JP4119077B2 - Frequency stabilizer for power system - Google Patents

Description

【００５５】
ここで、電気出力Ｐ_e＝負荷の消費電力Ｐ_Lとみなせるので、（Ｐ_m−Ｐ_e）＝ローカル系統内の需給アンバランス量ΔＰと言える。従って、需給アンバランス量ΔＰは（１．１）式で求めることができる。
【００５６】
なお、周波数低下あるいは上昇は、系統内の電力の消費量と発電量のアンバランス、つまり、需給アンバランスによって発生するので、（１．１）式で求めた需給アンバランス量ΔＰと等量の制御を実施すれば、ローカル系統１０３内の需給アンバランスが解消され、周波数低下あるいは上昇をおさえて、且つ、周波数低下あるいは上昇が発生する前の定常時の周波数に制御（安定化）することができる。
【００５７】
前記の通り（１．１）式に用いる電気量は全てＰＵ値で、（１．１）式において推定される需給アンバランス量ΔＰは、等価発電機モデルの機械入力Ｐ_mを１．０〔ＰＵ〕としたときのＰ_mとＰ_eの差である。例えば、周波数低下側をプラスとして周波数変化率ｄｆ／ｄｔが０．０１、等価発電機モデルの慣性定数Ｍが５．０〔秒〕であった場合の需給アンバランス量ΔＰは（１．１）式から０．０１×５．０＝０．０５〔ＰＵ〕で、機械入力Ｐ_m＝１．０〔ＰＵ〕の５％が等価系統モデル内の需給アンバランス量ΔＰとなる。
【００５８】
よって、需給アンバランス量ΔＰの０．０５〔ＰＵ〕にローカル系統内の全発電機の定常時の発電量の合計値（総発電量）を掛けた値が、ローカル系統内の実際の需給アンバランス量ΔＰであり、この結果、ローカル系統内の発電機の総発電量の５％の負荷を遮断すれば、需給アンバランスが解消され周波数低下を防止できる。
【００５９】
なお、推定した需給アンバランス量ΔＰから各周波数安定化装置毎の安定化制御量（負荷制限量あるいは電源制限量）を次のように決定する。
【００６０】
監視対象とする電気所毎に設置した周波数安定化装置毎に需給アンバランス量ΔＰを推定して、この推定した需給アンバランス量ΔＰと各電気所において計測し系統状態記憶部５に保管しておいた定常時の有効電力Ｐを呼び出して定常時の有効電力Ｐを基準に、推定したΔＰの割合分を制御量Ｐ_CUT（負荷制限量あるいは電源制限量）として決定する。
【００６１】
例えば、周波数低下側を例にとって説明すると、推定した需給アンバランス量ΔＰが０．０５〔ＰＵ〕で、電気所に接続する全負荷の定常時の有効電力Ｐ_LTが２．０〔ＰＵ〕であった場合には、２．０〔ＰＵ〕の５％、つまり、０．１〔ＰＵ〕を負荷制限量とする。
【００６２】
このようにして求められた制御量Ｐ_CUTを制御部４へ渡されると、制御部４では、制御量演算部３で求めた制御量Ｐ_CUT（負荷制限量あるいは電源制限量）に応じて、監視対象の電気所に接続する負荷あるいは発電機を系統より解列し、周波数低下あるいは上昇を防止する。
【００６３】
このように本発明の第１の実施の形態によれば、監視対象の電気所端のみで、しかも、計測あるいは収集可能な情報のみで、監視対象の電気所が属する全体の系統内の需給アンバランス量を推定し、推定した需給アンバランス量に基づいて制御量を算出できるので、電力系統の各所において計測した情報を収集する必要がなく広域の情報伝送網も必要ないので、システム規模を小さくでき、また、監視対象の電気所毎に個別に監視，制御が実施できるので、装置構成が簡素で運用性の高い電力系統の周波数安定化装置を提供できる。
【００６４】
次に、本発明の第２の実施の形態の電力系統の周波数安定化装置の各構成部及び手段の作用を図１と図２と図４と図５を参照しながら説明する。
【００６５】
図１は、本発明に係わる電力系統の周波数安定化装置の構成図、図２は、図１の具体例を示す電力系統の周波数安定化装置の構成図、図５は、本発明の第２の実施の形態を示す電力系統の周波数安定化装置の構成図である。
【００６６】
図５において、系統状態計測部１は、監視対象の電気所端の電流，電圧，負荷フィーダーあるいは発電機の有効電力，系統の周波数などを含む各種電気量を時々刻々と計測する。周波数演算部２は、前記の周波数などを含む各種電気量を用いて、周波数変化率などの各種電気量の変化分を所定の演算により算出する周波数演算手段２１からなる。
【００６７】
制御量演算部３は、初期制御演算手段３１’と補正制御演算手段３２とからなる。初期制御演算手段３１’は、前記の算出した周波数変化率と監視対象の電気所が属するローカル系統内の発電機の慣性定数を用いて、第１の実施の形態に記載の手法により、監視対象の電気所が属するローカル系統の需給アンバランス量を所定の演算により推定し、推定した需給アンバランス量に応じて初期の負荷制限量あるいは電源制限量を算出する。補正制御演算手段３２は、初期、または、追加の負荷制限あるいは電源制限を実施した前と後のそれぞれの周波数変化率と、負荷フィーダあるいは発電機の有効電力から算出した係数と、制御した負荷制限量あるいは電源制限量を用いて、初期、または、追加の負荷制限あるいは電源制限を実施した後の監視対象の電気所が属するローカル系統の需給アンバランス量を所定の演算により推定し、前記の推定した需給アンバランス量に応じて追加の負荷制限量あるいは電源制限量を決定する。制御部４は、前記の負荷制限量あるいは電源制限量に応じて、負荷あるいは発電機を遮断する。
【００６８】
本発明の第２の実施の形態は、予め設定した条件に応じて、需給アンバランス量の推定と追加の負荷制限あるいは電源制限を複数回実施する点に特徴を有している。
【００６９】
次に、本発明の第２の実施の形態の処理の流れを図２と図５を用いて説明する。なお、系統状態計測部１及び周波数演算部２及び系統状態記憶部５の作用は、第１の実施の形態と同様であるので説明を省略する。
【００７０】
まず、制御量演算部３では、初期制御演算手段３１’において、周波数演算部２で算出した周波数変化率ｄｆ／ｄｔと監視対象の電気所が属するローカル系統内の発電機の慣性定数Ｍを用いて、第１の実施の形態に記載の手法により、監視対象の電気所が属するローカル系統の需給アンバランス量ΔＰ_C1を所定の演算により推定し、推定した需給アンバランス量ΔＰ_C1に応じて初期の負荷制限量あるいは電源制限量を決定する。
【００７１】
次に、補正制御演算手段３２において、初期あるいは追加の負荷制限あるいは電源制限を実施した前と後のそれぞれの周波数変化率ｄｆ／ｄｔと制御した負荷制限量あるいは電源制限量を用いて、初期あるいは追加の負荷制限あるいは電源制限を実施した後の監視対象の電気所が属するローカル系統の需給アンバランス量ΔＰ_C2を所定の演算により推定し、前記の推定した需給アンバランス量ΔＰ_C2に応じて追加の負荷制限量あるいは電源制限量を決定する。
【００７２】
以下に、初期制御演算手段３１’と、補正制御演算手段３２を詳細に説明する。
【００７３】
まず、初期制御演算手段３１’では、事故発生直後に各電気所で一律同じ割合の初期制御量Ｐ_CUT1を制御して、周波数低下速度あるいは上昇速度を抑制して、補正制御演算を実行するための時間的余裕を確保する。このため、初期制御量Ｐ_CUT1は、予め設定した固定値としても良いが、需給アンバランスによっては過制御となる可能性が考えられるので、次のように初期制御量Ｐ_CUT1を算出する。
【００７４】
周波数演算部２で算出した周波数変化率ｄｆ／ｄｔと監視対象の電気所が属するローカル系統内の発電機の慣性定数Ｍを用いて、監視対象の電気所が属するローカル系統の需給アンバランス量ΔＰ_C1を所定の演算により推定し、前記の推定した需給アンバランス量ΔＰ_C1に応じて負荷制限量あるいは電源制限量を決定する。
【００７５】
ΔＰ_C1＝Δｆ・Ｍ ・・・・（２．１）
【００７６】
具体的には、監視対象の電気所が属するローカル系統を、図４に示すように一負荷一発電機の等価系統モデルとして考えて、周波数演算部２において算出した周波数変化率ｄｆ／ｄｔと等価発電機の慣性定数Ｍを用いて、各電気所に設置した周波数安定化装置毎に、おのおの独立に（２．１）式からローカル系統内の需給アンバランス量ΔＰ_C1［％］を推定する。各電気所端で計測した周波数は、ローカル系統内でほぼ同じ様相で変動するので、各装置で算出したΔＰ_C1［％］はほぼ同量となる。
【００７７】
なお、初期制御は、補正制御演算を実行するための時間的余裕を確保するのが目的であること、慣性定数Ｍは発電機の運転状態により変化することから、Ｍは真値より小さ目の値に設定しておくことが望ましい。例えば、ローカル系統を一負荷一発電機の等価モデルに縮約したときの等価発電機の慣性定数Ｍの真値（Ｍを定格出力で加重平均した値）が１０［秒］であるとしたら、５あるいは６［秒］といったように小さ目に設定する。
【００７８】
次に、各電気所端で制御すべき初期制御量（負荷制限量あるいは電源制限量）Ｐ_CUT1は、推定した需給アンバランス量ΔＰ_C1と事故発生前の定常時の電気所内の総負荷量あるいは総発電量（＝Ｐ_LOT）を用いて（２．２）式から算出する。
【００７９】
Ｐ_CUT1＝Ｐ_LOT・ΔＰ_C1 ・・・・（２．２）
【００８０】
ここで、Δｆは、周波数演算部２で求めた周波数変化率ｄｆ／ｄｔ，Ｍは等価発電機の慣性定数で、ローカル系統を一負荷一発電機の等価系統モデルに等価縮約したときの定数を、事前に求めて設定した値であり、ローカル系統内の各発電機の定格出力で加重平均した値である。Ｐ_LOTは、事故発生前の定常時に計測した電気所内の総負荷量あるいは総発電量である。
【００８１】
なお、（２．１）式は、発電機の運動方程式から以下の通り導くことができる。監視対象の電気所が属するローカル系統を一負荷一発電機の等価系統モデルとして考え、発電機の機械入力をＰｍ，電気出力をＰｅ（＝負荷の消費電力Ｐ_L），等価発電機の慣性定数をＭとすると、発電機の運動方程式より（１．２）式が成り立つ。
【００８２】
（１．２）式について、周波数変化率ｄｆ／ｄｔ＝Δｆ，初期制御前の需給アンバランス量（Ｐｍ−Ｐｅ）＝ΔＰ₁とすると、ΔＰ_C1［％］は（２．１）式で求めることができる。
【００８３】
（２．１）式で推定される需給アンバランス量ΔＰ_C1は、例えば、周波数低下側を例にとって説明すると、等価発電機モデルの電気出力Ｐｅ（＝負荷の消費電力ＰＬ）を１．０としたときの供給量（発電量）の不足分であり、仮に、周波数低下側を正として周波数変化率ｄｆ／ｄｔ（ｄｔ＝１０ｍｓ）が０．０１、等価発電機モデルの慣性定数Ｍが５．０であった場合の需給アンバランス量ΔＰ_C1は（２．１）式から０．０１×５．０＝０．０５で、ローカル系統内の総負荷量に対して総発電量が５［％］不足していることになる。よって、ローカル系統内の総負荷量の５［％］の負荷を遮断すれば、需給アンバランスが解消され周波数低下を抑制できる。
【００８４】
次に、推定した需給アンバランス量ΔＰ_C1から各電気所端（各周波数安定化装置毎）の初期制御量Ｐ_CUT1（負荷制限量あるいは電源制限量）を求めるには、具体的には、例えば、周波数低下側を例にとって説明すると、ローカル系統内の電気所Ａ１，Ａ２，Ａ３に、Ｐ_L1＝２０００［ＭＷ］，Ｐ_L2＝１０００［ＭＷ］，Ｐ_L3＝５００［ＭＷ］の負荷（定常時の総負荷量Ｐ_LOT）があるとした場合で、各電気所端で推定した需給アンバランス量ΔＰ_C1が５［％］と推定されたときには、それぞれの電気所における制御量は、電気所Ａ１は、２０００［ＭＷ］の５［％］、つまり、１００［ＭＷ］を、電気所Ａ２は、１０００［ＭＷ］の５［％］、つまり、５０［ＭＷ］を、電気所Ａ３は、５００［ＭＷ］の５［％］、つまり、２５［ＭＷ］をその電気所で制御する初期制限量とする。分離系統内の周波数は、ほぼ同じ様相で変動し、各電気所端で推定したΔＰＣ１は、ほぼ同量となるので、分散型のシステム構成でも各電気所端において一律α［％］の初期制御を実施できる。このようにして求めた制御量を制御部４へ渡すと共に、系統状態記憶部５において保管する。
【００８５】
制御部４では、制御量演算部３で求めた初期制御量Ｐ_CUT1（初期の負荷制限量あるいは電源制限量）に応じて、監視対象の電気所に接続する負荷あるいは発電機を系統より解列し、周波数低下あるいは上昇を防止する。
【００８６】
初期制御実施後は、補正制御演算手段３２において、初期制御実施後の周波数が初期制御実施前と同じく継続して低下あるいは上昇しているか確認して、制御実施前と同じく低下あるいは上昇が継続している場合に、初期制御（初期の負荷制限あるいは電源制限）を実施した前の周波数変化率ｄｆ／ｄｔ（以下、Δｆ_bfと示す）と実施した後の周波数変化率ｄｆ／ｄｔ（以下、Δｆ_afと示す）と初期制御量Ｐ_CUT1及び負荷フィーダーあるいは発電機の有効電力から算出した負荷の増減特性係数ａ_bf及びａ_afを用いて、（２．３）式から、負荷の電圧特性や周波数特性を考慮した初期制御実施後のローカル系統内の需給アンバランス量ΔＰ_C2（＝初期制御における不足分）を推定する。なお、負荷の増減特性を考慮しない場合には、係数ａ_bf及び係数ａ_afを１．０とすればよい、また、初期制御実施前の周波数変化率Δｆ_bfと初期制御前の需給アンバランスΔＰ_C1は、系統状態記憶部５において保管しておいたものを呼び出して用いる。
【００８７】
【数２】

【００８８】
ここで、Δｆは、周波数演算部２で求めた周波数変化率ｄｆ／ｄｔであり、式の添字のｂｆは制御実施前の値、ａｆは制御実施後の値であることを示す。ΔＰ_C1は、一回目の追加制御演算では、初期制御実施前の需給アンバランス量ΔＰ_C1であり、二回目以降の追加制御演算では、初期制御量（＝ΔＰ_C1）と追加制御量（＝ΔＰ_C2）の合計値である。
【００８９】
各電気所自端で制御すべき追加制御量（追加の負荷制限量あるいは電源制限量）Ｐ_CUT2は、需給アンバランス量ΔＰ_C2［％］と事故発生前の定常時の電気所内の総負荷量あるいは総発電量（＝Ｐ_LOT）を用いて（２．４）式で算出する。
【００９０】
Ｐ_CUT2＝Ｐ_LOT・ΔＰ_C2 ・・・・（２．４）
【００９１】
推定した需給アンバランス量ΔＰ_C2から各電気所端（各周波数安定化装置毎）の追加制御量Ｐ_CUT2を求めるには、具体的には、例えば、周波数低下側を例にとって説明すると、ローカル系統内の電気所Ａ１，Ａ２，Ａ３にＰ_L1＝２０００［ＭＷ］，Ｐ_L2＝１０００［ＭＷ］，Ｐ_L3＝５００［ＭＷ］の負荷（定常時の総負荷量Ｐ_LOT）があるとした場合、各電気所端で推定した需給アンバランス量ΔＰ_C2が２［％］と推定された場合には、それぞれの電気所における追加制限量は、電気所Ａ１は、２０００［ＭＷ］の２［％］、つまり、４０［ＭＷ］を、電気所Ａ２は、１０００［ＭＷ］の２［％］、つまり、２０［ＭＷ］を、電気所Ａ３は、５００［ＭＷ］の２［％］、つまり、１０［ＭＷ］をその電気所で制御する追加負荷制限量とする。このようにして求めた追加制御量を制御部４へ渡すと共に、系統状態記憶部５において保管する。
【００９２】
制御部４では、制御量演算部３で求めた追加制御量Ｐ_CUT2（追加の負荷制限量あるいは電源制限量）に応じて、監視対象の電気所に接続する負荷あるいは発電機を系統より解列し、周波数低下あるいは上昇を防止する。
【００９３】
通常は、（２．３）式で求めた需給アンバランス量ΔＰ_C2と等量の制御を実施すれば、ローカル系統内の需給アンバランスが解消され、周波数低下あるいは上昇を抑えて、周波数低下あるいは上昇が発生する前の定常時の周波数に制御（安定化）できる。ところが、需要の増減や負荷特性の変化などの系統状態が変化した場合に、一度の追加制御では、不足制御となることが考えられる。
【００９４】
このために、追加制御後も引き続き周波数低下あるいは上昇を確認して、制御前と同様に低下あるいは上昇が継続している場合には、次の処理が行われる。
【００９５】
具体的には、系統状態記憶部５に保管した追加制御を実施した前の周波数変化率Δｆ_bfと追加制御実施後の周波数変化率Δｆ_afと系統状態記憶部５に保管した初期制御量および追加制御量の合計値Ｐ_C1を用いて、（２．３）式から、追加制御後の需給アンバランス量ΔＰ_C2を求めて、再度、追加制御を実施と共に、追加制御量を系統状態記憶部５において保管する。追加制御は、周波数低下あるいは上昇がおさまるまで繰り返し行う。
【００９６】
以下に、（２．３）式及び負荷の増減特性係数ａ_bf，ａ_afについて説明する。
【００９７】
初期制御演算と同じく、監視対象の電気所が属するローカル系統を図４に示すような一負荷一発電機の等価系統モデルとして考え、発電機の機械入力をＰｍ，電気出力をＰｅ，等価発電機の慣性定数をＭとすると、発電機の運動方程式より（１．２）式が成り立つ。以下、時間変化を示す量には（ｔ）で記す。
【００９８】
初期制御前の周波数変動は、制御前の時間をｔ−とすると、（１．２）式から、（２．５）式で表わすことができる。なお、Δｆは、周波数変化率ｄｆ／ｄｔである。
【００９９】
【数３】

【０１００】
しかし、実際には、系統分離により電力の供給量が減少した場合には電圧が低下し、これに伴い、系統分離直後の負荷量（＝Ｐｅ（ｔ−））は減少する。そこで、（２．５）式に負荷の増減特性を表わす係数ａ_bfを用いて、負荷の減少分を考慮した推定式を導くと（２．６）式となる。
【０１０１】
【数４】

【０１０２】
一方、初期制御後の周波数変動は、初期制御で各電気所で負荷あるいは発電機を一律α［％］（＝ΔＰ_C1）遮断している。したがって、ローカル系統の総負荷量あるいは総発電量に対してもα［％］の制御を実施したことになるので、制御実施後の時間をｔ＋とすると、（２．７）式で表わすことができる。なお、（２．５）式及び（２．７）式は負荷特性（負荷の電圧特性，周波数特性）が無いものと仮定した場合の近似式である。
【０１０３】
【数５】

【０１０４】
しかし、実際には、初期制御後は、負荷制限などの安定化制御による電圧上昇に伴い、第一段制御後の負荷量（＝Ｐｅ（ｔ＋）−ΔＰ_C1）は増加している。そこで、（２．７）式に負荷の増減特性を表わす係数ａ_afを用いて、負荷の増加分を考慮した推定式を導くと（２．８）式となる。
【０１０５】
【数６】

【０１０６】
時刻ｔ−とｔ＋の時間差は短いと仮定し、Ｐｍ（ｔ−）＝Ｐｍ（ｔ＋）、Ｐｅ（ｔ−）＝Ｐｅ（ｔ＋）とすると、（２．８）式−（２．５）式より、
【０１０７】
【数７】

【０１０８】
従って、
【０１０９】
【数８】

【０１１０】
（２．１０）式を（２．８）式に代入し、消費電力Ｐ_L側を正にとり、初期制限後の需給アンバランス量△Ｐ_C2を｛−Ｐｍ（ｔ＋）＋ａ_af・（Ｐｅ（ｔ＋）−ΔＰ_C1）｝とすると、ΔＰ_C2［％］は、（２．１１）式で求めることができる。
【０１１１】
【数９】

【０１１２】
ここで、初期負荷制限後の負荷量Ｐｅ（ｔ＋）は、電気所内の定常時の総負荷量Ｐ_LOTから初期制御量Ｐ_CUT1を遮断したものであり、よって、Ｐｅ（＋）＝Ｐ_L（＋）＝（Ｐ_L0−Ｐ_CUT1）＝（１−ΔＰ_C1）といえるので、ΔＰ_C2［％］は（２．１２）式（＝（２．３）式）で求めることができることとなる。つまり、（２．３）式を用いて需給アンバランス量を推定すれば、負荷の電圧特性，周波数特性を考慮したΔＰ_C2を求めることができる。
【０１１３】
【数１０】

【０１１４】
なお、負荷の増減特性係数ａ_bf，ａ_afを考慮しない場合のΔＰ_C2の推定式は、（２．１３）式となる。
【０１１５】
【数１１】

【０１１６】
次に負荷の増減特性係数ａ_bf，ａ_afの算出方法は、監視対象の各電気所自端で計測できる電気量から算出することを考慮して、時々刻々と計測した総負荷量あるいは総発電量（＝Ｐ_L）と初期制御量Ｐ_CUT1を用いて算出する。
【０１１７】
図６は、負荷の増減特性係数ａ_bf，ａ_afの概念図で、具体的には、系統分離直後に（２．１４）式から時々刻々と負荷の増減特性係数ａ_bfを算出し、（２．１５）式からその平均値を求める。また、初期制御後に（２．１６）式から時々刻々と負荷の増減特性係数ａ_afを算出し、（２．１７）式からその平均値を求める。求めたａ_bf，ａ_afを需給アンバランスの推定演算（２．３）式に用いる。例えば、電圧動揺の周期に合せて、動揺周期と同じ時間（区間）の平均値を負荷の増減特性係数ａ_bfあるいはａ_afとして用いる。また、計測した電圧を用いて、系統分離直後は、周波数低下あるいは上昇が発生する前に計測した定常時の電圧Ｖ₀より低下している間、負荷の増減特性係数ａ_bfを時々刻々と求めて、その区間の平均値を（２．３）式で用いる。また、初期制御後あるいは追加制御後は、定常時の電圧Ｖ₀あるいは初期制御直前の電圧Ｖ_C1bfより上昇している間、負荷の増減特性係数ａ_afを時々刻々と求めて、その区間の平均値を（２．３）式で用いる。なお、ｎは、データ数の総数である。
【０１１８】
【数１２】

【０１１９】
このように本発明の第２の実施の形態によれば、遮断済みの制御量の合計値と周波数変化率のみで、監視対象の電気所が属する系統内の需給アンバランス量を推定できるので、演算のためのパラメータ設定が必要なく、また、推定した需給アンバランス量から制御量を算出するので需要の増減などの系統状態が変化しても対応でき、系統運用者の負担を低減することができる。さらに、追加制御を繰り返し実施するので不足制御を防止でき、また、監視対象の電気所端のみで計測あるいは収集可能な情報のみで、需給アンバランス量を推定し、推定した需給アンバランス量に基づいて制御量を算出できるので、電力系統内の各所において計測した情報を収集する必要がなく広域の情報伝送網も不要で、システム規模を小さくでき、また、監視対象の電気所毎に個別に監視，制御が実施でき、装置構成が簡素で制御性が高く運用性や保守性に優れた電力系統の周波数安定化装置を提供できる。
【０１２０】
また、電気所の有効電力から求めた負荷の増減特性係数を考慮して需給アンバランス量の推定を行えるので、推定精度を高めることができる。
【０１２１】
さらに、本発明の第２の実施の形態において、負荷の増減特性係数を、電気所の有効電力に代えて、計測した電圧から求め、ローカル系統内の需給アンバランス量を推定する周波数安定化装置について説明する。
【０１２２】
図５の補正制御演算手段３２において、初期あるいは追加の負荷制限あるいは電源制限を実施した後の監視対象の電気所が属する系統の需給アンバランス量を推定する際に、初期あるいは追加の負荷制限あるいは電源制限を実施した前と後のそれぞれの周波数変化率及び計測した電圧から算出した係数と制御した負荷制限量あるいは電源制限量を用いる。
【０１２３】
具体的には、初期の負荷制限を実施した際に発生する電圧上昇による影響を除去するため、初期制御実施後のローカル系統内の需給アンバランス量ΔＰ_C2を（２．１８）式から推定する。
【０１２４】
【数１３】

【０１２５】
ここで、ａ_bfv，ａ_afvは、電圧の低下や上昇傾向を表わす電圧変動係数であり、電圧変動分を考慮した需給アンバランス量の推定式である。なお、ａ_bfv，ａ_afvは、以下のように求める。
【０１２６】
電圧変動係数ａ_bfv，ａ_afvの算出方法は、監視対象の電気所端で計測できる電気量から算出することを考慮して、各電気所の事故発生前の定常時の電圧Ｖ₀と時々刻々と計測した電圧Ｖｎと周波数偏差Δｆｎを用いて算出する。
【０１２７】
具体的には、（２．１９）式あるいは（２．２０）式から時々刻々と電圧変動係数ａ_bfvnを算出して、その平均値を（２．２１）式から求める。また、（２．２２）式あるいは（２．２３）式から時々刻々と電圧変動係数ａ_afvnを算出して、その平均値を（２．２４）式から求める。求めた電圧変動係数ａ_bfvn、ａ_afvを、需給アンバランスの推定演算の（２．３）式に用いる。
【０１２８】
例えば、電圧変動係数ａ_bfvは、系統分離後の電圧動揺の周期にあわせて、動揺周期と同じ時間（区間）の平均値を用いる。電圧変動係数ａ_afvは、初期制御を実施してから、電圧動揺の周期に合せて、動揺周期と同じ時間（区間）の平均値を用いる。または、電圧変動係数ａ_bfvは、時々刻々と計測した電圧Ｖｎが、定常時の電圧Ｖ₀より低下している間、電圧変動係数ａ_bfvnを求めて、その区間の平均値を（２．２１）式で求める。電圧変動係数ａ_afvは、定常時の電圧Ｖ₀または、初期制御直前の電圧Ｖ_C1bfより上昇している間、電圧変動係数ａ_afvnを求めて、その区間の平均値を（２．２４）式で求める。
【０１２９】
【数１４】

