５１に置き換えていることにより、主真空バルブ１の損傷を抑制できると共に、合成電流を確実に遮断できるようにすることができる。
【０１０５】
すなわち、小電流遮断時にスイッチ４２が開極した状態で、半導体スイッチ３がＯＮすると、コンデンサ４に蓄えられた電荷が放電して主真空バルブ１に流れる高周波電流の波高値Ｉ_Pは、リアクトル５１のインダクタンスをＬ₅₁とすると、下記の（８）式のようになる。
【０１０６】
【数４】

【０１０７】
このリアクトル５１のインダクタンスＬ₅₁が大きくなると、主真空バルブ１に流れる高周波電流の波高値Ｉ_Pが小さくなり、主真空バルブ１の損傷を抑制できると共に、合成電流を確実に遮断できるようになる。
【０１０８】
上述したように、本実施の形態による真空直流遮断器では、前記第１の実施の形態と同様の効果が得られるのに加えて、主真空バルブ１の損傷を抑制できると共に、合成電流を確実に遮断できるようにすることが可能となる。
【０１０９】
（第６の実施の形態）
図４は、本実施の形態による真空直流遮断器の構成例を示す回路図であり、図１と同一部分には同一符号を付してその説明を省略し、ここでは異なる部分についてのみ述べる。
【０１１０】
すなわち、本実施の形態による真空直流遮断器は、図４に示すように、前記図１におけるリアクトル５と、コンデンサ４３、およびスイッチ４４を省略して、スイッチ４２が並列に接続されたコンデンサ４１を、リアクトル５３（第３のリアクトル）に置き換え、さらにこのリアクトル５３が並列に接続されたスイッチ４２と直列に、リアクトル５４（第４のリアクトル）を接続した構成としている。
【０１１１】
次に、以上のように構成した本実施の形態による真空直流遮断器においては、リアクトル５４と直列にスイッチ４２を配し、この直列回路と並列にリアクトル５３を接続していることにより、小電流遮断時に、主真空バルブ１に流れる高周波電流と合成した電流のｄＩ／ｄｔを抑制することができる。
【０１１２】
すなわち、主真空バルブ１で大電流を遮断するケースでは、スイッチ４２を閉極し、リアクトル５３，５４が並列接続になり、小電流遮断時には、スイッチ４２を開極し、リアクトル５３にだけ電流が流れる。
【０１１３】
ここで、リアクトル５３のインダクタンスをＬ₅₃、リアクトル５４のインダクタンスをＬ₅₄とし、Ｌ₅₃＞Ｌ₅₄となるようにしておくことにより、小電流遮断時に主真空バルブ１に流れる高周波電流と合成した電流のｄＩ／ｄｔを抑制することができる。
【０１１４】
上述したように、本実施の形態による真空直流遮断器では、前記第１の実施の形態と同様の効果が得られるのに加えて、小電流遮断時に、一方の真空バルブに流れる高周波電流と合成した電流のｄＩ／ｄｔを抑制することが可能となる。
【０１１５】
（第７の実施の形態）
図５は、本実施の形態による真空直流遮断器の構成例を示す回路図であり、図１と同一部分には同一符号を付してその説明を省略し、ここでは異なる部分についてのみ述べる。
【０１１６】
すなわち、本実施の形態による真空直流遮断器は、図５に示すように、前記図１におけるスイッチ４２が並列に接続されたコンデンサ４１、およびスイッチ４４が並列に接続されたコンデンサ４３と並列に、抵抗６１および抵抗６２を接続した構成としている。
【０１１７】
次に、以上のように構成した本実施の形態による真空直流遮断器においては、スイッチ４２，４４が並列に接続されたコンデンサ４１，４３と並列に、抵抗６１，６２を接続していることにより、二つの真空バルブ１，２遮断後にコンデンサ４１，４３に残る残留電荷を抵抗６１，６２で放電した後に、スイッチ４２，４４を投入して、スイッチ４２，４４あるいはコンデンサ４１，４３に損傷を与えるのを無くすることができる。
【０１１８】
すなわち、主真空バルブ１、副真空バルブ２遮断後に、コンデンサ４１、コンデンサ４３に残留電荷が残る。
【０１１９】
そして、この状態でスイッチ４２，４４を閉じると、残留電荷がスイッチ４２，４４を介して放電し、スイッチ４２，４４あるいはコンデンサ４１，４３に損傷を与える。
【０１２０】
この点、本実施の形態では、これを無くするために、抵抗６１，６２で残留電荷を放電した後に、スイッチ４２，４４を投入することにより、スイッチ４２，４４あるいはコンデンサ４１，４３に損傷を与えるのを無くすることができる。
【０１２１】
上述したように、本実施の形態による真空直流遮断器では、前記第１の実施の形態と同様の効果が得られるのに加えて、スイッチ４２，４４あるいはコンデンサ４１，４３に損傷を与えるのを無くすることが可能となる。
【０１２２】
（第８の実施の形態）
図６は、本実施の形態による真空直流遮断器の構成例を示す回路図であり、図９と同一部分には同一符号を付してその説明を省略し、ここでは異なる部分についてのみ述べる。
【０１２３】
すなわち、本実施の形態による真空直流遮断器は、図６に示すように、前記図９における半導体スイッチ３の挿入位置を、電源側に配した構成としている。
【０１２４】
次に、以上のように構成した本実施の形態による真空直流遮断器においては、半導体スイッチ３の挿入位置を電源側としていることにより、半導体スイッチ３に加わる電圧を低減することができる。
【０１２５】
すなわち、前記図９に示す構成の回路で、電源電圧Ｖ_sとコンデンサ４の充電電圧Ｅとすると、半導体スイッチ３の対地電位Ｖ_swは、
Ｖ_sw＝Ｖ_s＋Ｅ
となる。
【０１２６】
これに対して、図６に示す本実施の形態のように、半導体スイッチ３を電源側に設置すると、
Ｖ_sw＝Ｖ_s
となり、半導体スイッチ３に加わる電圧を低減できる。
【０１２７】
上述したように、本実施の形態による真空直流遮断器では、半導体スイッチ３に加わる電圧を低減することが可能となる。
【０１２８】
（第９の実施の形態）
本実施の形態による真空直流遮断器は、前述した図９に示す従来の真空直流遮断器において、前記半導体スイッチ３のサイリスタを、ＧＴＯ、ＩＧＢＴ、ＩＥＧＴ等の自己消弧型素子とした、すなわち半導体スイッチ３として、自己消弧型素子を組込んだ半導体スイッチを用いた構成としている。
【０１２９】
次に、以上のように構成した本実施の形態による真空直流遮断器においては、半導体スイッチ３として、自己消弧型素子を組込んだ半導体スイッチを用いていることにより、非振動電流が副真空バルブ２で遮断できない領域であっても、自己消弧型素子で強制的に遮断することができる。
【０１３０】
すなわち、前記図１０に示す回路で示した抵抗負荷回路の電流遮断時には、副真空バルブ２を流れる電流が非振動になるケースがあり、この場合には副真空バルブ２で電流遮断される時間が遅延する。
【０１３１】
この点、本実施の形態では、これを問題を解決するために、自己消弧型素子を組込んだ半導体スイッチ３を用いることにより、非振動電流が副真空バルブ２で遮断できない領域であっても、自己消弧型素子で強制的に遮断することができる。
【０１３２】
上述したように、本実施の形態による真空直流遮断器では、非振動電流が副真空バルブ２で遮断できない領域であっても、自己消弧型素子で強制的に遮断することが可能となる。
【０１３３】
（第１０の実施の形態）
図７は、本実施の形態による真空直流遮断器の構成例を示す回路図であり、図９と同一部分には同一符号を付してその説明を省略し、ここでは異なる部分についてのみ述べる。
【０１３４】
すなわち、本実施の形態による真空直流遮断器は、図７に示すように、前記図９における主真空バルブ１と並列に、可飽和リアクトル７を接続した構成としている。
【０１３５】
次に、以上のように構成した本実施の形態による真空直流遮断器においては、主真空バルブ１と並列に可飽和リアクトル７を接続していることにより、抵抗負荷の小電流遮断時に、副真空バルブ２を流れる電流が非振動になる場合であっても、可飽和リアクトル７で電流零点を作り、この電流零点で副真空バルブ２が消弧して、遮断時間を短縮することができる。
【０１３６】
