JP3754644B2

JP3754644B2 - Starting method for variable speed frequency converter

Info

Publication number: JP3754644B2
Application number: JP2001316170A
Authority: JP
Inventors: 章監崎; 毓鴎夏; 重明小川; チャンドヴァルマスレシ; 勲香田
Original assignee: Chubu Electric Power Co Inc; Mitsubishi Electric Corp
Current assignee: Chubu Electric Power Co Inc; Mitsubishi Electric Corp
Priority date: 2001-10-15
Filing date: 2001-10-15
Publication date: 2006-03-15
Anticipated expiration: 2021-10-15
Also published as: JP2003125538A

Description

【０００１】
【発明の属する技術分野】
この発明は、２台の可変速発電電動機で構成された可変速周波数変換機の始動方式に関するものである。
【０００２】
【従来の技術】
互いに異なる周波数が用いられている地域間の電力融通を行うのに、現在サイリスタ等より構成される周波数変換機が使用されている。しかしながら前記サイリスタ装置に比較して回転エネルギを利用可能な可変速発電電動機を２台直結して構成される可変速周波数変換機を使用した電力融通方式が最近注目されてきて、鋭意研究、実用化が進められている。しかしながらこの可変速発電電動機を用いた可変速周波数変換機の起動方式はまだ確立されておらず、従来の可変速揚水発電所の発電電動機の自己始動方式を利用することも可能とされているが後述するような欠点がある。その自己始動方式を以下簡単に説明する。
この自己始動方式は可変速発電電動機の固定子の巻線を短格遮断器又は断路器などで３相短絡し、回転子巻線に回転界磁を作るような３相励磁電圧を印加して、回転子の回転磁界と固定子コイルとの交鎖で生じるトルクによって回転子を回転させ、可変速発電電動機の回転子に印加する励磁電源の周波数を上げる／下げることによって回転子の回転速度を加速／減速し、回転子の回転速度が所定値以上になったら、励磁を減磁することによって固定子の電流をゼロ付近に減らし、固定子の短絡遮断器又は断路器を開いて短絡開放する。そして、固定子巻線の短絡遮断器又は断路器が開いたら、回転子に通常励磁と同等の励磁を印加して、固定子側電圧の位相、周波数及び大きさが系統側に一致するよう励磁を制御し、固定子の電圧が系統と一致するようになったら、固定子の主遮断器を投入して系統と並列する系統並列する。
【０００３】
【発明が解決しようとする課題】
しかしながら、このような従来の可変速発電電動機の自己始動方法には、次のような問題点がある。
（１）従来の自己始動方法によって始動する場合、回転子の回転速度が所定値以上になったら、励磁を減磁することによって固定子の電流をゼロ付近に減らし、固定子の短絡遮断器又は断路器を開いてから、回転子に通常励磁と同等の励磁を印加して、固定子の電圧が系統と一致したら固定子を系統と並列するが、励磁を減らしている間、回転速度が大幅に下がって可変速幅を超えるおそれがあり、並列が不可能となる不安定要素がある。
（２）また従来の自己始動方法によって始動する場合、可変速発電電動機の固定子の巻線を３相短絡し、回転子巻線に３相励磁電圧を印加して回転子を回転させ、回転子に印加する励磁電源の周波数を上げることによって回転子の回転速度を加速するが、励磁装置の容量が十分に大きくなければ、回転子の回転速度を所定値以上に上昇させることがむずかしく、起動のために励磁装置の定格を大きくしなければならず経済性を損なう。
（３）また従来の始動装置によって始動する場合、始動変換器、変圧器、始動制御装置などが別途必要となり高価となる。
この発明は前記のような課題を解消するためになされたもので、可変速幅を超えることなく、大容量の励磁装置を必要とせず、簡便な方式で電力融通を容易にかつスムースに可能とする可変速周波数変換機を始動方式を提供することを目的とする。
【０００４】
【課題を解決するための手段】
この発明に係る可変速周波数変換機の始動方式は、次のステップを有するものである。
（１）第１の可変速発電電動機の固定子巻線を第１の断路器で短絡し、第１の励磁変換器により回転子に励磁電圧を印加して、前記第１の可変速発電電動機の回転子とそれに直結する第２の可変速発電電動機の回転子を回転させるステップ。
（２）第１の励磁制御装置で励磁電源の周波数を制御することで回転速度を制御し、所定値以上の回転速度にするステップ。
（３）前記第２の可変速発電電動機の回転子に第２の励磁変換器を投入して通常励磁を印加、制御して固定子側電圧の位相、周波数、大きさを並列予定の第２の電力系統と一致させるステップ。
（４）第２の主遮断器を投入して前記第２の電力系統と並列するステップ。
（５）前記第２の可変速発電電動機の回転速度を一定に制御しながら、前記第１の可変速発電電動機の回転子励磁を減磁することによって固定子の電流を零近辺に減らすステップ。
（６）前記第１の断路器を開いて第１の可変速発電電動機の固定子巻線の短絡を開放し、回転子に通常励磁を印加、制御して固定子側電圧の位相、周波数、大きさを並列予定の前記第１の電力系統に一致させるステップ。
（７）第１の主遮断器を投入して前記第１の電力系統と並列することにより、前記第１の可変速発電電動機を前記第１の電力系統に並列するステップ。
【０００５】
また、次のステップを有するものである。
（１）第１の可変速発電電動機の固定子巻線を第１の断路器で短絡し、第１の励磁変換器により回転子に３相励磁電圧を印加して、前記第１の可変速発電電動機の回転子とそれに直結する第２の可変速発電電動機の回転子を回転させるステップ。
（２）第１の励磁制御装置で励磁電源の周波数を制御することで回転速度を制御し、所定値以上の回転速度にするステップ。
（３）第２の可変速発電電動機の固定子に設けられた第２の主遮断器を投入して第２の電力系統に並列するステップ。
（４）第２の励磁制御装置が第２の回転子電圧と第２の励磁変換器の出力電圧を入力し、前記出力電圧の位相、周波数および大きさを前記第２の回転子電圧と一致するよう制御後、第２の界磁遮断器を投入して回転子に通常励磁を印加するステップ。
（５）前記第２の可変速発電電動機の回転速度を一定に制御しながら、前記第１の可変速発電電動機の回転子励磁を減磁することによって固定子の電流を零近辺に減らすステップ。
（６）前記第１の断路器を開いて第１の可変速発電電動機の固定子巻線の短絡を開放し、回転子に通常励磁を印加、制御して固定子側電圧の位相、周波数、大きさを並列予定の前記第１の電力系統に一致させるステップ。
（７）第１の主遮断器を投入して前記第１の電力系統と並列することにより、前記第１の可変速発電電動機を前記第１の電力系統に並列するステップ。
【０００６】
またさらに、次のステップを有するものである。
（１）第１および第２の可変速発電電動機のそれぞれの固定子巻線を第１、第２の断路器で短絡し、第１、第２の励磁変換器によりそれぞれの回転子に励磁電圧を印加して、前記第１および第２の可変速発電電動機の回転子を回転させるステップ。
（２）第１、第２の励磁制御装置でそれぞれの回転子に印加する励磁電源の周波数を制御することで回転速度を制御し、所定値以上の回転速度にするステップ。
（３）前記第１の可変速発電電動機の回転速度を一定に制御しながら、前記第２の可変速発電電動機の回転子励磁を減磁することによって固定子の電流を零近辺に減らすステップ。
（４）前記第２の断路器を開いて第２の可変速発電電動機の固定子巻線の短絡を開放し、回転子に通常励磁を印加、制御して固定子側電圧の位相、周波数、大きさを並列予定の前記第２の電力系統に一致させるステップ。
（５）第２の主遮断器を投入して前記第２の電力系統と並列するステップ。
（６）前記第２の可変速発電電動機の回転速度を一定に制御しながら、前記第１の可変速発電電動機の回転子励磁を減磁することによって固定子の電流を零近辺に減らすステップ。
（７）前記第１の断路器を開いて第１の可変速発電電動機の固定子巻線の短絡を開放し、回転子に通常励磁を印加、制御して固定子側電圧の位相、周波数、大きさを並列予定の前記第１の電力系統に一致させるステップ。
（８）第１の主遮断器を投入して前記第１の電力系統と並列することにより、前記第１の可変速発電電動機を前記第１の電力系統に並列するステップ。
【０００７】
また、次のステップを有するものである。
（１）第１の可変速発電電動機の固定子巻線を第１の断路器で短絡し、第１および第２の励磁変換器を並列して前記第１および第２の可変速発電電動機の回転子に励磁電圧を印加し、前記第１および第２の可変速発電電動機の回転子を回転させるステップ。
（２）第１および第２の励磁制御装置で励磁電源の周波数を制御することで回転速度を制御し、所定値以上の回転速度にするステップ。
（３）前記第２の励磁変換器を前記第１の励磁変換器との並列から切り離して、前記第２の可変速発電電動機の回転子に通常励磁を印加、制御して固定子側電圧の位相、周波数、大きさを並列予定の第２の電力系統と一致させるステップ。
（４）第２の主遮断器を投入して前記第２の電力系統と並列するステップ。
（５）前記第２の可変速発電電動機の回転速度を一定に制御しながら、前記第１の可変速発電電動機の回転子励磁を減磁することによって固定子の電流を零近辺に減らすステップ。
（６）前記第１の断路器を開いて第１の可変速発電電動機の固定子巻線の短絡を開放し、回転子に通常励磁を印加、制御して固定子側電圧の位相、周波数、大きさを並列予定の前記第１の電力系統に一致させるステップ。
（７）第１の主遮断器を投入して前記第１の電力系統と並列することにより、前記第１の可変速発電電動機を前記第１の電力系統に並列するステップ。
【０００８】
またさらに次のステップを有するものである。
（１）第１の可変速発電電動機の固定子巻線を第１の断路器で短絡し、第１および第２の励磁変換器を並列して、前記第１および第２の可変速発電電動機の回転子に励磁電圧を印加して、前記第１および第２の可変速発電電動機の回転子を回転させるステップ。
（２）第１および第２の励磁制御装置で励磁電源の周波数を制御することで回転速度を制御し、所定値以上の回転速度にするステップ。