【０１３０】
ここで、ｎは、データ数の総数。（２．２２）式及び（２．２３）式では、Ｖ₀の代わりに、初期制御直前の電圧Ｖ_C1bfを用いても良い。Ｋ_VAは、負荷の電圧特性の割合を設定する定数である。Ｋ_VBは、予め設定した係数である。αは、予め設定した負荷の電圧特性指数である。Ｋ_fPは、予め設定した周波数特性定数［％／Ｈｚ］である。Δｆｎは、計測した周波数から求めた（基準周波数からの）周波数偏差［Ｈｚ］である。
【０１３１】
このように、本発明の第２の実施の形態において、さらに、計測した電圧から算出した電圧変動係数として、負荷の増減特性係数を求めることにより、電圧変動を考慮した需給アンバランス量の推定を行えるので、推定精度を高めることができる。また、電圧変動の影響を除去するための周波数の平滑化処理を削除あるいは平滑化処理に用いるデータ区間長の短縮を図ることができるため、追加制御量を短時間に算出できる。
【０１３２】
次に、本発明の第３の実施の形態に係わる電力系統の周波数安定化装置の各構成部及び手段の作用を図１と図２と図７を参照しながら説明する。
【０１３３】
本発明の第３の実施の形態に係わる電力系統の周波数安定化装置は、第１の実施の形態または第２の実施の形態に記載の電力系統の周波数安定化装置の周波数演算部２において、算出した周波数変化率などの各種電気量の変化分や計測した周波数などに平滑化処理（フィルタリング）を含む誤差対策を施す周波数平滑化手段２２を有した構成を特徴とするものである。
【０１３４】
次に、本発明の第３の実施の形態の全体の処理の流れを図２と図７を参照して説明する。なお、系統状態計測部１及び制御量演算部３及び制御部４及び系統状態記憶部５の作用と周波数演算部２の周波数演算手段２１の作用は、第１の実施の形態あるいは第２の実施の形態と同様であるので説明を省略する。
【０１３５】
ここで、例えば、系統分離などが発生した後の分離系統の周波数の変化を見ると、系統内の発電機の動揺などの影響により、周波数が短い周期で動揺することがある。このような場合に、計測した周波数をそのまま用いて周波数変化率を求めると、算出した時点によって周波数変化率が変わり、前記の（１．１）式、（２．１）式あるいは、（２．３）式を用いてローカル系統内の需給アンバランス量ΔＰを推定しようとすると、周波数変化率の変化、つまり、周波数動揺の影響により、推定結果がばらつくことが考えられる。このため、周波数動揺の影響を排除あるいは低減する必要がある。
【０１３６】
図７に示す周波数演算部２の周波数平滑化処理手段２２は、算出した周波数変化率などの各種電気量の変化分や計測した周波数などに平滑化処理を施し、これら各種電気量が長周期あるいは短周期に動揺する場合やごく短時間の間に急激に変化する場合の影響を低減する。例えば、平滑化処理として、ある一定の区間の周波数変化率や周波数などの各種電気量の平均を求める。
【０１３７】
具体的には、平均を求める区間を、データ区間長Ｔ_SMPとして時間で設定する。系統状態記憶部５に保管しておいた、周波数低下あるいは上昇後に計測した各種電気量や算出した周波数変化率を用いて、低下あるいは上昇が発生した時点を基準にデータ区間長Ｔ_SMP間のデータを用いて、各電気量毎にこの区間の平均値を求めて、その平均値を制御量演算部３の制御量の演算に用いる。
【０１３８】
なお、各種電気量は時々刻々と計測されるので、新しいデータが計測された場合には、データ区間を更新して平均値を時系列的に継続して求める。つまり、最も古いデータを除いて、新しいデータを追加した区間の平均を求める。新しいデータが計測される度に、同様の作業を繰り返す。
【０１３９】
ここで、平滑化に用いるデータ区間長Ｔ_SMPは、例えば、電力動揺の周期と同じに設定する。動揺の周期が１〔秒〕程度ならば、１秒間の平均値を時系列的に継続して求める。以上のように平滑化処理された周波数変化率や周波数などの各種電気量を制御量演算部３へ渡すと共に、系統状態記憶部５において保管する。制御量演算部３では、平滑化処理された各種電気量を用いて制御量を算出する。
【０１４０】
このように本発明の第３の実施の形態によれば、需給アンバランス量を求める際に用いる各種電気量に平滑化処理を施しているので、周波数が長周期あるいは短周期に動揺する場合やごく短時間に急激に変化する場合でも、精度良く需給アンバランス量を推定でき、且つ、推定結果のばらつきを防止するので、高精度で高信頼度の電力系統の周波数安定化装置を提供できる。
【０１４１】
次に、本発明の第４の実施の形態に係わる電力系統の周波数安定化装置の各構成部及び手段の作用を図１と図２と図８を参照しながら説明する。
【０１４２】
本発明の第４の実施の形態の電力系統の周波数安定化装置は、第１の実施の形態または第２の実施の形態に記載の電力系統の周波数安定化装置の周波数演算部２において、計測した系統の周波数などを含む各種電気量を用いて、所定の演算により将来の周波数などの各種電気量の変化を予測する周波数変動予測手段２３を備えた構成とした点に特徴を有している。
【０１４３】
次に、全体の処理の流れを図１と図２と図８を用いて説明する。なお、系統状態計測部１及び制御量演算部３及び制御部４及び系統状態記憶部５の作用と周波数演算部２の周波数演算手段２１及び周波数平滑化手段２２の作用は、第１の実施の形態乃至第３の実施の形態と同様であるので説明を省略する。
【０１４４】
まず、図８に示す周波数演算部２の周波数変動予測手段２３では、計測した系統の周波数などの各種電気量を用いて、所定の演算により将来の周波数などの各種電気量の変化を予測する。例えば、系統状態記憶部５に保管した過去の周波数などを含む各種電気量を用いて、最小二乗法などの手法により周波数予測式を作成して、数百ミリ秒先の周波数値を予測する。
【０１４５】
周波数予測式は、次の（４．１）式に示すように１次あるいは次の（４．２）式に示すような２次式の予測関数として、過去の周波数を用いて、最小二乗法などの既存の手法により係数ａ₀〜ａ₂を求める。そして、作成した周波数予測式を用いて、数百ミリ秒先の周波数値を予測する。なお、周波数は時々刻々と変化するので、最小二乗法に用いる周波数を更新しながら、これらの一連の動作を繰り返し行って、時々刻々と将来の周波数を予測する。
【０１４６】
Δｆ（ｔ）＝ａ₀＋ａ₁ｔ ・・・・（４．１）
Δｆ（ｔ）＝ａ₀＋ａ₁ｔ＋ａ₂ｔ² ・・・・（４．２）
【０１４７】
次に、時々刻々と予測した周波数を用いて、周波数変化率ｄｆ／ｄｔを演算により算出し、演算結果を制御量演算部３へ渡すと共に、系統状態記憶部５で保管する。例えば、ｄｔ＝１０ｍｓとして周波数変化率を継続的に算出する。制御量演算部３では、予測した将来の周波数やその周波数変化率などを用いて演算を行う。
【０１４８】
このように本発明の第４の実施の形態によれば、予測した将来の周波数やその周波数変化率を用いて演算を行うので、実測値を用いて演算する場合より早い時点で演算結果を得ることができると共に、早い時点で制御を実施できるので、周波数低下あるいは上昇を短時間で安定化する電力系統の周波数安定化装置を提供できる。
【０１４９】
なお、本発明の第４の実施の形態は、図９に示すように実施できる。
【０１５０】
この図９の実施の形態は、第３の実施の形態による周波数平滑化処理手段２２を図８に追設して、周波数の動揺や短時間に急激に変化した場合でも精度よく需給アンバランス量を推定できる。
【０１５１】
次に、本発明の第５の実施乃至第８の実施の電力系統の周波数安定化装置の各構成部及び手段の作用を図１と図２と図１０と図１２を参照しながら順次説明する。
【０１５２】
本発明の第５の実施の形態の電力系統の周波数安定化装置は、図１０に示すように、図５に示す第２の実施の形態に記載の電力系統の周波数安定化装置の制御量演算部３において、予め設定した所定の条件を用いて、需給アンバランス量を推定する演算を開始する条件を切り換える制御演算開始判定手段３０を追設した構成とする点に特徴を有している。
【０１５３】
次に、本発明の第５の実施の形態の全体の処理の流れを図２と図１０と図１１を用いて説明する。なお、系統状態計測部１及び周波数演算部２及び制御部４及び系統状態記憶部５の作用は、第１の実施の形態乃至第４実施のいずれかと同様であるので説明を省略する。
【０１５４】
まず、図１０の制御量演算部３の制御演算開始判定手段３０では、計測した周波数などの各種電気量と予め設定した所定の条件を用いて、需給アンバランス量ΔＰを推定する演算を開始する条件を切り換える。例えば、計測した周波数を用いて演算を開始するかどうかの動作判定を行う場合には、判定条件として、動作判定しきい値ｆ_LMを複数設定して、計測した周波数と動作判定しきい値ｆ_LMとを比較して、周波数がしきい値ｆ_LMを超えた場合には動作条件成立と判定して、需給アンバランス量を推定する演算を開始する。
【０１５５】
なお、動作判定しきい値ｆ_LMは、系統運用の周波数制御体系などを基にして設定すれば、系統運用に見合った制御を実施できる。
【０１５６】
具体的には、周波数低下側を例にとって全体の処理の流れを説明すると、図１１及び図１２に示すように、まず、周波数演算部２において、周波数などの各種電気量の計測と周波数変化率などを算出する（Ｓ１１，Ｓ１２）。
【０１５７】
続いて、制御演算開始判定手段３０において、周波数が低下しているかどうかを判定して（Ｓ１３）、低下している場合には、計測した周波数と第一の動作判定しきい値ｆ_LM1（例えば、５９．０Ｈｚ）とを比較する（Ｓ１４）。この比較でしきい値ｆ_LM1以下の場合には、初期制御演算手段３１’を動作させ、初期の制御量を算出し制御する（Ｓ１５〜Ｓ１７）。
【０１５８】
一方、しきい値ｆ_LM1以下となっていない場合には、（Ｓ１１）から（Ｓ１４）の処理を繰り返し行う。その後、（Ｓ１６，Ｓ１７）の初期制御実施後も引き続き、（Ｓ１１）から（Ｓ１５）の処理を行い、初期制御実施後も継続して周波数が低下している場合は、図１２に示す処理へ移行する。
【０１５９】
まず、追加制御の実施回数により動作判定しきい値ｆ_LM2〜ｆ_LMnを選択し（Ｓ１８）、計測した周波数と選択したしきい値ｆ_LMを比較する（Ｓ１９）。この比較でしきい値ｆ_LM以下の場合には、補正制御演算手段３２を動作させ、追加の制御量を算出し追加制御１回目の制御をする（Ｓ２０ａ，２１ａ）。一方、しきい値ｆ_LM以下となっていない場合には、図１１の（Ｓ１１）から（Ｓ１４）及び図１２の（Ｓ１８ｍ）〜（Ｓ１９ｍ）の処理を繰り返し行う。
【０１６０】
すなわち、（Ｓ２０ａ，２１ａ）の追加制御実施後も引き続き（Ｓ１１）から（Ｓ１４）及び（Ｓ１８ｍ）〜（Ｓ２１ｍ）の処理を行って、周波数低下がなくなるまで、つまり、（Ｓ１３）において、周波数低下なしと判定されるか、追加制御の上限回数（ｍ回目）となるまで繰り返し行う。
【０１６１】
また、本実施の形態は、第３の実施の形態で説明した図７に示す周波数平滑化処理手段２２と組み合わせて用いる場合には、図１３に示す構成となる。この場合には、周波数低下側を例にとって説明すると、図１４及び図１５に示すような処理の流れとなる。
【０１６２】
まず、周波数演算部２において、周波数などの各種電気量の計測と周波数変化率などを算出する（Ｓ１１，Ｓ１２）。続いて、計測した周波数などの各種電気量や算出した周波数変化率などに周波数演算手段２１によって平滑化処理を施す（Ｓ１２ａ）。次に、制御量演算開始判定手段３０において、周波数が低下しているかどうかを判定して（Ｓ１３）、低下している場合には、平滑化処理された周波数と第一の動作判定しきい値ｆ_LM1とを比較する（Ｓ１４）。この比較でしきい値ｆ_LM1以下の場合には、初期制御演算手段３１’を動作させ、初期の制御量を算出し制御する（Ｓ１６，Ｓ１７）。
【０１６３】
一方、しきい値ｆ_LM1以下となっていない場合には、（Ｓ１１）から（Ｓ１４）の処理を繰り返し行う。その後、（Ｓ１６，Ｓ１７）の初期制御実施後も引き続き（Ｓ１１）から（Ｓ１５）の処理を行い、初期制御実施後も継続して周波数が低下している場合には、図１５に示す処理へ移行する。
【０１６４】
まず、追加制御の実施回数により動作判定しきい値ｆ_LM2〜ｆ_LMnを選択し（Ｓ１８）、計測した周波数と選択したしきい値ｆ_LMを比較する（Ｓ１９）。この比較によりしきい値ｆ_LM以下の場合には、補正制御演算手段３２を動作させ、追加の制御量を算出し追加制御１回目の制御をする（Ｓ２０ａ，２１ａ）。一方、しきい値ｆ_LM以下となっていない場合には、図１４の（Ｓ１１）から（Ｓ１５）及び図１５の（Ｓ１８ｍ）〜（Ｓ１９ｍ）の処理を繰り返し行う。
【０１６５】
すなわち、（Ｓ２０ａ，２１ａ）の追加制御実施後も引き続き（Ｓ１１）から（Ｓ１５）及び（Ｓ１８ｍ）〜（Ｓ２１ｍ）の処理を行い、周波数低下が解消するまで、つまり、（Ｓ１３）において、周波数低下なしと判定されるか、追加制御の上限回数（ｍ回目）となるまで繰り返し行う。
【０１６６】
この実施の形態によれば、第３の実施の形態で説明したように、平滑化処理として、ある一定区間の平均を求めるような場合には、平滑化処理に用いるデータを収集している間、つまり、初期制御演算では、周波数低下が発生してからデータ区間長Ｔ_SMP分時間が経過するまでの間、補正制御演算では、初期あるいは追加制御を実施してからデータ区間長Ｔ_SMP分時間が経過するまでの間に、系統の周波数が動作判定しきい値ｆ_LMを超えてしまうことが考えられる。
【０１６７】
この様な場合に、平滑化処理を重視してデータ収集を継続すると安定化制御が遅れ、系統に重大な影響を与えかねないので、これを防ぐために、常に、計測した周波数としきい値ｆ_LMとの比較を行って、周波数がしきい値ｆ_LMを超えた場合には、平滑化処理のデータ収集を中断する。そして、データ収集を始めてから周波数がしきい値ｆ_LMを超えてデータ収集が中断されるまでの間に集めたデータを用いて、この間の各種電気量毎の平均値を求め、その平均値を用いて、制御量演算部３において制御量を算出する。
【０１６８】
なお、前記に説明した制御演算開始判定手段３０では、動作判定に時々刻々と計測した周波数の実測値を用いているが、第４の実施の形態で説明した図８に示す周波数変動予測手段２３と組み合わせて実施することができる。この実施の形態によれば、予測した将来の周波数を用いて動作判定を行えるので、現時点の実測値を使って判定する場合よりも、早い時点で動作判定ができ、図１４の（Ｓ１１）〜（Ｓ１３）に代えて、図１６に示すような処理の流れとして実施できる。
【０１６９】
このように本発明の第５の実施の形態によれば、予め設定した条件を基にして、段階的に制御が実施できるので、系統運用に合わせた制御が可能で、運用性の高い装置となる。
【０１７０】
次に、本発明の第６の実施の形態について説明する。第６の実施の形態は、図１０乃至図１６に示す第５の実施の形態における需給アンバランス量を推定する演算を開始するかどうかを判定する動作判定しきい値の設定値を、各電気所に設置した周波数安定化装置毎に、各監視対象の電気所に接続される負荷フィーダあるいは発電機などの系統設備の周波数低下あるいは上昇に対する許容度に応じて設定するものである。
【０１７１】
例えば、一例として、周波数上昇に対して弱い発電機Ｇ_Aが接続されている電気所を監視・制御する周波数安定化装置Ａと、逆に、周波数上昇に対して強い発電機Ｇ_Bが接続されている電気所を監視・制御する周波数安定化装置Ｂがあった場合に、周波数安定化装置Ａのしきい値ｆ_LMiAを安定化装置Ｂのしきい値ｆ_LMiBより小さ目、つまり、基準周波数に近い値で設定し、安定化装置Ｂのしきい値ｆ_LMiBは安定化装置Ａのしきい値ｆ_LMiAより大き目、つまり、基準周波数より離れた値で設定する。ここで、添字ｉは、しきい値ｆ_LMの設定数である。
【０１７２】
このように本発明の第６の実施の形態によれば、電力系統の周波数安定化装置が電力系統の複数の電気所に設置されている場合に、複数の周波数安定化装置間で動作条件を違えることができるので、協調を取った安定化制御により必要以上の解列を防止できる。
【０１７３】
次に、本発明の第７の実施の形態について説明する。
【０１７４】
第７の実施の形態は、図１０乃至図１６に示す第５の実施の形態における制御量演算部３において、予め設定した所定の条件を用いて、初期あるいは追加の負荷制限あるいは電源制限を実施した後の需給アンバランス量を推定する演算、つまり、補正制御演算をロックするものである。
【０１７５】
具体的には、予め設定した補正制御演算ロック時間Ｔ_LKを用いて、初期あるいは追加の負荷制限実施後は、Ｔ_LKだけ需給アンバランス量を推定する演算をロックする。例えば、Ｔ_LK＝０．２〔秒〕として、初期あるいは追加の負荷制限後０．２秒間は、初期あるいは追加の負荷制限実施後の需給アンバランス量の推定、つまり、補正制御演算をロックする。
【０１７６】
ここで、周波数低下を防止する安定化制御手段として負荷制限が考えられるが、例えば、系統から解列する負荷の近傍にスタコンなどの容量性の負荷や系統設備があるような系統では、負荷制限直後にスタコンのフェランチ効果による電圧上昇が発生することが考えられる。この電圧上昇が発生している間は、負荷の電圧特性によって負荷の消費電力が増加するので、この過渡的な電圧上昇が発生している間に、需給アンバランス量を推定すると多めに（過剰に）推定され、過剰制御を行ってしまうことが考えられる。
【０１７７】
これを防止するため、負荷制限後の過渡的な電圧上昇の影響を避けるため数百ミリ秒間は、補正制御演算をロックして過剰制御を防止する。なお、第３の実施の形態のような平滑化処理手段と組合せる場合は、データ区間長との兼ね合いも考慮して、電圧上昇の影響がなくなるように補正制御演算ロック時間Ｔ_LKを設定する。
【０１７８】
このように第７の実施の形態によれば、負荷制限後の過渡的な電圧上昇が発生している間は、補正制御演算をロックするので、電圧上昇に伴って負荷の消費電力が増加し過剰に制御量が算出される場合でも、過剰制御を防止でき、信頼性の高い装置とすることができる。
【０１７９】
次に、本発明の第８の実施の形態について説明する。
【０１８０】
第８の実施の形態は、図１０乃至図１６に示す第５の実施の形態における制御量演算部３において、計測した電圧と予め設定したしきい値を用いて、初期あるいは追加の負荷制限あるいは電源制限を実施した後の需給アンバランス量を推定する演算、つまり、補正制御演算をロックするものである。
【０１８１】
具体的には、時々刻々と計測した電圧Ｖなどの各種電気量と予め設定した補正制御演算ロック判定しきい値Ｖ_LKを用いて、初期あるいは追加の負荷制限実施後の電圧Ｖがしきい値Ｖ_LK以上である間は、次の（１．１０）式の条件で補正制御演算をロックする。
【０１８２】
Ｖ≧Ｖ_LKの間、補正制御演算ロック ・・・・（１．１０）
【０１８３】
例えば、しきい値Ｖ_LKは、定常状態での運用時の電圧が１．００〔Ｐ．Ｕ．〕であるならば、１．００〜１．２０〔Ｐ．Ｕ．〕程度の範囲で設定し、例えば、Ｖ_LK＝１．０５〔Ｐ．Ｕ．〕と予め設定しておく。
【０１８４】
このように第８の実施の形態によれば、負荷制限後の過渡的な電圧上昇が発生している間は、補正制御演算をロックするので、電圧上昇に伴って負荷の消費電力が増加し過剰に制御量が算出される場合でも、過剰制御を防止でき、信頼性の高い装置とすることができる。
【０１８５】
次に、本発明の第９の実施の形態及び第１０の実施の形態の電力系統の周波数安定化装置の各構成部及び手段の作用を図１と図２と図１７と図１８を参照しながら説明する。
【０１８６】
本発明の第９の実施の形態の電力系統の周波数安定化装置は、第１の実施の形態あるいは第２の実施の形態に記載の電力系統の周波数安定化装置の制御量演算部３において、需給アンバランス量を推定する際に用いる等価発電機モデルの慣性定数Ｍを、調整する演算条件設定手段３１０を備えた点に特徴を有している。
【０１８７】
次に、全体の処理の流れを図２と図１７と図１８とを用いて説明する。なお、系統状態計測部１及び周波数演算部２及び制御部４及び系統状態記憶部５の作用は、第１の実施の形態乃至第３の実施の形態のいずれかあるいは第５の実施の形態と同様であるので説明を省略する。
【０１８８】
図１７または図１８に示す制御量演算部３の演算条件設定手段３１０では、需給アンバランス量ΔＰを推定する際に用いる前述した（１．１）式中の等価発電機モデルの慣性定数Ｍを調整する。例えば、慣性定数Ｍを予め複数設定しておき、周波数変化率ｄｆ／ｄｔの大きさにより選択して演算に用いるようにする。
【０１８９】
具体的には、次の（９．１）式の関係を予め設定しておき、周波数演算部２で求めた周波数変化率ｄｆ／ｄｔを用いて、（９．１）式との関係と比較して、条件を満足する中で最も大きいα_n（周波数変化率）に対応するＭ_nを演算に用いる慣性定数Ｍとして決定する。
【０１９０】
例えば、ｄｆ／ｄｔ≧α₁及びｄｆ／ｄｔ≧α₂の条件が成立する場合、α₁＜α₂…＜α_nの関係から、α₂に対応するＭ₂を演算に用いる。これにより、周波数変化率ｄｆ／ｄｔが大きいほど大きな慣性Ｍ_nが選択されるので、慣性定数Ｍを固定値として用いた場合より、周波数変化率ｄｆ／ｄｔが大きい、つまり、周波数が急激に、且つ、大幅に変化する場合ほど、制御量が多めに算出されるようになる。
【０１９１】
ｄｆ／ｄｔ≧α₁のときＭ₁，ｄｆ／ｄｔ≧α₂のときＭ₂，…，
ｄｆ／ｄｔ≧α_nのときＭ_n，ｄｆ／ｄｔ＜α₁のときＭ₁ ・・・・（９．１）
但し、α₁＜α₂…＜α_n、且つ、Ｍ₁＜Ｍ₂…＜Ｍ_n
【０１９２】
ここで、α_nは、周波数変化率ｄｆ／ｄｔであり予め設定しておく。Ｍ_nは、慣性定数であり予め設定しておく。それぞれｎは、設定値の総数。
【０１９３】
なお、第３の実施の形態の周波数平滑化処理手段２２と第５の実施の形態の制御演算開始判定手段３０と組み合わせて用いれば、前記のように、周波数変化率が大きい場合、つまり、周波数が急激に、且つ、大幅に低下あるいは上昇する場合に、初期の制御量が多めに制御されるので、初期制御後の周波数低下度合いが緩やかになり、補正制御の動作判定しきい値に達する（補正制御演算を開始する）までに時間的な余裕が生まれるので、平滑化処理に用いるデータ数を増やして平滑化処理の効果を高めることができ、補正制御演算において精度よく追加制御量を算出できる。
【０１９４】
このように第９の実施の形態によれば、需給アンバランス量を推定する際に用いる等価発電機モデルの慣性定数を、周波数変化率の大きさを用いて自動的に調整するので、実現象に応じた制御量を算出できる。また、第３の実施の形態の周波数平滑化処理手段と第５の実施の形態の制御演算開始判定手段と組み合わせた場合には、制御の緊急性が高い周波数変化率が大きい場合に初期の制御量が多めに制御されるので、制御後に時間的余裕が生まれるので、平滑化処理に用いるデータ数を増やして精度よく追加制御量を算出でき、運用性が高く制御量を高精度に算出する装置とすることができる。
【０１９５】
次に、本発明の第１０の実施の形態について説明する。
【０１９６】
第１０の実施の形態は、図１７または図１８の演算条件設定手段３１０において、需給アンバランス量を推定する際に用いる等価発電機モデルの慣性定数Ｍを、周波数変化率ｄｆ／ｄｔを用いて補正するものである。
【０１９７】
具体的には、演算条件設定手段３１０は、前述する（１．１）式中の慣性定数Ｍを、図１７または図１８の周波数演算部２で求めた周波数変化率ｄｆ／ｄｔを用いて、（１０．１）式及び（１０．２）式のようにして補正するものである。
【０１９８】
α＝Ｋ_ADJ・Δｆ ・・・・（１０．１）
Ｍ_RE＝α・Ｍ ・・・・（１０．２）
【０１９９】
ここで、Δｆは、周波数変化率ｄｆ／ｄｔである。Ｋ_ADJは、予め設定した係数である。Ｍは、予め設定した慣性定数であり、Ｍ_REは補正後の慣性定数である。
【０２００】
なお、第３の実施の形態の周波数平滑化処理手段２２と第５の実施の形態の制御演算開始判定手段３０と組み合わせて用いれば、前記のように、周波数変化率が大きい場合、つまり、周波数が急激に、且つ、大幅に低下あるいは上昇する場合に、初期の制御量が多めに制御されるので、初期制御後の周波数の低下度合いが緩やかになる。このため補正制御の動作判定しきい値に達する（補正制御演算を開始する）までに時間的な余裕が生まれるので、平滑化処理に用いるデータ数を増やして平滑化処理の効果を高めることができ、補正制御演算において精度よく追加制御量を算出できる。
【０２０１】
このように第１０の実施の形態によれば、需給アンバランス量を推定する際に用いる等価発電機モデルの慣性定数を、周波数変化率の大きさを用いて自動的に調整するので、実現象に応じた制御量を算出できる。さらに、第３の実施の形態の周波数平滑化処理手段と第５の実施の形態の制御演算開始判定手段と組み合わせた場合には、制御の緊急性が高い周波数変化率が大きい場合に初期の制御量が多めに制御されるので、制御後に時間的余裕が生まれ、平滑化処理に用いるデータ数を増やして精度よく追加制御量を算出でき、運用性が高く制御量を高精度に算出する装置とすることができる。
【０２０２】
次に、本発明の第１１の実施の形態の電力系統の周波数安定化装置の各構成部及び手段の作用を図１と図２と図１９または図２０を参照しながら説明する。
【０２０３】
本発明の第１１の実施の形態に係わる電力系統の周波数安定化装置は、第１の実施の形態または第２の実施の形態に記載の電力系統の周波数安定化装置の制御量演算部３において、計測した電圧などの各種電気量を用いて、算出した制御量を補正する制御量補正演算手段３３を備える構成とした点に特徴を有している。
【０２０４】
次に、全体の処理の流れを図２と図１９と図２０を参照して説明する。なお、系統状態計測部１及び周波数演算部２及び制御部４及び系統状態記憶部５の作用と、これから説明する制御量補正演算手段３３以外の制御量演算部３の手段の作用は、第１の実施の形態あるいは第２の実施の形態と同様であるので説明を省略する。
【０２０５】
図１９または図２０の制御量補正演算手段３３では、算出した制御量Ｐ_CUTを、計測した電圧などの各種電気量を用いて補正し、補正した制御量Ｐ_CMを制御部４へ渡す。
【０２０６】
具体的には、系統状態記憶部５に保管しておいた周波数低下あるいは上昇が発生する前に計測した電圧Ｖ₀と現在の電圧Ｖを用いて、算出した制御量Ｐ_CUTを（１１．１）式と（１１．２）式を用いて補正を行いあるいは（１１．１）式と（１１．３）式を用いて補正する。なお、現在の電圧値の代わりに、制御実施後から現在までに計測した電圧の平均値を用いても良い。
【０２０７】
【数１５】

