JP3591247B2 - Loosely coupled power system controller - Google Patents

Description

【００１７】
で表すものとし、また、制御対象とする設備は開閉器の入り切り状態とする。もちろん地域系統内の変電所タップ比，調相設備の投入，発電機ＡＶＲ端子電圧の変更，発電機有効電力，無効電力出力変更も考えることが可能である。また、制約条件は各発電機の有効電力，無効電力の出力上下限値，変圧器タップの設備上下限送電線，変圧器の潮流値の上下限，調相設備の機器数あるいは容量の上下限，発電機ＡＶＲ端子電圧上下限値とする。
【００１８】
このような仮定のもとで、まずラグランジェ関数を以下のように作成する。
【００１９】
【数２】

【００２０】
この式を各変数で微分を行い、式３の行列、あるいは右辺のベクトルに対応する数値を計算する（手順３０３，手順３０４）。
【００２１】
【数３】

【００２２】
ここで右辺のベクトルは対象とする地域系統内の観測値である。次に全体の計算の実行の流れについて説明する。まず手順３０１にて計算に必要な情報、たとえば本実施例の場合、現状の対象系統内の物理量，電力方程式に関する情報を収集する。また、この手順では変数の初期化も同時に行う。次に手順３０２にて前記した制約条件とその値を設定する。次に手順３０３にて（式３）の係数行列を作成する。これは（式３）より各変数に関する一次微分，二次微分を予め求めておき、前記した変数の値を代入することにより係数行列の要素を計算する。次に手順３０４にて（式３）の右辺の値を変数ｘを電力方程式に代入することにより求める。以上の計算が終了したら手順３０５にて分解計算を行い解Δｘを求める。この値が手順３０６にて繰り返し計算一回前の値と比較して予め設定した閾値よりも小さい場合は収束と見なして手順３０７に進む。そうでない場合は手順３０３に戻り繰り返し計算を引き続き行う。手順３０６にて収束と判定された後に手順３０７にて求めた解が制約条件を違反していないかを判定する。違反がなかった場合は終了し、違反があった場合は違反した変数に０．０以外のペナルティ係数αを掛けて手順３０３に戻り計算を継続する。
【００２３】
以上に示した具体的設備の決定方法の実施例の具体例を以下図４を用いて説明する。ここでは任意の地域に存在する疎結合電力系統制御装置が他の地域の系統状態と設備運転状態を必要とし、かつ他の地域系統との系統切替えなどの操作を必要とする場合である。この場合は図４の手順４０１にて、制御を行おうとする地域（以下自地域）に接続、あるいは自地域の設備が他地域へ分離可能であるかをデータ収集１装置１０２の情報をもとに探索する。次に手順４０２にて他地域との制御設備が存在するか否かの判定を行う。ここで他地域との協調がとれない場合は手順４０３にて自地域の制御設備を用いて制御が可能であるかどうかを判定する。制御可能である場合は該当する設備を第一の実施例と同様に求める。該当する設備がない場合は状態評価指標を悪化させている自系統内の設備を検出し、該当する設備を地域系統から切り離す。手順４０２にて他地域との協調をとることが可能である場合は手順４０６にて協調可能な設備を手順４０７以下で使用する定式化に利用できるように設定する。その後に手順４０７，４０８，４０９にて図３に示した最適化方法を用いて解を求め、設備操作に対する解が求まった場合は手順４１０にて該当する設備の操作を制御指令装置１０６に発行する。そうでない場合は手順４０３に戻り前記した処理を実行する。
【００２４】
次に本実施例で具体的な状態評価指標を用いた例について説明する。評価指標として電圧の不平衡度を平衡電圧が印加された場合に生じる不平衡電圧比と定義した場合、目的関数は地域系統内の各母線における電圧不平衡度の二乗和とし、制御変数、すなわち式３の左辺のΔｘは各ノードの各相における有効・無効電力注入量，制約条件は不平衡を解消するための設備の上下限、たとえば調相設備の上下限、あるいは送電線の潮流上下限値，各母線の電圧上下限値などである。式３の右辺に相当する数値は各ノードの各相の電圧を用いる。係数行列は電力方程式をもとに作成する。また、評価指標として周波数変動を用いる際には、目的関数を地域系統内の周波数の変化量の二乗と、基準周波数からの差の二乗を最小とし、式３の左辺のΔｘは発電機の有効電力出力調整値，発電機の並解列を表す情報，他地域への送電情報等を用い、制約条件として各発電機の設備上下限，出力変化率，系統中の送電線の潮流上下限値などを用いる。また、評価指標として短絡電流を設定した場合は、目的関数を他地域との連系点にある変圧器の定格短絡容量と計算による短絡容量との差の二乗を最小化するものとする。式３の左辺のｘに相当するのは変圧器の使用・停止・切替え，送電線の使用・停止・切替え，系統分割また、評価指標を、母線分割情報などとする。次に制約条件は設備上下限，安定度指標とする。また評価指標として電圧安定度を設定した場合は、目的関数をＰＶカーブを作成した際に求められる有効電力増加余裕量と現在有効電力負荷の総和の差の二乗を最大化するものとする。式３の左辺のｘに相当するのは電圧の大きさの変化分，位相角の変化分，変圧器のタップ比の変化分，ＡＶＲ発電機端子電圧値の変化分，調相設備の投入量の変化分などとする。また、制約条件は設備上下限，母線電圧の上下限とする。次に評価指標として定態安定度を設定した場合は、目的関数を相差角の和を最小化するものとする。式３の左辺のｘに相当するのは発電機有効電力出力の変化分，発電機の並解列情報，電源制限情報などとする。また、制約条件は設備上下限，母線電圧の上下限とする。
【００２５】
以上の疎結合電力系統制御装置の模式図を用いた例を以下図５，図６，図７，図８示すモデル系統を用いて説明する。図５は疎結合電力系統のモデルを示している。５０１，５０２，５０３はこれまで地域と呼んでいた部分系統に相当する。また、４１１，４１２，４１３，４１４，４１５，４１６，４１７，４１８は送電線を示し、太線が使用中の送電線，細線が使用を停止している送電線を示す。また、○印は変電所を示し、この変電所には複数の発電装置と負荷装置が存在しているものとする。また、各変電所は変圧器によって接続されているものと仮定する。図５の実施例では説明の便宜を図るために目的関数を一つに限った場合を考え、ここでは高調波を状態評価指標とする。図中、●印で表した４２１， ４２２，４２３の変電所にて高調波電圧ひずみが大きく発生しているものとする。また、地域４０２ではそれ以外の変電所では高調波は発生していないものとする。ここでは高調波の発生要因である地域間内のコンデンサの授受を行うことにより超過地域の高調波低減を図ることを目的とする。図４中、４２１で高調波ひずみ量が許容規定値５％よりも１％超過，４２２で許容規定値よりも１％超過，４２３で許容規定値よりも３％超過している状態であるとする。