JP4388191B2

JP4388191B2 - Power switching device

Info

Publication number: JP4388191B2
Application number: JP2000067306A
Authority: JP
Inventors: 大作佐藤
Original assignee: Osaka Gas Co Ltd
Current assignee: Osaka Gas Co Ltd
Priority date: 2000-03-10
Filing date: 2000-03-10
Publication date: 2009-12-24
Anticipated expiration: 2020-03-10
Also published as: JP2001258179A

Description

【０００１】
【発明の属する技術分野】
本発明は、負荷に電力を供給する交流電源を２つの電源の間で切り替える電源切替装置に関し、例えば、負荷に電力を供給する電源を商用電源と自家用発電設備との間で切り替える電源切替装置に関する。
【０００２】
【従来の技術】
コジェネレーション等の自家用発電設備を有する需要家（以下「自家発需要家」という）において、図１１に示すように昼間は自家用発電設備から、夜間は商用電源から電力を負荷に供給するために、負荷に電力を供給する電源（以下「電力供給源」という）を自家用発電設備と商用電源との間で切り替える電源切替装置が使用されている。この電源切替装置は、負荷への電力の供給を停止することなく、かつ、２つの電源が同時に負荷に接続される状態すなわち２つの電源間でのオーバラップ（以下「電源オーバラップ」という）を生じさせることなく、電力供給源を切り替えることが要求される。
【０００３】
図１２は、上記のように負荷への電力供給の停止も電源オーバラップも招くことなく２つの電源の間で電力供給源を切り替える従来の電源切替装置の概略構成を示すブロック図である。この電源切替装置６は、負荷７へ電力を供給する電源を第１の電源１と第２の電源２との間で切り替えるものであって、第１の開閉部６１および第２の開閉部６２という２つの開閉部と、制御装置６４とを備えている。第１の開閉部６１の一端は第１の電源１に、第２の開閉部６２の一端は第２の電源２にそれぞれ接続され、第１および第２の開閉部６１，６２の他端は互いに接続されかつ負荷７に接続されている。制御装置６４は、負荷への電力供給の停止も電源オーバラップも招くことなく第１および第２の電源１，２の間で電力供給源を切り替えるべく、第１および第２の開閉部６１，６２を相反的に開閉させる。
【０００４】
一般に電源切替装置は、スイッチの形式により半導体式と機械式とハイブリッド式とに分類される。半導体式ではサイリスタなどの半導体スイッチにより開閉部が構成され、機械式では機械式の開閉器により開閉部が構成され、ハイブリッド式では半導体スイッチと機械式開閉器との組み合わせにより開閉部が構成される。ところで、電源オーバラップを回避しつつ電力供給源を切り替えようとすると、その切替の際に、負荷がいずれの電源からも瞬間的に切り離された状態（以下「瞬断状態」という）となる。この瞬断状態の期間が長いと負荷への供給電圧の低下が許容範囲を越えて負荷に影響を及ぼす。半導体式やハイブリッド式の電源切替装置では、電源切替時における瞬断状態の期間（以下「切替時間」という）はマイクロ秒のオーダであるため、通常、電源切替によって負荷へ影響が及ぶことはない。しかし、半導体スイッチはＯＮ時の抵抗が大きいため、半導体式やハイブリッド式の電源切替装置は効率の点で機械式の電源切替装置に比べ劣っている。これに対し機械式の電源切替装置は、効率の点で有利ではあるが、下記に述べるように、電源切替時における瞬断状態の期間である切替時間が長くなる（例えば２０ｍｓ程度になる）という問題を有している。
【０００５】
【発明が解決しようとする課題】
機械式の開閉器では、閉極状態において交流電流が流れているときに遮断指令を受けると、その交流電流がゼロとなる時点（以下「電流ゼロ点」という）で開極状態となる。従来の一般的な機械式開閉器では、閉極状態において遮断指令を受け取ってから接触子が機械的に離れた状態となるまでの時間（「開極時間」と呼ばれる）が長いため（通常５０ｍｓ以上、すなわち６０Ｈｚ電源における３サイクル以上）、開極状態となる電流ゼロ点を特定することができない。ところで、電源切替時に電源オーバラップを回避するには、機械式の電源切替装置における２つの開閉器のうち閉極状態にあった開閉器（以下「閉状態開閉器」という）が開極状態になった後に他方の開閉器である開極状態にあった開閉器（以下「開状態開閉器」という）が閉極状態になるようにしなければならない。したがって、電源切替装置において従来の一般的な機械式開閉器を用いた場合には、切替指令を受けてから開状態開閉器に閉極動作を開始させるまでの時間を長くしなければならない。その結果、電源切替時における瞬断状態の期間（切替時間）も長くなり（例えば２０ｍｓ）、電源切替によって負荷が影響を受ける。
【０００６】
そこで本発明では、電源オーバラップを回避しつつ、かつ、負荷に影響を与えるような長い切替時間を生じさせることなく、交流電源を切り替えることのできる機械式の電源切替装置を提供することを目的とする。
【０００７】
【課題を解決するための手段および発明の効果】
第１の発明は、負荷に電力を供給する交流電源を切替指令に応じて第１および第２の電源の間で切り換える電源切替装置であって、
前記第１の電源と前記負荷との間に挿入され、閉極状態において前記第１の電源から前記負荷へ流れる電流が零になる電流ゼロ点の時間間隔である電流ゼロ点間隔よりも開極時間が短い機械式の第１の開閉器と、
前記第２の電源と前記負荷との間に挿入され、閉極状態において前記第２の電源から前記負荷へ流れる電流が零になる電流ゼロ点の時間間隔である電流ゼロ点間隔よりも開極時間が短い機械式の第２の開閉器と、
前記切替指令を受け取り、前記第１および第２の電源の前記負荷へ同時接続が回避されるように、前記切替指令に応じて前記第１および第２の開閉器を相反的に開閉させる制御手段と、
を備え、
前記制御手段は、前記切替指令を受け取ると、前記第１および第２の開閉器のうち閉極状態にある閉状態開閉器に直ちに開極動作を開始させるとともに、前記第１および第２の開閉器のうち開極状態にある開状態開閉器に、前記閉状態開閉器の開極動作の完了後であって当該開極動作の完了時点から予め決められた切替時間だけ経過する前に当該開状態開閉器の閉極動作が完了するように、当該閉極動作を開始させることを特徴とする。
【０００８】
上記第１の発明によれば、機械式の電源切替装置により切替指令に応じて２つの交流電源の間で電力供給源が切り換えられ、この電源切替の際に開状態開閉器は、閉状態開閉器の開極動作の完了後であって当該開極動作の完了時点から予め決められた切替時間だけ経過する前に、閉極動作を完了する。ところで後述のように、電源切替において切替時間（瞬断状態の期間）が１０ｍｓ以下であれば、負荷の種類を問わず負荷に影響が及ばないことが知られている。また、上記第１の発明における第１および第２の開閉器の開極時間は電流ゼロ点間隔よりも短いため、切替指令を受け取ってから前記開極動作の完了時点までの時間（開極動作時間）の変動幅は電流ゼロ点間隔であり、電流ゼロ点間隔は、第１および第２の電源として例えば６０Ｈｚの３相交流電源を想定した場合、約２．８ｍｓである。したがって、負荷に影響が及ばないような短い切替時間を設定したとしても、開極動作時間の変動に拘わらず、閉状態開閉器の開極動作の完了後であって当該開極動作の完了時点からその切替時間だけ経過する前に開状態開閉器の閉極動作が完了するように開状態開閉器に閉極動作を開始させることが可能である。よって、上記第１の発明において、負荷の種類に応じて切替時間を適切に設定することにより（負荷の種類が限定されない場合は１０ｍｓ以下に設定）、電源オーバラップを回避しつつ、電源切替による負荷への影響を抑えることができる。
【０００９】
第２の発明は、第１の発明において、
前記制御手段が前記切替指令を受け取った受取時点から前記開極動作の完了時点までの時間間隔である開極動作時間の最小値として最短開極動作時間を定義し、かつ当該開極動作時間の最大値として最長開極動作時間を定義するものとすると、前記制御手段は、前記切替指令の前記受取時点から前記最長開極動作時間だけ経過した後であって前記切替指令の前記受取時点から前記最短開極動作時間と前記切替時間との和の時間だけ経過する前に前記開状態開閉器の閉極動作が完了するように、当該閉極動作を前記開状態開閉器に開始させることを特徴とする。
【００１０】
上記第２の発明によれば、切替指令の受取時点から最長開極動作時間だけ経過した後であって、切替指令の受取時点から最短開極動作時間と切替時間との和の時間だけ経過する前に、前記開状態開閉器の閉極動作が完了する。このため、負荷の種類に応じて切替時間を適切に設定することにより（負荷の種類が限定されない場合は１０ｍｓ以下に設定）、開極動作時間の変動に拘わらず、電源オーバラップを回避しつつ、電源切替による負荷への影響を抑えることができる。
【００１１】
第３の発明は、第１の発明において、
前記制御手段が前記切替指令を受け取った受取時点から前記開極動作の完了時点までの時間間隔である開極動作時間の最大値として最長開極動作時間を定義するものとすると、前記制御手段は、前記切替指令の前記受取時点から前記最長開極動作時間だけ経過した直後の期間であって前記切替時間と前記電流ゼロ点間隔との差に相当する期間に前記開状態開閉器の閉極動作が完了するように、当該閉極動作を前記開状態開閉器に開始させることを特徴とする。
【００１２】
上記第３の発明によれば、前記切替指令の前記受取時点から前記最長開極動作時間だけ経過した直後の期間であって前記切替時間と前記電流ゼロ点間隔との差に相当する期間に前記開状態開閉器の閉極動作が完了する。そして上記第３の発明では、第１および第２の開閉器の開極時間は電流ゼロ点間隔よりも短いため、開極動作時間の変動幅は電流ゼロ点間隔である。したがって、負荷の種類に応じて切替時間を適切に設定することにより（負荷の種類が限定されない場合は１０ｍｓ以下に設定）、開極動作時間の変動に拘わらず、電源オーバラップを回避しつつ、電源切替による負荷への影響を抑えることができる。
【００１３】
第４の発明は、第１ないし第３の発明のいずれかにおいて、
前記第１および第２の電源は、周波数が６０Ｈｚの３相交流電源であり、
前記制御手段は、前記切替指令を受け取ってから６．８ミリ秒に前記閉状態開閉器の開極時間を加算した時間だけ経過した後であって、前記切替指令を受け取ってから４．０ミリ秒に前記閉状態開閉器の開極時間および前記切替時間を加算した時間だけ経過する前に、前記開状態開閉器の閉極動作が完了するように、当該閉極動作を前記開状態開閉器に開始させることを特徴とする。