【０２０８】
ここで、Ｐ_CUTは、図１９に示すように第１の実施の形態と組み合わせた場合は、制御量Ｐ_CUTであり、図２０に示すように第２の実施の形態と組み合わせた場合は、初期制御量Ｐ_CUT1あるいは追加制御量Ｐ_CUT2である。Ｋ_PAは、負荷の電圧特性の割合を設定する定数である。Ｋ_PBは、予め設定した係数である。αは、予め設定した電圧特性指数である。Ｋ_fPは、予め設定した周波数特性定数〔％／Ｈｚ〕である。Δｆは、計測した周波数から求めた（基準周波数からの）周波数偏差〔Ｈｚ〕である。
【０２０９】
なお、制御量Ｐ_CUTを補正する代わりに、推定した需給アンバランス量ΔＰを上記方法にて補正し、補正後のΔＰを用いて制御量Ｐ_CUTを算出してもよい。
【０２１０】
このように本発明の第１１の実施の形態によれば、計測した各種電気量を用いて制御量を自動的に補正するので、実現象に即した制御量を算出でき、運用性の高い装置とすることができる。
【０２１１】
次に、本発明の第１２の実施の形態の電力系統の周波数安定化装置の各構成部及び手段の作用を図２と図２１と図２２を参照しながら説明する。
【０２１２】
本発明の第１２の実施の形態の電力系統の周波数安定化装置は、第１の実施の形態または第２の実施の形態に記載の電力系統の周波数安定化装置の制御量演算部３において、予め設定した所定の条件を基に、解列する負荷フィーダーあるいは発電機を選択する制御対象決定手段３４を備えた構成とした点に特徴を有している。
【０２１３】
次に、全体の処理の流れを図２と図２１及び図２２を用いて説明する。なお、系統状態計測部１及び周波数演算部２及び系統状態記憶部５の作用とこれから説明する制御対象決定手段３４以外の制御量演算部３の手段の作用は、第１の実施の形態あるいは第２の実施の形態と同様であるので説明を省略する。
【０２１４】
図２１または図２２の制御対象決定手段３４は、各制御量演算手段において算出した制御量（Ｐ_CUTあるいはＰ_CUT1あるいはＰ_CUT2）に応じて、実際に系統から解列する負荷フィーダーあるいは発電機を選択する。例えば、系統状態計測部１において時々刻々と計測した各種電気量あるいは系統状態記憶部５において保管した定常時の各種電気量の中から、各負荷フィーダーの有効電力Ｐ_Lあるいは各発電機の有効電力Ｐ_Gを用いて、制御対象を選択する。
【０２１５】
ここで、周波数低下側において負荷制限の対象を決定する場合を例にとって説明すると、有効電力Ｐ_Lの大きな負荷フィーダーから順次解列対象として選択し、選択された負荷フィーダーの有効電力Ｐ_Lの合計値Ｐ_LTと制御量を比較して、合計値Ｐ_LTが制御量（Ｐ_CUTあるいはＰ_CUT1あるいはＰ_CUT2）と同様か、大きくなったら、解列対象の選択を止め、それまでに選択した負荷フィーダーを解列対象として決定する。一方、周波数上昇側の場合は、有効電力Ｐ_Gの大きな発電機から順次解列対象として選択する。
【０２１６】
また、解列した場合に系統運用上あるいは需要家に対して影響が大きいかどうかを表わす重要度や解列した際の周波数低下あるいは上昇の抑止効果の大きさなど基にして遮断の優先順位を決め、この優先順位の高いものから順に制御対象として選択してもよい。
【０２１７】
この場合も、例えば、周波数低下側を例にとって説明すると、優先順位の高いものから順次解列対象として選択し、選択された負荷フィーダーの有効電力Ｐ_Ｌの合計値Ｐ_LTと制御量（Ｐ_CUTあるいはＰ_CUT1あるいはＰ_CUT2）を比較して、合計値Ｐ_LTが制御量と同様か、大きくなったら、解列対象の選択を止め、それまでに選択した負荷フィーダーを解列対象として決定する。
【０２１８】
制御部４では、制御量演算部３の制御対象決定手段３４の選択結果に基づいて、解列対象の負荷フィーダーあるいは発電機が接続されている遮断器に対して、開放指令を出力し、負荷制限を実施することで周波数低下あるいは上昇を防止する。
【０２１９】
なお、第３の実施の形態乃至第１１の実施の形態の各手段と適宜組み合わせて、周波数演算部２及び制御量演算部３を図２３に示すような構成としてもよい。個々の手段の作用は、第３の実施の形態形態乃至第７の実施の形態形態と同様であるので説明を省略する。
【０２２０】
このように本発明の第１２の実施の形態によれば、系統より解列する負荷フィーダーあるいは発電機を自動的に選択できるので、運用性に優れた装置とすることができる。
【０２２１】
次に、本発明の第１３の実施の形態の電力系統の周波数安定化装置について、図２４乃至図２９を参照しながら説明する。
【０２２２】
本発明の第１３の実施の形態の電力系統の周波数安定化装置は、第１の実施の形態または第２の実施の形態に記載の電力系統の周波数安定化装置において、監視対象の電気所が属するローカル系統と電力系統のその他の系統（主系統）との間の連系線の遮断器の開閉情報と電流，電圧，有効電力などを含む各種電気量とローカル系統内の発電機が運転されているかどうかを示す発電機の解併列情報を測定あるいは収集すると共に、予め設定し保管したローカル系統内の発電機の定格出力，慣性定数などを含む各種発電機情報と前記収集した発電機の解併列情報を用いて、連系線上からみたローカル系統側を１機の等価発電機モデルで表わした場合の等価発電機モデルの慣性定数を、所定の演算により算出し、算出した慣性定数を需給アンバランス量を推定する際に用いる発電機の慣性定数とするようにした点に特徴を有している。
【０２２３】
図２４は、本発明の第１３の実施の形態の電力系統の周波数安定化装置の全体構成図、図２５は、系統状態推定部の構成図である。
【０２２４】
図２４において、監視対象の電気所１０７が属するローカル系統１０３と電力系統のその他の系統（主系統１０１）とを連系する送電線１０２を接続する電気所１０７端に、系統状態推定部１３０（図示黒塗部分）を設置して、ローカル系統１０３内の監視対象とする各電気所１０７毎に、系統状態計測部１と周波数演算部２と制御量演算部３と制御部４と系統状態記憶部５を一つのセットとしてそれぞれ設置して、情報通信網である通信ネットワーク１１５で接続し、必要な情報をお互いに送受信する。
【０２２５】
系統状態推定部１３０は、図２５に示すように、連系線１０２の電流，電圧，有効電力，遮断器１０６の開閉情報を入力する一方、発電機の解併列情報を入力して系統状態を推定し、推定した慣性定数を情報通信装置１１４から通信ネットワーク１１５へ出力する。
【０２２６】
系統状態推定部１３０は、図２６に示す具体例のように、連系線状態計測手段６１と発電機運転状態把握手段６２と慣性定数演算手段６３と系統構成把握手段６４と発電機情報記憶手段６５とから構成されている。
【０２２７】
系統状態推定部１３０の連系状態計測手段６１では、連系線１０２の遮断器１０６の開閉情報と電流，電圧，有効電力などを含む各種電気量を時々刻々と計測あるいは収集し、系統状態推定部１３０の系統構成把握手段６４に渡す。
【０２２８】
次に、発電機運転状態把握手段６２では、発電機の運転状態を示す発電機の解併列情報、つまり、発電機が接続されている遮断器の開閉情報を、ローカル系統内の監視対象とする発電所毎に設置した系統状態計測部１を介して収集し、慣性定数演算手段６３へ渡す。
【０２２９】
次に、発電機情報記憶手段６５では、ローカル系統内の発電機の定格出力，慣性定数などを含む各種発電機情報を予め設定し保管しておき、必要に応じて各手段に出力する。図２９は、発電機情報記憶手段６５の発電機情報のデータベースの概念図である。
【０２３０】
次に、慣性定数演算手段６３では、発電機情報記憶手段６５に保管した発電機の定格出力，慣性定数などを含む各種発電機情報と発電機運転状態把握手段６２にて収集した発電機の解併列情報を用いて、連系線上からみたローカル系統１０３側を１機の等価発電機モデルで表わした場合の等価発電機モデル１１２の慣性定数Ｍを、所定の演算により算出する。
【０２３１】
具体的には、発電機の解併列情報からローカル系統１０３に接続されている発電機を確認して、系統に接続されている発電機の定格出力，慣性定数などの各種発電機情報を発電機情報記憶手段６５から呼び出して用いて、次の（１３．１）式から慣性定数を定格出力で加重平均した値Ｍ_CALを演算により求める。
【０２３２】
【数１６】

【０２３３】
ここで、ｍは、分離系統内で運転している発電機の総数。ｎは、発電機の通し番号（図２９のｎと同様）。
【０２３４】
次に、系統構成把握手段６４では、連系線状態計測手段６１で収集した連系線の遮断器の開閉情報を用いて、連系線の遮断器が開放されてローカル系統１０３が分離系統となっていることを確認する。そして、分離系統となっている場合には、慣性定数演算手段６３で求めた等価発電機モデル１１２の慣性定数Ｍ_CALを、ローカル系統１０３内の監視対象の電気所毎に設置したそれぞれの制御量演算部３へ渡す。
【０２３５】
監視対象の電気所毎に設置したそれぞれの制御量演算部３において、需給アンバランス量を推定する際に用いる前述した（１．１）式中の慣性定数Ｍに、慣性定数演算手段６３で算出した慣性定数Ｍ_CALを用いて需給アンバランス量を推定する。
【０２３６】
なお、ここで、遮断されると分離系統となる連系線がローカル系統内に複数個所ある場合には、慣性定数Ｍ_CALを次のようにして求める。
【０２３７】
まず、各連系線がそれぞれ遮断された場合の分離系統の系統構成を事前に調査すると共に、各連系線がそれぞれ遮断された場合に分離系統内にどの発電機が属するのかを調査する。そして、各連系線遮断ケース毎に、図２９に示すようなデータベース作成し、発電機情報記憶手段６５において予め設定し保管しておく。連系線状態計測手段６１では、各連系線の遮断器の開閉情報を収集して、系統構成把握手段６４に渡す。
【０２３８】
発電機運転状態把握手段６２では、ローカル系統１０３内の監視対象とする発電所毎に設置した系統状態計測部１によって発電機の運転状態を示す発電機の解併列情報を収集し、慣性定数演算手段６３へ渡す。
【０２３９】
系統構成把握手段６４では、収集した連系線の遮断器の開閉情報を用いて、遮断された連系線を確認して、その結果を慣性定数演算手段６３に渡す。
【０２４０】
慣性定数演算手段６３では、系統構成把握手段６４の結果を用いて、発電機情報記憶手段６５に予め設定し保管しておいた複数のデータベースの中から、遮断された連系線に対応するデータベースを選択して、演算に用いる。
【０２４１】
選択された発電機情報記憶手段６５に保管の発電機の定格出力，慣性定数などの各種発電機情報と収集した発電機の解併列情報を用いて、分離系統に接続されている発電機を確認して、等価発電機モデル１１２の慣性定数Ｍ_CALを、前述する（１３．１）式から演算により算出する。
【０２４２】
図２７及び図２８は、系統状態推定部１３０と組み合わせる周波数安定化装置の構成図である。
【０２４３】
図２７の場合には、系統状態推定部１３０によって得られた等価発電機モデル１１２の慣性定数Ｍ_CALが制御量演算部３の初期制御演算手段３１’及び補正制御演算手段３２の演算に用いられる。
【０２４４】
また、図２８の場合には、系統状態推定部１３０によって得られた等価発電機モデル１１２の慣性定数Ｍ_CALが主制御演算手段３１の演算に用いられる。
【０２４５】
このように本発明の第１３の実施の形態によれば、需給アンバランス量を推定する際に用いる等価発電機モデルの慣性定数を正確に算出できるので、高精度の装置とすることができる。
【０２４６】
次に、本発明の第１４の実施の形態の電力系統の周波数安定化装置の各構成部及び手段の作用を、図１と図３０乃至図３４を参照しながら説明する。
【０２４７】
本発明の第１４の実施の形態の電力系統の周波数安定化装置は、第２の実施の形態に記載の電力系統の周波数安定化装置において、分離系統内の一部の周波数安定化装置が故障などにより不動作であった場合に、正動作する装置において、故障装置が実施すべき負荷制限あるいは電源制限分を考慮して制御を実施するようにしている。図３１は、本発明の第１４の実施の形態の電力系統の周波数安定化装置の一実施例の構成図である。
【０２４８】
次に、全体の処理の流れを図３０乃至図３４を用いて説明する。なお、系統状態計測部１、周波数演算部２、制御部４及び系統状態記憶部５の作用と、制御量演算部３の以下に説明する手段以外の作用は、第１の実施の形態と同じであるので説明を省略する。
【０２４９】
本周波数安定化装置は、図３１に示すようにローカル系統内の監視対象とする各電気所に本装置を分散配置して、それぞれの装置毎にローカル系統内の需給アンバランス量を推定して、推定した需給アンバランス量に基づいて負荷制限量あるいは電源制限量を算出し、制御を実施してローカル系統内の需給アンバランスを解消し、周波数低下あるいは上昇が発生する前の定常時の周波数（基準周波数）に制御する。
【０２５０】
しかし、ローカル系統内の一部の周波数安定化装置において装置故障等が発生し制御が実施されないと、ローカル系統全体としては制御量が不足し、周波数低下あるいは上昇し続ける可能性が考えられる。このため、正動作する残りの周波数安定化装置において、故障した装置が制御すべき制御量分を多く制御すれば、不足分は解消されるので、周波数低下あるいは上昇を抑制して、周波数低下あるいは上昇が発生する前の定常時の周波数（基準周波数）に制御可能である。
【０２５１】
以下に、誤不動作装置があった場合の正動作する装置側での処理を説明する。正動作装置において不足分を考慮して制御を実施する必要がある場合は、次のような場合が考えられる。例えば、自端以外の不特定多数の装置で装置故障等が発生し、初期制御及び追加制御が共に実施されなかった場合あるいは全装置とも初期制御は正動作し、追加制御が自端以外の不特定多数の装置で実施されなかった場合などが考えられる。
【０２５２】
まず初めに、正動作する周波数安定化装置の制御演算開始判定手段３０において、計測した周波数などの各種電気量と予め設定した所定の条件を用いて、追加制御を実施するか、実施しないかの判定を行う。例えば、計測した周波数を用いて追加制御を実施するか、実施しないかの判定を行う場合には、予め設定した動作判定しきい値ｆ_LMと初期制御後の周波数ｆを比較すると共に、周波数変化率ｄｆ／ｄｔを観測して、以下のように判定する。
【０２５３】
ｄｆ／ｄｔ≦０、且つ、ｆがｆ_LM以内ならば追加制御不要と判定 （１４．１）ｄｆ／ｄｔ＞０、且つ、ｆがｆ_LM超ならば追加制御必要と判定 （１４．２）ここで、ｄｆ／ｄｔは、周波数上昇側では、上昇傾向のとき正とする。周波数低下側では、低下傾向のとき正とする。
【０２５４】
“追加制御必要と判定”した場合には、補正制御演算手段３２で、不足制御分を含めた初期制御実施後のローカル系統内の需給アンバランス量ΔＰ_C2を推定し、推定したΔＰ_C2に応じた追加制御量Ｐ_CUT2を決定する。
【０２５５】
以下に、不足制御分を含めた需給アンバランス量ΔＰ_C2の推定方法を説明する。例えば、周波数低下側で自端以外の不特定多数の装置で初期制御及び追加制御が共に実施されなかった場合を例にとって説明する。
【０２５６】
図３１に示すようなローカル系統において、ローカル系統内の負荷変電所Ａ１からＡ５にそれぞれＰ_L1からＰ_L5の負荷があり、各負荷変電所でほぼ一律に負荷をα（＝ΔＰ_C1）［％］づつ遮断したとすると、ローカル系統全体の制御量Ｐ_C1Tは（１４．３）式のようになる。なお、Ｐ_Ln・ΔＰ_C1が、各電気所における制御量である。
【０２５７】
【数１７】

【０２５８】
次に、誤不動作装置があると仮定した場合、図３２に示すように、このときの正動作装置の割合をβとし、β＝（１−誤不動作装置の割合）と定義する。例えば、負荷変電所Ａ１からＡ３の装置が正動作して、その割合βが６０［％］であったとすると、（１−β）＝（１−０．６）＝４０［％］が誤不動作装置の割合（Ａ４とＡ５）となる。
【０２５９】
正動作装置において、不動作分を含んだ制御を実施することを考えると、（１４．４）式に示すように自端で１／β分多く制御すれば不足分を補うことができる。
【０２６０】
【数１８】

【０２６１】
よって、不特定多数の誤不動作装置があった場合の初期制御後の需給アンバランス量ΔＰＣ２の推定式は、初期制御がβ［％］しか制御されていないことを考慮すると（１４．５）式となる。つまり、（２．１３）式をそのまま用いれば良い。なお、簡単のため負荷の増減特性係数ａ_afを考慮しない推定式を用いた。
【０２６２】
負荷の増減特性係数ａ_bf，ａ_afを考慮した場合も同様に、ΔＰ_C2の推定式は、初期制御がβ［％］しか制御されていないことを考慮すると（１４．６）式あるいは（１４．７）式となり、（２．３）式あるいは（２．１８）式をそのまま用いれば良いことがわかる。
【０２６３】
【数１９】

【０２６４】
本実施の形態によれば、誤不動作装置が不特定多数あった場合でも、正動作装置において不足制御分を含めた制御量を算出できるので、システムとして信頼性の高い周波数安定化装置を提供できる。
【０２６５】
また、本第１４の実施の形態の電力系統の周波数安定化装置では、監視対象の電気所が属する系統内の一部の電気所にのみ本周波数安定化装置を設置するようにした場合にも、対応することができる。図３３は、この場合の電力系統の周波数安定化装置の一実施例の構成図である。
【０２６６】
以下に、全体的な処理の流れを図３３と図３４を用いて説明する。なお、系統状態計測部１及び周波数演算部２及び制御部４及び系統状態記憶部５の作用と、制御量演算部３の以下に説明する手段以外の作用は、第２の実施の形態と同じであるので説明を省略する。
【０２６７】
本実施の形態では、図３３に示すようにローカル系統内の一部の電気所にのみ本周波数安定化装置を設置して、それぞれ装置毎におのおの独立して周波数を監視し、対策が必要な場合には制御量の算出と制御を実施する。
【０２６８】
しかし、第２の実施の形態の電力系統の周波数安定化装置は、ローカル系統内に属する全ての電気所において、一律の制御が実施されないと、ローカル系統全体としては制御量が不足し、周波数低下あるいは上昇し続ける可能性が考えられる。このため、本実施の形態では、一部の電気所にのみ周波数安定化装置を設置するシステム構成として、各周波数安定化装置において、周波数安定化装置が設置されていない電気所で制御すべき制御量分を含んだ制御量を算出するようにする。
【０２６９】
以下に、処理を説明する。まず、初期制御演算手段３１’にて、監視対象の電気所が属するローカル系統の需給アンバランス量ΔＰ_C1を所定の演算により推定し、推定した需給アンバランス量ΔＰ_C1と電気所内の定常時の総負荷量あるいは総発電量（＝Ｐ_LOT）を用いて初期制御量Ｐ_CUT1を算出する。具体的な作用は、第１の実施の形態と同じであるので説明を省略する。
【０２７０】
次に、制御演算開始判定手段３０において、追加制御を実施するか、実施しないかの判定を行う。具体的な作用は、図３１，図３２で説明した誤不動作の周波数安定化装置がある場合と同じであるので説明を省略する。なお、“追加制御必要と判定”した場合には、補正制御演算手段３２では、本装置が設置されていない電気所分も考慮した初期制御実施後の需給アンバランス量ΔＰ_C2を推定して、推定したΔＰ_C2に応じて追加制御量Ｐ_CUT2を決定する。
【０２７１】
具体的には、例えば、周波数低下側を例にとって説明すると、図３３に示すようなローカル系統において、ローカル系統内の負荷変電所Ａ１からＡ５にそれぞれＰ_L1からＰ_L5の負荷があり、負荷変電所Ａ１からＡ３に本周波数安定化装置を分散設置して監視・制御しているとする。次に、図３１，図３２で説明した正動作装置の割合βについて、装置が設置されている＝正動作装置があるのと同じ，装置が設置されていない＝誤不動作装置があるのと同じ，と考え、本装置が設置されている電気所で制御すべき制御量を考えると、（１４．４）式に示す通り、自端で１／β分多く制御すれば不足分を補うことができる。同様に、装置が設置されていない電気所分を考慮した初期制御後の需給アンバランス量ΔＰ_C2の推定式を考えると、初期制御量Ｐ_CUT1は、ローカル系統全体でみればβ［％］しか制御されていないことを考慮すると、やはり（１４．５）式乃至（１４．７）式に示すようになる。
【０２７２】
つまり、一部の電気所にのみ本装置が設置されるシステム構成の場合でも、装置が設置されている電気所で１／β分多く制御すれば不足分を補うことができるので、一部の電気所にのみ本装置を設置する形態の場合の推定式は、ローカル系統内の全ての電気所に本周波数安定化装置を設置した場合の推定式（２．３）式あるいは（２．１８）式と同じとなる。
【０２７３】
これらのことから、監視対象外の負荷が存在した場合や、発電所の所内負荷などのような制御不可能な負荷あるいは送電損失の有効電力分Ｐ_LOSSなどが存在した場合でも、それらに対する制御量も含んだ追加制御量が本装置で算出できることがわかる。
【０２７４】
本実施の形態によれば、電力系統内の一部の電気所にのみ本装置を設置することで、ローカル系統の周波数低下あるいは上昇を抑制し、基準周波数に制御できるので、システムを簡素化できる。また、監視対象外の負荷や制御不可能な負荷あるいは送電損失などが存在した場合でも、これらに対する制御量も含め追加制御量を算出できるので、信頼性や運用性の高い周波数安定化装置を提供できる。
【０２７５】
次に、本発明の第１５の実施の形態の電力系統の周波数安定化装置の各構成部及び手段の作用を、図１と図２と図３５を参照しながら説明する。
【０２７６】
本発明の第１５の実施の形態の電力系統の周波数安定化装置は、第２の実施の形態の電力系統の周波数安定化装置の制御量演算部において、求めた周波数変化率を用いて、制御目標周波数を見直すようにしている。図３５は、制御量演算部の構成図である。
【０２７７】
次に、全体の処理の流れを図２と図３５を用いて説明する。なお、系統状態計測部１及び周波数演算部２及び制御部４及び系統状態記憶部５の作用と制御量演算部３の以下に説明する手段以外の作用は、第２の実施の形態と同じであるので説明を省略する。
【０２７８】
制御目標周波数設定手段３０１では、周波数変化率ｄｆ／ｄｔと予め設定した制御目標周波数切り換えしきい値Δｆ_TRGを用いて、周波数変化率の大きさに応じて制御目標周波数を切り換える。
【０２７９】
ｄｆ／ｄｔ≧Δｆ_TRG ならば、
制御目標周波数を基準周波数に設定 ・・・・（１５．１）
ｄｆ／ｄｔ＜Δｆ_TRG ならば、
制御目標周波数を初期制御実施時点の周波数に設定・・・（１５．２）
【０２８０】
「制御目標周波数を基準周波数に設定」と判定した場合には、第１の実施の形態において説明した方法で初期制御量Ｐ_CUT1と追加制御量Ｐ_CUT2を求める。
【０２８１】
「制御目標周波数を初期制御実施時点の周波数に設定」と判定した場合には、追加制御量Ｐ_CUT2を以下の通り算出する。
【０２８２】
ΔＰ_C1の推定方法は、第２の実施の形態と同じであるので説明を省略する。初期制御量Ｐ_CUT1は、推定した需給アンバランス量ΔＰ_C1と初期制御直前の電気所内の総負荷量あるいは総発電量（＝Ｐ_LC1T）を用いて（１５．３）式から算出する。
【０２８３】
Ｐ_CUT1＝Ｐ_LCIT・ΔＰ_C1 ・・・・（１５．３）
【０２８４】
次に、補正制御演算手段３２では、第２の実施の形態で説明したようにΔＰ_C2を推定する。追加制御量Ｐ_CUT2は、推定した需給アンバランス量ΔＰ_C2と初期制御直前の電気所内の総負荷量あるいは総発電量（＝Ｐ_LC1T）を用いて（１５．４）式から算出する。
【０２８５】
Ｐ_CUT2＝Ｐ_LCIT・ΔＰ_C2 ・・・・（１５．４）
【０２８６】
このようにして求めた追加制御量Ｐ_CUT2を制御部４へ渡すと共に、系統状態記憶部５において保管する。
【０２８７】
「制御目標周波数を初期制御実施時点の周波数に設定」の場合には、補正制御演算で、初期制御実施時点の周波数に制御するための制御量を算出する。つまり、初期制御実施時点のローカル系統内の総負荷量と総発電量のアンバランスを推定することになる。一方、「制御目標周波数を基準周波数に設定」の場合は、基準周波数に制御するための制御量を算出する。つまり、系統分離発生時のアンバランス（ローカル系統内の定常時の総需要に対する遮断された連系線事前潮流の割合）を推定することになる。前者の特徴は、初期制御時点の需給アンバランスと同量の制御を行って、まず、周波数低下あるいは上昇を防止し、本装置以外の制御（例えば、発電機の出力増加・低下など）によって、基準周波数に安定化するものであり、後者は、初期の需給アンバランス、つまり、連系線事前潮流分の等量制御を行って、基準周波数に安定化する。
【０２８８】
本実施の形態によれば、周波数変化率によって目標制御周波数を選択するので、周波数低下率が大きく制御の緊急性が高い場合には制御量が多く算出され、周波数抑止効果が高くなる。また、周波数低下率が小さく安定化制御の緊急性が低い場合には制御量が少なく算出され、発電機の出力増加の制御により基準周波数に制御するので、停電区間を最小化できる。
【０２８９】
次に、本発明の第１６の実施の形態の電力系統の周波数安定化装置の各構成部及び手段の作用を図１、図２と図３０、図３６を参照しながら説明する。
【０２９０】
本発明の第１６の実施の形態の電力系統の周波数安定化装置は、まず第１番目として、第２の実施の態様の電力系統の周波数安定化装置の制御量演算部において、負荷フィーダーあるいは発電機の有効電力から算出した係数を用いて、算出した周波数変化率などの各種電気量の変化分や計測した周波数などを補正するようにしている。図３６は、その制御量演算部の構成図である。
【０２９１】
次に、全体の処理の流れを説明する。なお、系統状態計測部１及び周波数演算部２及び制御部４及び系統状態記憶部５の作用と制御量演算部３の以下に説明する手段以外の作用は、第２の実施の形態と同じであるので説明を省略する。
【０２９２】
具体的には、周波数補正手段３０２において、周波数演算部２で求めた周波数変化率ｄｆ／ｄｔを、負荷の増減特性係数ａ_bf，ａ_afを用いて、（１６．１）式乃至（１６．３）式のように補正する。なお、負荷の増減特性係数ａ_bf，ａ_afの算出方法は、第２の実施の形態と同じであるので説明を省略する。
【０２９３】
α＝Ｋ_ADJ2・ａ_bf ・・・・（１６．１）
あるいは
α＝Ｋ_ADJ2・ａ_af ・・・・（１６．２）
Δｆ_RE＝α・Δｆ ・・・・（１６．３）
【０２９４】
ここで、Δｆは、周波数変化率ｄｆ／ｄｔであり、添字のＲＥは補正後の値であることを示す。Ｋ_ADJ2は、予め設定した係数である。系統分離直後は、（１６．１）式を使用し、初期の負荷制限あるいは追加の負荷制限直後には、（１６．２）式を用いる。
【０２９５】
本実施の形態によれば、需給アンバランス量を推定する際に用いる周波数変化率を、負荷の増減特性を表わす係数を用いて自動的に補正するため、負荷の電圧特性により負荷量が増加した場合でも精度よく追加制御量を算出できるので、推定精度の高い電力系統の周波数安定化装置を提供できる。
【０２９６】
次に、本実施の形態の第２番目として、第２の実施の形態の電力系統の周波数安定化装置の制御量演算部の周波数補正手段３０２において、電圧から算出した係数を用いて、算出した周波数変化率などの各種電気量の変化分や計測した周波数などを補正するようにしている。
【０２９７】
具体的には、周波数補正手段３０２において、周波数演算部２で求めた周波数変化率ｄｆ／ｄｔを、電圧変動係数ａ_bfv，ａ_afvを用いて（１６．４）式乃至（１６．６）式のように補正する。なお、電圧変動係数ａ_bfv，ａ_afvの算出方法は、第２の実施の形態と同じであるので説明を省略する。
【０２９８】
α＝Ｋ_ADJ3・ａ_bfv ・・・・（１６．４）
あるいは
α＝Ｋ_ADJ3・ａ_afv ・・・・（１６．５）
Δｆ_RE＝α・Δｆ ・・・・（１６．６）
【０２９９】
ここで、Δｆは、周波数変化率ｄｆ／ｄｔであり、添字のＲＥは補正後の値であることを示す。Ｋ_ADJ3は、予め設定した係数である。系統分離直後は、（１６．４）式を使用し、初期の負荷制限あるいは追加の負荷制限直後には、（１６．５）式を用いる。
【０３００】
本実施の形態によれば、需給アンバランス量を推定する際に用いる周波数変化率を、電圧変動特性を表わす係数を用いて自動的に補正するため、系統分離後の電圧低下や制御を実施した際に発生する電圧上昇の影響を除去でき精度よく追加制御量を算出できるので、推定精度の高い電力系統の周波数安定化装置を提供できる。
【０３０１】
次に、本発明の第１７の実施の形態の電力系統の周波数安定化装置の各構成部及び手段の作用を図１、図２、図４と図３７を参照しながら説明する。
【０３０２】
本発明の第１７の実施の形態の電力系統の周波数安定化装置は、第２の実施の態様の電力系統の周波数安定化装置の制御量演算部において、監視対象の電気所が属する系統内の発電機の慣性定数を推定するようにした。図３７は、本発明に係わる電力系統の周波数安定化装置の制御量演算部の一実施例の構成図である。
【０３０３】
以下に、全体の処理の流れを説明する。なお、系統状態計測部１及び周波数演算部２及び制御部４及び系統状態記憶部５の作用と制御量演算部３の以下に説明する手段以外の作用は、第２の実施の形態と同じであるので説明を省略する。
【０３０４】
図３７に示す慣性定数推定手段３５では、前述の（２．１０）式を用いて、連系線上からみたローカル系統側を図４に示すような１機の発電機で表わした際の等価発電機モデルの慣性定数Ｍを推定する。なお、（２．１０）式において、有効電力から算出した負荷増減特性係数ａ_bf，ａ_afの代わりに、計測した電圧から算出した負荷特性増減係数ａ_bfv，ａ_afvを用いてもよい。初期負荷制限後の負荷量Ｐｅ（ｔ＋）は、第２の実施の形態で説明したように、電気所内の定常時の総負荷量Ｐ_LOTから初期制御量Ｐ_CUT1分遮断したものであり、よって、Ｐｅ（ｔ＋）＝Ｐ_L（ｔ＋）＝（Ｐ_L0−Ｐ_CUT1）＝（１−ΔＰ_C1）、とする。
【０３０５】
推定した慣性定数Ｍ_estは、系統状態記憶部５に保管しておき、後日、周波数低下あるいは上昇が発生した際に、初期制御演算手段３１’において、初期制御前の需給アンバランス量ΔＰ_C1の推定式（１．１）式のＭとして用いる。このようにすれば、実系統の慣性定数を用いることができるので、より高精度に需給アンバランス量を推定できる。
【０３０６】
本実施の形態によれば、監視対象の電気所端のみで計測あるいは収集可能な情報のみで、監視対象の電気所が属する系統内の発電機を１機で表わした場合の等価発電機モデルの慣性定数を推定することができる。
【０３０７】
次に、本発明の第１８の実施の形態の電力系統の周波数安定化装置の各構成部及び手段の作用を図１、図２と図３０、図３８を参照しながら説明する。
【０３０８】
本発明の第１８の実施の形態の電力系統の周波数安定化装置は、第２の実施の形態の電力系統の周波数安定化装置の制御量演算部において、初期あるいは追加の負荷制限あるいは電源制限を実施した前と後の負荷フィーダーあるいは発電機の有効電力から算出した係数を用いて、算出した制御量を補正するようにしている。図３８は、その制御量演算部の構成図である。
【０３０９】
次に、全体の処理の流れを説明する。なお、系統状態計測部１及び周波数演算部２及び制御部４及び系統状態記憶部５の作用とこれから説明する制御量補正演算手段３３以外の制御量演算部３の手段の作用は、第２の実施の形態と同じであるので説明を省略する。
【０３１０】
制御量補正演算手段３３では、算出した制御量Ｐ_CUT（追加制御量Ｐ_CUT2）を、負荷増減特性係数ａ_afを用いて（１８．１）式のように補正する。なお、負荷増減特性係数ａ_afの算出方法は、第２の実施の形態と同じであるので説明を省略する。
【０３１１】
具体的には、負荷増減特性係数ａ_afを用いて、算出した制御量Ｐ_CUTを（１８．１）式を用いて補正する。
【０３１２】
【数２０】

