JP3877984B2

JP3877984B2 - Loss measurement method of tidal current control device and its utilization method

Info

Publication number: JP3877984B2
Application number: JP2001220818A
Authority: JP
Inventors: 博雄小西; 重幸杉本; 重明小川
Original assignee: Chubu Electric Power Co Inc; Hitachi Ltd
Current assignee: Chubu Electric Power Co Inc; Hitachi Ltd
Priority date: 2001-07-23
Filing date: 2001-07-23
Publication date: 2007-02-07
Anticipated expiration: 2021-07-23
Also published as: JP2003032895A

Description

【０００１】
【発明の属する技術分野】
本発明は潮流制御装置の損失測定方法と、その損失測定結果を利用して潮流制御のための電力設定や電力コスト決定やコスト評価を行う利用方法とに関する。
【０００２】
【従来の技術】
電力の自由化に伴いＩＰＰや分散電源等の卸売りや小売り電力業者が電力系統に参入しつつある。このように電力系統に多くの電力業者が入ってくると、電力の潮流制御が必要になるので、潮流制御装置の導入が検討されている。
【０００３】
このような潮流制御装置には、これまで系統安定化装置として開発されてきたＦＡＣＴＳ等のパワーエレクトロニクス技術を使った装置が、制御の容易さ，高速性，安定度向上の面から適用できる。
【０００４】
非同期連系システムや直流送電システムは送電端で交流を直流に変換し、直接または直流送電線を介して負荷地で直流を交流に変換して負荷に所定の電力を供給する。また、高速移相調整器(ＵＰＦＣ：Unified Power Flow Controller）はコンバータとインバータとを備え、送電線に直列に挿入された直列変圧器の印加電圧の位相と大きさとを制御し、潮流制御する。これら潮流制御装置は常時潮流制御として使用するので常時の装置損失が少ないことが必要である。また、これら装置の送電損失を、電力指令所，ＩＳＯ，電力託送会社，発電会社等が送電電力設定や料金支払の面の必要性から把握する必要がある。
【０００５】
パワーエレクトロニクス技術を適用した非同期連系システム，直流送電システム，ＵＰＦＣなどの前記潮流制御装置は、交流を直流に変換するコンバータと直流を交流に変換するインバータとを備えていて、潮流制御装置の損失は交直変換器や交流系統に連系する変換用変圧器等によって主に生じる。
【０００６】
従来はこの電力損失を各装置の抵抗分と流れる電流から計算によって求めたり、入力端の電力と出力端の電力とを両方検出しその差からを求めていた。
【０００７】
【発明が解決しようとする課題】
前記の各装置の抵抗分と流れる電流から計算によって電力損失を求める方法では、潮流制御装置の交直変換器から発生する高調波による電力損失を求めることができなかった。また、前記従来技術の入力電力と出力電力を検出しその差から損失を求める方法では、入力端と出力端の両方に精度が同等な電力検出器が必要であり、しかも電力検出器の検出データを相手端に送る必要がある。
【０００８】
本発明の目的は、潮流制御装置の電力損失を入力端または出力端片端の電力測定により検出する損失測定方法の提供である。
【０００９】
また、本発明の別の目的は、検出した潮流制御装置の電力損失情報を、インターネットや会社内のイントラネット等の汎用の通信装置を介して電力制御所，ＩＳＯ，電力託送業者，ＩＰＰ，分散電源供給会社等に配送し、電力制御やコストを評価決定する方法の提供である。
【００１０】
【課題を解決するための手段】
本発明の潮流測定装置の損失測定方法は、非同期連系装置，直流送電システムやＵＰＦＣのコンバータ（順変換器）側が直流電圧一定制御を行い、相手端のインバータ（逆変換器）側が電力一定制御を行っていて、順変換器は直流電圧を一定に保つために、逆変換器で設定された電力よりシステムトータルの損失分だけ大きい電力を取り込むように動作をするので、順変換器の入力電力の測定値から負荷に送電する電力設定値を差し引くことにより高調波損失を含むシステムの全電力損失を求める。
【００１１】
また、本発明の潮流測定装置の損失測定方法は、順変換器側が電力一定制御を行い、逆変換器側が直流電圧一定制御を行っていて、逆変換器が順変換器の出力よりもシステムトータル損失分だけ小さい電力しか出力できないので、直流電圧一定制御を行う逆変換器側に出力電力の測定値を求めて、負荷に送電する電力設定値から出力電力の測定値を差し引くことにより高調波損失を含むシステムの全電力損失を求める。
【００１２】
上記のようにして測定した電力損失情報をインターネットを介して電力制御所，発電会社，託送会社，ＩＳＯ等に送り、潮流制御装置の損失を含めた電力ディーリング，運用やコスト評価等を行う。
【００１３】
【発明の実施の形態】
