JP3965264B2 - Hydropower plant hydraulic machine with surge tank - Google Patents

Description

【００４８】
これらの式は、無次元変数ｖ₁，ｖ₂，ｖ₃，ｖ₄，ｈ_fu，ｈ_fL，ｈ_u，ｈ_L，ｐ_t ，ｑ，ｙを変数とする線形近似式であり、これら変数の高次項はnegligible smallとして省略している。
【００４９】
【数１６】
ｖ₁＝−ｇ・Ｈ₀・ｈ_fu／(Ｌ₁・Ｖ₁₀・Ｓ） …(１６)
【００５０】
【数１７】
ｈ_fu＝(Ａ₁・Ｖ₁₀・ｖ₁−Ａ₂・Ｖ₂₀・ｖ₂)／(Ｈ₀・Ａ_fu・Ｓ） …(１７）
【００５１】
【数１８】
ｖ₂＝ｇ(Ｈ₀・ｈ_fu−Ｈ_u0・ｈ_u)／(Ｌ₂・Ｖ₂₀・Ｓ） …(１８)
【００５２】
【数１９】
ｐ_t＝ｈ＋ｑ …(１９)
【００５３】
【数２０】
ｈ＝(Ｈ_u0ｈ_u−Ｈ_L0ｈ_L)／(Ｈ_u0・Ｈ_L0)＝(Ｈ_u0ｈ_u−Ｈ_L0ｈ_L)／Ｈ₀
…(２０)
【００５４】
【数２１】
ｑ＝ｙ＋０.５ｈ …(２１)
【００５５】
【数２２】
ｑ＝ｖ₂＝ｖ₃ …(２２)
【００５６】
【数２３】
ｖ₃＝ｇ(Ｈ_L0・ｈ_L−Ｈ₀・ｈ_fL)／(Ｌ₃・Ｖ₃₀・Ｓ） …(２３)
【００５７】
【数２４】
ｖ₄＝ｇ・Ｈ₀・ｈ_fL／(Ｌ₄・Ｖ₄₀・Ｓ） …(２４)
【００５８】
【数２５】
ｈ_fL＝(Ａ₃・Ｖ₃₀・ｖ₃−Ａ₄・Ｖ₄₀・ｖ₄)／(Ｈ₀・Ａ_fL・Ｓ） …(２５)
このことから、図２に示す水力プラントのガバナの制御対象の線形化モデルは、図３のように示すことができる。すなわち、ガイドベーン(水量制御手段)の無次元化された開度ｙによって無次元化された流量変化ｑが発生し、これにより無次元化された上流側サージタンクの水位ｈ_fu，無次元化された下流側サージタンクの水位ｈ_fLが応動することが解る。図３に示す上サージングブロック図，下サージングブロック図は、それぞれ図４，図５に示すように構成されている。なお、流量変化に対する上流側サージタンク水位，下流側サージタンク水位の応答はいずれも典型的な正弦波発生回路になっており、上流側サージタンクサージングの周期，下流側サージタンクサージングの周期はそれぞれ２π√(Ａ_fu・Ｌ₁／Ａ₁・ｇ)，２π√(Ａ_fL・Ｌ₄／Ａ₄・ｇ)となる。
【００５９】
図１は本実施例のガバナの制御ブロック線図である。１はポンプ水車１００の回転速度Ｎを検出する速度検出部、Ｘ_n は速度検出部１で検出された速度検出信号、２は回転速度の基準値を設定する速度調整部、ｘ₀ は速度調整部２から出力される設定値、３は設定値ｘ₀ と速度検出信号Ｘ_n と後述する速度調定率設定部からの復元信号Ｘ_σとの加算器、Ｘ_εは加算器３で算出された信号ですぐ下流のＰＩＤ演算回路の入力信号、２０は上流側サージタンク用サージングセンサー、４ａは通常使用する比例演算要素（Ｐ要素）、４ｂはサージングセンサーが動作した時、すなわち、サージング抑制を行う場合に使用する比例演算要素(Ｐ要素)を示す。なお、前者の比例演算要素のゲインＫ_pa＜後者の比例演算要素のゲインＫ_pbとなっている。５ａは通常使用する積分演算要素（Ｉ要素）、５ｂはサージングセンサーが動作した時、すなわち、サージング抑制を行う場合に使用する積分演算要素（Ｉ要素）を示し、前者の積分ゲインＫ_iaと後者の積分ゲインＫ_ibとはＫ_ia＜Ｋ_ibとなっている。１９ａ，１９ｂはそれぞれ比例演算要素４ａ，４ｂ，積分演算要素５ａ，５ｂの前段に設けられたサージングセンサー２０の接点で、サージングセンサー２０が動作した時にスイング動作して、比例演算要素４ａを開き比例演算要素４ｂを閉じ、積分演算要素５ａを開き積分演算要素５ｂを閉じ、比例演算要素，積分演算要素共に切換える。
【００６０】
６は微分演算要素（Ｄ要素）を示し、その出力信号Ｚ_d ，比例演算要素の出力信号Ｚ_p ，積分演算要素の出力信号Ｚ_i は、加算部７で加算される。この比例演算要素の出力信号Ｚ_p ，積分演算要素の出力信号Ｚ_i ，微分演算要素の出力信号Ｚ_d を総合した信号は、ガイドベーン開度指令Ｚであり、このガイドベーン開度指令Ｚに実際のガイドベーン開度Ｙがフィードバックされ、加算部８で偏差がとられる。この偏差信号Ｙ_{ε 1} は、リミッター９を介して油圧サーボモータ１０に入力される。リミッター９のθ_R はガイドベーンの開速度をθ_R・Ｃ_yに、θ_L は閉速度をθ_l・Ｃ_y に制限するためのものであり、リミッター９の出力信号Ｙ_{ε 2}は偏差信号Ｙ_{ε 1} を上記開閉速度制限を考慮して制限した信号となっている。油圧サーボモータ１０は一種の油圧増幅器になっており、伝達関数では一次遅れ要素を構成し、ガイドベーン開度指令ｚを増幅して充分なストロークと操作力をもつガイドベーン開度Ｙに変換し、水量制御手段であるガイドベーンを直接操作する。
【００６１】
実際のガイドベーン開度Ｙはフィードバックされ、加算部１１で、出力調整部１３からのガイドベーン開度設定信号Ｙ_a との偏差が与えられる。もし実際のガイドベーン開度Ｙがガイドベーン開度設定信号Ｙ_a に達していない場合、すなわち、Ｙ＜Ｙ_a の場合にはその差がゼロになるまでガバナのＰＩＤ演算部に開信号σ(Ｙ_a −Ｙ)が送り続けられるので、やがてはＹ＝Ｙ_a となりその段階で落ち着く。開信号σは速度調定率設定部１２で設定され、復元信号Ｘ_σを出力する。この開信号σは速度検出信号Ｘ_n の変化に対するガイドベーン開度Ｙの変化の割合を決めるゲインで、一般には電力系統の中でのプラントの役割を考慮して一度決めたら変更されないものである。
【００６２】
１４は図３に示すブロック線図全体を示し、実際のガイドベーン開度Ｙがフィードバックされている。このブロック線図１４は、前述したように、簡単に表現すると水路系を含むポンプ水車の制御ブロック線図を示す。ブロック線図１４の出力である水車の出力Ｐ_t と後述する総合負荷ＬΣとの偏差がとられ、この偏差は回転部慣性効果の算出部１６に入力され、回転速度Ｎを算出する。この回転速度Ｎは、自己制御性の演算部１７ａ，電力系統からの同期化作用の演算部１７ｂにフィードバックされる。
【００６３】
演算部１７ｂでは、回転速度Ｎが定格速度（同期速度）Ｎ₀ から外れない様に電力系統が連れ戻す同期化作用を示す負荷電力Ｒ_L を算出する。Ｌは水車軸に直結された発電機に与えられる外部負荷であり、この外部負荷Ｌと負荷電力Ｒ_L が加算され、発電機負荷Ｐ_g が算出される。ポンプ水車１００の自己制御性の演算部１７ａでは、回転速度上昇に伴い増加する機械損や効率低下等を総合した特性を演算しており、回転速度変化に伴う自己制御性による水車出力のロスＲ_T を算出している。
【００６４】
水車からみれば発電負荷Ｐ_g だけでなくロスＲ_T も一種の負荷のようにみなすことができ、水車の出力Ｐ_t を消費する総合負荷ＬΣ＝Ｐ_g ＋Ｒ_T とみなすことができる。発電負荷Ｐ_g とロスＲ_T が加算されて総合負荷ＬΣを算出し、さらに水車の出力Ｐ_t との偏差がとられて、（Ｐ_t −ＬΣ）が回転部慣性効果の算出部１６に入力され、回転部慣性効果の算出部１６の出力として回転速度Ｎが算出される。
【００６５】
ところで図１に示すガバナには外部から与えられる信号として、発電機に与えられる外部負荷Ｌと出力調整部１３から与えられるガイドベーン開度設定信号Ｙ_a の２つの信号がある。外部負荷Ｌは、その変動によって回転速度Ｘ_n の速度変動を生じさせる。一方、出力調整部１３に入力される信号の代表的なものがＡＦＣ（自動周波数制御）であり、ＡＦＣの場合には専ら電力系統の周波数制御の観点で出される指令であるので、サージング異常加振等の水力プラントの特殊事情は感知せずに出され、図示してない遠方の中央制御所から遠隔操作で与えられる。従って、回転速度Ｘ_n ，ガイドベーン開度設定信号Ｙ_a いずれの信号によっても上流側，下流側いずれのサージタンクも異常加振される可能性があるので、サージングセンサーは両信号の総合効果を監視できるように両信号の合流点である加算器３より下流側に配置している。
【００６６】
図６は、図１に示すガバナのＰＩＤ演算部への入力信号Ｘ_εを入力しているサージングセンサー２０の一例を示す図である。２０Ａは絶対値演算部、２０Ｂは入力が０.００４(ｐ_u)以上の時には１をそれ以下の時には０を出力するスイッチである。２０Ｃは、スイッチ２０Ｂの出力が１の時は０を選択し、スイッチ20Ｂの出力が０の時は０.２ を選択する信号選択要素、２０Ｄはスイッチ２０Ｂの出力と信号選択要素２０Ｃの出力との偏差をとる加算部、２０Ｆは加算部２０Ｄの出力信号を積分する積分要素、２０Ｅは積分要素２０Ｆの前段に設けられ、積分要素２０Ｆの上限が２５を超えない様に、下限が０を超えない様に積分要素20Ｆへ送る信号の通過／阻止を司るリミッター、２０Ｇは積分要素２０Ｆの出力が設定値の１０以上の場合にサージングセンサーをＯＮし、１０未満の場合にサージングセンサーをＯＦＦするサージングセンサー作動部である。
【００６７】
次に、図６に示すサージングセンサーの動作について図７，図８のサージングセンサーの動作説明図を用いて説明する。図７に示すレコード１はガバナのPID演算部への入力信号Ｘ_εを、レコード２はガバナのＰＩＤ演算部の出力信号Ｚを、レコード３は積分要素２０Ｆの出力信号を、レコード４はサージングセンサー作動部２０Ｇの出力信号を夫々示す。又、図８に示すレコード１は回転速度Ｎを、レコード２はガイドベーン開度設定信号Ｙ_a を、レコード３はガイドベーン開度Ｙを示す。なお、この場合、図８に示すレコード２のように出力調整部１３から与えられるガイドベーン開度設定信号Ｙ_a がサージング加振信号となっている。
【００６８】
時点ｔ_aでＰＩＤ演算部の入力Ｘ_ε＞０.００４となるとスイッチ２０Ｂは１を出力する。すると信号選択要素２０Ｃは０を出力する。この結果、加算部２０Ｄの出力は１となり、積分要素２０Ｆが積分を開始し、レコード３で示す積分要素２０Ｆの出力値は直線的に上昇する。時点ｔ_b になると、積分要素２０Ｆの出力が１０を超えるのでこの段階でサージングセンサーがＯＮする。なお時点ｔ_c になると積分要素２０Ｆの出力が２５に達すると、リミッター２０Ｅの作用で直ちに上昇が止む。時点ｔ_dになるとＰＩＤ演算部の入力Ｘ_ε＜０.００４となり、スイッチ２０Ｂは０を出力し、信号選択要素２０Ｃは０.２ を出力するので加算部２０Ｄの出力は−０.２ となり、積分要素２０Ｆの出力は上昇時の１／５勾配で降下し始める。時点ｔ_eになると再びＰＩＤ演算部の入力Ｘ_ε＞０.００４となり、積分要素２０Ｆの出力が上昇を始める。
【００６９】
絶対値演算部２０Ａで絶対値を採っている理由は、ＰＩＤ演算部の入力Ｘ_εが正（水量制御手段を開く場合）の場合でも、負（水量制御手段を閉じる場合）の場合でも最終的な水量変化が同じであれば、水位上昇から始まるか、下降から始まるかの差はあれ同じ振幅のサージングになるためである。もちろん前述したように、精度が多少悪くなってもサージングセンサーをできるだけ簡単化できるためである。
【００７０】
スイッチ２０Ｂで｜Ｘ_ε｜の振幅を考慮している理由は正負に関係なく振幅が大きければ大きいほどサージングも大きくなるためである。また信号選択要素２０Ｃの設定値０.２ を大きくすると積分要素２０Ｆの出力の下降を速くすることになり、サージングセンサーのリセットを早めることになる。サージング固有振動周期よりはるかに長い周期で繰り返されるＰＩＤ演算部の入力Ｘ_εの振動ならサージングの異常加振の危険性はかなり小さくなるので、過去の加振歴の影響はほとんど無視してよくなるが、信号選択要素２０Ｃの設定値０.２ はこの種の判断をさせるものである。リミッター２０Ｅの上限設定値２５を下げると、信号選択要素２０Ｃの設定値が同じでもサージングセンサーがリセットしやすくなるので正確には信号選択要素２０Ｃとリミッター２０Ｅの設定はセットで検討する。なお、ＰＩＤ演算部の入力Ｘ_εが同じ振幅で加振周期がサージング固有振動相当周期よりはるかに短くなってもサージングは減衰するので、サージングセンサーはＯＦＦしてもよいが、図４に示すサージングセンサーでもそのように調整することができる。なお、サージングセンサーの精度は図３を参照しながらより理論に忠実に模擬して作ればかなり高い精度が期待でき、サージングセンサーの動作範囲を必要最小限にし、ガバナの周波数応答性能の犠牲も必要最小限にできる。
【００７１】
以上述べたように、図７の時点ｔ_b においてサージングセンサーがＯＮし、図１に示すサージングセンサーの接点１９ａ，１９ｂが切換り、比例要素４ｂ（ゲインＫ_pb），積分要素５ｂ（ゲインＫ_ib）が選択され、図６に示すレコード３のようにガイドベーン（Ｙ）の動作が急に抑制され、サージングが許容レベルに自動的に抑えられる。なお、図７，図８に示すシミュレーション解析では、図８に示すレコード１のように回転速度Ｎは終始一定と仮定している。
【００７２】
なお、発明者らは上述のサージングセンサーが実機でどれほど有効に作動するかを確認するためにあるプラントを対象に非線形項を加味してシミュレーション解析を行った。その結果を要約したのが図９である。この場合、出力調整部１３からのガイドベーン開度設定信号Ｙ_a として正弦波を与えることとし、パラメータとして３種類の振幅，５種類の周期の合計１２ケースで検証している。ここで、サージングセンサーの要否の判定については、サージングセンサーを設けない無対策では予め決めた対象サージタンクの許容最高水位を超える場合を「要」，超えない場合を「不要」とした。ガイドベーン開度設定信号Ｙ_aの振幅±０.４９で周期が１００sec，４００secの２ケースを除いて、シミュレーション解析結果が「要」の場合はサージングセンサーは実際にＯＮし、「不要」の場合には実際にＯＦＦしている。例外の２ケースはサージングセンサーの簡略化による誤差であるが、誤差は安全サイドに出ており充分許容できるレベルと判断できる。なお、上述の対象のサージタンクの許容最高水位はこのプラントが電力系統と連繋運転中の値で、負荷遮断によって上乗せされる追加変動分を考慮してもサージタンクがオーバーフローしない値に設定している。
【００７３】
以上述べたように、ガバナに低い周波数応答特性を与えるための低応答設定と、より高い周波数応答特性を与えるための高応答設定を用意しておいて、サージタンクの固有振動数近辺の周波数帯域での運転では、低応答設定を使うようにしているので、水量制御手段までのガバナ自身の総合応答ゲインが低下し、水量制御手段の振幅を所望のレベルに低下できるので、ガバナへの印加信号がサージングの固有振動数相当の周波数で本来なら過大サージングが避けられそうにない振幅で加振したとしても、過大なサージングには至らない。
【００７４】
又、サージングセンサーを備えているので、過大サージングが懸念される運転条件を的確に検出できるので、低応答設定の使用範囲も必要最小限に止めることができる。すなわち、ガバナの周波数応答特性を高く維持して、速応性を重視する通常の設定を最大限に利用することができる。
【００７５】
ガバナ演算部の積分要素のゲインは、低い方のゲインは負荷遮断後の回転速度Ｎの安定性確保のための設定になっているが、このゲインを過大サージング抑制も可能なレベルに設定しておき、サージングセンサーが動作した時も負荷遮断時と同様に低い方のゲインを自動選択するようにすれば好都合である。なお、積分要素の場合には何時ゲイン切換えを行っても出力側が飛ぶことがないので切換対象としては好ましい。
【００７６】
ガバナの演算部の積分要素，比例要素の両方のゲインを高低切換可能とし、サージングセンサーが動作した時に両要素共に低ゲイン側を自動選択するようにした場合には、切換前においても、切換後においても比例要素がある分だけ自由度が高いので各状態でより好適な設定が可能になる。但し、比例要素の場合は、過渡時に切換えが行われると、出力側が飛ぶ可能性があるのでこの点を配慮して切換えを行う。
【００７７】
サージングセンサーとしては幾つかのロジックが考えられるが、あまり複雑にするのは好ましくない。そこで、速度検出信号と出力調整信号の合流点より下流側で前記流量制御手段の変位を含むガバナの状態量から簡単に演算できて、サージングの大小との相関を確認できる所定の指標を予めシミュレーション等によって見つけておく。その上で、この指標の値を刻々のガバナ状態量から計算して過大サージングを予測／検出する方法が考えられる。なお、指標を計算するには速度検出信号と出力調整信号の総合効果が問題になるので、両信号の合流点より下流側のガバナ状態量をデータとして取り込む。
【００７８】
なお、サージングセンサー用の指標を算出するためのガバナ状態量としては、定常時にゼロまたはそれに近い値に復帰する状態量を選ぶとよい。ガバナがある信号によって加振されている時を考えると、サージング（サージタンクの水位変動）に関係するのは、いずれのガバナ状態量についても変化幅で、絶対値ではないからである。
【００７９】
ガバナの状態量自身は定常時にはゼロまたはそれに近い値に復帰しないとしても、微分等所定の演算を加えて定常時にはゼロまたはそれに近い値に復帰する状態量に変換した上で指標算出に使うのは上述した点を配慮していることによる。又、サージングセンサーを適用する場合において、指標の算出のために、刻々の状態量の瞬時値だけでなく、それ以前の状態量の経歴も反映されるように、積分演算または記憶演算も含むと効果的である。同じ水量制御手段の変位、例えば、８０％開度から６０％開度への変位、を考えても、サージングの固有振動の１周期前にも１００％開度から８０％開度への変位があった場合には、前の変位によるサージングと今回の変位によるサージングが重なってサージングの変動幅は約２倍になる。また別の例で、サージングの固有振動の１／２周期前に１００％開度から８０％開度への水量制御手段の変位があった場合には、前の変位によるサージングと今回の変位によるサージングが打ち消し合ってサージングの変動幅はほとんどゼロになる。
【００８０】
別の例では、サージングの固有振動の１周期前に水量制御手段が６０％開度から８０％開度へ変位していた場合には、前の変位によるサージングと今回の変位によるサージングが打ち消し合ってサージングの変動幅はごく小さくなる。別の例では、サージングの固有振動の１／２周期前に水量制御手段が６０％開度から８０％開度へ変位していた場合には、前の変位によるサージングと今回の変位によるサージングが重なってサージング変動幅は約２倍になる。このように過去の水量制御手段の変位幅，方向，タイミングによってサージングの増幅，減衰が大きく変わるため、前述のようにサージングセンサーの指標演算ロジックに過去のデータを反映する積分要素等の記憶要素を入れた方が精度を上げることができる。しかし、精度を追求し過ぎると指標演算ロジックが難しくなり過ぎるので、実際的には、ある程度の妥協が必要である。妥協の例としては、水量制御手段に与えられる変位の方向は無視して変動幅の絶対値と頻度だけに応答するタイプの指標演算ロジックを作ってもよい。しかし、この場合、サージングセンサーが働かない方向に精度が低下するのは危険であるので、無用でも働く方向に設計するべきである。前述の例の変動幅の絶対値と頻度だけに応答するタイプの指標演算ロジックにはこのような配慮が働いている。結果としてサージングセンサーは必要以上に動作することになり、その度にガバナゲインが下げられ、周波数応答特性が低下するがこの程度は一般に充分許容できるものである。