また、地域４０１では高調波ひずみは規定値よりも許容規定値よりも３．５％ 小さく地域４０３では許容規定値よりも４．５％ 小さいものと仮定する。また基準値を０％と設定する。この場合の目的関数を基準値からの偏差の二乗和とすると目的関数は図５の状態で１．５＊１．５＋９．０＊９．０＋０．５＊０．５＝８３．５となる。この状態では地域５０２での高調波歪みが９％であるので、この違反を解消しつつ、かつ隣接している地域系統で目的関数が最小となる開閉器の操作を求めることになる。操作方法の候補として４２３を地域４０１へ切替え、４２１，４２２を地域４０３に切替える候補と、４２３を地域４０３へ切替え、４２１，４２２を地域４０１に切替える候補が最適化問題を解く際に求められたとする。この２候補のうちの目的関数を小さくするほうを選ぶことになるので、目的関数を計算すると、最初の候補の場合は３．５＊３．５＋４．０＊４．０＋３．５＊３．５＝４０．５，二番目の候補の場合は４．５＊４．５＋４．０＊４．０＋２．５＊２．５＝４２．５となり、最初の候補を操作として選択することになる。図３に示した最適化の過程は簡単に示すと以上のようになる。この結果にしたがって制御操作を行った結果例が図６となる。これまで停止していた送電線４１２，４１５，４１６を接続し、送電線４１８，４１４，４１７を停止することにより系統構成の切替えを行う。各地域は図６に示すように変更される。このように他地域との系統切替えを協調して行う場合は、データ収集装置１０２を通じて制御情報を他地域に伝達、あるいは他地域より制御情報を受け取る。
【００２６】
次に状態評価指標を電圧安定度とした場合の実施例について図７，図８を用いて説明する。図７の太線，細線，白丸の意味は図５と同様である。また、６３１，６３４，６３５は電圧調整機器である調相設備、６３２，６３３はＡＶＲ端子電圧を制御する発電機である。電圧安定度の目的関数を現時点での負荷１００％とＰＶカーブにて求めることが可能である限界負荷との差の二乗和とする。また電圧安定度の最低必要値を現時点での需要量から＋６％と仮定し、地域７０１では＋７％、地域７０２では＋３％、地域７０３では＋１０％であるとする。すなわち、地域７０２では電圧安定度を高める必要がある。このときの各地域系統中の電圧制御設備の利用状況を地域７０２ではＡＶＲ発電機端子電圧が１％上昇の余裕、変圧器タップは上昇余裕なし、調相設備も上昇余裕がないと仮定する。また、地域７０１では他地域に接続が可能なＡＶＲ発電機端子電圧上げ余裕（機器７３２）が０．５％、変圧器タップの上昇余裕が０％、調相設備上昇余裕が１（機器７３１）％の機器があるとし、地域７０３では他地域に接続可能なＡＶＲ発電機端子電圧上げ余裕が１（機器７３３）％、変圧器タップの上昇余裕が０％、調相設備上昇余裕が１％（機器７３５）と４％（機器７３４）の機器があるとする。目的関数は６％の余裕を保てる場合の限界負荷と現在負荷の差の二乗和とすると、図３に代表される最適化手法で地域７０２に６３１，６３２，６３４，６３５を用いれば電圧安定度不足が解消されるとの結果を得たとする。この場合は地域７０２は地域７０１，７０３と協調をとり７１２，７１３，７１５，７１６の送電線を運転し、送電線７１７，７１８を停止する。制御後の結果を図８に示す。なお、ここまでの実施例では説明の便宜上、目的関数を一種類の状態評価指標を用いて行ってきたが、任意の種類の状態評価指標を組みあわせて最適化計算を行うことも可能である。また、一種類の状態評価指標を用いて最適化計算を行い、この計算を結果を受けて状態評価指標を替えた後にさらに何度も行うことも可能である。
【００２７】
ここまでの制御操作はＮｅｗｔｏｎ法を用いた最適化手法を用いたが、線形計画法をはじめとする数理計画法を用いた最適化手法を用いても実現が可能である。
【００２８】
以上のように本発明の疎結合電力系統制御装置の第一の実施例を用いて、制御範囲を系統状況を見ながら柔軟に変更することにより、これまで同時に考慮されていなかった電圧安定度，高調波対策等の複数指標のトレードオフを満足する電力系統の制御、すなわち安定した電力供給が可能となる。このことは副次的に電力系統中の電気の流れを一定方向に保つことが可能となるので、分散型電源導入による様々な問題点、特に逆潮流問題に代表される問題解決のために膨大に必要となる投資を軽減することが可能となる。またこの装置を導入する効果として、各地域で発生したエネルギー需給のアンバランスをすべて上位系の設備を用いて制御する従来方法と比較して、各地域系統で自律的に状態評価指標をもとに制御を行うために、上位系での一括制御負担に対する負荷が軽減する効果が期待できる。
【００２９】
本発明の疎結合電力系統制御装置の第二の実施例は第一の実施例が指標をもとに行う制御の決定を最適化問題ととらえて解いていたのに対し、予め決められたフローチャートに基づいて他地域との協調をとりながら制御を実行する方法である。この第二の実施例について図９，図１０を用いて説明する。なお、本実施例では物理量の監視点を設け、その監視点を各地域間を接続する送電線の電力潮流値であることを仮定する。また、電力供給コストを仮定し、それは予め順番を決めておく。まず（１）地域内の分散型電源の発電量が地域内の負荷量より少ない、（２）地域内の分散型電源の発電量が地域内の負荷量より多い、の２通りのケースについて述べる。１）のケースの場合を図９を用いて説明する。自地域内の発電量と負荷量を手順９０１にて比較した結果発電量が不足している場合、これは隣接している他地域から自地域内に電力を調達しなければならない場合である。その場合、まず自地域内のＩＰＰの調整が可能かどうかを手順９０２で判定する。これが可能である場合は手順９０３にて自系統内のＩＰＰ発電機に出力変動要請を行い自系統内の需給バランスを確保する。ＩＰＰの調整が不可能である場合は自地域内に接続している他地域があるかを手順９０４にて検出する。さらに手順９０５にて隣接している他地域に電力融通が可能であるかを他地域の情報を取得してその可否を決定する。隣接する他地域からの電力供給が不可能である場合は手順９０７に進む。隣接する他地域からの電力供給が可能である場合は手順９０６にて発電量を調達する。その一方でもし手順９０５にて条件を満たす他地域が見つけられなかった場合は、引き続き他地域との協調により監視点潮流量を一定に保つため手順９０７にて自地域内の負荷の一部あるいはすべてを受け入れることが可能な他地域を探索する。このことが可能である場合には手順９０８にて自地域内の開閉器を操作して負荷を切り離し他地域に接続する。このことが不可能である場合は、自地域に存在する負荷にデータベース１０３にて設定されている優先順位の高い順から監視点の値が設定値になるように負荷遮断を手順９０９にて行う。
【００３０】