（３）前記第２の励磁変換器を前記第１の励磁変換器との並列から切り離し、第２の主遮断器を投入して前記第２の可変速発電電動機を第２の電力系統と並列するステップ。
（４）前記第２の励磁制御装置が第２の回転子の電圧と、第２の励磁変換器の出力電圧を入力し、前記出力電圧の位相、周波数および大きさを前記第２の回転子電圧と一致するよう制御するステップ。
（５）前記第２の可変速発電電動機の回転子に通常励磁を印加、回転速度を一定に制御しながら、前記第１の可変速発電電動機の回転子励磁を減磁することによって固定子の電流を零近辺に減らすステップ。
（６）前記第１の断路器を開いて第１の可変速発電電動機の固定子巻線の短絡を開放し、回転子に通常励磁を印加、制御して固定子側電圧の位相、周波数、大きさを並列予定の前記第１の電力系統に一致させるステップ。
（７）第１の主遮断器を投入して前記第１の電力系統と並列することにより、前記第１の可変速発電電動機を前記第１の電力系統に並列するステップ。
【０００９】
【発明の実施の形態】
実施の形態１．
この発明の実施の形態１の可変速周波数変換機の構成を図１に示す。図において、第１の可変速発電電動機Ｉ機１００と、第２の可変速発電電動機ＩＩ機２００とが同軸で接続され、それぞれの固定子２と１２が第１の主遮断器８と第２の主遮断器１８を介して第１の電力系統Ｉと第２の電力系統ＩＩに接続されており、それぞれの回転子１と１１が第１の励磁変換器４と第２の励磁変換器１４の２次側に接続されている。ここで電力系統Ｉは例えば周波数５０Ｈｚ地域に、電力系統ＩＩは６０Ｈｚ地域向きに電力供給が行われるものである。前記第１、第２の励磁変換器４、１４の１次側はそれぞれの励磁変圧器７と１７の２次側に接続され、制御入力側は各自の第１の励磁制御装置５および第２の励磁制御装置１５に接続されている。励磁変圧器７と１７の１次側はそれぞれ第１、第２の励磁遮断器６と１６を介して第１の系統Ｉと第２の系統ＩＩに接続する。１０は第１、第２の可変速発電電動機１００、２００の回転速度を測定するためのセンサで、９と１９はそれぞれ第１、第２の可変速発電電動機１００、２００の端子電圧Ｖ１ｇとＶ２ｇおよび第１、第２の系統Ｉ、ＩＩの電圧Ｖ１ｓ、Ｖ２ｓを測定するための電圧測定装置である。
【００１０】
次に、装置の動作について説明する。発電機電動機の回転速度が零の状態で、Ｉ機１００とＩＩ機２００の第１および第２の断路器３と１３、第１および第２の主遮断器８と１８、第１および第２の励磁遮断器６と１６を開き、Ｉ機１００の固定子２の三相巻線を第１の断路器３によって短絡させる。そして、第１の励磁遮断器６を投入して、回転子１に第１の励磁変換器４により３相励磁電圧を印加し、Ｉ機１００の回転子の回転磁界と固定子コイルとの交鎖で生じるトルクによってＩ機１００とＩＩ機２００の回転子を同時に回転させる。更に、第１の励磁制御装置５が回転速度センサー１０からの回転速度の信号ωｒを入力して、励磁電圧の周波数を上げることにより回転速度を加速する。回転速度が所定値以上になったら、第２の励磁遮断器１６を投入して第２の励磁変換器１５により回転子１１に通常励磁電圧を印加する。第２の励磁制御装置１５が電圧測定装置１９からＩＩ機２００の端子電圧Ｖ２ｇと系統ＩＩの電圧Ｖ２ｓを入力して、Ｖ２ｇの位相、周波数及び大きさがＶ２ｓのと一致するように第２の励磁変換器１４の出力を制御する。Ｖ２ｇの位相、周波数及び大きさがＶ２ｓのと一致したら、第２の主遮断器１８を投入してＩＩ機２００を第２の系統ＩＩと並列する。第２の励磁制御装置１５が同時に回転速度測定センサー１０から回転速度信号ωｒを入力して、回転速度を一定になるように第２の励磁変換器１４の出力を制御しながら、Ｉ機１００の第１の励磁制御装置５が励磁変換器４の出力を減磁することによってその固定子２の電流をゼロ付近に減らしたら、第１の断路器３を開き、第１の励磁変換器４が回転子１に通常励磁を印加して、第１の励磁制御装置５が電圧測定装置９から測定したＩ機１００の端子電圧Ｖ１ｇと系統Ｉの電圧Ｖ１ｓによって、Ｖ１ｇの位相、周波数及び大きさがＶ１ｓのと一致するように第１の励磁変換器４の出力を制御する。Ｖ１ｇの位相、周波数及び大きさがＶ１ｓのと一致したら、主遮断器８を投入してＩ機１００を第１の系統Ｉと並列する。
なお逆に、同じ手順で、ＩＩ機２００の励磁によってＩ機１００とＩＩ機２００を始動して、回転速度が所定値になったらＩ機１００の励磁を投入してＩ機１００を第１の系統Ｉと並列してから、ＩＩ機２００を第２の系統ＩＩと並列することもできる。このようにこの実施の形態１では、直結された２台の可変速発電電動機の片方を使用して始動し、残りの片方を先に系統に並列し、ついで、始動に使用した方を系統に並列するものである。従って、並列制御開始前に励磁装置の可変速幅の下限を下回るようなケースは発生しないという利点がある。
【００１１】
実施の形態２．
この発明の実施の形態２の可変速周波数変換機の構成を図２に示す。図において第１の可変速発電電動機Ｉ機１００と第２の可変速発電電動機ＩＩ機２００が同軸で接続され、それぞれの固定子２と１２が第１の主遮断器８と第２の主遮断器１８を介して第１の系統Ｉと第２の系統ＩＩに接続し、回転子１が第１の励磁変換器４の２次側に接続する。回転子１１は界磁遮断器２１を介して第２の励磁変換器１４の２次側に接続する。第１、第２の励磁変換器４と１４の１次側がそれぞれ励磁変圧器７と１７の２次側に接続し、制御入力側が第１、第２の励磁制御装置５と１５に接続する。励磁変圧器７と１７の１次側がそれぞれ第１、第２の励磁遮断器６と１６を介して第１の系統Ｉと第２の系統ＩＩと接続する。１０は発電機電動機の回転速度を測定するためのセンサーで、９はＩ機の端子電圧Ｖ１ｇと系統Ｉの電圧Ｖ１ｓを測定するための電圧測定装置で、１９は第２の回転子の電圧Ｖ２ｒと第２の励磁変換器１４の出力電圧Ｖ２ｅを測定するための電圧測定装置である。
【００１２】
次に、装置の動作について説明する。発電機電動機の回転速度が零の状態で、Ｉ機１００とＩＩ機２００の第１および第２の断路器３と１３、第１および第２の主遮断器８と１８、第１と第２の励磁遮断器６と１６、第２の界磁遮断器２１を開き、Ｉ機１００の固定子２の三相巻線を第１の断路器３によって短絡させる。そして、第１の励磁遮断器６を投入して、回転子１に第１の励磁変換器４により３相励磁電圧を印加し、回転子の回転磁界と固定子コイルとの交鎖で生じるトルクによってＩ機１００とＩＩ機２００の回転子を同時に回転させる。更に、第１の励磁制御装置５が回転速度センサー１０からの回転速度の信号ωｒを入力して、励磁電圧の周波数を上げることにより回転速度を加速する。回転速度が所定値以上になったら、第２の主遮断器１８を投入して、ＩＩ機２００を第２の系統ＩＩと並列する。そして、第２の励磁遮断器１６を投入し第２の励磁制御装置１５が電圧測定装置１９で測定した第２の回転子の電圧Ｖ２ｒと励磁変換器１４の出力の電圧Ｖ２ｅを入力して、Ｖ２ｅの位相、周波数及び大きさがＶ２ｒのと一致するように第２の励磁変換器１４の出力を制御する。Ｖ２ｅの位相、周波数及び大きさがＶ２ｒのと一致したら、第２の界磁遮断器２１を投入してＩＩ機２００の回転子１１の巻線に通常励磁を印加する。但し、この場合第２の電圧測定装置１９に入力していた回転子１１の電圧Ｖ２ｒは系統ＩＩの電圧Ｖ２ｓにつなぎかえる。第２の励磁制御装置１５が同時に回転速度測定センサー１０からの回転速度信号ωｒを入力して、回転速度を一定になるように第２の励磁変換器１４の出力を制御しながら、第１の励磁変換器４が出力を減することによってその固定子２の巻線の電流をゼロ付近に減らしたら、第１の断路器３を開き、第１の励磁変換器４が回転子１に通常励磁を印加して、電圧測定装置９で測定したＩ機１００の端子電圧Ｖ１ｇと第１の系統Ｉの電圧Ｖ１ｓによって、Ｖ１ｇの位相、周波数及び大きさがＶ１ｓのと一致するようにを第１の励磁変換器４の出力を制御する。Ｖ１ｇの位相、周波数及び周波数がＶ１ｓのと一致したら、第１の主遮断器８を投入してＩ機１００を系統Ｉと並列する。
なお逆に、同じ手順で、ＩＩ機２００の励磁によってＩ機１００とＩＩ機２００を始動して、回転速度が所定値になったらＩ機１００を第１の系統Ｉと並列してから、ＩＩ機２００を第２の系統ＩＩと並列することもできる。但し、この場合Ｉ機１００側に界磁遮断器２１を設け第１の励磁制御装置５の電圧測定装置９には回転子１の巻線電圧及び第１の励磁変換器４の出力電圧を入力し、ＩＩ機２００の第２の励磁制御装置１５の電圧測定装置１９にはＩＩ機２００の端子電圧と第２の系統ＩＩ電圧を入力する。このように先の実施の形態１が始動に使用しなかった並列する第２の可変速発電電動機に先に励磁を与えた後、固定子側で系統に並列する方式であるのに対して、この実施の形態２は２次側で並列する方式である。先ず無励磁で固定子側主遮断器を投入し、開放されている２次巻線の電圧に励磁装置の出力電圧、位相、周波数を合わせて励磁用遮断器を閉じるものである。
【００１３】
実施の形態３．
この発明の実施の形態３の可変速周波数変換機の始動方式について述べる。なおこの実施の形態３の可変速周波数変換機の構成は、実施の形態１で説明した図１と同様であるのでその構成説明は省略する。
【００１４】
次に、装置の動作について説明する。発電機電動機の回転速度が零の状態で、Ｉ機１００とＩＩ機２００の第１および第２の断路器３と１３、第１および第２の主遮断機８と１８、第１、第２の励磁遮断機６と１６を開き、Ｉ機１００の固定子２とＩＩ機２００の固定子１２の三相巻線をそれぞれ第１の断路器３と第２の断路器１３によって短絡させる。そして、第１の励磁遮断器６と第２の励磁遮断器１６をそれぞれ投入して、回転子巻線１と回転子巻線２にそれぞれ第１の励磁変換器４と第２の励磁変換器１４により３相励磁電圧を印加して、Ｉ機１００の回転子の回転磁界と固定子コイルとの交鎖で生じるトルク及びＩＩ機２００の回転子の回転磁界と固定子コイルとの交鎖で生じるトルクをあわせてＩ機１００とＩＩ機２００の回転子を同時回転させる。更に、第１の励磁制御装置５と第２の励磁制御装置１５がそれぞれ回転速度センサー１０からの回転速度信号ωｒを入力して、それぞれの励磁電圧の周波数を上げることにより同時に回転速度を加速する。回転速度が所定値以上になったら、第２の励磁制御装置１５が回転速度を保つように第２の励磁変換器１４の出力を制御しながら、第１の励磁制御装置５が第１の励磁変換器４の出力を減すことによって固定子１の巻線電流を零にしたら、第１の断路器３を開く。そして、第１の励磁制御装置５が電圧測定装置９からＩ機１００の端子電圧Ｖ１ｇと第１の系統Ｉの電圧Ｖ１ｓを入力して、Ｖ１ｇの位相、周波数及び大きさがＶ１ｓのと一致するように第１の励磁変換器４の出力を制御する。Ｖ１ｇの位相、周波数及び大きさがＶ１ｓのと一致したら、第１の主遮断器８を投入してＩ機１００を系統Ｉと並列する。並列した第１の励磁制御装置５が回転速度を一定に制御しながら、第２の励磁変換器１４の出力を減することによって固定子１２の巻線の電流を零にしたら、第２の断路器１３を開く。同時に第２の励磁制御装置１５が電圧測定装置１９からＩＩ機２００の端子電圧Ｖ２ｇと第２の系統ＩＩの電圧Ｖ２ｓを入力して、Ｖ２ｇの位相、周波数及び大きさがＶ２ｓのと一致するように第２の励磁変換器１４の出力を制御する。Ｖ２ｇの位相、周波数及び大きさがＶ２ｓのと一致したら、ＩＩ機２００の第２の主遮断器１８を投入してＩＩ機２００を第２の系統ＩＩと並列する。なお逆に、同じ手順で、Ｉ機１００とＩＩ機２００の励磁によってＩ機１００とＩＩ機２００を同時に始動し、ＩＩ機２００を先に第２の系統ＩＩと並列することもできる。つまりこの実施の形態３では、励磁装置を大きくすることなく２台の可変速発電電動機を同時に使って、始動、加速する方式であり、励磁装置容量を大きくすることなく定格速度まで加速できるという利点がある。