【００８１】
なお、指標の演算に使う積分または記憶演算の効果は、入力信号のサージング加振レベルが低下すれば時間と共に減衰していくようにする。この理由は、過去の水量制御手段の変位によるサージングは時間の経過と共に減衰していくためである。
【００８２】
バンドフィルター回路を配置するのは出力調整信号回路に限られるものではなく、最終的に前記流量制御手段を制御する印加信号であれば必要に応じて同様に配置する。一般に負荷制限装置と呼ばれている一種の水量制御手段の開度上限制限装置が遠方信号で繰り返し操作される構成の場合には、負荷制限装置も対象になる。
【００８３】
図１０は本発明の別の実施例でＡＦＣ（系統の自動周波数制御）運転中のサージング抑制制御に関するものである。１３Ａはガバナの出力調整部の演算部、１３Ｂはガバナ１３Ａの前段に設けられた加算部、１３Ｃは加算部１３Ｂの前段に設けられ、電力系統全体のＡＦＣを司る遠方の制御所から当プラントに指令されるＡＦＣ指令信号Ｐ_afc が入力されるバンドフィルターであり、後述するバンドフィルター１３Ｃの出力と発電機の発電機電力Ｐ_g との偏差がとられる。５０は回転速度Ｎを入力するガバナ、１００はガバナ５０に接続されたポンプ水車、２００はポンプ水車１００に接続された発電機を示す。Ｐ_xはバンドフィルター１３Ｃの出力、Ｐ_g は発電機の実際の発電機電力を示す。
【００８４】
本実施例の説明に入る前に、プラント側で行う従来のＡＦＣ対応制御の説明を行う。ガバナ５０のは図１に示す構成からサージングセンサー２０，比例要素４ｂ，積分要素５ｂ，サージングセンサー接点１９ａ，１９ｂを削除した構成となっている。ＡＦＣ指令信号Ｐ_afc は、直接加算部１３Ｂに入力され、これに発電機電力Ｐ_g が追従するよう発電機電力Ｐ_g が加算部１３Ｂに負帰還され、演算部１３ＡはＡＦＣ指令信号Ｐ_afc と発電機電力Ｐ_g の偏差が小さくなり、最終的にゼロになるように積分等の演算を行い、ガイドベーン開度設定信号Ｙ_a を出力する。ガイドベーン開度設定信号Ｙ_a に追従してガイドベーン開度Ｙが制御され、ポンプ水車１００の出力ｐ_t が制御され、機械的出力ｐ_t は発電機２００によって発電機電力Ｐ_g に変換されて電力系統に送り出される。なお、ガバナ５０にはガイドベーン開度設定信号Ｙ_a の他に回転速度信号Ｎも入力されるが、回転速度信号Ｎについてはサージング異常加振の心配はないと想定する。
【００８５】
当然ながらＡＦＣの観点では、ＡＦＣ指令信号Ｐ_afc から発電機電力Ｐ_g までのプラント側の周波数応答特性が高い方が望ましい。他方、プラント側には周波数応答特性を上げ過ぎるとガイドベーン開度設定信号Ｙ_a の振れが大きくなり過ぎてサージングが過大になるという問題がある。そこで、本実施例では、特にバンドフィルター１３Ｃの作用について説明する。図１０に示すバンドフィルター１３Ｃの伝達関数は［(１＋Ｔ₂・Ｓ)＊(１＋Ｔ₃・Ｓ)］／［（１＋Ｔ₁・Ｓ)＊ （１＋Ｔ₄・Ｓ)］である。ここで、Ｔ₁からＴ₄は所定の時定数、Ｓはラプラス演算子である。このバンドフィルターの周波数応答特性をボード線図で示すと図１１となる。図１１で、横軸は周波数（ＨＺ）、縦軸はゲイン（ｄｂ）を示す。周波数１／(２πＴ₁）はサージング共振周波数より低くなるように時定数Ｔ₁ を設定し、また、周波数１／(２πＴ₄）はサージング共振周波数より高くなるように時定数Ｔ₄を設定する。より好ましくは、周波数１／(２πＴ₂)はサージング共振周波数より低くなるように時定数Ｔ₂を設定し、また、周波数１／(２πＴ₃)はサージング共振周波数より高くなるように時定数Ｔ₃ を設定する。このように時定数Ｔ₁，Ｔ₂，Ｔ₃，Ｔ₄を設定すれば、サージング共振周波数近辺の周波数帯域においてＡＦＣ指令信号Ｐ_afc に対するバンドフィルターＰ_x の出力の周波数応答ゲインを何十分の一にすることができる。なお、サージング異常加振はサージング共振周波数１点のみで起こるわけではなく上下にある程度の危険バンドを想定しておく必要がある。このためにはＴ₁，Ｔ₂,Ｔ₃,Ｔ₄をサージング共振周波数から所定の余裕を付けて離す必要がある。他方、このバンドフィルター１３Ｃを付ければ、１／(２πＴ₁)より低い周波数や１／(２πＴ₄)より高い周波数帯域ではサージング異常加振問題には囚われずに存分に高いゲインを設定してもよいことになる。すなわち、この帯域ではＡＦＣ応答性能を随意に上げることができる。図８に示す例では線形化モデルのバンドフィルターが示されているが、ＡＦＣ応答とサージング抑制が両立できるものであれば線形，非線形いかなるタイプでも構わない。
【００８６】
以上述べたように、本実施例では、サージタンクのサージング固有振動数に近い周波数帯域の入力に対しては、その他の周波数帯域の入力に比べてガバナの周波数応答特性が低くなるように設定したバンドフィルター回路を備えているので、サージングセンサーのような特別の判断要素を必要としない。過大サージングを引き起こす可能性のあるような信号が与えられても、ガバナの出口である水量制御手段は過度には振られないようバンドフィルターの低い方の周波数応答特性を設定するだけでよい。
【００８７】
バンドフィルター回路をガバナの出力調整信号の印加回路上で、速度検出信号との合流点より手前に配置しておけば、バンドフィルターを出力調整信号だけに作用させ、ガバナ本来の速度制御動作には支障を与えない様にすることができる。この場合には、過大サージングを引き起こす可能性のある信号を出力調整信号に限定できる場合を想定している。このような、出力調整信号の例としては、遠方制御で与えられるＡＦＣ（自動周波数制御）信号等がある。
【００８８】
バンドフィルターの具体例として、伝達関数で［（１＋Ｔ₂・Ｓ）＊（１＋Ｔ₃・Ｓ）］／［（１＋Ｔ₁・Ｓ）＊（１＋Ｔ₄・Ｓ）］（但し、Ｔ₁からＴ₄は所定の時定数、Ｓはラプラス演算子）を例として挙げたがもちろんこれに限定されるものではない。ある周波数帯域ｆ_a から周波数帯域ｆ_b の間で通常より低い周波数応答特性をもたせるようにして、サージングの固有振動数がこの周波数帯域ｆ_a と周波数帯域ｆ_b の間に入るようにしたものであれば何でもよい。
【００８９】
上述において、水量制御手段は水車やポンプ水車の発電モードではガイドベーンに相当するが、可変速揚水発電機械の揚水運転モードを考えれば、ポンプのガイドベーンというより回転速度制御手段に相当する。揚水量は回転速度を変えれば大きく変化するがガイドベーン開度を変えてもあまり変わらないためである。又、上記説明では、サージングセンサーとバンドフィルターの２つの実施例を単独使用するケースにつき説明したが、両者を併用することも可能である。
【００９０】
なお、本実施例は、次のように構成することを特徴とすることができる。すなわち、前記ガバナの演算部がゲインを高低切換可能な比例要素を備えるものであって、前記サージングセンサーが動作した時には積分要素ゲイン及び比例要素ゲインを低ゲインに自動選択する請求項３に記載のサージタンクを備えた水力プラントの水力機械。
【００９１】
前記バンドフィルター回路をガバナの出力調整信号の印加回路上で、速度検出信号との合流点より手前に配置した請求項４に記載のサージタンクを備えた水力プラントの水力機械。
【００９２】
前記サージングセンサーが、速度検出信号と出力調整信号の合流点より下流側で前記流量制御手段の変位を含むガバナの状態量のうちの特定の状態量を連続監視し、サージングの大小との相関を予め確認してある所定の指標の刻々の値を前記特定状態量から算出し、この刻々の指標の大小で過大サージングを検出するものである請求項２に記載のサージタンクを備えた水力プラントの水力機械。
【００９３】
前記特定の状態量が、定常時にはゼロまたはそれに近い値に復帰するガバナの状態量、又は定常時にはゼロまたはそれに近い値に復帰しないとしても、微分等所定の演算を加えて定常時にはゼロまたはそれに近い値に復帰する状態量に変換した上で特定の状態量の代わりに使用するものであるサージタンクを備えた水力プラントの水力機械。
【００９４】
前記演算部が、前記指標の算出に刻々の状態量の値の他それ以前の状態量の経歴も反映するための積分演算または記憶演算を含むものであるサージタンクを備えた水力プラントの水力機械。
【００９５】
前記積分または記憶演算を、入力信号のサージング加振レベルが低下した時に時間と共に減衰していくようにしたサージタンクを備えた水力プラントの水力機械。
【００９６】
前記バンドフィルター回路を最終的に前記流量制御手段を制御するガバナへの特定の印加信号の回路上に配置した請求項４に記載のサージタンクを備えた水力プラントの水力機械。
【００９７】
前記バンドフィルターの伝達関数を［（１＋Ｔ₂・Ｓ）＊（１＋Ｔ₃・Ｓ）］／［（１＋Ｔ₁・Ｓ）＊（１＋Ｔ₄・Ｓ）］または同等としサージング抑制の対象となるサージタンクの固有振動数が１／（２π・Ｔ₁）と１／（２π・Ｔ₄）の間に入るようにＴ１，Ｔ２を調整した請求項４に記載のサージタンクを備えた水力プラントの水力機械。
【００９８】
次に、特に電力系統の自動周波数制御（ＡＦＣ）等の系統制御に関係して遠方から発電機または電動機の電力の設定値を高速で調整する場合に好適な水力機械に関する実施例について説明する。
【００９９】
図２に示すように構成された水路構成では、図２に示す水力プラントの水撃を含む水車の挙動、すなわち、ガバナの出力であるガイドベーン（水量制御手段）開度Ｙを入力とするガバナの制御対象の線形化モデルは図３に示す１００Ｆをｇ／(０.２・Ｖ₂₀＋Ｌ₃・Ｖ₃₀)・Ｓに置き換えたようになる。ここで、各変数は無次元化したものであり、数１５で表すことができる。
【０１００】
ガイドベーン（水量制御手段）の開度変化ｙ→加算部１００Ａ→水撃の模擬項１００Ｂ→（ｐ_u ）単位の水撃を（ｍ）単位に変換する係数１００Ｄ→加算部１００Ｅ→管路内水柱の加速を模擬する項１００Ｆ→水車流量変化ｑと一巡する回路の総合伝達関数は時定数は(Ｌ₂・Ｖ₂₀＋Ｌ₃．Ｖ₃₀）／（２ｇ・Ｈ₀）であり、ゲイン１.０ の一次遅れ要素となる。ガイドベーン（水量制御手段）開度変化ｙ→加算部１００Ａ→水撃の模擬項１００Ｂ→有効落差変化ｈの総合伝達関数は時定数が（Ｌ₂・Ｖ₂₀＋Ｌ₃・Ｖ₃₀）／（２ｇ・Ｈ₀）でゲイン２.０の不完全微分要素となる。このことから、ガイドベーン（水量制御手段）開度変化ｙから水車出力変化ｐ_t までの総合伝達関数は(１−Ｔ_w・Ｓ）／（１＋０.５Ｔ_w・Ｓ）となる。ここで、Ｔ_w＝（Ｌ₂・Ｖ₂₀＋Ｌ₃．Ｖ₃₀）／（ｇ・Ｈ₀）としている。
【０１０１】
すなわち、ガイドベーンを開けた時には水車出力ｐ_t は最終的にはｙ相当値に増加するものの一時的には逆に減少し、反対にガイドベーンを閉じた時には水車出力ｐ_t は最終的にはｙ相当値に減少するものの一時的には逆に増加することを示している。この水車出力ｐ_t の一時的な逆応答の影響は回転速度Ｎの変化にも現れ、これがまた回転速度ガバナの入力側へと復元されてくる。従って、水力プラントが大電力系統から分離され、実質的に単独送電状態になった場合や、完全に負荷遮断された後の無負荷運転の場合には、この逆応答があっても回転速度制御系の安定性は、回転速度ガバナだけで確保する必要があり、後述する回転速度ガバナの比例ゲインＰ，積分ゲインＩを充分小さく設定する必要がある。又、回転速度ガバナの微分ゲインＤはある程度までは大きくした方が回転速度制御系の安定化に貢献するが、それを超えると逆に安定性を損なう関係になっている。
【０１０２】
図１２は、本実施例のガバナの制御ブロック図である。図１２において、５０は回転速度を入力するガバナ（電力制御部あるいは電力制御手段ともいう）、
１００はガバナ５０に接続されたポンプ水車、２００はポンプ水車１００に接続された発電機または電動機を示す。
【０１０３】
回転速度ガバナ５０のブロック線図は図１５に示すようになっている。１はポンプ水車１００の回転速度Ｎを検出する速度検出部、Ｘ_n は速度検出部１で検出された速度検出信号、２は回転速度の基準値を設定する速度調整部、ｘ₀ は速度調整部２から出力される設定値、３は設定値ｘ₀ と速度検出信号Ｘ_n と後述する速度調定率設定部からの復元信号Ｘ_σとの加算器、Ｘ_εは加算器３で算出された信号ですぐ下流のＰＩＤ演算回路の入力信号、２０は上流側サージタンク用サージングセンサー、４は比例演算要素（Ｐ要素）、５は積分演算要素（Ｉ要素）、６は微分演算要素（Ｄ要素）を示し、その出力信号Ｚ_d ，比例演算要素の出力信号Ｚ_p ，積分演算要素の出力信号Ｚ_i は、加算部７で加算される。この比例演算要素の出力信号Ｚ_p ，積分演算要素の出力信号Ｚ_i ，微分演算要素の出力信号Ｚ_d を総合した信号は、ガイドベーン開度指令Ｚであり、このガイドベーン開度指令Ｚに実際のガイドベーン開度Ｙがフィードバックされ、加算部８で偏差がとられる。この偏差信号Ｙ_{ε 1} は、リミッター９を介して油圧サーボモータ１０に入力される。リミッター９のθ_R はガイドベーンの開速度をθ_R・Ｃ_yに、θ_L は閉速度をθ_l・Ｃ_y に制限するためのものであり、リミッター９の出力信号Ｙ_{ε 2}は偏差信号Ｙ_{ε 1} を上記開閉速度制限を考慮して制限した信号となっている。油圧サーボモータ１０は一種の油圧増幅器になっており、伝達関数では一次遅れ要素を構成し、ガイドベーン開度指令ｚを増幅して充分なストロークと操作力をもつガイドベーン開度Ｙに変換し、水量制御手段であるガイドベーンを直接操作する。
【０１０４】
実際のガイドベーン開度Ｙはフィードバックされ、加算部１１で、出力調整部１３からのガイドベーン開度設定信号Ｙ_a との偏差が与えられる。もし実際のガイドベーン開度Ｙがガイドベーン開度設定信号Ｙ_a に達していない場合、すなわち、Ｙ＜Ｙ_a の場合にはその差がゼロになるまでガバナのＰＩＤ演算部に開信号σ(Ｙ_a−Ｙ）が送り続けられるので、やがてはＹ＝Ｙ_a となりその段階で落ち着く。開信号σは速度調定率設定部１２で設定され、復元信号Ｘ_σを出力する。この開信号σは速度検出信号Ｘ_n の変化に対するガイドベーン開度Ｙの変化の割合を決めるゲインで、一般には電力系統の中でのプラントの役割を考慮して一度決めたら変更されないものである。
【０１０５】
ところで図１５に示すガバナには外部から与えられる信号として、発電機に与えられる外部負荷Ｌと出力調整部１３から与えられるガイドベーン開度設定信号Ｙ_a の２つの信号がある。外部負荷Ｌは、その変動によって回転速度Ｘ_n の速度変動を生じさせる。一方、出力調整部１３に入力される信号の代表的なものが
ＡＦＣ（自動周波数制御）であり、ＡＦＣの場合には専ら電力系統の周波数制御の観点で出される指令であるので、サージング異常加振等の水力プラントの特殊事情は感知せずに出され、図示してない遠方の中央制御所から遠隔操作で与えられる。
【０１０６】
図１２に示すＡＦＣ制御系の構成は次のようになっている。出力調整部１３がＡＦＣによって遠方から制御されるが、ここでは、電力の手動操作のための上げ，下げ指令も受けられる例を示す。Ｐ_afc はＡＦＣ指令信号でＡＦＣが要求する電力値を、Ｐ_g は実際の発電機電力を示し、１３Ｃは両者の偏差、すなわち電力偏差Ｐ_{ε 1}を求める比較部を示す。電力偏差Ｐ_{ε 1}は加算部１３Ｂで手動操作のための上げ，下げ指令と加算され合成入力信号Ｐ_{ε 1} となり、電力偏差積分器13Ａ（積分演算手段ともいう）に入力される。ここで、電力偏差積分器１３Ａは純粋の積分としているが近似的に積分とみなせるものも含んでいる。例えば、電力偏差Ｐ_{ε 1} に応じて＋１／ＯＦＦ／−１パルス列を作りこれを積分演算するタイプとし、パルス列のＯＦＦ時間を電力偏差Ｐ_{ε 1} に応じて調整するものもある。電力偏差積分器１３Ａと並列に比例要素１３Ｄ(並列演算器ともいう)が設けられており、この比例要素１３Ｄの出力を電力偏差積分器１３Ａの出力に加算部１３Ｅで加算する。このようにすることにより、電力偏差Ｐ_{ε 1} の演算がＩ演算からＰＩ演算となり応答性が大きく改善できる。加算部１３Ｅの出力Ｙ_a は図８で詳細に説明した回転速度ガバナ５０に入力される。なお、ポンプ水車１００は入力であるガイドベーン開度Ｙに応じて水車出力Ｐ_t を発生させる。２００は電力系統と連繋運転中の同期発電機を示し、ここで機械的な水車出力Ｐ_t が電気的出力すなわち発電機の発電機電力Ｐ_g 変換される。
【０１０７】
電力偏差積分器１３Ａは手動操作のための上げパルス信号がある間はガイドベーン開度設定信号Ｙ_aを毎秒Ｋ_{i θ} の速度で上げ続け、下げパルス信号がある間はガイドベーン開度設定信号Ｙ_a を毎秒Ｋ_{i θ} の速度でＹ_a を下げ続ける。パルス信号がなくなればガイドベーン開度設定信号Ｙ_a の上げ下げを停止する。ところで速度Ｋ_{i θ}が大き過ぎるとガイドベーン開度設定信号Ｙ_aが速く走行し過ぎて所望の値に正確に止められず手動調整が難しくなるので、速度Ｋ_{i θ} は一般に１(ｐ_u)／５０sec〜１(ｐ_u）／６０secに設定される。
【０１０８】
回転速度Ｎ，ガイドベーン開度設定信号Ｙ_a いずれの変化によっても水車の上流側，下流側いずれのサージタンクも異常加振される可能性があるが、ここでは上流側サージタンクを中心に説明する。
【０１０９】
図１６，図１７は図１５において出力調整部１３の出力、すなわちガイドベーン開度設定信号Ｙ_a を正弦波状に変化させた場合の上流側サージタンクの応答例を示すボード線図である。図１６は回転速度ガバナの比例ゲインＫ_p ，積分ゲインＫ_i を比較的大きく設定したケース、図１７は回転速度ガバナの比例ゲインＫ_p，積分ゲインＫ_iを比較的小さく設定したケースを示す。この場合、上流側サージタンクの固有振動数は０.００４７４Ｈｚで、いずれのケースも0.00474Ｈｚ付近で上流側サージタンク水位ｈ_fuの応答ゲインが急激に立ち上がっている。なお、上流側サージタンクの固有振動数における応答ゲインのピーク値は、図１６の方が２４.４(ｄｂ)で、図１７の７.６(ｄｂ)より高く、この差１６.８(ｄｂ）は６.９ 倍に相当する。図１６の設定でも上サージタンクがオーバーフローしなければ問題ないが、オーバーフローの可能性があればピーク値を下げるため対策が必要である。すなわち、入力であるガイドベーン開度設定信号Ｙ_a の振幅を制限するか、比例ゲインＫ_p 、積分ゲインＫ_i を下げる対策が必要になる。
【０１１０】