次に（２）のケースの場合を図１０を用いて説明する。自地域内の発電量と負荷量を手順１００１にて比較した結果負荷量が不足している場合、これは隣接している他地域に自地域内より電力を調達しなければならない場合である。その場合、まず自地域内のＩＰＰの調整が可能かどうかを手順１００２で判定する。これが可能である場合は手順１００３にて自系統内のＩＰＰ発電機に出力変動要請を行い自系統内の需給バランスを確保する。ＩＰＰの調整が不可能である場合は自地域内に接続している他地域があるかを手順１００４にて検出する。さらに手順１００５にて隣接している他地域へ電力融通が可能であるかを他地域の情報を取得してその可否を決定する。隣接する他地域への電力供給が不可能である場合は手順１００７に進む。隣接する他地域への電力供給が可能である場合は手順 １００６にて隣接地域に発電量を送る。その一方でもし手順１００５にて条件を満たす他地域が見つけられなかった場合は、引き続き他地域との協調により監視点潮流量を一定に保つため手順１００７にて自地域内の発電設備の一部あるいはすべてを受け入れることが可能な他地域を探索する。このことが可能である場合には手順１００８にて自地域内の開閉器を操作して発電設備を切り離し他地域に接続する。このことが不可能である場合は、自地域に存在する負荷にデータベース１０３にて設定されている優先順位の高い順から監視点の値が設定値になるように電源制限を手順１００９にて行う。
【００３１】
以上述べた実施例では制御の順番が予めＩＰＰ，地域間電力融通，負荷切替え，電制，負荷制の順番であったが、この順番が制御実行時の状況を考慮してこれ以外の任意の組みあわせであっても構わない。
【００３２】
以上の本発明の疎結合電力系統制御装置の第二の実施例を用いて、制御範囲を系統状況を見ながら柔軟に変更することにより、これまで同時に考慮されていなかった電圧安定度，高調波対策等の複数指標のトレードオフを満足する電力系統の制御、すなわち安定した電力供給が可能となる。この実施例は第一の実施例と異なり最適化計算を行わないため制御解が確実に求められることになり、制御の信頼性が増すこととなる。特に第二の実施例は第一の実施例での同等の効果をリアルタイム制御にて行う際に有効である。
【００３３】
第三の実施例は第一の実施例での状態評価装置での状態評価を将来時間断面にわたって行う例である。将来時間断面にわたって行う場合には将来系統予測が必要となる。この方法はデータベース１０３中に格納されている過去の履歴データと、第一の実施例で推定した現在の系統状態をもとに将来時点の系統状態を予測して将来時点での地域系統の各種物理量と前記状態監視指標を算出する方法が適している。本方法については以下の公知例に詳細が述べられている。
【００３４】
中島，大久保，松本，石田，田村，次期中央給電指令所向け数時間先潮流状態予測（ＤＰＦ）システムの開発．電気学会全国大会，１９９５，１２９１。
【００３５】
以上の本発明の疎結合電力系統制御装置の第三の実施例を用いて、将来予測を用いた系統制御を行うことにより、系統状態の急変時にも安定した電力供給が可能となる。また、第三の実施例を系統運用計画立案にも用いることが可能であるため、将来の分散型電源の導入計画を見ながら、分散型電源導入による問題点を予め解決するための補償設備の導入計画立案に用いることが可能となるため、将来時点での効率的な設備投資が可能となる。
【００３６】
【発明の効果】
以上のように本発明の疎結合電力系統制御装置では、地域系統内における電力系統の特徴を表す物理量を該地域系統より収集するデータ収集装置，前記データ収集装置で収集した情報を格納するデータベース，前記データ収集装置とデータベースの情報をもとに該地域系統の状態を評価する状態評価装置，各地域毎の状態評価結果と前記物理量をもとに作成する電力系統の目的関数を他地域系統と協調して最適化する開閉器操作指令信号を発生する制御計算装置，前記制御計算装置での計算結果を該地域系統中の制御設備と他地域系統の制御設備に指令を行う制御指令装置を有するので、複数の目的関数のトレードオフを考慮しながら、常に安定した電力供給を全体系統にて実現することが可能となる。
【図面の簡単な説明】
【図１】本発明の代表的実施例を表す図面。
【図２】データベースのデータ格納の一例。
【図３】最適化手法を用いて解く場合のフローチャート。
【図４】他地域と協調をとりながら制御を実行する場合のフローチャート。
【図５】モデル例を表す図である。
【図６】モデル例を表す図である。
【図７】モデル例を表す図である。
【図８】モデル例を表す図である。
【図９】制御計算装置のロジックを用いる実施例で発電量が過剰である場合を表す図面。
【図１０】制御計算装置のロジックを用いる実施例で負荷量が過剰である場合を表す図面。
【符号の説明】
１０１…制御対象となる電力系統、１０２…データ収集装置、１０３…データベース、１０４…状態評価装置、１０５…制御変数決定装置、１０６…制御計算装置、１０７…制御指令装置、１１１，１１２，１１３…地域系統、１５１〜 １６０…開閉器、２０１…設備データベース格納の一例、２０２…系統中の物理量に関するデータベース格納の一例、２０３…制御可能設備に関するデータベースの一例、２０４…監視点に関するデータベースの一例、２０５…電制負荷制実行優先順位に関するデータベースの一例、３０１…必要データ読み込み手順、 ３０２…制約条件設定手順、３０３…係数行列作成手順、３０４…右辺作成手順、３０５…分解代入計算手順、３０６…収束判定手順、３０７…制約違反判定手順、３０８…ペナルティ設定手順、４０１…他地域設備探索手順、４０２…設備存在手順、４０３…設備制御可能判定手順、４０４…設備遮断手順、４０５… 設備制御手順、４０６…設備格納手順、４０７…ｎｅｗｔｏｎ法の定式化手順、４０８…解を求める手順、４０９…計算解存在判定手順、４１０…系統操作指令手順、５０１，５０２，５０３，５０４，５０５，７０１，７０２，７０３…地域、 ５１１，５１２，５１３，５１４，５１５，５１６，５１７，７１１，７１２，７１３，７１４，７１５，７１６…送電設備、５２１，５２２，５２３，７２１，７２２，７２３…変電所、７３１，７３２，７３３，７３４，７３５…電圧無効電力調整設備、９０１，１００１…地域系統内需給バランス判定手順、９０２，１００２…ＩＰＰ出力変化可能判定手順、９０３，１００３…ＩＰＰ出力調整手順、９０４，１００４…隣接地域検出手順、９０５，１００５…電力供給判定手順、９０６，１００６…発電量融通手順、９０７，１００７…負荷切り離し可能判定手順、９０８，１００８…負荷切替手順、９０９…負荷遮断手順、１００９…電制実行手順。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a method and an apparatus for controlling a power system in which a large number of distributed power sources exist.