以下、本発明の詳細を図面を用いて説明する。
【００１４】
（実施例１）
本実施例を適用した非同期連系システム、または直流送電システムを説明する。図１に本実施例の直流送電システムを示す。本実施例では、潮流が図１中左から右に流れる場合を説明する。図１中の符号１４，２４は交流系統、１３，２３は交流母線、３は２つの交流系統を連系する交流連系線、１はＩＧＢＴ等の自己消弧素子で構成する、交流を直流に変換する自励式変換器の順変換器（コンバータ）、２は直流を交流に変換する自励式変換器の逆変換器（インバータ）、１１，２１は直流電圧を平滑するための直流コンデンサ、１２，２２は変換用変圧器、３０ａ，３０ｂは直流送電線である。符号１００は潮流制御装置の潮流電力を指令する潮流指令所、２００は順変換器１を制御する制御装置、３００は逆変換器２を制御する制御装置である。符号２０１は順変換器１に流れる電流を検出する交流電流変成器、２０２は交流電圧変成器、２０３は順変換器１の入力電力を検出する電力変成器である。符号４００は全系統の潮流を制御する全電力指令所（制御所）、５００はＩＳＯ，電力託送業者等、６００は汎用のインターネットやイントラネット等の通信ネットワークである。
【００１５】
なお、非同期連系システムでは直流送電線３０ａ，３０ｂがない他は、図１に示す直流送電システムと同じである。
【００１６】
まず図１の構成で交流系統１４と２４との間の潮流が任意に制御できることを説明する。交流系統１４と２４間の潮流は交流系統１４と２４の電圧の位相差を調整して行う。交流系統２４に対して交流系統１４の位相をθ進めると、下式のようになる。
【００１７】
Ｐ＝Ｖ１・Ｖ２・sin(θ）／Ｘ
ここに、Ｖ１は交流系統１４の電圧、Ｖ２は交流系統２４の電圧、Ｘは交流系統１４と２４を連系する送電線のインピーダンス、Ｐは電力である。
【００１８】
しかし直流連系装置がある場合には交流系統１４と２４との位相差に関係なく直流連系装置の電力設定値に応じて任意の方向に、且つ高速に電力を流すことができる。ただし、潮流連系装置により潮流が流れると、交流系統の位相差が変化するので、過渡的に潮流は潮流制御装置によって調整できるが、定常的には交流系統間の位相差を調整しないと潮流は変わらない。
【００１９】
次に本実施例で潮流制御装置の損失が順変換器１側の入力電力のみを測定すれば求まることを図２を用いて説明する。図２は直流連系装置の順変換器と逆変換器の有効電力と直流電圧の特性の関係を示す。順変換器と逆変換器に電力一定制御特性と直流電圧一定制御特性とを持たせ、順変換器の電力設定値を変換器容量一杯の値に設定値し、直流電圧設定値を規定の値Ｖｄｒｅｆに設定する。逆変換器の直流電圧設定値は順変換器の設定値よりも余裕を持った値、例えば定格の１０％程度低い値に設定し、電力設定値を負荷が必要とする値Ｐｄｒｅｆに設定する。
【００２０】
このように設定したときの動作点は図２の順変換器特性と逆変換器特性の交点となる。前記特性を持たせると、順変換器の入力電力が、直流電圧を一定にするために逆変換器に設定された電力量よりも潮流制御装置の損失分だけ大きい電力となる。言い換えると、順変換器の電力がこの値よりも小さいと直流電圧が規定値よりも低下し、逆に大きいと高くなり、等しいところで規定の電圧となる。
【００２１】
従って直流電圧を制御する変換器の入力電力のみを測定して潮流制御装置の高調波損失を含めた全損失を求めることができる。すなわち図３に示すように入力電力から、負荷の電力設定値を差し引くことにより全損失が求まる。図３で、電力測定値と負荷電力指令値との差の絶対値を計算している理由は、潮流制御装置の潮流方向により電力測定値に損失が上記のようにプラスで出る場合と後述するようにマイナスで出る場合とがあるためである。
【００２２】
上記で求めた電力損失情報をインターネット，イントラネット等、汎用の通信装置により全電力指令所や電力託送業者やＩＳＯ等に送ることによって、全系統の潮流のバランスを取ることができると共に、電力損失を考慮した負荷への電力送電や送電コストの計算が可能となる。
【００２３】
図４に具体的に損失を考えた電力指令値の設定を示す。電力指令値は負荷系統に必要な電力に潮流制御装置の損失を加えた電力指令値を潮流制御装置の電力指令値とすれば良いし、また送電側の発電電力の設定値にすれば良い。この機能を全電力指令所が備えることが要求される。
【００２４】
一方コストに関しては、潮流条件下での潮流制御装置の損失量が求まるので、損失電力量を発電コストに上乗せするか、送電コストに上乗せするか、または受電側コストに上乗せするか、何れかにするかが決まれば電力単価量をもとに決定できる。損失を考慮したコスト評価は専用のプログラムを使って電力託送業者やＩＳＯ，発電所等で計算できる。
【００２５】
図５に図２に示した順変換器と逆変換器の制御特性を実現する自励式変換器の一般的な制御ブロックを示す。符号２１１は有効電力一定制御回路、２１２は直流電圧一定制御回路、２１３は信号選訳回路で図２に示した各変換器特性となるように有効電力一定制御回路と直流電圧一定制御回路の出力信号が選択され、この信号が自励式変換器の交流出力の有効電力や直流出力または入力の直流電圧を規定値（設定値）にするための交流出力電圧の位相を制御する。符号２１４は無効電力一定制御回路で自励式変換器の出力電圧の大きさを制御して系統に流れる無効電力を制御する。符号２１５は有効電力と無効電力を非干渉制御するための変換器制御部を表す。一般に使われている構成制御ブロックを図６に示す。