【００１４】
上記第４の発明では、第１および第２の電源は周波数が６０Ｈｚの３相交流電源であるため、電流ゼロ点間隔は約２．８ｍｓである。また、機械式の開閉器である高速度３相遮断器において３相交流電源を遮断すると、１相目のバルブが開極してから約４ｍｓ後には残りの２相のバルブが開極状態となっていることが、後述の実験結果よって検証されている。したがって、開極動作時間は、最長で"開極時間＋２．８＋４"［ｍｓ］であり、最短で"開極時間＋４"［ｍｓ］である。これに対応して上記第４の発明では、切替指令を受け取ってから６．８ミリ秒に開極時間を加算した時間だけ経過した後であって、切替指令を受け取ってから４ミリ秒に開極時間および切替時間を加算した時間だけ経過する前に、開状態開閉器の閉極動作が完了するように構成されている。したがって、上記第４の発明によれば、負荷の種類に応じて切替時間を適切に設定することにより（負荷の種類が限定されない場合は１０ｍｓ以下に設定）、開極動作時間の変動に拘わらず、電源オーバラップを回避しつつ、電源切替による負荷への影響を抑えることができる。
【００１５】
第５の発明は、負荷に電力を供給する交流電源を切替指令に応じて第１および第２の電源の間で切り換える電源切替装置であって、
前記第１の電源と前記負荷との間に挿入された機械式の第１の開閉器と、
前記第２の電源と前記負荷との間に挿入された機械式の第２の開閉器と、
前記切替指令を受け取り、前記第１および第２の電源の前記負荷へ同時接続が回避されるように、前記切替指令に応じて前記第１および第２の開閉器を相反的に開閉させる制御手段と、
前記第１および第２の開閉器のうち閉極状態にある閉状態開閉器が開極動作を開始したときに当該開極動作の完了を検出する検出手段と、
を備え、
前記第１および第２の開閉器の閉極動作時間は、予め決められた切替時間よりも短く、
前記制御手段は、前記切替指令を受け取ると、前記第１および第２の開閉器のうち閉状態開閉器に直ちに開極動作を開始させ、当該開極動作の完了が前記検出手段によって検出された時点で、前記第１および第２の開閉器のうち開極状態にある開状態開閉器に閉極動作を開始させることを特徴とする。
【００１６】
上記第５の発明によれば、機械式の電源切替装置により切替指令に応じて２つの交流電源の間で電力供給源が切り換えられ、この電源切替の際に開状態開閉器は、閉状態開閉器の開極動作の完了が前記検出手段によって検出された時点で閉極動を開始する。そして上記第５の発明における第１および第２の開閉器の閉極動作時間は、予め決められた切替時間よりも短い。よって、上記第５の発明において、負荷の種類に応じて切替時間を適切に設定し（負荷の種類が限定されない場合は１０ｍｓ以下に設定）、その設定に応じた閉極動作時間を有する開閉器を使用することにより、開極動作時間の変動に拘わらず、電源オーバラップを回避しつつ、電源切替による負荷への影響を抑えることができる。
【００１７】
第６の発明は、第１ないし第５の発明のいずれかにおいて、
前記切替時間は１０ミリ秒以下であることを特徴とする。
【００１８】
後述のように、電源切替において切替時間（瞬断状態の期間）が１０ｍｓ以下であれば、負荷の種類を問わず負荷に影響が及ばないことが知られている。したがって、上記第５の発明によれば、電源オーバラップを回避しつつ、負荷の種類を問わず電源切替による負荷への影響を抑えることができる。
【００１９】
【発明の実施の形態】
＜基礎検討＞
まず、本発明の実施形態に係る電源切替装置を実現するための基礎検討について説明する。
【００２０】
（１）切替時間
電気共同研究会（社団法人）より平成２年７月１８日に発行された「電気協同研究」第４６巻第３号において瞬時電圧低下対策専門委員会による論文“瞬時電圧低下対策”が公表されており、ここには、各種負荷機器の瞬時電圧低下の影響例を示す図３が開示されている。図３によれば、いずれの負荷機器についても、電圧低下の継続時間が１０ｍｓ（０．０１秒）以下であれば、電圧低下の程度によらずその電圧低下は負荷に影響しないことがわかる。したがって、電源切替装置による電源切替時の瞬断状態の期間すなわち切替時間が１０ｍｓ以下であれば、その電源切替は負荷には影響を及ぼさない。
【００２１】
（２）開極時間と開極動作時間
前述のように、従来の一般的な機械式開閉器では、開極時間が長いため（通常５０ｍｓ以上）、閉極状態において遮断指令を受けてから開極状態（電気的に閉じた状態）になるまでの時間である開極動作時間が確定しなかった。しかし、近年、３相３台の真空バルブのそれぞれに電磁反発装置が付加され、開極時間の非常に短い３相一括形の交流遮断器が開発されている。このような高速度３相遮断器は、例えば特開平９−１８０６００号公報に開示されており、その開極時間は１ｍｓ程度であって従来に比べ大幅に短縮されている。ところで、例えば６０Ｈｚの３相交流の場合、図４に示すように、１サイクルの間隔は１ｓ／６０Ｈｚ＝０．０１６６…［ｓ］すなわち約１６．７ｍｓであり、電流ゼロ点間隔は１ｓ／６０Ｈｚ／３相／２＝０．００２７７…［ｓ］すなわち約２．８ｍｓである。したがって、上記の高速度３相遮断器の開極時間は電流ゼロ点間隔に比べて十分に短い。このように開極時間が電流ゼロ点間隔よりも短い開閉器（遮断器）では、上記従来の一般的な機械式開閉器とは異なり、開極動作時間が確定する。
【００２２】
すなわち、開極時間が電流ゼロ点間隔よりも短い開閉器では、図５に示すように、遮断指令を受けた時点からその時点以降の直近の電流ゼロ点までの時間が開極時間よりも長い場合（時点Ａで遮断指令を受けた場合）には、その直近の電流ゼロ点Ｃ01で開極状態となる。ただし図５では、直近の電流ゼロ点Ｃ01よりも開極時間だけ前の時点をＴ１としている。また、遮断指令を受けた時点からその時点以降の直近の電流ゼロ点までの時間が開極時間よりも短い場合（時点Ｂで遮断指令を受けた場合）には、その直近の電流ゼロ点Ｃ01で開極状態とはならないが、その直近の電流ゼロ点の次の電流ゼロ点Ｃ02で必ず開極状態となる。したがって、遮断指令の時点が決まれば開極動作時間が確定する。しかし、図５からわかるように、開極動作時間は、遮断指令を受けた時点と電流ゼロ点との時間的関係によって変動し、電流ゼロ点から開極時間だけ前の時点Ｔ１の直前に遮断指令を受け取った場合に最短となり、その時点Ｔ１の直後に遮断指令を受け取った場合に最長となる。そして開極動作時間は、最短で開極時間に等しく、最長で開極時間と電流ゼロ点間隔との和に相当する時間となる。したがって、開極時間が電流ゼロ点間隔よりも短い機械式開閉器では、開極動作時間の変動幅は電流ゼロ点間隔となる。
【００２３】
なお、図５は、単相の交流電源に対する機械式開閉器（または３相遮断器を構成する１つのバルブ）について開極動作のタイミングを示したものであるが、３相３台のバルブを含む３相遮断器において遮断指令を受けた後にいずれか１相のバルブが開極状態となるときのタイミングも同様である。すなわち、遮断指令を受けた時点からその時点以降の直近の電流ゼロ点までの時間が開極時間よりも長い場合には、その直近の電流ゼロ点で３相のうちいずれか１相のバルブが開極状態となる。一方、遮断指令を受けた時点からその時点以降の直近の電流ゼロ点までの時間が開極時間よりも短い場合には、その直近の電流ゼロ点では３相のバルブはいずれも開極状態とはならず、その直近の電流ゼロ点の次の電流ゼロ点で３相のうちいずれか１相のバルブが開極状態となる。そして、遮断指令を受けてから３相のうちいずれか１相のバルブが開極状態となるまでの時間の変動幅は、上記と同様、電流ゼロ点間隔である。
【００２４】
（３）電源切替の制御方法
上記のように、開極時間が電流ゼロ点間隔よりも短い機械式開閉器を用いると、開極動作時間が確定する。しかし、この開極動作時間は、切替指令の時点に依存し、電流ゼロ点間隔に相当する変動幅を有している。したがって、上記のような機械式の高速度３相遮断器を用いた電源切替装置によって電源を切り替える際において負荷に影響を与えないようにするには、この開極動作時間の変動を考慮した上で、切替時間が１０ｍｓ以下となるようにその高速度３相遮断器の開閉を制御しなければならない。
【００２５】
図６は、このための電源切替の制御方法を示すタイミング図であって、この図では、負荷に電力を供給する電源を２つの３相交流電源の間で切り替える場合が想定されている。また、電源切替装置における２つの機械式開閉器として共に高速度３相遮断器が使用され、各３相遮断器は３相交流の各相に対応する３つのバルブを含んでおり、それらの開極時間は１ｍｓであって、その３相交流の電流ゼロ点間隔よりも短いものとする。以下では、その３相交流の周波数は６０Ｈｚであって電流ゼロ点間隔は２．８ｍｓであるものとして、電源切替の制御方法を説明する。
【００２６】
電源切替装置は、切替指令を受け取ると、その内部の２つの開閉器のうち閉状態開閉器に直ちに遮断指令を出して開極動作を開始させる。この閉状態開閉器の開極動作時間は、前述のように、電流ゼロ点から開極時間（１ｍｓ）だけ前の時点（図５に示された時点Ｔ１）の直後に遮断指令（切替指令）を受け取った場合に最長となり、電流ゼロ点から開極時間だけ前の時点（時点Ｔ１）の直前に遮断指令（切替指令）を受け取った場合に最短となる。なお、３相交流電源を切り替える場合には、電源装置における各開閉器は３個のバルブを含むが、以下において、このような開閉器については、それら３個のバルブの全てが電気的に開いている状態（電気的に遮断されている状態）を開極状態または開状態といい、それら３個のバルブの全てが電気的に閉じている状態を閉極状態または閉状態というものとする。また、このような開閉器における開極動作時間とは、閉状態において遮断指令（切替指令）を受け取ってから３個のバルブの全てが電気的に開いた状態となるまでの時間をいうものとする。
【００２７】
開極動作時間が最長となる場合（以下「最長ケース」という）では、切替指令を受け取った時点以降の直近の電流ゼロ点（以下「切替指令後１つ目の電流ゼロ点」という）では閉状態開閉器における３台のバルブはいずれも閉極状態のままであり、その次の電流ゼロ点（以下「切替指令後２つ目の電流ゼロ点」という）で３相のうちいずれか１相のバルブ（以下「１相目のバルブ」という）が開極する（図５参照）。すなわち、切替指令を受け取ってから１＋２．８＝３．８［ｍｓ］後に１相目のバルブが開極する。これに対し、開極動作時間が最短となる場合（以下「最短ケース」という）では、切替指令後１つ目の電流ゼロ点で３相のうちいずれか１相のバルブ（１相目のバルブ）が開極する。すなわち、切替指令を受け取ってから１ｍｓ（開極時間）後に１相目のバルブが開極する。いずれのケースにおいても、１相目のバルブの開極後における電源電流は１相が欠相状態となって残りの２相の波形が歪み、１相目のバルブが開極してから約４ｍｓ後に残りの２相のバルブが開極する。このことは実験により検証されている。