[0002]
[Prior art]
In the future, due to deregulation of the Electricity Business Law, large-scale consumers or ordinary households will be connected to batteries of the voltage class (hereinafter referred to as "regional system" in this specification) by batteries, wind power, There is a tendency for a large amount of distributed power sources represented by solar power generation to be introduced. Apart from this, the large customers tend to install generators that are out of the control of the electric power company as a business, and carry out a power generation business under the name of so-called IPP (Independent Power Producers). In addition, in order to reduce electricity costs, the use of distribution facilities is reduced by generating, transmitting, and transforming power in municipal or smaller units rather than large-capacity transmission by constructing long-distance transmission lines. And there is a tendency to supply cheap electricity to consumers.
[0003]
The current control system monitors the output of the power plant whose command center is in the command range, or the voltage of the entire system, and sets the most desirable power system operation target value based on a single objective function. In general, the actual operation is performed by transmitting the set value to a control station close to the customer. Generally, overload of active power flow or voltage stability is individually used as an objective function according to a system condition.
[0004]
However, when the above-mentioned distributed power supply equipment is introduced in a large amount in a power system, each of the distributed power supply equipments has a large degree of freedom of operation, so that it is conceivable that the voltage quality is greatly reduced even in a steady state. . That is, in addition to the objective functions individually considered according to the system status, control is performed by considering a plurality of objective functions, such as harmonics and steady state stability, which need not be considered in the steady state. There is a need. Since these objective functions have a correlation with each other, they need to be considered at the same time as a multi-objective function. As a method for solving such a problem, there has been conventionally known a method of optimizing an output amount of equipment existing in a system under a certain constraint using a multi-objective function.
[0005]
[Problems to be solved by the invention]
However, in the conventional power system operation problem using the multi-objective optimization method, the range of the system to be optimized and the equipment to be operated are determined in advance, and the optimization problem is solved within that range. In this method, there is a problem that the system range itself to be a system target is a large constraint, and the degree of freedom of control is small. This means that the distribution of distributed power sources will not be distributed evenly in each region as in the equipment planning that electric power companies have done to date, but will be greatly unevenly distributed in each region. In the operation of the power system using the multi-objective optimization method that only adjusts the output amount of the power supply, it is obvious that the choice of the control policy is limited, and a failure occurs in the stable power supply.
[0006]
It is an object of the present invention to solve the above-mentioned problems using the conventional multi-objective optimization problem in the operation of a power system, and to provide an apparatus that always realizes stable power supply in the whole area.
[0007]
[Means for Solving the Problems]
In the present invention, in order to solve the above-mentioned problems, instead of simply using multi-objective optimization to determine the output amount of equipment in the system to be optimized, control execution of a regional system to be controlled is performed. A stable power system control is performed by freely changing the target system range by using a switching operation of a switch connecting the respective regional systems according to the system status at the time. The on / off operation of the switch is calculated as an optimization problem using a multi-objective function. According to the present invention, for example, the control target value is maintained for each regional system in a balance between the energy generation amount and the energy consumption amount between the neighboring regional systems, and the frequency fluctuation and the voltage generated secondary to maintain the balance are maintained. It is characterized by minimizing undesirable physical phenomena occurring in the power system such as reduction and generation of harmonics, and minimizing the cost spent on equipment control necessary for maintaining the balance. Here, various physical quantities (evaluation values) at the time when the data were acquired for each regional system are evaluated based on the collected data (system state evaluation). If the evaluation is not desirable, the evaluation value is set to a desirable evaluation value. Then, a part of the other regional system is merged with the partial system by switching operation of the switch to determine a control method in the regional system. This decision is an optimization problem in which the above-mentioned evaluation value is minimized or maximized within a range that satisfies the constraints of various facilities in the regional system or within a range that satisfies the constraints of various facilities in other regions. Do. Alternatively, since a solution obtained as an optimization problem does not greatly differ from an actual control policy, a control method for maintaining a predetermined physical quantity in the power system in a certain range is derived.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows an example of a loosely coupled power system control method and apparatus for implementing the method of the present invention.
[0009]
As shown in the figure, this apparatus is provided with loosely coupled power system control devices 101-a, 101-b, 101-b, respectively for power systems divided into small-scale systems 111, 112, 113 (hereinafter, referred to as "regions"). 101-c (hereinafter abbreviated as 101). The power system control device 101 in each regional system has a data collection device as each of the loosely coupled power system control devices 102-a, 102-b, 102-c, a database 103, a state evaluation device 104, and a control calculation device. 105 and the control command device 106 are connected. Data collection devices in any region are connected between each device to obtain information from other regional systems.
[0010]
In each area 111, 112, and 113, there are a plurality of power generation facilities, energy generation and consumption facilities represented by large-scale customers and general consumers. In addition, those facilities are connected by power transmission facilities through switches 151 to 160. In the example of FIG. 1, it is assumed that the switches 153 to 156 are in an open state, and the areas 111, 112, and 113 are connected only by the transmission lines 161 and 162, respectively. Each power generation facility includes a battery, a wind power generator, a solar power generator, a generator, and the like, which are installed by a customer. In addition, sensors for measuring various physical quantities such as power generation and load are attached to distribution facilities such as power generation facilities and load facilities in each region. Data is collected by the device 102 from these sensors. The data acquired by the device 102 is sent to and stored in the database 103. At the same time, the data acquired by the device 102 is sent to the state evaluation device 104. Further, the control computer 105 calculates a control operation based on the data acquired by the device 102 and the information in the database 103. The result calculated here is sent to the control command device 106 and issues a control command to the equipment in the power system.