【００１５】
実施の形態４．
この発明の実施の形態４の可変速周波数変換機の構成を図３に示す。図において第１の可変速発電電動機Ｉ機１００と第２の可変速発電電動機ＩＩ機２００が同軸で接続され、それぞれの固定子巻線２と１２が第１の主遮断器８と第２の主遮断器１８を介して第１の系統Ｉと第２の系統ＩＩに抜続し、それぞれの回転子巻線１と１１が第１、第２の励磁変換器４と１４の２次側に接続する。第１、第２の励磁変換器４と１４の１次側がそれぞれ励磁変圧器７と１７の２次側に接続し、制御入力側が第１、第２の励磁制御装置５と１５に接続する。励磁変圧器７と１７の１次側が第１、第２の励磁遮断器６と１６を介して第１の系統Ｉと第２の系統ＩＩに接続する。又、第１、第２の励磁変換器４と励磁変換器１４の出力側は第１、第２の界磁遮断器２０と２１を介して回転子１と１１に接続され、２次側を並列接続するための第３の界磁遮断器２２を介して接続される。１０は発電機電動機の回転速度を測定するためのセンサーで、９と１９はそれぞれＩ機１００とＩＩ機２００の端子電圧Ｖ１ｇとＶ２ｇ及び第１の系統Ｉと第２の系統ＩＩの電圧Ｖ１ｓとＶ２ｓを測定するための電圧測定装置である。
【００１６】
次に、装置の動作について説明する。発電機電動機の回転速度が零の状態で、Ｉ機１００とＩＩ機２００の第１および第２の断路器３と１３、第１および第２の主遮断器８と１８、第１、第２の励磁遮断器６と１６を開き、Ｉ機１００の固定子２の三相巻線を第１の断路器３によって短縮させる。第１、第３の界磁遮断器２０、２２を投入して、第１の励磁変換器４と第２の励磁変換器１４を並列させる。そして、第１および第２の励磁遮断器６と１６を投入して、回転子巻線１および１１に並列した第１の励磁変換器４と第２の励磁変換器１４により３相励磁電圧を印加して、回転子の回転磁界と固定子コイルとの交鎖で生じるトルクによってＩ機１００とＩＩ機２００の回転子を同時回転させる。更に、第１および第２の励磁制御装置５、１５が回転速度センサー１０からの回転速度信号ωｒを入力して、第１および第２の励磁変換器４、１４の出力電圧の周波数を上げることにより回転速度を加速する。回転速度が所定値以上になったら、第２の励磁変換器１４を止め、第３の界磁遮断器２２を開き、第２の界磁遮断器２１を投入して第２の励磁変換器１４から回転子１１の巻線に通常励磁を印加する。第１の励磁制御装置５が回転速度を一定に制御しながら、第２の励磁制御装置１５が電圧測定装置１９からＩＩ機２００の端子電圧Ｖ２ｇと第２の系統ＩＩの電圧Ｖ２ｓを入力して、Ｖ２ｇの位相、周波数及び大きさがＶ２ｓのと一致するように第２の励磁変換器１４の出力を制御する。Ｖ２ｇの位相、周波数及び大きさがＶ２ｓのと一致したら、第２の主遮断器１８を投入してＩＩ機２００を第２の系統ＩＩと並列する。第２の励磁制御装置１５が同時に回転速度測定センサー１０からの回転速度信号ωｒを入力して、回転速度を一定になるように第２の励磁変換器１４の出力を制御しながら、第１の励磁変換器４が励磁出力を減磁することによってその固定子２の巻線の電流をゼロ付近に減らしたら、第１の断路器３を開き、第１の励磁変換器４が回転子１に通常励磁を印加して、電圧測定装置９から測定したＩ機１００の端子電圧Ｖ１ｇと第１の系統Ｉの電圧Ｖ１ｓによって、Ｖ１ｇの位相、周波数及び大きさがＶ１ｓのと一致するようにを制御する。Ｖ１ｇの位相、周波数及び大きさがＶ１ｓのと一致したら、Ｉ機１００の第１の主遮断器８を投入してＩ機１００を第１の系統Ｉと並列する。
なお逆に、同じ手順で、Ｉ機１００とＩＩ機２００の励磁変換器４、１４を並列してＩＩ機２００に励磁を印加することによつてＩ機１００とＩＩ機２００を始動して、そして回転速度が所定値まで加速されたらＩ機１００に第１の励磁変換器４を投入して、Ｉ機１００を先に第１の系統Ｉと並列してからＩＩ機２００を第２の系統ＩＩと並列することもできる。つまりこの実施の形態４は、始動開始前に励磁装置２台を並列して可変速発電電動機１台に励磁を与える回路構成にし、１台で加速を行い、並列時は励磁装置１台を切り離し本来の励磁を与え固定子側で同期並列を行う方式である。
【００１７】
実施の形態５．
この発明の実施の形態５の可変速周波数変換機の構成を図４に示す。図において第１の可変速発電電動機Ｉ機１００と第２の可変速発電電動機ＩＩ機２００が同軸で接続され、それぞれの固定子巻線２と１２が第１の主遮断器８と第２の主遮断器１８を介して第１の系統Ｉと第２の系統ＩＩに接続し、それぞれの回転子巻線１と１１が第１、第２の励磁変換器４と１４の２次側に接続する。第１、第２の励磁変換器４と１４の１次側がそれぞれ励磁変圧器７と１７の２次側に接続し、制御入力側が第１、第２の励磁制御装置５と１５に接続する。励磁変圧器７と１７の１次側がそれぞれ第１、第２の励磁遮断器６と１６を介して第１の系統Ｉと第２の系統ＩＩに接続する。又、第１、第２の励磁変換器４と励磁変換器１４の出力側は第１、第２の界磁遮断器２０と２１を介して回転子１と１１に接続し、２次側を並列するための第３の界磁遮断器２２を介して接続する。１０は発電機電動機の回転速度を測定するためのセンサーで、９はＩ機１００の端子電圧Ｖ１ｇと系統Ｉの電圧Ｖ１ｓを測定するための電圧測定装置で、１９は第２の回転子の電圧Ｖ２ｒと第２の励磁変換器１４の出力の電圧Ｖ２ｅを測定するための電圧測定装置である。
【００１８】
次に、装置の動作について説明する。発電機電動機の回転速度が零の状態で、Ｉ機１００とＩＩ機２００の第１および第２の断路器３と１３、第１、第２の主遮断機８と１８、第１、第２の励磁遮断機６と１６を開き、Ｉ機１００の固定子２の三相巻線を第１の断路器３によって短絡させる。第１、第３の界磁遮断器２０、２２を投入して、第１の励磁変換器４と第２の励磁変換器１４を並列させる。そして、第１および第２の励磁遮断器６、１６を投入して、回転子巻線１および１１に並列した第１の励磁変換器４と第２の励磁変換器１４により３相励磁電圧を印加して、回転子の回転磁界と固定子コイルとの交鎖で生じるトルクによってＩ機１００とＩＩ機２００の回転子を同時に回転させる。更に、第１および第２の励磁制御装置５、１５が回転速度センサー１０からの回転速度信号ωｒを入力して、第１の励磁変換器５の出力電圧の周波数を上げることにより回転速度を加速する。回転速度が所定値以上になったら、第２の励磁変換器１４を止め、第３の界磁遮断器２２を開き、ＩＩ機２００の第２の主遮断器１８を投入して、ＩＩ機２００を第２の系統ＩＩと並列する。
そして、第２の励磁制御装置１５が電圧測定装置１９で測定した第２の回転子１１の電圧Ｖ２ｒと第２の励磁変換器１４の電圧Ｖ２ｅを入力して、Ｖ２ｅの位相、周波数及び大きさがＶ２ｒのと一致するように第２の励磁変換器１４の出力を制御する。Ｖ２ｅの位相、周波数及び大きさがＶ２ｒのと一致したら、第２の界磁遮断器２１を投入してＩＩ機２００の回転子１１の巻線に通常励磁を印加する。但し、この場合第２の電圧測定装置１９に入力していた回転子１１の電圧Ｖ２ｒは系統ＩＩの電圧Ｖ２ｓにつなぎかえる。
第２の励磁制御装置１５が同時に回転速度測定センサーからの回転速度信号を入力して、回転速度を一定になるように第２の励磁変換器１４の出力を制御しながら、第１の励磁変換器４が励磁出力を減磁することによってその固定子２の巻線の電流をゼロ付近に減らしたら、第１の断路器３を開き、第１の励磁変換器４が回転子１に通常励磁を印加して、電圧測定装置９から測定したＩ機１００の端子電圧Ｖ１ｇと系統Ｉの電圧Ｖ１ｓによって、Ｖ１ｇの位相、周波数及び大きさがＶ１ｓのと一致するようにを制御する。Ｖ１ｇの位相、周波数及び大きさがＶ１ｓのと一致したら、Ｉ機１００の第１の主遮断器８を投入してＩ機１００を第１の系統Ｉと並列する。
なお逆に、同じ手順で、Ｉ機１００とＩＩ機２００の励磁変換器４、１４を並列してＩＩ機２００に励磁を印加することによってＩ機１００とＩＩ機２００を始動して、そして回転速度が所定値まで加速されたらＩ機１００を先に第１の系統Ｉと並列してから、ＩＩ機２００を第２の系統ＩＩと並列することもできる。但し、この場合Ｉ機１００の第１の励磁制御装置５の電圧測定装置９には回転子１の巻線電圧および第１の励磁変換器４の出力電圧を入力し、ＩＩ機２００の第２の励磁制御装置１５の電圧測定装置１９にはＩＩ機２００の端子電圧と第２の系統ＩＩ電圧を入力する。つまりこの実施の形態５と先の実施の形態４との相違は、最初に並列する可変速発電電動機の並列を励磁側で行うことにある。
なお、以上説明した実施の形態１〜５で第１、第２の断路器３、１３については遮断器を使用してもよい。
【００１９】
【発明の効果】
この発明は以上述べたような始動方式を採用しているので、以下に示すような効果を奏する。
【００２０】
直結された２台の可変速発電電動機の片方の１台をまず始動し、残りの他の１台を先に電力系統に並列し、引き続き始動に使用した先の１台を並列する方式を採用しているので、励磁装置の可変速幅の下限を下回るようなケースの発生がなく、安価な装置で容易にかつスムースに異なる系統間の電力融通が行えるという利点がある。
【００２１】
また、直結された２台の可変速発電電動機の片方の１台をまず始動し、残りの他の１台を無励磁の状態で第２の主遮断器を投入して電力系統に並列しているので、前記と同様の効果を奏する。
【００２２】
