| 摘要 |
PURPOSE:To correctly open a main steam control valve from a fully closed position to an opening start position and prevent a turbine from its overspeed due to an excessive opening of the valve, by detecting an opening of the control value at rubbing check control of the steam turbine. CONSTITUTION:A valve opening signal from an opening detector 3 of a main steam control valve 2 is input to a control circuit 7 of a steam turbine together with a rotary speed signal from speed detectors 4, 5, and a control signal is fed to a motor 6 from the circuit 7 to control an opening of the valve 2 at rubbing check control. When this valve 2 is opened from a fully closed position to an opening start position where steam flows in the turbine, an opening of the valve is detected, and the valve 2 can be correctly stopped at its opening start position, then the turbine can be prevented from rapidly increasing its speed due to an excessive opening. |
