System and method for scheduling startup of a combined cycle power generation system

• US 8,195,339 B2
• Filed: 09/24/2009
• Issued: 06/05/2012
• Est. Priority Date: 09/24/2009
• Status: Active Grant

• Current Assignee: GE Infrastructure Technology, LLC (General Electric Company)
• Original Assignee: General Electric Company
• Inventors: Long, Christopher Eugene, Holzhauer, Daniel, D'Amato, Fernando, Peterson, Susan, Blasini, Luis, Punjala, Ratna Manedhar, Saraswat, Rohan
• Primary Examiner(s): Decady, Albert
• Assistant Examiner(s): GARLAND, STEVEN R
• Application Number:
  US12/565,945
• Publication Number:
  US 20110071692A1
• Time in Patent Office: 985 Days
• Field of Search: 700/291, 700/287, 606/46, 415/13
• US Class Current: 700/291
• CPC Class Codes: G05B 17/02 electric
• CPC Class Codes: Y02E 20/16 Combined cycle power plant [CCPP], or combined cycle gas turbine [CCGT]

Abstract

A method for forecasting a start period for a combined cycle power generation system including a gas turbine engine, a steam turbine and a computer control system, the method including: inputting a desired time at which the power generation system is to reach a dispatchable load; inputting a current value of a predetermined operational condition of the power generation system; the computer control system retrieving historical data relating the predetermined operational condition to prior start periods of the power generation system or a similar power generation system; the computer control system executing an algorithm which generates a forecasted start time based on the desired time, current value and the retrieve data, wherein the power generation system is predicted to reach the dispatchable load at the desired time when started at the forecasted start time, and the computer system outputting the forecasted start time to the output device.

Claims

1. A method for forecasting a start period for a combined cycle power generation system including a gas turbine engine, a steam turbine and a control system including having a user input and a display, the method comprising:

a. determining a current turbine temperature of the steam turbine at a current time;

b. determining a target time period to dispatchable load as a period from the current time to a target time at which the power generation system is to be at a predefined power output level;

c. selecting a forecasted start time period as a period from the current time to a start time for a startup sequences of the power generation system;

d. based on the forecasted start time period and the current turbine temperature, determining an estimated turbine starting temperature at the forecasted start time;

e. using the estimated turbine starting temperature, determining an estimated time period for the startup sequence;

f. summing the forecasted start time period and the estimated time period for the startup sequence to calculate a total time period;

g. comparing the total time period to a target time period from a first time to the target time;

h. using the forecasted start time period to determine when to start the startup sequence, if the comparison in step (g) determines the total time period to be within a predetermined period of the target time period, and

i. decrementing the forecasted start time, if the comparison in step (g) indicates that the total time period is outside of the predetermined period of the target time period, and thereafter repeating steps (d) to (h).

2. The method of claim 1 wherein in step i steps d to h are repeated until the comparison determines the total time period is within the predetermined period of the target time period.

3. The method of claim 1 wherein in step i the forecasted start time period is decremented by an amount of time equal to the predetermined period in step h.

4. The method of claim 1 wherein the step d includes using an electronic model of a steam turbine which receives as inputs the current turbine temperature and a period between the current time and the forecasted start time, and outputs the estimated turbine starting temperature.

5. The method of claim 4 wherein the electronic model is a look-up table having data fields for turbine temperature correlated to times in a cool-down period of the turbine.

6. The method of claim 1 wherein the step e includes accessing a historical database of startup sequences for a generation system, and the database has data fields for turbine temperature correlated to times during a startup process.

7. The method of claim 1 wherein turbine temperature is a metal temperature of a rotor in the steam turbine.

8. The method of claim 1 wherein the predefined power output level is a dispatchable load power output level.

9. The method of claim 1 where the current time is a time at which a rotor metal temperature measurement was recently recorded.