すなわち、前記図１０に示す回路で示した抵抗負荷回路の小電流遮断時には、副真空バルブ２を流れる電流が非振動になるケースがあり、この場合には副真空バルブ２で電流遮断される時間が遅延する。
【０１３７】
この時、主真空バルブ１の極間電圧は、ほぼコンデンサ４と同じ電圧であり、直流の減衰波形になる。
【０１３８】
そして、この直流減衰波形が可飽和リアクトル７に加わると、可飽和リアクトル７が飽和し、コンデンサ４の電荷が可飽和リアクトル７を流れて、コンデンサ４の電圧の極性が反転する。
【０１３９】
このコンデンサ４の電圧が反転すると、副真空バルブ２に流れる電流の極性も反転し、その過程で電流零点ができる。
【０１４０】
そして、この電流零点で副真空バルブ２が消弧し、遮断時間を短縮することができる。
【０１４１】
上述したように、本実施の形態による真空直流遮断器では、抵抗負荷の小電流遮断時に、副真空バルブ２を流れる電流が非振動になる場合であっても、可飽和リアクトル７で電流零点を作り、電流零点で副真空バルブ２が消弧して、遮断時間を短縮することが可能となる。
【０１４２】
（第１１の実施の形態）
図８は、本実施の形態による真空直流遮断器の構成例を示す回路図であり、図９と同一部分には同一符号を付してその説明を省略し、ここでは異なる部分についてのみ述べる。
【０１４３】
すなわち、本実施の形態による真空直流遮断器は、図８に示すように、前記図９におけるコンデンサ４と並列に、スイッチ８１（第２のスイッチ）とリアクトル８２（第５のリアクトル）との直列回路を接続した構成としている。
【０１４４】
次に、以上のように構成した本実施の形態による真空直流遮断器においては、コンデンサ４と並列に、スイッチ８１とリアクトル８２との直列回路を接続していることにより、抵抗負荷の小電流遮断時に、副真空バルブ２を流れる電流が非振動になる場合であっても、スイッチ８１とリアクトル８２で電流零点を作り、この電流零点で副真空バルブ２が消弧して、遮断時間を短縮することができる。
【０１４５】
すなわち、前記図１０に示す回路で示した抵抗負荷回路の小電流遮断時には、副真空バルブ２を流れる電流が非振動になるケースがあり、この場合には副真空バルブ２で電流遮断される時間が遅延する。
【０１４６】
この時、コンデンサ４の電圧は、直流の減衰波形になる。
【０１４７】
そして、この直流減衰時にスイッチ８１がＯＮすると、コンデンサ４の電荷がリアクトル８２を流れて、コンデンサ４の電圧の極性が反転する。
【０１４８】
このコンデンサ４の電圧が反転すると、副真空バルブ２に流れる電流の極性も反転し、その過程で電流零点ができる。
【０１４９】
そして、この電流零点で副真空バルブ２が消弧し、遮断時間を短縮することができる。
【０１５０】
上述したように、本実施の形態による真空直流遮断器では、抵抗負荷の小電流遮断時に、副真空バルブ２を流れる電流が非振動になる場合であっても、スイッチ８１とリアクトル８２で電流零点を作り、電流零点で副真空バルブ２が消弧して、遮断時間を短縮することが可能となる。
【０１５１】
（第１２の実施の形態）
本実施の形態による真空直流遮断器は、前述した図９に示す従来の真空直流遮断器において、前記副真空バルブ２における直流電流の裁断電流値でのサージアブソーバ６の制限電圧が、電源電圧の最大値よりも大きくなるように設定した構成としている。
【０１５２】
次に、以上のように構成した本実施の形態による真空直流遮断器においては、副真空バルブ２における直流電流の裁断電流値でのサージアブソーバ６の制限電圧が、電源電圧の最大値よりも大きくなるように設定していることにより、サージアブソーバ６を流れる電流が副真空バルブ２で遮断可能な電流値になり、副真空バルブ２の遮断時間の遅延を抑制することができる。
【０１５３】
すなわち、前記図１０に示す回路で示した抵抗負荷回路の小電流遮断時には、副真空バルブ２を流れる電流が非振動になるケースがあり、この場合には副真空バルブ２で電流遮断される時間が遅延する。
【０１５４】
この時の電流は、コンデンサ４の放電による減衰電流成分と電源電圧によるサージアブソーバ６を流れる電流との合成波になる。
【０１５５】
このため、前述した第１乃至第４の実施の形態、第７乃至第９の実施の形態により、コンデンサ４の放電電流の減衰を早めても、電源からサージアブソーバ６を介して流れる電流が、副真空バルブ２で遮断できる裁断電流よりも大きい場合には、副真空バルブ２で電流が遮断できなくなる。
【０１５６】
この点、本実施の形態では、副真空バルブ２の直流電流に対する裁断できる電流値でのサージアブソーバ６の制限電圧が電源電圧よりも高くなるように設定していることにより、サージアブソーバ６を流れる電流が副真空バルブ２で遮断可能な電流値になり、前述した第１乃至第４の実施の形態、第７乃至第９の実施の形態の対策で、副真空バルブ２の遮断時間の遅延抑制を実現することができる。
【０１５７】
上述したように、本実施の形態による真空直流遮断器では、副真空バルブ２の遮断時間の遅延抑制を実現することが可能となる。
【０１５８】
【発明の効果】
以上説明したように、本発明の真空直流遮断器によれば、小電流遮断時に真空バルブの遮断時間が遅延するのを防止することが可能となる。
【０１５９】
また、小電流遮断時に真空バルブへ大きな高周波電流が注入されるのを抑制して、真空バルブ接点の損傷を防止することが可能となる。
【図面の簡単な説明】
【図１】本発明による真空直流遮断器の第１乃至第３の実施の形態を示す回路図。
【図２】本発明による真空直流遮断器の第４の実施の形態を示す回路図。
【図３】本発明による真空直流遮断器の第５の実施の形態を示す回路図。
【図４】本発明による真空直流遮断器の第６の実施の形態を示す回路図。
【図５】本発明による真空直流遮断器の第７の実施の形態を示す回路図。
【図６】本発明による真空直流遮断器の第８の実施の形態を示す回路図。
【図７】本発明による真空直流遮断器の第１０の実施の形態を示す回路図。
【図８】本発明による真空直流遮断器の第１１の実施の形態を示す回路図。
【図９】従来の真空直流遮断器の構成例を示す回路図。
【図１０】真空直流遮断器を直流電力系統に適用した一例を示す回路図。
【符号の説明】
１…主真空バルブ
２…副真空バルブ
３…半導体スイッチ
４…コンデンサ
５…リアクトル
６…サージアブソーバ
７…可飽和リアクトル
８…抵抗
４１…コンデンサ
４２…スイッチ
４３…コンデンサ
４４…スイッチ
５１…リアクトル
５３…リアクトル
５４…リアクトル
６１…抵抗
６１…抵抗
８１…スイッチ
８２…リアクトル。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vacuum type DC circuit breaker (hereinafter referred to as a vacuum DC circuit breaker) that is installed in a DC power system and interrupts an accident current flowing through the system when a short circuit accident occurs in the DC power system, and particularly a small current. A vacuum DC circuit breaker that prevents delays in the vacuum valve's shutoff time when shutting off, and prevents damage to the vacuum valve contacts by inhibiting large high frequency currents from being injected into the vacuum valve when shutting down a small current. It is about.