【００２８】
図７はこの実験の結果を示している。この実験で使用された試験回路の構成は図８に示す通りであって、電源切替装置に使用される２個の機械式開閉器のうちの一方の開閉器（第１開閉器）を構成する３個のバルブは、この試験回路における３個の供試器Ｂt1，Ｂt3，Ｂt5に相当し、他方の開閉器（第２開閉器）を構成する３個のバルブは、この試験回路における他の３個の供試器Ｂt2，Ｂt4，Ｂt6に相当する。実際の電源切替装置ではこれら２つの開閉器に異なる電源が接続されるが、この試験回路では商用電源が第１および第２開閉器の双方に保護遮断器Ｂb1，Ｂb2および短絡変圧器Ｔr1，Ｔr2を介して接続されている。そして、この実験では、上記の２つの機械式開閉器として、開極時間が１．５ｍｓ以下であって定格操作電圧（１００Ｖ）における開極時間が１．０ｍｓの高速度３相遮断器が使用されている。図７（ａ）に示したＡ相、Ｂ相、Ｃ相の電圧は、図８に示した試験回路において電圧測定用分圧器Ｄｅによって測定されるＡ相、Ｂ相、Ｃ相の対地電圧Ｖ_A、Ｖ_B、Ｖ_Cにそれぞれ相当し、図７（ｂ）に示したＡ相、Ｂ相、Ｃ相の電流は、図８に示した試験回路において電流測定用変流器ＣＴによって測定されるＡ相、Ｂ相、Ｃ相の負荷電流にそれぞれ相当する。この実験における試験条件は下記の通りである。なお下記において、試験電圧は負荷側の線間電圧であり、試験電流は各負荷リアクトルＬを流れる電流（負荷電流）、操作電圧は制御装置の電圧である。
（１）試験電圧：６．６ｋＶ
（２）試験電流：６００Ａ
（３）試験周波数：６０Ｈｚ
（４）操作電圧：ＡＣ１００Ｖ
上記のように試験電圧（線間電圧）は６．６ｋＶで、試験電流は６００Ａであるので、各相の対地電圧は６．６／３^1/2＝３．８ｋＶであり、負荷リアクトル容量は（各相の対地電圧）×（各相の試験電流）×３＝（６．６／３^1/2）×６００×３＝６８５９ｋＶＡである。以上の試験条件の下、図７（ｂ）に示すように、“切替指令が出されると、Ｂ相の電流が遮断されてから３．８ｍｓ後にＡ相およびＣ相の電流が遮断される”という結果が得られている。これは、“遮断指令を受け取った開閉器では１相目のバルブが開極してから約４ｍｓ後に残りの２相のバルブが開極する”ことを示している。
【００２９】
上記のようにして、最長ケースでは切替指令を受けてから３．８＋４＝７．８［ｍｓ］後に閉状態開閉器の開極動作が完了し、最短ケースでは切替指令を受けてから１＋４＝５［ｍｓ］後に閉状態開閉器の開極動作が完了する。最短ケースと最長ケースとを比較すると、開極動作時間（切替指令を受け取ってから閉状態開閉器における３相のバルブの全てが開極状態となるまでの時間）は、２．８［ｍｓ］すなわち電流ゼロ点間隔だけ異なる。このように開極動作時間が変動しても電源切替によって負荷に影響が及ばないようにするには、図６に示されているように、最短ケースにおいて閉状態開閉器の開極動作が完了する時点Ｔｓから、許容される切替時間の最大値（以下「許容最大切替時間」という）である１０ｍｓだけ経過した時点Ｔｃまでに、他方の開閉器である開状態開閉器が閉極動作を完了するようにしなければならない。また、上記のように開極動作時間が変動しても電源オーバラップが生じないようにするには、最長ケースにおいて閉状態開閉器の開極動作が完了する時点ＴＬ以降に他方の開閉器である開状態開閉器が閉極動作を完了するようにしなければならない。したがって、開極動作時間に変動に拘わらず本発明の目的を達成するためには、最長ケースにおいて閉状態開閉器の開極動作が完了する時点ＴＬ以降であって、最短ケースにおいて閉状態開閉器の開極動作が完了する時点Ｔｓから許容最大切替時間（１０ｍｓ）だけ経過した時点Ｔｃよりも前に、開状態開閉器が閉極動作を完了するようにしなければならない。
【００３０】
そこで本制御方法では、切替指令を受け取ってから７．８ｍｓだけ経過した時点ＴＬと切替指令を受け取ってから５＋１０＝１５ｍｓだけ経過した時点Ｔｃとの間に開状態開閉器が閉極動作を完了するように、開状態開閉器に閉極動作を開始させる。具体的には、電源切替装置における開閉器の閉極動作時間が例えば１２ｍｓの場合には、切替指令を受けた時点と切替指令後３ｍｓ（＝１５−１２［ｍｓ］）経過した時点との間に、開状態開閉器に閉極動作を開始させればよい。また、閉極動作時間が例えば８ｍｓの場合には、切替指令を受けた時点と切替指令後７ｍｓ（＝１５−８［ｍｓ］）経過した時点との間に、開状態開閉器に閉極動作を開始させればよい。さらに、閉極動作時間が例えば６ｍｓの場合には、切替指令後１．８ｍｓ（＝７．８−６［ｍｓ］）経過した時点と切替指令後９ｍｓ（＝１５−６［ｍｓ］）経過した時点との間に、開状態開閉器に閉極動作を開始させればよい。なお、開状態開閉器の閉極動作を開始すべき期間を上記の期間よりも更に限定してもよい。このような限定により、切替時間を短縮して負荷への影響をより確実に抑え、電源オーバラップをより確実に回避することが可能となる。
【００３１】
＜実施形態＞
以下、本発明の各実施形態を添付図面を参照しつつ説明する。なお、以下では、両電源１０１，１０２は、周波数が６０Ｈｚの３相交流電源であるものとする。
【００３２】
＜１．第１の実施形態＞
図１は、本発明の第１の実施形態に係る電源切替装置の構成を示す図である。この電源切替装置１００は、負荷１２０に電力を供給する電源（電力供給源）を外部から与えられる切替信号Ｓswに応じて２つの３相交流電源の間で切り替える装置であって、図１に示した例では、コジェネレーション等の自家用発電設備１０１と商用電源１０２との間で電力供給源を切り替える。図１に示すように、この電源切替装置１００は、２つの機械式開閉器すなわち第１の開閉器１０および第２の開閉器２０と、制御装置１１０とを備えている。
【００３３】
第１および第２の開閉器１０，２０は、前述の高速度３相遮断器であって、共に、開極時間は１ｍｓ、閉極動作時間は１０±２［ｍｓ］である。第１の開閉器１０は、３相交流の各相にそれぞれが対応する３個の真空バルブ１１，１２，１３を有しており、これらは電磁反発力によって開極する。第２の開閉器２０も、同様の構成であって、電磁反発力によって開極する３個の真空バルブ２１，２２，２３を有している。
【００３４】
制御装置１１０には、切替指令を示す切替信号Ｓswが電源切替装置１００の外部（例えば外部の切替スイッチ）から供給される。制御装置１１０は、その切替信号Ｓswに基づき、第１の開閉器１０に第１の開閉制御信号Ｓc1を、第２の開閉器２０に第２の開閉制御信号Ｓc2を、それぞれ供給する。第１および第２の開閉制御信号Ｓc1，Ｓc2は、遮断指令および開極指令を示す信号であって、第１の開閉制御信号Ｓc1は第１の開閉器１０の開閉（３個の真空バルブ１１〜１３の開閉）を指示し、第２の開閉制御信号Ｓc2は、第２の開閉器２０の開閉（３個の真空バルブ２１〜２３の開閉）を指示する。ここで第１の開閉器１０に開極動作を開始させる際にはＬレベルの第１の開閉制御信号Ｓc1が供給され、第１の開閉器１０が開状態（遮断状態）となった後も第１の開閉制御信号Ｓc1はＬレベルのままとなる。一方、第１の開閉器１０に閉極動作を開始させる際にはＨレベルの第１の開閉制御信号Ｓc1が供給され、第１の開閉器１０が閉状態となった後も第１の開閉制御信号Ｓc1はＨレベルのままとなる。このように第１の開閉制御信号Ｓc1の論理レベルは、第１の開閉器１０の開閉状態（開状態か閉状態か）に対応している。第２の開閉制御信号Ｓc2も同様に、第２の開閉器２０の開閉状態（開状態か閉状態か）に対応している。この電源切替装置１００は、切替信号Ｓswによって切替指令を受け取ると、第１および第２の開閉制御信号Ｓc1，Ｓc2で第１および第２の開閉器１０，２０の開閉を制御することにより、負荷１２０へ電力を供給する電源を切り換える。
【００３５】
次に、上記のように構成された第１の実施形態に係る電源切替装置１００の制御動作の詳細を図２を参照しつつ説明する。図２は、自家用発電設備１０１と商用電源１０２のいずれか一方から負荷１２０に電力が供給されている状態において、本実施形態の電源切替装置１００が切替指令を受けたときの制御装置１１０の動作を示している。
【００３６】
電源切替装置１００が切替指令を受け取ると、制御装置１１０は以下のように動作する。まず、第１および第２の開閉器１０，２０のいずれか一方または双方の開閉状態（開状態か閉状態か）を、第１および第２の開閉制御信号Ｓc1，Ｓc2の論理レベル（ＨレベルかＬレベルか）により判定する（ステップＳ１０，Ｓ３０）。
【００３７】
ステップＳ１０において第１の開閉器１０が開状態であると判定された場合、および、ステップＳ３０において第２の開閉器２０が閉状態であると判定された場合には、第１の開閉器１０には閉極動作を、第２の開閉器２０には開極動作を開始させる（ステップ２０）。このときの開極動作および閉極動作の開始タイミングは次の通りである。
【００３８】
すなわち、切替指令を受け取ると、Ｌレベルの第２の開閉制御信号Ｓc2を第２の開閉器２０に供給することにより、第２の開閉器２０に直ちに開極動作を開始させる（ステップＳ２６）。これにより、図６に示したように、最長で７．８ｍｓ後、最短で５ｍｓ後に、第２の開閉器２０の開極動作が完了する。一方、第１の開閉器１０に対しては、切替指令を受け取るとタイマーをスタートさせて所定時間Ｔｗだけ待機した後に、Ｈレベルの第１の開閉制御信号Ｓc1を供給することにより閉極動作を開始させる（ステップＳ２２，Ｓ２３）。ここで、待機する所定時間（以下「待機時間」という）Ｔｗを適切に設定することにより、図６に示したように、最長ケースにおいて第２の開閉器２０（閉状態開閉器）の開極動作が完了する時点ＴＬ以降であって、最短ケースにおいて第２の開閉器２０の開極動作が完了する時点Ｔｓから許容最大切替時間（１０ｍｓ）だけ経過した時点Ｔｃよりも前に、第１の開閉器１０（開状態開閉器）が閉極動作を完了するようにしている。すなわち、本実施形態では両電源１０１，１０２の周波数は６０Ｈｚであり、第１および第２の開閉器１０，２０の開極時間は１ｍｓであるので、切替指令後７．８ｍｓ経過した時点ＴＬと切替指令後１５ｍｓ経過した時点Ｔｃとの間に開状態開閉器が閉極動作を完了するように、開状態開閉器に閉極動作を開始させるべく上記の待機時間Ｔｗを設定している。
【００３９】