【００２６】
図６で、符号２１５ａは上位にある有効電力制御回路または直流電圧制御回路の有効電力または直流電圧を規定値に制御するための指令値を受け、交流電流からｄｑ変換によって取り出された実電流をこの指令値に制御するための実電流(ｄ軸電流)制御回路、２１５ｂは上位にある無効電力制御回路の無効電力を規定値に制御するための指令値を受け、交流電流からｄｑ変換によって取り出された虚電流をこの指令値に制御するための虚電流(ｑ軸電流)制御回路、ＩＸは変換用変圧器のインピーダンスを乗じることを表し、実電流または虚電流の該インピーダンスドロップによる干渉を打消して実電流と虚電流の非干渉制御を実現する。ここでｄｑ変換は、系統の電圧と変換器出力電圧との位相差βの正弦及び余弦の関数値を使って行われる。符号２１５ｅはｄｑ軸成分を固定座標のαβ座標系に座標変換する２軸逆変換回路、２１５ｆはαβ座標系を元の３相回転座標系の交流電圧基準値Ｖａ２１，Ｖｂ２１，Ｖｃ２１に変換する３相変換回路、２１５ｇはパルスキャリアとなる三角波とこの交流電圧基準値から自励式変換器のＰＷＭパルスを作成するＰＷＭパルス発生回路である。この回路構成により実電流（有効電力）と虚電流（無効電力）とを独立に非干渉で制御できる。
【００２７】
（実施例２）
実施例１では潮流の方向を図中左から右に流れる場合を説明した。本実施例では、潮流方向が実施例１と逆に変わり、順変換器が逆変換器となり、逆変換器が順変換器となった場合であって、順変換器側で電力一定制御を行い、逆変換器側で直流電圧一定制御を行う。この場合、逆変換器の出力は順変換器の出力よりもシステムトータル損失分だけ小さい出力しか出力できなくなる。これは損失分だけ小さい出力より、多くの電力を出力すると直流電圧が低下し、損失分だけ小さい出力よりさらに少ない電力を出力すると直流電圧が上昇するので、ちょうど損失分を差し引いた電力で直流電圧が規定値となる動作となる。従って直流電圧一定制御を行う逆変換器側で出力電力を測定すれば、順変換器の電力設定値からこの測定値を差し引くことにより高調波損失を含めたシステムの全損失を求めることができる。
【００２８】
求めた電力損失情報を上記と同様にインターネットやイントラネットを介して全電力制御所，発電会社，託送会社，ＩＳＯ等に送り、潮流制御装置の損失を含めた電力ディーリング，運用，コスト決定・評価等ができる。
【００２９】
（実施例３）
図７に本実施例を示す。図１では自励式変換器を用いた潮流制御装置であったが、本実施例は他励式変換器を用いた非同期連系システムまたは直流送電システムによる潮流制御装置である。図７の構成により２つの交流系統間の潮流が制御できることは図１と同様である。
【００３０】
図７において、潮流の方向を図中左から右に流れる場合を説明する。図７で、符号３はサイリスタ等のオン時点のみを制御できる素子で構成される他励式変換器の順変換器（コンバータ）、４は他励式変換器の逆変換器（インバーター）、３１，３２は直流電流を平滑する直流リアクトル、３０１は逆変換器１に流れる電流を検出する交流電流変成器、３０２は交流電圧変成器、３０３は逆変換器２の出力電力を検出する電力変成器である。
【００３１】
本実施例では順変換器で有効電力を制御し、逆変換器で直流電圧を一定に制御する。この時の順変換器と逆変換器の直流電流と直流電圧の関係を図８に示す。順変換器には負荷に必要な有効電力を送電するための直流電流設定値Ｉｄｒｅｆを与え、直流電流一定制御特性を持たせる。一方、逆変換器には直流電圧を規定の値Ｖｄｒｅｆに保つための直流電圧一定制御特性と、交流電圧低下時のバックアップ運転として順変換器の電流設定値Ｉｄｒｅｆよりも電流マージン△Ｉｄだけ小さい値に電流設定値を持った直流電流一定制御特性を持たせる。
【００３２】
このような特性を順変換器と逆変換器に持たせたときの動作点は２つの特性の交点となる。順変換器で負荷に必要な有効電力を一定に保つ運転を行うが、逆変換器では直流電圧一定制御を行っているので、逆変換器側で有効電力を測定すると、損失分だけ小さい電力が測定されることになる。逆変換器でこれよりも大きな電力が測定されるならば直流電圧が規定値よりも低下するであろうし、少ない電力が測定されると直流電圧が高くなる。従って、直流電圧が規定値に保たれるときには逆変換器側で測定される出力電力は、順変換器側の電力設定値よりも損失分だけ小さくなる。逆変換器で所定の有効電力を取り出そうとする場合は、順変換器の電力設定値（直流電流設定値×直流電圧）をシステムの全ロス分だけ大きな電力設定値とする必要がある。
【００３３】
直流電圧一定制御を行っている逆変換器側の出力電力のみを測定し、電力設定値からこの測定値を引くことにより、高調波損失を含めた潮流制御システムの全損失が求められることになる。求められた損失の情報をインターネット等の通信装置を用いて発電会社，託送会社，ＩＳＯ等に送り、潮流制御装置の損失を含めた電力ディーリング，運用やコスト評価等ができる。
【００３４】
（実施例４）