10. A method for forecasting a start time for a combined cycle power generation system including a gas turbine engine (GT), at least one steam turbine (ST) and a controller having a user input and a display, the method comprising:

a. entering into a control system a temperature of at least one of the steam turbines, wherein the temperature corresponds to a recent time;

b. determining by the control system a target time period as a period from the recent time to a target time at which the power generation system is scheduled to be at a dispatchable load;

c. selecting by the control system a forecasted start time period as a period from the recent time to a start of a startup sequence for the power generation system;

d. based on the forecasted start time period and a first temperature, determining by the controller an estimated turbine temperature to occur at a forecasted start time;

e. based on the estimated turbine temperature, determining by the controller an estimated time period for the startup sequence;

f. summing by the controller the forecasted start time period and the estimated time period for the startup sequence and generating an estimated total time period from the recent time to the end of the startup sequence;

g. comparing by the controller the estimated total time period and the target time period;

h. the controller outputting the forecasted start time, if the controller in making the comparison determines the estimated total time period is within a predetermined period of the target time period, and

i. decrementing by the controller the forecasted start time, if the controller determines that the estimated total time period is outside of the predetermined period of the target time period, and repeating steps d to h.

11. The method of claim 10 wherein in step i steps d to h are repeated until the comparison determines the estimated total time period is within the predetermined period of the target time period.

12. The method of claim 10 wherein in step i the forecasted start time period is decremented by an amount equal to the predetermined period.

13. The method of claim 10 wherein the step d includes using an electronic model of a steam turbine which receives as inputs the first temperature and a period between the first time and the forecasted start time, and outputs an estimated rotor temperature corresponding to the forecasted start time.

14. The method of claim 10 wherein the step e includes accessing a historical database of startup sequences having data fields for steam turbine rotor temperature correlated to times during a startup sequence.

15. The method of claim 10 wherein at least one steam turbine is a reheat steam turbine.

16. A control system for a combined cycle power generation system comprising a gas turbine and a steam turbine, the control system including a processor and an electronic memory storing a database of prior startup processes and a computer program for scheduling a start time for a future startup process, the program causing the processor to perform process steps comprising:

a. entering as an input to the control system a current temperature of the steam turbine;

b. determining by the control system a time period to dispatchable load period as a period from a current time to a target time at which the power generation system is scheduled to be at a dispatchable load;

c. selecting a forecasted start time period as a period from a current time to a start of a startup process for the power generation system;

d. based on the forecasted start time period and the current temperature of steam turbine, determining an estimated rotor temperature at a forecasted start time;

e. based on the estimated rotor temperature, determining an estimated time period for a startup process which is a period initiated at the forecasted start time and ending when the power generation system reaches a predefined dispatchable load;

f. summing the forecasted start time period and the estimated time period for the startup process to generate a total time to dispatchable load;

g. comparing the total time to the dispatchable load to a time period from the current time to the target time;

h. based on the forecasted start time period, determining when to start the startup process, if the processor in making the comparison determines the total time to dispatchable load to be within a predetermined period of the current time to the target time, and

i. decrementing the forecasted start time by a predetermined period, if the processor determines in the comparison that the total time to dispatchable load is outside of the predetermined period of the current time to the target time, and repeating steps d to h.

17. The control system of claim 16 wherein the database includes data for temperatures of a rotor of the steam turbine at a start of each of a plurality of startup processes, and step e includes accessing the database using the estimated rotor temperature to identify one or more prior startup processes having a rotor temperature at the start of the startup process the same as or similar to the estimated rotor temperature, and using the identified one or more prior startup processes to determine the estimated time period for a startup process.

18. The control system of claim 16 wherein the gas turbine is a plurality of gas turbines and the steam turbine is a plurality of steam turbines, and wherein current temperature of the steam turbine is the current temperature of one of the plurality of steam turbines.

19. The control system of claim 16 wherein the steps d to h are repeated until the comparison determines the total time to dispatchable load is within the predetermined period of the current time to the target time.

20. The control system of claim 16 wherein the step d includes using an electronic model of a steam turbine which receives as inputs the current temperature and a period between the current time and the forecasted start time and outputs the estimated rotor temperature at the forecasted start time.