JP4037967B2

JP4037967B2 - Distribution line voltage adjustment method and apparatus

Info

Publication number: JP4037967B2
Application number: JP27761698A
Authority: JP
Inventors: 忠士栗山
Original assignee: Daihen Corp
Current assignee: Daihen Corp
Priority date: 1998-09-30
Filing date: 1998-09-30
Publication date: 2008-01-23
Anticipated expiration: 2018-09-30
Also published as: JP2000116006A

Description

【０００１】
【発明の属する技術分野】
本発明は、３相配電線の線間に現れる３相の電圧の不平衡状態を是正するための電圧調整を行う電圧調整方法及び該電圧調整方法を実施するために用いる電圧調整装置に関するものである。
【０００２】
【従来の技術】
配電線の電圧を調整する電圧調整装置として、図５に示したものが用いられている。図５において、Ｔ１はタップ１〜９を備えた直列巻線Ｗa1と分路巻線Ｗb1とを有する第１の単巻変圧器、Ｔ２は同じくタップ１〜９を有する直列巻線Ｗa2と分路巻線Ｗb2とを有する第２の単巻変圧器である。これらの単巻変圧器はそれぞれの分路巻線側の端部を共通に接続することによりＶ結線されて、単巻変圧器Ｔ１及びＴ２の分路巻線側の端部の共通接続点からＶ相の一次及び二次共通端子ｔv が導出され、単巻変圧器Ｔ１及びＴ２のそれぞれのタップを選択する負荷時タップ切換器のタップ選択器ＴＣ１及びＴＣ２からそれぞれｕ相及びｗ相の一次端子ｔu1及びｔw1が導出されている。また単巻変圧器Ｔ１及びＴ２のそれぞれの素通しタップからｕ相及びｗ相の二次端子ｔu2及びｔw2が導出されている。ＣＴはｕ相及びｗ相の二次電流を検出する変流器、Ｗc1及びＷc2はそれぞれ単巻変圧器Ｔ１及びＴ２に設けられた制御巻線で、制御巻線Ｗc1及びＷc2は互いに直列に接続されて、負荷時タップ切換器を制御する図示しない制御装置に電圧検出信号を与える電圧検出用巻線及び該制御装置の電源用巻線として用いられる。
【０００３】
負荷時タップ切換器は、負荷側の配電線の電圧に応じてタップ選択器ＴＣ１及びＴＣ２の切換動作を同時に行わせて、２台の単相変圧器Ｔ１及びＴ２の同じ電圧のタップを選択することにより、負荷側の配電線の電圧を調整する。
【０００４】
【発明が解決しようとする課題】
３相配電線の線間に現れる３相の電圧は必ずしも平衡しておらず、３相の線路電流に不平衡が生じると線間電圧にも不平衡が生じるのを避けられない。３相の電圧の不平衡がひどくなると、需要家に到達する電圧が規定値を下回って需要家の機器に悪影響を与えるおそれがある。従って、３相の電圧を平衡状態に近付けるように線間電圧の大きさと位相とを調整することが望ましいが、従来の電圧調整器では、常に２台の変圧器のタップを同一電圧タップに切り換えて３相の電圧を同時に調整していたため、上記３相の電圧が不平衡であると、電圧調整装置から出力される３相の電圧も同じ割合で平衡が崩れた不平衡電圧となり、不平衡電圧を平衡電圧に是正する機能を持たせることができなかった。
【０００５】
本発明の目的は、３相配電線の線間に現れる３相の電圧が不平衡であるときに、該不平衡電圧を是正するための調整を行う電圧調整方法及び該電圧調整方法を実施するために用いる電圧調整装置を提供することにある。
【０００６】
【課題を解決するための手段】
本発明の電圧調整方法では、３相配電線の線間に現れる３相の電圧のうちの２相の電圧の大きさをそれぞれ独立に調整し得るように２台のタップ付の単相電圧調整器を設けておき、３相の電圧のうちの残る１相の電圧を基準電圧として前記２相の電圧のうちの一方の大きさを基準電圧に近付けるように２台の単相電圧調整器のうちの一方のタップを切り換える過程、及び２相の電圧のうちの他方の大きさを前記基準電圧の大きさに近付けるように２台の単相電圧調整器のうちの他方のタップを切り換える過程の一方または双方を、２相の電圧の双方の大きさが前記基準電圧の大きさにほぼ等しくなるまで行うことにより、３相の電圧を平衡させる。
【０００７】