図９に本実施例を示す。図１では自励式変換器を用いた潮流制御装置、図７では他励式変換器を用いた潮流制御装置を示したが、本実施例では送電線に直列に挿入された直列変圧器の電圧の位相を変化させることによって線路に流れる潮流を制御する。
【００３５】
その電圧位相は図１と同じ自励式変換器の順変換器と逆変換器によって作り出される。これまでの図と同じ番号のものは同じ機能を表すので異なった新しいものについてのみ説明する。図９の符号２９は送電線に直列に挿入される直列変圧器で、変圧器の一次側は逆変換器２によって励磁される。
【００３６】
逆変換器の出力電圧の大きさと位相を制御して有効分及び無効分の潮流を制御できることが知られている。本実施例でも順変換器１で直流電圧を一定に制御し、逆変換器２で有効電力を一定に制御する。前記図１の説明と同様に、順変換器に流れる電流と電圧から、ここに流れる有効電力を求めると、この値はシステムの損失分だけ大きい電力が測定される。従って電力設定値を差し引くことによって高調波損失を含めたシステムの全電力損失を求めることができる。
【００３７】
求めた電力損失データはインターネット等の通信装置を用いて発電会社，託送会社，ＩＳＯ等に送り、潮流制御装置の損失を含めた電力ディーリング，運用やコスト評価等できる。
【００３８】
【発明の効果】
直流電圧一定制御を行う変換器に流れる有効電力のみを測定して潮流制御装置の高調波損失を含めた全システム損失を求められる。またこの損失をインターネット，イントラネット等の汎用の低コストな通信装置を介して発電会社，電力制御所，電力託送会社，ＩＳＯ等に送り、潮流制御装置の損失を含めた電力ディーリング，運用やコスト評価等できる。
【図面の簡単な説明】
【図１】実施例１の潮流制御装置の損失の測定方法と利用方法の説明図である。
【図２】実施例１の自励式変換器の有効電力と直流電圧の特性を示す図である。
【図３】実施例１の損失測定方法の説明図である。
【図４】実施例１の電力指令値作成方法の説明図である。
【図５】実施例１の自励式変換器の制御部ブロック図である。
【図６】実施例１の自励式変換器の変換器制御部ブロック図である。
【図７】実施例３の潮流制御装置の損失の測定方法と利用方法の説明図である。
【図８】実施例３の他励式変換器の直流電流と直流電圧の特性を示す図である。
【図９】実施例４の潮流制御装置の損失の測定方法と利用方法の説明図である。
【符号の説明】
１…自励式変換器の順変換器（コンバータ）、２…自励式変換器の逆変換器
（インバータ）、３…交流連系線、１１，２１…直流コンデンサ、１２，２２…変換用変圧器、１３，２３…交流母線、１４，２４…交流系統、２９…直列変圧器、３０ａ，３０ｂ…直流送電線、１００…潮流指令所、２００…制御装置１、２０１，３０１…交流電流変成器、２０２，３０２…交流電圧変成器、２０３…電力変成器、２１１…有効電力一定制御回路、２１２…直流電圧一定制御回路、２１３…信号選択回路、２１４…無効電力一定制御回路、２１５…変換器制御部、２１５ａ…実電流（ｄ軸電流）制御回路、２１５ｂ…虚電流（ｑ軸電流）制御回路、２１５ｅ…２軸逆変換回路、２１５ｆ…３相変換回路、２１５ｇ…ＰＷＭパルス発生回路、３００…制御装置２、３０３…電力変成器、４００…全電力指令所、５００…ＩＳＯ，電力託送業者等、６００…通信ネットワーク。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a loss measurement method for a power flow control device and a use method for performing power setting, power cost determination, and cost evaluation for power flow control using the loss measurement result.
[0002]
[Prior art]
With the liberalization of electric power, wholesale and retail electric power companies such as IPP and distributed power supply are entering the electric power system. In this way, when many electric power companies enter the power system, power flow control is required, and therefore introduction of a power flow control device is being studied.
[0003]
A device using power electronics technology such as FACTS, which has been developed as a system stabilizing device, can be applied to such a power flow control device in terms of ease of control, high speed, and stability improvement.
