Control system and method for controlling a gas turbine in accordance with the temperature conditions thereof

• US 4,455,820 A
• Filed: 09/09/1976
• Issued: 06/26/1984
• Est. Priority Date: 09/09/1976
• Status: Expired due to Term

• Current Assignee: General Electric Company
• Original Assignee: General Electric Company
• Inventors: Wong, Thomas Y., Russell, John N., Chausse, Burnette P., Buckley, Leo P. Jr., Chen, Arthur C.
• Primary Examiner(s): Casaregola, Louis J.
• Application Number:
  US05/721,998
• Time in Patent Office: 2,847 Days
• Field of Search: 60/39.28 T, 60/39.28 R, 60/39.03, 73/116, 73/341
• US Class Current: 60/773
• CPC Class Codes: F02C 9/28 Regulating systems responsive to plant or ambient parameters, e.g. temperature, pressure, rotor speed F02C9/30 - F02C9/38, F02C9/44 take precedence
• CPC Class Codes: F05D 2270/303 Temperature

Abstract

A control system including a controller for reading temperature values from sensors in a gas turbine, determining the reliability of the sensors, and issuing a fuel control signal for use in controlling the turbine is disclosed. The fuel control signal has a calculated value which is a function of the turbine operating temperature derived from the values of temperature signals generated by the sensors.

Claims

1. A system for controlling fuel flow to a gas turbine in accordance with turbine temperature represented by the values of temperature readings provided by temperature sensors in the turbine, said system comprising:

(a) a programmable controller for providing a temperature trim signal including,

(1) a storage means for retaining a program of instructions and holding data related to the calculation of said temperature trim signal,

(i) certain ones of said instructions directing said controller to determine if the value of each temperature reading is within prescribed limits and to reject those readings which are out of limits,

(ii) certain other ones of said instructions directing said controller to calculate the value of said temperature trim signal for output by said controller only when a specified number of unrejected temperature readings are within said prescribed limits, said temperature trim signal, when present, having a value proportional to the difference between a mid-value signal applied to said controller and a calculated value proportional to the average of unrejected temperature readings, and

(2) means in communication with said storage means for executing said instructions and processing said data;

(b) a signal source for generating a reference signal proportional to a safe turbine operating temperature; and

,

(c) analog control means for providing a fuel control signal including,

(1) means coupled to specified ones of said temperature sensors for providing said mid-value signal to said controller, said mid-value signal having a magnitude intermediate the individual values of the temperature readings provided by said specified ones, and

(2) combining means for providing said fuel control signal, said combining means responsive to said temperature trim signal, said mid-value signal and said reference signal to provide said fuel control signal when said temperature trim signal is present at the output of said controller, and further responsive to said mid-value signal and said reference signal to provide said fuel control signal in the absence of said temperature trim signal;

(d) means for transferring the temperature readings to said controller from said temperature sensors; and

(e) means for delivering said fuel control signal from said analog means to said gas turbine for controlling fuel flow thereto.

2. The system in accordance with claim 1 wherein the number of unrejected readings and the sum of the unrejected readings are stored as numerical values in respectively specified locations in said storage means and wherein said program of instructions includes means for directing said controller to access said locations to calculate the value proportional to the average of the unrejected temperature readings.

3. The system in accordance with claim 1 wherein said combining means comprises a summation means responsive to the signals applied thereto for providing said fuel control signal and wherein the magnitude of said fuel control signal is proportional to the algebraic sum of the signals applied thereto.

4. The system in accordance with claim 1 wherein said means for providing said mid-value signal comprises a selector circuit whereby said mid-value signal has a first value intermediate the individual values of the temperature readings of said specified ones when a minimum number of the temperature readings of said specified ones are within prescribed limits and having a second value when less than said minimum number of temperature readings of said specified ones are out of said limits.

5. The system in accordance with claim 1 wherein said temperature trim signal has a value of zero representing its absence when a predetermined number of temperature readings are rejected and has a value, in its presence, proportional to turbine operating temperature derived from the average of the unrejected temperature readings.

6. The system in accordance with claim 4 wherein said analog control means further includes means for providing a trip signal to said turbine to shut off fuel flow thereto in response to said mid-value signal achieving said second value.

7. In a control system, a method of controlling fuel flow to a gas turbine in accordance with turbine temperature represented by the values of temperature readings provided by temperature sensors in the turbine comprising the steps of:

(a) providing a mid-value signal having a magnitude intermediate the values of the temperature readings provided by specified ones of said temperature sensors;

(b) generating a reference signal proportional to a safe turbine operating temperature;

(c) providing a computer having storage means retaining a program of instructions and holding data related to the calculation of a temperature trim signal for output by said computer,

(1) certain ones of said instructions directing said computer to determine if the value of each temperature reading is within prescribed limits and to reject those temperature readings which are out of limits,

(2) certain other ones of said instructions directing said computer to calculate the value of said temperature trim signal only when a specified number of unrejected temperature readings are within said prescribed limits, said temperature trim signal, when present, having a value proportional to the difference between said mid-value signal and a calculated value proportional to the average of the unrejected temperature readings;

(d) combining said temperature trim signal, said mid-value signal and said reference signal to generate a fuel control signal, said fuel control signal having a value proportional to the algebraic sum of the temperature trim, mid-value and reference signals when said temperature trim signal is present and further having a value proportional to the algebraic sum of the mid-value and reference signals in the absence of said temperature trim signal; and

,

(e) delivering said fuel control signal to said gas turbine to control fuel flow thereto.