上記のように、上記１相の電圧を基準電圧として上記２相の電圧うちの一方の大きさを基準電圧の大きさに近付けるようにタップを切り換える過程、及び上記２相の電圧のうちの他方の大きさを基準電圧の大きさに近付けるようにタップを切り換える過程の一方または双方を行って３相の電圧を平衡させるようにすると、３相の電圧を平衡させるために必要なタップ位置を求めるための複雑な演算を行うことなく、タップ切り換えを行うことができるため、タップ切換装置の構成を簡単にすることができる。
【０００８】
なお本明細書において、「２相の電圧の双方の大きさを基準電圧の大きさにほぼ等しくする」とは、それぞれの相の電圧の大きさと基準電圧の大きさとの差を予め定めた許容範囲以下にすること（当然それぞれの相の電圧の大きさと基準電圧の大きさとの差を零にすることを含む。）を意味する。即ち、上記２相の電圧のそれぞれの大きさを基準電圧の大きさにほぼ等しく調整する際には、ある程度の誤差を伴うことを許容するものとする。
【０００９】
上記のように、３相の電圧のうちの２相の電圧の大きさをそれぞれ独立に調整し得るように電圧調整器を設けて、上記１相の電圧を基準電圧として上記２相の電圧の双方の大きさを基準電圧の大きさにほぼ等しくするように電圧調整を行うようにすると、線間電圧が不平衡３相電圧である場合に、その不平衡を是正して電圧調整装置よりも負荷側の配電線に送り出すことができるため、配電線の３相電圧の不平衡状態を改善することができる。また配電線電圧の不平衡状態を改善すると、線間電圧の大きさを電圧管理幅内に収めるための電圧調整（従来の電圧調整器を用いて行うことができる）を容易に行うことができるため、需要家に高品質の電力を供給することができる。
【００１０】
上記本発明の方法を実施する電圧調整装置は、３相配電線の線間電圧のうちの上記１相の電圧の大きさを一定とした状態で上記２相の電圧の大きさをそれぞれ独立に調整し得るように結線された第１及び第２のタップ付の単相電圧調整器と、上記１相の電圧を基準電圧として上記２相の電圧の双方の大きさを基準電圧の大きさにほぼ等しくするように第１の電圧調整器及び第２の電圧調整器のタップを切り換えるタップ切換装置とを備えることにより構成できる。
【００１１】
上記タップ切換装置は、上記１相の電圧を基準電圧として上記２相の電圧のうちの一方の大きさを基準電圧の大きさに近付けるように第１の電圧調整器のタップを切り換えるタップ切換動作、及び上記２相の電圧のうちの他方の大きさを基準電圧の大きさに近付けるように第２の単相電圧調整器のタップを切り換えるタップ切換動作の一方または双方を、上記２相の電圧の双方の大きさが基準電圧の大きさにほぼ等しくなるまで行うように構成することができる。
【００１２】
本発明の好ましい態様では、直列巻線にタップが設けられた第１の単巻変圧器と該第１の単巻変圧器のタップを選択する第１のタップ選択器とを備えた第１の単相電圧調整器と、直列巻線にタップが設けられた第２の単巻変圧器と該第２の単巻変圧器のタップを選択する第２のタップ選択器とを備えた第２の単相電圧調整器と、第１及び第２の単相電圧調整器のタップをそれぞれ個別に切り換えるタップ切換装置とを設けて、第１の単巻変圧器の素通しタップを第２のタップ選択器に接続し、第１の単巻変圧器の分路巻線側の端部から３相のうちの１相の一次及び二次端子を導出する。また第２の単巻変圧器の分路巻線側の端部から他の１相の一次及び二次端子を導出し、第１のタップ選択器及び第２の単巻変圧器の素通しタップからそれぞれ残りの１相の一次端子及び二次端子を導出する。この場合、タップ切換装置は、第１の単巻変圧器及び第２の単巻変圧器の分路巻線側の端部からそれぞれ導出された二次端子間に現れる１相の電圧を基準電圧として他の２相の電圧の双方の大きさを基準電圧の大きさに近付けるように第１の単相電圧調整器及び第２の単相電圧調整器のタップを切り換えるように構成する。
【００１３】
この場合も、タップ切換装置は、第１の単巻変圧器及び第２の単巻変圧器の分路巻線側の端部からそれぞれ導出された端子間に現れる１相の電圧を基準電圧として他の２相の電圧のうちの一方の大きさを基準電圧の大きさに近付けるように第１の単相電圧調整器のタップを切り換えるタップ切換動作、及び他の２相の電圧のうちの他方の大きさを基準電圧の大きさに近付けるように第２の単相電圧調整器のタップを切り換えるタップ切換動作の一方または双方を、他の２相の電圧の双方の大きさが基準電圧の大きさにほぼ等しくなるまで行うように構成することができる。
【００１４】
【発明の実施の形態】
