PROBLEM TO BE SOLVED: To improve the control responsiveness by selecting the control by a main steam pressure controller in the case when a measured value of the main steam pressure is lower than a predetermined value, and controlling the opening with a constant rate of change to achieve the optimum opening as a target value in the case when a measured value of the opening of a speed governing valve is larger than the optimum opening. SOLUTION: A generator 16 is operated, a speed governing valve 5 is fully opened and the steady operation is performed by a controller 6 when the steam is supplied from a steam supply tube 15 to a steam turbine 4, and then a breaker 17 is closed to energize an electric power system 18. On this occasion, the pressure of the steam is measured by a pressure sensor 9, a measured value is compared with a predetermined value by a main steam pressure controller 7, and the control by the main steam pressure controller 7 is selected by a low selector 8 when the measured value is lower than the predetermined value. Further the opening of a speed governing valve 5 is measured by an opening sensor 14, a measured value is compared with the optimum opening by a speed governing valve controller 12, and the opening of the speed governing valve 5 is changed (reduced) by a constant rate of change to achieve the optimum opening as a target value.
【課題】 調速弁の開度制御を他の制御装置から、主蒸 気圧力の計測値と設定値との比較結果に基づく主蒸気圧 制御装置による制御への切り替え時における整定時間を 短縮することにより蒸気タービン制御の応答性を向上す るとともに、制御要素の調整が簡略化された蒸気タービ ンの蒸気圧力制御方法及び制御装置を提供する。
【解決手段】 蒸気タービンへの蒸気供給管を開閉する 調速弁の開度を制御するにあたり、前記調速弁の開度が 主蒸気圧力を維持しうる最適開度（Ｋ0 ）以下となるま で、調速弁開度を変化率一定となるよう制御し、その後 は調速弁開度の急激な変動無しにＰＩＤ制御による主蒸 気圧制御に移行する。