さらにまた、２台の可変速発電電動機を同時に始動、加速する方式であるので、励磁装置の容量を大きくする必要が無く、加速トルク不足で定格速度まで加速出来ないようなケースに対して充分対応可能という効果を奏する。
【００２３】
また、始動開始前に励磁装置２台を並列にし、可変速発電電動機１台に励磁を行う方式であるので、前記と同様の効果を奏する。
【００２４】
またさらに、最初に系統に並列する可変速発電電動機の並列を、励磁側で行っているので、前記と同様の効果を奏する。
【図面の簡単な説明】
【図１】この発明の実施の形態１の可変速周波数変換機の構成を示す図である。
【図２】この発明の実施の形態２の可変速周波数変換機の構成を示す図である。
【図３】この発明の実施の形態４の可変速周波数変換機の構成を示す図である。
【図４】この発明の実施の形態５の可変速周波数変換機の構成を示す図である。
【符号の説明】
１，１１回転子、２，１２固定子、３第１の断路器、
４第１の励磁変換器、５第１の励磁制御装置、６第１の励磁遮断器、
７，１７励磁変圧器、８第１の主遮断器、９，１９電圧測定器、
１０センサ、１３第２の断路器、１４第２の励磁変換器、
１５第２の励磁制御装置、１６第２の励磁遮断器、１８第２の主遮断器、
２０第１の界磁遮断器、２１第２の界磁遮断器、２２第３の界磁遮断器、
１００第１の可変速発電電動機、２００第２の可変速発電電動機。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a starting method of a variable speed frequency converter composed of two variable speed generator motors.
[0002]
[Prior art]
Currently, a frequency converter composed of a thyristor or the like is used for power interchange between regions where different frequencies are used. However, compared with the thyristor device, an electric power interchange system using a variable speed frequency converter constructed by directly connecting two variable speed generator motors that can use rotational energy has recently attracted attention. Is underway. However, the starting method of the variable speed frequency converter using this variable speed generator motor has not been established yet, and it is possible to use the conventional self-starting method of the generator motor of the variable speed pumped storage power plant. There are drawbacks as described below. The self-starting method will be briefly described below.
In this self-starting method, the stator winding of the variable speed generator motor is short-circuited with a short circuit breaker or disconnector for three phases, and a three-phase excitation voltage that creates a rotating field in the rotor winding is applied. Rotating the rotor by the torque generated by the crossing of the rotating magnetic field of the rotor and the stator coil, and increasing / decreasing the frequency of the excitation power applied to the rotor of the variable speed generator motor, When acceleration / deceleration is performed and the rotor speed exceeds the specified value, the current of the stator is reduced to near zero by demagnetizing the excitation, and the short circuit breaker or disconnector of the stator is opened to open the short circuit. . When the stator coil short circuit breaker or disconnector opens, apply excitation equivalent to normal excitation to the rotor and excite the phase, frequency, and magnitude of the stator side voltage to match the system side. When the stator voltage matches the system, the main circuit breaker of the stator is turned on and the system is paralleled with the system.
[0003]
[Problems to be solved by the invention]
However, the conventional self-starting method of the variable speed generator motor has the following problems.
(1) When starting with the conventional self-starting method, when the rotational speed of the rotor exceeds a predetermined value, the stator current is reduced to near zero by demagnetizing the excitation, and the stator short circuit breaker or After opening the disconnector, apply excitation equivalent to normal excitation to the rotor, and when the stator voltage matches the system, the stator is paralleled with the system, but the rotation speed greatly increases while the excitation is reduced. There is an unstable element that may be unable to be parallelized.
(2) When starting with the conventional self-starting method, the stator winding of the variable speed generator motor is short-circuited in three phases, and the rotor is rotated by applying a three-phase excitation voltage to the rotor winding. Rotation speed of the rotor is accelerated by increasing the frequency of the excitation power supply applied to the rotor. However, if the capacity of the exciter is not sufficiently large, it is difficult to increase the rotation speed of the rotor to a predetermined value or more. Therefore, it is necessary to increase the rating of the exciter and impair the economy.
(3) Further, when starting with a conventional starter, a starter converter, a transformer, a starter control device, etc. are required separately, which is expensive.
The present invention has been made to solve the above-described problems, and does not exceed the variable speed range, does not require a large-capacity exciter, and enables easy and smooth power interchange with a simple method. An object of the present invention is to provide a starting method for a variable speed frequency converter.