[0002]
[Prior art]
Conventionally, in a DC power system such as an electric railway, when a short circuit accident or a ground fault occurs, a large DC accident current flows, and the DC power system is caused by electromagnetic force due to the accident current at that time or an arc generated at the accident point. The equipment and instruments installed in the factory are greatly damaged, and a great deal of cost and time are required for recovery.
[0003]
Therefore, in order to prevent this, a DC circuit breaker is installed in the DC power system, and it is possible to cut off the DC accident current in a short time and to minimize the damage to the equipment and instruments installed in the DC power system. Expected.
[0004]
For this purpose, the DC circuit breaker is required to cut off the accident current in the process in which the accident current increases with the occurrence of the accident, and is smaller than the finally reached accident current value (estimated short circuit current). Must be shut off.
[0005]
For example, JEC-7152 requires a DC power system with an estimated short-circuit current of 100 KA, and the peak value of the current actually cut off by the DC breaker when a short-circuit occurs is 25 KA or less.
[0006]
In the conventional DC circuit breaker, a method is adopted in which the air arc is guided into the arc chute by electromagnetic force to increase the arc voltage and the fault current is limited and interrupted by the resulting increase in arc resistance.
[0007]
However, in such a system, a loud noise is generated when the air arc is extinguished, causing noise problems, and the contacts are damaged by the arc.
[0008]
For this reason, noise countermeasures for substations installed in residential areas are required, and contact repair work by repair personnel after the interruption of the accident current has been required.
[0009]
On the other hand, in recent years, semiconductor breakers using power electronics elements such as thyristors and GTO thyristors, DC vacuum breakers using vacuum valves, etc. have been developed in place of such air-type DC breakers. Yes.
[0010]
Among these, the semiconductor circuit breaker performs the fault current interruption with the power electronics element, and therefore, the element is not damaged by the interruption, and can be used almost permanently.
[0011]
However, current power electronics devices are very expensive, have little tolerance for overvoltage and overcurrent with respect to the rated voltage and rated current of the device, and generate a large amount of heat from the device due to constant current flow. Then, it is required to use a large number of expensive power electronics elements in a series-parallel structure, which increases the overall equipment price.
[0012]
In addition, the electronic circuit that drives the power electronics element is required to operate stably. Since the electronic circuit uses elements that have problems in long-term use, such as electric field capacitors and resistors, the electronic circuit Maintenance and inspection of the circuit is essential, and the troublesome work is regarded as a problem.
[0013]
Furthermore, the electronic circuit is configured on a substrate, and if an abnormality is found during maintenance inspection, the substrate is replaced every time, resulting in an increase in maintenance costs.
[0014]
On the other hand, vacuum DC circuit breakers have been developed as being positioned between air-type DC circuit breakers and semiconductor DC circuit breakers.
[0015]
Since the arc extinguishing part of this vacuum DC circuit breaker is a vacuum valve, compared to the power electronics element, there is almost no arc extinguishing sound when the current is interrupted, and there is no need to repair the contact after the current interrupt. The feature of vacuum valves is that they are inexpensive.
[0016]
FIG. 9 is a circuit diagram showing a configuration example of this type of conventional vacuum DC circuit breaker.
[0017]
In FIG. 9, the main vacuum valve 1 and the sub vacuum valve 2 are connected in series with each other, and the illustrated left end side of the main vacuum valve 1 and the illustrated right end side of the sub vacuum valve 2 are inserted in series in a DC power system (not illustrated). Yes.
[0018]
A series circuit of a semiconductor switch 3, a capacitor 4, and a reactor 5 is connected in parallel with the main vacuum valve 1.
[0019]
Further, a surge absorber 6 which is a non-linear resistor is connected in parallel with the main vacuum valve 1.
[0020]
Furthermore, in the semiconductor switch 3, the thyristor and the diode are connected in antiparallel with each other so that the current flowing through the reactor 5 from the left to the right flows through the thyristor and the reverse current flows through the diode. A snubber circuit composed of a series circuit of a capacitor and a resistor is connected in parallel with the diode.
[0021]
In the vacuum DC circuit breaker having such a configuration, the capacitor 4 is charged in advance from a charging circuit (not shown) to a predetermined voltage (the reactor 5 side in the figure is positive), and the thyristor of the semiconductor switch 3 is in the OFF state.
[0022]
When energized, it is assumed that the main vacuum valve 1 and the sub vacuum valve 2 are closed and current flows from the left to the right in the figure (in FIG. 9, it is assumed that there is a power source on the left side in the figure and a load on the right side. ).
[0023]
In this state, assuming that a short circuit accident has occurred on the load side, the current (accident current) flowing from the power source increases toward the accident point in the main vacuum valve 1 and the sub vacuum valve 2.
[0024]
When it is detected that the increase in the accident current exceeds a predetermined value, a trip signal is output to the vacuum DC circuit breaker, and the vacuum DC circuit breaker starts a trip operation.
[0025]
That is, first, the main vacuum valve1The sub vacuum valve 2 is opened, and then the semiconductor switch 3 is turned on.
[0026]
When the semiconductor switch 3 is turned on, the electric charge stored in the capacitor 4 is discharged via the reactor-main vacuum valve 1.
[0027]
This discharge current is directed in the opposite direction to the accident current on the main vacuum bulb 1, and these combined currents form a current zero point (the values of the capacitor 4, its charging voltage, and the reactor 5 are set so as to be formed) Keep it).
[0028]
Although the current flowing through the main vacuum valve 1 is extinguished at the current zero point of the combined current, an overvoltage is generated by the electromagnetic energy possessed by the inductance on the power supply side and the load side, and the resistance of the surge absorber 6 is reduced by this overvoltage. The electromagnetic energy stored in the power supply side / load side inductance is processed by the surge absorber 6 and the flowing current is reduced, and the sub vacuum valve 2 is extinguished to complete the interruption.