図１は本発明に係わる電圧調整方法を実施するために用いる電圧調整装置の構成例を示した結線図で、同図において、Ｔ１はタップ１〜７を備えた直列巻線Ｗa1と分路巻線Ｗb1とを有する第１の単巻変圧器、Ｔ２は同じくタップ１〜７を有する直列巻線Ｗa2と分路巻線Ｗb2とを有する第２の単巻変圧器である。またＴＣ１及びＴＣ２はそれぞれ第１及び第２の単巻変圧器Ｔ１及びＴ２のタップを選択する第１及第２のタップ選択器で、第１の単巻変圧器Ｔ１と第１のタップ選択器ＴＣ１とにより第１の単相電圧調整器１１が構成され、第２の単巻変圧器Ｔ２と第２のタップ選択器ＴＣ２とにより第２の単相電圧調整器１２が構成されている。また図示してないが、第１及び第２の単相電圧調整器１１及び１２のタップをそれぞれ個別に切り換えるタップ切換装置が設けられている。
【００１５】
図１の例では、第１の単巻変圧器Ｔ１及び第２の単巻変圧器Ｔ２のそれぞれのタップ４が素通しタップとなっていて、第１の単巻変圧器Ｔ１の素通しタップ４が第２のタップ選択器ＴＣ２に接続されている。そして、第１の単巻変圧器Ｔ１の分路巻線Ｗa1側の端部から３相のうちの１相（図示の例ではＵ相）の一次端子ｔu1及び二次端子ｔu2が導出され、第２の単巻変圧器Ｔ２の分路巻線Ｗb2側の端部から他の１相（図示の例ではＷ相）の一次端子ｔw1及び二次端子ｔw2が導出されている。また第１のタップ選択器ＴＣ１及び第２の単巻変圧器Ｔ２の素通しタップ４からそれぞれ残りの１相の一次端子ｔv1及び二次端子ｔv2が導出されている。
【００１６】
このように２台の単相電圧調整器１１及び１２を結線すると、第１の単巻変圧器Ｔ１及び第２の単巻変圧器Ｔ２の分路巻線Ｗb1及びＷb2側の端部からそれぞれ導出された二次端子ｔu2，ｔw2間に現れる１相の電圧ＶB を一定に保った状態で、二次端子ｔu2，ｔv2間及びｔv2，ｔw2間に現れる他の２相の電圧Ｖ1 及びＶ2 をそれぞれ個別に調整することができる。
【００１７】
図示しないタップ切換装置は、第１の単巻変圧器Ｔ１及び第２の単巻変圧器Ｔ２の分路巻線Ｗb1及びＷb2側の端部からそれぞれ導出された二次端子ｔu2，ｔw2間（ｕ，ｗ相間）に現れる１相の電圧を基準電圧ＶB として他の２相の電圧Ｖ1 ，Ｖ2 のうちの一方の大きさを基準電圧の大きさに近付けるように第１の単相電圧調整器１１のタップを切り換えるタップ切換動作と、他の２相の電圧のうちの他方の大きさを基準電圧ＶB の大きさに近付けるように第２の単相電圧調整器１２のタップを切り換えるタップ切換動作とを行うことができるように構成されていて、これらのタップ切換動作の一方または双方を、他の２相の電圧の双方の大きさが基準電圧の大きさにほぼ等しくなるまで行うことにより、３相の電圧を平衡させるようになっている。
【００１８】
図２は、図１の電圧調整装置を用いて３相電圧の不平衡を是正する際のタップ切換動作を示したベクトル図である。
【００１９】
最初二次端子ｔu2，ｔv2間（ｕ，ｖ相間）の電圧Ｖ1 のベクトルとｔv2，ｔw2（ｖ，ｗ相間）間の電圧Ｖ2 のベクトルの交点が図示のａ点にあって３相が不平衡な状態にあったとする。このとき先ずｕ，ｖ相間の電圧Ｖ1 の大きさを基準電圧ＶB の大きさに近付ける側に変化させるように第１のタップ選択器ＴＣ１が選択するタップを１タップ切り換える。これにより調整電圧ΔＶ11を発生させてｕ，ｖ相間の電圧Ｖ1 のベクトルとｖ，ｗ相間の電圧Ｖ2 のベクトルとの交点をｂ点に移動させる。次いで、ｖ，ｗ相間の電圧の大きさを基準電圧ＶB の大きさに近付けるように第２のタップ選択器ＴＣ２が選択するタップを１タップ切り換えることにより調整電圧ΔＶ21を発生させて、電圧Ｖ1 及びＶ2 のベクトルの交点をｃ点に移動させる。次にｕ，ｖ相間の電圧Ｖ1 の大きさを基準電圧ＶB の大きさに近付けるように第１のタップ選択器ＴＣ１が選択するタップを１タップ切り換えることにより、調整電圧ΔＶ12を発生させて電圧Ｖ1 及びＶ2 のベクトルの交点をｄ点に移動させる。以下同様のタップ切換動作を繰り返して調整電圧ΔＶ22，ΔＶ13，ΔＶ23を順次発生させることにより電圧Ｖ1 及びＶ2 のベクトルの交点をｅ点、ｆ点を経てｇ点まで移動させて、二次端子ｔu2，ｔv2，ｔw2から平衡した３相電圧を出力させる。
【００２０】
図３は、２台の単巻変圧器のそれぞれのタップ数が７である場合に平衡に調整し得る不平衡電圧の範囲を示したものであり、電圧Ｖ1 及びＶ2 のベクトルの交点が図３の破線群の交点のいずれかである場合には、上記のように単巻変圧器Ｔ１及びＴ２のタップ切り換えを交互に行うことにより、不平衡電圧を平衡電圧に変換することができる。なお不平衡電圧を平衡電圧に変換する際のタップ切り換えは、必ずしも２台の電圧調整器のタップ切り換えを交互に行う必要はなく、例えば電圧Ｖ１及びＶ２のベクトルの交点が図３のＰ1 〜Ｐ4 のいずれかである場合には、電圧調整器１１または１２のいずれか一方のタップ切り換えを行うだけで不平衡電圧を平衡電圧に変換することができる。