具体的には、第１および第２の開閉器１０，２０の閉極動作時間を１０±２ｍｓであることを考慮し、１〜３ｍｓの範囲から選択された適切な値を待機時間Ｔｗとして設定している。例えば、この待機時間Ｔｗを１ｍｓと設定した場合には、切替指令を受け取ってから最短で１＋（１０−２）＝９［ｍｓ］後、最長で１＋（１０＋２）＝１３［ｍｓ］後に、第１の開閉器１０の閉極動作が完了する。また、この待機時間Ｔｗを３ｍｓと設定した場合には、切替指令を受け取ってから最短で３＋（１０−２）＝１１［ｍｓ］後、最長で３＋（１０＋２）＝１５［ｍｓ］後に、第１の開閉器１０の閉極動作が完了する。
【００４０】
一方、ステップＳ１０において第１の開閉器１０が開状態ではないと判定された場合、および、ステップＳ３０において第２の開閉器２０が閉状態ではないと判定された場合には、第１の開閉器１０は閉状態にあり、第２の開閉器２０は開状態にあるので、第１の開閉器１０には開極動作を、第２の開閉器２０には閉極動作を開始させる（ステップＳ４０）。このときの開極動作および閉極動作の開始タイミングは、第１の開閉器１０と第２の開閉器２０とを入れ替えれば前述のステップＳ２０の場合と同様である。すなわち、切替指令を受け取ると、閉状態にある第１の開閉器１０に直ちに開極動作を開始させる（ステップＳ４２）。一方、開状態にある第２の開閉器２０に対しては、切替指令を受け取るとタイマーをスタートさせて、１ｍｓ〜３ｍｓの範囲から選択された適切な所定時間Ｔｗだけ待機した後に、閉極動作を開始させる（ステップＳ４６，Ｓ４７）。
【００４１】
以上のように本実施形態では、開極時間が電源の電流ゼロ点間隔よりも短い開閉器が使用されているため、開極動作時間の変動幅は電流ゼロ点間隔（２．８ｍｓ）である。そして、切替指令を受け取ると、第１および第２の開閉器１０，２０のうち閉状態開閉器は直ちに開極動作を開始し、開状態開閉器は、切替指令を受け取ってから１〜３ｍｓの間の適切な待機時間Ｔｗだけ経過した時点で閉極動作を開始する。その結果、切替指令後７．８ｍｓ経過した時点ＴＬと切替指令後１５ｍｓ経過した時点Ｔｃとの間に開状態開閉器が閉極動作を完了する。これは、最長ケースにおいて閉状態開閉器が開極動作を完了する後であって、最短ケースにおいて閉状態開閉器が開極動作を完了する時点から許容最大切替時間（１０ｍｓ）だけ経過する前までに、開状態開閉器の閉極動作が完了することを意味する。したがって、本実施形態によれば、電源オーバラップが回避され、電源切替によって負荷が影響されることもない。
【００４２】
＜２．第２の実施形態＞
図９は、本発明の第２の実施形態に係る電源切替装置の構成を示す図である。この電源切替装置２００は、第１の実施形態と同様、負荷１２０に電力を供給する電源（電力供給源）を、外部から与えられる切替信号Ｓswに応じて、２つの３相交流電源である自家用発電設備１０１と商用電源１０２との間で切り替える装置である。この電源切替装置２００の構成要素のうち第１の実施形態に係る電源装置（図１）おける構成要素と同一のものについては同一の符号を付して説明を省略する。ただし、本実施形態における第１および第２の開閉器１０，２０の閉極動作時間は、１０ｍｓ以下であるものとする。以下、第１の実施形態との相違点を中心に第２の実施形態について説明する。
【００４３】
本実施形態の電源切替装置２００は、第１および第２の開閉器１０，２０の開極動作の完了を電圧低下に基づいて検出するための電圧検知器３０を備えており、電圧検知器３０は、第１および第２の開閉器１０，２０のいずれかが開極動作を完了したか否かを示す検出信号Ｓｄを出力する。本実施形態における制御装置２１０は、第１の実施形態とは異なり、切替信号Ｓswとともに電圧検知器３０からの検出信号Ｓｄに基づいて第１および第２の開閉制御信号Ｓc1，Ｓc2を生成し、これらを第１および第２の開閉器１０，２０にそれぞれ供給する。
【００４４】
次に、上記のように構成された第２の実施形態に係る電源切替装置の制御動作の詳細を図１０を参照しつつ説明する。図１０は、自家用発電設備１０１と商用電源１０２のいずれか一方から負荷１２０に電力が供給されている状態において、本実施形態の電源切替装置２００が切替指令を受けたときの制御装置２１０の動作を示している。図１０におけるステップのうち図２におけるステップと同一のものには同一の符号を付して説明を省略する。以下では、本実施形態における制御装置２１０の動作のうち第１の実施形態における制御装置１１０の動作と相違する部分を中心に説明する。
【００４５】
ステップＳ５０は、第１の開閉器１０が開状態にあって第２の開閉器２０が閉状態にある場合において切替指令を受けたときの制御装置２１０の動作を示している。この場合、切替指令を受け取ると、Ｌレベルの第２の開閉制御信号Ｓc2を第２の開閉器２０に供給することにより、第２の開閉器２０に直ちに開極動作を開始させる（ステップＳ５６）。一方、第１の開閉器１０に対しては、電圧検知器３０からの検出信号Ｓｄに基づき第２の開閉器２０の開極動作の完了が検出されるまで待機した後に、Ｈレベルの第１の開閉制御信号Ｓc1を供給することにより閉極動作を開始させる（ステップＳ５２，Ｓ５３）。本実施形態における第１の開閉器１０の閉極動作時間は１０ｍｓ以下であるため、第１の開閉器１０は、第２の開閉器２０の開極動作が完了してから最大許容切替時間（１０ｍｓ）が経過する前に閉極動作を完了する。
【００４６】
ステップＳ６０は、第１の開閉器１０が閉状態にあって第２の開閉器２０が開状態にある場合において切替指令を受けたときの制御装置２１０の動作を示している。この場合の制御装置２１０の動作は、第１の開閉器１０と第２の開閉器２０とを入れ替えれば前述のステップＳ５０の場合と同様である。すなわち、切替指令を受け取ると、第１の開閉器１０に直ちに開極動作を開始させる（ステップＳ７２）。一方、第２の開閉器２０に対しては、電圧検知器３０からの検出信号Ｓｄに基づき第１の開閉器１０の開極動作の完了が検知されるまで待機した後に閉極動作を開始させる（ステップＳ７６，Ｓ７７）。したがって、第２の開閉器２０の閉極動作時間は１０ｍｓ以下であるため、この場合も、第２の開閉器２０は、第１の開閉器１０の開極動作が完了してから最大許容切替時間（１０ｍｓ）が経過する前に閉極動作を完了する。
【００４７】
以上のようにして本実施形態では、切替指令を受け取ると、第１および第２の開閉器１０，２０のうち閉状態開閉器は直ちに開極動作を開始し、開状態開閉器は、閉状態開閉器の開極動作の完了を電圧検知器３０で検出した時点で閉極動作を開始する。そして本実施形態における第１および第２の開閉器の閉極動作時間は１０ｍｓ以下であるため、閉状態開閉器の開極動作が実際に完了した時点とその時点から最大許容切替時間（１０ｍｓ）だけ経過した時点との間に開状態開閉器が閉極動作を完了する。したがって、本実施形態によれば、電源オーバラップが回避され、電源切替によって負荷が影響されることもない。
【００４８】
なお、本実施形態では、電源切替に際に、閉状態開閉器の開極動作の完了が検出されてから開状態開閉器の閉極動作が開始されるため、開極動作時間が確定する必要はない。したがって、第１の実施形態とは異なり、第１および第２の開閉器１０，２０の開極時間は電流ゼロ点間隔よりも長くてもよい。
【００４９】
＜３．変形例＞
上記の第１および第２の実施形態では、切り換えるべき電源の周波数は６０Ｈｚであるとしているが、電源の周波数が５０Ｈｚの場合であっても、上記の第１および第２の実施形態と同様の構成の電源切替装置が実現可能であり、同様の効果が得られる。すなわち、電源の周波数が５０Ｈｚの場合であっても、第１の実施形態と同様、電源の切替の際に、最長ケースにおいて閉状態開閉器が開極動作を完了する後であって、最短ケースにおいて閉状態開閉器が開極動作を完了する時点から許容最大切替時間（１０ｍｓ）だけ経過する前までに、開状態開閉器の閉極動作を完了させるような構成が実現可能である。また、電源の周波数が５０Ｈｚの場合であっても、第２の実施形態と同様、電源の切替の際に、閉状態開閉器の開極動作の完了を検出した後であって、その完了の検出時点から最大許容切替時間（１０ｍｓ）だけ経過する前までに、開状態開閉器の閉極動作を完了させるような構成が実現可能である。
【００５０】
また、上記の第１および第２の実施形態では、負荷１２０の種類に拘わらず電源切替が負荷１２０に影響を及ぼさないようにするために最大許容切替時間を１０ｍｓとしているが、負荷１２０の種類が限定されている場合には、そのような負荷１２０が電源切替によって影響されないような最大許容切替時間として１０ｍｓ以上の値を設定してもよい。
【図面の簡単な説明】
【図１】本発明の第１の実施形態に係る電源切替装置の構成を示すブロック図。
【図２】第１の実施形態に係る電源切替装置が切替指令を受けたときの制御装置の動作を示すフローチャート。
【図３】各種負荷機器の瞬時電圧低下の影響例を示す図。
【図４】３相交流電源における電流ゼロ点間隔を示す図。
【図５】開極時間が電源の電流ゼロ点間隔よりも短い機械式開閉器の開極動作を説明するための図。
【図６】第１の実施形態における電源切替の制御方法を説明するためのタイミング図。
【図７】第１の実施形態において使用される開閉器である機械式の高速度３相遮断器によって３相交流電源を遮断したときの実験結果である電圧および電流の変化を示す図。
【図８】図７に示す実験結果を得るために使用した試験回路の構成を示す回路図。
【図９】本発明の第２の実施形態に係る電源切替装置の構成を示すブロック図。
【図１０】第２の実施形態に係る電源切替装置が切替指令を受けたときの制御装置の動作を示すフローチャート。
【図１１】電源切替装置の使用例を示す図。
【図１２】従来の電源切替装置の概略構成を示すブロック図。
【符号の説明】
１０ …第１の開閉器（機械式の高速度３相遮断器）
２０ …第２の開閉器（機械式の高速度３相遮断器）
３０ …電圧検知器
１１〜１３ …真空バルブ
２１〜２３ …真空バルブ
１００…電源切替装置
１０１…自家用発電設備
１０２…商用電源
１１０…制御装置
１２０…負荷
２００…電源切替装置
２１０…制御装置
Ｓsw …切替信号
Ｓc1 …第１の開閉制御信号
Ｓc2 …第２の開閉制御信号[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power supply switching device that switches an AC power supply that supplies power to a load between two power supplies, for example, a power supply switching device that switches a power supply that supplies power to a load between a commercial power supply and a private power generation facility. .