[0011]
Next, the specific operation of each device in FIG. 1 will be described below. The data collection device 102 collects physical quantities representing characteristics of each facility, for example, current, voltage, etc., measured based on measuring instruments installed in each facility in the power system via a communication line or using wireless communication. I do. The database 103 stores data collected by the data collection device in a format indicated by 201, 202, 203, and 204 in FIG. Reference numeral 201 denotes data relating to facilities in the system, 202 denotes data of observed physical quantities in the system, 203 denotes data of controllable facilities, and 205 denotes a priority table which is referred to when executing load shedding and power shutoff. Reference numeral 204 stores a connection point between regions and a reference value of a physical quantity related to the connection point or a range value thereof.
[0012]
The state evaluation device 104 evaluates the state of each regional system at the present time based on the information in the device 102 and the database 103. In order to evaluate the current state, various physical quantities are calculated based on data collected by the data collection device 102, and a state monitoring index represented by stability is calculated. Alternatively, it is also possible to measure the waveform from a sensor directly connected to the bus, such as a voltage, to calculate the influence of harmonics. In addition, if the amount of information is insufficient with only the physical quantities that observe these status monitoring indices,
F. F. Wu, Power System State Estimation: a survey. Electrical Power & Energy Systems, 12 (1990), 80-87.
Is performed to obtain plausible values of various physical quantities represented by, for example, the magnitude of the bus voltage and the phase angle in the target partial area, and thereafter, state monitoring indices such as transmission loss and short-circuit current Values, voltage stability, transient stability, frequency fluctuation rate, and the like can be obtained.
[0013]
Examples of the state evaluation index include the ratio of the magnitude of the zero-sequence voltage and the magnitude of the positive-sequence voltage indicating the degree of voltage imbalance, or the magnitude of the voltage imbalance represented by the ratio of the magnitude of the negative-sequence voltage and the magnitude of the positive-sequence voltage. The degree of harmonic generation expressed by the magnitude of the nth harmonic generated in the system, the frequency fluctuation expressed by the frequency of the local system and its fluctuation amount, the load characteristics within each local system, transmission loss, short-circuit current, voltage stability , Transient stability, power generation cost, facility operation cost, etc.
[0014]
The control calculation device 105 determines the upper and lower limit values of various indices set in advance based on the various status evaluation indices calculated by the status evaluation device, or the upper and lower limit values of various indices dynamically determined for each control time for each region. Compared with the lower limit, if the control is performed based on the evaluation at the current time as described above, an index having a violation at the current time, or if control is performed based on the evaluation index at a future time, the current time is used. Detect indicators that a violation is likely to occur in the future even if no violation has occurred. Based on the result, an appropriate operation of the equipment in the local system is determined so as to eliminate the violation occurrence index. The operation of the equipment here will be considered mainly on the switching of a switch for changing the system connection between an arbitrary regional system and another regional system. Of course, the adjustment of the active power output of the generator in any regional system, the adjustment of the reactive power output of the generator, the parallel arrangement of the generator, the switching of the generator system between any regional systems, and the transformation in any region Adjustment of taps, adjustment of reactive power output of synchronous phase shifter in any area, use, stop, changeover of power transmission equipment that exists in any system or connect to any system, in any regional system Use, stop, switchover of transformers, load receiving, switching, stop of load in any regional system or between regional systems, or use, stop, or use of phase adjusting equipment in any regional system It is also possible to take into account the change in the generator terminal voltage value inside.
[0015]
Next, a method for determining the above-described equipment operation will be described. In this embodiment, an example in which the state evaluation index minimizes the transmission line active power loss will be described. Although there are various known methods for minimizing, an embodiment using an optimization method using Newton's method as the optimization method will be described below with reference to FIG. Note that the objective function for using the optimization method is
[0016]
(Equation 1)

[0017]
And the equipment to be controlled is in the on / off state of the switch. Of course, it is also possible to consider changing the tap ratio of the substation in the local system, turning on the phase adjustment equipment, changing the generator AVR terminal voltage, and changing the generator active power and reactive power output. The constraints are the upper and lower limits of the output of the active power and the reactive power of each generator, the upper and lower limits of the transformer tap equipment, the upper and lower limits of the power flow of the transformer, and the upper and lower limits of the number or capacity of the phase adjustment equipment. , Generator AVR terminal voltage upper and lower limits.
[0018]
Under such an assumption, first, a Lagrange function is created as follows.
[0019]
(Equation 2)

[0020]
The equation is differentiated by each variable, and a numerical value corresponding to the matrix of the equation 3 or the vector on the right side is calculated (steps 303 and 304).
[0021]
(Equation 3)

[0022]
Here, the vector on the right side is an observed value in the target regional system. Next, the flow of execution of the entire calculation will be described. First, in step 301, information necessary for calculation, for example, in the case of the present embodiment, information on physical quantities and power equations in the current target system is collected. In this procedure, variables are also initialized at the same time. Next, in step 302, the above-described constraints and their values are set. Next, in step 303, a coefficient matrix of (Equation 3) is created. In this case, the first derivative and second derivative of each variable are obtained in advance from (Equation 3), and the elements of the coefficient matrix are calculated by substituting the values of the above variables. Next, in step 304, the value on the right side of (Equation 3) is obtained by substituting the variable x into the power equation. When the above calculation is completed, a decomposition calculation is performed in step 305 to obtain a solution Δx. If this value is smaller than a preset threshold value compared with the value one time before the repetitive calculation in step 306, it is regarded as convergence and the process proceeds to step 307. If not, the procedure returns to step 303 and the calculation is repeated. After the convergence is determined in step 306, it is determined whether the solution obtained in step 307 does not violate the constraint conditions. If there is no violation, the process ends. If there is a violation, the violated variable is multiplied by a penalty coefficient α other than 0.0, and the process returns to step 303 to continue the calculation.