【００２１】
図４は、タップ切換装置に上記のタップ切換動作を行わせる場合に、マイクロコンピュータに実行させるプログラムのアルゴリズムの一例を示したもので、このアルゴリズムに従う場合には、先ずステップ１でｕ，ｖ相間の電圧Ｖ1 とｕ，ｗ相間の基準電圧ＶB とを比較して、Ｖ1 ＞ＶB である場合には、ステップ２に移行して第１のタップ選択器ＴＣ１を１タップ降圧側に切り換える。ステップ１において、Ｖ1 ＜ＶB と判定された場合には、ステップ３に移行して、第１のタップ選択器ＴＣ1 を１タップ昇圧側に切り換える。ステップ２が終了したとき、ステップ３が終了したとき、及びステップ１においてＶ1 ＝ＶB である（Ｖ1 とＶB とがほぼ等しい）と判定されたときには、次いでステップ４に移行してｖ，ｗ相間の電圧Ｖ2 とｕ，ｗ相間の基準電圧ＶB とを比較して、Ｖ2 ＞ＶB である場合には、ステップ５に移行して第２のタップ選択器ＴＣ２を１タップ降圧側に切り換える。ステップ４において、Ｖ2 ＜ＶB と判定された場合には、ステップ６に移行して、第２のタップ選択器ＴＣ２を１タップ昇圧側に切り換える。ステップ５が終了したとき、ステップ６が終了したとき、及びステップ４においてＶ21＝ＶB である（Ｖ2 とＶB とがほぼ等しい）と判定されたときには、ステップ１に戻って上記の過程を繰り返す。
【００２２】
上記の例では、２台の電圧調整器のタップ切換を交互に行うことにより最終的に２相の電圧を基準電圧とした１相の電圧にほぼ等しくするようにしたが、これはタップの切り換え方の一例を示したものである。本発明においては、１相の電圧を基準電圧として他の２相の電圧を調整することにより、不平衡電圧を平衡電圧に変換するようにすればよく、２台の電圧調整器のタップの切り換え方は上記の例に限定されない。例えば、２相の電圧を調整する２台の電圧調整器のタップ切り換えにより影響を受けない１相の電圧を基準にして、３相平衡電圧を出力するために必要な残りの２相の電圧調整器のタップ位置を演算により求めて、２台の電圧調整器のタップをそれぞれ求められたタップに切り換えるようにしてもよい。
【００２３】
上記の例では、２台の電圧調整器として単巻変圧器を電圧調整用変圧器として用いたものを使用したが、本発明で用いることができる電圧調整用変圧器は単巻変圧器に限定されるものではない。
【００２４】
【発明の効果】
以上のように、本発明によれば、３相配電線の線間に現れる３相の電圧のうちの２相の電圧の大きさをそれぞれ独立に調整し得るように電圧調整器を設けて、３相の電圧のうちの残る１相の電圧を基準電圧として上記２相の電圧の大きさを基準電圧の大きさにほぼ等しくするように電圧調整を行うようにしたので、配電線の線間電圧が不平衡３相電圧である場合に、電圧調整器よりも負荷側の配電線でその不平衡を是正することができる利点がある。
【図面の簡単な説明】
【図１】本発明に係わる電圧調整装置の要部の構成例を示した結線図である。
【図２】図１の電圧調整装置の調整動作の一例を示したベクトル図である。
【図３】図１の電圧調整装置により３相不平衡電圧を平衡電圧に調整する場合の調整可能範囲を示したベクトル図である。
【図４】図１の電圧調整装置のタップ切換装置の制御アルゴリズムの一例を示したフローチャートである。
【図５】従来の電圧調整装置の構成例を示した接続図である。
【符号の説明】
１１第１の単相電圧調整器
１２第２の単相電圧調整器
Ｔ１第１の単巻変圧器
ＴＣ１第１のタップ選択器
Ｔ２第２の単巻変圧器
ＴＣ２第２のタップ選択器
ｔu1，ｔv1，ｔw1 一次端子
ｔu2，ｔv2，ｔw2 二次端子[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a voltage adjustment method for performing voltage adjustment for correcting an unbalanced state of a three-phase voltage appearing between lines of a three-phase distribution line, and a voltage adjustment device used for implementing the voltage adjustment method. .