【０３１３】
ここで、α_pcは、予め設定した係数であり、Ｐ_CUTは、追加制御量Ｐ_CUT2である。
【０３１４】
なお、制御量Ｐ_CUTを補正する代わりに、推定した需給アンバランス量ΔＰ（ΔＰ_C1あるいはΔＰ_C2）を上記方法にて補正し、補正後のΔＰを用いて制御量Ｐ_CUTを算出してもよい。
【０３１５】
本実施の形態によれば、負荷の増減特性を表わす係数を用いて制御量を自動的に補正するので、負荷の電圧特性により負荷量が変化した場合でも精度よく追加制御量を算出できるので、負荷の電圧特性を考慮した推定精度の高い電力系統の周波数安定化装置を提供できる。
【０３１７】
【発明の効果】
請求項１の発明によれば、遮断済みの制御量の合計値と周波数変化率のみで、監視対象の電気所が属する系統内の需給アンバランス量を推定できるので、演算のためのパラメータ設定が必要なく、また、推定した需給アンバランス量から制御量を算出するので需要の増減などの系統状態が変化しても対応でき、系統運用者の負担を低減でき、また、追加制御を繰り返し実施するので不足制御を防止できる。また、監視対象の電気所端のみで計測あるいは収集可能な情報のみで、需給アンバランス量を推定し、推定した需給アンバランス量に基づいて制御量を算出できるので、電力系統内の各所において計測した情報を収集する必要がなく広域の情報伝送網も不要で、システム規模を小さくできる。また、監視対象の電気所毎に個別に監視，制御が実施できるので、装置構成が簡素で制御性が高く運用性や保守性に優れた装置を提供できる。
【０３１８】
また、請求項２の発明によれば、系統分離に伴う電圧変化によるローカル系統内の負荷の増減とか、ローカル系統内の負荷制限や電源制限に伴う電圧変動による負荷の増減をそれぞれ考慮した需給アンバランスの推定を行えるので、推定精度を高めることができる。また、電圧変動の影響を除去するための周波数の平滑化処理を削除あるいは平滑化処理に用いるデータ区間長の短縮を図ることができため、追加制御量を短時間に算出できる。
【０３１９】
また、請求項３の発明によれば、計測した電圧から算出した電圧変動係数として、負荷の増減特性係数を求めることにより、電圧変動を考慮した需給アンバランス量の推定を行えるので、推定精度を高めることができる。また、電圧変動の影響を除去するための周波数の平滑化処理を削除あるいは平滑化処理に用いるデータ区間長の短縮を図ることができため、追加制御量を短時間に算出できる。
【０３２０】
また、請求項４の発明によれば、需給アンバランス量を求める際に用いる各種電気量に平滑化処理を施しているので、周波数が異常に変動する場合でも、精度良く需給アンバランス量を推定でき、且つ、推定結果のばらつきを防止するので、高精度で高信頼度の装置を提供できる。
【０３２１】
また、請求項５の発明によれば、予測した将来の周波数やその周波数変化率を用いて演算を行うので、実測値を用いて演算する場合より早い時点で演算結果を得ることができ、早い時点で制御を実施でき、周波数の異常変動を短時間で安定化する装置とすることができる。
【０３２２】
また、請求項６の発明によれば、予め設定した条件を基にして、段階的に制御が実施できるので、系統運用に合わせた制御が可能であり運用性の高い装置とすることができる。
【０３２３】
また、請求項７の発明によれば、複数の周波数安定化装置間で動作条件を違えることができるので、協調を取った安定化制御により必要以上の解列を防止できる。
【０３２４】
また、請求項８の発明によれば、負荷制限後の過渡的な電圧上昇が発生している間は、補正制御演算をロックするので、電圧上昇に伴って負荷の消費電力が増加し過剰に制御量が算出される場合でも、過剰制御を防止できる。
【０３２５】
また、請求項９の発明によれば、負荷制限後の過渡的な電圧上昇が発生している間は、補正制御演算をロックするので、電圧上昇に伴って負荷の消費電力が増加し過剰に制御量が算出される場合でも、過剰制御を防止できる。
【０３２６】
また、請求項１０の発明によれば、需給アンバランス量を推定する際に用いる等価発電機モデルの慣性定数を、周波数変化率の大きさを用いて調整するので、実現象に応じた制御量を算出できる。
【０３２７】
また、請求項１１の発明によれば、需給アンバランス量を推定する際に用いる等価発電機モデルの慣性定数を、周波数変化率の大きさを用いて調整するので、実現象に応じた制御量を算出できる。
【０３２８】
また、請求項１２の発明によれば、計測した各種電気量を用いて制御量を補正するので、実現象に即した制御量を算出でき、運用性の高い装置とすることができる。
【０３２９】
また、請求項１３の発明によれば、系統より解列する負荷フィーダーあるいは発電機を選択できるので、運用性に優れた装置とすることができる。
【０３３０】
また、請求項１４の発明によれば、需給アンバランス量を推定する際に用いる等価発電機モデルの慣性定数を正確に算出できるので、高精度の装置とすることができる。
【０３３１】
また、請求項１５の発明によれば、誤不動作装置が不特定多数あった場合でも、正動作装置において不足制御分を含めた制御量を算出できるので、システムとして信頼性の高い周波数安定化装置を提供できる。
【０３３２】
また、請求項１６の発明によれば、電力系統内の一部の電気所にのみ本装置を設置することで、ローカル系統の周波数低下あるいは上昇を抑制し、基準周波数に制御できるので、システムを簡素化できる。また、監視対象外の負荷や制御不可能な負荷あるいは送電損失などが存在した場合でも、これらに対する制御量も含め追加制御量を算出できるので、信頼性や運用性の高い周波数安定化装置を提供できる。
【０３３３】
また、請求項１７の発明によれば、周波数変化率によって目標制御周波数を選択するので、周波数低下率が大きく制御の緊急性が高い場合には制御量が多く算出され、周波数抑止効果が高くなる。また、周波数低下率が小さく安定化制御の緊急性が低い場合には制御量が少なく算出され、発電機の出力増加の制御により基準周波数に制御するので、停電区間を最小化できる。
【０３３４】
また、請求項１８の発明によれば、需給アンバランス量を推定する際に用いる周波数変化率を、負荷の増減特性を表わす係数を用いて自動的に補正するため、負荷の電圧特性により負荷量が増加した場合でも精度よく追加制御量を算出できるので、推定精度の高い電力系統の周波数安定化装置を提供できる。
【０３３５】
また、請求項１９の電力系統の周波数安定化装置によれば、需給アンバランス量を推定する際に用いる周波数変化率を、電圧変動特性を表わす係数を用いて自動的に補正するため、電圧変動の影響を除去でき精度よく追加制御量を算出できるので、推定精度の高い電力系統の周波数安定化装置を提供できる。
【０３３６】
また、請求項２０の発明によれば、監視対象の電気所端のみで計測あるいは収集可能な情報のみで、監視対象の電気所が属する系統内の発電機を１機で表わした場合の等価発電機モデルの慣性定数を推定することができる。
【０３３７】
また、請求項２１の発明によれば、負荷の増減特性を表わす係数を用いて制御量を自動的に補正するので、負荷の電圧特性により負荷量が変化した場合でも精度よく追加制御量を算出できるので、負荷の電圧特性を考慮した推定精度の高い電力系統の周波数安定化装置を提供できる。
【図面の簡単な説明】
【図１】本発明を適用する電力系統の周波数安定化装置の全体構成図である。
【図２】本発明の電力系統の周波数安定化装置の実施の形態を示す構成図である。
【図３】本発明の第１の実施の形態に係わる電力系統の周波数安定化装置の構成図である。
【図４】本発明を適用する電力系統の周波数安定化装置が扱う等価系統モデルを示す図である。
【図５】本発明の第２の実施の形態に係わる電力系統の周波数安定化装置の構成図である。
【図６】本発明の負荷の増減特性係数の概念図である。
【図７】本発明の第３の実施の形態に係わる電力系統の周波数安定化装置の構成図である。
【図８】本発明の第４の実施の形態に係わる電力系統の周波数安定化装置の構成図である。
【図９】図８の他の実施の形態に係わる電力系統の周波数安定化装置の構成図である。
【図１０】本発明の第５の実施の形態に係わる電力系統の周波数安定化装置の構成図である。
【図１１】図１０の電力系統の周波数安定化装置の処理を示す第１フローチャートである。
【図１２】図１０の電力系統の周波数安定化装置の処理を示す第２フローチャートである。
【図１３】図１０の他の実施の形態に係わる電力系統の周波数安定化装置の構成図である。
【図１４】図１３の電力系統の周波数安定化装置の処理を示す第１フローチャートである。
【図１５】図１３の電力系統の周波数安定化装置の処理を示す第２フローチャートである。
【図１６】図１３の電力系統の周波数安定化装置の別の他の実施の形態に係る電力系統の周波数安定化装置の処理を示す部分フローチャートである。
【図１７】本発明の第９の実施の形態及び第１０の実施の形態に係わる電力系統の周波数安定化装置の構成図である。
【図１８】本発明の第９の実施の形態及び第１０の実施の形態に係わる電力系統の周波数安定化装置の構成図である。
【図１９】本発明の第１１の実施の形態に係わる電力系統の周波数安定化装置の構成図である。
【図２０】図１９の電力系統の周波数安定化装置の他の実施の形態に係る電力系統の周波数安定化装置の構成図である。
【図２１】本発明の第１２の実施の形態に係わる電力系統の周波数安定化装置の構成図である。
【図２２】図２１の電力系統の周波数安定化装置の他の実施の形態に係る電力系統の周波数安定化装置の構成図である。
【図２３】図２２の電力系統の周波数安定化装置の別の他の実施の形態に係る電力系統の周波数安定化装置の構成図である。
【図２４】本発明の第１３の実施の形態に係わる電力系統の周波数安定化装置の全体構成図である。
【図２５】図２４の電力系統の周波数安定化装置に備える系統状態推定部の説明図である。
【図２６】図２５の系統状態推定部の具体的構成図である。
【図２７】図２４の電力系統の周波数安定化装置の具体的構成図である。
【図２８】図２４の電力系統の周波数安定化装置の別の具体的構成図である。
【図２９】図２６の系統状態推定部に備える発電機情報記憶手段の構成図である。
【図３０】本発明の第１４の実施の形態に係わる電力系統の周波数安定化装置の周波数演算部及び制御量演算部の構成図である。
【図３１】本発明の第１４の実施の形態に係わる電力系統の周波数安定化装置の構成図である。
【図３２】正動作する周波数安定化装置の割合βを説明する図である。
【図３３】本発明の第１４の実施の形態に係わる他の電力系統の周波数安定化装置の構成図である。
【図３４】本発明の第１４の実施の形態に係わる電力系統の周波数安定化装置の制御量演算部の構成図である。
【図３５】本発明の第１５の実施の形態に係わる電力系統の周波数安定化装置の制御量演算部の構成図である。
【図３６】本発明の第１６の実施の形態に係わる電力系統の周波数安定化装置の制御量演算部の構成図である。
【図３７】本発明の第１７の実施の形態に係わる電力系統の周波数安定化装置の制御量演算部の構成図である。
【図３８】本発明の第１８の実施の形態に係わる電力系統の周波数安定化装置の制御量演算部の構成図である。
【図３９】従来の電力系統の周波数安定化装置の処理を示すフローチャートである。
【図４０】従来の電力系統の周波数安定化装置の周波数低下側を安定化する場合の動作条件設定例の説明図である。
【符号の説明】
１ 系統状態計測部
２ 周波数演算部
３ 制御量演算部
４ 制御部
５ 系統状態記憶部
２１ 周波数演算手段
２２ 周波数平滑化処理手段
２３ 周波数変動予測手段
３０ 制御演算開始判定手段
３１ 主制御演算手段
３１’ 初期制御演算手段
３２ 補正制御演算手段
３３ 制御量補正演算手段
３４ 制御対象決定手段
３５ 慣性定数推定手段
６１ 連系線状態計測手段
６２ 発電機運転状態把握手段
６３ 慣性定数演算手段
６４ 系統構成把握手段
６５ 発電機情報記憶手段
１００ 電力系統
１０１ 主系統
１０２ 連系線
１０３ ローカル系統
１０４ 伝送ライン
１０５ 安定化制御ライン
１０６ 遮断器
１０７ 電気所
１０８ 送電線
１０９ 発電機
１１０ 負荷
１１１ 計測器
１１２ 等価発電機モデル
１１３ 等価負荷モデル
１１４，１１６ 情報通信装置
１１５ 通信ネットワーク
１２０ 周波数安定化装置
１３０ 系統状態推定部
３０１ 制御目標周波数設定手段
３０２ 周波数補正手段
３１０ 演算条件設定手段
５０ 動作条件設定例[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a frequency stabilization device for a power system that detects a decrease or increase in the frequency of a power system and suppresses a decrease or increase in frequency by disconnecting some loads or generators from the power system.
[0002]
[Prior art]
In the conventional power system frequency stabilization device, the relationship between the operating conditions of the device based on the magnitude of the frequency decrease or increase of the power system and the control amount necessary for suppressing the frequency fluctuation is set in advance. The control amount is determined in comparison with the frequency measured at each substation or power plant to be monitored, and the control is performed to suppress the decrease or increase of the frequency.
[0003]
FIG. 39 shows a processing procedure of the above-described conventional power system frequency stabilizing device.
[0004]
First, in (S1), the relationship between the operating condition of the apparatus and the control amount based on the magnitude of frequency decrease or increase is set in advance. For example, the operation condition setting example 50 shown in FIG. 40 is set. Next, in (S2), the frequency is measured from moment to moment at an electrical station such as a substation or a power plant to be monitored. In (S3), the measured frequency is compared with preset operating conditions.
[0005]
Here, it is determined whether or not the operating condition is satisfied in (S4). If the operating condition is satisfied, the process proceeds to (S5). If not, the process returns to (S2), and (S2) The process of (S3) is continued.
[0006]
In (S5), when the operation condition of the apparatus is established in (S4), the control amount corresponding to the operation condition is controlled. For example, in the condition of FIG. 40, when the frequency measured momentarily decreases to 58.90 Hz or less, the first stage operation condition is satisfied, so the corresponding load limit amount (10%) is cut off.
[0007]
Then, the processes from (S2) to (S4) are continued after the control is executed, and when the next second stage operation condition shown in FIG. 40 is satisfied, the corresponding load limit amount (10%) is further set. Cut off. The processes from (S2) to (S4) are continued until the decrease or increase in frequency is settled. By such a method, frequency reduction or increase is suppressed and the system frequency is stabilized.
[0008]
[Problems to be solved by the invention]
However, since the conventional power system frequency stabilization device described based on FIGS. 39 and 40 sets the operating conditions and control amount of the device in advance, and uses the control amount as a fixed value, There are the following problems.
[0009]
First of all, the demand in the power system changes every moment depending on the season or time zone, so if the control amount is fixed, it may be over-controlled or under-controlled depending on the cross section of the power flow. . In order to prevent excessive or insufficient control, it is only necessary to change the setting of the control amount according to the tidal current section. However, changing the setting according to the tidal current section is a burden on the grid operator each time. Is expected.
[0010]
Second, the operating condition is determined using only the magnitude of the deviation from the reference frequency. However, since the speed and magnitude of the frequency decrease or increase vary depending on the operating state and type of the generator and the type of load connected, if the determination is made using only the magnitude of the frequency decrease or increase, the frequency decrease Alternatively, in the case where the rise changes drastically greatly, depending on the setting of the operating condition, there is a possibility that the operating condition is established one after another and excessive control is performed more than necessary.
[0011]
Third, conventionally, in order to suppress abnormal fluctuations in the frequency within a monitored electric station, various amounts of electricity in a large number of locations in the local system to which the monitored object belongs are collected by a wide-area information transmission network to supply and demand. There is a problem that the scale of the system becomes large due to an information transmission network or the like because the balance must be calculated.
[0012]
Therefore, the present invention can flexibly respond to changes in the system status without changing the parameter settings such as the operating conditions of the device even when the system status changes in order to reduce the burden on the system operator. And it aims at providing the frequency stabilization apparatus of the electric power system which calculates the control amount required in order to stabilize a frequency with high precision.
[0013]
[Means for Solving the Problems]
[0014]
  Claim 1According to the invention, in an electric station such as a substation or a power plant to be monitored by an electric power system, predetermined calculations are performed using various electric quantities including the measured frequency of the system, and fluctuations in the obtained frequency are prevented. In a frequency stabilization device for an electric power system that cuts off a generator or a load by a load restriction amount or a power supply restriction amount required for the operation, the frequency change rate of the monitored electric station and the frequency change rate of the monitored electric station Based on the inertia constant of the equivalent generator, a means for estimating the supply / demand imbalance amount in the system by a predetermined calculation, and an initial load limit amount or an initial load amount according to the supply / demand imbalance amount estimated by the means When the frequency of the system to be monitored fluctuates to a predetermined magnitude after the implementation based on the means for determining the power limit and the initial load limit or the initial power limit , Means for re-estimating the supply-demand imbalance amount in the system using each frequency change rate before and after the implementation and each load limit amount or each power limit amount, and the supply-demand unbalance amount re-estimated by this means Means for determining an additional load limit amount or an additional power supply limit amount according to the method, a re-estimation of the supply and demand imbalance amount of the additional grid determined by this means, and an additional load limit amount or power supply limit amount And a means for carrying out the determination in accordance with a predetermined condition, thereby individually monitoring and controlling each monitoring target electric station. According to this means, since it is possible to estimate the supply and demand imbalance amount in the system to which the monitored electric station belongs only by the total value of the control amount that has been shut off and the frequency change rate, there is no need to set parameters for calculation, In addition, since the control amount is calculated from the estimated supply and demand imbalance amount, it is possible to cope with changes in the system status such as increase or decrease in demand, reducing the burden on the system operator, and additional control is repeatedly performed, so insufficient control Can be prevented. In addition, it is possible to estimate the supply and demand imbalance by using only information that can be measured or collected only at the monitored power station end, and calculate the control amount based on the estimated supply and demand imbalance. It is not necessary to collect the information and a wide-area information transmission network is unnecessary, and the system scale can be reduced. Further, since monitoring and control can be performed individually for each electric station to be monitored, it is possible to provide a device with a simple device configuration, high controllability and excellent operability and maintainability.
[0015]
  Claim 2The invention ofClaim 1In the power system frequency stabilization device described above, when estimating the supply / demand imbalance of the system to which the monitored electrical plant belongs after initial or additional load limitation or power limitation, the load limitation or power limitation Estimate the supply and demand imbalance in the system using the frequency change rate before and after the implementation, each load limit amount or each power limit amount, and the load increase / decrease characteristic coefficient associated with system separation and load limit or power limit. It is a thing. The load increase / decrease characteristic coefficient is calculated from the active power of the load feeder or generator before and after the occurrence of the accident. According to this means, it is possible to estimate supply and demand imbalance in consideration of increase / decrease in load in the local system due to voltage change caused by system separation, or increase / decrease in load due to voltage fluctuation due to load restriction or power supply restriction in local system. Therefore, the estimation accuracy can be increased. Further, since the frequency smoothing process for removing the influence of the voltage fluctuation can be deleted or the data section length used for the smoothing process can be shortened, the additional control amount can be calculated in a short time.
[0016]
  Claim 3The invention ofClaim 2In the frequency stabilization apparatus for a power system described, a load increase / decrease characteristic coefficient associated with system separation and load limitation or power source limitation is calculated based on the measured voltage. According to this means, since the increase / decrease characteristic coefficient of the load is obtained as the voltage fluctuation coefficient calculated from the measured voltage, the supply and demand imbalance amount can be estimated in consideration of the voltage fluctuation, so that the estimation accuracy can be improved.
[0017]
  Claim 4The invention ofClaim 1 or claim 2In any one of the power system frequency stabilization apparatuses described above, a predetermined smoothing process is performed on various types of electricity used for calculating a frequency change rate or calculating an unbalanced amount of supply and demand. According to this means, smoothing processing is applied to various types of electricity used to determine the supply and demand imbalance, so even if the frequency fluctuates in a long or short cycle or changes rapidly in a very short time. Since the supply and demand imbalance amount can be estimated with high accuracy and variations in estimation results are prevented, a highly accurate and highly reliable device can be provided.
[0018]
  Claim 5The invention of claim 1 to claim 1Claim 4In any one of the power system frequency stabilization apparatuses described, a future frequency of the system is predicted, and a future frequency change rate predicted is used to estimate the supply and demand imbalance amount. According to this means, since the calculation is performed using the predicted future frequency and the frequency change rate thereof, the calculation result can be obtained at an earlier time point than when the calculation is performed using the actual measurement value, and the control can be performed at an earlier time point. Since it can be implemented, the apparatus can stabilize the frequency drop or rise in a short time.
[0019]
  Claim 6The invention ofClaims 1 to 3In any one of the described power system frequency stabilization devices, when it is determined that a predetermined condition is set in advance, an initial or additional calculation for estimating the supply and demand imbalance amount is started, and the obtained initial or additional The load limit amount or the power control amount is determined according to the supply / demand imbalance amount. According to this means, control can be performed in stages based on preset conditions, so that control in accordance with system operation is possible and an apparatus with high operability can be obtained.
[0020]
  Claim 7The invention ofClaim 6In the power system frequency stabilization device described, the calculation for estimating the supply and demand imbalance amount individually is started according to the tolerance for frequency fluctuations of a load feeder or a generator connected to each monitored electric station. It is a thing. According to this means, when the frequency stabilizing device of the power system is installed in a plurality of electric stations of the power system, the operating conditions can be made different among the plurality of frequency stabilizing devices. Unnecessary disconnection can be prevented by stabilizing control.
[0021]
  Claim 8The invention ofClaims 1 to 3In any one of the power system frequency stabilizers described above, the initial or additional calculation for estimating the supply / demand imbalance amount is started, and the load restriction amount or the power supply restriction amount is determined by the obtained initial or additional supply / demand imbalance amount. After deciding and carrying out the generator or load cutoff, the calculation for estimating the supply / demand imbalance amount is locked in accordance with a predetermined condition when the calculation for estimating the supply / demand imbalance amount is performed again. Is. According to this means, the correction control calculation is locked while a transient voltage increase after the load is limited, so that the power consumption of the load increases with the voltage increase, and the control amount is excessively calculated. Even in this case, excessive control can be prevented and a highly reliable device can be obtained.
[0022]
  Claim 9The invention ofClaim 8In the frequency stabilization device of the power system described, the initial or additional calculation to estimate the supply and demand imbalance amount is started, the load restriction amount or the power supply restriction amount is determined according to the obtained initial or additional supply and demand imbalance amount, After performing the generator or load shutoff, if the measured voltage becomes a preset condition when the calculation for estimating the supply / demand imbalance amount is performed again, the calculation for estimating the supply / demand imbalance amount Is to lock. According to this means, the correction control calculation is locked while a transient voltage increase after the load is limited, so that the power consumption of the load increases with the voltage increase, and the control amount is excessively calculated. Even in this case, excessive control can be prevented and a highly reliable device can be obtained.
[0023]
  Claim 10The invention of claim 1 to claim 1Claim 3In any one of the power system frequency stabilizers described above, adjustment is made so as to select preset inertia constants of a plurality of generators based on a preset condition when estimating the supply and demand imbalance amount Is to do. According to this measure, the inertia constant of the equivalent generator model used to estimate the supply and demand imbalance amount is automatically adjusted using the magnitude of the frequency change rate, so the control amount corresponding to the actual phenomenon is calculated. it can. In particular, when the frequency smoothing processing means of the invention of claim 5 and the control calculation start determination means of the invention of claim 7 are combined, the initial control amount is high when the frequency change rate is high and the urgency of control is high. Since it is controlled a lot, and a time margin is created after control, the amount of data used for smoothing processing can be increased and the additional control amount can be calculated with high accuracy. Therefore, the device should be highly operational and calculate the control amount with high accuracy. Can do.
[0024]
  Claim 11The invention of claim 1 to claim 1Claim 3In any one of the power system frequency stabilizers described above, the inertia constant of the generator is increased or decreased based on the magnitude of the frequency change rate when the supply / demand imbalance amount is estimated. . According to this measure, the inertia constant of the equivalent generator model used to estimate the supply and demand imbalance amount is automatically adjusted using the magnitude of the frequency change rate, so the control amount corresponding to the actual phenomenon is calculated. it can. In particular,Claim 4Frequency smoothing processing means of the inventionClaim 6When combined with the control calculation start determination means of the invention of the present invention, when the frequency change rate with high urgency of the control is large, the initial control amount is controlled to be large, and a time margin is created after the control. Since the additional control amount can be calculated with high accuracy by increasing the number of data used for the above, it is possible to provide a device that has high operability and calculates the control amount with high accuracy.
[0025]
  ContractClaim 12The invention of claim1 descriptionIn a power system frequency stabilization device, a predetermined calculation is performed based on various amounts of electricity when the frequency is stable and various amounts of electricity when the frequency fluctuates, and the power limit amount or load limit amount is corrected. It is what you do. According to this means, the control amount is automatically corrected using the various measured electric quantities, so that it is possible to calculate the control amount in accordance with the actual phenomenon and to obtain a highly operable device.
[0026]
  Claim 13The invention of claim 1 to claim 1Claim 3In any one of the power system frequency stabilization apparatuses described above, a load feeder for limiting a load or a generator for limiting a power source is selected based on a predetermined condition set in advance. According to this means, it is possible to automatically select a load feeder or a generator to be disconnected from the system, so that an apparatus with excellent operability can be obtained.
[0027]
  Claim 14The invention of claim 1 to claim 1Claim 3In any of the power system frequency stabilizers described above, the switching information and current, voltage, and validity of the circuit breaker of the interconnection line between the local system to which the monitored power station belongs and the other main system of the power system Collects various amounts of electricity, including electric power, etc., and generator disassembly information indicating whether the generators in the local system are in operation, as well as the rated output and inertia of the generators in the local system that are set and stored in advance. The inertia constant of the equivalent generator model when the local system side viewed from the interconnection line is represented by one equivalent generator model using various generator information including constants and the collected parallel information of the generator. A system state estimation unit is provided which is calculated by a predetermined calculation and uses the calculated inertia constant as a generator inertia constant used when estimating the supply and demand imbalance. According to this means, since the inertia constant of the equivalent generator model used when estimating the supply and demand imbalance amount can be accurately calculated, a highly accurate device can be obtained.
[0028]
  Claim 15The invention ofClaims 1 to 3In any one of the power system frequency stabilizers described above, when a part of the frequency stabilizers in the separated system is inoperable due to a failure or the like, the frequency stabilizer that operates normally is failed. The control is performed in consideration of the load limit or power source limit to be implemented by the control apparatus. According to this means, even when there are an unspecified number of erroneous and non-operating frequency stabilization devices, the control amount including the insufficient control amount can be calculated in the normal operation device. Can provide.
[0029]
  Claim 16The invention ofClaims 1 to 3In any one of the power system frequency stabilization apparatuses described, this apparatus is installed only at a part of electric power stations in the power system to which the monitored electric power station belongs. According to this means, by installing this apparatus only at some electric stations in the power system, it is possible to suppress the frequency drop or increase of the local system and control it to the reference frequency, thereby simplifying the system. In addition, even if there are unmonitored loads, uncontrollable loads, or power transmission losses, additional control amounts can be calculated, including control amounts for these, providing a highly reliable and operable frequency stabilization device. it can.
[0030]
  Claim 17The invention ofClaims 1 to 3In any of the power system frequency stabilization apparatuses described, the control target frequency is reviewed using the obtained frequency change rate. According to this means, since the target control frequency is selected based on the frequency change rate, when the frequency reduction rate is large and the urgency of the control is high, a large amount of control is calculated, and the frequency suppression effect is enhanced. Further, when the frequency reduction rate is small and the urgency of the stabilization control is low, the control amount is calculated to be small, and the control is performed to the reference frequency by controlling the increase in the output of the generator, so that the power failure period can be minimized.
[0031]
  Claim 18The invention ofClaim 1In the power system frequency stabilization device described above, using the coefficient calculated from the active power of the load feeder or generator before and after implementing the initial or additional load limit or power limit at the steady state before the occurrence of the accident, The amount of change in various electric quantities such as the calculated frequency change rate and the measured frequency are corrected. According to this means, since the frequency change rate used when estimating the supply / demand imbalance amount is automatically corrected using a coefficient representing the load increase / decrease characteristic, even when the load amount increases due to the voltage characteristic of the load. Since the additional control amount can be calculated with high accuracy, it is possible to provide a power system frequency stabilization device with high estimation accuracy.
[0032]
  Claim 19The invention ofClaim 1In the frequency stabilization device for the power system described, the frequency change rate calculated using the coefficients calculated from the voltage at steady state before the occurrence of the accident and before and after the initial or additional load limit or power limit The amount of change in various electric quantities and the measured frequency are corrected. According to this means, since the frequency change rate used when estimating the supply / demand imbalance amount is automatically corrected using the coefficient representing the voltage fluctuation characteristic, the influence of the voltage fluctuation can be removed and the additional control amount can be accurately obtained. Since it can be calculated, it is possible to provide a power system frequency stabilization device with high estimation accuracy.
[0033]
  Claim 20The invention ofClaim 2 or claim 3In the frequency stabilization apparatus for a power system described above, an inertia constant of a generator in a system to which a monitored electric station belongs is estimated. According to this means, the inertia constant of the equivalent generator model when the generator in the system to which the monitored electric plant belongs is represented by only one piece of information that can be measured or collected only at the end of the monitored electric plant. Can be estimated.
[0034]
  Claim 21The invention ofClaim 1In the power system frequency stabilization device described above, the control amount calculation unit of the power system frequency stabilization device described above is in a steady state before the occurrence of an accident and before or after the initial or additional load limitation or power source limitation. The calculated control amount is corrected using a coefficient calculated from the active power of the load feeder or generator. According to this means, since the control amount is automatically corrected using a coefficient representing the load increase / decrease characteristic, the additional control amount can be accurately calculated even when the load amount changes due to the voltage characteristic of the load. It is possible to provide a power system frequency stabilization device with high estimation accuracy in consideration of voltage characteristics.
[0035]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0036]
FIG. 1 is an overall configuration diagram of a power system frequency stabilization apparatus according to the present invention.
[0037]
In FIG. 1, the main system 101 and the local system 103 of the power system 100 are connected by the interconnection line 102, and the voltage, current, active power, system frequency, etc. for each electric station from the transmission line 104 connected to the monitoring target. Are included in the frequency stabilizing device 120.
[0038]
The frequency stabilization device 120 includes a system state measurement unit 1, a frequency calculation unit 2, a control amount calculation unit 3, a control unit 4, and a system state storage unit 5, and is based on various electric quantities input from the local system 103. Thus, the control amount obtained by the control unit 4 is transmitted from the stabilization control line 105 to the local system 103.
[0039]
FIG. 2 is a configuration diagram of a power system frequency stabilization device showing a specific example of the power system frequency stabilization device shown in FIG. 1, and the local system 103 is connected by a main system 101 and a connection line 102. Connected to an electrical station 107 via a circuit breaker 106 by a power transmission line 108. In addition, a plurality of frequency stabilization devices 120 for connecting the measuring instrument 111 to the electric station 107 in the vicinity of the generator 109 or the load 110 are provided.
[0040]
  FIG. 3 shows the first embodiment of the present invention.Show formIt is a block diagram of a frequency stabilization apparatus.
[0041]
In FIG. 3, the system state measurement unit 1 measures various amounts of electricity including the current, voltage, active power of the load feeder or generator, the frequency of the system, and the like at every moment to be monitored. The frequency calculation unit 2 includes frequency calculation means 21 that calculates changes in various electric quantities such as a frequency change rate by a predetermined calculation using various electric quantities including the frequency.
[0042]
The control amount calculation unit 3 uses the calculated frequency change rate and the inertia constant of the generator in the local system to which the monitored electric station belongs to calculate the supply and demand imbalance amount of the local system to which the monitored electric station belongs. It comprises main control calculation means 31 that estimates by a predetermined calculation and determines a load limit amount or a power source limit amount according to the estimated supply and demand imbalance amount.
[0043]
The control unit 4 shuts off the load or the generator according to the load limit amount or the power source limit amount. The system state storage unit 5 stores various electric quantities measured by the system state measurement unit 1, the calculation result of the frequency calculation unit 2, and the calculation result of the control amount calculation unit 3, so that they can be called up as necessary. It has become.
[0044]
Here, when the circuit breaker 106 of the interconnection line 102 shown in FIG. 2 is opened, a supply / demand imbalance corresponding to the interconnection line power flow occurs in the local system 103, and the frequency in the local system 103 decreases or increases. .
[0045]
First, in the system state measuring unit 1, various electric quantities including the voltage V, current I, active power P, and frequency f of the system are measured momentarily via the measuring instrument 111 installed in the monitoring target electric station 107. These are passed to the frequency calculation unit 2 and stored in the system state storage unit 5.
[0046]
The active power P or the frequency f may be obtained by calculation using an existing calculation method using the measured voltage V or current I.
[0047]
The frequency calculation means 21 of the frequency calculation unit 2 uses the measured frequency f or the frequency f obtained by calculation to calculate the change at a certain time interval, that is, the frequency change rate df / dt by calculation, and the result is calculated. While being transferred to the control amount calculation unit 3, it is stored in the system state storage unit 5. For example, the frequency change rate is continuously calculated with dt = 10 ms.
[0048]
The control amount calculation unit 3 uses the frequency change rate df / dt calculated by the frequency calculation unit 2 and an inertia constant M of a generator (described later) in the local system to which the monitoring target electric plant belongs to determine the monitoring target electric station. The supply / demand imbalance amount ΔP of the local system to which the unit belongs is estimated by a predetermined calculation, and the load restriction amount or the power supply restriction amount is determined according to the estimated supply / demand imbalance amount ΔP.
[0049]
Specifically, when there are a plurality of monitoring target electric stations in the local system 103 as shown in FIG. 2, the local system 103 to which a certain monitoring target electric station belongs is shown in FIG. The system 103 is considered as an equivalent system model of one load and one generator. In this equivalent system model, using the frequency change rate df / dt calculated in the frequency calculation unit 2 and the inertia constant M of the equivalent generator, the following equation (1.1) is used to calculate the supply and demand imbalance in the local system 103. The quantity ΔP is determined. In addition, all electric quantities are unified to PU (percent unit).
[0050]
ΔP = Δf · M (1.1)
[0051]
Here, Δf is the frequency change rate df / dt obtained by the frequency calculation unit 2, M is the inertia constant of the equivalent generator, and when the local system 103 is equivalently contracted to an equivalent system model of one load and one generator. The constant is a value obtained and set in advance, and is a value obtained by weighted averaging with the rated output of each generator in the local system 103.
[0052]
The equation (1.1) can be derived from the equation of motion of the generator as follows.
[0053]
Considering the local system to which the monitored electrical plant belongs as an equivalent system model of one load and one generator, the machine input of the generator is P_m, P is the electrical output_eIf the inertial constant of the equivalent generator is M, equation (1.2) is established from the equation of motion of the generator.
[0054]
[Expression 1]