以下の説明では、上流側サージタンクの固有振動数における応答ゲインのピーク値の許容最大値は図１７に示す７.６(ｄｂ）相当と仮定する。図１８は、比例要素１３Ｄを設けない場合のＡＦＣの周波数応答特性、すなわち、ＡＦＣ指令Ｐ_afc に対する水車出力Ｐ_t の応答性能を示す。なお、水車出力Ｐ_t と発電機電力Ｐ_g の間にはほとんど遅れがないので、ＡＦＣ指令Ｐ_afc に対する発電機電力Ｐ_gの応答性能としてもよい。なお、この場合回転速度ガバナの比例ゲインＫ_p，積分ゲインＫ_i は図１７に示すものと同じに設定している。このように比例要素１３Ｄを設けない場合には、約０.０１Ｈｚ 以上ではＡＦＣ応答ゲインは１／１００以下に大きく低下してしまい、約０.０１Ｈｚ 以上でＡＦＣ応答は期待できない。
【０１１１】
図２０は本実施例のＡＦＣ運転時の電力の周波数応答特性を示す。並列回路として比例要素１３Ｄを設け、ゲインＫ_{p θ}を１.０にしているので、図１８に示す周波数応答特性に対し、特に０.０１Ｈｚ 以上の周波数帯における特性が大きく改善されることが解る。
【０１１２】
図１９は本実施例のＡＦＣ運転時の上流側サージタンク水位応答のボード線図である。条件は図２０に示すものと同じである。図１９から分かるように、AFC応答の改善に伴って上流側サージタンクのサージングも拡大している。
【０１１３】
以上説明したように、電力指令に対する一巡制御系の電力偏差積分演算器と並列に電力偏差積分演算器と同じ電力偏差信号を入力とする並列演算手段を設け、電力偏差がある過渡時に限って電力偏差積分演算器の応答を高めるような信号を出力させるようにしているので、定常的には(遠方からの電力指令＝実際の電力)の関係を保持しながらも過渡的には応答の遅れを的確に補償することができる。特に、電力偏差積分演算器の出力と並列演算手段の出力を加算した和信号を回転速度制御系の回転速度ガバナ演算部に一種のバイアス信号として印加する構成の場合には、並列演算手段が回転速度制御ループの外にあるので、回転速度制御系の一巡伝達関数に影響を与えることなく遠方からの電力指令に対する電力応答を自由に改善することができる。また、電力偏差積分演算器が電力の手動操作のための上げ，下げ指令も受けられるように充分低いゲインになっていたとしても、電力偏差積分演算器をバイパスして遠方からの電力指令に対する電力応答ゲインを自由に上げることができる。
【０１１４】
又、並列演算手段として比例演算を設けることによって電力偏差積分器だけの単純なＩ演算からＰ＋Ｉ（比例＋積分）演算に置き換えることができ、周波数応答で言えばゲイン低下や位相遅れの補償が自在にできるようになり、遠方からの電力指令に対する電力制御系の応答をより的確に適正化することが可能になる。又、並列演算手段に比例演算＋微分演算を設けることによって電力偏差積分器だけの単純なＩ演算からＰ＋Ｉ＋Ｄ（比例＋積分＋微分）演算に置き換えることができ、遠方からの電力指令に対する電力制御の周波数応答特性を一層的確に改善することができ適正化が可能になる。回転速度ガバナ演算部より下流の回転速度制御系側の特殊事情、例えば回転速度ガバナのＰＩＤゲインを自由に上げることはできない等の事情にも拘わらずより的確に適正化が可能になる。
【０１１５】
図１３は本発明の他の実施例のＡＦＣ制御系を示す。本実施例は図１２に示す実施例と同様に構成されているが、本実施例では、ＡＦＣ入力の受信部にバンドフィルター１３Ｆを設けている。なお、図１４は図１３に示すバンドフィルター部の周波数応答特性を示す。すなわち、バンドフィルター１３Ｆ単独の周波数応答特性を示すボード線図である。このバンドフィルターでは、応答ゲインが１／(２πＴ₁)(Ｈｚ）から低下し始め、１／(２πＴ₂)(Ｈｚ)〜１／(２πＴ₃)(Ｈｚ)の範囲で最低になり、１／(２πＴ₃)(Ｈｚ)から再び上昇を始め、１／(２πＴ₄)（Ｈｚ）で元のレベルに戻るようになっている。そして、上流側サージタンクの固有振動数0.00474(Ｈｚ）が１／（２πＴ₂)(Ｈｚ）〜１／（２πＴ₃)(Ｈｚ）の周波数帯に入るように時定数Ｔ₂ ，Ｔ₃ を設定している。なお、上流側サージタンクの固有振動数がバンドフィルターの低ゲイン部に正確に入らなくても１／ （２πＴ₁)(Ｈｚ）から１／（２πＴ₄)(Ｈｚ）の間に入るようにしておけば効率的ではないが効果が期待できる。
【０１１６】
図２２は本実施例のＡＦＣ運転時の電力応答のボード線図である。条件は0.00474Ｈｚが１／（２πＴ₂)(Ｈｚ)〜１／（２πＴ₃)(Ｈｚ）の周波数帯に入るように設定したバンドフィルターを設けたこととＫ_{i θ}を１／１０ に下げた以外は、図２０に示すものと変わらない設定としている。この結果、0.00474Ｈｚ 前後の電力応答が若干低下したが０.１Ｈｚ以上では全く影響が出ていない。
【０１１７】
図１９は本実施例のＡＦＣ運転時の上サージタンク水位応答のボード線図で、条件は図２０のものと同じ設定である。上流側サージタンクの固有振動数 0.00474Ｈｚにおけるピーク値は０.８９(ｄｂ）で、図１９に示す２４.２(ｄｂ)より大幅に低下している。また、上述したオーバーフロー判定レベルである7.6 （ｄｂ）を大幅に下回っている。上述した例では、バンドフィルターとして線形モデル［(１＋Ｔ₂・Ｓ)＊(１＋Ｔ₃・Ｓ)］／［(１＋Ｔ₁・Ｓ)＊(１＋Ｔ₄・Ｓ)］を例にして説明したが、最終的にサージング共振周波数近傍でサージングの周波数応答ゲインを下げる効果を発揮するものであれば何でもよい。
【０１１８】
又、上流側，下流側サージタンクの水位変動だけを共振のポテンシャルとして説明してきたが、回転速度ガバナ自身及びその制御対象について同様の共振ポテンシャルがある場合にはその個々について同様の対策を講じればよい。
【０１１９】
以上説明したように、本実施例によれば、遠方指令受信部にバンドフィルターを設けているので、たとえ前述の電力制御応答対策の結果、サージタンクのサージング共振等特定の周波数帯での異常加振の可能性が出てきてもその特定周波数帯だけの電力制御応答を的確に下げ問題を回避することができ、その他の危険性のない周波数帯では電力制御応答を一杯に上げることが可能になる。
【０１２０】
遠方電力制御用にＰ＋Ｉ＋Ｄ演算を採用し、遠方指令受信部にバンドフィルターを採用した場合は、遠方電力制御用にＰ＋Ｉ演算を採用し、遠方指令受信部にバンドフィルターを採用した場合より、より木目細かな調整ができる。
【０１２１】
なお、バンドフィルターの伝達関数を［(１＋Ｔ₂・Ｓ)＊(１＋Ｔ₃・Ｓ)］／ ［(１＋Ｔ₁・Ｓ)＊(１＋Ｔ₄・Ｓ)］（但し、Ｔ₁ からＴ₄ は所定の時定数、Ｓはラプラス演算子でＴ₁ ＜Ｔ₂ ＜Ｔ₃ ＜Ｔ₄ ）とすれば、周波数応答特性を１／ (２π・Ｔ₁)から１／(２π・Ｔ₄)の周波数帯に限って下げることができるのでサージング共振周波数等制御対象側の共振が予想される特定の周波数帯がこの範囲に入るようにＴ₁，Ｔ₄を調整すれば共振を的確に防止できる。
【０１２２】
又、このフィルターの周波数応答特性は１／(２π・Ｔ₂)と１／(２π・Ｔ₃)の間で底になるので共振が予想される特定の周波数帯がこの間に入るようにＴ₂ ，Ｔ₃ を調整すれば一層好ましい。
【０１２３】
バンドフィルターは上記した例に限定されるものではなく、ある周波数帯域ｆ_a からｆ_b の間で通常より低い周波数応答特性をもたせるようにし、共振が予想される特定の周波数帯がこの周波数ｆ_a と周波数ｆ_b の間に入るようにしたものであればよい。
【０１２４】
なお、本実施例では、次のように構成することを特徴とすることができる。すなわち、ランナーを有する水車と、該ランナーに機械的に直結され電力系統と電気的に接続された発電機または電動機と、該発電機の出力または該電動機の入力を制御する電力制御手段と、電力の上げ，下げ操作指令を手動で与える手動操作指令手段と、遠方からの電力の要求値を与える遠方指令手段と、実際の電力値を復元する電力復元手段と、該遠方指令手段からの要求値と電力復元手段からの実際の電力値の偏差を求める偏差導出手段と、該偏差導出手段から出力される電力偏差信号と前記手動操作指令手段からの指令に応じて目視確認に好適な速度で走行し該電力制御手段に対して電力の上げ，下げ指令信号とを入力する積分または同等の演算を行う積分形電力指令演算手段を備え、遠方からの電力制御の場合には、前記偏差導出手段→積分形電力指令演算手段→水車および発電機／電動機→電力復元手段の負帰還回路が構成されるようにしたものであって、前記電力偏差信号を入力し、前記積分形電力指令演算手段と並列に配置されその出力で前記積分形電力指令演算手段の出力を補正するようにした並列演算手段を設け、該並列演算手段は電力偏差がある過渡時には該積分形電力指令演算手段の応答を高めるような信号を出力し、定常状態に戻ればその出力をゼロまたは略ゼロに戻すようにしたことを特徴とする水力機械。
【０１２５】
前記並列演算器が比例演算要素と微分演算要素を直列に接続されたものである請求項５から８のいずれかに記載の水力機械。
【０１２６】
前記演算部が目視確認に好適な速度で走行し手動で与える電力の上げ，下げ指令信号を入力するものである請求項５から８のいずれかに記載の水力機械。
【０１２７】
前記演算器が前記比較部から出力される電力偏差信号がある間は、前記電力制御部に対し前記該電力偏差を減少させるように作用する出力信号を増やし続けるものである請求項５から８のいずれかに記載の水力機械。
【０１２８】
前記比較部もしくは偏差導出手段の前段に設けられ、前記遠方からの電力の要求値を入力するバンドフィルターを備えたものであって、該バンドフィルターの応答ゲインが特定の周波数帯の変動入力に対しては他の周波数帯の変動入力に比べて低下するものである請求項５から８のいずれかに記載の水力機械。
【０１２９】
前記演算器の特性が電力偏差がある過渡時には応答を高めるような信号を出力し、定常状態に戻ればその出力をゼロまたは略ゼロに戻すものである請求項５、又は８に記載の水力機械。
【０１３０】
Ｔ₁，Ｔ₂，Ｔ₃，Ｔ₄を所定の時定数でＴ₁＜Ｔ₂＜Ｔ₃＜Ｔ₄、Ｓをラプラス演算子とした時、前記バンドフィルターの伝達関数を［(１＋Ｔ₂・Ｓ)＊(１＋Ｔ₃・Ｓ)］／［(１＋Ｔ₁・Ｓ)＊(１＋Ｔ₄・Ｓ)］または同等とし、共振の可能性のある特定の周波数帯が１／(２π・Ｔ₁)と１／(２π・Ｔ₄)の間に入るようにＴ₁，Ｔ₄を設定した水力機械。
【０１３１】
【発明の効果】
本発明によれば、サージングの異常加振を自動的に防止できるという保証ができるので、安全を損なうことなく、上下流水路に設置されるサージタンクの容量（具体的には横断面積や高さ）を大幅に低減し土木コスト低減を計ることができる。しかも、サージングセンサー方式にしても、バンドフィルター方式にしてもガバナを大幅に変更することなく達成でき、このためのコストアップは効果から比べれば無視できるものである。バンドフィルターを活用することによってサージングと矛盾しない形でＡＦＣ等のガバナ応答特性を大幅に改善することができる。
【０１３２】
又、回転速度制御系と遠方指令に応答する電力制御系の両方が最終的には同一の操作端を制御するケースでも、遠方指令に応答する電力制御系の応答性を回転速度制御系の応答性能、特に安定性を損なうことなく合理的に適正化でき、特に応答ゲインを大幅に改善することができる。
【０１３３】
また、電力の手動操作のための上げ，下げ指令も電力偏差積分演算器で受ける場合のように電力偏差積分のゲインが充分高くできない場合でも、遠方指令に対する電力制御系の応答性を自在に上げることができる。
【０１３４】
また、上下流水路のサージタンクのサージング等特定の周波数帯での異常加振現象を合理的に防止することができ、その他の周波数帯では一巡制御系の応答性を最大限に保持することができる。
【図面の簡単な説明】
【図１】本発明の一実施例であるガバナのブロック線図である。
【図２】上下水路の両方にサージタンクを有する水力プラントの水路構成図である。
【図３】ガバナの制御対象の線形化モデルを示すブロック図である。
【図４】図３に示す上サージングタンクのブロック図である。
【図５】図３に示す下サージングタンクのブロック図である。
【図６】サージングセンサーの一例を示す構成図である。
【図７】サージングセンサーの動作を説明する図である。
【図８】サージングセンサーの動作を説明する図である。
【図９】サージングセンサーの検出精度の評価の解析例を示す図である。
【図１０】バンドフィルターの例を示すブロック図である。
【図１１】図１０に示すバンドフィルターの周波数応答特性を示すボード線図である。
【図１２】本発明の他の実施例のＡＦＣ制御系の構成を示す図である。
【図１３】本発明の他の実施例のＡＦＣ制御系の構成を示す図である。
【図１４】図１３のバンドフィルター部の周波数応答特性を示す図である。
【図１５】回転速度ガバナのブロック線図である。
【図１６】図１５においてＹ_a を正弦波状に変化させた場合のサージタンクの応答を示すボード線図である。
【図１７】図１５においてＹ_a を正弦波状に変化させた場合のサージタンクの応答を示すボード線図である。
【図１８】図１５の並列回路を設けない場合のＡＦＣの周波数応答特性を示す図である。
【図１９】図１２の実施例のＡＦＣ運転時の上サージタンク水位応答のボード線図である。
【図２０】図１２の実施例のＡＦＣ運転時の電力の周波数応答特性を示す図である。
【図２１】図１３の実施例のＡＦＣ運転時の上サージタンク水位応答のボード線図である。
【図２２】図１３の実施例のＡＦＣ運転時の電力応答のボード線図である。
【符号の説明】
１…速度検出部、２…速度調整部、３…加算器、４，４ａ，４ｂ…比例演算要素、５，５ａ，５ｂ…積分演算要素、６…微分演算要素、７，８，１１…加算部、９…リミッタ−、１０…油圧サーボモータ、１２…速度調定率設定部、１３…出力調整部、１４…ブロック線図、１６…算出部、１７ａ，１７ｂ…演算部、
２０…サージングセンサ、１００…ポンプ水車、１０１…導水路、１０２…水圧鉄管、１０３…吸出管、１０４…放水路、１０５…上池、１０６…上流側サージタンク、１０７…下流側サージタンク、１０８…下池。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydraulic machine installed in a hydraulic plant having a surge tank upstream or downstream and having a water amount control means and a governor for controlling the water amount control means, and particularly suitable for rationalizing the capacity of the surge tank. Related to a hydraulic machine.
[0002]
[Prior art]
In conventional hydroelectric power generators connected to the power grid, a strong rotational speed stabilization effect can be expected from the grid when operating in conjunction with the grid, so the set value of the governor that controls the rotational speed is stable. If the speed is set to a relatively high gain with emphasis on speed response rather than performance, and if it is separated from the system or is practically separated from the system and rotation speed stabilization cannot be expected from the system side, the rotational speed is A relatively low gain is set with emphasis on stability. Therefore, conventionally, the gain of the governor is assumed to be the highest possible gain during continuous operation, and the water volume control means is opened and closed as many times as possible with a possible maximum amplitude and a period equivalent to the surge tank natural vibration. Assuming that such a signal was given to the governor, the upstream and downstream surge tanks were still designed with sufficient capacity so as not to overflow.
[0003]
Moreover, what analyzed the waterway system of a hydroelectric power station has a thing of Hitachi review VOL.56 No.12 (1974-12) p1155-1160. This document analyzes the water hammer effect of a water channel system in consideration of nonlinearity.
[0004]