[0002]
[Prior art]
As a voltage adjusting device for adjusting the voltage of the distribution line, the one shown in FIG. 5 is used. In FIG. 5, T1 is a first autotransformer having a series winding Wa1 and a shunt winding Wb1 having taps 1 to 9, and T2 is a series winding Wa2 having a tap 1 to 9 and a shunt. A second autotransformer having a winding Wb2. These autotransformers are V-connected by connecting the ends of the shunt windings in common, and from the common connection point of the ends of the autotransformers T1 and T2 on the shunt winding side. The primary and secondary common terminals tv of the V phase are derived, and the primary terminals of the u phase and the w phase from the tap selectors TC1 and TC2 of the on-load tap changer for selecting the taps of the autotransformers T1 and T2, respectively. tu1 and tw1 are derived. Further, u-phase and w-phase secondary terminals tu2 and tw2 are derived from the respective through taps of the autotransformers T1 and T2. CT is a current transformer for detecting the u-phase and w-phase secondary currents, Wc1 and Wc2 are control windings provided in the autotransformers T1 and T2, respectively, and the control windings Wc1 and Wc2 are connected in series with each other. Then, the voltage detection winding for supplying a voltage detection signal to a control device (not shown) that controls the on-load tap changer and the power supply winding of the control device are used.
[0003]
The tap changer at load selects the taps of the same voltage of the two single-phase transformers T1 and T2 by simultaneously performing the switching operation of the tap selectors TC1 and TC2 according to the voltage of the distribution line on the load side. Thus, the voltage of the distribution line on the load side is adjusted.
[0004]
[Problems to be solved by the invention]
The three-phase voltage appearing between the lines of the three-phase distribution line is not always balanced, and if an unbalance occurs in the three-phase line current, it is inevitable that the line voltage also unbalances. If the unbalance of the three-phase voltages becomes severe, the voltage reaching the customer may be less than the specified value, which may adversely affect the customer's equipment. Therefore, it is desirable to adjust the magnitude and phase of the line voltage so that the three-phase voltage approaches the equilibrium state. However, in the conventional voltage regulator, the taps of the two transformers are always switched to the same voltage tap. Because the three-phase voltage is adjusted at the same time, if the three-phase voltage is unbalanced, the three-phase voltage output from the voltage regulator also becomes an unbalanced voltage that is unbalanced at the same rate. The function to correct the voltage to the equilibrium voltage could not be provided.
[0005]
An object of the present invention is to implement a voltage adjustment method for performing adjustment to correct the unbalanced voltage when the three-phase voltage appearing between the lines of the three-phase distribution line is unbalanced, and to implement the voltage adjustment method. It is in providing the voltage regulator used for.
[0006]
[Means for Solving the Problems]
In the voltage adjustment method of the present invention , two single-phase voltage regulators with two taps so that the magnitudes of the two-phase voltages of the three-phase voltages appearing between the lines of the three-phase distribution lines can be independently adjusted. Of the two single-phase voltage regulators, the remaining one-phase voltage of the three-phase voltages is used as a reference voltage, and the magnitude of one of the two-phase voltages is brought closer to the reference voltage. One of the process of switching one of the two taps and the process of switching the other tap of the two single-phase voltage regulators so that the magnitude of the other of the two-phase voltages approaches the reference voltage. Alternatively, the two-phase voltages are balanced until the magnitudes of both of the two-phase voltages are substantially equal to the magnitude of the reference voltage.
[0007]
As described above, the process of switching taps so that the magnitude of one of the two-phase voltages approaches the magnitude of the reference voltage using the one-phase voltage as a reference voltage, and the other of the two-phase voltages If one or both of the tap switching processes are performed so as to bring the magnitude of the reference voltage close to that of the reference voltage and the three-phase voltages are balanced, the tap positions necessary for balancing the three-phase voltages are obtained. For this reason, tap switching can be performed without performing complicated computations, and the configuration of the tap switching device can be simplified.
[0008]
In this specification, “to make both magnitudes of two-phase voltages substantially equal to the magnitude of the reference voltage” means that the difference between the magnitude of the voltage of each phase and the magnitude of the reference voltage is a predetermined tolerance. It means to be within the range (of course, including making the difference between the magnitude of the voltage of each phase and the magnitude of the reference voltage zero). That is, when adjusting the magnitude of each of the two-phase voltages to be approximately equal to the magnitude of the reference voltage, it is allowed to have some error.
[0009]
As described above, a voltage regulator is provided so that the magnitudes of the two-phase voltages out of the three-phase voltages can be independently adjusted, and the two-phase voltages can be adjusted using the one-phase voltage as a reference voltage. When voltage adjustment is performed so that the magnitude of both is substantially equal to the magnitude of the reference voltage, when the line voltage is an unbalanced three-phase voltage, the unbalance is corrected and the voltage regulation device is corrected. Since it can send out to the distribution line of a load side, the unbalanced state of the three-phase voltage of a distribution line can be improved. Moreover, if the unbalanced state of the distribution line voltage is improved, voltage adjustment (which can be performed using a conventional voltage regulator) for keeping the magnitude of the line voltage within the voltage management range can be easily performed. Therefore, high-quality power can be supplied to consumers.
[0010]
The voltage regulator for carrying out the method of the present invention independently adjusts the magnitudes of the two-phase voltages while keeping the magnitude of the one-phase voltage out of the line voltages of the three-phase distribution lines constant. The first and second tapped single-phase voltage regulators connected so as to be able to do so, and using the one-phase voltage as a reference voltage, the magnitude of both of the two-phase voltages is approximately equal to the magnitude of the reference voltage. A tap switching device that switches taps of the first voltage regulator and the second voltage regulator so as to be equal can be provided.