[0029]
[Problems to be solved by the invention]
However, in the conventional vacuum DC circuit breaker described above, in the case where the resistance load current is interrupted, the interruption time of the sub vacuum valve 2 where the current is finally interrupted becomes longer.
[0030]
FIG. 10 is a circuit diagram showing an example in which the vacuum DC circuit breaker is applied to a DC power system.
[0031]
In the circuit as shown in FIG. 10, when the main vacuum valve 1 is extinguished as described above, the charge of the capacitor 4 flows through the resistor 8 and the power source 7 that are loads.
[0032]
At this time, if the value of the resistor 8 increases, the current flowing from the capacitor 4 via the resistor 8 and the power source 7 becomes non-vibrating, and the attenuation of the current decreases with a time constant determined by the capacitor 4 and the resistor 8. As a result, the cutoff point of the auxiliary vacuum valve 2 is delayed.
[0033]
The current flowing from the capacitor 4 to the main vacuum valve 1 is sufficiently large so that the combined current can form a current zero point when the accident current is interrupted.
[0034]
The large current from the capacitor 4 also flows when a small current equal to or lower than the rated current of the circuit breaker is interrupted.
[0035]
In this way, the formation of a large arc due to a high-frequency current between the contacts of the main vacuum valve 1 increases the damage to the contacts. This is not preferable because it leads to a reduction in the life of the vacuum DC circuit breaker.
[0036]
The purpose of the present invention is to prevent the vacuum valve shut-off time from being delayed when a small current is interrupted, and to prevent large high-frequency currents from being injected into the vacuum valve when the small current is interrupted to prevent damage to the vacuum valve contacts. An object of the present invention is to provide a vacuum DC circuit breaker that can be used.
[0037]
[Means for Solving the Problems]
  In order to achieve the above objective,Between power supply and loadIn the vacuum DC circuit breaker that is installed in and cuts off the accident current that flows to the system when an accident occurs in the DC power system,Main vacuum valve and secondaryConnect vacuum valves in series with each other,
  The mainParallel with vacuum valveNonConnect a linear resistor,
  A parallel circuit composed of a snubber circuit and a first semiconductor switch connected in parallel to the snubber circuit, a series circuit of three capacitors, and a first reactor are connected in parallel to the main vacuum valve,
  Of the three capacitors, a second semiconductor switch is connected in parallel to each of the other two capacitors excluding the capacitor having the largest capacitance, and each of the second semiconductor switches Is a thyristor and a diode connected in antiparallel to each other.
   In the invention corresponding to claim 2, the main vacuum valve and the sub vacuum valve are connected in series with each other,
  A non-linear resistor connected in parallel with the main vacuum valve;
  A parallel circuit composed of a snubber circuit and a first semiconductor switch connected in parallel to the snubber circuit, a series circuit of three capacitors, and a first reactor are connected in parallel to the main vacuum valve,
  Of the three capacitors, a second semiconductor switch is connected in parallel to each of the other two capacitors excluding the capacitor having the largest capacitance, and each of the second semiconductor switches Is a self-extinguishing element and a diode in antiparallelConnected.
[0038]
  Accordingly, claim 12Vacuum DC circuit breaker of the invention corresponding toAccording to the above, the following effects can be obtained. That is,By inserting a parallel circuit of the second semiconductor switch and the other two capacitors excluding the capacitor having the largest capacitance between the capacitor having the largest capacitance and the first reactor. Depending on the current flowing through one of the vacuum valves, the secondsemiconductorBy opening the switch, the time constant of the current flowing through the other vacuum valve is shortened. This results inThe number of parts can be reduced,The time until the current is finally interrupted by the other vacuum valve can be shortened.
  In addition, since the switches connected in parallel with the two capacitors are semiconductor switches, the second semiconductor switch can be operated at high speed.
  Furthermore, according to the invention corresponding to claim 2, as the second semiconductor switch, the self-extinguishing element and the diode are connected in antiparallel with each other, so that the non-vibration current is cut off by the other vacuum valve. Even in a region where it is impossible, it can be forcibly blocked by the self-extinguishing element.
[0043]
  Meanwhile, claims3In the invention corresponding toMain vacuum valve and sub vacuum valve are connected in series with each other,
  A non-linear resistor connected in parallel with the main vacuum valve;
  A parallel circuit composed of a snubber circuit and a first semiconductor switch connected in parallel to the snubber circuit in parallel with the main vacuum valve, a series circuit of two capacitors, a first reactor, and a second reactor Connect
  Of the two capacitors, a second semiconductor switch is connected in parallel to the first reactor and another capacitor excluding the capacitor having the largest capacitance, and the second semiconductor switch Is a thyristor and a diode connected in antiparallel to each other.
  In the invention corresponding to claim 4, the main vacuum valve and the sub vacuum valve are connected in series with each other,
  A non-linear resistor connected in parallel with the main vacuum valve;
  A parallel circuit composed of a snubber circuit and a first semiconductor switch connected in parallel to the snubber circuit in parallel with the main vacuum valve, a series circuit of two capacitors, a first reactor, and a second reactor Connect
  Of the two capacitors, a second semiconductor switch is connected in parallel to the first reactor and another capacitor excluding the capacitor having the largest capacitance, and the second semiconductor switch The self-extinguishing element and the diode are connected in reverse parallel to each other.ConnectionIt is a thing.
[0044]
  Therefore, the claims3,In the vacuum DC circuit breaker of the invention corresponding to No. 4, the secondsemiconductorBy inserting a second reactor in series with a capacitor connected in parallel with the switch, the dI / dt at the current zero point of the combined current can be reduced, and the combined current can be reliably extinguished with one vacuum valve. Can be.
[0047]
    And claims5In the invention corresponding toMain vacuum valve and sub vacuum valve are connected in series with each other,
  A non-linear resistor connected in parallel with the main vacuum valve;
  In parallel with the main vacuum valve, a parallel circuit composed of a snubber circuit and a first semiconductor switch connected in parallel with the snubber circuit, a series circuit of one capacitor and a first reactor,
A series circuit of a second semiconductor switch and a second reactor connected in parallel to the first reactor, wherein the second semiconductor switch has a thyristor and a diode connected in antiparallel to each other. It is.
  In the invention corresponding to claim 6, the main vacuum valve and the sub vacuum valve are connected in series with each other,
  A non-linear resistor connected in parallel with the main vacuum valve;
  In parallel with the main vacuum valve, a parallel circuit composed of a snubber circuit and a first semiconductor switch connected in parallel with the snubber circuit, a series circuit of one capacitor and a first reactor,
  A series circuit of a second semiconductor switch and a second reactor is connected in parallel with the first reactor, and the second semiconductor switch includes a self-extinguishing element and a diode in antiparallel to each other. InConnected.
[0048]
    Therefore, the claims5,In the invention corresponding to 6,By connecting a series circuit of a second semiconductor switch and a second reactor in parallel with the one reactor,When the small current is interrupted, dI / dt of the combined current with the high-frequency current flowing through one of the vacuum valves can be suppressed.