[0023]
A specific example of the embodiment of the method for determining the specific equipment described above will be described below with reference to FIG. Here, there is a case where a loosely-coupled power system control device existing in an arbitrary region needs a system state and an equipment operation state in another region, and also requires an operation such as system switching with another region system. In this case, in step 401 of FIG. 4, it is determined based on the information of the data collection device 102 whether or not the equipment is connected to the area where the control is to be performed (hereinafter referred to as the own area) or whether the equipment in the own area can be separated into other areas. To explore. Next, in step 402, it is determined whether there is a control facility with another area. If coordination with another area cannot be made, it is determined in step 403 whether control can be performed using the control equipment in the own area. If control is possible, the corresponding equipment is determined in the same manner as in the first embodiment. If there is no applicable equipment, the equipment in the own system that deteriorates the condition evaluation index is detected, and the applicable equipment is separated from the regional system. If it is possible in step 402 to cooperate with another area, in step 406 the cooperable facilities are set so that they can be used for the formulation used in step 407 and subsequent steps. Thereafter, in steps 407, 408, and 409, a solution is obtained by using the optimization method shown in FIG. 3. When a solution for the equipment operation is obtained, the operation of the corresponding equipment is issued to the control command device 106 in step 410. I do. If not, the process returns to step 403 to execute the above-described processing.
[0024]
Next, an example using a specific state evaluation index in this embodiment will be described. If the voltage unbalance is defined as an unbalance voltage ratio that occurs when a balanced voltage is applied as an evaluation index, the objective function is the sum of squares of the voltage unbalance in each bus in the regional system, and the control variable, Δx on the left side of Equation 3 is the active / reactive power injection amount in each phase of each node, and the constraint condition is the upper and lower limits of equipment for eliminating imbalance, for example, the upper and lower limits of phase adjustment equipment, or the upper and lower limits of power flow of transmission lines. And the upper and lower limits of the voltage of each bus. The numerical value corresponding to the right side of Expression 3 uses the voltage of each phase of each node. The coefficient matrix is created based on the power equation. When frequency fluctuation is used as the evaluation index, the objective function is to minimize the square of the frequency change in the regional system and the square of the difference from the reference frequency. Using the power output adjustment value, information indicating the parallel sequence of generators, information on transmission to other areas, etc., as constraints, the upper and lower limits of the facilities of each generator, the output change rate, the upper and lower limits of the power flow of the transmission line in the system And so on. When the short-circuit current is set as the evaluation index, the objective function is to minimize the square of the difference between the rated short-circuit capacity of the transformer at the interconnection point with another area and the calculated short-circuit capacity. The x on the left side of Expression 3 corresponds to the use / stop / switch of the transformer, the use / stop / switch of the transmission line, the system division, and the evaluation index is bus line division information or the like. Next, the constraint conditions are the upper and lower limits of equipment and the stability index. When the voltage stability is set as an evaluation index, the square of the difference between the active power increase margin obtained when the objective function is created and the total sum of the current active power loads is maximized. X on the left side of Equation 3 corresponds to a change in the magnitude of the voltage, a change in the phase angle, a change in the tap ratio of the transformer, a change in the terminal voltage value of the AVR generator, and the input amount of the phase adjustment equipment. And the like. The constraint conditions are the upper and lower limits of the equipment and the upper and lower limits of the bus voltage. Next, when the steady state stability is set as the evaluation index, the objective function is to minimize the sum of the phase difference angles. What corresponds to x on the left side of Equation 3 is a change in the generator active power output, parallel sequence information of the generator, power supply restriction information, and the like. The constraint conditions are the upper and lower limits of the equipment and the upper and lower limits of the bus voltage.
[0025]
An example using the schematic diagram of the loosely-coupled power system control device described above will be described below using model systems shown in FIGS. 5, 6, 7, and 8. FIG. 5 shows a model of a loosely coupled power system. Reference numerals 501, 502, and 503 correspond to the sub-systems that have been called regions. Reference numerals 411, 412, 413, 414, 415, 416, 417, and 418 denote transmission lines. Thick lines indicate transmission lines in use, and thin lines indicate transmission lines stopped in use. In addition, a circle indicates a substation, and it is assumed that a plurality of power generation devices and load devices exist in this substation. It is also assumed that each substation is connected by a transformer. In the embodiment of FIG. 5, a case is considered in which the number of objective functions is limited to one for convenience of description, and here, a harmonic is used as a state evaluation index. In the figure, it is assumed that a large harmonic voltage distortion has occurred at the substations 421, 422, and 423 indicated by ●. In the area 402, it is assumed that no harmonic is generated in other substations. Here, it is an object to reduce the harmonics in the excess area by exchanging the capacitor in the area which is a factor of generation of the harmonics. In FIG. 4, at 421, the harmonic distortion amount exceeds the allowable specified value of 5% by 1%, at 422, it exceeds the allowable specified value by 1%, and at 423, the state exceeds the allowable specified value by 3%. I do. It is also assumed that the harmonic distortion in the area 401 is 3.5% smaller than the allowable value and less than the allowable value in the area 403. The reference value is set to 0%. If the objective function in this case is the sum of squares of the deviation from the reference value, the objective function is 1.5 * 1.5 + 9.0 * 9.0 + 0.5 * 0.5 = 83.5 in the state of FIG. In this state, since the harmonic distortion in the area 502 is 9%, the operation of the switch that minimizes the objective function in the adjacent area system is determined while eliminating this violation. It is assumed that candidates for switching 423 to the region 401 and switching 421 and 422 to the region 403 and candidates for switching 423 to the region 403 and 421 and 422 to the region 401 were found when solving the optimization problem. I do. Since the smaller of the objective function is selected from the two candidates, the objective function is calculated. In the case of the first candidate, 3.5 * 3.5 + 4.0 * 4.0 + 3.5 * 3.5. = 40.5, and in the case of the second candidate, 4.5 * 4.5 + 4.0 * 4.0 + 2.5 * 2.5 = 42.5, and the first candidate is selected as the operation. The optimization process shown in FIG. 3 is briefly described above. FIG. 6 shows an example of a result of performing a control operation according to this result. The transmission lines 412, 415, and 416 that have been stopped until now are connected, and the transmission lines 418, 414, and 417 are stopped to switch the system configuration. Each area is changed as shown in FIG. When the system switching with another area is performed in this way, control information is transmitted to the other area through the data collection device 102 or received from the other area.