Further, in a hydropower plant comprising a generator connected to an electric power system, which is a conventional device, and a turbine connected directly thereto, the turbine is generally equipped with a rotation speed detector in response to the output signal of the rotation speed detector. Control the flow rate control means (eg guide vanes) to increase the turbine output and increase it compared to the generator load to increase the rotational speed, or decrease the turbine output to reduce it compared to the generator load. The rotation speed governor is provided to reduce the rotation speed and control the rotation speed to a predetermined value, but the rotation speed → rotation speed detector → rotation speed governor calculation unit → rotation speed governor amplification unit → flow rate control means → turbine output → For a rotational speed control system that makes a round of correction with a difference from the generator load → rotational speed correction, a part for performing a kind of bias adjustment is provided in the arithmetic section of the rotational speed governor. When the hydropower plant is disconnected from the large power system and becomes substantially single transmission or complete no-load operation that supplies power only to a specific small load, the generator load is considered constant, This adjustment of the bias results in a role of speed adjustment. That is, since the turbine output corresponding to the generator load does not change, the bias adjustment can be offset by the change in the rotational speed N.
[0005]
On the other hand, when the hydropower plant is synchronously connected to the high power system, the rotation speed is fixed at the power system equivalent value, so that the bias adjustment plays a role of output adjustment. That is, the adjustment of the bias changes the opening of the flow rate control means and the turbine output, but the rotational speed does not change, so the generator load immediately follows the turbine output. In this case, the bias plays the role of adjusting the output of the turbine wheel → adjusting the power.
[0006]
By the way, when a hydropower plant is connected to a large power system, a distribution command is issued to each plant under jurisdiction for power supply and demand adjustment control of the entire power system and frequency adjustment control such as AFC. An output adjustment command that is a required value of electric power may be issued from a central control station far from the plant. However, the conventional hydroelectric power plant has a problem that the response to the remote command is extremely slow, and the contribution of the hydroelectric power plant is too low in terms of system control.
[0007]
In the prior art, the deviation signal is calculated by comparing the remote command and the actual generator power separately detected on the governor side, and the result of integrating the deviation signal is given to the rotational speed control system as a kind of bias signal. It was. More specifically, the bias signal is supplied to an output adjusting unit called 65P. However, according to the analysis results of the inventors, even if the gain of the integral calculation is increased to the allowable limit, the distance command → deviation derivation with the actual power → deviation integral calculation (hereinafter referred to as power deviation integration) → governor calculation unit Bias adjustment (ie, 65P adjustment) → Opening adjustment of flow control means → Adjustment of turbine output → Adjustment of actual power of generator There is a fatal problem and it turns out that drastic response improvement cannot be expected did.
[0008]
One reason is that the PID calculation gain of the governor calculation unit is too low. However, the PID calculation gain of the governor calculation unit is not limited to the stability of the rotational speed control system even if the hydropower plant is disconnected from the large power system and is substantially in a single power transmission state. Since there is a need to prevent damage, it cannot be raised arbitrarily. As a method for solving this, a method is considered in which the PID calculation gain of the governor calculation unit is set to a desired height during operation linked to the large power system, and is automatically switched to a low value when shifting to single power transmission. However, considering the complexity of the configuration of the power system, it cannot be adopted unless it can be detected with sufficient reliability (in practice). Further, in the one-round control circuit for the remote command, the transfer function between the opening degree adjustment of the flow rate control means and the turbine output adjustment is (1-T_w・ S) / (1 + 0.5T_wSince the backward response component of the output due to water hammer is included as expressed by S), it also has a direct adverse effect on the one-round control circuit for the remote command. Where T_w= ΣL_i・ V_i/ (G · H), L_iIs the length of the upstream and downstream channels, V_iIs the average flow velocity in the upstream and downstream channels, g is the acceleration of gravity, H is the effective head, and S is the Laplace operator.
[0009]
By the way, the PID gain of the governor calculation unit is: rotation speed → rotation speed detector → rotation speed governor calculation unit → rotation speed governor amplification unit → flow rate control means → turbine output → correction of difference with generator load → rotation speed correction and one cycle. It is set in consideration of the stability and speed response of the rotational speed control system, and the operation unit dedicated to the one-round control circuit for power control with respect to a remote command is configured so that it can be set appropriately simply by having power deviation integration calculation. Not. In addition, it is common for the power deviation integration calculator to receive an increase / decrease command for manual operation of power, and in this case, adjustment is made while visually checking, so the power deviation integral gain is naturally low. I cannot help raising it.
[0010]
In a conventional hydropower plant operating at a substantially constant speed during operation linked to the power system, both the rotational speed control system and the power control system responding to the remote command ultimately control the same operating end. . As described above, in the conventional technology, even for the one-round control system of the power for the remote command, appropriate delay compensation and gain regardless of the influence of the low PID calculation gain of the rotational speed control system and the obstruction factors such as the reverse response of water hammer. There is no example of providing a calculation unit capable of performing compensation.
[0011]
In the apparatus described in Japanese Patent Laid-Open No. 7-279814, a method is disclosed in which the far command itself is temporarily expanded and then input as one bias signal of the rotational speed control system.
[0012]
[Problems to be solved by the invention]
Conventional equipment does not consider reducing the capacity of the surge tank. Increasing the capacity of the surge tank means an increase in the excavation volume of the rock mass in the case of an underground power plant, and an increase in civil engineering costs is a heavy burden. It has become. For example, even if the height of the surge tank is increased by only 1 m, the cross-sectional area of the surge tank is tens of times the cross-sectional area of each water turbine, and the excavation volume becomes enormous.
[0013]
Moreover, if measures are taken to temporarily expand the command itself at the power command receiving unit from a distance, as in the device described in Japanese Patent Laid-Open No. 7-279814, the response of the one-round control system will be reduced to some extent. There is a possibility of compensation. However, this method is based on the idea that if the gain becomes 1/10 in the one-round control system, the gain is set to 10 × (1/10) = 1 and the gain is 1, but the frequency characteristic of the one-round control system. The response gain varies greatly according to the frequency of the signal, and there are some 1/100 and some close to 1, so this is not as simple as this. After all, there is a limit to how to compensate only outside the one-round control system, and at least accuracy degradation and inefficiency are unavoidable, so they are not efficient and impractical.