[0062]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0063]
(First embodiment)
FIG. 1 is a circuit diagram showing a configuration example of a vacuum DC circuit breaker according to the present embodiment. The same parts as those in FIG. 9 are denoted by the same reference numerals and description thereof is omitted, and only different parts are described here.
[0064]
That is, the vacuum DC circuit breaker according to the present embodiment includes a parallel circuit of a capacitor 41 and a switch 42 (second switch) between the capacitor 4 and the reactor 5 in FIG. And the parallel circuit of the capacitor | condenser 43 and the switch 44 (2nd switch) is set as the structure inserted in series.
[0065]
Here, of the three capacitors 4, the capacitor 41, and the capacitor 43, the capacitor 4 is a capacitor having the largest capacitance.
[0066]
Next, the operation of the vacuum DC circuit breaker according to this embodiment configured as described above will be described.
[0067]
In FIG. 1, when the fault current is interrupted, the switch 42 and the switch 44 are closed, and the semiconductor switch 3 is turned on.
[0068]
The blocking process at this time is the same as the operation described with reference to FIG.
[0069]
Next, when the small current is interrupted, the magnitude of the current flowing through the main vacuum valve 1 and the sub vacuum valve 2 is detected, and the switch 42 or the switch 44 is opened according to the magnitude (such a small magnitude). In the case of interrupting the current, it is not necessary to interrupt the current at high speed with the circuit breaker, so the switches 42 and 44 need not be opened at high speed).
[0070]
When the semiconductor switch 3 is turned on in this state, the electric charge stored in the capacitor 4 is discharged from the capacitor 41 (or the capacitor 43 or the capacitors 41 and 43) through the reactor 5, the semiconductor switch 3, and the main vacuum valve 1. .
[0071]
Then, the main vacuum bulb 1 is extinguished at the current zero point of the combined current in which the discharge current and the small current flowing in the main vacuum bulb 1 are superimposed.
[0072]
Next, the charge of the capacitor 4 is returned from the capacitor 41 (or the capacitor 43 or the capacitors 41 and 43) to the capacitor 4 via the reactor 5, the semiconductor switch 3, and the auxiliary vacuum valve 2 and from the load to the capacitor 4 via the power supply. Flowing.
[0073]
In FIG. 1, the capacitance of the capacitor 4 is represented by C_Four, The capacitance of the capacitor 41 is C₄₁, The capacitance of the capacitor 43 is C₄₃And the inductance of the reactor 5 is L_FiveAnd
[0074]
When the large current is cut off, the switches 42 and 44 are in the ON state, so that the impedance Z of the circuit in which the charge stored in the capacitor 4 is discharged.₁Can be expressed by the following equation (1).
[0075]
[Expression 1]

[0076]
Further, in the case where the switch 42 is opened when a small current is interrupted, the impedance Z of the discharge circuit₂Is the impedance (Z) of the discharge circuit in the case where both the formula (2) below and the switches 42 and 44 are opened._ThreeIs expressed by the following equation (3).
[0077]
[Expression 2]

It becomes.
[0078]
When the charging voltage of the capacitor 4 is E, the peak value I of the discharge current_pCan be expressed by the following equation (4).
[0079]
I_p= E / Z_N      (4)
Here, N = 1, 2, 3.
[0080]
As can be seen from the equation (4), by opening the switches 42 and 44 according to the current flowing through the main vacuum bulb 1, the peak value I of the discharge current is obtained._pBecomes smaller.
[0081]
Next, let us consider the current flowing through the sub-vacuum valve 2 after the main vacuum valve 1 cuts off the current with the small current interruption of the resistance load shown in FIG.
[0082]
At this time, it is assumed that the current flowing through the sub vacuum valve 2 has a large resistance value R of the resistive load and has a non-vibrating waveform.
[0083]
In the circuit shown in FIG. 10, the decay time constant τ of the current₁Is expressed by the following equation (5).
[0084]
τ₁= R ・ C_Four      ...... (5)
The time constant of the state in which the switches 42 and 44 are closed using the vacuum DC circuit breaker shown in FIG.₁It becomes.
[0085]
On the other hand, the time constant τ when the switch 42 is opened₂, And the time constant τ when both the switches 42 and 44 are opened._ThreeAre as shown in equations (6) and (7), respectively.
[0086]
[Equation 3]

[0087]
Therefore, by opening the switches 42 and 44 in accordance with the current flowing through the main vacuum valve 1, the time constant of the current flowing through the sub vacuum valve 2 is shortened. The time until the current is interrupted can be shortened.
[0088]
As described above, in the vacuum DC circuit breaker according to the present embodiment, the delay of the break point of the sub vacuum valve 2 is suppressed when a small current is interrupted, that is, the break time of the vacuum DC circuit breaker is delayed when the small current is interrupted. It becomes possible to prevent.
[0089]
(Second Embodiment)
The vacuum DC circuit breaker according to this embodiment is the same as the vacuum DC circuit breaker of the first embodiment shown in FIG. 1 described above, except that the capacitor 43 and the switch 44 are omitted, and two capacitors 4, 41 are provided. The switch 42 is connected in series and connected to the capacitor 41 in parallel.
[0090]
That is, in the vacuum DC circuit breaker of the first embodiment, two capacitors 4 and 41 are connected in series as a plurality of capacitors.
[0091]
Next, in the vacuum DC circuit breaker according to the present embodiment configured as described above, the two capacitors 4 and 41 are connected in series, so that the vacuum DC circuit breaker of the first embodiment is performed. Compared to the case, the number of parts can be reduced by the amount that the capacitor 43 and the switch 44 are omitted.
[0092]
As described above, in the vacuum DC circuit breaker according to the present embodiment, the same effects as those of the first embodiment can be obtained, and the number of parts can be reduced.
[0093]
(Third embodiment)
The vacuum DC circuit breaker according to this embodiment is the same as the switch 42, 44 connected in parallel with the capacitors 41, 43 in the vacuum DC circuit breaker of the first embodiment shown in FIG. GTO, IGBT, IEGT) and a diode are connected in antiparallel with each other.
[0094]
Next, in the vacuum DC circuit breaker according to the present embodiment configured as described above, the switches 42 and 44 connected in parallel with the capacitors 41 and 43 are connected to a thyristor (or GT0, IGBT, IEGT) and a diode. Since the semiconductor switches are connected in antiparallel to each other, the switches 42 and 44 can be operated at high speed.
[0095]
As described above, in the vacuum DC circuit breaker according to the present embodiment, the same effects as those of the first embodiment can be obtained, and the switches 42 and 44 can be operated at high speed.
[0096]
(Fourth embodiment)
FIG. 2 is a circuit diagram showing a configuration example of the vacuum DC circuit breaker according to the present embodiment. The same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. Only different parts will be described here.
[0097]
That is, in the vacuum DC circuit breaker according to the present embodiment, as shown in FIG. 2, the capacitor 43 and the switch 44 in FIG. 1 are omitted, and the reactor is connected in series with the capacitor 41 to which the switch 42 is connected in parallel. 51 (second reactor) is connected.
[0098]
Next, in the vacuum DC circuit breaker according to the present embodiment configured as described above, the reactor 51 is inserted in series with the capacitor 41 connected in parallel, so that the current zero point of the combined current is obtained. DI / dt can be reduced to ensure that the combined current can be extinguished by the main vacuum valve 1.