[0026]
Next, an embodiment in which the state evaluation index is voltage stability will be described with reference to FIGS. The meanings of the thick lines, thin lines, and white circles in FIG. 7 are the same as those in FIG. Reference numerals 631, 634, and 635 denote phase adjustment equipment serving as voltage adjusting devices, and reference numerals 632 and 633 denote generators that control AVR terminal voltages. The objective function of the voltage stability is defined as the sum of squares of the difference between the current load of 100% and the limit load that can be obtained from the PV curve. Further, it is assumed that the minimum required value of the voltage stability is + 6% from the demand amount at the present time, and is assumed to be + 7% in the area 701, + 3% in the area 702, and + 10% in the area 703. That is, in the area 702, it is necessary to increase the voltage stability. At this time, it is assumed that the AVR generator terminal voltage has a margin of 1% increase in the region 702, the transformer tap has no margin for increase, and the phase adjustment facility has no margin for increase in the region 702. In the area 701, the AVR generator terminal voltage allowance (device 732) that can be connected to another area is 0.5%, the rise margin of the transformer tap is 0%, and the phase adjustment facility rise margin is 1 (device 731). In the area 703, the AVR generator terminal voltage allowance that can be connected to other areas is 1 (equipment 733)%, the transformer tap rise allowance is 0%, and the phase adjustment facility rise allowance is 1% ( Assume that there are devices 735) and 4% (device 734). Assuming that the objective function is the sum of squares of the difference between the marginal load and the current load when a margin of 6% can be maintained, the voltage stability can be obtained by using 631, 632, 634, and 635 for the area 702 by the optimization method represented in FIG. Suppose that the result that the shortage is resolved is obtained. In this case, the area 702 operates the transmission lines 712, 713, 715, and 716 in cooperation with the areas 701 and 703, and stops the transmission lines 717 and 718. FIG. 8 shows the result after the control. In the above-described embodiments, the objective function is performed using one type of state evaluation index for convenience of description, but it is also possible to perform optimization calculation by combining any type of state evaluation index. . It is also possible to perform optimization calculation using one type of state evaluation index, and to perform this calculation more times after changing the state evaluation index based on the result.
[0027]
Although the control operation so far uses an optimization method using the Newton method, it can also be realized using an optimization method using a mathematical programming method such as a linear programming method.
[0028]
As described above, the first embodiment of the loosely-coupled power system control apparatus of the present invention is used to flexibly change the control range while observing the system status, so that the voltage stability, which has not been considered at the same time, Control of a power system that satisfies the trade-off of a plurality of indices such as harmonic countermeasures, that is, stable power supply becomes possible. This makes it possible to keep the flow of electricity in the power system in a certain direction as a secondary effect, so it is necessary to solve various problems caused by the introduction of distributed power sources, especially the problem represented by the reverse power flow problem. It is possible to reduce the required investment. The effect of introducing this device is that, compared with the conventional method of controlling all energy supply and demand imbalances generated in each region using higher-level equipment, the local system autonomously uses the state evaluation index. Therefore, the effect of reducing the load on the collective control burden on the host system can be expected.
[0029]
The second embodiment of the loosely-coupled power system control device of the present invention solves the control decision performed by the first embodiment based on the index as an optimization problem, whereas a predetermined flowchart is used. This is a method of executing control while coordinating with other areas based on the above. This second embodiment will be described with reference to FIGS. In the present embodiment, it is assumed that a monitoring point of a physical quantity is provided, and the monitoring point is a power flow value of a transmission line connecting each area. Also, assuming a power supply cost, the order is determined in advance. First, two cases will be described: (1) the power generation amount of the distributed power source in the region is smaller than the load amount in the region, and (2) the power generation amount of the distributed power source in the region is larger than the load amount in the region. . The case 1) will be described with reference to FIG. If the power generation amount is insufficient as a result of comparing the power generation amount and the load amount in the own area in the procedure 901, this is a case where it is necessary to procure power from another adjacent area into the own area. In that case, first, in step 902, it is determined whether adjustment of the IPP in the own area is possible. If this is possible, in step 903, an output fluctuation request is made to the IPP generator in the own system to secure the supply and demand balance in the own system. If adjustment of the IPP is impossible, it is detected in step 904 whether or not there is another area connected within the own area. Further, in step 905, information on the other area is obtained as to whether or not the power interchange is possible in the adjacent other area, and whether or not the power interchange is possible is determined. If power cannot be supplied from another adjacent area, the process proceeds to step 907. If power can be supplied from another adjacent area, power generation is procured in step 906. On the other hand, if another area that satisfies the condition is not found in step 905, a part of the load in the own area or step 907 is maintained in order to keep the monitoring point tide flow constant in cooperation with the other area. Explore other areas where everything is acceptable. If this is possible, in step 908 the switch in the own area is operated to disconnect the load and connect to another area. If this is not possible, the load is rejected in step 909 so that the values of the monitoring points become the set values in descending order of the priority set in the database 103 for the loads existing in the local area. .
[0030]
Next, the case (2) will be described with reference to FIG. If the amount of load is insufficient as a result of comparing the amount of power generation and the amount of load in the own area in step 1001, this means that power must be procured from the own area to another adjacent area. In that case, first, in step 1002, it is determined whether adjustment of the IPP in the own area is possible. If this is possible, in step 1003, an output fluctuation request is made to the IPP generator in the own system to secure the supply and demand balance in the own system. If it is impossible to adjust the IPP, it is detected in step 1004 whether there is another area connected within the own area. Further, in step 1005, information on the other area is obtained as to whether or not the power interchange is possible to the adjacent other area, and whether or not it is possible is determined. If it is impossible to supply power to another adjacent area, the process proceeds to step 1007. If power can be supplied to another adjacent area, the power generation amount is sent to the adjacent area in step 1006. On the other hand, if another area that satisfies the conditions is not found in step 1005, a part of the power generation facilities in the own area will be kept in step 1007 in order to keep the tide flow at the monitoring point constant in cooperation with the other area. Or explore other areas where everything is acceptable. If this is possible, in step 1008, the switch in the own area is operated to disconnect the power generation equipment and connect to another area. If this is not possible, the power supply is restricted in step 1009 so that the values of the monitoring points become the set values in descending order of the priority set in the database 103 for the loads existing in the local area. .
[0031]
In the above-described embodiment, the order of control is the order of IPP, inter-region power interchange, load switching, power control, and load control in advance. However, this order may be any other order in consideration of the control execution situation. It may be a combination.
[0032]
Using the above-described second embodiment of the loosely-coupled power system controller of the present invention, the control range is flexibly changed while observing the system condition, so that the voltage stability and the harmonics which have not been considered at the same time are considered. Control of the power system that satisfies the trade-off of a plurality of indices such as countermeasures, that is, stable power supply becomes possible. In this embodiment, unlike the first embodiment, the optimization calculation is not performed, so that the control solution can be reliably obtained, and the reliability of the control is increased. In particular, the second embodiment is effective when performing the same effect as the first embodiment by real-time control.