[0014]
In addition, even if the conventional technology succeeds in improving the responsiveness of the one-round control system to the power command, abnormal excitation in a specific frequency band such as surging of surge tanks in the upstream and downstream waterways may occur depending on the construction conditions of the hydraulic machine. It often caused new problems to occur. As countermeasures, there were only measures to increase the capacity of the surge tank or to give up improving the response of the one-round control system.
[0015]
The first object of the present invention is to make the governor itself intelligent and prevent excessive surging automatically even if the governor applied signal that is the design condition of the surge tank is the same. The purpose is to provide a hydraulic machine for a hydraulic power plant equipped with a surge tank that achieves a great economic effect of rationalization of design and contributes to reducing the construction cost of the hydraulic power plant.
[0016]
The second object of the present invention is to make the governor intelligent so that the vibration amplitude of the water amount control means, which is the output of the governor, is automatically suppressed to a desired level even when the surge tank is vibrated at a period equivalent to the natural vibration of the surge tank. Another object of the present invention is to provide a hydraulic machine for a hydraulic power plant equipped with a surge tank.
[0017]
A third object of the present invention is to provide a power control system that responds to a remote command even when both the rotational speed control system and the power control system that responds to a remote command ultimately control the same operating end. An object of the present invention is to provide a hydraulic machine capable of rationally optimizing the responsiveness without impairing the response performance of the rotational speed control system, in particular the stability, and greatly improving the response gain.
[0018]
The fourth object of the present invention is to control the power for the far command even when the power deviation integral gain is not sufficiently high, as in the case where the power deviation integral calculator also receives an increase / decrease command for manual operation of power. The object is to provide a hydraulic machine that can freely increase the responsiveness of the system.
[0019]
The fifth object of the present invention is to rationally prevent abnormal vibration phenomena in specific frequency bands such as surging of surge tanks in upstream and downstream water channels, and to maximize the response of the loop control system in other frequency bands. It is to provide a hydraulic machine that can be held.
[0020]
[Means for Solving the Problems]
In order to achieve the above object, a hydraulic power plant of a hydraulic plant equipped with a surge tank of the present invention comprises a movable flow rate control means, a governor for controlling the flow rate control means, and a surge tank in an upstream or downstream pipe line. A hydraulic machine installed in a hydropower plant, wherein the governor has a low response setting for giving a low frequency response characteristic to an input signal in a frequency band near the natural frequency of the surge tank, and other frequency regions It is characterized by having a high response setting for giving a higher frequency response characteristic to the input signal.
[0021]
Further, a surging sensor for detecting excessive surging or a precursor thereof is provided, and the governor automatically selects the low response setting on the condition that the surging sensor is operated.
[0022]
Hydropower installed in a hydropower plant equipped with a movable flow rate control means, a governor for controlling the flow rate control means, a surge tank in the upstream or downstream pipeline, and a surging sensor for detecting excessive surging or a precursor phenomenon thereof The governor is configured such that the calculation unit of the governor is configured so that the integral element gain can be switched between high and low, and the low gain side is automatically selected when the surging sensor operates.
[0023]
Hydropower installed in a hydropower plant having a movable flow rate control means, a governor for controlling the flow rate control means, a surge tank in the upstream or downstream pipeline, and a band filter circuit in which the frequency response characteristics of the governor are set. The frequency response characteristic of the governor is lower than the input of other frequency bands for the input of the frequency band where the frequency response characteristic of the band filter circuit is close to the surging natural frequency of the surge tank. It is set so that it may become.
[0024]
In order to achieve the above object, the hydraulic machine of the present invention is arranged in parallel with the power deviation integration calculator of the one-round control system for the power command, and corrects the output of the power deviation integration calculator with the output. The parallel calculation means inputs the same power deviation signal as the power deviation integration calculator, but outputs a signal that enhances the response of the power deviation integration calculator when there is a power deviation, When the steady state is restored, the output is set to zero or substantially zero.
[0025]
Further, the parallel calculation means performs a proportional calculation, and a P + I (proportional + integral) calculation element is inserted instead of the power deviation integration calculator. This P + I calculation element is used to optimize the response of the power control system to the power command.
[0026]
Further, the parallel calculation means performs proportional calculation + differential calculation, and puts a P + I + D (proportional + integral + differential) calculation element in place of the power deviation integration calculator. This P + I + D computing element is used to optimize the response of the power control system to the power command.
[0027]
In addition, the remote command receiving unit is provided with a band filter that reduces the response gain with respect to the fluctuation input in a specific frequency band as compared with the fluctuation input in another frequency band. In addition, the power deviation integration calculator is replaced with a P + I calculation element or a P + I + D calculation element, and a band filter provided in a remote command receiving unit is combined.
[0028]
As an example of a band filter, a transfer function [[1 + T₂・ S) * (1 + T_Three・ S)] / [(1 + T₁・ S) * (1 + T_Four・ S)] or equivalent (however, T₁To T_FourIs a predetermined time constant, S is a Laplace operator, and T₁<T₂<T_Three<T_Four) And the specific frequency band that is expected to resonate on the controlled object side such as the surging resonance frequency is₁) And 1 / (2π · T_Four) T₁, T_FourIs to adjust. More preferably 1 / (2π · T₂) And 1 / (2π · T_Three) T₂, T_ThreeIs to adjust.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 2 shows a water channel configuration of a hydropower plant having surge tanks in both the upper and lower water channels. 105 is an upper pond, 101 is a water conduit of the upper pond 105, 106 is an upstream surge tank provided in the water conduit 101, 102 is a hydraulic iron pipe connected to the upstream surge tank 106, and 100 is connected to a hydraulic iron pipe 102. The pump water turbine 103 is a suction pipe connected to the pump water turbine 100, 107 is a downstream surge tank provided in the suction pipe 103, and 104 is a water discharge channel connected to the downstream surge tank 107. In FIG. 2, H_fuIs the upstream surge tank water level measured with reference to the center of the pump turbine 100, H_fLIs the downstream surge tank water level measured from the center of the pump turbine 100, △ H_fuIs the difference between the water level in the upstream surge tank 106 and the water level in the upper pond 105, ΔH_fLIs the difference between the water level in the downstream surge tank 107 and the water level in the lower pond 108, A_fuIs the cross-sectional area of the upstream surge tank 106, A_fLIs the cross-sectional area of the downstream surge tank 107, L₁, A₁, V₁Are the length of the water conduit 101, the pipe cross-sectional area, the flow velocity, L₂, A₂, V₂Are the length of the hydraulic iron pipe 102, the pipe cross-sectional area, the flow velocity, L_Three, A_Three, V_ThreeAre the length of the suction pipe 103, the pipe cross-sectional area, the flow velocity, and L_Four, A_Four, V_FourIndicates the length of the discharge channel 104, the cross-sectional area of the pipe, and the flow velocity, respectively.
[0030]
The behavior of the water wheel including the water hammer of the hydropower plant configured as shown in FIG. 2, that is, the behavior of the control object of the governor that receives the opening degree Y of the guide vane (also referred to as water amount control means) that is the output of the governor. Next, an example of a simulation formula to be simulated will be described. In the following description, the water column is assumed to be an incompressible fluid, and is approximated based on the theory of stiffness. For the sake of simplicity, it is assumed that this water column has no friction loss.
[0031]
First, considering the waterway 101 and the upstream surge tank 106, the upper pond
The water column in the pipe line from 105 to the upstream surge tank 106 has a cross-sectional area A₁x length
L₁The force acting on the water column due to the surge tank water level rise acts in the direction of pushing back the water column, so the equation of motion is expressed by Equation (1).
[0032]
[Expression 1]
-Γ ・ ΔH_fu・ A₁= [(A₁・ L₁・ Γ) / g] × (dV₁/ Dt) (1)
Here, γ is the specific gravity of water, and when Equation 1 is transformed, Equation 2 is obtained.
[0033]
[Expression 2]
-ΔH_fu= (L₁/ G) x (dV₁/ Dt) (2)
On the other hand, since the difference between the inflow water amount and the outflow water amount to the surge tank changes the surge tank water level from the continuous equation, Equation 3 is established.
[0034]
[Equation 3]
(A₁・ V₁-A₂・ V₂) = A_fu・ (DΔH_fu/ Dt) (3)
Next, 102 hydraulic iron pipes will be examined. The water column in the hydraulic iron pipe has a cross-sectional area A₂x Length L₂And the water pressure fluctuation at the left end of the pipe is γ ・ △ H_fu・ A₂The water pressure fluctuation at the right end of the other pipe is γ ・ △ H_u・ A₂Therefore, Equation 4 holds. That is, Equation 5 is obtained.
[0035]
[Expression 4]
γ (ΔH_fu-ΔH_u) ・ A₂= [(A₂・ L₂・ Γ) / g] × (dV₂/ Dt) (4)
[0036]
[Equation 5]
ΔH_fu-ΔH_u= (L₂/ G) x (dV₂/ Dt) (5)
Therefore, Equation 8 is obtained.
[0037]
Next, the pump turbine 100 will be examined. Output P of water wheel_tCan be expressed by Equation 6.
[0038]
[Formula 6]
P_t= 9.8η · H · Q (6)
Here, η indicates the efficiency, and H indicates the effective head. The fluctuation of the effective head H is the upstream fluctuation △ H_uAnd downstream fluctuation △ H_LThe difference is expressed as in Expression 7.
[0039]
[Expression 7]
ΔH = ΔH_u-△ H_L ... (7)
Further, the flow rate Q is approximated by Formula 8.
[0040]
[Equation 8]
Q = K ・ Y ・ √H (8)
Here, Y indicates the guide vane opening. Furthermore, Equation 9 is obtained from the continuous equation.
[0041]
[Equation 9]
Q = A₂・ V₂= A_Three・ V_Three ... (9)
Next, the suction pipe 103 will be examined. The water column in the pipe of the suction pipe is cross-sectional area A_Threex Length L_ThreeAnd the water pressure fluctuation at the left end of the pipe is γ ・ △ H_L・ A_ThreeThe water pressure fluctuation at the right end of the other pipe is γ ・ △ H_fL・ A_ThreeTherefore, Equation 10 holds.
[0042]
[Expression 10]
γ (△ H_L-△ H_fL) ・ A_Three= [(A_Three・ L_Three・ Γ) / g] × (dV_Three/ Dt) (10)
That is, Formula 11 is obtained.
[0043]
## EQU11 ##
△ H_L-△ H_fL= (L_Three/ G) x (dV_Three/ Dt) (11)
Next, the discharge channel 104 and the downstream surge tank will be examined. First, the water column in the pipeline from the lower surge tank to the lower pond has a cross-sectional area A_Fourx Length L_FourSince the force acting on the water column acts in the direction of accelerating the water column due to the rise of the lower surge tank water level, Equation 12 is established.
[0044]
[Expression 12]
γ ・ △ H_fL・ A_Four= [(A_Four・ L_Four・ Γ) / g] × (dV_Four/ Dt) (12)
That is, Equation 13 is obtained.
[0045]
[Formula 13]
△ H_fL= (L_Four/ G) x (dV_Four/ Dt) (13)
On the other hand, since the difference between the inflow water amount and the outflow water amount to the lower surge tank from the continuous equation changes the lower surge tank water level, Equation 14 is obtained.
[0046]
[Expression 14]
(A_Three・ V_Three-A_Four・ V_Four) = A_fL・ (DΔH_fL/ Dt) (14)
Here, each coefficient is made dimensionless as shown in Equation 15 and linear approximation equations of Equation 2, Equation 3, Equation 5, Equation 6, Equation 7, Equation 8, Equation 9, Equation 11, Equation 13, and Equation 14 are obtained. If it calculates | requires, Formula 16 to Formula 25 will be obtained.
[0047]
[Expression 15]

[0048]
These expressions are dimensionless variables v₁, V₂, V_Three, V_Four, H_fu, H_fL, H_u, H_L, P_t, Q and y are linear approximation formulas, and the higher order terms of these variables are omitted as negligible small.
[0049]
[Expression 16]
v₁= -G · H₀・ H_fu/ (L₁・ V_Ten・ S)… (16)
[0050]
[Expression 17]
h_fu= (A₁・ V_Ten・ V₁-A₂・ V₂₀・ V₂) / (H₀・ A_fu・ S)… (17)
[0051]
[Formula 18]
v₂= G (H₀・ H_fu-H_u0・ H_u) / (L₂・ V₂₀・ S)… (18)
[0052]
[Equation 19]
p_t= H + q (19)
[0053]
[Expression 20]
h = (H_u0h_u-H_L0h_L) / (H_u0・ H_L0) = (H_u0h_u-H_L0h_L) / H₀
... (20)
[0054]
[Expression 21]
q = y + 0.5h (21)
[0055]
[Expression 22]
q = v₂= V_Three ... (22)
[0056]
[Expression 23]
v_Three= G (H_L0・ H_L-H₀・ H_fL) / (L_Three・ V₃₀・ S) ... (23)
[0057]
[Expression 24]
v_Four= G · H₀・ H_fL/ (L_Four・ V₄₀・ S) (24)
[0058]
[Expression 25]
h_fL= (A_Three・ V₃₀・ V_Three-A_Four・ V₄₀・ V_Four) / (H₀・ A_fL・ S) (25)
From this, the linearization model of the control object of the governor of the hydropower plant shown in FIG. 2 can be shown as in FIG. That is, a non-dimensional flow rate change q is generated by the non-dimensional opening degree y of the guide vane (water amount control means), and the water level h of the upstream surge tank made non-dimensional thereby._fu, Water level h of dimensionless downstream surge tank_fLCan be seen to respond. The upper surging block diagram and the lower surging block diagram shown in FIG. 3 are configured as shown in FIGS. 4 and 5, respectively. The response of the upstream surge tank water level and downstream surge tank water level to the flow rate change is a typical sine wave generation circuit. The upstream surge tank surging cycle and downstream surge tank surging cycle are respectively 2π√ (A_fu・ L₁/ A₁・ G), 2π√ (A_fL・ L_Four/ A_Four-G).
[0059]
FIG. 1 is a control block diagram of the governor of the present embodiment. 1 is a speed detector for detecting the rotational speed N of the pump turbine 100, X_nIs a speed detection signal detected by the speed detection unit 1, 2 is a speed adjustment unit for setting a reference value of the rotational speed, x₀Is a set value output from the speed adjustment unit 2, 3 is a set value x₀And speed detection signal X_nAnd a restoration signal X from a speed regulation rate setting unit to be described later_σAnd adder, X_εIs the signal calculated by the adder 3 and the input signal of the PID calculation circuit immediately downstream, 20 is a surging sensor for the upstream surge tank, 4a is a normally used proportional calculation element (P element), and 4b is operated by the surging sensor The proportional calculation element (P element) used when performing surging suppression is shown. The gain K of the former proportional calculation element_pa<Gain K of the latter proportional calculation element_pbIt has become. 5a indicates an integral calculation element (I element) that is normally used, and 5b indicates an integral calculation element (I element) that is used when the surging sensor operates, that is, when surging is suppressed. The former integral gain K_iaAnd the latter integral gain K_ibAnd K_ia<K_ibIt has become. 19a and 19b are contact points of the surging sensor 20 provided in front of the proportional calculation elements 4a and 4b and the integral calculation elements 5a and 5b, respectively, and swing when the surging sensor 20 is operated to open the proportional calculation element 4a. The arithmetic element 4b is closed, the integral arithmetic element 5a is opened, the integral arithmetic element 5b is closed, and both the proportional arithmetic element and the integral arithmetic element are switched.
[0060]
6 indicates a differential operation element (D element), and its output signal Z_d, Proportional element output signal Z_p, Output signal Z of the integral calculation element_iAre added by the adder 7. Output signal Z of this proportional calculation element_p, Output signal Z of the integral calculation element_i, Differential operation element output signal Z_dIs a guide vane opening command Z. The actual guide vane opening Y is fed back to the guide vane opening command Z, and the adding unit 8 takes a deviation. This deviation signal Y_{ε 1}Is input to the hydraulic servomotor 10 via the limiter 9. Θ of limiter 9_RIs the guide vane opening speed θ_R・ C_yAnd θ_LIs the closing speed θ_l・ C_yThe output signal Y of the limiter 9_{ε 2}Is the deviation signal Y_{ε 1}Is a signal that is restricted in consideration of the above opening / closing speed restriction. The hydraulic servo motor 10 is a kind of hydraulic amplifier, which constitutes a first-order lag element in the transfer function, amplifies the guide vane opening command z, and converts it into a guide vane opening Y with sufficient stroke and operating force. The guide vane that is the water amount control means is directly operated.