[0004]
An asynchronous interconnection system and a DC power transmission system convert alternating current into direct current at a power transmission end, and convert direct current into alternating current directly or via a direct current transmission line to supply predetermined power to the load. Further, a high-speed phase shift regulator (UPFC: Unified Power Flow Controller) includes a converter and an inverter, and controls the phase and magnitude of the applied voltage of a series transformer inserted in series in the transmission line to control power flow. Since these power flow control devices are used as constant power flow control, it is necessary that the device loss at normal time be small. In addition, it is necessary for the power command center, ISO, power consignment company, power generation company, etc. to grasp the transmission loss of these devices from the necessity of transmission power setting and fee payment.
[0005]
The power flow control device, such as an asynchronous interconnection system, a DC power transmission system, or a UPFC, to which power electronics technology is applied, includes a converter that converts alternating current to direct current and an inverter that converts direct current to alternating current. Is mainly generated by an AC / DC converter or a conversion transformer connected to an AC system.
[0006]
Conventionally, this power loss is obtained by calculation from the resistance of each device and the flowing current, or both the power at the input end and the power at the output end are detected and the difference is obtained.
[0007]
[Problems to be solved by the invention]
In the method of obtaining the power loss by calculation from the resistance of each device and the flowing current, the power loss due to the harmonics generated from the AC / DC converter of the power flow control device cannot be obtained. Further, in the method of detecting the input power and output power of the prior art and calculating the loss from the difference, a power detector having the same accuracy is required at both the input end and the output end, and the detection data of the power detector is used. Must be sent to the other end.
[0008]
An object of the present invention is to provide a loss measurement method for detecting power loss of a power flow control device by measuring power at one end of an input end or output end.
[0009]
Another object of the present invention is to use the power control information, ISO, power contractor, IPP, distributed power source, and the like to detect the detected power loss information of the power flow control device via a general-purpose communication device such as the Internet or an intranet in a company. This is the provision of a method for evaluating and determining power control and cost by delivering to a supplier company or the like.
[0010]
[Means for Solving the Problems]
The loss measurement method of the tidal current measuring device according to the present invention is such that an asynchronous interconnection device, a DC power transmission system or a UPFC converter (forward converter) side performs constant DC voltage control, and the counterpart inverter (inverse converter) side performs constant power control. In order to keep the DC voltage constant, the forward converter operates to take in power that is larger than the power set by the reverse converter by the total system loss, so the input power of the forward converter The total power loss of the system including the harmonic loss is obtained by subtracting the power setting value to be transmitted to the load from the measured value.
[0011]
Also, the loss measurement method of the power flow measuring device of the present invention is such that the forward converter side performs constant power control and the reverse converter side performs constant DC voltage control, and the reverse converter is more system-total than the output of the forward converter. Since only a small amount of power can be output, the measured value of the output power is calculated on the inverse converter side that performs constant DC voltage control, and the harmonic loss is calculated by subtracting the measured value of the output power from the power setting value transmitted to the load. Find the total power loss of the system including
[0012]
The power loss information measured as described above is sent to a power control station, power generation company, consignment company, ISO, etc. via the Internet, and power dealing including loss of the power flow control device, operation, cost evaluation, etc. are performed.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, details of the present invention will be described with reference to the drawings.
[0014]
Example 1
An asynchronous interconnection system or a DC power transmission system to which this embodiment is applied will be described. FIG. 1 shows a DC power transmission system according to this embodiment. In the present embodiment, the case where the tidal current flows from the left to the right in FIG. 1 will be described. In FIG. 1, reference numerals 14 and 24 are AC systems, 13 and 23 are AC buses, 3 is an AC interconnection line that connects two AC systems, and 1 is a self-extinguishing element such as an IGBT. A forward converter (converter) of a self-excited converter that converts to DC, 2 is a reverse converter (inverter) of a self-excited converter that converts DC to AC, 11 and 21 are DC capacitors for smoothing DC voltage, 12 , 22 are conversion transformers, and 30a, 30b are DC transmission lines. Reference numeral 100 is a tidal current command station that commands tidal power of the tidal current control apparatus, 200 is a control apparatus that controls the forward converter 1, and 300 is a control apparatus that controls the reverse converter 2. Reference numeral 201 denotes an AC current transformer that detects a current flowing through the forward converter 1, 202 denotes an AC voltage transformer, and 203 denotes a power transformer that detects input power of the forward converter 1. Reference numeral 400 denotes an all power command station (control station) that controls the power flow of the entire system, 500 denotes an ISO, a power contractor, etc., and 600 denotes a communication network such as a general-purpose Internet or an intranet.
[0015]
The asynchronous interconnection system is the same as the DC power transmission system shown in FIG. 1 except that the DC power transmission lines 30a and 30b are not provided.
[0016]
First, it will be described that the power flow between the AC systems 14 and 24 can be arbitrarily controlled with the configuration of FIG. The power flow between the AC systems 14 and 24 is performed by adjusting the voltage phase difference between the AC systems 14 and 24. When the phase of the AC system 14 is advanced by θ with respect to the AC system 24, the following equation is obtained.