[0011]
The tap switching device performs a tap switching operation for switching the tap of the first voltage regulator so that one of the two-phase voltages approaches the reference voltage with the one-phase voltage as a reference voltage. And one or both of the tap switching operations for switching the taps of the second single-phase voltage regulator so that the other of the two-phase voltages approaches the reference voltage. It can be configured that the measurement is performed until the magnitudes of both are substantially equal to the magnitude of the reference voltage.
[0012]
In a preferred aspect of the present invention, a first auto-transformer provided with a tap in a series winding and a first tap selector that selects a tap of the first auto-transformer are provided. A second phase converter comprising: a single-phase voltage regulator; a second autotransformer having a tap provided in a series winding; and a second tap selector for selecting a tap of the second autotransformer. A single-phase voltage regulator and a tap switching device for individually switching the taps of the first and second single-phase voltage regulators are provided, and the pass-through tap of the first autotransformer is a second tap selector. And the primary and secondary terminals of one of the three phases are derived from the shunt winding side end of the first autotransformer. Also, the primary and secondary terminals of the other one phase are derived from the end of the second autotransformer on the shunt winding side, and the first tap selector and the through tap of the second autotransformer are used. Each of the remaining one-phase primary and secondary terminals is derived. In this case, the tap switching device uses the one-phase voltage appearing between the secondary terminals respectively derived from the shunt winding side ends of the first and second autotransformers as the reference voltage. As described above, the taps of the first single-phase voltage regulator and the second single-phase voltage regulator are switched so that the magnitudes of both of the other two-phase voltages are close to the magnitude of the reference voltage.
[0013]
Also in this case, the tap switching device uses, as a reference voltage, a one-phase voltage appearing between terminals respectively derived from the shunt winding side ends of the first and second autotransformers. Tap switching operation for switching the tap of the first single-phase voltage regulator so that the magnitude of one of the other two-phase voltages approaches the reference voltage, and the other of the other two-phase voltages One or both of the tap switching operations for switching the taps of the second single-phase voltage regulator so that the magnitude of the reference voltage is close to the magnitude of the reference voltage, and the magnitude of the other two-phase voltage is the magnitude of the reference voltage. It can be configured to perform until substantially equal to the above.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a connection diagram showing a configuration example of a voltage regulator used for carrying out the voltage regulation method according to the present invention, in which T1 is a series winding Wa1 having taps 1 to 7 and a shunt winding. A first autotransformer T2 having a line Wb1 and a second autotransformer T2 having a series winding Wa2 and a shunt winding Wb2 also having taps 1-7. TC1 and TC2 are first and second tap selectors for selecting taps of the first and second autotransformers T1 and T2, respectively. The first autotransformer T1 and the first tap selector. The first single-phase voltage regulator 11 is constituted by TC1, and the second single-phase voltage regulator 12 is constituted by the second autotransformer T2 and the second tap selector TC2. Although not shown, a tap switching device for individually switching the taps of the first and second single-phase voltage regulators 11 and 12 is provided.
[0015]
In the example of FIG. 1, each tap 4 of the first autotransformer T1 and the second autotransformer T2 is a through tap, and the through tap 4 of the first autotransformer T1 is the first tap. 2 is connected to the tap selector TC2. Then, a primary terminal tu1 and a secondary terminal tu2 of one of the three phases (U phase in the illustrated example) are derived from the end of the first autotransformer T1 on the side of the shunt winding Wa1, The primary terminal tw1 and the secondary terminal tw2 of the other one phase (W phase in the illustrated example) are derived from the end of the two-turn transformer T2 on the shunt winding Wb2 side. The remaining one-phase primary terminal tv1 and secondary terminal tv2 are derived from the through taps 4 of the first tap selector TC1 and the second autotransformer T2, respectively.
[0016]
When the two single-phase voltage regulators 11 and 12 are connected in this manner, they are derived from the ends of the first and second single-winding transformers T1 and T2 on the side of the shunt windings Wb1 and Wb2, respectively. The other two-phase voltages V1 and V2 appearing between the secondary terminals tu2 and tv2 and between the tv2 and tw2 are individually maintained with the one-phase voltage VB appearing between the secondary terminals tu2 and tw2 kept constant. Can be adjusted.
[0017]
The tap switching device (not shown) is provided between the secondary terminals tu2 and tw2 (u) respectively derived from the ends of the shunt windings Wb1 and Wb2 of the first autotransformer T1 and the second autotransformer T2. The first single-phase voltage regulator 11 is set so that the voltage of one phase appearing between the w-phases) is the reference voltage VB and one of the other two-phase voltages V1 and V2 is brought close to the reference voltage. A tap switching operation for switching the taps of the second single-phase voltage regulator 12 so as to bring the other of the other two-phase voltages close to the reference voltage VB. And performing one or both of these tap switching operations until both magnitudes of the other two-phase voltages are approximately equal to the magnitude of the reference voltage. The phase voltage is balanced.
[0018]
FIG. 2 is a vector diagram showing a tap switching operation when the imbalance of the three-phase voltage is corrected using the voltage regulator of FIG.