[0061]
The actual guide vane opening Y is fed back, and the addition unit 11 guides the guide vane opening setting signal Y from the output adjustment unit 13._aAnd the deviation is given. If the actual guide vane opening Y is the guide vane opening setting signal Y_aIs not reached, that is, Y <Y_aIn the case of, the open signal σ (Y_a-Y) will continue to be sent, so eventually Y = Y_aThen settle down at that stage. The open signal σ is set by the speed regulation rate setting unit 12, and the restoration signal X_σIs output. This open signal σ is the speed detection signal X_nIs a gain that determines the rate of change in the guide vane opening Y with respect to the change in the power, and is generally not changed once determined in consideration of the role of the plant in the power system.
[0062]
14 shows the entire block diagram shown in FIG. 3, and the actual guide vane opening Y is fed back. As described above, this block diagram 14 is a control block diagram of a pump turbine including a water channel system when simply expressed. The output P of the water turbine, which is the output of the block diagram 14_tAnd a total load LΣ, which will be described later, are taken, and this deviation is input to the rotation unit inertia effect calculation unit 16 to calculate the rotation speed N. The rotational speed N is fed back to the self-controllable computing unit 17a and the synchronizing operation computing unit 17b from the power system.
[0063]
In the calculation unit 17b, the rotational speed N is the rated speed (synchronous speed) N.₀Load power R indicating the synchronization effect that the power system brings back so as not to deviate from_LIs calculated. L is an external load applied to the generator directly connected to the water wheel shaft, and this external load L and load power R_LIs added to the generator load P_gIs calculated. The calculation unit 17a for the self-controllability of the pump turbine 100 calculates characteristics that combine mechanical loss and efficiency reduction that increase with the increase in rotational speed, and the turbine output loss R due to self-controllability due to the rotational speed change._TIs calculated.
[0064]
From the perspective of the water turbine, the power generation load P_gNot just loss R_TCan be regarded as a kind of load, and the output P of the water turbine_tLoad LΣ = P_g+ R_TCan be considered. Power generation load P_gAnd Ross R_TIs added to calculate the total load LΣ, and the turbine output P_tAnd the deviation (P_t-LΣ) is input to the rotation unit inertia effect calculation unit 16, and the rotation speed N is calculated as the output of the rotation unit inertia effect calculation unit 16.
[0065]
Incidentally, the governor shown in FIG. 1 has an external load L given to the generator and a guide vane opening setting signal Y given from the output adjusting unit 13 as signals given from the outside._aThere are two signals. The external load L depends on the fluctuation, and the rotational speed X_nCause speed fluctuations. On the other hand, a representative signal input to the output adjustment unit 13 is AFC (automatic frequency control), and in the case of AFC, a command issued exclusively from the viewpoint of frequency control of the power system. Special circumstances of the hydropower plant such as shaking are issued without being detected and are given by remote control from a remote central control station (not shown). Therefore, the rotational speed X_n, Guide vane opening setting signal Y_aSince either of the upstream and downstream surge tanks may be abnormally excited by any of the signals, the surging sensor can be monitored by the adder 3 that is the merging point of both signals so that the overall effect of both signals can be monitored. Arranged downstream.
[0066]
6 shows an input signal X to the PID calculation unit of the governor shown in FIG._εIt is a figure which shows an example of the surging sensor 20 which has input. 20A is an absolute value calculation unit, and 20B has an input of 0.004 (p_uIt is a switch that outputs 1 when it is above and 0 when it is below. 20C is a signal selection element that selects 0 when the output of the switch 20B is 1, and 0.2 when the output of the switch 20B is 0. 20D is an output of the switch 20B and the output of the signal selection element 20C. 20F is an integration element that integrates the output signal of the addition section 20D, 20E is provided in the previous stage of the integration element 20F, and the lower limit exceeds 0 so that the upper limit of the integration element 20F does not exceed 25 20G is a limiter that controls the passage / blocking of the signal sent to the integration element 20F so that the surging sensor is turned on when the output of the integration element 20F is 10 or more of the set value, and the surging sensor is turned off when the output is less than 10. It is a sensor operating part.
[0067]
Next, the operation of the surging sensor shown in FIG. 6 will be described with reference to the operation explanatory diagrams of the surging sensor shown in FIGS. The record 1 shown in FIG. 7 is an input signal X to the PID calculation unit of the governor._ε, Record 2 shows the output signal Z of the governor's PID calculation unit, record 3 shows the output signal of the integrating element 20F, and record 4 shows the output signal of the surging sensor actuating unit 20G. 8 shows the rotational speed N, and record 2 shows the guide vane opening setting signal Y._a, Record 3 indicates the guide vane opening degree Y. In this case, the guide vane opening setting signal Y given from the output adjusting unit 13 as in the record 2 shown in FIG._aIs a surging excitation signal.
[0068]
Time t_aThe input X of the PID calculation unit_εThe switch 20B outputs 1 when> 0.004. Then, the signal selection element 20C outputs 0. As a result, the output of the adding unit 20D becomes 1, the integration element 20F starts integration, and the output value of the integration element 20F indicated by the record 3 rises linearly. Time t_bThen, since the output of the integrating element 20F exceeds 10, the surging sensor is turned on at this stage. Time t_cThen, when the output of the integrating element 20F reaches 25, the rise immediately stops by the action of the limiter 20E. Time t_dThen, the input X of the PID calculation unit_ε<0.004, the switch 20B outputs 0, and the signal selection element 20C outputs 0.2, so that the output of the adder 20D becomes -0.2, and the output of the integration element 20F is 1/5 of the rise. Start descending on a gradient. Time t_eThen, the input X of the PID calculation unit again_ε> 0.004, and the output of the integrating element 20F starts to increase.
[0069]
The reason why the absolute value calculation unit 20A takes the absolute value is that the input X of the PID calculation unit_εIf the final change in water volume is the same even if is positive (when the water control means is opened) or negative (when the water control means is closed), the difference between starting from rising water level or starting from falling water is This is because surging with the same amplitude. Of course, as described above, the surging sensor can be simplified as much as possible even if the accuracy is somewhat deteriorated.
[0070]
| X at switch 20B_εThe reason for considering the amplitude of | is that the greater the amplitude, the greater the surging, regardless of whether it is positive or negative. Further, if the set value 0.2 of the signal selection element 20C is increased, the output of the integration element 20F is lowered more quickly, and the reset of the surging sensor is accelerated. Input X of the PID calculation unit that is repeated with a period much longer than the surging natural vibration period_εSince the risk of abnormal surging in the surging is considerably reduced in the case of vibration, the influence of the past vibration history can be almost ignored, but the setting value 0.2 of the signal selection element 20C makes this kind of judgment. It is. If the upper limit setting value 25 of the limiter 20E is lowered, the surging sensor can be easily reset even if the setting value of the signal selection element 20C is the same. Therefore, the setting of the signal selection element 20C and the limiter 20E is accurately considered as a set. The input X of the PID calculation unit_εSince the surging is attenuated even if the excitation period is much shorter than the period corresponding to the surging natural vibration with the same amplitude, the surging sensor may be turned off, but the surging sensor shown in FIG. it can. The accuracy of the surging sensor can be expected to be quite high if it is made by simulating the theory more closely with reference to FIG. 3, minimizing the operating range of the surging sensor, and sacrificing the frequency response performance of the governor. Can be minimized.
[0071]
As described above, time t in FIG._bIn FIG. 1, the surging sensor is turned on, and the contacts 19a and 19b of the surging sensor shown in FIG._pb), Integral element 5b (gain K_ib) Is selected, the operation of the guide vane (Y) is suddenly suppressed as in the record 3 shown in FIG. 6, and the surging is automatically suppressed to an allowable level. In the simulation analysis shown in FIGS. 7 and 8, it is assumed that the rotation speed N is constant from beginning to end as in the record 1 shown in FIG.
[0072]
The inventors conducted a simulation analysis with a nonlinear term added to a certain plant in order to confirm how effectively the above-described surging sensor operates in an actual machine. The results are summarized in FIG. In this case, the guide vane opening setting signal Y from the output adjustment unit 13_aA sine wave is given as a parameter, and verification is performed with a total of 12 cases of three kinds of amplitude and five kinds of periods as parameters. Here, regarding the determination of the necessity of the surging sensor, if no surging sensor is provided, the case where the allowable maximum water level of the target surge tank is determined as “necessary” and the case where it does not exceed is “unnecessary”. Guide vane opening setting signal Y_aThe surging sensor is actually turned on when the simulation analysis result is “necessary”, and is turned off when it is “unnecessary”, except for two cases of amplitudes of ± 0.49 and periods of 100 seconds and 400 seconds. . Two exception cases are errors due to simplification of the surging sensor, but the errors are on the safe side and can be judged to be sufficiently acceptable. The allowable maximum water level of the above-mentioned target surge tank is the value when this plant is connected to the power system, and is set to a value that will not cause the surge tank to overflow even if additional fluctuations added due to load interruption are taken into account. Yes.
[0073]
As described above, a low response setting to give the governor a low frequency response characteristic and a high response setting to give a higher frequency response characteristic are prepared, and the frequency band near the natural frequency of the surge tank is prepared. Since the low response setting is used in the operation at, the overall response gain of the governor itself up to the water amount control means is lowered, and the amplitude of the water amount control means can be lowered to a desired level. However, even if a vibration is applied at a frequency corresponding to the natural frequency of surging, with an amplitude that would otherwise prevent excessive surging, excessive surging will not occur.
[0074]
Further, since the surging sensor is provided, it is possible to accurately detect an operating condition in which excessive surging is a concern, so that the use range of the low response setting can be minimized. That is, it is possible to make the most of the normal setting that emphasizes the quick response while keeping the frequency response characteristic of the governor high.
[0075]
The gain of the integral element of the governor calculation unit is set to ensure the stability of the rotational speed N after the load is interrupted. The gain is set to a level that can suppress excessive surging. When the surging sensor operates, it is convenient to automatically select the lower gain as in the case of load interruption. In the case of an integral element, the output side does not fly no matter what time gain switching is performed, so that it is preferable as a switching target.
[0076]
If the gains of both the integral and proportional elements of the governor's computation section can be switched between high and low, and when the surging sensor is activated, the low gain side is automatically selected for both elements before and after switching. Since the degree of freedom is high as much as there is a proportional element, more suitable settings are possible in each state. However, in the case of a proportional element, if switching is performed during a transition, there is a possibility that the output side will fly, so switching is performed in consideration of this point.
[0077]
Although some logic can be considered as a surging sensor, it is not preferable to make it too complicated. Therefore, a predetermined index that can be easily calculated from the state quantity of the governor including the displacement of the flow rate control means downstream from the junction of the speed detection signal and the output adjustment signal and can be correlated with the magnitude of surging is simulated in advance. Find it by etc. Then, a method of predicting / detecting excessive surging by calculating the value of this index from the momentary governor state quantity can be considered. Note that since the total effect of the speed detection signal and the output adjustment signal becomes a problem in calculating the index, the governor state quantity downstream from the merging point of both signals is captured as data.
[0078]
As the governor state quantity for calculating the index for the surging sensor, it is preferable to select a state quantity that returns to zero or a value close thereto at the steady state. Considering when the governor is vibrated by a certain signal, surging (fluctuation in the water level of the surge tank) is related to the amount of change in any governor state quantity and not an absolute value.
[0079]
Even if the governor's state quantity itself does not return to zero or a value close to it at steady state, it is used to calculate an index after adding a predetermined operation such as differentiation and converting it to a state quantity that returns to zero or a value close to it at steady state. This is because the above points are taken into consideration. In addition, when applying a surging sensor, the calculation of the index includes not only the instantaneous value of the state quantity but also the history of the previous state quantity, so that the integration or storage operation is included. It is effective. Considering the displacement of the same water amount control means, for example, the displacement from 80% opening to 60% opening, the displacement from 100% opening to 80% opening is one cycle before the natural vibration of surging. If so, the surging due to the previous displacement overlaps with the surging due to the current displacement, and the fluctuation range of the surging is approximately doubled. In another example, when there is a displacement of the water amount control means from 100% opening to 80% opening before 1/2 period of the natural vibration of surging, the surging by the previous displacement and the current displacement Surging cancels out, and the fluctuation range of surging becomes almost zero.
[0080]
In another example, if the water flow control means has been displaced from 60% opening to 80% opening one cycle before the natural vibration of surging, the surging due to the previous displacement and the surging due to the current displacement cancel each other. Therefore, the fluctuation range of surging is very small. In another example, if the water flow control means has been displaced from 60% opening to 80% opening half a cycle before the natural vibration of surging, surging due to the previous displacement and surging due to the current displacement will occur. Overlapping, the surging fluctuation range is approximately doubled. As described above, since the amplification and attenuation of surging vary greatly depending on the displacement width, direction, and timing of the past water amount control means, as described above, a storage element such as an integral element that reflects past data is added to the index calculation logic of the surging sensor. The accuracy can be improved by inserting it. However, if too much accuracy is pursued, the index calculation logic becomes too difficult, so in practice, a certain degree of compromise is required. As an example of a compromise, an indicator calculation logic of a type that responds only to the absolute value and frequency of the fluctuation range, ignoring the direction of displacement given to the water amount control means, may be created. However, in this case, since it is dangerous that the accuracy is lowered in a direction where the surging sensor does not work, it should be designed so that it works even if it is not used. This consideration is applied to the index calculation logic that responds only to the absolute value and frequency of the fluctuation range in the above example. As a result, the surging sensor operates more than necessary, and each time the governor gain is lowered and the frequency response characteristic is lowered, but this degree is generally sufficiently acceptable.
[0081]
Note that the effect of integration or storage calculation used for calculating the index is attenuated with time if the surging excitation level of the input signal decreases. This is because surging due to the displacement of the past water amount control means attenuates with time.
[0082]
Arrangement of the band filter circuit is not limited to the output adjustment signal circuit, and it is similarly arranged if necessary as long as it is an application signal for finally controlling the flow rate control means. In the case of a configuration in which an opening degree upper limit device of a kind of water amount control means, generally called a load limit device, is repeatedly operated with a remote signal, the load limit device is also a target.
[0083]
FIG. 10 relates to surging suppression control during AFC (system automatic frequency control) operation in another embodiment of the present invention. 13A is a calculation unit of the output adjustment unit of the governor, 13B is an addition unit provided in the previous stage of the governor 13A, 13C is provided in the previous stage of the addition unit 13B, and is sent from the remote control station that controls the AFC of the entire power system to this plant. AFC command signal P to be commanded_afcIs input to the band filter, the output of the band filter 13C described later and the generator power P of the generator_gThe deviation is taken. Reference numeral 50 denotes a governor for inputting the rotational speed N, 100 denotes a pump turbine connected to the governor 50, and 200 denotes a generator connected to the pump turbine 100. P_xIs the output of the band filter 13C, P_gIndicates the actual generator power of the generator.
[0084]
Prior to the description of this embodiment, conventional AFC-compatible control performed on the plant side will be described. The governor 50 has a configuration in which the surging sensor 20, the proportional element 4b, the integrating element 5b, and the surging sensor contacts 19a and 19b are deleted from the configuration shown in FIG. AFC command signal P_afcIs directly input to the adder 13B, and the generator power P_gGenerator power P to follow_gIs negatively fed back to the adder 13B, and the calculator 13A receives the AFC command signal P_afcAnd generator power P_gThe calculation of integration is performed so that the deviation becomes smaller and finally zero, and the guide vane opening setting signal Y_aIs output. Guide vane opening setting signal Y_aThe guide vane opening Y is controlled following this, and the output p of the pump turbine 100 is_tIs controlled and mechanical output p_tIs the generator power P by the generator 200_gIs converted into and sent to the power system. The governor 50 has a guide vane opening setting signal Y._aIn addition, a rotation speed signal N is also input, but it is assumed that there is no fear of surging abnormal vibration with respect to the rotation speed signal N.