[0002]
[Prior art]
In order to supply electric power to a load from a private power generation facility in the daytime and from a commercial power supply at night, as shown in FIG. 11, in a consumer having a private power generation facility such as cogeneration (hereinafter referred to as “in-house consumer”), 2. Description of the Related Art A power supply switching device that switches a power source that supplies power to a load (hereinafter referred to as “power supply source”) between a private power generation facility and a commercial power source is used. This power supply switching device provides a state where two power supplies are connected to the load at the same time without stopping the supply of power to the load, that is, an overlap between the two power supplies (hereinafter referred to as “power overlap”). It is required to switch the power supply source without causing it.
[0003]
FIG. 12 is a block diagram showing a schematic configuration of a conventional power supply switching device that switches a power supply source between two power supplies without causing a stop of power supply to a load or power supply overlap as described above. The power supply switching device 6 switches the power supply for supplying power to the load 7 between the first power supply 1 and the second power supply 2, and includes a first opening / closing part 61 and a second opening / closing part 62. These two opening / closing sections and a control device 64 are provided. One end of the first opening / closing part 61 is connected to the first power source 1, one end of the second opening / closing part 62 is connected to the second power source 2, and the other ends of the first and second opening / closing parts 61, 62 are connected to each other. They are connected to each other and to the load 7. The control device 64 includes the first and second open / close sections 61, 2 to switch the power supply source between the first and second power sources 1 and 2 without causing the power supply to the load to be stopped and the power source overlap. 62 is opened and closed reciprocally.
[0004]
Generally, the power supply switching device is classified into a semiconductor type, a mechanical type, and a hybrid type according to the type of the switch. In the semiconductor type, the opening / closing part is constituted by a semiconductor switch such as a thyristor, in the mechanical type, the opening / closing part is constituted by a mechanical switch, and in the hybrid type, the opening / closing part is constituted by a combination of the semiconductor switch and the mechanical switch. . By the way, if the power supply source is switched while avoiding the power supply overlap, the load is instantaneously disconnected from any power supply (hereinafter referred to as “instantaneous interruption state”). If the period of this momentary interruption state is long, the drop in the supply voltage to the load exceeds the allowable range and affects the load. In semiconductor-type or hybrid-type power switching devices, the period of instantaneous interruption (hereinafter referred to as “switching time”) at the time of power switching is on the order of microseconds, and therefore the load is not normally affected by power switching. . However, since the semiconductor switch has a large resistance when turned on, the semiconductor type or hybrid type power supply switching device is inferior to the mechanical power supply switching device in terms of efficiency. On the other hand, the mechanical power supply switching device is advantageous in terms of efficiency, but as described below, the switching time, which is a momentary interruption state at the time of power switching, becomes longer (for example, about 20 ms). Have a problem.
[0005]
[Problems to be solved by the invention]
In a mechanical switch, if an interruption command is received when an alternating current is flowing in a closed state, the opening state is reached when the alternating current becomes zero (hereinafter referred to as “zero current point”). In a conventional general mechanical switch, the time (called “opening time”) from when a breaking command is received in a closed state to when the contact is mechanically separated (called “opening time”) is long (usually 50 ms). As described above, that is, 3 cycles or more in the 60 Hz power source), the current zero point that is in the open state cannot be specified. By the way, in order to avoid power overlap at the time of power switching, a switch that is in a closed state (hereinafter referred to as “closed state switch”) of two switches in a mechanical power switching device is opened. After that, the other switch that has been in the open state (hereinafter referred to as “open state switch”) must be in the closed state. Therefore, when a conventional general mechanical switch is used in the power supply switching device, it is necessary to lengthen the time from when the switch command is received until the open state switch starts the closing operation. As a result, the period (switching time) of the instantaneous interruption state at the time of power supply switching becomes longer (for example, 20 ms), and the load is affected by power supply switching.
[0006]
SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a mechanical power supply switching apparatus capable of switching an AC power supply while avoiding power supply overlap and without causing a long switching time that affects the load. And
[0007]
[Means for Solving the Problems and Effects of the Invention]
A first aspect of the present invention is a power source switching device that switches between an AC power source that supplies power to a load between a first power source and a second power source according to a switching command.
Inserted between the first power source and the load, and in a closed state, the opening is greater than the current zero point interval, which is the time interval of the current zero point at which the current flowing from the first power source to the load becomes zero. A mechanical first switch for a short time;
It is inserted between the second power source and the load, and is opened more than the current zero point interval, which is the time interval of the current zero point at which the current flowing from the second power source to the load becomes zero in the closed state. A mechanical second switch for a short time;
Control means for receiving the switch command and reciprocally opening and closing the first and second switches according to the switch command so that simultaneous connection to the load of the first and second power supplies is avoided. When,
With
When the control means receives the switching command, the control means immediately causes the closed state switch in the closed state of the first and second switches to start the opening operation, and the first and second opening / closing operations. The open state switch in the open state of the open circuit is connected to the open state switch after the open state of the closed state switch has been completed and before a predetermined switching time has elapsed since the completion of the open state operation. The closing operation is started so that the closing operation of the state switch is completed.
[0008]
According to the first aspect of the invention, the power supply source is switched between the two AC power sources in accordance with the switching command by the mechanical power source switching device, and the open state switch is opened and closed during the power source switching. The closing operation is completed after the opening operation of the device is completed and before a predetermined switching time has elapsed since the completion of the opening operation. By the way, as will be described later, it is known that the load is not affected regardless of the type of the load when the switching time (period of the instantaneous interruption state) is 10 ms or less in the power supply switching. In addition, since the opening times of the first and second switches in the first invention are shorter than the current zero point interval, the time from when the switching command is received until the completion of the opening operation (opening operation) The fluctuation range of (time) is a current zero point interval, and the current zero point interval is about 2.8 ms when a three-phase AC power source of 60 Hz, for example, is assumed as the first and second power sources. Therefore, even if a short switching time that does not affect the load is set, regardless of fluctuations in the opening operation time, after the opening operation of the closed state switch is completed, the opening operation is completed. It is possible to cause the open state switch to start the closing operation so that the closing operation of the open state switch is completed before the switching time elapses. Therefore, in the first aspect of the present invention, by appropriately setting the switching time according to the type of load (when the type of load is not limited, set to 10 ms or less), by avoiding power supply overlap, it is possible to perform power switching. The impact on the load can be suppressed.
[0009]
According to a second invention, in the first invention,
The shortest opening operation time is defined as the minimum value of the opening operation time that is the time interval from the reception time point when the control means receives the switching command to the completion time of the opening operation, and the opening operation time Assuming that the longest opening operation time is defined as the maximum value, the control means, after the longest opening operation time has elapsed since the reception time of the switching command, and from the reception time of the switching command, The closing state operation is started by the open state switch so that the closing operation of the open state switch is completed before the sum of the shortest opening time and the switching time elapses. And
[0010]
According to the second aspect of the invention, after the longest opening operation time elapses from the time when the switching command is received, the sum of the shortest opening operation time and the switching time elapses after the switching command is received. Before, the closing operation of the open state switch is completed. Therefore, by appropriately setting the switching time according to the type of load (when the type of load is not limited, it is set to 10 ms or less), while avoiding power supply overlap regardless of fluctuations in the opening operation time. The influence on the load due to the power switching can be suppressed.
[0011]
According to a third invention, in the first invention,
Assuming that the longest opening operation time is defined as the maximum value of the opening operation time that is the time interval from the reception time point when the control means receives the switching command to the completion time point of the opening operation, the control means , The closing operation of the open state switch during a period immediately after the longest opening operation time has elapsed from the time of receipt of the switching command and corresponding to the difference between the switching time and the current zero point interval. The closing operation is started by the open state switch so as to complete.
[0012]
According to the third aspect of the invention, the period immediately after the longest opening operation time has elapsed from the time when the switching command is received, and the period corresponding to the difference between the switching time and the current zero point interval. The closing operation of the open state switch is completed. In the third aspect of the invention, the opening time of the first and second switches is shorter than the current zero point interval, so the fluctuation range of the opening operation time is the current zero point interval. Therefore, by appropriately setting the switching time according to the type of load (set to 10 ms or less when the type of load is not limited), while avoiding power supply overlap regardless of fluctuations in the opening operation time, The influence on the load due to power switching can be suppressed.
[0013]
According to a fourth invention, in any one of the first to third inventions,
The first and second power sources are three-phase AC power sources having a frequency of 60 Hz,
The control means receives the switching command. Et al 6 . After the elapse of the time obtained by adding the opening time of the closed state switch to 8 milliseconds, has the switch command been received? Et al 4 . Before the elapse of the time obtained by adding the opening time of the closed state switch and the switching time to 0 milliseconds, the closing operation is performed in the open state so that the closing operation of the open state switch is completed. The switch is started.
[0014]
In the fourth aspect, since the first and second power supplies are three-phase AC power supplies having a frequency of 60 Hz, the current zero point interval is about 2.8 ms. Also, if the three-phase AC power supply is shut off in a high-speed three-phase circuit breaker that is a mechanical switch, the remaining two-phase valves are opened after about 4 ms after the first-phase valve opens. This is verified by the experimental results described later. Therefore, the opening operation time is “opening time + 2.8 + 4” [ms] at the longest and “opening time + 4” [ms] at the shortest. Correspondingly, in the fourth aspect of the invention, is a switching command received? Et al 6 . After switching time is added to 8 milliseconds, is the switching command received? Et al 4 Before the elapse of the time obtained by adding the opening time and the switching time to milliseconds, the closing operation of the open state switch is completed. Therefore, according to the fourth aspect of the invention, by appropriately setting the switching time according to the type of load (set to 10 ms or less when the type of load is not limited), regardless of fluctuations in the opening operation time. Thus, it is possible to suppress the influence on the load due to the power supply switching while avoiding the power supply overlap.