[0019]
First, the intersection of the vector of voltage V1 between the secondary terminals tu2 and tv2 (between u and v) and the vector of voltage V2 between tv2 and tw2 (between v and w) is at point a, and the three phases are unbalanced. Suppose you are in a bad state. At this time, first, the tap selected by the first tap selector TC1 is switched by one tap so that the magnitude of the voltage V1 between the u and v phases is changed closer to the magnitude of the reference voltage VB. As a result, the adjustment voltage ΔV11 is generated, and the intersection point of the vector of the voltage V1 between the u and v phases and the vector of the voltage V2 between the v and w phases is moved to the point b. Next, the adjustment voltage ΔV21 is generated by switching the tap selected by the second tap selector TC2 so that the magnitude of the voltage between the v and w phases approaches the magnitude of the reference voltage VB, and the voltage V1 and The intersection of the vectors of V2 is moved to point c. Next, by switching the tap selected by the first tap selector TC1 so that the magnitude of the voltage V1 between the u and v phases approaches the magnitude of the reference voltage VB, the adjustment voltage ΔV12 is generated to generate the voltage V1. And the intersection of the vectors of V2 is moved to point d. Thereafter, the same tap switching operation is repeated to sequentially generate the adjustment voltages ΔV22, ΔV13, and ΔV23, thereby moving the intersection of the vectors of the voltages V1 and V2 to the point e, the point f, and the point g. A balanced three-phase voltage is output from tv2 and tw2.
[0020]
FIG. 3 shows an unbalanced voltage range that can be adjusted to be balanced when the number of taps of each of the two autotransformers is 7, and the intersection of the vectors of the voltages V1 and V2 is shown in FIG. In this case, the unbalanced voltage can be converted to the balanced voltage by alternately switching the taps of the autotransformers T1 and T2 as described above. Note that the tap switching at the time of converting the unbalanced voltage to the balanced voltage does not necessarily require the tap switching of the two voltage regulators alternately. For example, the intersections of the vectors of the voltages V1 and V2 are P1 to P4 in FIG. In either case, it is possible to convert the unbalanced voltage into the balanced voltage only by switching the tap of either one of the voltage regulators 11 or 12.
[0021]
FIG. 4 shows an example of an algorithm of a program to be executed by the microcomputer when the tap switching device performs the above tap switching operation. When this algorithm is followed, first, in step 1, between u and v phases. When the voltage V1 is compared with the reference voltage VB between the u and w phases and V1> VB, the process proceeds to step 2 to switch the first tap selector TC1 to the 1-tap step-down side. If it is determined in step 1 that V1 <VB, the process proceeds to step 3 where the first tap selector TC1 is switched to the 1-tap boost side. When step 2 is completed, when step 3 is completed, and when it is determined in step 1 that V1 = VB (V1 and VB are substantially equal), then the process proceeds to step 4 between the v and w phases The voltage V2 is compared with the reference voltage VB between the u and w phases, and if V2> VB, the process proceeds to step 5 to switch the second tap selector TC2 to the 1-tap step-down side. If it is determined in step 4 that V2 <VB, the process proceeds to step 6 to switch the second tap selector TC2 to the 1-tap boost side. When step 5 is completed, when step 6 is completed, and when it is determined in step 4 that V21 = VB (V2 and VB are substantially equal), the process returns to step 1 and the above process is repeated.
[0022]
In the above example, the tap switching of the two voltage regulators is performed alternately so that the voltage finally becomes almost equal to the one-phase voltage using the two-phase voltage as the reference voltage. An example of this is shown. In the present invention, it is only necessary to convert the unbalanced voltage to the balanced voltage by adjusting the voltage of the other two phases using the voltage of one phase as a reference voltage, and switching the taps of the two voltage regulators. The method is not limited to the above example. For example, the remaining two-phase voltage adjustments necessary to output a three-phase balanced voltage based on the one-phase voltage that is not affected by the tap switching of two voltage regulators that adjust the two-phase voltage The tap position of the voltage regulator may be obtained by calculation, and the taps of the two voltage regulators may be switched to the obtained taps.
[0023]
In the above example, two voltage regulators are used that use a single-winding transformer as a voltage-regulating transformer, but the voltage-regulating transformer that can be used in the present invention is limited to the single-winding transformer. It is not done.
[0024]
【The invention's effect】
As described above, according to the present invention, the voltage regulator is provided so that the magnitudes of the two-phase voltages among the three-phase voltages appearing between the lines of the three-phase distribution lines can be independently adjusted, and 3 Since the remaining one phase voltage of the phase voltages is used as a reference voltage, the voltage adjustment is performed so that the magnitude of the voltage of the two phases is substantially equal to the magnitude of the reference voltage. Is an unbalanced three-phase voltage, there is an advantage that the unbalance can be corrected by a distribution line on the load side of the voltage regulator.
[Brief description of the drawings]
FIG. 1 is a connection diagram illustrating a configuration example of a main part of a voltage regulator according to the present invention.