[0004]
[Means for Solving the Problems]
The starting method of the variable speed frequency converter according to the present invention includes the following steps.
(1) A stator winding of a first variable speed generator-motor is short-circuited by a first disconnector, an excitation voltage is applied to the rotor by a first excitation converter, and the first variable-speed generator-motor is And rotating the rotor of the second variable speed generator-motor directly connected thereto.
(2) A step of controlling the rotation speed by controlling the frequency of the excitation power source with the first excitation control device so that the rotation speed is a predetermined value or more.
(3) A second excitation converter is inserted into the rotor of the second variable speed generator motor to apply and control normal excitation, and the phase, frequency and magnitude of the stator side voltage are scheduled to be paralleled. Matching with the power grid of
(4) A step of turning on the second main circuit breaker and paralleling with the second power system.
(5) A step of reducing the stator current to near zero by demagnetizing the rotor excitation of the first variable speed generator motor while controlling the rotation speed of the second variable speed generator motor to be constant.
(6) Open the first disconnector to open the short circuit of the stator winding of the first variable speed generator motor, and apply and control the normal excitation to the rotor to control the phase, the frequency of the stator side voltage, Matching the magnitude to the first power system scheduled in parallel.
(7) A step of paralleling the first variable speed generator-motor to the first power system by turning on the first main circuit breaker and paralleling the first power breaker.
[0005]
Moreover, it has the following steps.
(1) The stator winding of the first variable speed generator-motor is short-circuited by the first disconnector, and a three-phase excitation voltage is applied to the rotor by the first excitation converter, so that the first variable speed generator is Rotating the rotor of the generator motor and the rotor of the second variable speed generator motor directly connected thereto;
(2) A step of controlling the rotation speed by controlling the frequency of the excitation power source with the first excitation control device so that the rotation speed is a predetermined value or more.
(3) A step of turning on the second main circuit breaker provided in the stator of the second variable speed generator motor and paralleling the second main circuit breaker.
(4) The second excitation control device inputs the second rotor voltage and the output voltage of the second excitation converter, and the phase, frequency and magnitude of the output voltage coincide with the second rotor voltage. After the control, the second field breaker is turned on to apply normal excitation to the rotor.
(5) A step of reducing the stator current to near zero by demagnetizing the rotor excitation of the first variable speed generator motor while controlling the rotation speed of the second variable speed generator motor to be constant.
(6) Open the first disconnector to open the short circuit of the stator winding of the first variable speed generator motor, and apply and control the normal excitation to the rotor to control the phase, the frequency of the stator side voltage, Matching the magnitude to the first power system scheduled in parallel.
(7) A step of paralleling the first variable speed generator-motor to the first power system by turning on the first main circuit breaker and paralleling the first power breaker.
[0006]
Furthermore, it has the following steps.
(1) The stator windings of the first and second variable speed generator motors are short-circuited by the first and second disconnectors, and the excitation voltages are applied to the respective rotors by the first and second excitation converters. And rotating the rotors of the first and second variable speed generator-motors.
(2) A step of controlling the rotation speed by controlling the frequency of the excitation power source applied to each rotor by the first and second excitation control devices, so that the rotation speed is equal to or higher than a predetermined value.
(3) The step of reducing the stator current to near zero by demagnetizing the rotor excitation of the second variable speed generator motor while controlling the rotation speed of the first variable speed generator motor to be constant.
(4) Open the second disconnector to open the short circuit of the stator winding of the second variable speed generator motor, and apply and control the normal excitation to the rotor to control the phase, the frequency of the stator side voltage, Matching the magnitude to the second power system scheduled for parallel.
(5) A step of turning on the second main circuit breaker and paralleling with the second power system.
(6) A step of reducing the stator current to near zero by demagnetizing the rotor excitation of the first variable speed generator motor while controlling the rotation speed of the second variable speed generator motor to be constant.
(7) Open the first disconnector to open the short circuit of the stator winding of the first variable speed generator motor, and apply and control the normal excitation to the rotor to control the phase, frequency of the stator side voltage, Matching the magnitude to the first power system scheduled in parallel.
(8) A step of paralleling the first variable speed generator-motor to the first power system by turning on a first main circuit breaker and paralleling the first power breaker.
[0007]
Moreover, it has the following steps.
(1) The stator winding of the first variable speed generator-motor is short-circuited by the first disconnector, and the first and second variable-speed generator motors are paralleled with the first and second excitation converters. Applying excitation voltage to the rotor to rotate the rotor of the first and second variable speed generator motors;
(2) A step of controlling the rotation speed by controlling the frequency of the excitation power source with the first and second excitation control devices so that the rotation speed is equal to or higher than a predetermined value.
(3) The second excitation converter is disconnected from the parallel with the first excitation converter, and normal excitation is applied to and controlled by the rotor of the second variable speed generator motor to Matching the phase, frequency, and magnitude with the second power system scheduled in parallel;
(4) A step of turning on the second main circuit breaker and paralleling with the second power system.
(5) A step of reducing the stator current to near zero by demagnetizing the rotor excitation of the first variable speed generator motor while controlling the rotation speed of the second variable speed generator motor to be constant.
(6) Open the first disconnector to open the short circuit of the stator winding of the first variable speed generator motor, and apply and control the normal excitation to the rotor to control the phase, the frequency of the stator side voltage, Matching the magnitude to the first power system scheduled in parallel.
(7) A step of paralleling the first variable speed generator-motor to the first power system by turning on the first main circuit breaker and paralleling the first power breaker.
[0008]
Furthermore, it has the following steps.
(1) A stator winding of the first variable speed generator-motor is short-circuited by a first disconnector, and the first and second excitation converters are arranged in parallel, and the first and second variable-speed generator motors Applying an excitation voltage to the first rotor and rotating the rotor of the first and second variable speed generator-motors.
(2) A step of controlling the rotation speed by controlling the frequency of the excitation power source with the first and second excitation control devices so that the rotation speed is equal to or higher than a predetermined value.
(3) The second excitation converter is disconnected from the parallel with the first excitation converter, the second main circuit breaker is turned on, and the second variable speed generator motor is connected in parallel with the second power system. Step to do.
(4) The second excitation control device inputs the voltage of the second rotor and the output voltage of the second excitation converter, and sets the phase, frequency and magnitude of the output voltage to the second rotor. Control to match the voltage.
(5) Applying normal excitation to the rotor of the second variable speed generator-motor and demagnetizing the rotor excitation of the first variable-speed generator motor while controlling the rotation speed to be constant. Reducing the current to near zero.
(6) Open the first disconnector to open the short circuit of the stator winding of the first variable speed generator motor, and apply and control the normal excitation to the rotor to control the phase, the frequency of the stator side voltage, Matching the magnitude to the first power system scheduled in parallel.
(7) A step of paralleling the first variable speed generator-motor to the first power system by turning on the first main circuit breaker and paralleling the first power breaker.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
The configuration of the variable speed frequency converter according to the first embodiment of the present invention is shown in FIG. In the figure, a first variable speed generator-motor I machine 100 and a second variable-speed generator motor II machine 200 are connected coaxially, and the respective stators 2 and 12 are connected to the first main circuit breaker 8 and the second Are connected to the first power system I and the second power system II via the main circuit breaker 18, and the rotors 1 and 11 are respectively connected to the first excitation converter 4 and the second excitation converter 14. Is connected to the secondary side. Here, for example, the electric power system I is supplied to a frequency 50 Hz area, and the electric power system II is supplied to a 60 Hz area. The primary sides of the first and second excitation converters 4 and 14 are connected to the secondary sides of the respective excitation transformers 7 and 17, and the control input side is the first excitation control device 5 and the second one of the respective ones. The excitation control device 15 is connected. The primary sides of the excitation transformers 7 and 17 are connected to the first system I and the second system II via first and second excitation circuit breakers 6 and 16, respectively. 10 is a sensor for measuring the rotational speed of the first and second variable speed generator-motors 100 and 200, and 9 and 19 are terminal voltages V1g and V2g of the first and second variable-speed generator motors 100 and 200, respectively. And a voltage measuring device for measuring the voltages V1s and V2s of the first and second systems I and II.
[0010]
Next, the operation of the apparatus will be described. When the rotational speed of the generator motor is zero, the first and second disconnectors 3 and 13 of the I machine 100 and the II machine 200, the first and second main circuit breakers 8 and 18, the first and second And the three-phase winding of the stator 2 of the I machine 100 are short-circuited by the first disconnector 3. Then, the first excitation circuit breaker 6 is turned on, and a three-phase excitation voltage is applied to the rotor 1 by the first excitation converter 4 so that the rotating magnetic field of the rotor of the I machine 100 and the stator coil are interchanged. The rotors of the I machine 100 and the II machine 200 are simultaneously rotated by the torque generated in the chain. Further, the first excitation control device 5 inputs the rotation speed signal ωr from the rotation speed sensor 10 and increases the excitation voltage frequency to accelerate the rotation speed. When the rotation speed exceeds a predetermined value, the second excitation circuit breaker 16 is turned on, and the normal excitation voltage is applied to the rotor 11 by the second excitation converter 15. The second excitation control device 15 inputs the terminal voltage V2g of the II machine 200 and the voltage V2s of the system II from the voltage measuring device 19, and the second excitation control device 15 is set so that the phase, frequency, and magnitude of V2g coincide with V2s. The output of the excitation converter 14 is controlled. When the phase, frequency, and magnitude of V2g coincide with V2s, the second main circuit breaker 18 is turned on to make the II machine 200 parallel to the second system II. The second excitation control device 15 simultaneously receives the rotation speed signal ωr from the rotation speed measurement sensor 10 and controls the output of the second excitation converter 14 so that the rotation speed becomes constant. When the first excitation control device 5 demagnetizes the output of the excitation converter 4 to reduce the current of the stator 2 to near zero, the first disconnector 3 is opened, and the first excitation converter 4 The normal excitation is applied to the rotor 1, and the phase, frequency and magnitude of V1g are determined by the terminal voltage V1g of the I machine 100 and the voltage V1s of the system I measured by the first excitation control device 5 from the voltage measuring device 9. The output of the first excitation converter 4 is controlled so as to coincide with V1s. When the phase, frequency, and magnitude of V1g coincide with V1s, the main circuit breaker 8 is turned on to parallel the I machine 100 with the first system I.