[0055]
Where the electrical output P_e= Load power consumption P_L(P_m-P_e) = Supply and demand imbalance amount ΔP in the local system. Therefore, the supply and demand imbalance amount ΔP can be obtained by the equation (1.1).
[0056]
Note that the frequency drop or rise occurs due to an imbalance between the power consumption and the power generation amount in the system, that is, the supply and demand imbalance. If the control is performed, the supply and demand imbalance in the local system 103 is eliminated, the frequency drop or rise is suppressed, and control (stabilization) is performed to the steady-state frequency before the frequency drop or rise occurs. it can.
[0057]
As described above, all the electric quantities used in the equation (1.1) are PU values, and the supply and demand imbalance amount ΔP estimated in the equation (1.1) is the machine input P of the equivalent generator model._mP is 1.0 [PU]_mAnd P_eIs the difference. For example, the supply / demand imbalance amount ΔP when the frequency change rate df / dt is 0.01 and the inertia constant M of the equivalent generator model is 5.0 [seconds] with the frequency lowering side plus is (1.1) From the formula, 0.01 x 5.0 = 0.05 [PU], and machine input P_m= 5% of 1.0 [PU] is the supply and demand imbalance amount ΔP in the equivalent system model.
[0058]
Therefore, the value obtained by multiplying 0.05 [PU] of the supply / demand unbalance amount ΔP by the total value (total power generation amount) of all the generators in the local system at the normal time is the actual supply / demand unbalance in the local system. As a result, if the load of 5% of the total power generation amount of the generator in the local system is shut off, the supply and demand imbalance is eliminated and the frequency reduction can be prevented.
[0059]
A stabilization control amount (load limit amount or power supply limit amount) for each frequency stabilizing device is determined from the estimated supply and demand imbalance amount ΔP as follows.
[0060]
The supply and demand imbalance amount ΔP is estimated for each frequency stabilization device installed at each electric station to be monitored, and the estimated supply and demand imbalance amount ΔP is measured at each electric station and stored in the system state storage unit 5. Called the active power P at the stationary time, and based on the active power P at the stationary time, the estimated proportion of ΔP is the control amount P_CUTIt is determined as (load limit amount or power source limit amount).
[0061]
For example, the frequency reduction side will be described as an example. The estimated supply and demand imbalance amount ΔP is 0.05 [PU], and the active power P in the steady state of all loads connected to the electric station_LTIs 2.0 [PU], 5% of 2.0 [PU], that is, 0.1 [PU] is set as the load limit amount.
[0062]
The control amount P determined in this way_CUTIs transferred to the control unit 4, the control unit 4 controls the control amount P obtained by the control amount calculation unit 3._CUTDepending on the load limit amount or power source limit amount, the load or generator connected to the monitored electric station is disconnected from the system to prevent the frequency from falling or rising.
[0063]
As described above, according to the first embodiment of the present invention, supply-demand balance in the entire system to which the monitoring target electric power plant belongs only by the information of the monitoring target electric power station and only information that can be measured or collected. Since the balance amount can be estimated and the control amount can be calculated based on the estimated supply and demand imbalance amount, there is no need to collect information measured at various locations in the power system and a wide-area information transmission network is not required. In addition, since monitoring and control can be performed individually for each electric station to be monitored, it is possible to provide a power system frequency stabilization device with a simple device configuration and high operability.
[0064]
  Next, the second embodiment of the present inventionForm of power systemThe operation of each component and means of the frequency stabilizing device will be described with reference to FIGS. 1, 2, 4, and 5. FIG.
[0065]
FIG. 1 is a configuration diagram of a power system frequency stabilization device according to the present invention, FIG. 2 is a configuration diagram of a power system frequency stabilization device showing a specific example of FIG. 1, and FIG. 5 is a second configuration of the present invention. It is a block diagram of the frequency stabilization apparatus of the electric power system which shows this embodiment.
[0066]
In FIG. 5, the system state measurement unit 1 measures various amounts of electricity including the current, voltage, load feeder or generator active power, frequency of the system, etc. at the end of the monitoring target. The frequency calculation unit 2 includes frequency calculation means 21 that calculates changes in various electric quantities such as a frequency change rate by a predetermined calculation using various electric quantities including the frequency.
[0067]
The control amount calculation unit 3 includes an initial control calculation unit 31 ′ and a correction control calculation unit 32. The initial control calculation means 31 ′ uses the method described in the first embodiment to calculate the monitoring target by using the calculated frequency change rate and the inertia constant of the generator in the local system to which the monitoring target electric station belongs. The supply / demand imbalance amount of the local system to which the electric power station belongs is estimated by a predetermined calculation, and the initial load limit amount or power supply limit amount is calculated according to the estimated supply / demand imbalance amount. The correction control calculation means 32 is the initial, or before and after the additional load restriction or power supply restriction, the frequency change rate, the coefficient calculated from the active power of the load feeder or generator, and the controlled load restriction. Estimate the supply and demand imbalance amount of the local system to which the monitored electric power station belongs after initial or additional load limitation or power limitation by using a predetermined amount by using a predetermined amount or the power source limitation amount. The additional load limit amount or power supply limit amount is determined according to the supply / demand imbalance amount. The control unit 4 shuts off the load or the generator according to the load limit amount or the power source limit amount.
[0068]
The second embodiment of the present invention is characterized in that the supply and demand imbalance amount estimation and the additional load limitation or power source limitation are performed a plurality of times in accordance with preset conditions.
[0069]
Next, the flow of processing according to the second embodiment of the present invention will be described with reference to FIGS. In addition, since the effect | action of the system state measurement part 1, the frequency calculating part 2, and the system state memory | storage part 5 is the same as that of 1st Embodiment, description is abbreviate | omitted.
[0070]
First, in the control amount calculation unit 3, the initial control calculation unit 31 ′ uses the frequency change rate df / dt calculated by the frequency calculation unit 2 and the inertia constant M of the generator in the local system to which the monitored electric station belongs. Thus, by the method described in the first embodiment, the supply and demand imbalance amount ΔP of the local system to which the monitored electric station belongs_C1Is estimated by a predetermined calculation, and the estimated supply and demand imbalance amount ΔP_C1The initial load limit amount or power source limit amount is determined according to the above.
[0071]
Next, the correction control calculation means 32 uses the frequency change rate df / dt and the controlled load limit amount or power source limit amount before and after the initial or additional load limit or power source limit, respectively. Supply / demand unbalance amount ΔP of the local power system to which the monitored power plant belongs after additional load limitation or power limitation_C2Is estimated by a predetermined calculation, and the estimated supply-demand imbalance amount ΔP_C2The additional load limit amount or power supply limit amount is determined according to.
[0072]
Hereinafter, the initial control calculation means 31 'and the correction control calculation means 32 will be described in detail.
[0073]
First, in the initial control calculation means 31 ', the initial control amount P of the same ratio is uniformly obtained at each electric station immediately after the occurrence of the accident._CUT1Is controlled to suppress the frequency decrease rate or the increase rate, thereby securing a time margin for executing the correction control calculation. Therefore, the initial control amount P_CUT1May be a fixed value set in advance, but there is a possibility of over-control depending on supply and demand imbalance._CUT1Is calculated.
[0074]
Using the frequency change rate df / dt calculated by the frequency calculation unit 2 and the inertia constant M of the generator in the local system to which the monitored electric station belongs, the supply / demand imbalance amount ΔP of the local system to which the monitored electric station belongs_C1Is estimated by a predetermined calculation, and the estimated supply-demand imbalance amount ΔP_C1The load limit amount or power supply limit amount is determined according to the above.
[0075]
ΔP_C1= Δf · M (2.1)
[0076]
Specifically, the local system to which the monitored electric station belongs is considered as an equivalent system model of one load and one generator as shown in FIG. 4, and is equivalent to the frequency change rate df / dt calculated by the frequency calculation unit 2. Using the inertia constant M of the generator, for each frequency stabilizer installed at each electric power station, the supply and demand imbalance amount ΔP in the local system is independently calculated from equation (2.1)._C1[%] Is estimated. Since the frequency measured at each electric station end fluctuates in almost the same manner in the local system, ΔP calculated by each device_C1[%] Is almost the same amount.
[0077]
Note that the initial control is intended to ensure a time margin for executing the correction control calculation, and the inertia constant M varies depending on the operating state of the generator. Therefore, M is a value smaller than the true value. It is desirable to set to. For example, if the true value of the inertia constant M of the equivalent generator when the local system is reduced to the equivalent model of one load and one generator (M is a weighted average value of the rated output) is 10 [seconds], Set to a small value such as 5 or 6 [seconds].
[0078]
Next, the initial control amount (load limit amount or power source limit amount) P to be controlled at each electric station end_CUT1Is the estimated supply-demand imbalance amount ΔP_C1And the total load or power generation amount (= P_LOT) To calculate from equation (2.2).
[0079]
P_CUT1= P_LOT・ ΔP_C1  .... (2.2)
[0080]
Here, Δf is the frequency change rate df / dt, M obtained by the frequency calculation unit 2 is the inertia constant of the equivalent generator, and the constant when the local system is equivalently reduced to the equivalent system model of one load and one generator. Is a value obtained and set in advance, and is a value obtained by weighted averaging with the rated output of each generator in the local system. P_LOTIs the total load amount or total power generation amount in the electric power plant measured in the steady state before the accident occurred.
[0081]
Equation (2.1) can be derived from the equation of motion of the generator as follows. Considering the local system to which the monitored electric station belongs as an equivalent system model of one load and one generator, the machine input of the generator is Pm, the electric output is Pe (= load power consumption P_L), Where M is the inertial constant of the equivalent generator, equation (1.2) is established from the equation of motion of the generator.
[0082]
For equation (1.2), frequency change rate df / dt = Δf, supply / demand imbalance before initial control (Pm−Pe) = ΔP₁Then, ΔP_C1[%] Can be obtained by equation (2.1).
[0083]
Supply and demand imbalance amount ΔP estimated by equation (2.1)_C1For example, when the frequency lowering side is described as an example, the supply amount (power generation amount) is insufficient when the electrical output Pe (= load power consumption PL) of the equivalent generator model is 1.0. Demand / supply imbalance amount ΔP when frequency change rate df / dt (dt = 10 ms) is 0.01 and inertial constant M of the equivalent generator model is 5.0, with the frequency decreasing side being positive_C1Is 0.01 × 5.0 = 0.05 from the equation (2.1), and the total power generation amount is 5% lower than the total load amount in the local system. Therefore, if the load of 5 [%] of the total load amount in the local system is cut off, the supply and demand imbalance is eliminated and the frequency reduction can be suppressed.
[0084]
Next, the estimated supply and demand imbalance amount ΔP_C1To initial control amount P for each electrical station end (for each frequency stabilizer)_CUT1In order to obtain (load limit amount or power source limit amount), specifically, for example, the frequency lowering side will be described. For example, P in the electric stations A1, A2, A3 in the local system_L1= 2000 [MW], P_L2= 1000 [MW], P_L3= 500 [MW] load (total load P at steady state)_LOT) And supply and demand imbalance amount ΔP estimated at the end of each electric station._C1Is estimated to be 5 [%], the control amount at each electric station is 5 [%] of 2000 [MW] for the electric station A1, that is, 100 [MW], and the electric power A2 is 1000 [%]. 5 [%] of MW], that is, 50 [MW], and the electric power station A3 sets 5 [%] of 500 [MW], that is, 25 [MW], as an initial limit amount controlled at the electric station. The frequency in the separation system fluctuates in almost the same manner, and ΔPC1 estimated at each electric station end is almost the same amount. Therefore, even in a distributed system configuration, initial control of α [%] is uniformly performed at each electric station end. Can be implemented. The control amount obtained in this way is passed to the control unit 4 and stored in the system state storage unit 5.
[0085]
In the control unit 4, the initial control amount P obtained by the control amount calculation unit 3 is used._CUT1Depending on the initial load limit amount or power source limit amount, the load or generator connected to the monitored electric power station is disconnected from the system to prevent frequency reduction or increase.
[0086]
After the initial control is performed, the correction control calculation unit 32 checks whether the frequency after the initial control is continuously decreased or increased as before the initial control is performed, and continues to decrease or increase as before the control is performed. Frequency change rate df / dt (hereinafter referred to as Δf) before the initial control (initial load limitation or power source limitation) is performed._bfAnd df / dt (hereinafter referred to as Δf)_afAnd the initial control amount P_CUT1And load increase / decrease characteristic coefficient a calculated from the active power of the load feeder or generator_bfAnd a_afUsing (2.3), the supply and demand imbalance amount ΔP in the local system after the initial control is performed in consideration of the voltage characteristics and frequency characteristics of the load._C2(= Shortage in initial control) is estimated. If the load increase / decrease characteristics are not considered, the coefficient a_bfAnd coefficient a_afMay be set to 1.0, and the frequency change rate Δf before the initial control is performed._bfSupply and demand imbalance before initial control_C1Is called and used in the system state storage unit 5.
[0087]
[Expression 2]

[0088]
Here, Δf is the frequency change rate df / dt obtained by the frequency calculation unit 2, and the subscript bf in the equation indicates a value before the execution of control, and af indicates a value after the execution of control. ΔP_C1Is the supply-demand imbalance amount ΔP before the initial control is performed in the first additional control calculation._C1In the second and subsequent additional control calculations, the initial control amount (= ΔP_C1) And additional control amount (= ΔP)_C2).
[0089]
Additional control amount (additional load limit or power supply limit) P to be controlled at each electric power station itself P_CUT2Is the supply-demand imbalance amount ΔP_C2[%] And the total load or power generation amount (= P_LOT) To calculate with the formula (2.4).
[0090]
P_CUT2= P_LOT・ ΔP_C2  .... (2.4)
[0091]
Estimated supply and demand imbalance amount ΔP_C2To additional control amount P at each electrical station end (for each frequency stabilization device)_CUT2Specifically, for example, the frequency lowering side will be described as an example. The electric stations A1, A2, and A3 in the local system are connected to P._L1= 2000 [MW], P_L2= 1000 [MW], P_L3= 500 [MW] load (total load P at steady state)_LOT), The supply and demand imbalance amount ΔP estimated at the end of each electric station_C2Is estimated to be 2 [%], the additional limit amount at each electric power station is 2 [%] of 2000 [MW] for the electric power station A1, that is, 40 [MW], and the electric power station A2 is , 1000 [MW] 2 [%], that is, 20 [MW], and the electric station A3 controls 2 [%] of 500 [MW], that is, 10 [MW], at the electric station. Amount. The additional control amount obtained in this way is passed to the control unit 4 and stored in the system state storage unit 5.
[0092]
In the control unit 4, the additional control amount P obtained by the control amount calculation unit 3._CUT2Depending on the (additional load limit amount or power supply limit amount), the load or generator connected to the monitored electric station is disconnected from the system to prevent the frequency from being lowered or increased.
[0093]
Normally, the supply-demand imbalance amount ΔP obtained from equation (2.3)_C2If the same amount of control is performed, the supply and demand imbalance in the local system can be eliminated, and the frequency drop or rise can be suppressed, and the frequency can be controlled (stabilized) to the normal frequency before the frequency drop or rise occurs. However, when the system state changes such as increase / decrease in demand or change in load characteristics, it is conceivable that one additional control results in insufficient control.
[0094]
For this reason, after the additional control, the frequency decrease or increase is confirmed, and if the decrease or increase continues as before the control, the following processing is performed.
[0095]
Specifically, the frequency change rate Δf before performing the additional control stored in the system state storage unit 5_bfAnd frequency change rate Δf after additional control_afAnd total value P of initial control amount and additional control amount stored in system state storage unit 5_C1Using the formula (2.3), the supply and demand imbalance amount ΔP after the additional control_C2The additional control amount is stored in the system state storage unit 5 together with the additional control. The additional control is repeated until the frequency decrease or increase is stopped.
[0096]
The following formula (2.3) and load increase / decrease characteristic coefficient a_bf, A_afWill be described.
[0097]
Similar to the initial control calculation, the local system to which the monitored electric station belongs is considered as an equivalent system model of one load and one generator as shown in FIG. 4, and the mechanical input of the generator is Pm, the electrical output is Pe, and the equivalent generator If the inertia constant of is M, the equation (1.2) is established from the equation of motion of the generator. Hereinafter, the amount indicating the time change is indicated by (t).
[0098]
The frequency fluctuation before the initial control can be expressed by the equation (2.5) from the equation (1.2), where t- is the time before the control. Δf is a frequency change rate df / dt.
[0099]
[Equation 3]