[0017]
P = V1, V2, sin (θ) / X
Here, V1 is the voltage of the AC system 14, V2 is the voltage of the AC system 24, X is the impedance of the transmission line connecting the AC systems 14 and 24, and P is power.
[0018]
However, when there is a DC interconnection device, it is possible to flow power in an arbitrary direction and at a high speed according to the power setting value of the DC interconnection device regardless of the phase difference between the AC systems 14 and 24. However, since the phase difference of the AC system changes when the tidal current flows through the tidal interconnection device, the tidal current can be adjusted transiently by the tidal current control device, but the tidal current must be adjusted regularly unless the phase difference between the AC systems is adjusted. Will not change.
[0019]
Next, it will be described with reference to FIG. 2 that the loss of the power flow control device in this embodiment can be obtained by measuring only the input power on the forward converter 1 side. FIG. 2 shows the relationship between the active power and DC voltage characteristics of the forward converter and the reverse converter of the DC interconnection apparatus. The forward converter and reverse converter have constant power control characteristics and constant DC voltage control characteristics, set the forward converter power setting value to a value that fills the converter capacity, and set the DC voltage setting value to the specified value. Set to Vdref. The DC voltage setting value of the reverse converter is set to a value with a margin more than the setting value of the forward converter, for example, about 10% lower than the rating, and the power setting value is set to a value Pdref required by the load.
[0020]
The operating point when set in this way is the intersection of the forward converter characteristic and the inverse converter characteristic of FIG. When the above characteristics are provided, the input power of the forward converter becomes larger than the amount of power set in the reverse converter in order to make the DC voltage constant by the loss of the power flow control device. In other words, when the power of the forward converter is smaller than this value, the DC voltage is lower than the specified value, and conversely, when the power is larger, the DC voltage becomes higher and becomes equal to the specified voltage.
[0021]
Therefore, only the input power of the converter that controls the DC voltage can be measured to determine the total loss including the harmonic loss of the power flow control device. That is, as shown in FIG. 3, the total loss is obtained by subtracting the power setting value of the load from the input power. The reason why the absolute value of the difference between the measured power value and the load power command value is calculated in FIG. 3 is that the loss occurs in the measured power value as described above depending on the power flow direction of the power flow control device. This is because there is a case where it comes out with minus.
[0022]
By sending the power loss information obtained above to all power command centers, power contractors, ISO, etc. via general-purpose communication devices such as the Internet and intranet, it is possible to balance the power flow of all systems and reduce power loss. It is possible to calculate power transmission and transmission cost to the load in consideration.
[0023]
FIG. 4 shows the setting of the power command value that specifically considers the loss. The power command value may be a power command value obtained by adding the loss of the power flow control device to the power required for the load system as the power command value of the power flow control device, or may be a set value of the generated power on the power transmission side. All power command centers are required to have this function.
[0024]
On the other hand, regarding the cost, since the amount of loss of the tidal control device under tidal conditions is obtained, either the amount of lost power is added to the power generation cost, the power transmission cost, or the power receiving side cost. If it is decided to do so, it can be decided based on the unit price of electricity. Cost evaluation considering loss can be calculated by a power consignor, ISO, power plant, etc. using a dedicated program.
[0025]
FIG. 5 shows a general control block of the self-excited converter that realizes the control characteristics of the forward converter and the inverse converter shown in FIG. Reference numeral 211 is a constant active power control circuit, 212 is a DC voltage constant control circuit, 213 is a signal translation circuit, and outputs of the constant active power control circuit and the constant DC voltage control circuit so as to have the converter characteristics shown in FIG. The signal is selected, and this signal controls the phase of the AC output voltage for setting the effective power of the AC output of the self-excited converter, the DC output or the input DC voltage to a specified value (set value). Reference numeral 214 is a constant reactive power control circuit which controls the reactive power flowing through the system by controlling the magnitude of the output voltage of the self-excited converter. Reference numeral 215 represents a converter control unit for non-interference control of active power and reactive power. A commonly used configuration control block is shown in FIG.
[0026]
In FIG. 6, reference numeral 215a receives a command value for controlling the active power or DC voltage of the active power control circuit or DC voltage control circuit at the upper level to a specified value, and the actual current extracted from the AC current by dq conversion is An actual current (d-axis current) control circuit for controlling to this command value, 215b receives a command value for controlling the reactive power of the higher-level reactive power control circuit to a specified value, and is extracted from the AC current by dq conversion. The imaginary current (q-axis current) control circuit for controlling the imaginary current to this command value, IX represents the multiplication of the impedance of the transformer for conversion, canceling the interference due to the impedance drop of the real current or imaginary current Thus, non-interference control between the real current and the imaginary current is realized. Here, the dq conversion is performed using the function values of the sine and cosine of the phase difference β between the system voltage and the converter output voltage. Reference numeral 215e denotes a two-axis inverse conversion circuit for converting the dq axis component into a fixed αβ coordinate system, and 215f converts the αβ coordinate system to the AC voltage reference values Va21, Vb21, and Vc21 of the original three-phase rotating coordinate system. A phase conversion circuit 215g is a PWM pulse generation circuit that creates a PWM pulse of a self-excited converter from a triangular wave serving as a pulse carrier and this AC voltage reference value. With this circuit configuration, the actual current (active power) and the imaginary current (reactive power) can be controlled independently and without interference.