Conversely, in the same procedure, the I machine 100 and the II machine 200 are started by the excitation of the II machine 200, and when the rotation speed reaches a predetermined value, the I machine 100 is turned on to make the I machine 100 the first machine. The II machine 200 can be paralleled with the second system II after being paralleled with the system I. As described above, in the first embodiment, one of the two directly connected variable speed generator motors is used for starting, the remaining one is first connected in parallel to the system, and then the one used for starting is connected to the system. They are parallel. Therefore, there is an advantage that a case that falls below the lower limit of the variable speed range of the excitation device does not occur before the parallel control is started.
[0011]
Embodiment 2. FIG.
The configuration of the variable speed frequency converter according to Embodiment 2 of the present invention is shown in FIG. In the figure, the first variable speed generator-motor I machine 100 and the second variable-speed generator motor II machine 200 are connected coaxially, and the respective stators 2 and 12 are connected to the first main circuit breaker 8 and the second main circuit breaker. The rotor 1 is connected to the secondary side of the first excitation converter 4 by connecting to the first system I and the second system II via the generator 18. The rotor 11 is connected to the secondary side of the second excitation converter 14 via the field breaker 21. The primary sides of the first and second excitation converters 4 and 14 are connected to the secondary sides of the excitation transformers 7 and 17, respectively, and the control input side is connected to the first and second excitation control devices 5 and 15. The primary sides of the excitation transformers 7 and 17 are connected to the first system I and the second system II via first and second excitation circuit breakers 6 and 16, respectively. 10 is a sensor for measuring the rotational speed of the generator motor, 9 is a voltage measuring device for measuring the terminal voltage V1g of the I machine and the voltage V1s of the system I, and 19 is the voltage V2r of the second rotor. And a voltage measuring device for measuring the output voltage V2e of the second excitation converter 14.
[0012]
Next, the operation of the apparatus will be described. With the rotational speed of the generator motor being zero, the first and second disconnectors 3 and 13 of the I machine 100 and II machine 200, the first and second main circuit breakers 8 and 18, the first and second The excitation breakers 6 and 16 and the second field breaker 21 are opened, and the three-phase winding of the stator 2 of the I machine 100 is short-circuited by the first disconnector 3. Then, the first excitation circuit breaker 6 is turned on, a three-phase excitation voltage is applied to the rotor 1 by the first excitation converter 4, and torque generated by the crossing of the rotating magnetic field of the rotor and the stator coil. To simultaneously rotate the rotors of the I machine 100 and the II machine 200. Further, the first excitation control device 5 inputs the rotation speed signal ωr from the rotation speed sensor 10 and increases the excitation voltage frequency to accelerate the rotation speed. When the rotational speed reaches a predetermined value or more, the second main circuit breaker 18 is turned on, and the II machine 200 is placed in parallel with the second system II. Then, the second excitation circuit breaker 16 is turned on, and the second excitation control device 15 inputs the second rotor voltage V2r measured by the voltage measurement device 19 and the output voltage V2e of the excitation converter 14, The output of the second excitation converter 14 is controlled so that the phase, frequency, and magnitude of V2e coincide with those of V2r. When the phase, frequency, and magnitude of V2e coincide with V2r, the second field breaker 21 is turned on and normal excitation is applied to the winding of the rotor 11 of the II machine 200. However, in this case, the voltage V2r of the rotor 11 input to the second voltage measuring device 19 is switched to the voltage V2s of the system II. The second excitation control device 15 inputs the rotational speed signal ωr from the rotational speed measuring sensor 10 at the same time, and controls the output of the second excitation converter 14 so that the rotational speed becomes constant. When the excitation converter 4 reduces the output of the stator 2 by reducing the output to near zero, the first disconnector 3 is opened, and the first excitation converter 4 is normally excited in the rotor 1. And the phase, frequency, and magnitude of V1g coincide with V1s by the terminal voltage V1g of the I machine 100 measured by the voltage measuring device 9 and the voltage V1s of the first system I. The output of the excitation converter 4 is controlled. When the phase, frequency, and frequency of V1g coincide with V1s, the first main circuit breaker 8 is turned on to parallel the I machine 100 with the system I.
Conversely, in the same procedure, the I machine 100 and the II machine 200 are started by the excitation of the II machine 200, and when the rotational speed reaches a predetermined value, the I machine 100 is paralleled with the first system I, and then the II machine 200 is turned on. The machine 200 can also be paralleled with the second system II. In this case, however, a field breaker 21 is provided on the I machine 100 side, and the winding voltage of the rotor 1 and the output voltage of the first excitation converter 4 are input to the voltage measuring device 9 of the first excitation control device 5. The terminal voltage of the II machine 200 and the second system II voltage are input to the voltage measuring device 19 of the second excitation control device 15 of the II machine 200. In this way, the previous embodiment 1 is a system in which the second variable speed generator motor in parallel that was not used for starting is first excited and then paralleled to the system on the stator side, The second embodiment is a method of paralleling on the secondary side. First, the stator-side main circuit breaker is turned on without excitation, and the excitation circuit breaker is closed by adjusting the output voltage, phase, and frequency of the excitation device to the voltage of the opened secondary winding.
[0013]
Embodiment 3 FIG.
A starting system for the variable speed frequency converter according to the third embodiment of the present invention will be described. The configuration of the variable speed frequency converter according to the third embodiment is the same as that of FIG. 1 described in the first embodiment, and therefore the description of the configuration is omitted.
[0014]
Next, the operation of the apparatus will be described. When the rotational speed of the generator motor is zero, the first and second disconnectors 3 and 13 of the I machine 100 and the II machine 200, the first and second main circuit breakers 8 and 18, the first and second And the three-phase windings of the stator 2 of the I machine 100 and the stator 12 of the II machine 200 are short-circuited by the first disconnector 3 and the second disconnector 13, respectively. Then, the first excitation circuit breaker 6 and the second excitation circuit breaker 16 are turned on, and the first excitation converter 4 and the second excitation converter are respectively applied to the rotor winding 1 and the rotor winding 2. 14, the three-phase excitation voltage is applied, and the torque generated by the crossing of the rotating magnetic field of the rotor of I machine 100 and the stator coil and the crossing of the rotating magnetic field of the rotor of II machine 200 and the stator coil The rotors of the I machine 100 and the II machine 200 are simultaneously rotated in accordance with the generated torque. Further, the first excitation control device 5 and the second excitation control device 15 each receive the rotational speed signal ωr from the rotational speed sensor 10 and simultaneously increase the frequency of the respective excitation voltages to simultaneously accelerate the rotational speed. . When the rotation speed exceeds a predetermined value, the first excitation control device 5 controls the output of the second excitation converter 14 so that the second excitation control device 15 maintains the rotation speed, and the first excitation control device 5 performs the first excitation control. When the winding current of the stator 1 is reduced to zero by reducing the output of the converter 4, the first disconnector 3 is opened. Then, the first excitation control device 5 inputs the terminal voltage V1g of the I machine 100 and the voltage V1s of the first system I from the voltage measuring device 9, and the phase, frequency, and magnitude of V1g coincide with V1s. Thus, the output of the first excitation converter 4 is controlled. When the phase, frequency, and magnitude of V1g coincide with V1s, the first main circuit breaker 8 is turned on to parallel the I machine 100 with the system I. When the first excitation control device 5 in parallel controls the rotation speed to be constant and the output of the second excitation converter 14 is reduced to reduce the winding current of the stator 12 to zero, the second disconnection is performed. Open the vessel 13. At the same time, the second excitation control device 15 inputs the terminal voltage V2g of the II machine 200 and the voltage V2s of the second system II from the voltage measuring device 19 so that the phase, frequency and magnitude of V2g coincide with V2s. The output of the second excitation converter 14 is controlled. When the phase, frequency, and magnitude of V2g coincide with V2s, the second main circuit breaker 18 of the II machine 200 is turned on to parallel the II machine 200 with the second system II. Conversely, in the same procedure, the I machine 100 and the II machine 200 can be started simultaneously by exciting the I machine 100 and the II machine 200, and the II machine 200 can be paralleled with the second system II first. In other words, the third embodiment is a method of starting and accelerating simultaneously using two variable speed generator motors without increasing the excitation device, and is advantageous in that it can be accelerated to the rated speed without increasing the excitation device capacity. There is.
[0015]
Embodiment 4 FIG.
The configuration of the variable speed frequency converter according to the fourth embodiment of the present invention is shown in FIG. In the figure, a first variable speed generator-motor I machine 100 and a second variable-speed generator motor II machine 200 are connected coaxially, and the respective stator windings 2 and 12 are connected to the first main circuit breaker 8 and the second The main circuit breaker 18 is connected to the first system I and the second system II, and the respective rotor windings 1 and 11 are connected to the secondary side of the first and second excitation converters 4 and 14. Connecting. The primary sides of the first and second excitation converters 4 and 14 are connected to the secondary sides of the excitation transformers 7 and 17, respectively, and the control input side is connected to the first and second excitation control devices 5 and 15. The primary sides of the excitation transformers 7 and 17 are connected to the first system I and the second system II via the first and second excitation circuit breakers 6 and 16. The output sides of the first and second excitation converters 4 and 14 are connected to the rotors 1 and 11 via the first and second field breakers 20 and 21, and the secondary side is connected. They are connected via a third field breaker 22 for parallel connection. Reference numeral 10 denotes a sensor for measuring the rotational speed of the generator motor. Reference numerals 9 and 19 denote terminal voltages V1g and V2g of the I machine 100 and II machine 200, and a voltage V1s of the first system I and the second system II, respectively. This is a voltage measuring device for measuring V2s.