[0100]
However, in practice, when the power supply amount decreases due to system separation, the voltage decreases, and accordingly, the load amount (= Pe (t−)) immediately after system separation decreases. Therefore, the coefficient a representing the increase / decrease characteristic of the load in equation (2.5)_bfUsing (), an estimation formula that takes into account the decrease in load is derived as shown in (2.6).
[0101]
[Expression 4]

[0102]
On the other hand, the frequency fluctuation after the initial control is such that the load or the generator is uniformly α [%] (= ΔP) at each electric station in the initial control._C1) Shut off. Therefore, the control of α [%] is also performed for the total load amount or the total power generation amount of the local system. Therefore, when the time after the control is performed is t +, it can be expressed by the equation (2.7). it can. Equations (2.5) and (2.7) are approximate equations when it is assumed that there is no load characteristic (load voltage characteristic, frequency characteristic).
[0103]
[Equation 5]

[0104]
However, in practice, after the initial control, the load amount after the first-stage control (= Pe (t +) − ΔP) as the voltage increases due to stabilization control such as load limitation._C1) Is increasing. Therefore, the coefficient a representing the increase / decrease characteristic of the load in the equation (2.7)_afUsing (), an estimation formula that takes into account the increase in load is derived as (2.8).
[0105]
[Formula 6]

[0106]
Assuming that the time difference between the times t− and t + is short, and assuming that Pm (t −) = Pm (t +) and Pe (t −) = Pe (t +), the equation (2.8) −the equation (2.5) Than,
[0107]
[Expression 7]

[0108]
Therefore,
[0109]
[Equation 8]

[0110]
Substituting equation (2.10) into equation (2.8), power consumption P_LDemand-supply imbalance after initial restriction ΔP_C2{−Pm (t +) + a_af・ (Pe (t +) − ΔP_C1)}, ΔP_C2[%] Can be obtained by equation (2.11).
[0111]
[Equation 9]

[0112]
Here, the load amount Pe (t +) after the initial load limit is the total load amount P at the normal time in the electric station._LOTTo initial control amount P_CUT1Therefore, Pe (+) = P_L(+) = (P_L0-P_CUT1) = (1−ΔP_C1) ΔP_C2[%] Can be obtained by equation (2.12) (= (2.3) equation). In other words, if the supply and demand imbalance amount is estimated using equation (2.3), ΔP taking into account the voltage and frequency characteristics of the load._C2Can be requested.
[0113]
[Expression 10]

[0114]
The load increase / decrease characteristic coefficient a_bf, A_afΔP without considering_C2The estimation formula of (2) is the formula (2.13).
[0115]
[Expression 11]

[0116]
Next, load increase / decrease characteristic coefficient a_bf, A_afIn consideration of calculating from the amount of electricity that can be measured at each monitored power station, the total load amount or total power generation amount (= P_L) And initial control amount P_CUT1Calculate using.
[0117]
FIG. 6 shows the load increase / decrease characteristic coefficient a._bf, A_afSpecifically, the load increase / decrease characteristic coefficient a from moment (2.14) immediately after system separation._bfIs calculated, and the average value is obtained from equation (2.15). Also, after the initial control, the load increase / decrease characteristic coefficient a is momentarily calculated from the formula (2.16)._afIs calculated, and the average value is obtained from equation (2.17). Sought a_bf, A_afIs used in the equation (2.3) for estimating supply and demand imbalance. For example, according to the period of voltage fluctuation, the average value of the same time (section) as the fluctuation period is calculated as the load increase / decrease characteristic coefficient a._bfOr a_afUsed as Moreover, using the measured voltage, immediately after system separation, the steady-state voltage V measured before the frequency drop or rise occurs.₀The load increase / decrease characteristic coefficient a_bfIs obtained from time to time, and the average value of the interval is used in equation (2.3). In addition, after the initial control or after the additional control, the steady-state voltage V₀Or the voltage V just before the initial control_C1bfThe load increase / decrease characteristic coefficient a_afIs obtained from time to time, and the average value of the interval is used in equation (2.3). Note that n is the total number of data.
[0118]
[Expression 12]

[0119]
As described above, according to the second embodiment of the present invention, it is possible to estimate the supply and demand imbalance amount in the system to which the monitored electric power plant belongs only by the total value of the cut-off control amount and the frequency change rate. There is no need to set parameters for calculation, and the control amount is calculated from the estimated supply and demand imbalance. it can. Furthermore, additional control is repeatedly performed, so that insufficient control can be prevented, and supply / demand imbalance amounts are estimated based only on information that can be measured or collected only at the monitored electrical station end. Based on the estimated supply / demand imbalance amounts Control amount can be calculated, so there is no need to collect information measured at various places in the power system, no need for a wide-area information transmission network, the system scale can be reduced, and each monitored electric station can be monitored individually Therefore, it is possible to provide a power system frequency stabilization device that can perform control, has a simple device configuration, high controllability, and excellent operability and maintainability.
[0120]
In addition, since the supply / demand imbalance amount can be estimated in consideration of the load increase / decrease characteristic coefficient obtained from the effective power of the electric station, the estimation accuracy can be improved.
[0121]
Furthermore, in the second embodiment of the present invention, a frequency stabilization device that obtains the load increase / decrease characteristic coefficient from the measured voltage instead of the active power of the electric station and estimates the supply and demand imbalance in the local system Will be described.
[0122]
In the correction control calculation means 32 of FIG. 5, when estimating the supply and demand imbalance amount of the system to which the monitored electric power station belongs after initial or additional load limitation or power source limitation, the initial or additional load limitation or The frequency change rate before and after the power supply restriction and the coefficient calculated from the measured voltage and the controlled load restriction amount or power supply restriction amount are used.
[0123]
Specifically, in order to remove the influence caused by the voltage increase that occurs when the initial load restriction is performed, the supply and demand imbalance amount ΔP in the local system after the initial control is performed._C2Is estimated from equation (2.18).
[0124]
[Formula 13]

[0125]
Where a_bfv, A_afvIs a voltage fluctuation coefficient that represents a decrease or increase in voltage, and is an estimation formula for the supply and demand imbalance amount in consideration of the voltage fluctuation. A_bfv, A_afvIs obtained as follows.
[0126]
Voltage fluctuation coefficient a_bfv, A_afvIn consideration of calculating from the amount of electricity that can be measured at the end of the monitored electric station, the calculation method of the voltage V at the steady state before the occurrence of the accident at each electric station₀The voltage Vn and the frequency deviation Δfn measured every moment are calculated.
[0127]
Specifically, the voltage fluctuation coefficient a is momentarily calculated from the equation (2.19) or (2.20)._bfvnIs calculated, and the average value is obtained from equation (2.21). In addition, the voltage variation coefficient a is momentarily calculated from the equation (2.22) or (2.23)._afvnIs calculated, and the average value is obtained from the equation (2.24). The obtained voltage fluctuation coefficient a_bfvn, A_afvIs used in the equation (2.3) of the estimation calculation of supply and demand imbalance.
[0128]
For example, the voltage variation coefficient a_bfvUses the average value of the same time (section) as the oscillation period in accordance with the voltage oscillation period after system separation. Voltage fluctuation coefficient a_afvUses the average value of the same time (section) as the oscillation period in accordance with the voltage oscillation period after the initial control. Or the voltage fluctuation coefficient a_bfvIs the voltage Vn measured every moment, the voltage V in the steady state₀The voltage coefficient of variation a_bfvnAnd the average value of the section is obtained by equation (2.21). Voltage fluctuation coefficient a_afvIs the steady-state voltage V₀Or the voltage V just before the initial control_C1bfThe voltage variation coefficient a_afvnAnd the average value of the section is obtained by equation (2.24).
[0129]
[Expression 14]

[0130]
Here, n is the total number of data. In the equations (2.22) and (2.23), V₀Instead of the voltage V immediately before the initial control_C1bfMay be used. K_VAIs a constant that sets the ratio of the voltage characteristics of the load. K_VBIs a preset coefficient. α is a preset voltage characteristic index of the load. K_fPIs a preset frequency characteristic constant [% / Hz]. Δfn is a frequency deviation [Hz] (from the reference frequency) obtained from the measured frequency.
[0131]
As described above, in the second embodiment of the present invention, the load fluctuation characteristic coefficient is calculated as the voltage fluctuation coefficient calculated from the measured voltage, thereby estimating the supply and demand imbalance amount considering the voltage fluctuation. Since it can do, estimation accuracy can be raised. Further, since the frequency smoothing process for removing the influence of the voltage fluctuation can be deleted or the data section length used for the smoothing process can be shortened, the additional control amount can be calculated in a short time.
[0132]
  Next, the third embodiment of the present inventionRelated to formThe operation of each component and means of the power system frequency stabilization device will be described with reference to FIGS. 1, 2, and 7. FIG.
[0133]
In the frequency stabilizing unit of the power system frequency stabilizing device according to the first embodiment or the second embodiment, the power system frequency stabilizing device according to the third embodiment of the present invention is provided. The configuration is characterized by having a frequency smoothing means 22 for taking an error countermeasure including a smoothing process (filtering) on a change amount of various electric quantities such as a calculated frequency change rate or a measured frequency.
[0134]
Next, the overall processing flow of the third embodiment of the present invention will be described with reference to FIGS. The operation of the system state measurement unit 1, the control amount calculation unit 3, the control unit 4, and the system state storage unit 5 and the operation of the frequency calculation unit 21 of the frequency calculation unit 2 are the same as those in the first embodiment or the second embodiment. Since it is the same as that of form, description is abbreviate | omitted.
[0135]
Here, for example, when the frequency change of the separated system after the system separation or the like occurs, the frequency may oscillate in a short cycle due to the influence of the sway of the generator in the system. In such a case, when the frequency change rate is obtained by using the measured frequency as it is, the frequency change rate changes depending on the calculated time point, and the above formula (1.1), formula (2.1), or (2. If an attempt is made to estimate the supply and demand imbalance amount ΔP in the local system using the equation (3), the estimation result may vary due to the change in the frequency change rate, that is, the influence of the frequency fluctuation. For this reason, it is necessary to eliminate or reduce the influence of frequency fluctuations.
[0136]
The frequency smoothing processing means 22 of the frequency calculation unit 2 shown in FIG. 7 performs a smoothing process on a change amount of various electric quantities such as a calculated frequency change rate and a measured frequency. Reduces the effects of shaking in short cycles or sudden changes in a very short time. For example, as a smoothing process, an average of various electric quantities such as a frequency change rate and a frequency in a certain section is obtained.
[0137]
Specifically, the interval for which the average is calculated is the data interval length T_SMPSet as time. The data section length T based on the time point when the decrease or increase occurs, using various amounts of electricity measured after the frequency decrease or increase and the calculated frequency change rate stored in the system state storage unit 5_SMPUsing the data in between, the average value of this section is obtained for each amount of electricity, and the average value is used for the calculation of the control amount of the control amount calculation unit 3.
[0138]
Since various electric quantities are measured every moment, when new data is measured, the data section is updated and the average value is continuously obtained in time series. In other words, the average of the interval in which new data is added is obtained except for the oldest data. The same operation is repeated each time new data is measured.
[0139]
Here, the data section length T used for smoothing_SMPIs set to be the same as the period of power fluctuation, for example. If the oscillation period is about 1 [second], the average value for 1 second is continuously obtained in time series. Various amounts of electricity such as frequency change rate and frequency smoothed as described above are transferred to the control amount calculation unit 3 and stored in the system state storage unit 5. The control amount calculation unit 3 calculates the control amount by using various smoothed electric quantities.
[0140]
As described above, according to the third embodiment of the present invention, the smoothing process is performed on various electric quantities used when the supply and demand imbalance amount is obtained, and therefore, when the frequency fluctuates in a long period or a short period, Even when it changes suddenly in a very short time, the supply and demand imbalance amount can be accurately estimated, and variations in estimation results can be prevented, so that a highly accurate and highly reliable power system frequency stabilization device can be provided.
[0141]
  Next, the fourth embodiment of the present inventionRelated to formThe operation of each component and means of the power system frequency stabilization device will be described with reference to FIGS. 1, 2, and 8. FIG.
[0142]
The frequency stabilization device for a power system according to the fourth embodiment of the present invention performs measurement in the frequency calculation unit 2 of the frequency stabilization device for a power system described in the first embodiment or the second embodiment. It is characterized in that it has a configuration provided with a frequency fluctuation predicting means 23 for predicting changes in various electric quantities such as a future frequency by a predetermined calculation using various electric quantities including the frequency of the selected system. .
[0143]
Next, the overall processing flow will be described with reference to FIGS. 1, 2, and 8. The operation of the system state measurement unit 1, the control amount calculation unit 3, the control unit 4, and the system state storage unit 5, and the operation of the frequency calculation unit 21 and the frequency smoothing unit 22 of the frequency calculation unit 2 are the same as those in the first embodiment. Since it is the same as that of form thru | or 3rd Embodiment, description is abbreviate | omitted.
[0144]
First, the frequency fluctuation predicting means 23 of the frequency calculation unit 2 shown in FIG. 8 uses various electric quantities such as the measured frequency of the system to predict changes in various electric quantities such as future frequencies by a predetermined calculation. For example, a frequency prediction formula is created by a method such as a least square method using various electric quantities including past frequencies stored in the system state storage unit 5 to predict a frequency value several hundred milliseconds ahead.
[0145]
The frequency prediction formula is a least square method using a past frequency as a prediction function of a primary expression or a quadratic expression as shown in the following (4.2) as shown in the following (4.1). The coefficient a by the existing method such as₀~ A₂Ask for. Then, a frequency value several hundred milliseconds ahead is predicted using the created frequency prediction formula. Since the frequency changes from moment to moment, the series of operations are repeated while updating the frequency used in the least square method, and future frequencies are predicted momentarily.
[0146]
Δf (t) = a₀+ A₁t (4.1)
Δf (t) = a₀+ A₁t + a₂t²  .... (4.2)
[0147]
Next, the frequency change rate df / dt is calculated by calculation using the frequency predicted every moment, and the calculation result is passed to the control amount calculation unit 3 and stored in the system state storage unit 5. For example, the frequency change rate is continuously calculated with dt = 10 ms. The control amount calculation unit 3 performs calculation using the predicted future frequency, its frequency change rate, and the like.
[0148]
As described above, according to the fourth embodiment of the present invention, the calculation is performed using the predicted future frequency and the frequency change rate thereof, so that the calculation result is obtained at an earlier time point than when calculating using the actual measurement value. In addition, since control can be performed at an early point, it is possible to provide a frequency stabilization device for a power system that stabilizes a decrease or increase in frequency in a short time.
[0149]
In addition, the 4th Embodiment of this invention can be implemented as shown in FIG.
[0150]
In the embodiment of FIG. 9, the frequency smoothing processing means 22 according to the third embodiment is additionally provided in FIG. 8, and the supply and demand imbalance amount is accurately obtained even when the frequency fluctuates or rapidly changes in a short time. Can be estimated.
[0151]
  Next, fifth to eighth embodiments of the present inventionImplementationThe operation of each component and means of the power system frequency stabilization device will be described in sequence with reference to FIGS. 1, 2, 10, and 12.
[0152]
As shown in FIG. 10, the power system frequency stabilization device according to the fifth embodiment of the present invention calculates the control amount of the power system frequency stabilization device described in the second embodiment shown in FIG. The unit 3 is characterized in that a control calculation start determining means 30 for switching a condition for starting a calculation for estimating the supply and demand imbalance amount using a predetermined condition set in advance is additionally provided.
[0153]
Next, the overall processing flow of the fifth embodiment of the present invention will be described with reference to FIG. 2, FIG. 10, and FIG. In addition, since the effect | action of the system state measurement part 1, the frequency calculating part 2, the control part 4, and the system state memory | storage part 5 is the same as that of any of 1st Embodiment thru | or 4th Embodiment, description is abbreviate | omitted.
[0154]
First, the control calculation start determination means 30 of the control amount calculation unit 3 in FIG. 10 starts calculation for estimating the supply and demand imbalance amount ΔP using various electric quantities such as the measured frequency and predetermined conditions set in advance. Switch conditions. For example, when performing an operation determination as to whether or not to start a calculation using the measured frequency, the operation determination threshold f_LMA plurality of frequencies are set, and the measured frequency and the operation determination threshold f_LMAnd the frequency is the threshold f_LMIf it exceeds, it is determined that the operating condition is satisfied, and calculation for estimating the supply and demand imbalance amount is started.
[0155]
The operation determination threshold f_LMIf it is set based on the frequency control system for system operation, etc., control suitable for system operation can be performed.
[0156]
Specifically, the overall processing flow will be described taking the frequency lowering side as an example. As shown in FIGS. 11 and 12, first, in the frequency calculation unit 2, measurement of various electric quantities such as frequency and frequency change rate are performed. Etc. are calculated (S11, S12).
[0157]
Subsequently, the control calculation start determination means 30 determines whether or not the frequency has decreased (S13). If the frequency has decreased, the measured frequency and the first operation determination threshold value f are determined._LM1(For example, 59.0 Hz) is compared (S14). In this comparison, the threshold value f_LM1In the following cases, the initial control calculation means 31 'is operated to calculate and control the initial control amount (S15 to S17).
[0158]
On the other hand, the threshold value f_LM1If not, the processes from (S11) to (S14) are repeated. Thereafter, the processes from (S11) to (S15) are continued after the initial control of (S16, S17), and if the frequency continues to decrease after the initial control is performed, the process proceeds to the process shown in FIG. Transition.
[0159]
First, the operation determination threshold value f is determined according to the number of times of additional control._LM2~ F_LMn(S18), the measured frequency and the selected threshold value f_LMAre compared (S19). In this comparison, the threshold value f_LMIn the following cases, the correction control calculation means 32 is operated to calculate the additional control amount and perform the first control of the additional control (S20a, 21a). On the other hand, the threshold value f_LMIf not, the processes from (S11) to (S14) in FIG. 11 and (S18m) to (S19m) in FIG. 12 are repeated.
[0160]
That is, even after the additional control of (S20a, 21a) is performed, the processing from (S11) to (S14) and (S18m) to (S21m) is performed until the frequency reduction disappears, that is, in (S13), the frequency reduction. The process is repeated until it is determined that there is none or the upper limit number (m-th) of additional control is reached.
[0161]
In addition, this embodiment has the configuration shown in FIG. 13 when used in combination with the frequency smoothing processing means 22 shown in FIG. 7 described in the third embodiment. In this case, if the frequency lowering side is described as an example, the processing flow shown in FIGS. 14 and 15 is obtained.
[0162]
First, the frequency calculation unit 2 measures various electric quantities such as frequency and calculates a frequency change rate (S11, S12). Subsequently, smoothing processing is performed by the frequency calculation means 21 on various electric quantities such as the measured frequency and the calculated frequency change rate (S12a). Next, the control amount calculation start determination means 30 determines whether or not the frequency has decreased (S13). If the frequency has decreased, the smoothed frequency and the first operation determination threshold value are determined. f_LM1Are compared (S14). In this comparison, the threshold value f_LM1In the following cases, the initial control calculation means 31 'is operated to calculate and control the initial control amount (S16, S17).
[0163]
On the other hand, the threshold value f_LM1If not, the processes from (S11) to (S14) are repeated. Thereafter, the processes from (S11) to (S15) are continued after the initial control of (S16, S17), and if the frequency continues to decrease after the initial control is performed, the process proceeds to the process shown in FIG. Transition.
[0164]
First, the operation determination threshold value f is determined according to the number of times of additional control._LM2~ F_LMn(S18), the measured frequency and the selected threshold value f_LMAre compared (S19). By this comparison, the threshold value f_LMIn the following cases, the correction control calculation means 32 is operated to calculate the additional control amount and perform the first control of the additional control (S20a, 21a). On the other hand, the threshold value f_LMIf not, the processes from (S11) to (S15) in FIG. 14 and (S18m) to (S19m) in FIG. 15 are repeated.
[0165]
That is, even after the additional control of (S20a, 21a) is performed, the processing from (S11) to (S15) and (S18m) to (S21m) is performed until the frequency reduction is eliminated, that is, in (S13), the frequency reduction is performed. The process is repeated until it is determined that there is none or the upper limit number (m-th) of additional control is reached.
[0166]
According to this embodiment, as described in the third embodiment, when the average of a certain interval is obtained as the smoothing process, the data used for the smoothing process is collected. That is, in the initial control calculation, the data interval length T after the frequency drop occurs_SMPUntil the minute time elapses, in the correction control calculation, after the initial or additional control is performed, the data section length T_SMPUntil the minute time elapses, the frequency of the system is changed to the operation determination threshold value f._LMIt is thought that it will exceed.
[0167]
In such a case, if data collection is continued with an emphasis on smoothing processing, the stabilization control is delayed, which may seriously affect the system. To prevent this, the measured frequency and the threshold f are always measured._LMAnd the frequency is the threshold f_LMIf the value exceeds, data collection for the smoothing process is interrupted. The frequency is the threshold value f after starting data collection._LMUsing the data collected until the data collection is interrupted beyond this value, an average value for each amount of electricity during this period is obtained, and the control amount is calculated in the control amount calculation unit 3 using the average value. .
[0168]
In the control calculation start determination unit 30 described above, an actual measurement value measured every moment is used for the operation determination, but the frequency fluctuation prediction unit 23 shown in FIG. 8 described in the fourth embodiment. Can be implemented in combination. According to this embodiment, since the operation determination can be performed using the predicted future frequency, the operation determination can be performed at an earlier point in time than the determination using the actual measurement value at present, and (S11) to FIG. It can replace with (S13) and can implement as a flow of a process as shown in FIG.
[0169]
As described above, according to the fifth embodiment of the present invention, since control can be performed step by step based on preset conditions, it is possible to perform control in accordance with system operation, and to provide a device with high operability. Become.
[0170]
Next, a sixth embodiment of the present invention will be described. In the sixth embodiment, the setting value of the operation determination threshold value for determining whether or not to start the calculation for estimating the supply and demand imbalance amount in the fifth embodiment shown in FIGS. For each frequency stabilization device installed at a location, the frequency stabilization device is set in accordance with the tolerance for the frequency drop or rise of the system equipment such as a load feeder or generator connected to each monitored electrical site.
[0171]
For example, as an example, a generator G that is weak against frequency rise_AThe frequency stabilizer A that monitors and controls the electrical station to which the is connected, and conversely the generator G that is strong against frequency rise_BWhen there is a frequency stabilization device B that monitors and controls the electrical station to which the is connected, the threshold value f of the frequency stabilization device A_LMiAThe threshold value f of the stabilizer B_LMiBSet to a smaller value, that is, a value close to the reference frequency, and the threshold value f of the stabilizing device B_LMiBIs the threshold value f of the stabilizer A_LMiAA larger value, that is, a value far from the reference frequency is set. Where the subscript i is the threshold f_LMIs the number of settings.
[0172]
As described above, according to the sixth embodiment of the present invention, when the frequency stabilizing device of the power system is installed in a plurality of electric stations of the power system, the operating condition is set between the plurality of frequency stabilizing devices. Since it is possible to make a mistake, unnecessary disconnection can be prevented by coordinated stabilization control.
[0173]
Next, a seventh embodiment of the present invention will be described.
[0174]
In the seventh embodiment, the control amount calculation unit 3 in the fifth embodiment shown in FIGS. 10 to 16 performs initial or additional load limitation or power source limitation using a predetermined condition set in advance. The calculation for estimating the supply and demand imbalance after the correction, that is, the correction control calculation is locked.
[0175]
Specifically, a preset correction control calculation lock time T_LKAfter the initial or additional load limit, T_LKOnly lock the calculation to estimate the supply and demand imbalance amount. For example, T_LKAssuming = 0.2 [seconds], for 0.2 seconds after the initial or additional load limitation, the estimation of the supply / demand imbalance after the initial or additional load limitation, that is, the correction control calculation is locked.
[0176]
Here, load restriction can be considered as a stabilization control means for preventing frequency reduction. For example, in systems where there is a capacitive load or system equipment such as a stuctor in the vicinity of the load disconnected from the system, Immediately after that, voltage increase due to the ferrant effect of the stacons may occur. While this voltage increase occurs, the power consumption of the load increases due to the voltage characteristics of the load. It is estimated that excessive control will be performed.
[0177]
In order to prevent this, overcorrection is prevented by locking the correction control calculation for several hundred milliseconds in order to avoid the influence of the transient voltage rise after the load limit. When combined with the smoothing processing means as in the third embodiment, the correction control calculation lock time T is set so that the influence of the voltage rise is eliminated in consideration of the balance with the data section length._LKSet.
[0178]
As described above, according to the seventh embodiment, the correction control calculation is locked while the transient voltage rise after the load limitation occurs, so that the power consumption of the load increases with the voltage rise. Even when the control amount is excessively calculated, excessive control can be prevented and a highly reliable apparatus can be obtained.
[0179]
Next, an eighth embodiment of the present invention will be described.
[0180]
In the eighth embodiment, the control amount calculation unit 3 in the fifth embodiment shown in FIGS. 10 to 16 uses the measured voltage and a preset threshold value to perform initial or additional load limiting or The calculation for estimating the supply and demand imbalance after the power supply restriction is performed, that is, the correction control calculation is locked.
[0181]
Specifically, various electric quantities such as voltage V measured every moment and a preset correction control calculation lock determination threshold V_LKThe voltage V after the initial or additional load limit is applied to the threshold V_LKWhile this is the case, the correction control calculation is locked under the condition of the following expression (1.10).
[0182]
V ≧ V_LKCorrection control calculation lock during (1.10)
[0183]
For example, threshold V_LKThe voltage during operation in a steady state is 1.00 [P. U. ], 1.00-1.20 [P. U. ] Set within a range, for example, V_LK= 1.05 [P. U. ] In advance.
[0184]
As described above, according to the eighth embodiment, the correction control calculation is locked while the transient voltage rise after the load limit is generated, so that the power consumption of the load increases with the voltage rise. Even when the control amount is excessively calculated, excessive control can be prevented and a highly reliable apparatus can be obtained.
[0185]
  Next, the ninth embodiment and the tenth implementation of the present inventionFormThe operation of each component and means of the power system frequency stabilizing device will be described with reference to FIGS. 1, 2, 17, and 18. FIG.
[0186]
In the power system frequency stabilization device according to the ninth embodiment of the present invention, the control amount calculation unit 3 of the power system frequency stabilization device according to the first embodiment or the second embodiment includes: The present invention is characterized in that it has a calculation condition setting means 310 for adjusting the inertia constant M of the equivalent generator model used when estimating the supply and demand imbalance amount.
[0187]
Next, the overall processing flow will be described with reference to FIGS. 2, 17, and 18. The operation of the system state measurement unit 1, the frequency calculation unit 2, the control unit 4, and the system state storage unit 5 is the same as that of the first embodiment to the third embodiment or the fifth embodiment. Since it is the same, description is abbreviate | omitted.
[0188]
In the calculation condition setting means 310 of the control amount calculation unit 3 shown in FIG. 17 or FIG. 18, the inertia constant M of the equivalent generator model in the aforementioned equation (1.1) used when estimating the supply / demand imbalance amount ΔP is calculated. adjust. For example, a plurality of inertia constants M are set in advance and selected according to the magnitude of the frequency change rate df / dt to be used for the calculation.
[0189]
Specifically, the relationship of the following equation (9.1) is set in advance, and compared with the relationship with equation (9.1) using the frequency change rate df / dt obtained by the frequency calculation unit 2. The largest α that satisfies the conditions_nM corresponding to (frequency change rate)_nIs determined as the inertia constant M used in the calculation.
[0190]
For example, df / dt ≧ α₁And df / dt ≧ α₂If the condition of₁<Α₂… <Α_nFrom the relationship₂M corresponding to₂Is used for calculation. As a result, the larger the frequency change rate df / dt, the greater the inertia M_nTherefore, the control amount is calculated to be larger as the frequency change rate df / dt is larger than when the inertia constant M is used as a fixed value, that is, when the frequency changes drastically and drastically. Become so.
[0191]
df / dt ≧ α₁When M₁, Df / dt ≧ α₂When M₂, ...,
df / dt ≧ α_nWhen M_n, Df / dt <α₁When M₁  .... (9.1)
Where α₁<Α₂… <Α_nAnd M₁<M₂... <M_n
[0192]
Where α_nIs a frequency change rate df / dt and is set in advance. M_nIs an inertia constant and is set in advance. N is the total number of set values.
[0193]
If the frequency smoothing processing means 22 of the third embodiment and the control calculation start determination means 30 of the fifth embodiment are used in combination, as described above, when the frequency change rate is large, that is, the frequency Since the initial control amount is controlled by a large amount when the value rapidly decreases and increases significantly, the frequency decrease degree after the initial control becomes gradual and reaches the operation determination threshold value of the correction control ( Time) until the correction control calculation is started), the number of data used for the smoothing process can be increased to increase the effect of the smoothing process, and the additional control amount can be calculated with high accuracy in the correction control calculation. .
[0194]
Thus, according to the ninth embodiment, the inertia constant of the equivalent generator model used when estimating the supply and demand imbalance amount is automatically adjusted using the magnitude of the frequency change rate. It is possible to calculate a control amount according to the above. In addition, when the frequency smoothing processing unit of the third embodiment and the control calculation start determination unit of the fifth embodiment are combined, the initial control is performed when the frequency change rate with high control urgency is large. Since the amount is controlled to a large amount, there is a time margin after control, so the number of data used for smoothing processing can be increased and the additional control amount can be calculated with high accuracy, and the operability is high and the control amount can be calculated with high accuracy. It can be.
[0195]
Next, a tenth embodiment of the present invention will be described.
[0196]
In the tenth embodiment, the calculation condition setting means 310 of FIG. 17 or 18 uses the frequency change rate df / dt to calculate the inertia constant M of the equivalent generator model used when estimating the supply and demand imbalance amount. It is to correct.
[0197]
Specifically, the calculation condition setting unit 310 uses the frequency change rate df / dt obtained by the frequency calculation unit 2 in FIG. Corrections are made as shown in equations (10.1) and (10.2).
[0198]
α = K_ADJ.DELTA.f (10.1)
M_RE= Α · M (10.2)
[0199]
Here, Δf is the frequency change rate df / dt. K_ADJIs a preset coefficient. M is a preset inertia constant, and M_REIs the corrected inertial constant.
[0200]
If the frequency smoothing processing means 22 of the third embodiment and the control calculation start determination means 30 of the fifth embodiment are used in combination, as described above, when the frequency change rate is large, that is, the frequency Since the initial control amount is controlled to be large when the value rapidly decreases or increases significantly, the degree of frequency decrease after the initial control becomes moderate. For this reason, a time margin is created until the operation judgment threshold value for correction control is reached (correction control calculation is started), so the effect of the smoothing process can be increased by increasing the number of data used for the smoothing process. In the correction control calculation, the additional control amount can be calculated with high accuracy.
[0201]
As described above, according to the tenth embodiment, the inertia constant of the equivalent generator model used when estimating the supply / demand imbalance amount is automatically adjusted using the magnitude of the frequency change rate. It is possible to calculate a control amount according to the above. Further, when the frequency smoothing processing unit of the third embodiment and the control calculation start determination unit of the fifth embodiment are combined, the initial control is performed when the frequency change rate with a high urgency of control is large. Since the amount is controlled to be large, there is a time margin after the control, the additional control amount can be calculated with high accuracy by increasing the number of data used for smoothing processing, and the device has high operability and the control amount is calculated with high accuracy can do.
[0202]
  Next, an eleventh embodiment of the present inventionFormThe operation of each component and means of the power system frequency stabilization device will be described with reference to FIG. 1, FIG. 2, FIG. 19 or FIG.
[0203]
The power system frequency stabilization apparatus according to the eleventh embodiment of the present invention is the control amount calculation unit 3 of the power system frequency stabilization apparatus described in the first embodiment or the second embodiment. Further, the present invention is characterized in that a control amount correction calculation means 33 for correcting the calculated control amount using various electric quantities such as the measured voltage is provided.
[0204]
Next, the overall processing flow will be described with reference to FIGS. 2, 19, and 20. The operations of the system state measurement unit 1, the frequency calculation unit 2, the control unit 4, and the system state storage unit 5, and the operations of the control amount calculation unit 3 other than the control amount correction calculation unit 33 to be described below are the first. Since this is the same as the second embodiment or the second embodiment, the description thereof will be omitted.
[0205]
In the control amount correction calculation means 33 of FIG. 19 or FIG. 20, the calculated control amount P_CUTIs corrected using various electric quantities such as the measured voltage, and the corrected control amount P is corrected._cmTo the control unit 4.
[0206]
Specifically, the voltage V stored before the frequency decrease or increase stored in the system state storage unit 5 occurs.₀And the control amount P calculated using the current voltage V_CUTIs corrected using equations (11.1) and (11.2), or is corrected using equations (11.1) and (11.3). Instead of the current voltage value, an average value of the voltages measured from the execution of the control to the present may be used.
[0207]
[Expression 15]