[0027]
(Example 2)
In the first embodiment, the case where the tidal current flows from the left to the right in the figure has been described. In this embodiment, the power flow direction is changed to the reverse of that of the first embodiment, the forward converter becomes an inverse converter, and the inverse converter becomes a forward converter, and constant power control is performed on the forward converter side. The constant DC voltage control is performed on the inverse converter side. In this case, the output of the inverse converter can output only an output smaller than the output of the forward converter by the total system loss. This is because the DC voltage drops when more power is output than the output that is less than the loss, and the DC voltage increases when less power is output than the output that is less than the loss, so the DC voltage is just the power minus the loss. The operation becomes a specified value. Therefore, if the output power is measured on the inverse converter side that performs constant DC voltage control, the total loss of the system including the harmonic loss can be obtained by subtracting this measured value from the power setting value of the forward converter.
[0028]
In the same way as above, the obtained power loss information is sent to all power control stations, power generation companies, consignment companies, ISO, etc. via the Internet and intranet, and power handling including loss of power flow control equipment, operation, cost determination and evaluation Etc.
[0029]
(Example 3)
FIG. 7 shows this embodiment. Although FIG. 1 shows a power flow control device using a self-excited converter, this embodiment is a power flow control device using an asynchronous interconnection system or a DC power transmission system using a separately excited converter. It is the same as that of FIG. 1 that the power flow between the two AC systems can be controlled by the configuration of FIG.
[0030]
In FIG. 7, the case where the direction of the tidal current flows from the left to the right in the figure will be described. In FIG. 7, reference numeral 3 denotes a forward converter (converter) of a separately-excited converter composed of elements that can control only the on-time of a thyristor or the like, 4 denotes an inverse converter (inverter) of the separately-excited converter, 31, 32. Is a DC reactor that smoothes the DC current, 301 is an AC current transformer that detects the current flowing through the inverter 1, 302 is an AC voltage transformer, and 303 is a power transformer that detects the output power of the inverter 2. .
[0031]
In this embodiment, the active power is controlled by the forward converter, and the DC voltage is controlled to be constant by the inverse converter. FIG. 8 shows the relationship between the DC current and DC voltage of the forward converter and the inverse converter at this time. The forward converter is given a direct current setting value Idref for transmitting active power necessary for the load, and has a constant direct current control characteristic. On the other hand, the inverse converter has a constant DC voltage control characteristic for keeping the DC voltage at a specified value Vdref, and a value smaller by a current margin ΔId than the current setting value Idref of the forward converter as a backup operation when the AC voltage drops. Has a constant DC current control characteristic with a current set value.
[0032]
The operating point when such a characteristic is given to the forward converter and the inverse converter is an intersection of the two characteristics. The forward converter operates to keep the active power required for the load constant, but the inverse converter performs constant DC voltage control. Will be measured. If more power is measured with the inverse converter, the DC voltage will drop below the specified value, and if less power is measured, the DC voltage will increase. Therefore, when the DC voltage is maintained at the specified value, the output power measured on the inverse converter side is smaller than the power setting value on the forward converter side by a loss. When trying to extract predetermined active power with an inverse converter, the power setting value (DC current setting value × DC voltage) of the forward converter needs to be set to a power setting value that is larger by the total system loss.
[0033]
By measuring only the output power of the inverter that performs constant DC voltage control and subtracting this measured value from the power setting value, the total loss of the power flow control system, including harmonic loss, is obtained. . The obtained loss information is sent to a power generation company, a consignment company, ISO, etc. using a communication device such as the Internet, and power dealing including loss of the power flow control device, operation and cost evaluation can be performed.
[0034]
Example 4
FIG. 9 shows this embodiment. FIG. 1 shows a power flow control device using a self-excited converter, and FIG. 7 shows a power flow control device using a separately excited converter. In this embodiment, the voltage of a series transformer inserted in series in a transmission line is shown. The power flow through the track is controlled by changing the phase.
[0035]
The voltage phase is produced by the forward and inverse converters of the same self-excited converter as in FIG. The same numbers as in the previous figures represent the same functions, so only different new ones will be described. Reference numeral 29 in FIG. 9 is a series transformer inserted in series with the transmission line, and the primary side of the transformer is excited by the inverse converter 2.
[0036]
It is known that the flow of effective and ineffective components can be controlled by controlling the magnitude and phase of the output voltage of the inverse converter. Also in this embodiment, the forward converter 1 controls the DC voltage to be constant, and the inverse converter 2 controls the active power to be constant. Similar to the description of FIG. 1, when the active power flowing through the forward converter is obtained from the current and voltage flowing through the forward converter, the power is measured to be larger by the system loss. Accordingly, the total power loss of the system including the harmonic loss can be obtained by subtracting the power set value.