[0085]
Of course, from the AFC perspective, the AFC command signal P_afcTo generator power P_gIt is desirable that the frequency response characteristic on the plant side is high. On the other hand, if the frequency response characteristic is increased too much on the plant side, the guide vane opening setting signal Y_aThere is a problem that the surging becomes excessive due to excessive vibration. Therefore, in this embodiment, the operation of the band filter 13C will be described in particular. The transfer function of the band filter 13C shown in FIG. 10 is [(1 + T₂・ S) * (1 + T_Three・ S)] / [(1 + T₁・ S) * (1 + T_FourS)]. Where T₁To T_FourIs a predetermined time constant, and S is a Laplace operator. FIG. 11 shows the frequency response characteristics of the band filter as a Bode diagram. In FIG. 11, the horizontal axis represents frequency (HZ) and the vertical axis represents gain (db). Frequency 1 / (2πT₁) Is a time constant T so as to be lower than the surging resonance frequency.₁And the frequency 1 / (2πT_Four) Is a time constant T so as to be higher than the surging resonance frequency._FourSet. More preferably, the frequency 1 / (2πT₂) Is a time constant T so as to be lower than the surging resonance frequency.₂And the frequency 1 / (2πT_Three) Is a time constant T so as to be higher than the surging resonance frequency._ThreeSet. Thus, the time constant T₁, T₂, T_Three, T_FourIs set to AFC command signal P in the frequency band near the surging resonance frequency._afcBand filter P against_xThe frequency response gain of the output can be reduced to a factor of ten. Note that the surging abnormal vibration does not occur only at one surging resonance frequency, but it is necessary to assume a certain danger band above and below. For this, T₁, T₂, T_Three, T_FourNeeds to be separated from the surging resonance frequency with a predetermined margin. On the other hand, if this band filter 13C is attached, 1 / (2πT₁) Lower frequency and 1 / (2πT_FourIn a higher frequency band, a sufficiently high gain may be set without being caught by the surging abnormal excitation problem. That is, in this band, the AFC response performance can be increased arbitrarily. In the example shown in FIG. 8, a linear filter band filter is shown, but any linear or non-linear type may be used as long as the AFC response and the surging suppression can be compatible.
[0086]
As described above, in this embodiment, the frequency response characteristics of the governor are set lower for the input in the frequency band close to the surging natural frequency of the surge tank than in the input in the other frequency band. Since it has a band filter circuit, it does not require special judgment elements such as a surging sensor. Even if a signal that may cause excessive surging is given, the water volume control means that is the exit of the governor need only set the lower frequency response characteristic of the band filter so as not to be excessively shaken.
[0087]
If the band filter circuit is placed in front of the junction with the speed detection signal on the governor output adjustment signal application circuit, the band filter acts only on the output adjustment signal, and governor's original speed control operation It can be made not to interfere. In this case, it is assumed that a signal that may cause excessive surging can be limited to the output adjustment signal. An example of such an output adjustment signal is an AFC (automatic frequency control) signal given by remote control.
[0088]
As a specific example of a band filter, [(1 + T₂・ S) * (1 + T_Three・ S)] / [(1 + T₁・ S) * (1 + T_Four・ S)] (However, T₁To T_FourIs a predetermined time constant, and S is a Laplace operator). However, the present invention is not limited to this. A certain frequency band f_aTo frequency band f_bSo that the natural frequency of surging is in this frequency band f._aAnd frequency band f_bAnything can be used as long as it is in between.
[0089]
In the above description, the water amount control means corresponds to the guide vane in the power generation mode of the water turbine or the pump turbine, but considering the pumping operation mode of the variable speed pumping power generation machine, it corresponds to the rotation speed control means rather than the pump guide vane. This is because the amount of pumped water changes greatly if the rotational speed is changed, but does not change much even if the guide vane opening is changed. In the above description, the case where the two embodiments of the surging sensor and the band filter are used alone has been described, but both can be used together.
[0090]
In addition, a present Example can be characterized by comprising as follows. That is, the calculation unit of the governor includes a proportional element whose gain can be switched between high and low, and when the surging sensor operates, the integral element gain and the proportional element gain are automatically selected to a low gain. Hydropower machine of a hydropower plant with a surge tank.
[0091]
The hydraulic machine of the hydraulic plant provided with the surge tank according to claim 4, wherein the band filter circuit is arranged on the governor output adjustment signal application circuit and before the junction with the speed detection signal.
[0092]
The surging sensor continuously monitors a specific state quantity of the governor including the displacement of the flow rate control means downstream from the junction of the speed detection signal and the output adjustment signal, and correlates with the magnitude of the surging. The value of a predetermined index that has been confirmed in advance is calculated from the specific state quantity, and an excessive surging is detected based on the magnitude of the index. The hydropower plant having a surge tank according to claim 2. Hydraulic machine.
[0093]
The state quantity of the governor in which the specific state quantity returns to zero or a value close to it in a steady state, or even if it does not return to zero or a value close to it in a steady state, a predetermined calculation such as differentiation is applied to zero or close to it in a steady state A hydraulic power plant of a hydropower plant equipped with a surge tank that is used in place of a specific state quantity after being converted to a state quantity that returns to a value.
[0094]
The hydraulic machine of the hydraulic power plant provided with the surge tank in which the said calculating part includes the integral calculation or memory | storage calculation for reflecting the history of the state quantity before that in addition to the value of a state quantity for every calculation of the said index.
[0095]
A hydraulic power plant of a hydraulic power plant having a surge tank in which the integration or storage operation is attenuated with time when the surging excitation level of the input signal decreases.
[0096]
The hydraulic machine of the hydraulic plant provided with the surge tank according to claim 4, wherein the band filter circuit is arranged on a circuit of a specific application signal to a governor that finally controls the flow rate control means.
[0097]
The transfer function of the band filter is [(1 + T₂・ S) * (1 + T_Three・ S)] / [(1 + T₁・ S) * (1 + T_FourS)] or equivalent, and the natural frequency of the surge tank subject to surging suppression is 1 / (2π · T₁) And 1 / (2π · T_FourThe hydraulic machine for a hydraulic power plant having a surge tank according to claim 4, wherein T1 and T2 are adjusted so as to fall within the range of
[0098]
Next, an embodiment relating to a hydraulic machine suitable for adjusting the set value of the power of the generator or the motor at a high speed from a distance in relation to system control such as automatic frequency control (AFC) of the power system will be described.
[0099]
In the channel configuration configured as shown in FIG. 2, the behavior of the water turbine including the water hammer of the hydropower plant shown in FIG. 2, that is, the guide vane (water amount control means) opening degree Y which is the output of the governor is input. The linearization model of the controlled object of 100F shown in FIG.₂₀+ L_Three・ V₃₀) ・ It seems to be replaced with S. Here, each variable is made dimensionless and can be expressed by Equation 15.
[0100]
Opening change y of guide vane (water amount control means) → adder 100A → simulation term 100B of water hammer → (p_u) Coefficient 100D to convert unit water hammer to (m) unit → Adder 100E → Term 100F simulating acceleration of water column in pipeline → Total transfer function of circuit that makes a round of water turbine flow rate change q is the time constant (L₂・ V₂₀+ L_Three. V₃₀) / (2g · H₀) And is a first order lag element with a gain of 1.0. Guide vane (water volume control means) opening change y → adder 100A → simulation term 100B for water hammer → effective transfer change h has a time constant (L₂・ V₂₀+ L_Three・ V₃₀) / (2g · H₀) Becomes an incomplete differential element with a gain of 2.0. From this, the guide vane (water amount control means) opening degree change y to the turbine output change p_tThe total transfer function up to (1-T_w・ S) / (1 + 0.5T_w・ S) Where T_w= (L₂・ V₂₀+ L_Three. V₃₀) / (G · H₀).
[0101]
That is, when the guide vane is opened, the turbine output p_tWill eventually increase to a value corresponding to y, but will temporarily decrease, and conversely, when the guide vane is closed, the turbine output p_tIndicates that although it eventually decreases to a value corresponding to y, it temporarily increases conversely. This turbine output p_tThe effect of this temporary reverse response also appears in the change in the rotational speed N, which is also restored to the input side of the rotational speed governor. Therefore, when the hydropower plant is separated from the large power system and is substantially in a single power transmission state, or in the case of no-load operation after the load is completely cut off, the rotational speed control is performed even if there is this reverse response. The stability of the system must be ensured only by the rotational speed governor, and the proportional gain P and integral gain I of the rotational speed governor described later must be set sufficiently small. Further, increasing the differential gain D of the rotational speed governor to a certain extent contributes to stabilization of the rotational speed control system, but if it exceeds that, the stability is adversely affected.
[0102]
FIG. 12 is a control block diagram of the governor of the present embodiment. In FIG. 12, reference numeral 50 denotes a governor (also referred to as a power control unit or power control means) for inputting a rotation speed,
Reference numeral 100 denotes a pump turbine connected to the governor 50, and reference numeral 200 denotes a generator or electric motor connected to the pump turbine 100.
[0103]
A block diagram of the rotational speed governor 50 is as shown in FIG. 1 is a speed detector for detecting the rotational speed N of the pump turbine 100, X_nIs a speed detection signal detected by the speed detection unit 1, 2 is a speed adjustment unit for setting a reference value of the rotational speed, x₀Is a set value output from the speed adjustment unit 2, 3 is a set value x₀And speed detection signal X_nAnd a restoration signal X from a speed regulation rate setting unit to be described later_σAnd adder, X_εIs a signal calculated by the adder 3 and an input signal of a PID calculation circuit immediately downstream, 20 is a surging sensor for an upstream surge tank, 4 is a proportional calculation element (P element), 5 is an integral calculation element (I element), 6 indicates a differential operation element (D element), and its output signal Z_d, Proportional element output signal Z_p, Output signal Z of the integral calculation element_iAre added by the adder 7. Output signal Z of this proportional calculation element_p, Output signal Z of the integral calculation element_i, Differential operation element output signal Z_dIs a guide vane opening command Z. The actual guide vane opening Y is fed back to the guide vane opening command Z, and the adding unit 8 takes a deviation. This deviation signal Y_{ε 1}Is input to the hydraulic servomotor 10 via the limiter 9. Θ of limiter 9_RIs the guide vane opening speed θ_R・ C_yAnd θ_LIs the closing speed θ_l・ C_yThe output signal Y of the limiter 9_{ε 2}Is the deviation signal Y_{ε 1}Is a signal that is restricted in consideration of the above opening / closing speed restriction. The hydraulic servo motor 10 is a kind of hydraulic amplifier, which constitutes a first-order lag element in the transfer function, amplifies the guide vane opening command z, and converts it into a guide vane opening Y with sufficient stroke and operating force. The guide vane that is the water amount control means is directly operated.
[0104]
The actual guide vane opening Y is fed back, and the addition unit 11 guides the guide vane opening setting signal Y from the output adjustment unit 13._aAnd the deviation is given. If the actual guide vane opening Y is the guide vane opening setting signal Y_aIs not reached, that is, Y <Y_aIn the case of, the open signal σ (Y_a-Y) will continue to be sent, so eventually Y = Y_aThen settle down at that stage. The open signal σ is set by the speed regulation rate setting unit 12, and the restoration signal X_σIs output. This open signal σ is the speed detection signal X_nIs a gain that determines the rate of change in the guide vane opening Y with respect to the change in the power, and is generally not changed once determined in consideration of the role of the plant in the power system.
[0105]
Incidentally, the governor shown in FIG. 15 has an external load L given to the generator and a guide vane opening setting signal Y given from the output adjusting unit 13 as signals given from outside._aThere are two signals. The external load L depends on the fluctuation, and the rotational speed X_nCause speed fluctuations. On the other hand, a typical signal input to the output adjustment unit 13 is
AFC (automatic frequency control), and in the case of AFC, it is a command issued exclusively from the viewpoint of frequency control of the electric power system. Therefore, special circumstances of the hydropower plant such as surging abnormal vibration are issued without being detected. Provided remotely from a remote central control station not shown.
[0106]
The configuration of the AFC control system shown in FIG. 12 is as follows. Although the output adjustment unit 13 is controlled from a distance by AFC, an example in which an increase / decrease command for manual operation of power is also received is shown here. P_afcIndicates the power value required by AFC with the AFC command signal, P_gIndicates the actual generator power, and 13C is the deviation between them, ie, the power deviation P_{ε 1}The comparison part which calculates | requires is shown. Power deviation P_{ε 1}Is added with a raising / lowering command for manual operation in the adding unit 13B and added to the combined input signal P_{ε 1}And is input to the power deviation integrator 13A (also referred to as integral calculation means). Here, the power deviation integrator 13A is purely integrated, but also includes what can be approximately regarded as integral. For example, the power deviation P_{ε 1}The + / OFF / -1 pulse train is created according to the integral type, and the OFF time of the pulse train is set to the power deviation P._{ε 1}Some may be adjusted according to A proportional element 13D (also referred to as a parallel computing unit) is provided in parallel with the power deviation integrator 13A, and the output of the proportional element 13D is added to the output of the power deviation integrator 13A by the adder 13E. In this way, the power deviation P_{ε 1}Since the calculation of I is changed from I calculation to PI calculation, the responsiveness can be greatly improved. Output Y of adder 13E_aIs input to the rotational speed governor 50 described in detail in FIG. The pump turbine 100 has a turbine output P according to the input guide vane opening Y._tIs generated. Reference numeral 200 denotes a synchronous generator in operation connected to the power system, where the mechanical turbine output P_tIs the electrical output, ie the generator power P of the generator_gConverted.
[0107]
While the power deviation integrator 13A has a raising pulse signal for manual operation, the guide vane opening setting signal Y_aPer second K_{i θ} The guide vane opening setting signal Y is maintained while there is a lowering pulse signal._aPer second K_{i θ} Y at the speed of_aContinue to lower. If there is no pulse signal, guide vane opening setting signal Y_aStop raising and lowering. By the way, speed K_{i θ}Is too large, guide vane opening setting signal Y_aSince the car runs too fast and cannot be accurately stopped at the desired value, manual adjustment becomes difficult._{i θ} Is generally 1 (p_u) / 50sec ~ 1 (p_u) / 60 sec.
[0108]
Rotation speed N, guide vane opening setting signal Y_aAny change may cause both the upstream and downstream surge tanks of the turbine to be abnormally vibrated, but here, the explanation will focus on the upstream surge tank.
[0109]
16 and 17 show the output of the output adjusting unit 13 in FIG. 15, that is, the guide vane opening setting signal Y._aIt is a Bode diagram which shows the example of a response of the upstream surge tank when changing to a sine wave form. FIG. 16 shows the proportional gain K of the rotational speed governor._p, Integral gain K_iFIG. 17 shows the proportional gain K of the rotation speed governor._p, Integral gain K_iShows a case where is set relatively small. In this case, the natural frequency of the upstream surge tank is 0.0000474 Hz, and in all cases, the upstream surge tank water level h is around 0.00474 Hz._fuThe response gain of is rising rapidly. The peak value of the response gain at the natural frequency of the upstream surge tank is 24.4 (db) in FIG. 16, which is higher than 7.6 (db) in FIG. 17, and this difference 16.8 (db ) Is equivalent to 6.9 times. Even if the setting shown in FIG. 16 is used, there is no problem if the upper surge tank does not overflow. However, if there is a possibility of overflow, a countermeasure is required to lower the peak value. That is, the input guide vane opening setting signal Y_aLimit amplitude or proportional gain K_p, Integral gain K_iMeasures to lower it are necessary.
[0110]
In the following description, it is assumed that the allowable maximum value of the peak value of the response gain at the natural frequency of the upstream surge tank is equivalent to 7.6 (db) shown in FIG. FIG. 18 shows the frequency response characteristics of AFC when the proportional element 13D is not provided, that is, the AFC command P_afcTurbine output for_tThe response performance is shown. The turbine output P_tAnd generator power P_gSince there is almost no delay between_afcGenerator power P against_gThe response performance may be good. In this case, the proportional gain K of the rotation speed governor_p, Integral gain K_iAre set the same as those shown in FIG. Thus, when the proportional element 13D is not provided, the AFC response gain is greatly reduced to 1/100 or less at about 0.01 Hz or more, and an AFC response cannot be expected at about 0.01 Hz or more.