[0016]
Next, the operation of the apparatus will be described. In the state where the rotational speed of the generator motor is zero, the first and second disconnectors 3 and 13 of the I machine 100 and the II machine 200, the first and second main circuit breakers 8 and 18, the first and second The three-phase windings of the stator 2 of the I machine 100 are shortened by the first disconnector 3. The first and third field breakers 20 and 22 are turned on, and the first excitation converter 4 and the second excitation converter 14 are arranged in parallel. Then, the first and second excitation breakers 6 and 16 are turned on, and the three-phase excitation voltage is generated by the first excitation converter 4 and the second excitation converter 14 in parallel with the rotor windings 1 and 11. The rotors of the I machine 100 and the II machine 200 are simultaneously rotated by the torque generated by the crossing of the rotating magnetic field of the rotor and the stator coil. Further, the first and second excitation control devices 5 and 15 receive the rotational speed signal ωr from the rotational speed sensor 10 to increase the frequency of the output voltage of the first and second excitation converters 4 and 14. To accelerate the rotation speed. When the rotational speed exceeds a predetermined value, the second excitation converter 14 is stopped, the third field breaker 22 is opened, the second field breaker 21 is turned on, and the second excitation converter 14 is turned on. The normal excitation is applied to the winding of the rotor 11. While the first excitation control device 5 controls the rotation speed to be constant, the second excitation control device 15 inputs the terminal voltage V2g of the II machine 200 and the voltage V2s of the second system II from the voltage measurement device 19. The output of the second excitation converter 14 is controlled so that the phase, frequency and magnitude of V2g coincide with those of V2s. When the phase, frequency, and magnitude of V2g coincide with V2s, the second main circuit breaker 18 is turned on to make the II machine 200 parallel to the second system II. The second excitation control device 15 inputs the rotational speed signal ωr from the rotational speed measuring sensor 10 at the same time, and controls the output of the second excitation converter 14 so that the rotational speed becomes constant. When the excitation converter 4 demagnetizes the excitation output to reduce the winding current of the stator 2 to near zero, the first disconnector 3 is opened, and the first excitation converter 4 is connected to the rotor 1. Apply normal excitation and control the phase, frequency and magnitude of V1g to match V1s by the terminal voltage V1g of I machine 100 measured from the voltage measuring device 9 and the voltage V1s of the first system I. To do. When the phase, frequency, and magnitude of V1g coincide with V1s, the first main circuit breaker 8 of the I machine 100 is turned on to parallel the I machine 100 with the first system I.
Conversely, in the same procedure, the I machine 100 and the II machine 200 are started by applying excitation to the II machine 200 in parallel with the excitation converters 4 and 14 of the I machine 100 and the II machine 200, When the rotation speed is accelerated to a predetermined value, the first excitation converter 4 is inserted into the I machine 100, and the I machine 100 is first paralleled with the first system I and then the II machine 200 is installed in the second system. It can also be parallel to II. In other words, the fourth embodiment has a circuit configuration in which two excitation devices are arranged in parallel before starting to provide excitation to one variable speed generator-motor, and acceleration is performed by one device, and one excitation device is disconnected during parallel operation. This is a method in which the original excitation is applied and synchronous parallel is performed on the stator side.
[0017]
Embodiment 5. FIG.
FIG. 4 shows the configuration of the variable speed frequency converter according to the fifth embodiment of the present invention. In the figure, a first variable speed generator-motor I machine 100 and a second variable-speed generator motor II machine 200 are connected coaxially, and the respective stator windings 2 and 12 are connected to the first main circuit breaker 8 and the second Connected to the first system I and the second system II via the main circuit breaker 18, and the respective rotor windings 1 and 11 are connected to the secondary side of the first and second excitation converters 4 and 14. To do. The primary sides of the first and second excitation converters 4 and 14 are connected to the secondary sides of the excitation transformers 7 and 17, respectively, and the control input side is connected to the first and second excitation control devices 5 and 15. The primary sides of the excitation transformers 7 and 17 are connected to the first system I and the second system II via the first and second excitation circuit breakers 6 and 16, respectively. The output sides of the first and second excitation converters 4 and 14 are connected to the rotors 1 and 11 via the first and second field breakers 20 and 21, and the secondary side is connected. It connects via the 3rd field breaker 22 for paralleling. 10 is a sensor for measuring the rotational speed of the generator motor, 9 is a voltage measuring device for measuring the terminal voltage V1g of the I machine 100 and the voltage V1s of the system I, and 19 is the voltage of the second rotor. This is a voltage measuring device for measuring V2r and the voltage V2e of the output of the second excitation converter 14.
[0018]
Next, the operation of the apparatus will be described. When the rotational speed of the generator motor is zero, the first and second disconnectors 3 and 13 of the I machine 100 and the II machine 200, the first and second main circuit breakers 8 and 18, the first and second The three-phase windings of the stator 2 of the I machine 100 are short-circuited by the first disconnector 3. The first and third field breakers 20 and 22 are turned on, and the first excitation converter 4 and the second excitation converter 14 are arranged in parallel. Then, the first and second excitation breakers 6 and 16 are turned on, and a three-phase excitation voltage is generated by the first excitation converter 4 and the second excitation converter 14 in parallel with the rotor windings 1 and 11. The rotors of the I machine 100 and the II machine 200 are simultaneously rotated by the torque generated by the crossing of the rotating magnetic field of the rotor and the stator coil. Further, the first and second excitation control devices 5 and 15 receive the rotation speed signal ωr from the rotation speed sensor 10 and increase the frequency of the output voltage of the first excitation converter 5 to accelerate the rotation speed. To do. When the rotation speed exceeds a predetermined value, the second excitation converter 14 is stopped, the third field breaker 22 is opened, the second main circuit breaker 18 of the II machine 200 is turned on, and the II machine 200 In parallel with the second system II.
Then, the second excitation control device 15 inputs the voltage V2r of the second rotor 11 and the voltage V2e of the second excitation converter 14 measured by the voltage measuring device 19, and the phase, frequency and magnitude of V2e are input. The output of the second excitation converter 14 is controlled so as to coincide with V2r. When the phase, frequency, and magnitude of V2e coincide with V2r, the second field breaker 21 is turned on and normal excitation is applied to the winding of the rotor 11 of the II machine 200. However, in this case, the voltage V2r of the rotor 11 input to the second voltage measuring device 19 is switched to the voltage V2s of the system II.
The second excitation control device 15 inputs the rotation speed signal from the rotation speed measuring sensor at the same time, and controls the output of the second excitation converter 14 so that the rotation speed becomes constant, while the first excitation conversion is performed. When the generator 4 demagnetizes the excitation output to reduce the winding current of the stator 2 to near zero, the first disconnector 3 is opened, and the first excitation converter 4 is normally excited in the rotor 1. And the phase, frequency, and magnitude of V1g are controlled to match V1s by the terminal voltage V1g of the I machine 100 measured from the voltage measuring device 9 and the voltage V1s of the system I. When the phase, frequency, and magnitude of V1g coincide with V1s, the first main circuit breaker 8 of the I machine 100 is turned on to parallel the I machine 100 with the first system I.
Conversely, in the same procedure, the excitation converters 4 and 14 of the I machine 100 and the II machine 200 are arranged in parallel to apply excitation to the II machine 200, thereby starting the I machine 100 and the II machine 200 and rotating them. If the speed is accelerated to a predetermined value, the I machine 100 can be paralleled with the first system I first, and then the II machine 200 can be paralleled with the second system II. However, in this case, the winding voltage of the rotor 1 and the output voltage of the first excitation converter 4 are input to the voltage measuring device 9 of the first excitation control device 5 of the I machine 100, and the second voltage of the II machine 200 is inputted. The voltage measurement device 19 of the excitation control device 15 receives the terminal voltage of the II machine 200 and the second system II voltage. That is, the difference between the fifth embodiment and the fourth embodiment is that the variable speed generator motors that are paralleled first are paralleled on the excitation side.
In the first to fifth embodiments described above, circuit breakers may be used for the first and second disconnectors 3 and 13.
[0019]
【The invention's effect】
Since the present invention employs the starting method as described above, the following effects can be obtained.
[0020]
One of the two directly connected variable speed generator motors is started first, the remaining one is first connected in parallel to the power system, and then the previous one used for starting is used in parallel. Therefore, there is no occurrence of a case that falls below the lower limit of the variable speed range of the exciter, and there is an advantage that power can be interchanged between different systems easily and smoothly with an inexpensive device.
[0021]
In addition, one of the two directly connected variable speed generator motors is started first, and the other one is de-energized and the second main circuit breaker is turned on in parallel with the power system. Therefore, the same effect as described above can be obtained.
[0022]
Furthermore, since the two variable speed generator motors are started and accelerated simultaneously, there is no need to increase the capacity of the excitation device, and it is fully compatible with cases where acceleration to the rated speed is not possible due to insufficient acceleration torque. The effect is possible.
[0023]
Further, since the two excitation devices are arranged in parallel before the start of starting, and excitation is performed on one variable speed generator-motor, the same effects as described above can be obtained.
[0024]
Furthermore, since the variable speed generator motors that are first paralleled to the system are paralleled on the excitation side, the same effects as described above can be obtained.
