Control valve control method and control device, and power generating plant utilizing same

Patent metadata

Field	Value
Publication number	US-10557379-B2
Application number	US-201715597279-A
Country	US
Kind code	B2
Filing date	May 17, 2017
Priority date	Jul 17, 2013
Publication date	Feb 11, 2020
Grant date	Feb 11, 2020

Abstract

A gas turbine plant including a gas turbine and a compressor is provided with a steam turbine plant including a steam turbine and a condenser, and, an exhaust heat recovery boiler. Steam from the exhaust heat recovery boiler is directly flown to the condenser of the steam turbine plant through a bypass control valve. A pressure sensor detects pressure in a turbine bypass system. A controller outputs, based on a set value from an input device and a process value from the pressure sensor, an open level instruction value to the control value so as to make the process value consistent with the set value in a predetermined sampling cycle. A corrector corrects the set value from the input device in a direction in which the open level instruction value decreases when the open level instruction value from the controller becomes a value that substantially fully opens the control valve.

First claim

What is claimed is:

1. A method for controlling a control valve, comprising:
outputting from a controller, based on a set value and a process value, an open level instruction value to a control valve so as to make the process value approach the set value in accordance with a predetermined sampling cycle;
decreasing the open level instruction value to the control valve when the set value increases to a certain value; and
correcting the set value to decrease the open level instruction value when the open level instruction value from the controller exceeds a predetermined value.

2. The method for controlling a control valve according to claim 1 , wherein the set value is corrected so as to increase based on a highest open level instruction value during a time period from a past to a current time.

3. The method for controlling a control valve according to claim 2 , wherein when the open level instruction value from the controller becomes equal to or smaller than a certain threshold value, the increased set value is returned to an initial set value.

4. The method for controlling a control valve according to claim 1 , wherein when the open level instruction value from the controller becomes equal to or smaller than a certain threshold value, the increased set value is returned to an initial set value.

5. A control device for a control valve comprising:
a first input device for a set value;
a second input device for a process value;
a controller outputting, based on the set value and the process value received from the respective input devices, an open level instruction value to a control valve so as to make the process value approach the set value in accordance with a predetermined sampling cycle, the controller decreasing the open level instruction value to the control valve when the set value increases to a certain value; and
a corrector correcting the set value from the input device to decrease the open level instruction value when the open level instruction value from the controller exceeds a predetermined value.

Assignees

• Toshiba Kk

Inventors

• Watanabe Hironori
• Tobo Masayuki
• Yamasaki Takuji
• Juangsa Firman Bagja

Classifications

• F01K23/10 Primary

  with exhaust fluid of one cycle heating the fluid in another cycle (F01K17/025 takes precedence) · CPC title

• Y02E20/16

  Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT] · CPC title

• F01K9/04

  with dump valves to by-pass stages · CPC title

• F01D21/00

  Shutting-down of machines or engines, e.g. in emergency; Regulating, controlling, or safety means not otherwise provided for · CPC title

• F16K31/02

  electric {(F16K31/004 takes precedence)}; magnetic · CPC title