[0033]
The third embodiment is an example in which the state evaluation by the state evaluation device in the first embodiment is performed over a future time section. In the case of future time section, future system prediction is required. This method predicts the future state of the system based on the past history data stored in the database 103 and the current state of the system estimated in the first embodiment, and performs various types of regional system at the future time. A method of calculating the physical quantity and the state monitoring index is suitable. This method is described in detail in the following known examples.
[0034]
Nakajima, Okubo, Matsumoto, Ishida, Tamura, Development of next-hour power flow prediction (DPF) system for the next Central Power Distribution Center. IEEJ National Convention, 1995, 1291.
[0035]
By using the above-described third embodiment of the loosely-coupled power system control device of the present invention to perform system control using future prediction, stable power supply can be achieved even when the system state suddenly changes. Further, since the third embodiment can be used for system operation planning, a compensation facility for solving the problems caused by the introduction of the distributed power supply in advance while looking at the plan for introducing the distributed power supply in the future. Since it can be used for drafting an introduction plan, efficient capital investment at a future time will be possible.
[0036]
【The invention's effect】
As described above, in the loosely-coupled power system control device of the present invention, a data collection device that collects physical quantities representing characteristics of a power system in a local system from the local system, a database that stores information collected by the data collection device, A state evaluation device that evaluates the state of the local system based on the information of the data collection device and the database, and a state evaluation result for each region and an objective function of the power system that is created based on the physical quantity are compared with other region systems. A control calculation device for generating a switch operation command signal for cooperative optimization; and a control command device for issuing a result of calculation by the control calculation device to a control facility in the regional system and a control facility in another regional system. Therefore, it is possible to always realize stable power supply in the entire system while considering a trade-off between a plurality of objective functions.
[Brief description of the drawings]
FIG. 1 is a drawing showing a typical embodiment of the present invention.
FIG. 2 shows an example of data storage in a database.
FIG. 3 is a flowchart in the case of solving using an optimization technique.
FIG. 4 is a flowchart in the case of executing control while cooperating with another area.
FIG. 5 is a diagram illustrating a model example.
FIG. 6 is a diagram illustrating a model example.
FIG. 7 is a diagram illustrating a model example.
FIG. 8 is a diagram illustrating a model example.
FIG. 9 is a diagram showing a case where the amount of power generation is excessive in the embodiment using the logic of the control calculation device.
FIG. 10 is a diagram showing a case where the load amount is excessive in the embodiment using the logic of the control calculation device.
[Explanation of symbols]
101: Power system to be controlled 102: Data collection device 103: Database 104: State evaluation device 105: Control variable determination device 106: Control calculation device 107: Control command device 111, 112, 113 Regional system, 151 to 160 ... Switch, 201 ... Example of storage of equipment database, 202 ... Example of storage of database related to physical quantity in system, 203 ... Example of database related to controllable equipment, 204 ... Example of database related to monitoring point, 205 .., An example of a database relating to the execution priority of electric load control, 301: necessary data reading procedure, 302: constraint condition setting procedure, 303: coefficient matrix creation procedure, 304: right side creation procedure, 305: decomposition substitution calculation procedure, 306: convergence Judgment procedure, 307: constraint violation judgment procedure, 308: penalty Fixed procedure, 401: equipment search procedure in other areas, 402: equipment existence procedure, 403: equipment controllability determination procedure, 404: equipment shutdown procedure, 405: equipment control procedure, 406: equipment storage procedure, 407: formulation of the Newton method Procedure, 408: solution obtaining procedure, 409: calculated solution existence determining procedure, 410: system operation command procedure, 501, 502, 503, 504, 505, 701, 702, 703: area, 511, 512, 513, 514 515, 516, 517, 711, 712, 713, 714, 715, 716: power transmission equipment, 521, 522, 523, 721, 722, 723: substation, 731, 732, 733, 733, 735: voltage reactive power adjustment Equipment, 901, 1001... Supply / demand balance determination procedure in the local system, 902, 1002... IPP output change determination procedure 903, 1003 ... IPP output adjustment procedure, 904, 1004 ... adjacent area detection procedure, 905, 1005 ... power supply determination procedure, 906, 1006 ... power generation interchange procedure, 907, 1007 ... load separation possibility determination procedure, 908, 1008 ... Load switching procedure, 909: load shedding procedure, 1009: power control execution procedure.

Claims (2)

In a power system in which an arbitrary number of energy consuming facilities, an arbitrary number of energy generation facilities, and a plurality of regional systems including power transmission and distribution facilities are connected by power transmission facilities via interconnection switches, the A data collection device that collects physical quantities representing characteristics from the local system, a database that stores information collected by the data collection device, and a state evaluation that evaluates the state of the local system based on the information of the data collection device and the database Voltage imbalance, harmonic generation, frequency fluctuation, load characteristics in the system area, short-circuit current, voltage stability, transient stability of the power system created based on the status evaluation results for each device and each area and the physical quantities every time, the power generation cost, control computation device for generating a switch operation command signal to optimize cooperation with other regions lineage as an objective function to any of a plurality of indices of equipment operating costs Loosely coupled power system control apparatus having a control command system which performs command calculation result in the control computing unit to the control equipment of the control equipment and other areas strains in said area system. In a power system in which an arbitrary number of energy consuming facilities, an arbitrary number of energy generation facilities, and a plurality of regional systems including power transmission and distribution facilities are connected by power transmission facilities via interconnection switches, the A data collection device that collects physical quantities representing features from the local system, a database that stores information collected by the data collection device, and a state evaluation that evaluates the state of the local system based on the information of the data collection device and the database From the equipment, past history data and the state evaluation equipment, the system state and voltage imbalance, harmonic generation, frequency fluctuation, load characteristics in the system area, short-circuit current, voltage stability, transient stability at the future time , Power generation cost, or facility operation cost, and predicts the power system voltage imbalance, high A switch that optimizes in coordination with other regional systems as an objective function of wave generation, frequency fluctuation, load characteristics in the system area, short-circuit current, voltage stability, transient stability, power generation cost, and facility operation cost A loosely-coupled power system control device comprising: a control calculation device that generates an operation command signal; and a control command device that commands a calculation result obtained by the control calculation device to a control facility in the regional system and a control facility in another regional system.

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