[0015]
A fifth aspect of the invention is a power source switching device that switches between an AC power source that supplies power to a load between a first power source and a second power source according to a switching command,
A mechanical first switch inserted between the first power source and the load;
A mechanical second switch inserted between the second power source and the load;
Control means for receiving the switch command and reciprocally opening and closing the first and second switches according to the switch command so that simultaneous connection to the load of the first and second power supplies is avoided. When,
Detecting means for detecting completion of the opening operation when the closed state switch in the closed state among the first and second switches starts the opening operation;
With
The closing operation time of the first and second switches is shorter than a predetermined switching time,
Upon receipt of the switching command, the control means immediately causes the closed state switch of the first and second switches to start the opening operation, and the completion of the opening operation is detected by the detecting means. At the time, the closing operation of the open state switch in the open state among the first and second switches is started.
[0016]
According to the fifth aspect of the invention, the power supply source is switched between the two AC power sources according to the switching command by the mechanical power source switching device, and the open state switch is opened and closed when the power source is switched. When the completion of the opening operation of the device is detected by the detecting means, the closing operation is started. And the closing operation time of the 1st and 2nd switch in the said 5th invention is shorter than the predetermined switching time. Thus, in the fifth aspect of the invention, a switch having a switching operation time appropriately set according to the type of load (set to 10 ms or less when the type of load is not limited) and set according to the setting. By using this, it is possible to suppress the influence on the load due to the power supply switching while avoiding the power supply overlap regardless of the fluctuation of the opening operation time.
[0017]
According to a sixth invention, in any one of the first to fifth inventions,
The switching time is 10 milliseconds or less.
[0018]
As will be described later, it is known that the load is not affected regardless of the type of load if the switching time (period of instantaneous interruption state) is 10 ms or less in power supply switching. Therefore, according to the fifth aspect of the present invention, it is possible to suppress the influence on the load due to the power source switching regardless of the type of the load while avoiding the power source overlap.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
<Basic study>
First, a basic study for realizing a power supply switching apparatus according to an embodiment of the present invention will be described.
[0020]
(1) Switching time
The paper “Voluntary Voltage Drop Countermeasures” published by the Special Committee on Instantaneous Voltage Drops was published in “Voluntary Research on Electricity Collaborative” Vol. 46, No. 3 issued on July 18, 1990 by the Electric Joint Research Association (corporate association). Here, FIG. 3 showing an example of the influence of the instantaneous voltage drop of various load devices is disclosed. According to FIG. 3, it can be seen that for any load device, if the duration of the voltage drop is 10 ms (0.01 seconds) or less, the voltage drop does not affect the load regardless of the degree of the voltage drop. Therefore, if the period of instantaneous interruption at the time of power switching by the power switching device, that is, the switching time is 10 ms or less, the power switching does not affect the load.
[0021]
(2) Opening time and opening operation time
As described above, in the conventional general mechanical switch, since the opening time is long (usually 50 ms or more), the circuit breaker is opened (electrically closed) after receiving a cutoff command in the closing state. The opening operation time, which is the time to become, was not determined. However, in recent years, an electromagnetic repulsion device has been added to each of the three three-phase vacuum valves, and a three-phase collective AC circuit breaker with a very short opening time has been developed. Such a high-speed three-phase circuit breaker is disclosed in, for example, Japanese Patent Application Laid-Open No. 9-180600, and the opening time is about 1 ms, which is significantly shortened compared to the prior art. For example, in the case of 60 Hz three-phase alternating current, as shown in FIG. 4, the interval of one cycle is 1 s / 60 Hz = 0.166 ... [s], that is, about 16.7 ms, and the current zero point interval is 1 s / 60 Hz. / 3 phase / 2 = 0.00277 ... [s], that is, about 2.8 ms. Therefore, the opening time of the high-speed three-phase circuit breaker is sufficiently shorter than the current zero point interval. In this way, in a switch (breaker) in which the opening time is shorter than the current zero point interval, the opening operation time is determined unlike the conventional general mechanical switch.
[0022]
In other words, in a switch whose opening time is shorter than the current zero point interval, as shown in FIG. 5, the time from the time when the interruption command is received to the nearest current zero point after that time is longer than the opening time. In the case (when a cut-off command is received at time A), the contact is opened at the nearest current zero point C01. However, in FIG. 5, the time point that is the opening time before the latest current zero point C01 is T1. In addition, when the time from the time when the cutoff command is received to the nearest current zero point after that time is shorter than the opening time (when the cutoff command is received at time B), the latest current zero point C01. In this case, the open state is not reached, but the open state is always obtained at the current zero point C02 next to the current zero point immediately after. Therefore, the opening operation time is determined when the time point of the cutoff command is determined. However, as can be seen from FIG. 5, the opening operation time varies depending on the temporal relationship between the time when the interruption command is received and the current zero point. It becomes the shortest when a command is received, and becomes the longest when a cutoff command is received immediately after time T1. The opening operation time is equal to the opening time at the shortest, and is the time corresponding to the sum of the opening time and the current zero point interval at the longest. Therefore, in a mechanical switch in which the opening time is shorter than the current zero point interval, the fluctuation range of the opening operation time is the current zero point interval.
[0023]
FIG. 5 shows the timing of opening operation for a mechanical switch (or one valve constituting a three-phase circuit breaker) for a single-phase AC power source. The same applies to the timing when any one-phase valve is opened after receiving a shut-off command in the three-phase circuit breaker. That is, when the time from the time when the shut-off command is received to the nearest current zero point after that time is longer than the opening time, the valve of any one of the three phases at the nearest current zero point Opened state. On the other hand, when the time from the time when the shut-off command is received to the nearest current zero point after that time is shorter than the opening time, all the three-phase valves are in the open state at the nearest current zero point. The valve of any one of the three phases is opened at the current zero point next to the nearest current zero point. And the fluctuation width of the time after receiving the interruption | blocking instruction | command until any one phase valve | bulb will be in an open state of a 3 phase is an electric current zero point space | interval similarly to the above.
[0024]
(3) Power supply switching control method
As described above, when using a mechanical switch whose opening time is shorter than the current zero point interval, the opening operation time is determined. However, the opening operation time depends on the time point of the switching command and has a fluctuation range corresponding to the current zero point interval. Therefore, in order not to affect the load when the power source is switched by the power source switching device using the mechanical high-speed three-phase circuit breaker as described above, the fluctuation of the opening operation time is taken into consideration. Therefore, the switching of the high-speed three-phase circuit breaker must be controlled so that the switching time is 10 ms or less.
[0025]
FIG. 6 is a timing diagram showing a power switching control method for this purpose. In this figure, it is assumed that the power source that supplies power to the load is switched between two three-phase AC power sources. In addition, a high-speed three-phase circuit breaker is used as two mechanical switches in the power switching device, and each three-phase circuit breaker includes three valves corresponding to each phase of a three-phase alternating current. The pole time is 1 ms, which is shorter than the current zero point interval of the three-phase alternating current. Below, the control method of power supply switching is demonstrated on the assumption that the frequency of the three-phase alternating current is 60 Hz and the current zero point interval is 2.8 ms.
[0026]
When the power supply switching device receives the switching command, it immediately issues a disconnection command to the closed state switch among the two switches inside the power switching device to start the opening operation. As described above, the opening operation time of this closed-state switch is the interruption command (switching command) immediately after the time (time T1 shown in FIG. 5) just before the opening time (1 ms) from the current zero point. Is the longest, and is the shortest when the cutoff command (switching command) is received immediately before the time point (time point T1) just before the opening time from the current zero point. In addition, when switching a three-phase alternating current power supply, each switch in a power supply device includes three valves. However, in the following, all of these three valves are electrically opened for such a switch. A state in which the three valves are electrically disconnected is referred to as an open state or an open state, and a state in which all three valves are electrically closed is referred to as a closed state or a closed state. Further, the opening operation time in such a switch means the time from when a shut-off command (switching command) is received in a closed state until all three valves are in an electrically open state. To do.
[0027]
When the opening operation time is the longest (hereinafter referred to as “longest case”), it is closed at the most recent current zero point after receiving the switching command (hereinafter referred to as the “first current zero point after switching command”). All three valves in the state switch remain closed, and any one of the three phases at the next current zero point (hereinafter referred to as the “second current zero point after switching command”). The valve (hereinafter referred to as “first phase valve”) is opened (see FIG. 5). That is, the valve of the first phase is opened 1 + 2.8 = 3.8 [ms] after receiving the switching command. On the other hand, when the opening operation time is the shortest (hereinafter referred to as the “shortest case”), one of the three-phase valves (the first-phase valve) at the first current zero point after the switching command. ) Is opened. That is, the valve of the first phase opens 1 ms (opening time) after receiving the switching command. In either case, the power supply current after the opening of the first phase valve is approximately 4 ms after the first phase valve is opened due to the distortion of the remaining two-phase waveforms due to the phase loss of the first phase. Later, the remaining two-phase valves are opened. This has been verified by experiments.
[0028]
FIG. 7 shows the results of this experiment. The configuration of the test circuit used in this experiment is as shown in FIG. 8, and constitutes one of the two mechanical switches used in the power supply switching device (first switch). The three valves correspond to the three test devices Bt1, Bt3, Bt5 in this test circuit, and the three valves constituting the other switch (second switch) are the other in this test circuit. This corresponds to three test devices Bt2, Bt4, and Bt6. In an actual power switching device, different power sources are connected to these two switches, but in this test circuit, the commercial power source is connected to both the first and second switches as protective circuit breakers Bb1, Bb2 and short-circuit transformers Tr1, Tr2. Connected through. In this experiment, a high-speed three-phase circuit breaker having an opening time of 1.5 ms or less and an opening time of 1.0 ms at the rated operating voltage (100 V) is used as the two mechanical switches. Has been. The voltages of the A phase, the B phase, and the C phase shown in FIG. 7A are the ground voltages V of the A phase, the B phase, and the C phase that are measured by the voltage measuring voltage divider De in the test circuit shown in FIG. _A , V _B , V _C 7A, the currents of the A phase, the B phase, and the C phase shown in FIG. 7B are respectively measured by the current measuring current transformer CT in the test circuit shown in FIG. It corresponds to the load current of phase C, respectively. The test conditions in this experiment are as follows. In the following, the test voltage is a line voltage on the load side, the test current is a current flowing through each load reactor L (load current), and the operation voltage is the voltage of the control device.
(1) Test voltage: 6.6 kV
(2) Test current: 600A
(3) Test frequency: 60Hz
(4) Operating voltage: AC100V
Since the test voltage (line voltage) is 6.6 kV and the test current is 600 A as described above, the ground voltage of each phase is 6.6 / 3. ^1/2 = 3.8 kV, and the load reactor capacity is (ground voltage of each phase) × (test current of each phase) × 3 = (6.6 / 3) ^1/2 ) × 600 × 3 = 6859 kVA. Under the above test conditions, as shown in FIG. 7B, “When a switching command is issued, the currents in the A phase and the C phase are cut off 3.8 ms after the B phase current is cut off.” The result is obtained. This indicates that “the switch that receives the shut-off command opens the remaining two-phase valves about 4 ms after the first-phase valve opens”.