[0208]
Where P_CUTAs shown in FIG. 19, when combined with the first embodiment, the control amount P_CUTAs shown in FIG. 20, when combined with the second embodiment, the initial control amount P_CUT1Alternatively, the additional control amount P_CUT2It is. K_PAIs a constant that sets the ratio of the voltage characteristics of the load. K_PBIs a preset coefficient. α is a preset voltage characteristic index. K_fPIs a preset frequency characteristic constant [% / Hz]. Δf is a frequency deviation [Hz] (from the reference frequency) obtained from the measured frequency.
[0209]
Control amount P_CUTIn this case, the estimated supply-demand imbalance amount ΔP is corrected by the above method, and the control amount P is used by using the corrected ΔP._CUTMay be calculated.
[0210]
As described above, according to the eleventh embodiment of the present invention, the controlled variable is automatically corrected using the various measured electric quantities, so that the controlled variable according to the actual phenomenon can be calculated, and the device has high operability. It can be.
[0211]
  Next, a twelfth embodiment of the present inventionFormThe operation of each component and means of the power system frequency stabilization device will be described with reference to FIGS.
[0212]
A power system frequency stabilization device according to a twelfth embodiment of the present invention includes a control amount calculation unit 3 of the power system frequency stabilization device described in the first embodiment or the second embodiment. It is characterized in that it has a configuration including a control object determining means 34 for selecting a load feeder or a generator to be disconnected based on a predetermined condition set in advance.
[0213]
Next, the overall processing flow will be described with reference to FIGS. 2, 21, and 22. The operation of the system state measurement unit 1, the frequency calculation unit 2, and the system state storage unit 5 and the operation of the control amount calculation unit 3 other than the control target determination unit 34 to be described below are the same as those in the first embodiment or the first embodiment. Since it is the same as that of 2nd Embodiment, description is abbreviate | omitted.
[0214]
21 or 22 is controlled by the control amount (P_CUTOr P_CUT1Or P_CUT2) To select the load feeder or generator that is actually disconnected from the grid. For example, the active power P of each load feeder is selected from the various electric quantities measured every moment in the system state measuring unit 1 or the various electric quantities stored in the system state storage unit 5 at normal times._LOr the active power P of each generator_GThe control object is selected using.
[0215]
Here, the case where the target of load restriction is determined on the frequency lowering side will be described as an example._LThe load feeders with large load are sequentially selected as the target to be disconnected, and the active power P of the selected load feeder is selected._LTotal value P_LTAnd the control amount, and the total value P_LTIs the controlled variable (P_CUTOr P_CUT1Or P_CUT2If it is the same as or larger than), the selection of the target to be disconnected is stopped, and the load feeder selected so far is determined as the target of the release. On the other hand, in the case of increasing frequency, the active power P_GThe generators with the largest generators are selected as the target for disconnection.
[0216]
In addition, the priority of interruption is determined based on the importance that indicates whether there is a significant impact on system operation or customers when disconnected, and the magnitude of the effect of suppressing frequency decrease or increase when disconnected. It is also possible to select the control targets in order from the highest priority.
[0217]
In this case as well, for example, when the frequency lowering side is described as an example, the active power P of the selected load feeder is selected sequentially from the one with the highest priority as the target to be disconnected._LTotal value P_LTAnd control amount (P_CUTOr P_CUT1Or P_CUT2) And the total value P_LTIs the same as or larger than the control amount, the selection of the target to be disconnected is stopped, and the load feeder selected so far is determined as the target of disconnection.
[0218]
The control unit 4 outputs an opening command to the circuit breaker to which the load feeder or generator to be disconnected is connected based on the selection result of the control target determining means 34 of the control amount calculation unit 3, and the load By implementing the restriction, the frequency drop or rise is prevented.
[0219]
In addition, the frequency calculation unit 2 and the control amount calculation unit 3 may be configured as shown in FIG. 23 by appropriately combining with each unit of the third to eleventh embodiments. The actions of the individual means are the same as those in the third to seventh embodiments, so that the description thereof is omitted.
[0220]
As described above, according to the twelfth embodiment of the present invention, the load feeder or the generator to be disconnected from the system can be automatically selected, so that an apparatus with excellent operability can be obtained.
[0221]
  Next, a thirteenth embodiment of the present inventionFormA power system frequency stabilization device will be described with reference to FIGS.
[0222]
A power system frequency stabilization device according to a thirteenth embodiment of the present invention is the power system frequency stabilization device described in the first embodiment or the second embodiment. The circuit breaker switching information of the interconnection line between the local system to which it belongs and the other system of the power system (main system) and various electric quantities including current, voltage, active power, etc., and the generators in the local system are operated. Measure or collect generator disassembly information that indicates whether or not the generator is installed, and store various generator information including the rated output and inertia constant of the generator in the local system that has been set and stored in advance, and the collected generator solution. Using the parallel information, the inertia constant of the equivalent generator model when the local system side as viewed from the interconnection line is represented by one equivalent generator model is calculated by a predetermined calculation, and the calculated inertia constant is calculated as a supply-demand unbalance. And characterized in that as the inertia constant of the generator to be used for estimating the scan volume.
[0223]
FIG. 24 is an overall configuration diagram of a power system frequency stabilization device according to a thirteenth embodiment of the present invention, and FIG. 25 is a configuration diagram of a system state estimation unit.
[0224]
In FIG. 24, the system state estimation unit 130 (at the end of the electric station 107 connecting the power transmission line 102 connecting the local system 103 to which the electric station 107 to be monitored belongs and the other system (main system 101) of the electric power system is connected. For each electric station 107 to be monitored in the local system 103, a system state measurement unit 1, a frequency calculation unit 2, a control amount calculation unit 3, a control unit 4, and a system state storage are installed. The units 5 are respectively installed as one set, connected via a communication network 115 which is an information communication network, and necessary information is transmitted / received to / from each other.
[0225]
As shown in FIG. 25, the system state estimation unit 130 inputs the current, voltage, active power, and switching information of the circuit breaker 106 of the interconnection line 102, and inputs the disjunction information of the generator to determine the system state. The estimated inertia constant is output from the information communication device 114 to the communication network 115.
[0226]
As shown in the specific example shown in FIG. 26, the system state estimation unit 130 includes a connection line state measuring unit 61, a generator operating state grasping unit 62, an inertia constant calculating unit 63, a system configuration grasping unit 64, and a generator information storage unit. 65.
[0227]
The connection state measurement means 61 of the system state estimation unit 130 measures or collects various amounts of electricity including the switching information of the circuit breaker 106 of the connection line 102 and the current, voltage, active power, etc. from time to time to estimate the system state. To the system configuration grasping means 64 of the unit 130.
[0228]
Next, the generator operating state grasping means 62 uses the generator disassembly information indicating the generator operating state, that is, the switching information of the circuit breaker to which the generator is connected, as the monitoring target in the local system. Collected via the system state measuring unit 1 installed for each power plant and passed to the inertia constant calculation means 63.
[0229]
Next, in the generator information storage means 65, various generator information including the rated output of the generator in the local system, the inertia constant, etc. are set in advance and stored, and output to each means as necessary. FIG. 29 is a conceptual diagram of a generator information database in the generator information storage means 65.
[0230]
Next, in the inertia constant calculation means 63, various generator information including the rated output, inertia constant, etc. of the generator stored in the generator information storage means 65 and the generator solution collected in the generator operating state grasping means 62 are stored. Using the parallel information, the inertia constant M of the equivalent generator model 112 when the local system 103 side viewed from the interconnection line is represented by one equivalent generator model is calculated by a predetermined calculation.
[0231]
Specifically, the generator connected to the local system 103 is confirmed from the disjunction information of the generator, and various generator information such as the rated output and inertia constant of the generator connected to the system is generated. A value M obtained by weighting and averaging the inertial constant with the rated output from the following equation (13.1) using and calling from the information storage means 65_CALIs obtained by calculation.
[0232]
[Expression 16]

[0233]
Here, m is the total number of generators operating in the separation system. n is the serial number of the generator (similar to n in FIG. 29).
[0234]
Next, the system configuration grasping means 64 uses the connection line circuit breaker switching information collected by the connection line state measuring means 61 to open the connection line circuit breaker, so that the local system 103 is separated from the separated system. Make sure that In the case of a separated system, the inertia constant M of the equivalent generator model 112 obtained by the inertia constant calculation means 63 is obtained._CALIs transferred to each control amount calculation unit 3 installed for each monitoring target electric station in the local system 103.
[0235]
In each control amount calculation unit 3 installed for each monitored electric station, the inertia constant calculation means 63 calculates the inertia constant M in the above-described equation (1.1) used when estimating the supply and demand imbalance amount. Inertia constant M_CALIs used to estimate supply and demand imbalance.
[0236]
Here, when there are a plurality of interconnection lines in the local system that become separated systems when cut off, the inertia constant M_CALIs obtained as follows.
[0237]
First, the system configuration of the separation system when each interconnection line is cut off is investigated in advance, and which generator belongs to the separation system when each interconnection line is cut off. Then, a database as shown in FIG. 29 is created for each interconnection line interruption case, and is set and stored in advance in the generator information storage means 65. The connection line state measurement means 61 collects circuit breaker switching information of each connection line and passes it to the system configuration grasping means 64.
[0238]
The generator operating state grasping means 62 collects generator disassembly information indicating the operating state of the generator by the system state measuring unit 1 installed for each power plant to be monitored in the local system 103, and calculates the inertia constant. Passed to means 63.
[0239]
The system configuration grasping means 64 uses the collected circuit breaker switching information of the interconnecting lines to check the interrupted interconnecting lines, and passes the result to the inertia constant calculating means 63.
[0240]
In the inertia constant calculation means 63, the database corresponding to the disconnected interconnection line is selected from a plurality of databases set and stored in the generator information storage means 65 in advance using the result of the system configuration grasping means 64. Is used for the calculation.
[0241]
The generator connected to the separation system is confirmed by using the generator information stored in the selected generator information storage means 65, such as the rated output and inertia constant of the generator, and the collected parallel information of the generator. The inertia constant M of the equivalent generator model 112_CALIs calculated from the equation (13.1) described above.
[0242]
27 and 28 are configuration diagrams of a frequency stabilization device combined with the system state estimation unit 130. FIG.
[0243]
In the case of FIG. 27, the inertia constant M of the equivalent generator model 112 obtained by the system state estimation unit 130 is obtained._CALIs used for the calculation of the initial control calculation means 31 ′ and the correction control calculation means 32 of the control amount calculation unit 3.
[0244]
In the case of FIG. 28, the inertia constant M of the equivalent generator model 112 obtained by the system state estimation unit 130 is obtained._CALIs used for the calculation of the main control calculation means 31.
[0245]
Thus, according to the thirteenth embodiment of the present invention, the inertia constant of the equivalent generator model used when estimating the supply-demand imbalance amount can be accurately calculated, so that a highly accurate device can be obtained.
[0246]
  Next, a fourteenth embodiment of the present inventionFormThe operation of each component and means of the power system frequency stabilization device will be described with reference to FIGS. 1 and 30 to 34.
[0247]
The frequency stabilization device for a power system according to the fourteenth embodiment of the present invention is the same as the frequency stabilization device for a power system described in the second embodiment. In the case of non-operation due to, for example, in a device that operates normally, control is performed in consideration of a load limit or a power source limit that should be implemented by the failed device. FIG. 31 is a configuration diagram of an example of a frequency stabilizing device for a power system according to the fourteenth embodiment of the present invention.
[0248]
Next, the overall processing flow will be described with reference to FIGS. The operations of the system state measurement unit 1, the frequency calculation unit 2, the control unit 4, and the system state storage unit 5 and the operations other than the means described below of the control amount calculation unit 3 are the same as those in the first embodiment. Therefore, explanation is omitted.
[0249]
As shown in FIG. 31, this frequency stabilization device distributes this device at each electric station to be monitored in the local system, and estimates the supply and demand imbalance amount in the local system for each device. Calculate the load limit or power supply limit based on the estimated supply and demand imbalance, and implement control to eliminate the supply and demand imbalance in the local system. Control to (reference frequency).
[0250]
However, if an apparatus failure or the like occurs in some frequency stabilizing devices in the local system and control is not performed, the control amount of the local system as a whole may be insufficient, and the frequency may continue to decrease or increase. For this reason, in the remaining frequency stabilizing device that operates normally, if the amount of control to be controlled by the failed device is controlled by a large amount, the shortage is eliminated. The frequency can be controlled to a normal frequency (reference frequency) before the rise occurs.
[0251]
In the following, a description will be given of processing on the side of a device that operates correctly when there is a malfunctioning device. When it is necessary to perform control in consideration of the shortage in the normal operation device, the following cases can be considered. For example, if an unspecified number of devices other than one's own device fails, the initial control and additional control are not performed, or the initial control is normal for all devices, and additional control is not The case where it was not implemented with a specific many apparatus etc. can be considered.
[0252]
First, whether or not to perform additional control using various electric quantities such as the measured frequency and predetermined conditions in the control calculation start determination means 30 of the frequency stabilizing device that operates normally or not. Make a decision. For example, when it is determined whether or not to perform additional control using the measured frequency, a preset operation determination threshold value f_LMAnd the frequency f after the initial control are compared, and the frequency change rate df / dt is observed to make a determination as follows.
[0253]
df / dt ≦ 0 and f is f_LM(14.1) df / dt> 0 and f is f_LMIf it is over, it is determined that additional control is necessary. (14.2) Here, df / dt is positive when the frequency is on the increase side. On the frequency lowering side, it is positive when there is a downward trend.
[0254]
When it is determined that “additional control is necessary”, the supply / demand imbalance amount ΔP in the local system after the initial control including the shortage control is performed by the correction control calculation means 32._C2And estimated ΔP_C2Additional control amount P according to_CUT2To decide.
[0255]
Below, the supply and demand imbalance amount ΔP including the shortage control_C2The estimation method of will be described. For example, the case where neither initial control nor additional control is performed in an unspecified number of devices other than the terminal on the frequency lowering side will be described as an example.
[0256]
In the local system as shown in FIG. 31, each of the load substations A1 to A5 in the local system has P_L1To P_L5The load is almost uniformly distributed at each load substation by α (= ΔP_C1) Assuming that [%] block each time, the control amount P of the entire local system P_C1TBecomes as shown in (14.3). P_Ln・ ΔP_C1Is the controlled variable at each electric station.
[0257]
[Expression 17]

[0258]
Next, when it is assumed that there is a malfunctioning device, as shown in FIG. 32, the ratio of the correct operation device at this time is β, and β = (1−the ratio of malfunctioning device) is defined. For example, if the devices of the load substations A1 to A3 operate normally and the ratio β is 60 [%], (1-β) = (1-0.6) = 40 [%] is erroneous. This is the ratio of operating devices (A4 and A5).
[0259]
Considering that the control including the non-operational part is performed in the normal operation device, the shortage can be compensated for by increasing the control by 1 / β by itself as shown in the equation (14.4).
[0260]
[Expression 18]

[0261]
Therefore, the estimation formula of the supply and demand imbalance amount ΔPC2 after the initial control when there are a large number of unspecified malfunctioning devices is that the initial control is controlled only by β [%] (14.5) It becomes an expression. That is, the expression (2.13) may be used as it is. For simplicity, the load increase / decrease characteristic coefficient a_afAn estimation formula that does not consider is used.
[0262]
Increase / decrease characteristic coefficient a_bf, A_afSimilarly, ΔP_C2In consideration of the fact that the initial control is controlled only by β [%], the estimation formula of (14.6) or (14.7) becomes the formula (2.3) or (2.18). It can be seen that it can be used as it is.
[0263]
[Equation 19]