[0099]
That is, when the capacitance of the capacitor 41 decreases, the frequency of the high-frequency current flowing through the main vacuum valve 1 increases, the dI / dt at the current zero point of the combined current increases, and the main vacuum valve 1 is difficult to extinguish.
[0100]
In this respect, in this embodiment, in order to prevent this, the reactor 51 is inserted in series with the capacitor 41 connected in parallel, so that the dI / dt at the current zero point of the combined current is reduced. Thus, the combined current can be surely extinguished by the main vacuum valve 1.
[0101]
As described above, in the vacuum DC circuit breaker according to the present embodiment, in addition to obtaining the same effect as in the first embodiment, the main current can be surely extinguished by the main vacuum valve 1. It becomes possible to do.
[0102]
(Fifth embodiment)
FIG. 3 is a circuit diagram showing a configuration example of the vacuum DC circuit breaker according to the present embodiment. The same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. Only different parts will be described here.
[0103]
That is, in the vacuum DC circuit breaker according to the present embodiment, as shown in FIG. 3, the capacitor 43 and the switch 44 in FIG. 1 are omitted, and the capacitor 41 to which the switch 42 is connected in parallel is connected to the reactor 51 ( The second reactor is replaced with the second reactor.
[0104]
Next, in the vacuum DC circuit breaker according to the present embodiment configured as described above, the capacitor 41 to which the switch 42 is connected in parallel is replaced with the reactor 51, thereby suppressing damage to the main vacuum valve 1. In addition, the combined current can be reliably cut off.
[0105]
That is, when the semiconductor switch 3 is turned on in a state where the switch 42 is opened when the small current is cut off, the charge I stored in the capacitor 4 is discharged and the peak value I of the high-frequency current flowing in the main vacuum valve 1 is reached._PRepresents the inductance of reactor 51 as L₅₁Then, the following equation (8) is obtained.
[0106]
[Expression 4]

[0107]
Inductance L of the reactor 51₅₁Increases, the peak value I of the high-frequency current flowing through the main vacuum valve 1_PAs a result, the main vacuum valve 1 can be prevented from being damaged and the combined current can be reliably cut off.
[0108]
As described above, in the vacuum DC circuit breaker according to the present embodiment, in addition to obtaining the same effects as those of the first embodiment, damage to the main vacuum valve 1 can be suppressed and the combined current can be ensured. It becomes possible to be able to shut off.
[0109]
(Sixth embodiment)
FIG. 4 is a circuit diagram showing a configuration example of the vacuum DC circuit breaker according to the present embodiment. The same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. Only different parts will be described here.
[0110]
That is, in the vacuum DC circuit breaker according to the present embodiment, as shown in FIG. 4, the reactor 5, the capacitor 43, and the switch 44 in FIG. 1 are omitted, and the capacitor 41 to which the switch 42 is connected in parallel is provided. The reactor 53 (third reactor) is replaced, and a reactor 54 (fourth reactor) is connected in series with a switch 42 to which the reactor 53 is connected in parallel.
[0111]
Next, in the vacuum DC circuit breaker according to the present embodiment configured as described above, the switch 42 is arranged in series with the reactor 54, and the reactor 53 is connected in parallel with the series circuit, so that a small current is obtained. It is possible to suppress dI / dt of the combined current with the high-frequency current flowing through the main vacuum valve 1 when shut off.
[0112]
That is, in the case where the main vacuum valve 1 cuts off a large current, the switch 42 is closed, and the reactors 53 and 54 are connected in parallel. When the small current is cut off, the switch 42 is opened so that only the reactor 53 has a current. Flowing.
[0113]
Here, the inductance of the reactor 53 is L₅₃, The inductance of the reactor 54 is L₅₄And L₅₃> L₅₄Thus, dI / dt of the combined current with the high-frequency current flowing through the main vacuum valve 1 when a small current is interrupted can be suppressed.
[0114]
As described above, in the vacuum DC circuit breaker according to the present embodiment, in addition to obtaining the same effect as the first embodiment, in addition to the high-frequency current flowing through one of the vacuum valves when a small current is interrupted, DI / dt of the generated current can be suppressed.
[0115]
(Seventh embodiment)
FIG. 5 is a circuit diagram showing a configuration example of the vacuum DC circuit breaker according to the present embodiment. The same parts as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is omitted. Only different parts will be described here.
[0116]
That is, the vacuum DC circuit breaker according to the present embodiment, as shown in FIG. 5, in parallel with the capacitor 41 in which the switch 42 in FIG. 1 is connected in parallel and the capacitor 43 in which the switch 44 is connected in parallel, The resistor 61 and the resistor 62 are connected.
[0117]
Next, in the vacuum DC circuit breaker according to the present embodiment configured as described above, the switches 42 and 44 are connected in parallel with the capacitors 41 and 43 connected in parallel, so that the resistors 61 and 62 are connected. The residual charges remaining in the capacitors 41 and 43 after the two vacuum valves 1 and 2 are shut off are discharged by the resistors 61 and 62, and then the switches 42 and 44 are turned on to damage the switches 42 and 44 or the capacitors 41 and 43. Can be eliminated.
[0118]
That is, residual charges remain in the capacitors 41 and 43 after the main vacuum valve 1 and the sub vacuum valve 2 are shut off.
[0119]
If the switches 42 and 44 are closed in this state, the residual charges are discharged through the switches 42 and 44, and the switches 42 and 44 or the capacitors 41 and 43 are damaged.
[0120]
In this respect, in the present embodiment, in order to eliminate this, the residual charges are discharged by the resistors 61 and 62, and then the switches 42 and 44 are turned on to damage the switches 42 and 44 or the capacitors 41 and 43. You can eliminate it.
[0121]
As described above, in the vacuum DC circuit breaker according to the present embodiment, in addition to obtaining the same effect as in the first embodiment, the switches 42 and 44 or the capacitors 41 and 43 are damaged. It can be eliminated.
[0122]
(Eighth embodiment)
FIG. 6 is a circuit diagram showing a configuration example of the vacuum DC circuit breaker according to the present embodiment. The same parts as those in FIG. 9 are denoted by the same reference numerals, and the description thereof is omitted. Only different parts will be described here.
[0123]
That is, the vacuum DC circuit breaker according to the present embodiment has a configuration in which the insertion position of the semiconductor switch 3 in FIG. 9 is arranged on the power supply side as shown in FIG.
[0124]
Next, in the vacuum DC circuit breaker according to the present embodiment configured as described above, the voltage applied to the semiconductor switch 3 can be reduced by setting the insertion position of the semiconductor switch 3 to the power supply side.
[0125]
That is, in the circuit having the configuration shown in FIG._sAnd the charging voltage E of the capacitor 4, the ground potential V of the semiconductor switch 3_swIs
V_sw= V_s+ E
It becomes.
[0126]
In contrast, when the semiconductor switch 3 is installed on the power supply side as in the present embodiment shown in FIG.
V_sw= V_s
Thus, the voltage applied to the semiconductor switch 3 can be reduced.
[0127]
As described above, in the vacuum DC circuit breaker according to the present embodiment, the voltage applied to the semiconductor switch 3 can be reduced.