[0029]
As described above, the opening operation of the closed state switch is completed 3.8 + 4 = 7.8 [ms] after receiving the switching command in the longest case, and 1 + 4 = 5 after receiving the switching command in the shortest case. After [ms], the opening operation of the closed state switch is completed. Comparing the shortest case with the longest case, the opening operation time (the time from when the switching command is received until all the three-phase valves in the closed state switch are opened) is 2.8 [ms]. That is, only the current zero point interval is different. In order to prevent the load from being affected by switching the power supply even if the opening operation time fluctuates in this way, as shown in FIG. 6, the opening operation of the closed state switch is completed in the shortest case. From the time point Ts to the time point Tc when 10 ms which is the maximum allowable switching time (hereinafter referred to as “allowable maximum switching time”) has elapsed, the open state switch as the other switch completes the closing operation. You have to do that. Further, in order to prevent power supply overlap even if the opening operation time fluctuates as described above, in the longest case, the other switch is used after the time TL when the opening operation of the closed state switch is completed. One open switch must complete the closing operation. Therefore, in order to achieve the object of the present invention regardless of fluctuations in the opening operation time, after the time TL when the opening operation of the closed state switch is completed in the longest case, the closed state switch is used in the shortest case. Before the time Tc when the maximum allowable switching time (10 ms) has elapsed from the time Ts at which the opening operation is completed, the open state switch must complete the closing operation.
[0030]
Therefore, in this control method, the open state switch completes the closing operation between the time TL when only 7.8 ms has elapsed after receiving the switching command and the time Tc when only 5 + 10 = 15 ms has elapsed since receiving the switching command. Thus, the open state switch is caused to start the closing operation. Specifically, when the closing operation time of the switch in the power supply switching device is 12 ms, for example, between the time when the switching command is received and the time when 3 ms (= 15-12 [ms]) has elapsed after the switching command. In addition, it is only necessary to start the closing operation of the open state switch. In addition, when the closing operation time is 8 ms, for example, the opening state switch is closed between the time when the switching command is received and the time when 7 ms (= 15−8 [ms]) has elapsed after the switching command. Can be started. Further, when the closing operation time is 6 ms, for example, 1.8 ms (= 7.8-6 [ms]) after the switching command and 9 ms (= 15-6 [ms]) after the switching command have elapsed. What is necessary is just to start closing operation | movement to an open state switch between time. In addition, you may further limit the period which should start closing operation | movement of an open state switch rather than said period. Such a limitation makes it possible to shorten the switching time, more reliably suppress the influence on the load, and more reliably avoid power supply overlap.
[0031]
<Embodiment>
Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In the following, it is assumed that both power sources 101 and 102 are three-phase AC power sources having a frequency of 60 Hz.
[0032]
<1. First Embodiment>
FIG. 1 is a diagram illustrating a configuration of a power supply switching device according to a first embodiment of the present invention. The power supply switching device 100 is a device that switches a power supply (power supply source) that supplies power to the load 120 between two three-phase AC power supplies according to a switching signal Ssw given from the outside, and is shown in FIG. In this example, the power supply source is switched between the private power generation facility 101 such as cogeneration and the commercial power source 102. As shown in FIG. 1, the power supply switching device 100 includes two mechanical switches, that is, a first switch 10 and a second switch 20, and a control device 110.
[0033]
The first and second switches 10 and 20 are the above-described high-speed three-phase circuit breakers, both of which have an opening time of 1 ms and a closing operation time of 10 ± 2 [ms]. The first switch 10 includes three vacuum valves 11, 12, and 13 that respectively correspond to three-phase alternating current phases, and these are opened by electromagnetic repulsion. The second switch 20 has the same configuration and includes three vacuum valves 21, 22, and 23 that are opened by electromagnetic repulsion.
[0034]
A switching signal Ssw indicating a switching command is supplied to the control device 110 from the outside of the power supply switching device 100 (for example, an external changeover switch). Based on the switching signal Ssw, the control device 110 supplies the first switch 10 with the first switch control signal Sc1 and the second switch 20 with the second switch control signal Sc2. The first and second opening / closing control signals Sc1 and Sc2 are signals indicating a cutoff command and an opening command, and the first opening / closing control signal Sc1 is used to open / close the first switch 10 (three vacuum valves 11). ˜13) and the second opening / closing control signal Sc2 instructs opening / closing of the second switch 20 (opening / closing of the three vacuum valves 21-23). Here, when the first switch 10 starts the opening operation, the L-level first switch control signal Sc1 is supplied, and even after the first switch 10 is opened (cut-off state). The first opening / closing control signal Sc1 remains at the L level. On the other hand, when the first switch 10 starts the closing operation, the first switch control signal Sc1 of H level is supplied, and the first switch 10 is opened even after the first switch 10 is closed. The control signal Sc1 remains at the H level. As described above, the logic level of the first switching control signal Sc1 corresponds to the switching state (open state or closed state) of the first switch 10. Similarly, the second switching control signal Sc2 corresponds to the open / closed state (open state or closed state) of the second switch 20. When the power supply switching device 100 receives the switching command by the switching signal Ssw, the power switching device 100 controls the opening and closing of the first and second switches 10 and 20 by the first and second switching control signals Sc1 and Sc2, thereby loading the load. The power source for supplying power to 120 is switched.
[0035]
Next, details of the control operation of the power supply switching apparatus 100 according to the first embodiment configured as described above will be described with reference to FIG. FIG. 2 shows the operation of the control device 110 when the power switching device 100 according to the present embodiment receives a switching command in a state where power is supplied to the load 120 from either the private power generation facility 101 or the commercial power source 102. Is shown.
[0036]
When the power supply switching device 100 receives the switching command, the control device 110 operates as follows. First, the switching state (open state or closed state) of one or both of the first and second switches 10 and 20 is determined based on the logical level (H level) of the first and second switching control signals Sc1 and Sc2. Or L level) (steps S10 and S30).
[0037]
If it is determined in step S10 that the first switch 10 is in the open state, and if it is determined in step S30 that the second switch 20 is in the closed state, the first switch 10 Is closed, and the second switch 20 is started to open (step 20). The start timing of the opening operation and closing operation at this time is as follows.
[0038]
That is, when the switching command is received, the second switch 20 is immediately started to open a contact by supplying the second switch 20 with the L-level second switching control signal Sc2 (step S26). As a result, as shown in FIG. 6, after a maximum of 7.8 ms and a minimum of 5 ms, 2 Open and close Vessel 2 The opening operation of 0 is completed. On the other hand, the first switch 10 receives a switching command, starts a timer, waits for a predetermined time Tw, and then supplies a first switching control signal Sc1 of H level to perform a closing operation. Start (steps S22, S23). Here, by appropriately setting a predetermined waiting time (hereinafter referred to as “waiting time”) Tw, as shown in FIG. 6, the second switch 20 (closed state switch) is opened in the longest case. After the time TL at which the operation is completed, and before the time Tc when the maximum switching time (10 ms) has elapsed from the time Ts at which the opening operation of the second switch 20 is completed in the shortest case, the first switch The switch 10 (open state switch) completes the closing operation. That is, in this embodiment, the frequency of both power supplies 101 and 102 is 60 Hz, and the opening time of the first and second switches 10 and 20 is 1 ms. The waiting time Tw is set so that the open state switch starts the closing operation so that the open state switch completes the closing operation between the time Tc when 15 ms elapses after the switching command.
[0039]
Specifically, considering that the closing operation time of the first and second switches 10 and 20 is 10 ± 2 ms, an appropriate value selected from the range of 1 to 3 ms is set as the waiting time Tw. is doing. For example, when this waiting time Tw is set to 1 ms, the first after 1+ (10−2) = 9 [ms] after receiving the switching command, and the first after 1+ (10 + 2) = 13 [ms] The closing operation of the first switch 10 is completed. In addition, when the waiting time Tw is set to 3 ms, after the switching command is received, 3+ (10−2) = 11 [ms] at the shortest and 3+ (10 + 2) = 15 [ms] at the longest The closing operation of the first switch 10 is completed.
[0040]
On the other hand, if it is determined in step S10 that the first switch 10 is not open, and if it is determined in step S30 that the second switch 20 is not closed, the first switch Since the switch 10 is in the closed state and the second switch 20 is in the open state, the first switch 10 starts the opening operation, and the second switch 20 starts the closing operation (step) S40). The start timing of the opening operation and the closing operation at this time is the same as that in step S20 described above if the first switch 10 and the second switch 20 are exchanged. That is, when the switching command is received, the first switch 10 in the closed state immediately starts the opening operation (step S42). On the other hand, for the second switch 20 in the open state, when a switching command is received, a timer is started, and after waiting for an appropriate predetermined time Tw selected from the range of 1 ms to 3 ms, the closing operation is performed. Is started (steps S46 and S47).
[0041]
As described above, in the present embodiment, since the switch whose opening time is shorter than the current zero point interval of the power supply is used, the fluctuation range of the opening operation time is the current zero point interval (2.8 ms). . When the switching command is received, the closed state switch of the first and second switches 10 and 20 immediately starts the opening operation, and the open state switch receives 1 to 3 ms after receiving the switching command. The closing operation is started when an appropriate waiting time Tw has passed. As a result, the open state switch completes the closing operation between the time TL when 7.8 ms elapses after the switching command and the time Tc when 15 ms elapses after the switching command. This is after the closed state switch completes the opening operation in the longest case and until the maximum allowable switching time (10 ms) elapses after the closed state switch completes the opening operation in the shortest case. This means that the closing operation of the open state switch is completed. Therefore, according to the present embodiment, power supply overlap is avoided and the load is not affected by power supply switching.
[0042]
<2. Second Embodiment>
FIG. 9 is a diagram showing a configuration of a power supply switching apparatus according to the second embodiment of the present invention. As in the first embodiment, the power supply switching device 200 is a personal power supply (power supply source) that supplies power to the load 120 in accordance with a switching signal Ssw given from the outside, which is two-phase AC power supply. It is a device that switches between the power generation facility 101 and the commercial power source 102. Among the components of the power supply switching device 200, the same components as those in the power supply device according to the first embodiment (FIG. 1) are denoted by the same reference numerals and description thereof is omitted. However, the closing operation time of the first and second switches 10 and 20 in this embodiment is 10 ms or less. Hereinafter, the second embodiment will be described with a focus on differences from the first embodiment.
[0043]
The power supply switching apparatus 200 of this embodiment includes a voltage detector 30 for detecting the completion of the opening operation of the first and second switches 10 and 20 based on the voltage drop. Outputs a detection signal Sd indicating whether one of the first and second switches 10 and 20 has completed the opening operation. Unlike the first embodiment, the control device 210 in the present embodiment generates the first and second opening / closing control signals Sc1 and Sc2 based on the detection signal Sd from the voltage detector 30 together with the switching signal Ssw, These are supplied to the first and second switches 10 and 20, respectively.
