Fuel control method for gas turbine, control device for executing said method, and gas turbine installation provided with said control device

Patent metadata

Field	Value
Publication number	US-10815905-B2
Application number	US-201515305484-A
Country	US
Kind code	B2
Filing date	Apr 30, 2015
Priority date	May 26, 2014
Publication date	Oct 27, 2020
Grant date	Oct 27, 2020

Abstract

A control device includes a fuel equivalent value calculation unit for determining the flow rate of fuel supplied to a gas turbine in accordance with a target value deviation between an actual rotation speed and a target rotation speed, an upper limit deviation calculation unit for obtaining an upper limit deviation which is a deviation between a set upper limit output and an actual output, a lower limit deviation calculation unit for obtaining a lower limit deviation which is a deviation between a set lower limit output and the actual output, and a parameter-changing unit for changing any one parameter among the target rotation speed, the actual rotation speed, and the target value deviation so that the target value deviation decreases when the actual rotation speed decreases and the upper limit deviation is small, and so that the target value deviation increases when the actual rotation speed increases and the lower limit deviation is small.

First claim

The invention claimed is:

1. A control device for a gas turbine comprising: the control device configured to:
output a target value that is equivalent to a target rotation speed of the gas turbine;
obtain a target value deviation, the target value deviation being a deviation of the target value with respect to an actual rotation speed equivalent value that is equivalent to an actual rotation speed of the gas turbine;
detect a variation of the actual rotation speed of the gas turbine, wherein the variation is between a first actual rotation speed and a second actual rotation speed after a delay of a predetermined period of time, and output an indication of whether the actual rotation speed equivalent value has increased or decreased in accordance with the variation:
obtain an upper limit deviation, the upper limit deviation being a deviation of a set upper limit output of the gas turbine with respect to an actual output of the gas turbine;
obtain a lower limit deviation, the lower limit deviation being a deviation of the actual output of the gas turbine with respect to a set lower limit output of the gas turbine; and-
change any one of the target value, the actual rotation speed equivalent value, and the target value deviation such that
the target value deviation decreases in a case where the actual rotation speed equivalent value has decreased when the upper limit deviation is smaller than a first previously determined value, and
the target value deviation increases in a case where the actual rotation speed equivalent value has increased when the lower limit deviation is smaller than a second previously determined value;
and determine a fuel equivalent value that is equivalent to a flow rate of fuel supplied to the gas turbine in accordance with the target value deviation such that
the fuel equivalent value decreases and the actual output of the gas turbine remains below the set upper limit output in a case where the target value deviation decreases,
and the fuel equivalent value increases and the actual output of the gas turbine remains above the set lower limit output in a case where the target value deviation increases.

2. The control device for the gas turbine according to claim 1 , wherein changing said any one of the target value, the actual rotation speed equivalent value, and the target value deviation includes:
correcting a proportional gain by decreasing the proportional gain in the case where the actual rotation speed equivalent value has decreased when the upper limit deviation is smaller than the first previously determined value, and increasing the proportional gain in the case where the actual rotation speed equivalent value has increased when the lower limit deviation is smaller than the second previously determined value;
multiplying the target value deviation by the corrected proportional gain to obtain a corrected target value deviation; and
outputting the corrected target value deviation as the fuel equivalent value.

3. The control device for the gas turbine according to claim 1 , wherein outputting the target value includes:
limiting a target output of the gas turbine by outputting, as a limited target output, a smaller one of
(a) a larger one of (i) a previously received target output of the gas turbine and (ii) the set lower limit output and (b) the set upper limit output,
obtaining an output deviation, the output deviation being a deviation of the limited target output with respect to the actual output of the gas turbine, and
obtaining the target value that is equivalent to the target rotation speed of the gas turbine based on the output deviation.

4. The control device for the gas turbine according to claim 3 , wherein obtaining the target value includes:
obtaining the target value in accordance with the output deviation by using an arbitration rate showing a rotation speed-output relationship.

5. The control device for the gas turbine according to claim 1 , wherein the control device is further configured to:
create a valve opening degree command in accordance with the decreased fuel equivalent value that is determined in accordance with the decreased target value deviation, or in accordance with the increased fuel equivalent value that is determined in accordance with the increased target value deviation;
and output the valve opening degree command to a fuel regulation valve that regulates the flow rate of the fuel supplied to the gas turbine to stabilize the actual rotation speed of the gas turbine.

6. A gas turbine installation comprising:
the control device for the gas turbine according to claim 5 ;
the fuel regulation valve; and
the gas turbine.

7. The control device for the gas turbine according to claim 1 , wherein changing said any one of the target value, the actual rotation speed equivalent value, and the target value deviation includes:
correcting the target value such that the target value decreases in the case where the actual rotation speed equivalent value has decreased when the upper limit deviation is smaller than the first previously determined value, and the target value increases in the case where the actual rotation speed equivalent value has increased when the lower limit deviation is smaller than the second previously determined value;
multiplying the target value deviation by a proportional gain to obtain a corrected target value deviation, the target value deviation being a deviation of the corrected target value with respect to the actual rotation speed equivalent value; and
outputting the corrected target value deviation as the fuel equivalent value.

8. The control device for the gas turbine according to claim 1 , wherein changing said any one of the target value, the actual rotation speed equivalent value, and the target value deviation includes:
correcting the actual rotation speed equivalent value such that the actual rotation speed equivalent value decreases in the case where the actual rotation speed equivalent value has decreased when the upper limit deviation is smaller than the first previously determined value, and the actual rotation speed equivalent value increases in the case where the actual rotation speed equivalent value has increased when the lower limit deviation is smaller than the second previously determined value;
multiplying the target value deviation by a proportional gain to obtain a corrected target value deviation, the target value deviation being a deviation of the target value with respect to the corrected actual rotation speed equivalent value; and
outputting the corrected target value deviation as the fuel equivalent value.

9. A fuel control method for a gas turbine comprising:
outputting a target value that is equivalent to a target rotation speed of the gas turbine; obtaining a target value deviation, the target value deviation being a deviation of the target value with respect to an actual rotation speed equivalent value that is equivalent to an actual rotation speed of the gas turbine;
detecting a variation of the actual rotation speed of the gas turbine, wherein the variation is between a first actual rotation speed and a second actual rotation speed after a delay of a predetermined period of time, and outputting an indication of whether the actual rotation speed equivalent value has increased or decreased in accordance with the variation;
obtaining an upper limit deviation, the upper limit deviation being a deviation of a set upper limit output of the gas turbine with respect to an actual output of the gas turbine;
obtaining a lower limit deviation, the lower limit deviation being a deviation of the actual output of the gas turbine with respect to a set lower limit output of the gas turbine;
and changing an

Assignees

• Mitsubishi Hitachi Power Sys

Inventors

• Suzuki Hiroki
• Takata Yasutsugu
• Nakanishi Yoshiaki
• Murakami Masayuki

Classifications

• F05D2270/701

  proportional · CPC title

• F05D2270/022

  to prevent underspeed · CPC title

• F05D2270/021

  to prevent overspeed · CPC title

• F05D2270/024

  to keep rotational speed constant · CPC title

• F02C9/32

  characterised by throttling of fuel (F02C9/38 takes precedence) · CPC title