[Brief description of the drawings]
FIG. 1 is a diagram showing a configuration of a variable speed frequency converter according to a first embodiment of the present invention.
FIG. 2 is a diagram showing a configuration of a variable speed frequency converter according to a second embodiment of the present invention.
FIG. 3 is a diagram showing a configuration of a variable speed frequency converter according to a fourth embodiment of the present invention.
FIG. 4 is a diagram showing a configuration of a variable speed frequency converter according to a fifth embodiment of the present invention.
[Explanation of symbols]
1,11 rotor, 2,12 stator, 3 first disconnector,
4 first excitation converter, 5 first excitation control device, 6 first excitation circuit breaker,
7, 17 excitation transformer, 8 first main circuit breaker, 9, 19 voltage measuring device,
10 sensor, 13 second disconnector, 14 second excitation transducer,
15 Second excitation control device, 16 Second excitation circuit breaker, 18 Second main circuit breaker,
20 first field breaker, 21 second field breaker, 22 third field breaker,
100 1st variable speed generator motor, 200 2nd variable speed generator motor.

Claims

The rotor is composed of first and second variable speed generator-motors that are directly and coaxially connected to each other and connected to the first power system and the second power system, respectively, and includes the following steps: The starting method of the shift frequency converter.
(1) A step of exciting the first variable speed generator-motor and setting the rotation speed to a predetermined value or higher together with the rotor of the second variable-speed generator motor.
(2) A step of demagnetizing the first variable speed generator-motor after exciting the second variable-speed generator motor and paralleling the second variable speed generator-motor to the second power system.
(3) Next, exciting the first variable speed generator motor and paralleling it to the first power system.

The rotor is composed of first and second variable speed generator-motors that are directly and coaxially connected to each other and connected to the first power system and the second power system, respectively, and includes the following steps: The starting method of the shift frequency converter.
(1) A step of demagnetizing the second variable speed generator-motor after exciting the first and second variable-speed generator motors to a rotational speed equal to or higher than a predetermined value.
(2) A step of demagnetizing the first variable speed generator-motor after exciting the second variable-speed generator motor and paralleling the second variable speed generator-motor to the second power system.
(3) Next, exciting the first variable speed generator motor and paralleling it to the first power system.

The rotor is composed of first and second variable speed generator-motors that are directly and coaxially connected to each other and connected to the first power system and the second power system, respectively, and includes the following steps: The starting method of the shift frequency converter.
(1) A stator winding of a first variable speed generator-motor is short-circuited by a first disconnector, an excitation voltage is applied to the rotor by a first excitation converter, and the first variable-speed generator-motor is And rotating the rotor of the second variable speed generator-motor directly connected thereto.
(2) A step of controlling the rotation speed by controlling the frequency of the excitation power source with the first excitation control device so that the rotation speed is a predetermined value or more.
(3) A second excitation converter is inserted into the rotor of the second variable speed generator motor to apply and control normal excitation, and the phase, frequency and magnitude of the stator side voltage are scheduled to be paralleled. Matching with the power grid of
(4) A step of turning on the second main circuit breaker and paralleling with the second power system.
(5) A step of reducing the stator current to near zero by demagnetizing the rotor excitation of the first variable speed generator motor while controlling the rotation speed of the second variable speed generator motor to be constant.
(6) Open the first disconnector to open the short circuit of the stator winding of the first variable speed generator motor, and apply and control the normal excitation to the rotor to control the phase, the frequency of the stator side voltage, Matching the magnitude to the first power system scheduled in parallel.
(7) A step of paralleling the first variable speed generator-motor to the first power system by turning on the first main circuit breaker and paralleling the first power breaker.

The rotor is composed of first and second variable speed generator-motors that are directly and coaxially connected to each other and connected to the first power system and the second power system, respectively, and includes the following steps: The starting method of the shift frequency converter.
(1) A stator winding of a first variable speed generator-motor is short-circuited by a first disconnector, an excitation voltage is applied to the rotor by a first excitation converter, and the first variable-speed generator-motor is And rotating the rotor of the second variable speed generator-motor directly connected thereto.
(2) A step of controlling the rotation speed by controlling the frequency of the excitation power source with the first excitation control device so that the rotation speed is a predetermined value or more.
(3) A step of turning on the second main circuit breaker provided in the stator of the second variable speed generator motor and paralleling the second main circuit breaker.
(4) The second excitation control device inputs the second rotor voltage and the output voltage of the second excitation converter, and the phase, frequency and magnitude of the output voltage coincide with the second rotor voltage. After the control, the second field breaker is turned on to apply normal excitation to the rotor.
(5) A step of reducing the stator current to near zero by demagnetizing the rotor excitation of the first variable speed generator motor while controlling the rotation speed of the second variable speed generator motor to be constant.
(6) Open the first disconnector to open the short circuit of the stator winding of the first variable speed generator motor, and apply and control the normal excitation to the rotor to control the phase, the frequency of the stator side voltage, Matching the magnitude to the first power system scheduled in parallel.
(7) A step of paralleling the first variable speed generator-motor to the first power system by turning on the first main circuit breaker and paralleling the first power breaker.

The rotor is composed of first and second variable speed generator-motors that are directly and coaxially connected to each other and connected to the first power system and the second power system, respectively, and includes the following steps: The starting method of the shift frequency converter.
(1) The stator windings of the first and second variable speed generator motors are short-circuited by the first and second disconnectors, and the excitation voltages are applied to the respective rotors by the first and second excitation converters. And rotating the rotors of the first and second variable speed generator-motors.
(2) A step of controlling the rotation speed by controlling the frequency of the excitation power source applied to each rotor by the first and second excitation control devices, so that the rotation speed is equal to or higher than a predetermined value.
(3) The step of reducing the stator current to near zero by demagnetizing the rotor excitation of the second variable speed generator motor while controlling the rotation speed of the first variable speed generator motor to be constant.
(4) Open the second disconnector to open the short circuit of the stator winding of the second variable speed generator motor, and apply and control the normal excitation to the rotor to control the phase, the frequency of the stator side voltage, Matching the magnitude to the second power system scheduled for parallel.
(5) A step of turning on the second main circuit breaker and paralleling with the second power system.
(6) A step of reducing the stator current to near zero by demagnetizing the rotor excitation of the first variable speed generator motor while controlling the rotation speed of the second variable speed generator motor to be constant.
(7) Open the first disconnector to open the short circuit of the stator winding of the first variable speed generator motor, and apply and control the normal excitation to the rotor to control the phase, frequency of the stator side voltage, Matching the magnitude to the first power system scheduled in parallel.
(8) A step of paralleling the first variable speed generator-motor to the first power system by turning on a first main circuit breaker and paralleling the first power breaker.

The rotor is composed of first and second variable speed generator-motors that are directly and coaxially connected to each other and connected to the first power system and the second power system, respectively, and includes the following steps: The starting method of the shift frequency converter.
(1) The stator winding of the first variable speed generator-motor is short-circuited by the first disconnector, and the first and second variable-speed generator motors are paralleled with the first and second excitation converters. Applying excitation voltage to the rotor to rotate the rotor of the first and second variable speed generator motors;
(2) A step of controlling the rotation speed by controlling the frequency of the excitation power source with the first and second excitation control devices so that the rotation speed is equal to or higher than a predetermined value.
(3) The second excitation converter is disconnected from the parallel with the first excitation converter, and normal excitation is applied to and controlled by the rotor of the second variable speed generator motor to Matching the phase, frequency, and magnitude with the second power system scheduled in parallel;
(4) A step of turning on the second main circuit breaker and paralleling with the second power system.
(5) A step of reducing the stator current to near zero by demagnetizing the rotor excitation of the first variable speed generator motor while controlling the rotation speed of the second variable speed generator motor to be constant.
(6) Open the first disconnector to open the short circuit of the stator winding of the first variable speed generator motor, and apply and control the normal excitation to the rotor to control the phase, the frequency of the stator side voltage, Matching the magnitude to the first power system scheduled in parallel.
(7) A step of paralleling the first variable speed generator-motor to the first power system by turning on the first main circuit breaker and paralleling the first power breaker.

The rotor is composed of first and second variable speed generator-motors that are directly and coaxially connected to each other and connected to the first power system and the second power system, respectively, and includes the following steps: The starting method of the shift frequency converter.
(1) A stator winding of the first variable speed generator-motor is short-circuited by a first disconnector, and the first and second excitation converters are arranged in parallel, and the first and second variable-speed generator motors Applying an excitation voltage to the first rotor and rotating the rotor of the first and second variable speed generator-motors.
(2) A step of controlling the rotation speed by controlling the frequency of the excitation power source with the first and second excitation control devices so that the rotation speed is equal to or higher than a predetermined value.
(3) The second excitation converter is disconnected from the parallel with the first excitation converter, the second main circuit breaker is turned on, and the second variable speed generator motor is connected in parallel with the second power system. Step to do.
(4) The second excitation control device inputs the voltage of the second rotor and the output voltage of the second excitation converter, and sets the phase, frequency and magnitude of the output voltage to the second rotor voltage. Controlling to match.
(5) Applying normal excitation to the rotor of the second variable speed generator-motor and demagnetizing the rotor excitation of the first variable-speed generator motor while controlling the rotation speed to be constant. Reducing the current to near zero.
(6) Open the first disconnector to open the short circuit of the stator winding of the first variable speed generator motor, and apply and control the normal excitation to the rotor to control the phase, the frequency of the stator side voltage, Matching the magnitude to the first power system scheduled in parallel.
(7) A step of paralleling the first variable speed generator-motor to the first power system by turning on the first main circuit breaker and paralleling the first power breaker.