[0044]
Next, details of the control operation of the power supply switching apparatus according to the second embodiment configured as described above will be described with reference to FIG. FIG. 10 shows the operation of the control device 210 when the power switching device 200 of this embodiment receives a switching command in a state where power is supplied to the load 120 from either the private power generation facility 101 or the commercial power source 102. Is shown. Steps in FIG. 10 that are the same as those in FIG. 2 are given the same reference numerals, and descriptions thereof are omitted. Below, it demonstrates centering on the part which is different from the operation | movement of the control apparatus 110 in 1st Embodiment among the operation | movement of the control apparatus 210 in this embodiment.
[0045]
Step S50 shows the operation of the control device 210 when a switching command is received when the first switch 10 is in the open state and the second switch 20 is in the closed state. In this case, when the switching command is received, the second switch 20 is immediately started to open a contact by supplying the second switching control signal Sc2 of L level to the second switch 20 (step S56). . On the other hand, the first switch 10 waits until the completion of the opening operation of the second switch 20 is detected based on the detection signal Sd from the voltage detector 30, and then the first switch at the H level. The opening / closing control signal Sc1 is supplied to start the closing operation (steps S52 and S53). Since the closing operation time of the first switch 10 in the present embodiment is 10 ms or less, the first switch 10 has a maximum allowable switching time (after the opening operation of the second switch 20 is completed) The closing operation is completed before 10 ms).
[0046]
Step S60 shows the operation of the control device 210 when a switching command is received when the first switch 10 is in the closed state and the second switch 20 is in the open state. The operation of the control device 210 in this case is the same as that in step S50 described above if the first switch 10 and the second switch 20 are replaced. That is, when the switching command is received, the first switch 10 immediately starts the opening operation (step S72). On the other hand, for the second switch 20, the first switch is based on the detection signal Sd from the voltage detector 30. 1 After waiting until the completion of the zero opening operation is detected, the closing operation is started (steps S76 and S77). Therefore, since the closing operation time of the second switch 20 is 10 ms or less, the second switch 20 also performs the maximum allowable switching after the opening operation of the first switch 10 is completed. The closing operation is completed before the time (10 ms) elapses.
[0047]
As described above, in the present embodiment, when the switching command is received, the closed state switch of the first and second switches 10 and 20 immediately starts the opening operation, and the open state switch is in the closed state. When the voltage detector 30 detects the completion of the opening operation of the switch, the closing operation is started. Since the closing operation time of the first and second switches in this embodiment is 10 ms or less, the opening operation of the closed state switch is actually completed and the maximum allowable switching time (10 ms) from that point. The open state switch completes the closing operation between the point of time that has passed only. Therefore, according to the present embodiment, power supply overlap is avoided and the load is not affected by power supply switching.
[0048]
In the present embodiment, when the power supply is switched, since the closing operation of the open state switch is started after the completion of the opening operation of the closed state switch is detected, it is necessary to determine the opening operation time. There is no. Therefore, unlike the first embodiment, the opening time of the first and second switches 10 and 20 may be longer than the current zero point interval.
[0049]
<3. Modification>
In the first and second embodiments described above, the frequency of the power source to be switched is 60 Hz, but even if the frequency of the power source is 50 Hz, the same as in the first and second embodiments above The power switching device having the configuration can be realized, and the same effect can be obtained. That is, even when the frequency of the power supply is 50 Hz, as in the first embodiment, when the power supply is switched, the shortest case is after the closed state switch completes the opening operation in the longest case. In this case, it is possible to realize a configuration in which the closing operation of the open state switch is completed before the allowable maximum switching time (10 ms) elapses after the closed state switch completes the opening operation. Further, even when the frequency of the power source is 50 Hz, as in the second embodiment, after the completion of the opening operation of the closed state switch at the time of switching the power source, A configuration in which the closing operation of the open state switch is completed before the maximum allowable switching time (10 ms) elapses from the detection time point can be realized.
[0050]
In the first and second embodiments described above, the maximum allowable switching time is set to 10 ms so that the power switching does not affect the load 120 regardless of the type of the load 120. In such a case, a value of 10 ms or more may be set as the maximum allowable switching time such that the load 120 is not affected by the power source switching.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a power supply switching apparatus according to a first embodiment of the present invention.
FIG. 2 is a flowchart showing the operation of the control device when the power supply switching device according to the first embodiment receives a switching command;
FIG. 3 is a diagram showing an example of the influence of an instantaneous voltage drop of various load devices.
FIG. 4 is a diagram showing a current zero point interval in a three-phase AC power supply.
FIG. 5 is a diagram for explaining the opening operation of a mechanical switch in which the opening time is shorter than the current zero point interval of the power supply.
FIG. 6 is a timing chart for explaining a control method of power supply switching in the first embodiment.
FIG. 7 is a diagram showing changes in voltage and current, which are experimental results when a three-phase AC power supply is interrupted by a mechanical high-speed three-phase circuit breaker that is a switch used in the first embodiment.
8 is a circuit diagram showing a configuration of a test circuit used for obtaining the experimental result shown in FIG. 7. FIG.
FIG. 9 is a block diagram showing a configuration of a power switching device according to a second embodiment of the present invention.
FIG. 10 is a flowchart showing the operation of the control device when the power switching device according to the second embodiment receives a switching command;
FIG. 11 is a diagram illustrating a usage example of the power supply switching device.
FIG. 12 is a block diagram showing a schematic configuration of a conventional power supply switching device.
[Explanation of symbols]
10 ... 1st switch (mechanical high-speed 3-phase circuit breaker)
20 ... Second switch (mechanical high-speed three-phase circuit breaker)
30 ... Voltage detector
11-13 ... Vacuum valve
21-23 ... Vacuum valve
100: Power switching device
101 ... Power generation equipment for private use
102: Commercial power supply
110 ... Control device
120 ... load
200 ... Power switching device
210 ... Control device
Ssw ... Switching signal
Sc1 ... first opening / closing control signal
Sc2 ... second opening / closing control signal

Claims

A power source switching device that switches between an AC power source that supplies power to a load between a first power source and a second power source according to a switching command,
Inserted between the first power source and the load, and in a closed state, the opening is greater than the current zero point interval, which is the time interval of the current zero point at which the current flowing from the first power source to the load becomes zero. A mechanical first switch for a short time;
It is inserted between the second power source and the load, and is opened more than the current zero point interval, which is the time interval of the current zero point at which the current flowing from the second power source to the load becomes zero in the closed state. A mechanical second switch for a short time;
Control means for receiving the switch command and reciprocally opening and closing the first and second switches according to the switch command so that simultaneous connection to the load of the first and second power supplies is avoided. When,
With
When the control means receives the switching command, the control means immediately causes the closed state switch in the closed state of the first and second switches to start the opening operation, and the first and second opening / closing operations. The open state switch in the open state of the open circuit is connected to the open state switch after the open state of the closed state switch has been completed and before a predetermined switching time has elapsed since the completion of the open state operation. Start the closing operation so that the closing operation of the state switch is completed ,
The shortest opening operation time is defined as the minimum value of the opening operation time that is the time interval from the reception time point when the control means receives the switching command to the completion time of the opening operation, and the opening operation time Assuming that the longest opening operation time is defined as the maximum value, the control means, after the longest opening operation time has elapsed since the reception time of the switching command, and from the reception time of the switching command, The closing state operation is started by the open state switch so that the closing operation of the open state switch is completed before the sum of the shortest opening time and the switching time elapses. A power switching device.

A power source switching device that switches between an AC power source that supplies power to a load between a first power source and a second power source according to a switching command,
Inserted between the first power source and the load, and in a closed state, the opening is greater than the current zero point interval, which is the time interval of the current zero point at which the current flowing from the first power source to the load becomes zero. A mechanical first switch for a short time;
It is inserted between the second power source and the load, and is opened more than the current zero point interval, which is the time interval of the current zero point at which the current flowing from the second power source to the load becomes zero in the closed state. A mechanical second switch for a short time;
Control means for receiving the switch command and reciprocally opening and closing the first and second switches according to the switch command so that simultaneous connection to the load of the first and second power supplies is avoided. When,
With
When the control means receives the switching command, the control means immediately causes the closed state switch in the closed state of the first and second switches to start the opening operation, and the first and second opening / closing operations. The open state switch in the open state of the open circuit is connected to the open state switch after the open state of the closed state switch has been completed and before a predetermined switching time has elapsed since the completion of the open state operation. Start the closing operation so that the closing operation of the state switch is completed ,
Assuming that the longest opening operation time is defined as the maximum value of the opening operation time that is the time interval from the reception time point when the control means receives the switching command to the completion time point of the opening operation, the control means , The closing operation of the open state switch during a period immediately after the longest opening operation time has elapsed from the time of receipt of the switching command and corresponding to the difference between the switching time and the current zero point interval. The power switching device is characterized by causing the open state switch to start the closing operation so as to be completed .

A power source switching device that switches between an AC power source that supplies power to a load between a first power source and a second power source according to a switching command,
Inserted between the first power source and the load, and in a closed state, the opening is greater than the current zero point interval, which is the time interval of the current zero point at which the current flowing from the first power source to the load becomes zero. A mechanical first switch for a short time;
It is inserted between the second power source and the load, and is opened more than the current zero point interval, which is the time interval of the current zero point at which the current flowing from the second power source to the load becomes zero in the closed state. A mechanical second switch for a short time;
Control means for receiving the switch command and reciprocally opening and closing the first and second switches according to the switch command so that simultaneous connection to the load of the first and second power supplies is avoided. When,
With
When the control means receives the switching command, the control means immediately causes the closed state switch in the closed state of the first and second switches to start the opening operation, and the first and second opening / closing operations. The open state switch in the open state of the open circuit is connected to the open state switch after the open state of the closed state switch has been completed and before a predetermined switching time has elapsed since the completion of the open state operation. Start the closing operation so that the closing operation of the state switch is completed ,
The first and second power sources are three-phase AC power sources having a frequency of 60 Hz,
The control means is lapsed after lapse of 6.8 milliseconds after addition of the switching command and the opening time of the closed state switch is added. The closing operation is started in the open state switch so that the closing operation of the open state switch is completed before the opening time of the closed state switch and the switching time have elapsed. A power supply switching device, characterized in that

A power source switching device that switches between an AC power source that supplies power to a load between a first power source and a second power source according to a switching command,
A mechanical first switch inserted between the first power source and the load;
A mechanical second switch inserted between the second power source and the load;
Control means for receiving the switch command and reciprocally opening and closing the first and second switches according to the switch command so that simultaneous connection to the load of the first and second power supplies is avoided. When,
Detecting means for detecting completion of the opening operation when the closed state switch in the closed state among the first and second switches starts the opening operation;
With
The closing operation time of the first and second switches is shorter than a predetermined switching time,
Upon receipt of the switching command, the control means immediately causes the closed state switch of the first and second switches to start the opening operation, and the completion of the opening operation is detected by the detecting means. A power supply switching device characterized in that at the time, the open state switch in the open state of the first and second switches starts a closing operation.

The power switching device according to any one of claims 1 to 4 , wherein the switching time is 10 milliseconds or less.