Control device for gas turbine and control method for gas turbine

1. A control device for a gas turbine,

the gas turbine including:

a compressor configured to compress air supplied from an air supply line;

a combustor configured to receive fuel and burn compressed air compressed by the compressor;

a turbine configured to be rotated by a combustion gas generated in the combustor;

a flue gas discharge line configured to discharge flue gas, the flue gas being the combustion gas that has rotated the turbine; and

a generator configured to generate electric power by being rotated by the turbine,

the control device comprising:

a processor; and

a non-transitory computer-readable medium having stored thereon executable instructions that, when executed by the processor, cause the control device to function as:

a detection value acquisition unit configured to acquire a detection value of at least one of a supply amount of the fuel, pressure of the compressed air, and the electric power generated by the generator;

a flue gas temperature acquisition unit configured to acquire a flue gas temperature detection value representing a detection value of a temperature of the flue gas;

a combustion gas temperature estimate value calculation unit configured to calculate, based on the detection value acquired by the detection value acquisition unit, a combustion gas temperature estimate value representing an estimated temperature of the combustion gas;

a correction term acquisition unit configured to calculate a correction term for correcting the combustion gas temperature estimate value based on a ratio between the combustion gas temperature estimate value and the flue gas temperature detection value;

a corrected combustion gas temperature estimate value calculation unit configured to correct the combustion gas temperature estimate value using the correction term to calculate a corrected combustion gas temperature estimate value; and

a gas turbine controller configured to control the gas turbine based on the corrected combustion gas temperature estimate value.

2. The control device for the gas turbine according to claim 1 , wherein the executable instructions, when executed by the processor, cause the control device to further function as a flue gas temperature estimate value acquisition unit configured to calculate a flue gas temperature estimate value representing an estimated temperature of the flue gas based on the combustion gas temperature estimate value, and

wherein the correction term acquisition unit is configured to calculate the correction term based on a ratio between the flue gas temperature estimate value and the flue gas temperature detection value.

3. The control device for the gas turbine according to claim 2 , wherein the correction term acquisition unit is configured to calculate, as the correction term, the ratio between the flue gas temperature estimate value and the flue gas temperature detection value, and

wherein the corrected combustion gas temperature estimate value calculation unit is configured to multiply the combustion gas temperature estimate value by the correction term to calculate the corrected combustion gas temperature estimate value.

4. The control device for the gas turbine according to claim 3 , wherein the correction term acquisition unit comprises:

a ratio calculation unit configured to calculate the ratio between the flue gas temperature estimate value and the flue gas temperature detection value;

an adjustment coefficient setting unit configured to set an adjustment coefficient for the ratio between the flue gas temperature estimate value and the flue gas temperature detection value to a value larger than 0 and equal to or smaller than 1;

an adjustment ratio calculation unit configured to multiply the ratio between the flue gas temperature estimate value and the flue gas temperature detection value by the adjustment coefficient to calculate an adjustment ratio;

a past adjustment ratio calculation unit configured to multiply a previously calculated correction term by a value obtained by subtracting the adjustment coefficient from 1 to calculate a past adjustment ratio; and

a correction term calculation unit configured to add the past adjustment ratio to the adjustment ratio to calculate the correction term.

5. The control device for the gas turbine according to claim 2 , wherein the flue gas temperature estimate value acquisition unit comprises:

a temporary flue gas temperature estimate value acquisition unit configured to enter the combustion gas temperature estimate value into a predetermined calculation expression defined in advance to calculate a temporary flue gas temperature estimate value; and

a flue gas temperature estimate value calculation unit configured to calculate the flue gas temperature estimate value by performing first-order lag processing of delaying a change with time of a value of the temporary flue gas temperature estimate value.

6. The control device for the gas turbine according to claim 1 , wherein the flue gas temperature acquisition unit is configured to acquire an upstream flue gas temperature detection value and a downstream flue gas temperature detection value, the upstream flue gas temperature detection value representing a temperature of the flue gas at an immediate rear of the turbine, the downstream flue gas temperature detection value representing a temperature of the flue gas on a downstream side of a place where the upstream flue gas temperature detection value is detected,

wherein the executable instructions, when executed by the processor, cause the control device to further function as:

a downstream flue gas temperature estimate value acquisition unit configured to acquire a downstream flue gas temperature estimate value representing an estimate value of the temperature of the flue gas on the downstream side based on the upstream flue gas temperature detection value;

an upstream correction term acquisition unit configured to calculate, based on a ratio between the downstream flue gas temperature detection value and the downstream flue gas temperature estimate value, an upstream correction term for correcting the upstream flue gas temperature detection value; and

a corrected upstream flue gas temperature detection value calculation unit configured to correct the upstream flue gas temperature detection value using the upstream correction term to calculate a corrected upstream flue gas temperature detection value, and

wherein the correction term acquisition unit is configured to use the corrected upstream flue gas temperature detection value as the flue gas temperature detection value to calculate the correction term.

7. The control device for the gas turbine according to claim 1 , wherein the executable instructions, when executed by the processor, cause the control device to further function as a combustion gas temperature comparison value acquisition unit configured to perform a heat balance calculation using the flue gas temperature detection value to calculate a combustion gas temperature comparison value representing the estimated temperature of the flue-combustion gas, and

wherein the correction term acquisition unit is configured to calculate the correction term based on a ratio between the combustion gas temperature estimate value and the combustion gas temperature comparison value.

8. A control method for a gas turbine,

the gas turbine including:

a compressor that compresses air supplied from an air supply line;

a combustor to which fuel is supplied and that burns compressed air compressed by the compressor;

a turbine that is rotated by a combustion gas generated in the combustor;

a flue gas discharge line through which flue gas is discharged, the flue gas being the combustion gas that has rotated the turbine; and

a generator that generates electric power by being rotated by the turbine,

the control method comprising:

acquiring a detection value of at least one of a supply amount of the fuel, pressure of the compressed air, and the electric power generated by the generator;

acquiring a flue gas temperature detection value representing a detection value of a temperature of the flue gas;

calculating, based on the detection value acquired, a combustion gas temperature estimate value representing an estimated temperature of the combustion gas;

calculating a correction term for correcting the combustion gas temperature estimate value based on a ratio between the combustion gas temperature estimate value and the flue gas temperature detection value;

correcting the combustion gas temperature estimate value using the correction term to calculate a corrected combustion gas temperature estimate value; and

controlling the gas turbine based on the corrected combustion gas temperature estimate value.