[0111]
FIG. 20 shows the frequency response characteristics of power during AFC operation of this embodiment. Proportional element 13D is provided as a parallel circuit, and gain K_{p θ}Since 1.0 is set to 1.0, it can be seen that the characteristics in the frequency band of 0.01 Hz or higher are greatly improved with respect to the frequency response characteristics shown in FIG.
[0112]
FIG. 19 is a Bode diagram of the upstream surge tank water level response during AFC operation of the present embodiment. The conditions are the same as those shown in FIG. As can be seen from FIG. 19, the surging of the upstream surge tank is also expanded with the improvement of the AFC response.
[0113]
As explained above, parallel computing means that inputs the same power deviation signal as the power deviation integral computing unit is provided in parallel with the power deviation integrating computing unit of the one-round control system for the power command, and power is supplied only when there is a transient with power deviation. Since a signal that enhances the response of the deviation integration calculator is output, the response delay is transiently maintained while maintaining the relationship (power command from a distance = actual power). It can be compensated accurately. In particular, when the sum signal obtained by adding the output of the power deviation integration calculator and the output of the parallel calculation means is applied as a kind of bias signal to the rotation speed governor calculation section of the rotation speed control system, the parallel calculation means rotates. Since it is outside the speed control loop, it is possible to freely improve the power response to a power command from a distance without affecting the circular transfer function of the rotational speed control system. Even if the power deviation integration calculator has a sufficiently low gain so that it can receive an increase / decrease command for manual operation of power, the power deviation integration calculator is bypassed and the power for the power command from a distance is bypassed. The response gain can be increased freely.
[0114]
In addition, by providing a proportional calculation as a parallel calculation means, it is possible to replace a simple I calculation using only a power deviation integrator with a P + I (proportional + integral) calculation, and in terms of frequency response, gain reduction and phase delay compensation are free. Thus, the response of the power control system to a power command from a distance can be more appropriately optimized. Further, by providing a proportional calculation + differential calculation in the parallel calculation means, a simple I calculation using only a power deviation integrator can be replaced with a P + I + D (proportional + integration + differentiation) calculation, and power control for a power command from a distance can be achieved. The frequency response characteristic can be improved more accurately and can be optimized. Regardless of special circumstances on the side of the rotational speed control system downstream of the rotational speed governor calculation unit, for example, the situation where the PID gain of the rotational speed governor cannot be increased freely, it is possible to optimize more accurately.
[0115]
FIG. 13 shows an AFC control system according to another embodiment of the present invention. This embodiment is configured in the same manner as the embodiment shown in FIG. 12, but in this embodiment, a band filter 13F is provided in the receiving section of the AFC input. FIG. 14 shows frequency response characteristics of the band filter section shown in FIG. That is, it is a Bode diagram showing frequency response characteristics of the band filter 13F alone. In this band filter, the response gain is 1 / (2πT₁) (Hz) starts to drop, 1 / (2πT₂) (Hz) ~ 1 / (2πT_Three) (Hz) is the lowest, 1 / (2πT_Three) (Hz), and starts to rise again, 1 / (2πT_Four) (Hz) to return to the original level. The natural frequency 0.00474 (Hz) of the upstream surge tank is 1 / (2πT₂) (Hz) ~ 1 / (2πT_Three) (Hz) Time constant T₂, T_ThreeIs set. In addition, even if the natural frequency of the upstream surge tank does not accurately enter the low gain portion of the band filter, 1 / (2πT₁) (Hz) to 1 / (2πT_Four) (Hz), it is not efficient, but an effect can be expected.
[0116]
FIG. 22 is a Bode diagram of the power response during the AFC operation of this embodiment. The condition is 0.00474 Hz is 1 / (2πT₂) (Hz) ~ 1 / (2πT_Three) A band filter set to be in the frequency band of (Hz) and K_{i θ}The setting is the same as that shown in FIG. 20 except that is reduced to 1/10. As a result, the power response around 0.00474 Hz was slightly reduced, but there was no effect at 0.1 Hz or higher.
[0117]
FIG. 19 is a Bode diagram of the upper surge tank water level response during the AFC operation of this embodiment, and the conditions are the same as those in FIG. The peak value at the natural frequency 0.00474 Hz of the upstream surge tank is 0.89 (db), which is significantly lower than 24.2 (db) shown in FIG. Moreover, it is significantly lower than the above-described overflow determination level of 7.6 (db). In the above example, the linear model [(1 + T₂・ S) * (1 + T_Three・ S)] / [(1 + T₁・ S) * (1 + T_FourAlthough S)] has been described as an example, anything may be used as long as the effect of lowering the frequency response gain of surging is finally obtained in the vicinity of the surging resonance frequency.
[0118]
Although only the fluctuation of the water level in the upstream and downstream surge tanks has been described as the resonance potential, if there are similar resonance potentials for the rotational speed governor itself and its controlled object, the same countermeasures should be taken for each of them. Good.
[0119]
As described above, according to the present embodiment, a band filter is provided in the remote command receiving unit. Therefore, as a result of the power control response measures described above, abnormal addition in a specific frequency band such as surging resonance of a surge tank is performed. Even if there is a possibility of oscillation, the power control response of that specific frequency band can be accurately lowered to avoid the problem, and the power control response can be fully increased in other non-hazardous frequency bands Become.
[0120]
When P + I + D calculation is used for remote power control and a band filter is used for the remote command receiver, P + I calculation is used for remote power control and a band filter is used for the remote command receiver. Fine adjustment is possible.
[0121]
Note that the transfer function of the band filter is [(1 + T₂・ S) * (1 + T_Three・ S)] / [(1 + T₁・ S) * (1 + T_Four・ S)] (However, T₁To T_FourIs a predetermined time constant, S is a Laplace operator, and T₁<T₂<T_Three<T_Four), The frequency response characteristic is 1 / (2π · T₁) To 1 / (2π · T_Four) So that the specific frequency band in which the resonance on the controlled object side such as the surging resonance frequency is expected falls within this range.₁, T_FourResonance can be accurately prevented by adjusting.
[0122]
The frequency response characteristic of this filter is 1 / (2π · T₂) And 1 / (2π · T_Three) So that a specific frequency band in which resonance is expected falls within this range.₂, T_ThreeIt is more preferable to adjust.
[0123]
The band filter is not limited to the above example, but a certain frequency band f_aTo f_bThe frequency response characteristic is lower than usual, and the specific frequency band in which resonance is expected is the frequency f._aAnd frequency f_bAnything that can be put in between.
[0124]
The present embodiment can be characterized as having the following configuration. That is, a water wheel having a runner, a generator or an electric motor that is mechanically directly connected to the runner and electrically connected to an electric power system, an electric power control unit that controls an output of the electric generator or an input of the electric motor, and electric power Manual operation command means for manually giving up / down operation commands, remote command means for giving a required value of power from a distance, power restoring means for restoring an actual power value, and requested values from the remote command means And a deviation deriving unit for obtaining a deviation of the actual power value from the power restoring unit, a power deviation signal output from the deviation deriving unit, and a speed suitable for visual confirmation according to a command from the manual operation command unit And an integral type power command calculation means for performing an integration or equivalent calculation for inputting a power increase / decrease command signal to the power control means, and in the case of power control from a distance, the deviation derivation is performed. Stage → integral type power command calculating means → water wheel and generator / motor → power restoring means negative feedback circuit is configured, and the power deviation signal is input and the integral type power command calculating means The parallel computing means is arranged in parallel with the output to correct the output of the integral power command computing means, and the parallel computing means returns the response of the integral power command computing means when there is a transient power deviation. A hydraulic machine characterized by outputting a signal to increase and returning the output to zero or substantially zero when returning to a steady state.
[0125]
The hydraulic machine according to any one of claims 5 to 8, wherein the parallel computing unit has a proportional computing element and a differential computing element connected in series.
[0126]
The hydraulic machine according to any one of claims 5 to 8, wherein the arithmetic unit travels at a speed suitable for visual confirmation and inputs an electric power increase / decrease command signal provided manually.
[0127]
9. The output signal acting on the power control unit to reduce the power deviation is continuously increased while the arithmetic unit has a power deviation signal output from the comparison unit. A hydraulic machine according to any one of the above.
[0128]
A band filter is provided in front of the comparison unit or deviation deriving means and inputs a required value of power from a distant place, and the response gain of the band filter corresponds to a fluctuation input in a specific frequency band. The hydraulic machine according to any one of claims 5 to 8, wherein the hydraulic machine is lower than a fluctuation input in another frequency band.
[0129]
The hydraulic machine according to claim 5 or 8, wherein when the characteristic of the computing unit is a transient with a power deviation, a signal that enhances the response is output, and when returning to a steady state, the output is returned to zero or substantially zero. .
[0130]
T₁, T₂, T_Three, T_FourT with a predetermined time constant₁<T₂<T_Three<T_Four, S is the Laplace operator, and the transfer function of the band filter is [(1 + T₂・ S) * (1 + T_Three・ S)] / [(1 + T₁・ S) * (1 + T_FourS)] or equivalent, and the specific frequency band that may cause resonance is 1 / (2π · T₁) And 1 / (2π · T_Four) T₁, T_FourSet hydraulic machine.
[0131]
【The invention's effect】
According to the present invention, it is possible to guarantee that abnormal vibration of surging can be automatically prevented. Therefore, without sacrificing safety, the capacity of the surge tank installed in the upstream / downstream waterway (specifically, the cross-sectional area and height) ) Can be significantly reduced and civil engineering costs can be reduced. Moreover, the surging sensor method or the band filter method can be achieved without drastically changing the governor, and the cost increase for this is negligible in terms of effect. By using a band filter, governor response characteristics such as AFC can be greatly improved in a manner consistent with surging.
[0132]
In addition, even when both the rotational speed control system and the power control system that responds to the remote command ultimately control the same operating end, the response of the power control system that responds to the remote command is the response of the rotational speed control system. It can be rationally optimized without impairing performance, particularly stability, and particularly the response gain can be greatly improved.
[0133]
In addition, even when the power deviation integral gain is not sufficiently high, as in the case where the power deviation integral calculator also receives an increase / decrease command for manual operation of power, the responsiveness of the power control system to the remote command can be increased freely. be able to.
[0134]
In addition, abnormal vibration phenomena in specific frequency bands such as surge tank surging of upstream and downstream water channels can be reasonably prevented, and the response of the one-round control system can be maintained to the maximum in other frequency bands. it can.
[Brief description of the drawings]
FIG. 1 is a block diagram of a governor according to an embodiment of the present invention.
FIG. 2 is a water channel configuration diagram of a hydropower plant having surge tanks in both upper and lower water channels.
FIG. 3 is a block diagram illustrating a linearization model of a governor to be controlled.
FIG. 4 is a block diagram of the upper surging tank shown in FIG.
FIG. 5 is a block diagram of the lower surging tank shown in FIG. 3;
FIG. 6 is a configuration diagram illustrating an example of a surging sensor.
FIG. 7 is a diagram illustrating the operation of a surging sensor.
FIG. 8 is a diagram illustrating the operation of a surging sensor.
FIG. 9 is a diagram illustrating an analysis example of evaluation of detection accuracy of a surging sensor.
FIG. 10 is a block diagram illustrating an example of a band filter.
11 is a Bode diagram showing frequency response characteristics of the band filter shown in FIG. 10;
FIG. 12 is a diagram showing a configuration of an AFC control system according to another embodiment of the present invention.
FIG. 13 is a diagram showing a configuration of an AFC control system according to another embodiment of the present invention.
14 is a diagram illustrating frequency response characteristics of the band filter unit of FIG. 13;
FIG. 15 is a block diagram of a rotation speed governor.
FIG. 16 shows Y in FIG._aIt is a Bode diagram which shows the response of the surge tank when changing to a sine wave shape.
FIG. 17 shows Y in FIG._aIt is a Bode diagram which shows the response of the surge tank when changing to a sine wave shape.
18 is a diagram showing frequency response characteristics of AFC when the parallel circuit of FIG. 15 is not provided.
FIG. 19 is a Bode diagram of an upper surge tank water level response during AFC operation of the embodiment of FIG. 12;
20 is a diagram showing frequency response characteristics of electric power during AFC operation of the embodiment of FIG.
FIG. 21 is a Bode diagram of an upper surge tank water level response during AFC operation of the embodiment of FIG. 13;
22 is a Bode diagram of power response during AFC operation of the embodiment of FIG. 13;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Speed detection part, 2 ... Speed adjustment part, 3 ... Adder, 4, 4a, 4b ... Proportional calculation element, 5, 5a, 5b ... Integration calculation element, 6 ... Differentiation calculation element, 7, 8, 11 ... Addition , 9 ... Limiter, 10 ... Hydraulic servo motor, 12 ... Speed regulation rate setting unit, 13 ... Output adjustment unit, 14 ... Block diagram, 16 ... Calculation unit, 17a, 17b ... Calculation unit,
DESCRIPTION OF SYMBOLS 20 ... Surging sensor, 100 ... Pump turbine, 101 ... Water conduit, 102 ... Hydraulic iron pipe, 103 ... Suction pipe, 104 ... Discharge channel, 105 ... Upper pond, 106 ... Upstream surge tank, 107 ... Downstream surge tank, 108 ... Shimoike.

Claims (5)

A hydraulic machine upstream or downstream pipe is installed in a hydroelectric plant with a surge tank, and a governor for controlling the flow control means and movable flow control means, the same as the input signal to the governor A surging sensor using a signal as an input signal, wherein the input signal is determined to be excessive surging or a precursor thereof for an input signal in a frequency band near the natural frequency of the surge tank, and the input signal is other A surging sensor that determines that no excessive surging or a precursor thereof has occurred for an input signal in the frequency domain of the frequency domain, and the governor, when the surging sensor determines that an excessive surging or a precursor thereof, The frequency response characteristic of the governor is set to a low response setting, and the surging sensor is over surging or its precursor If it is determined not to have occurred, the hydraulic machine before hydroelectric plant frequency response characteristics of the governor with a surge tank, characterized in that the high-response setting and that is a high frequency response characteristic than the low response setting. 2. The governor according to claim 1, wherein the governor is configured so that the integral element gain can be switched between high and low, and the low gain side is automatically selected when the surging sensor determines that it is excessive surging or a precursor thereof. Hydropower machine of a hydropower plant with a surge tank. A hydraulic machine installed in a hydropower plant with a surge tank in the upstream or downstream pipeline, which includes a guide vane, a governor for controlling the opening degree of the guide vane, and an automatic frequency control signal as input. An output adjustment unit that outputs a setting signal to the governor, and a band filter circuit provided in a preceding stage of the output adjustment unit, the frequency response characteristic of the band filter circuit being a frequency close to the surging natural frequency of the surge tank A hydraulic machine for a hydraulic power plant having a surge tank, characterized in that the frequency response characteristic of the governor is set to be lower with respect to the input of the band than the input of the other frequency band. 4. The output adjustment unit according to claim 3, wherein the output adjustment unit receives a power deviation between a required value of power from a distance and an actual power value, and inputs the power deviation obtained by the comparison unit, and guide vanes to the governor . A surge tank comprising an arithmetic unit that outputs an opening setting signal, the arithmetic unit comprising a power deviation integrator and a parallel arithmetic unit having a proportional element provided in parallel to the power deviation integrator Hydraulic power plant of hydraulic power plant . 4. The output adjustment unit according to claim 3, wherein the output adjustment unit inputs a power deviation between a required value of power from a distance and an actual power value, and receives the power deviation obtained by the comparison unit, and guide vanes to the governor . An arithmetic unit that outputs an opening setting signal is provided, and the arithmetic unit is arranged in parallel with an integral arithmetic unit or an equivalent arithmetic unit, and has a parallel arithmetic unit that corrects the output of the integral arithmetic unit or the equivalent arithmetic unit It is characterized by having a characteristic of outputting a signal that enhances the response of an integral computing unit or an equivalent computing unit when there is a power deviation and returning the output to zero or substantially zero when returning to a steady state. Hydraulic plant hydraulic machine with surge tank .

Images