[0128]
(Ninth embodiment)
The vacuum DC circuit breaker according to the present embodiment is the same as the conventional vacuum DC circuit breaker shown in FIG. 9 described above, but the thyristor of the semiconductor switch 3 is a self-extinguishing element such as GTO, IGBT, IEGT, or the like. The switch 3 is configured to use a semiconductor switch incorporating a self-extinguishing element.
[0129]
Next, in the vacuum DC circuit breaker according to the present embodiment configured as described above, the semiconductor switch 3 is a semiconductor switch incorporating a self-extinguishing element, so that the non-oscillating current is subvacuum. Even in a region that cannot be blocked by the valve 2, it can be forcibly blocked by a self-extinguishing element.
[0130]
That is, when the current of the resistive load circuit shown in the circuit of FIG. 10 is cut off, there is a case where the current flowing through the sub vacuum valve 2 becomes non-vibrating. In this case, the time during which the current is cut off by the sub vacuum valve 2 Delay.
[0131]
In this respect, in the present embodiment, in order to solve this problem, a non-vibration current cannot be interrupted by the sub-vacuum valve 2 by using the semiconductor switch 3 incorporating a self-extinguishing element. Also, it can be forcibly cut off by a self-extinguishing element.
[0132]
As described above, in the vacuum DC circuit breaker according to the present embodiment, even if the non-vibration current cannot be interrupted by the sub vacuum valve 2, it can be forcibly interrupted by the self-extinguishing element.
[0133]
(Tenth embodiment)
FIG. 7 is a circuit diagram illustrating a configuration example of the vacuum DC circuit breaker according to the present embodiment. The same parts as those in FIG. 9 are denoted by the same reference numerals, and the description thereof is omitted. Only different parts will be described here.
[0134]
That is, the vacuum DC circuit breaker according to this embodiment has a configuration in which a saturable reactor 7 is connected in parallel with the main vacuum valve 1 in FIG. 9 as shown in FIG.
[0135]
Next, in the vacuum DC circuit breaker according to the present embodiment configured as described above, the saturable reactor 7 is connected in parallel with the main vacuum valve 1, so that the sub vacuum Even when the current flowing through the valve 2 becomes non-vibrating, the saturable reactor 7 creates a current zero point, and the sub-vacuum valve 2 is extinguished at this current zero point, thereby shortening the cutoff time.
[0136]
That is, when a small current is interrupted in the resistance load circuit shown in the circuit shown in FIG. 10, there is a case where the current flowing through the sub vacuum valve 2 does not vibrate. In this case, the time during which the current is interrupted by the sub vacuum valve 2 Is delayed.
[0137]
At this time, the voltage between the electrodes of the main vacuum valve 1 is substantially the same voltage as that of the capacitor 4 and has a direct current decay waveform.
[0138]
When this DC decay waveform is applied to the saturable reactor 7, the saturable reactor 7 is saturated, the charge of the capacitor 4 flows through the saturable reactor 7, and the polarity of the voltage of the capacitor 4 is reversed.
[0139]
When the voltage of the capacitor 4 is reversed, the polarity of the current flowing through the sub vacuum valve 2 is also reversed, and a current zero point is formed in the process.
[0140]
Then, the auxiliary vacuum valve 2 is extinguished at this current zero point, and the interruption time can be shortened.
[0141]
As described above, in the vacuum DC circuit breaker according to the present embodiment, even when the current flowing through the sub vacuum valve 2 becomes non-vibrating when a small current is interrupted by the resistive load, the saturable reactor 7 sets the current zero point. The sub-vacuum valve 2 is extinguished at the current zero point, and the interruption time can be shortened.
[0142]
(Eleventh embodiment)
FIG. 8 is a circuit diagram showing a configuration example of the vacuum DC circuit breaker according to the present embodiment. The same parts as those in FIG. 9 are denoted by the same reference numerals and description thereof is omitted, and only different parts are described here.
[0143]
That is, as shown in FIG. 8, the vacuum DC circuit breaker according to the present embodiment is a series of a switch 81 (second switch) and a reactor 82 (fifth reactor) in parallel with the capacitor 4 in FIG. The circuit is connected.
[0144]
Next, in the vacuum DC circuit breaker according to the present embodiment configured as described above, a series circuit of the switch 81 and the reactor 82 is connected in parallel with the capacitor 4 so as to cut off the small current of the resistive load. Sometimes, even when the current flowing through the sub vacuum valve 2 becomes non-vibrating, a current zero point is created by the switch 81 and the reactor 82, and the sub vacuum valve 2 is extinguished at this current zero point, thereby shortening the cutoff time. be able to.
[0145]
That is, when a small current is interrupted in the resistance load circuit shown in the circuit shown in FIG. 10, there is a case where the current flowing through the sub vacuum valve 2 does not vibrate. In this case, the time during which the current is interrupted by the sub vacuum valve 2 Is delayed.
[0146]
At this time, the voltage of the capacitor 4 has a direct current decay waveform.
[0147]
When the switch 81 is turned on during the DC decay, the charge of the capacitor 4 flows through the reactor 82 and the voltage polarity of the capacitor 4 is inverted.
[0148]
When the voltage of the capacitor 4 is reversed, the polarity of the current flowing through the sub vacuum valve 2 is also reversed, and a current zero point is formed in the process.
[0149]
Then, the auxiliary vacuum valve 2 is extinguished at this current zero point, and the interruption time can be shortened.
[0150]
As described above, in the vacuum DC circuit breaker according to the present embodiment, even when the current flowing through the sub vacuum valve 2 becomes non-vibrating when a small current is cut off from the resistive load, the current zero point is generated by the switch 81 and the reactor 82. The sub vacuum valve 2 is extinguished at the current zero point, and the interruption time can be shortened.
[0151]
(Twelfth embodiment)
The vacuum DC circuit breaker according to this embodiment is the same as the conventional vacuum DC circuit breaker shown in FIG. 9 described above, wherein the limiting voltage of the surge absorber 6 at the cutting current value of the DC current in the sub vacuum valve 2 is the power The configuration is set to be larger than the maximum value.
[0152]
Next, in the vacuum DC circuit breaker according to the present embodiment configured as described above, the limit voltage of the surge absorber 6 at the cutting current value of the DC current in the sub vacuum valve 2 is larger than the maximum value of the power supply voltage. By setting so as to be, the current flowing through the surge absorber 6 becomes a current value that can be interrupted by the sub-vacuum valve 2, and the delay of the shut-off time of the sub-vacuum valve 2 can be suppressed.
[0153]
That is, when a small current is interrupted in the resistance load circuit shown in the circuit shown in FIG. 10, there is a case where the current flowing through the sub vacuum valve 2 does not vibrate. In this case, the time during which the current is interrupted by the sub vacuum valve 2 Is delayed.
[0154]
The current at this time is a composite wave of the decay current component due to the discharge of the capacitor 4 and the current flowing through the surge absorber 6 due to the power supply voltage.
[0155]
For this reason, even if the decay of the discharge current of the capacitor 4 is accelerated by the first to fourth embodiments and the seventh to ninth embodiments, the current flowing from the power source via the surge absorber 6 is When the cutting current that can be cut off by the sub vacuum valve 2 is larger than the cutting current, the current cannot be cut off by the sub vacuum valve 2.