[0037]
The obtained power loss data can be sent to a power generation company, a consignment company, ISO, etc. using a communication device such as the Internet, and power dealing including loss of the power flow control device, operation and cost evaluation can be performed.
[0038]
【The invention's effect】
By measuring only the active power flowing through the converter that performs constant DC voltage control, the total system loss including the harmonic loss of the power flow controller can be obtained. In addition, this loss is sent to power generation companies, power control stations, power consignment companies, ISOs, etc. via general-purpose, low-cost communication devices such as the Internet and Intranet, and power handling, operation and costs including loss of power flow control devices Can be evaluated.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a loss measurement method and a utilization method of a power flow control device according to a first embodiment.
FIG. 2 is a diagram illustrating the characteristics of active power and DC voltage of the self-excited converter according to the first embodiment.
FIG. 3 is an explanatory diagram of a loss measurement method according to the first embodiment.
FIG. 4 is an explanatory diagram of a method for creating a power command value according to the first embodiment.
FIG. 5 is a block diagram of a control unit of the self-excited converter according to the first embodiment.
6 is a block diagram of a converter control unit of the self-excited converter according to Embodiment 1. FIG.
FIG. 7 is an explanatory diagram of a loss measurement method and a utilization method of the power flow control device according to the third embodiment.
FIG. 8 is a diagram showing characteristics of a direct current and a direct current voltage of a separately excited converter according to a third embodiment.
FIG. 9 is an explanatory diagram of a loss measurement method and a utilization method of the power flow control device according to the fourth embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Forward converter (converter) of self-excited converter, 2 ... Inverter (inverter) of self-excited converter, 3 ... AC interconnection line, 11, 21 ... DC capacitor, 12, 22 ... Transformer for conversion , 13, 23 ... AC bus, 14, 24 ... AC system, 29 ... Series transformer, 30a, 30b ... DC transmission line, 100 ... Power flow command station, 200 ... Control device 1, 201, 301 ... AC current transformer, 202, 302 ... AC voltage transformer, 203 ... Power transformer, 211 ... Active power constant control circuit, 212 ... DC voltage constant control circuit, 213 ... Signal selection circuit, 214 ... Reactive power constant control circuit, 215 ... Converter control 215a ... real current (d-axis current) control circuit, 215b ... imaginary current (q-axis current) control circuit, 215e ... 2-axis reverse conversion circuit, 215f ... 3-phase conversion circuit, 215g ... PWM pulse generation circuit, 300 Controller 2,303 ... power transformer, 400 ... total power control center, 500 ... ISO, power wheeling skilled in the art, 600 ... communication network.

Claims

In a loss measurement method for a power flow control device having a forward converter for converting alternating current to direct current and an inverse converter for converting direct current to alternating current,
The power flow control device includes a converter that controls the DC voltage to be constant, and the measured value of the active power of the converter is subtracted from the power setting value of the load to include the harmonic loss. A method for measuring a loss of a power flow control device, characterized by obtaining total power loss.

In a loss measurement method for a power flow control device having a forward converter for converting alternating current to direct current and an inverse converter for converting direct current to alternating current,
From the measurement of the active power of the forward converter for setting the DC voltage of the power flow control device, the active power setting value of the power flow control device is subtracted from the measurement of the effective power of the power flow control device. A method for measuring a loss of a power flow control device, characterized by obtaining a power loss.

In a loss measurement method for a power flow control device having a forward converter for converting alternating current to direct current and an inverse converter for converting direct current to alternating current,
The active power measurement value of the reverse converter for setting the DC voltage of the power flow control device is subtracted from the active power setting value of the power flow control device, and all the power flow control device including harmonic components of the power flow control device is subtracted. A method for measuring a loss of a power flow control device, characterized by obtaining a power loss.

A method of using power loss information of a power flow control device having a forward converter that converts alternating current to direct current and an inverse converter that converts direct current to alternating current,
The power loss information is obtained by subtracting the measured value of the active power of the converter for which the power flow control device controls the DC voltage constant from the power setting value of the load, and includes the total power loss of the power flow control device including the harmonic loss. Information
The power of the power flow control device is characterized in that the power loss information is distributed to a power control station, ISO, etc. using communication means such as the Internet or an intranet, and the power flow is controlled using a signal distributed in the power control station. How to use loss information.

A method of using power loss information of a power flow control device having a forward converter that converts alternating current to direct current and an inverse converter that converts direct current to alternating current,
The power loss information is obtained by subtracting the measured value of the active power of the converter for which the power flow control device controls the DC voltage constant from the power setting value of the load, and includes the total power loss of the power flow control device including the harmonic loss. Information
A power flow control device characterized in that the power loss information is distributed to an ISO, a power contractor or a power generator using a communication means such as the Internet or an intranet, and the cost is determined or evaluated using the distributed information. How to use power loss information.