8. A system for controlling fuel flow to a gas turbine in accordance with turbine temperature represented by the values of temperature signals generated by sensors in the turbine, said control system comprising:

(a) a controller in communication with the turbine for receiving the temperature signals and generating a temperature trim signal, said controller including,

(1) first means responsive to the temperature signals to selectively determine the reliability of each of the sensors to allow at the output thereof only those temperature signals having a magnitude within specified limits.

(2) first averaging means for generating a first output signal having a value proportional to the average values of the temperature signals at the output of said first means,

(3) means for generating a first reference signal having a value proportional to a maximum permissible deviation of the magnitude of any temperature signal from a prescribed value,

(4) means for algebraically combining said first output signal and said first reference signal to develop a second reference signal proportional to said prescribed value,

(5) second means responsive to said second reference signal and to all temperature signals to reject each sensor whose temperature signal deviates from the value of said second reference by a prescribed amount and to allow at the output of said second means the temperature signals of all unrejected sensors,

(6) second averaging means for generating a second output signal having a value proportional to the average of the values of the temperature signals at the output of said second means,

(7) means for generating a third reference signal having a value proportional to a desired turbine operating temperature,

(8) means responsive to said second output signal, said third reference signal and those temperature signals at the output of said second means for generating said temperature trim signal only when a specified number of reliable sensor temperature signals are passed by said second means, said temperature trim signal, when present, having a value proportional to the difference in magnitude between said second output signal and said third reference signal;

(b) a signal source for generating a fourth reference signal proportional to a safe turbine operating temperature;

(c) backup means for generating a fuel control signal including,

(1) means coupled to specified ones of the sensors for generating a mid-value signal having a magnitude substantially intermediate the individual values of the temperature signals generated by said specified one, and

(2) combining means responsive, when said temperature trim signal is present at the output of said controller, to said temperature trim signal, said mid-value signal and said fourth reference signal to provide said fuel control signal, and further responsive to said mid-value signal and said fourth reference signal, in the absence of said temperature trim signal, to provide said fuel control signal; and

,

(d) means for delivering said fuel control signal to said turbine to control fuel flow thereto.

9. A control system for controlling fuel flow to a gas turbine in accordance with turbine temperature represented by the values of temperature signals generated by sensors in the turbine, said control system comprising:

(a) a signal source for generating a first reference signal proportional to a safe turbine operating temperature;

(b) analog control means for providing a fuel control signal to said gas turbine including,

(1) means coupled to specified ones of said sensors for generating a mid-value signal having a magnitude intermediate the individual values of the temperature signals generated by said specified ones, and

(2) combining means, said combining means responsive to a temperature trim signal, said mid-value signal and said first reference signal to provide the fuel control signal to said gas turbine when said temperature trim signal is present and further responsive to said mid-value signal and said reference signal, in the absence of said temperature trim signal, to provide the fuel control signal to said gas turbine;

(c) means for providing a second reference signal proportional to a desired turbine operating temperature; and

,

(d) a programmable controller responsive to the first reference signal, the mid-value signal, the second reference signal and the temperature signals, said controller including a storage means for retaining a program of instructions and holding data related to the calculation of said temperature trim signal for output by said controller,

(1) certain ones of said instructions directing said controller to determine the reliability of each sensor by rejecting each sensor whose temperature signal is outside specified limits, and

(2) certain other ones of said instructions directing said controller to calculate the value of the temperature trim signal for output to said combining means only when a specified number of sensors are determined to be reliable, said temperature trim signal, when present, having a calculated value derived from the sum of the difference in magnitude between the first reference signal and said second reference signal and the difference in magnitude between the mid-value signal and a calculated value which is a function of the turbine operating temperature derived from the values of the temperature signals of the sensors determined to be reliable.

10. In a control system, a method of controlling the operating temperature of a gas turbine in accordance with turbine temperature represented by the values of temperature signals generated by sensors in the turbine, comprising the steps of:

(a) generating a first reference signal proportional to a safe turbine operating temperature;

(b) providing a second reference proportional to a desired turbine operating temperature;

(c) generating a mid-value signal having a value intermediate the individual values of specified ones of the sensor generated temperature signals;

(d) storing in a computer a program of instructions and data related to the calculation of a temperature trim signal for output by said computer,

(1) certain ones of said instructions directing said computer to determine the reliability of each sensor by rejecting each sensor whose temperature signal is outside specified limits, and

(2) certain other ones of said instructions directing said computer to calculate the value of the temperature trim signal for output by said computer only when a specified number of sensors are determined to be reliable, said temperature trim signal, when present, having a calculated value derived from the sum of the difference in magnitude between the first reference signal and said second reference and the difference in magnitude between the mid-value signal and a calculated value which is a function of the turbine operating temperature derived from the values of the temperature signals of the sensors determined to be reliable; and

(e) combining said temperature trim signal, said mid-value signal, and said first reference signal to provide a fuel control signal, said fuel control signal having a value representative of the algebraic sum of the temperature trim signal, the mid-value signal and the first reference signal when said temperature trim signal is present and further having a value representative of the algebraic sum of the mid-value signal and the first reference signal in the absence of said temperature trim signal.