[0156]
In this respect, in the present embodiment, the limit voltage of the surge absorber 6 at a current value that can be cut with respect to the direct current of the sub vacuum valve 2 is set to be higher than the power supply voltage, so that the surge absorber 6 flows. The current becomes a current value that can be interrupted by the sub-vacuum valve 2, and by the countermeasures of the first to fourth embodiments and the seventh to ninth embodiments described above, the delay time of the sub-vacuum valve 2 is suppressed. Can be realized.
[0157]
As described above, in the vacuum DC circuit breaker according to the present embodiment, it is possible to realize delay suppression of the shut-off time of the sub vacuum valve 2.
[0158]
【The invention's effect】
As described above, according to the vacuum direct current circuit breaker of the present invention, it is possible to prevent delay of the shutoff time of the vacuum valve when a small current is interrupted.
[0159]
Further, it is possible to prevent large vacuum current from being injected into the vacuum valve when a small current is interrupted, thereby preventing damage to the vacuum valve contact.
[Brief description of the drawings]
FIG. 1 is a circuit diagram showing first to third embodiments of a vacuum DC circuit breaker according to the present invention.
FIG. 2 is a circuit diagram showing a fourth embodiment of a vacuum DC circuit breaker according to the present invention.
FIG. 3 is a circuit diagram showing a fifth embodiment of a vacuum DC circuit breaker according to the present invention.
FIG. 4 is a circuit diagram showing a sixth embodiment of a vacuum DC circuit breaker according to the present invention.
FIG. 5 is a circuit diagram showing a seventh embodiment of the vacuum DC circuit breaker according to the present invention.
FIG. 6 is a circuit diagram showing an eighth embodiment of a vacuum DC circuit breaker according to the present invention.
FIG. 7 is a circuit diagram showing a tenth embodiment of a vacuum DC circuit breaker according to the present invention.
FIG. 8 is a circuit diagram showing an eleventh embodiment of a vacuum DC circuit breaker according to the present invention.
FIG. 9 is a circuit diagram showing a configuration example of a conventional vacuum DC circuit breaker.
FIG. 10 is a circuit diagram showing an example in which a vacuum DC circuit breaker is applied to a DC power system.
[Explanation of symbols]
1 ... Main vacuum valve
2 ... Sub vacuum valve
3 ... Semiconductor switch
4 ... Capacitor
5 ... Reactor
6. Surge absorber
7 ... Saturable reactor
8 ... Resistance
41 ... Capacitor
42 ... Switch
43 ... Capacitor
44 ... Switch
51 ... Reactor
53 ... Reactor
54 ... Reactor
61 ... Resistance
61 ... Resistance
81 ... Switch
82 ... Reactor.

Claims (6)

In a vacuum DC circuit breaker that is installed between the power supply and load of a DC power system and interrupts the accident current that flows through the system when an accident occurs in the DC power system,
Main vacuum valve and sub vacuum valve are connected in series with each other,
A non-linear resistor connected in parallel with the main vacuum valve;
A parallel circuit composed of a snubber circuit and a first semiconductor switch connected in parallel to the snubber circuit, a series circuit of three capacitors, and a first reactor are connected in parallel to the main vacuum valve,
Of the three capacitors, a second semiconductor switch is connected in parallel to each of the other two capacitors excluding the capacitor having the largest capacitance, and each of the second semiconductor switches Is a vacuum DC circuit breaker characterized in that a thyristor and a diode are connected in reverse parallel to each other. In a vacuum DC circuit breaker that is installed between the power supply and load of a DC power system and interrupts the accident current that flows through the system when an accident occurs in the DC power system,
Main vacuum valve and sub vacuum valve are connected in series with each other,
A non-linear resistor connected in parallel with the main vacuum valve;
A parallel circuit composed of a snubber circuit and a first semiconductor switch connected in parallel to the snubber circuit, a series circuit of three capacitors, and a first reactor are connected in parallel to the main vacuum valve,
Of the three capacitors, a second semiconductor switch is connected in parallel to each of the other two capacitors excluding the capacitor having the largest capacitance, and each of the second semiconductor switches Is a vacuum DC circuit breaker characterized in that a self-extinguishing element and a diode are connected in reverse parallel to each other. In a vacuum DC circuit breaker that is installed between the power supply and load of a DC power system and interrupts the accident current that flows through the system when an accident occurs in the DC power system,
Main vacuum valve and sub vacuum valve are connected in series with each other,
A non-linear resistor connected in parallel with the main vacuum valve;
A parallel circuit comprising a snubber circuit and a first semiconductor switch connected in parallel to the snubber circuit in parallel with the main vacuum valve, a series circuit of two capacitors, a first reactor, and a second reactor Connect the
Of the two capacitors, a second semiconductor switch is connected in parallel to the first reactor and another capacitor excluding the capacitor having the largest capacitance, and the second semiconductor switch Is a vacuum DC circuit breaker characterized in that a thyristor and a diode are connected in reverse parallel to each other. In a vacuum DC circuit breaker that is installed between the power supply and load of a DC power system and interrupts the accident current that flows through the system when an accident occurs in the DC power system,
Main vacuum valve and sub vacuum valve are connected in series with each other,
A non-linear resistor connected in parallel with the main vacuum valve;
A parallel circuit comprising a snubber circuit and a first semiconductor switch connected in parallel to the snubber circuit in parallel with the main vacuum valve, a series circuit of two capacitors, a first reactor, and a second reactor Connect the
Of the two capacitors, a second semiconductor switch is connected in parallel to the first reactor and another capacitor excluding the capacitor having the largest capacitance, and the second semiconductor switch Is a vacuum DC circuit breaker characterized in that a self-extinguishing element and a diode are connected in reverse parallel to each other. In a vacuum DC circuit breaker that is installed between the power supply and load of a DC power system and interrupts the accident current that flows through the system when an accident occurs in the DC power system,
Main vacuum valve and sub vacuum valve are connected in series with each other,
A non-linear resistor connected in parallel with the main vacuum valve;
In parallel with the main vacuum valve, a parallel circuit composed of a snubber circuit and a first semiconductor switch connected in parallel with the snubber circuit, a series circuit of one capacitor and a first reactor,
A series circuit of a second semiconductor switch and a second reactor is connected in parallel to the first reactor, and the second semiconductor switch has a thyristor and a diode connected in antiparallel to each other. Vacuum DC circuit breaker characterized by In a vacuum DC circuit breaker that is installed between the power supply and load of a DC power system and interrupts the accident current that flows through the system when an accident occurs in the DC power system,
Main vacuum valve and sub vacuum valve are connected in series with each other,
A non-linear resistor connected in parallel with the main vacuum valve;
In parallel with the main vacuum valve, a parallel circuit composed of a snubber circuit and a first semiconductor switch connected in parallel with the snubber circuit, a series circuit of one capacitor and a first reactor,
A series circuit of a second semiconductor switch and a second reactor is connected in parallel with the first reactor, and the second semiconductor switch includes a self-extinguishing element and a diode in antiparallel to each other. A vacuum DC circuit breaker characterized by being connected to

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