[0264]
According to this embodiment, even when there are an unspecified number of malfunctioning devices, it is possible to calculate the control amount including the shortage control amount in the normal operation device, so that a highly reliable frequency stabilization device is provided as a system. it can.
[0265]
Further, in the power system frequency stabilization device of the fourteenth embodiment, even when the frequency stabilization device is installed only at some of the electrical stations in the system to which the monitored electrical plant belongs. Can respond. FIG. 33 is a configuration diagram of an embodiment of a frequency stabilizing device for a power system in this case.
[0266]
The overall processing flow will be described below with reference to FIGS. 33 and 34. The operations of the system state measurement unit 1, the frequency calculation unit 2, the control unit 4, and the system state storage unit 5 and the operations other than the means described below of the control amount calculation unit 3 are the same as those in the second embodiment. Therefore, explanation is omitted.
[0267]
In the present embodiment, as shown in FIG. 33, the frequency stabilizing device is installed only at some electric stations in the local system, and the frequency is monitored independently for each device, and countermeasures are required. In this case, the control amount is calculated and controlled.
[0268]
However, the frequency stabilizing device for the power system according to the second embodiment has a shortage of control amount as a whole of the local system and the frequency is lowered unless uniform control is performed at all the electric stations belonging to the local system. Or the possibility of continuing to rise is considered. For this reason, in the present embodiment, as a system configuration in which the frequency stabilization device is installed only in some electrical stations, in each frequency stabilization device, control that should be controlled at the electrical site where the frequency stabilization device is not installed. The control amount including the amount is calculated.
[0269]
The process will be described below. First, in the initial control calculation means 31 ', the supply and demand imbalance amount ΔP of the local system to which the monitored electric power station belongs._C1Is estimated by a predetermined calculation, and the estimated supply and demand imbalance amount ΔP_C1And the total load or power generation during normal operation in the power station (= P_LOT) Using the initial control amount P_CUT1Is calculated. Since the specific action is the same as that of the first embodiment, the description thereof is omitted.
[0270]
Next, the control calculation start determination unit 30 determines whether or not to perform additional control. The specific operation is the same as that in the case of the malfunctioning frequency stabilizing device described with reference to FIGS. When it is determined that “additional control is necessary”, the correction control calculation means 32 supplies the supply and demand imbalance amount ΔP after the initial control in consideration of the electric place where the apparatus is not installed._C2And the estimated ΔP_C2Depending on the additional control amount P_CUT2To decide.
[0271]
Specifically, for example, the frequency reduction side will be described as an example. In the local system as shown in FIG. 33, each of the load substations A1 to A5 in the local system has P_L1To P_L5It is assumed that the frequency stabilizing devices are distributedly installed and monitored and controlled at load substations A1 to A3. Next, with respect to the ratio β of the normal operation device described in FIGS. 31 and 32, the device is installed = the same as the presence of the normal operation device, the device is not installed = there is a malfunctioning device. Considering the control amount that should be controlled at the electric power station where this equipment is installed, the shortage can be compensated by controlling 1 / β more at its own end as shown in equation (14.4). Can do. Similarly, the supply and demand imbalance amount ΔP after the initial control taking into account the electrical location where no device is installed_C2Considering the estimation equation, the initial control amount P_CUT1Considering that only β [%] is controlled in the local system as a whole, equations (14.5) to (14.7) are also obtained.
[0272]
In other words, even in the case of a system configuration in which this device is installed only at some electrical stations, the shortage can be compensated for by controlling 1 / β more at the electrical site where the device is installed. The estimation formula in the case where the present apparatus is installed only at the electric station is the estimation formula (2.3) or (2.18) when the present frequency stabilization apparatus is installed at all the electric stations in the local system. The same as the formula.
[0273]
Therefore, when there is a load that is not subject to monitoring, or an uncontrollable load such as an in-house load of the power plant or the active power P of the transmission loss_LOSSIt can be seen that even if there are, the additional control amount including the control amount for them can be calculated by this apparatus.
[0274]
According to the present embodiment, the system can be simplified because the frequency can be controlled to the reference frequency by suppressing the frequency drop or rise of the local system by installing this device only at some electric stations in the power system. . In addition, even if there are unmonitored loads, uncontrollable loads, or power transmission losses, additional control amounts can be calculated, including control amounts for these, providing a highly reliable and operable frequency stabilization device. it can.
[0275]
  Next, a fifteenth embodiment of the present inventionFormThe operation of each component and means of the power system frequency stabilization device will be described with reference to FIGS. 1, 2, and 35.
[0276]
The frequency stabilization device for the power system according to the fifteenth embodiment of the present invention uses the frequency change rate obtained by the control amount calculation unit of the frequency stabilization device for the power system according to the second embodiment to control the frequency stabilization device. The target frequency is reviewed. FIG. 35 is a configuration diagram of the control amount calculation unit.
[0277]
Next, the overall processing flow will be described with reference to FIGS. The operation of the system state measurement unit 1, the frequency calculation unit 2, the control unit 4, and the system state storage unit 5 and the operation other than the means described below of the control amount calculation unit 3 are the same as those in the second embodiment. Since there is, explanation is omitted.
[0278]
In the control target frequency setting means 301, the frequency change rate df / dt and a preset control target frequency switching threshold Δf_TRGIs used to switch the control target frequency according to the magnitude of the frequency change rate.
[0279]
df / dt ≧ Δf_TRG  Then
Set the control target frequency to the reference frequency (15.1)
df / dt <Δf_TRG  Then
Set the control target frequency to the frequency at the time of initial control execution (15.2)
[0280]
If it is determined that “the control target frequency is set to the reference frequency”, the initial control amount P is determined by the method described in the first embodiment._CUT1And additional control amount P_CUT2Ask for.
[0281]
If it is determined that “the control target frequency is set to the frequency at the time of initial control execution”, the additional control amount P_CUT2Is calculated as follows.
[0282]
ΔP_C1Since the estimation method is the same as that of the second embodiment, the description thereof is omitted. Initial control amount P_CUT1Is the estimated supply-demand imbalance amount ΔP_C1And the total load or total power generation amount (= P_LC1T) To calculate from equation (15.3).
[0283]
P_CUT1= P_LCIT・ ΔP_C1  ... (15.3)
[0284]
Next, in the correction control calculation means 32, ΔP as described in the second embodiment._C2Is estimated. Additional control amount P_CUT2Is the estimated supply-demand imbalance amount ΔP_C2And the total load or total power generation amount (= P_LC1T) To calculate from the equation (15.4).
[0285]
P_CUT2= P_LCIT・ ΔP_C2  ... (15.4)
[0286]
The additional control amount P obtained in this way_CUT2Is transferred to the control unit 4 and stored in the system state storage unit 5.
[0287]
In the case of “setting the control target frequency to the frequency at the time of initial control execution”, the control amount for controlling to the frequency at the time of initial control execution is calculated by the correction control calculation. That is, the imbalance between the total load amount and the total power generation amount in the local system at the time of initial control execution is estimated. On the other hand, in the case of “set the control target frequency to the reference frequency”, the control amount for controlling to the reference frequency is calculated. In other words, the imbalance at the time of system separation occurrence (the ratio of the disconnected pre-flow current to the total demand at the stationary time in the local system) is estimated. The former features the same amount of supply and demand imbalance at the time of initial control, and first prevents a decrease or increase in frequency, and controls other than this device (for example, increase / decrease in generator output) The latter is stabilized at the reference frequency, and the latter performs the initial supply and demand imbalance, that is, the equivalence control of the interconnected line prior power flow, and is stabilized at the reference frequency.
[0288]
According to the present embodiment, since the target control frequency is selected based on the frequency change rate, when the frequency reduction rate is large and the urgency of the control is high, a large amount of control is calculated, and the frequency suppression effect is enhanced. Further, when the frequency reduction rate is small and the urgency of the stabilization control is low, the control amount is calculated to be small, and the control is performed to the reference frequency by controlling the increase in the output of the generator, so that the power failure period can be minimized.
[0289]
  Next, a sixteenth embodiment of the present inventionFormThe operation of each component and means of the power system frequency stabilization device will be described with reference to FIGS. 1, 2, 30, and 36.
[0290]
In the power system frequency stabilization device according to the sixteenth embodiment of the present invention, first, in a control amount calculation unit of the power system frequency stabilization device according to the second embodiment, a load feeder or power generation The coefficient calculated from the active power of the machine is used to correct changes in various electric quantities such as the calculated frequency change rate and the measured frequency. FIG. 36 is a configuration diagram of the control amount calculation unit.
[0291]
Next, the overall processing flow will be described. The operation of the system state measurement unit 1, the frequency calculation unit 2, the control unit 4, and the system state storage unit 5 and the operation other than the means described below of the control amount calculation unit 3 are the same as those in the second embodiment. Since there is, explanation is omitted.
[0292]
Specifically, in the frequency correction unit 302, the frequency change rate df / dt obtained by the frequency calculation unit 2 is used as the load increase / decrease characteristic coefficient a._bf, A_afUsing (1), correction is performed as in the equations (16.1) to (16.3). The load increase / decrease characteristic coefficient a_bf, A_afSince the calculation method is the same as that of the second embodiment, the description thereof is omitted.
[0293]
α = K_ADJ2・ A_bf  .... (16.1)
Or
α = K_ADJ2・ A_af  .... (16.2)
Δf_RE= Α · Δf (16.3)
[0294]
Here, Δf is the frequency change rate df / dt, and the subscript RE indicates the value after correction. K_ADJ2Is a preset coefficient. The expression (16.1) is used immediately after the system separation, and the expression (16.2) is used immediately after the initial load limit or the additional load limit.
[0295]
According to the present embodiment, the frequency change rate used when estimating the supply / demand imbalance amount is automatically corrected using the coefficient representing the load increase / decrease characteristic, so the load amount has increased due to the voltage characteristic of the load. Even in this case, since the additional control amount can be calculated with high accuracy, it is possible to provide a power system frequency stabilization device with high estimation accuracy.
[0296]
Next, as the second of the present embodiment, the frequency correction unit 302 of the control amount calculation unit of the frequency stabilization device of the power system according to the second embodiment uses the coefficient calculated from the voltage. Changes in various electric quantities such as frequency change rate and measured frequencies are corrected.
[0297]
Specifically, in the frequency correction unit 302, the frequency change rate df / dt obtained by the frequency calculation unit 2 is used as the voltage variation coefficient a._bfv, A_afvIs used to correct as in the equations (16.4) to (16.6). Voltage fluctuation coefficient a_bfv, A_afvSince the calculation method is the same as that of the second embodiment, the description thereof is omitted.
[0298]
α = K_ADJ3・ A_bfv  .... (16.4)
Or
α = K_ADJ3・ A_afv  .... (16.5)
Δf_RE= Α · Δf (16.6)
[0299]
Here, Δf is the frequency change rate df / dt, and the subscript RE indicates the value after correction. K_ADJ3Is a preset coefficient. (16.4) is used immediately after the system separation, and (16.5) is used immediately after the initial load limit or additional load limit.
[0300]
According to this embodiment, in order to automatically correct the frequency change rate used when estimating the supply and demand imbalance amount using the coefficient representing the voltage fluctuation characteristic, the voltage reduction and control after the system separation were performed. Since the influence of the voltage rise that occurs at the time can be removed and the additional control amount can be calculated with high accuracy, it is possible to provide a frequency stabilization device for a power system with high estimation accuracy.
[0301]
  Next, a seventeenth embodiment of the present inventionFormThe operation of each component and means of the power system frequency stabilizing device will be described with reference to FIGS. 1, 2, 4 and 37. FIG.
[0302]
The frequency stabilization device for a power system according to the seventeenth embodiment of the present invention includes a control amount calculation unit of the frequency stabilization device for a power system according to the second embodiment. The inertia constant of the generator was estimated. FIG. 37 is a block diagram of an embodiment of the control amount calculation unit of the frequency stabilizer for the power system according to the present invention.
[0303]
The overall process flow will be described below. The operation of the system state measurement unit 1, the frequency calculation unit 2, the control unit 4, and the system state storage unit 5 and the operation other than the means described below of the control amount calculation unit 3 are the same as those in the second embodiment. Since there is, explanation is omitted.
[0304]
In the inertia constant estimation means 35 shown in FIG. 37, the equivalent power generation when the local system side seen from the interconnection line is represented by one generator as shown in FIG. The inertia constant M of the machine model is estimated. Note that, in the equation (2.10), the load increase / decrease characteristic coefficient a calculated from the active power_bf, A_afInstead of the load characteristic increase / decrease coefficient a calculated from the measured voltage_bfv, A_afvMay be used. As described in the second embodiment, the load amount Pe (t +) after the initial load limit is the total load amount P at the normal time in the electric station._LOTTo initial control amount P_CUT1And thus Pe (t +) = P_L(T +) = (P_L0-P_CUT1) = (1−ΔP_C1).
[0305]
Estimated inertia constant M_estIs stored in the system state storage unit 5, and when the frequency lowers or rises at a later date, the initial control calculating means 31 'causes the supply / demand unbalance amount ΔP before the initial control to be obtained._C1Is used as M in the estimation formula (1.1). In this way, since the inertia constant of the real system can be used, the supply and demand imbalance amount can be estimated with higher accuracy.
[0306]
According to the present embodiment, the equivalent generator model in the case where the generator in the system to which the monitored electric plant belongs is represented by only one piece of information that can be measured or collected only at the end of the monitored electric plant. Inertia constant can be estimated.
[0307]
Next, operation of each component and means of the power system frequency stabilization device according to the eighteenth embodiment of the present invention will be described with reference to FIGS. 1, 2, 30 and 38. FIG.
[0308]
The power system frequency stabilization device according to the eighteenth embodiment of the present invention performs initial or additional load limitation or power source limitation in the control amount calculation unit of the power system frequency stabilization device according to the second embodiment. The calculated control amount is corrected using a coefficient calculated from the active power of the load feeder or the generator before and after the execution. FIG. 38 is a configuration diagram of the control amount calculation unit.
[0309]
Next, the overall processing flow will be described. The operations of the system state measuring unit 1, the frequency calculating unit 2, the control unit 4, and the system state storage unit 5 and the operations of the control amount calculation unit 3 other than the control amount correction calculation unit 33 to be described below are as follows. Since it is the same as the embodiment, the description is omitted.
[0310]
In the control amount correction calculation means 33, the calculated control amount P_CUT(Additional control amount P_CUT2), Load increase / decrease characteristic coefficient a_afIs corrected as shown in equation (18.1). The load increase / decrease characteristic coefficient a_afSince the calculation method is the same as that of the second embodiment, the description thereof is omitted.
[0311]
Specifically, the load increase / decrease characteristic coefficient a_afThe calculated control amount P using_CUTIs corrected using equation (18.1).
[0312]
[Expression 20]

[0313]
Where α_pcIs a preset coefficient, P_CUTIs the additional control amount P_CUT2It is.
[0314]
Control amount P_CUTInstead of correcting the estimated supply-demand imbalance amount ΔP (ΔP_C1Or ΔP_C2) Is corrected by the above method, and the control amount P is used by using the corrected ΔP._CUTMay be calculated.
[0315]
According to the present embodiment, since the control amount is automatically corrected using a coefficient representing the load increase / decrease characteristic, the additional control amount can be accurately calculated even when the load amount changes due to the voltage characteristic of the load. It is possible to provide a power system frequency stabilization device with high estimation accuracy in consideration of the voltage characteristics of the load.
[0317]
【The invention's effect】
  Claim 1According to the invention, it is possible to estimate the supply and demand imbalance amount in the system to which the monitored electric power plant belongs only by the total value of the control amount that has been shut off and the frequency change rate, so there is no need to set parameters for the calculation. Because the control amount is calculated from the estimated supply and demand imbalance amount, it is possible to cope with changes in the system status such as increase or decrease in demand, so that the burden on the system operator can be reduced. Can be prevented. In addition, it is possible to estimate the supply and demand imbalance by using only information that can be measured or collected only at the monitored power station end, and calculate the control amount based on the estimated supply and demand imbalance. It is not necessary to collect the information and a wide-area information transmission network is unnecessary, and the system scale can be reduced. Further, since monitoring and control can be performed individually for each electric station to be monitored, it is possible to provide a device with a simple device configuration, high controllability and excellent operability and maintainability.
[0318]
Also,Claim 2According to the invention, it is possible to estimate the supply and demand imbalance considering the increase or decrease of the load in the local system due to the voltage change caused by the system separation or the increase or decrease of the load due to the voltage fluctuation caused by the load restriction or power supply restriction in the local system. Therefore, the estimation accuracy can be increased. Further, since the frequency smoothing process for removing the influence of the voltage fluctuation can be deleted or the data section length used for the smoothing process can be shortened, the additional control amount can be calculated in a short time.
[0319]
  Also,Claim 3According to the present invention, since the increase / decrease characteristic coefficient of the load is obtained as the voltage fluctuation coefficient calculated from the measured voltage, the supply and demand imbalance amount can be estimated in consideration of the voltage fluctuation, so that the estimation accuracy can be improved. Further, since the frequency smoothing process for removing the influence of the voltage fluctuation can be deleted or the data section length used for the smoothing process can be shortened, the additional control amount can be calculated in a short time.
[0320]
  Also,Claim 4According to the invention, since the smoothing process is applied to the various electric quantities used for obtaining the supply / demand imbalance amount, the supply / demand imbalance amount can be estimated with high accuracy even when the frequency fluctuates abnormally. Since variations in results are prevented, a highly accurate and highly reliable device can be provided.
[0321]
  Also,Claim 5According to the invention, since the calculation is performed using the predicted future frequency and its frequency change rate, the calculation result can be obtained at an earlier time point than when calculating using the actual measurement value, and the control is performed at an earlier time point. And an apparatus that stabilizes abnormal fluctuations in frequency in a short time.
[0322]
  Also,Claim 6According to this invention, since control can be performed in stages based on preset conditions, control according to system operation is possible, and an apparatus with high operability can be obtained.
[0323]
  Also,Claim 7According to the invention, since the operating conditions can be different among the plurality of frequency stabilizing devices, it is possible to prevent more than necessary disconnection by the coordinated stabilization control.
[0324]
  Also,Claim 8According to the invention, the correction control calculation is locked while the transient voltage rise after the load limit occurs, so the power consumption of the load increases with the voltage rise and the control amount is excessively calculated. Even in the case of excessive control, excessive control can be prevented.
[0325]
  Also,Claim 9According to the invention, the correction control calculation is locked while the transient voltage rise after the load limit occurs, so the power consumption of the load increases with the voltage rise and the control amount is excessively calculated. Even in the case of excessive control, excessive control can be prevented.
[0326]
  Also,Claim 10According to this invention, since the inertia constant of the equivalent generator model used when estimating the supply and demand imbalance amount is adjusted using the magnitude of the frequency change rate, the control amount according to the actual phenomenon can be calculated.
[0327]
  Also,Claim 11According to this invention, since the inertia constant of the equivalent generator model used when estimating the supply and demand imbalance amount is adjusted using the magnitude of the frequency change rate, the control amount according to the actual phenomenon can be calculated.
[0328]
  Also,Claim 12According to the invention, since the control amount is corrected using the various measured electric quantities, the control amount in accordance with the actual phenomenon can be calculated and the device can be made highly operational.
[0329]
  Also,Claim 13According to the invention, since the load feeder or the generator to be disconnected from the system can be selected, it is possible to provide an apparatus with excellent operability.
[0330]
  Also,Claim 14According to this invention, since the inertia constant of the equivalent generator model used when estimating the supply and demand imbalance amount can be accurately calculated, a highly accurate device can be obtained.
[0331]
  Also,Claim 15According to the invention, even when there are an unspecified number of malfunctioning devices, it is possible to calculate the control amount including the shortage control amount in the correct operation device, so that it is possible to provide a highly reliable frequency stabilization device as a system.
[0332]
  Also,Claim 16According to the invention, by installing this apparatus only at some electric stations in the electric power system, it is possible to suppress the frequency decrease or increase of the local system and control it to the reference frequency, thereby simplifying the system. In addition, even if there are unmonitored loads, uncontrollable loads, or power transmission losses, additional control amounts can be calculated, including control amounts for these, providing a highly reliable and operable frequency stabilization device. it can.
[0333]
  Also,Claim 17According to this invention, since the target control frequency is selected based on the frequency change rate, when the frequency reduction rate is large and the urgency of the control is high, a large amount of control is calculated, and the frequency suppression effect is enhanced. Further, when the frequency reduction rate is small and the urgency of the stabilization control is low, the control amount is calculated to be small, and the control is performed to the reference frequency by controlling the increase in the output of the generator, so that the power failure period can be minimized.
[0334]
  Also,Claim 18According to the invention, since the frequency change rate used when estimating the supply / demand imbalance amount is automatically corrected using the coefficient representing the load increase / decrease characteristic, even when the load amount increases due to the voltage characteristic of the load. Since the additional control amount can be calculated with high accuracy, it is possible to provide a power system frequency stabilization device with high estimation accuracy.
[0335]
  Also,Claim 19The power system frequency stabilization device automatically corrects the frequency change rate used when estimating the supply and demand imbalance using a coefficient that expresses the voltage fluctuation characteristics, so that the effects of voltage fluctuations can be eliminated. Since the additional control amount can be calculated with high accuracy, it is possible to provide a power system frequency stabilization device with high estimation accuracy.
[0336]
  Also,Claim 20According to the invention, the inertia constant of the equivalent generator model when the generator in the system to which the monitored electric plant belongs is represented by only one piece of information that can be measured or collected only at the end of the monitored electric plant. Can be estimated.
[0337]
  Also,Claim 21According to the invention, since the control amount is automatically corrected using the coefficient representing the load increase / decrease characteristic, the additional control amount can be accurately calculated even when the load amount changes due to the voltage characteristic of the load. It is possible to provide a power system frequency stabilization device with high estimation accuracy in consideration of voltage characteristics.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of a power system frequency stabilization apparatus to which the present invention is applied.
FIG. 2 is a configuration diagram showing an embodiment of a power system frequency stabilization device of the present invention.
FIG. 3 is a configuration diagram of a frequency stabilization device for a power system according to the first embodiment of the present invention.
FIG. 4 is a diagram showing an equivalent system model handled by a frequency stabilization device for a power system to which the present invention is applied.
FIG. 5 is a configuration diagram of a power system frequency stabilization apparatus according to a second embodiment of the present invention.
FIG. 6 is a conceptual diagram of an increase / decrease characteristic coefficient of a load according to the present invention.
FIG. 7 is a configuration diagram of a frequency stabilizing device for a power system according to a third embodiment of the present invention.
FIG. 8 is a configuration diagram of a frequency stabilizing device for a power system according to a fourth embodiment of the present invention.
9 is a configuration diagram of a power system frequency stabilization device according to another embodiment of FIG. 8;
FIG. 10 is a configuration diagram of a frequency stabilizing device for a power system according to a fifth embodiment of the present invention.
FIG. 11 is a first flowchart showing a process of the frequency stabilizing device for the power system of FIG. 10;
12 is a second flowchart showing processing of the power system frequency stabilization device of FIG. 10; FIG.
13 is a configuration diagram of a frequency stabilizing device for a power system according to another embodiment of FIG.
14 is a first flowchart showing processing of the frequency stabilizing device for the power system of FIG. 13; FIG.
15 is a second flowchart showing processing of the power system frequency stabilization device of FIG. 13; FIG.
16 is a partial flowchart showing a process of a power system frequency stabilizing device according to another embodiment of the power system frequency stabilizing device of FIG. 13; FIG.
FIG. 17 is a configuration diagram of a frequency stabilizing device for a power system according to a ninth embodiment and a tenth embodiment of the present invention.
FIG. 18 is a configuration diagram of a frequency stabilizing device for a power system according to a ninth embodiment and a tenth embodiment of the present invention.
FIG. 19 is a configuration diagram of a frequency stabilizing device for a power system according to an eleventh embodiment of the present invention.
20 is a configuration diagram of a power system frequency stabilization device according to another embodiment of the power system frequency stabilization device of FIG. 19;
FIG. 21 is a configuration diagram of a frequency stabilization device for a power system according to a twelfth embodiment of the present invention.
22 is a configuration diagram of a power system frequency stabilization device according to another embodiment of the power system frequency stabilization device of FIG. 21. FIG.
FIG. 23 is a configuration diagram of a power system frequency stabilization device according to another embodiment of the power system frequency stabilization device of FIG. 22;
FIG. 24 is an overall configuration diagram of a frequency stabilizing device for a power system according to a thirteenth embodiment of the present invention.
25 is an explanatory diagram of a system state estimation unit provided in the power system frequency stabilization device of FIG. 24. FIG.
26 is a specific configuration diagram of a system state estimation unit in FIG. 25. FIG.
27 is a specific configuration diagram of the frequency stabilization device for the power system of FIG. 24. FIG.
28 is another specific configuration diagram of the power system frequency stabilization device of FIG. 24. FIG.
29 is a configuration diagram of generator information storage means provided in the system state estimation unit of FIG. 26. FIG.
FIG. 30 is a configuration diagram of a frequency calculation unit and a control amount calculation unit of a frequency stabilization device for a power system according to a fourteenth embodiment of the present invention.
FIG. 31 is a configuration diagram of a frequency stabilizing device for a power system according to a fourteenth embodiment of the present invention.
FIG. 32 is a diagram for explaining a ratio β of a frequency stabilizing device that operates normally.
FIG. 33 is a configuration diagram of a frequency stabilization device for another power system according to the fourteenth embodiment of the present invention.
FIG. 34 is a configuration diagram of a control amount calculation unit of a frequency stabilizer for a power system according to a fourteenth embodiment of the present invention.
FIG. 35 is a configuration diagram of a control amount calculation unit of a frequency stabilizer for a power system according to a fifteenth embodiment of the present invention.
FIG. 36 is a configuration diagram of a control amount calculation unit of a frequency stabilizer for a power system according to a sixteenth embodiment of the present invention.
FIG. 37 is a configuration diagram of a control amount calculation unit of a frequency stabilizer for a power system according to a seventeenth embodiment of the present invention.
FIG. 38 is a configuration diagram of a control amount calculation unit of a frequency stabilizer for a power system according to an eighteenth embodiment of the present invention.
FIG. 39 is a flowchart showing processing of a conventional power system frequency stabilizing device;
FIG. 40 is an explanatory diagram of an example of setting operating conditions in the case of stabilizing the frequency lowering side of the conventional frequency stabilizing device for a power system.
[Explanation of symbols]
1 System state measurement unit
2 Frequency calculator
3 Control amount calculator
4 Control unit
5 System state storage
21 Frequency calculation means
22 Frequency smoothing processing means
23 Frequency fluctuation prediction means
30 Control calculation start judging means
31 Main control calculation means
31 'initial control calculation means
32 Correction control calculation means
33 Control amount correction calculation means
34 Control object determining means
35 Inertia constant estimation means
61 Interconnection line state measuring means
62 Generator operation state grasping means
63 Inertia constant calculation means
64 System configuration grasping means
65 Generator information storage means
100 Power system
101 Main system
102 Interconnection line
103 Local system
104 Transmission line
105 Stabilization control line
106 Circuit breaker
107 Electricity station
108 Transmission line
109 Generator
110 load
111 Measuring instrument
112 Equivalent generator model
113 Equivalent load model
114, 116 Information communication device
115 Communication network
120 Frequency stabilizer
130 System State Estimator
301 Control target frequency setting means
302 Frequency correction means
310 Calculation condition setting means
50 Operating condition setting example

Claims (21)

Necessary in order to prevent fluctuations in the obtained frequency by performing predetermined calculations using various amounts of electricity including the measured system frequency at electrical stations such as substations or power plants that are monitored by the power system In the frequency stabilization device of the power system that cuts off the generator or the load by the limited load limit or power supply limit,
Based on the frequency change rate of the monitoring target power station and the inertia constant of the equivalent generator in the system to which the monitoring target power station belongs, means for estimating the supply and demand imbalance amount in the system by a predetermined calculation;
Means for determining an initial load limit amount or an initial power supply limit amount according to the supply and demand imbalance amount estimated by the means;
When the frequency of the system to be monitored fluctuates by a predetermined magnitude after the initial load limit amount or the initial power limit amount, the frequency change rate and the load limit amount or the power source before and after the execution are changed. Means for re-estimating the supply and demand imbalance in the system using the limit amount;
Means for determining an additional load limit amount or an additional power source limit amount according to the supply-demand imbalance amount re-estimated by this means;
Means for re-estimating the supply and demand imbalance amount of the additional system determined by this means and determining the additional load limit amount or power supply limit amount according to a predetermined condition. A frequency stabilization device for a power system, which is individually monitored and controlled for each target electric station. In the means for reestimating the supply and demand imbalance amount in the system, the frequency separation rate before and after the load limit or power limit is implemented, the load limit amount or the power limit amount, and the system separation and load limit or power limit 2. The power system frequency stabilization apparatus according to claim 1 , wherein a supply / demand imbalance amount in the system is estimated also using the accompanying load increase / decrease characteristic coefficient. The frequency stabilization device for a power system according to claim 2 , wherein a load increase / decrease characteristic coefficient associated with the system separation and load limitation or power source limitation is calculated based on the measured voltage. The power system according to claim 1 or 2 , wherein a predetermined smoothing process is performed on various electric quantities used for calculating the frequency change rate or calculating the supply and demand imbalance. Frequency stabilization device. The frequency of the power system according to any one of claims 1 to 4, wherein the supply and demand imbalance amount is estimated using a future frequency change rate predicted by predicting a future frequency of the system. Stabilizer. When it is determined that the predetermined condition set in advance is satisfied, the initial or additional calculation for estimating the supply and demand imbalance amount is started, and the load limiting amount or the power control amount is determined by the obtained initial or additional supply and demand unbalance amount. The frequency stabilization device for a power system according to any one of claims 1 to 3 , wherein the frequency stabilization device is determined. 7. The electric power system according to claim 6, wherein calculation for individually estimating the supply and demand imbalance amount is started in accordance with a tolerance for frequency fluctuations of a load feeder or a generator connected to each monitored electric station. Frequency stabilization device. After starting the initial or additional calculation for estimating the supply / demand imbalance amount, determining the load limit amount or the power supply limit amount based on the obtained initial or additional supply / demand imbalance amount, and shutting off the generator or the load , subsequently, again, of the claims 1 to 3, wherein the locking the operation of estimating the supply unbalance amount according to a predetermined condition set in advance when performing the operation of estimating the supply unbalance amount Frequency stabilizer for any power system. After starting the initial or additional calculation for estimating the supply / demand imbalance amount, determining the load limit amount or the power supply limit amount based on the obtained initial or additional supply / demand imbalance amount, and shutting off the generator or the load Subsequently, when the calculation for estimating the supply / demand imbalance amount is performed again, the calculation for estimating the supply / demand imbalance amount is locked when the measured voltage becomes a preset condition. The frequency stabilization device for a power system according to claim 8 . Based on a predetermined condition set in advance at the time of estimation of demand unbalance amount, claims 1 to 3, wherein an adjustment be performed to select the inertia constants of the preset plurality of generators A frequency stabilizing device for any of the power systems described. The power system according to any one of claims 1 to 3 , wherein when the supply and demand imbalance amount is estimated, the inertia constant of the generator is increased or decreased based on the magnitude of the frequency change rate. Frequency stabilizer. The power supply limit amount or the load limit amount is corrected by performing a predetermined calculation based on various amounts of electricity when the frequency is stable and various amounts of electricity when the frequency fluctuates. The frequency stabilization apparatus of the electric power system of 1 description . Based on a predetermined condition set in advance, the frequency stabilizer of any one of the power system of claim 1 to claim 3, wherein the selecting the generator to the load feeder or power limit load limit. Switching information of circuit breakers between the local system to which the monitored power station belongs and other main systems of the power system, various electric quantities including current, voltage, active power, etc., and generators in the local system Collecting generator disassembly information indicating whether the generator is in operation, as well as various generator information including the rated output and inertia constant of the generator in the local system set and stored in advance and the collected power generation Using the parallel information of the machine, the inertia constant of the equivalent generator model when the local system side viewed from the interconnection line is represented by one equivalent generator model is calculated by a predetermined calculation, and the calculated inertia constant is frequency stability KaSo of any power system of claim 1 to claim 3, wherein further comprising a system condition estimating unit according to the inertia constant of the generator in said system for use in estimating the supply unbalance amount . If some frequency stabilizers in the isolated system are inoperable due to a failure, etc., consider the load limit or power supply limit that the failed frequency stabilizer must perform in the frequency stabilizer that operates normally 4. The frequency stabilization device for a power system according to claim 1 , wherein control is performed as described above. The frequency stabilization device for a power system according to any one of claims 1 to 3, wherein the apparatus is installed only at some of the electric stations in the system to which the electric station to be monitored belongs. The frequency stabilization device for a power system according to any one of claims 1 to 3 , wherein the control target frequency is reviewed by using the obtained frequency change rate. Using the coefficients calculated from the active power of the load feeder or generator before and after the initial or additional load limit or power supply limit at the steady state before the accident occurs, various electric quantities such as the calculated frequency change rate The frequency stabilization device for a power system according to claim 1 , wherein a change, a measured frequency, and the like are corrected. Changes in various quantities of electricity, such as the calculated frequency change rate, measured frequencies, etc., using the coefficients calculated from the voltage at the steady state before the accident and at the beginning or before or after additional load limiting or power limiting. The frequency stabilization device for a power system according to claim 1, wherein: The frequency stabilization device for a power system according to claim 2 or 3, wherein an inertia constant of a generator in a system to which an electric station to be monitored belongs is estimated. It is characterized in that the calculated control amount is corrected by using a coefficient calculated from the active power of the load feeder or generator at the normal time before the accident occurrence and before or after the initial or additional load limitation or power source limitation. The frequency stabilization device for a power system according to claim 1 .

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