FIG. 2 is a vector diagram showing an example of the adjustment operation of the voltage regulator of FIG.
3 is a vector diagram showing an adjustable range when a three-phase unbalanced voltage is adjusted to a balanced voltage by the voltage regulator of FIG. 1. FIG.
4 is a flowchart showing an example of a control algorithm of the tap switching device of the voltage regulator of FIG. 1;
FIG. 5 is a connection diagram illustrating a configuration example of a conventional voltage regulator.
[Explanation of symbols]
11 1st single phase voltage regulator 12 2nd single phase voltage regulator T1 1st single turn transformer TC1 1st tap selector T2 2nd single turn transformer TC2 2nd tap selector tu1, tv1, tw1 primary terminals tu2, tv2, tw2 secondary terminals

Claims

Two single-phase voltage regulators with taps are provided so that the magnitude of the two-phase voltage among the three-phase voltages appearing between the three-phase distribution lines can be adjusted independently,
One of the two single-phase voltage regulators such that the remaining one-phase voltage of the three-phase voltages is a reference voltage, and the magnitude of one of the two-phase voltages is brought close to the reference voltage. One of a process of switching the taps and a process of switching the other taps of the two single-phase voltage regulators so that the magnitude of the other of the two-phase voltages approaches the magnitude of the reference voltage. Alternatively, the voltage distribution method of the distribution line is characterized by balancing the three-phase voltages by performing both of them until the magnitudes of both of the two-phase voltages are substantially equal to the magnitude of the reference voltage.

A single-phase voltage regulator with first and second taps connected so as to be able to independently adjust the magnitude of the two-phase voltage among the three-phase voltages appearing between the lines of the three-phase distribution line; The first voltage regulator and the second voltage regulator are configured so that the magnitude of both of the two-phase voltages is approximately equal to the magnitude of the reference voltage, using the remaining one-phase voltage of the three-phase voltages as a reference voltage. And a tap switching device for switching taps of the voltage regulator.

A single-phase voltage regulator with first and second taps connected so as to be able to independently adjust the magnitude of the two-phase voltage among the three-phase voltages appearing between the lines of the three-phase distribution line; Using the remaining one-phase voltage of the three-phase voltages as a reference voltage, the tap of the first voltage regulator is set so that one of the two-phase voltages approaches the reference voltage. One or both of a tap switching operation for switching and a tap switching operation for switching the tap of the second single-phase voltage regulator so that the other of the two-phase voltages approaches the reference voltage. And a tap switching device for performing until the magnitudes of both of the two-phase voltages are substantially equal to the magnitude of the reference voltage.

A first single-phase voltage regulator comprising: a first autotransformer provided with a tap in a series winding; and a first tap selector that selects a tap of the first autotransformer;
A second single-phase voltage regulator comprising: a second autotransformer provided with a tap in the series winding; and a second tap selector for selecting a tap of the second autotransformer;
A tap switching device for individually switching the taps of the first and second single-phase voltage regulators;
The through tap of the first autotransformer is connected to the second tap selector, and the primary phase of one of the three phases from the end of the shunt winding side of the first autotransformer And the secondary terminal is derived, and the primary and secondary terminals of the other one phase are derived from the shunt winding side end of the second autotransformer, and the first tap selector and the second The primary and secondary terminals of the remaining one phase are derived from the through taps of the two-turn transformer,
The tap switching device uses a one-phase voltage appearing between the secondary terminals respectively derived from the shunt winding side ends of the first auto-transformer and the second auto-transformer as a reference voltage. As described above, the taps of the first single-phase voltage regulator and the second single-phase voltage regulator are switched so that the magnitudes of both of the other two-phase voltages are substantially equal to the magnitude of the reference voltage. A voltage adjusting device for a distribution line, characterized in that

A first single-phase voltage regulator comprising: a first autotransformer provided with a tap in a series winding; and a first tap selector that selects a tap of the first autotransformer;
A second single-phase voltage regulator comprising: a second autotransformer provided with a tap in the series winding; and a second tap selector for selecting a tap of the second autotransformer;
A tap switching device for individually switching the taps of the first and second single-phase voltage regulators;
The through tap of the first autotransformer is connected to the second tap selector, and the primary phase of one of the three phases from the end of the shunt winding side of the first autotransformer And secondary terminals are derived , The primary and secondary terminals of the other one-phase are derived from the shunt winding side end of the second autotransformer, and the first tap selector and the second autotransformer The remaining one-phase primary and secondary terminals are derived from the through taps,
The tap switching device uses a one-phase voltage appearing between the secondary terminals respectively derived from the shunt winding side ends of the first auto-transformer and the second auto-transformer as a reference voltage. A tap switching operation for switching the tap of the first single-phase voltage regulator so that the magnitude of one of the other two-phase voltages approaches the magnitude of the reference voltage, and the other two-phase voltages One or both of the tap switching operations for switching the taps of the second single-phase voltage regulator so that the other of the two approaches the reference voltage. A voltage adjusting device for a distribution line, wherein the voltage adjusting device is configured to perform until the magnitude is substantially equal to the magnitude of the reference voltage.