Gas turbine control method and gas turbine power generating apparatus

1. A gas turbine control method for a gas turbine that includes a combustor and a plurality of nozzle groups grouped into a first main nozzle group and a second main nozzle group so as to be arranged on the circumference of a pilot nozzle, each of the first main nozzle group and the second main nozzle group having different numbers of main nozzles and supplying fuel gas to the combustor, and that switches the first main nozzle group and the second main nozzle group used for fuel supply according to an operating condition, the method comprising the steps of:

receiving the operating condition from the gas turbine and calculating at least a first adjustment parameter, a second adjustment parameter and a third adjustment parameter from the operating condition;

registering in advance at least the first adjustment parameter selected from a fuel-supply sharing ratio of the first main nozzle group with respect to a fuel supply command value, at least the second adjustment parameter selected from a fuel-supply sharing ratio of the second main nozzle group with respect to the fuel supply command value, and at least the third adjustment parameter selected so as to adjust at least one of the fuel-supply sharing ratio of the first main nozzle group and the fuel-supply sharing ratio of the second main nozzle group in a main nozzle group switching period, during which the first main nozzle group that has been used is switched to the second main nozzle group that is going to be used;

determining a fuel supply command value of the first main nozzle group and a fuel supply command value of the second main nozzle group during the main nozzle group switching period using the fuel-supply sharing ratio of the first main nozzle group, the fuel-supply sharing ratio of the second main nozzle group, and the first, second and third adjustment parameters;

updating the first, second and third adjustment parameters registered in advance, according to the operating condition of the gas turbine in which a fuel control based on the determined fuel supply command value of the first main nozzle group and the fuel supply command value of the second main nozzle group are reflected; and

registering the updated adjustment parameters as adjustment parameters to be used next.

2. A gas turbine control method for a gas turbine according to claim 1 , wherein, at least the first, second and third adjustment parameters adjust at least one of the fuel-supply sharing ratio of the first main nozzle group and the fuel-supply sharing ratio of the second main nozzle group so that a total amount of the fuel supply command value of the first main nozzle group and the fuel supply command value of the second main nozzle group are larger than the fuel supply command value.

3. A gas turbine control method for a gas turbine according to claim 1 , wherein at least the first, second and third adjustment parameters are updated based on information about a gas-turbine output or a gas-turbine rotation speed.

4. A gas turbine control method for a gas turbine according to claim 1 , wherein whether to permit update of the first, second and third adjustment parameters is determined based on the operating condition of the gas turbine, and update registration of the first, second and third adjustment parameters is performed based on the determination result.

5. A gas turbine control method for a gas turbine according to claim 1 , wherein one of the first, second and third adjustment parameters that is used to determine a decrease start timing of the fuel supply command value of the first main nozzle group in the nozzle switching period.

6. A gas turbine control method for a gas turbine according to claim 1 , wherein one of the first, second and third adjustment parameters is used to determine a rate of increase for at least one of the fuel supply command value of the first nozzle group and the fuel supply command value of the second nozzle group.

7. A gas turbine control method for a gas turbine according to claim 1 , wherein one of the first, second and third adjustment parameters is used to determine at least one of a rate of change of increase for the fuel supply command value of the second nozzle group and a rate of change of decrease for the fuel supply command value of the first nozzle group.

8. A gas turbine control method for a gas turbine according to claim 1 , wherein, when there are a plurality of adjustment parameters, the nozzle switching period is divided into a plurality of time periods according to the properties of at least the first, second and third adjustment parameters, at least the first, second and third adjustment parameters are respectively allocated to the time periods, and at least each of the first, second and third adjustment parameters is updated according to the operating condition of the gas turbine in the time period to which it is allocated.

9. A gas turbine control method for a gas turbine according to claim 1 , wherein at least the first, second and third adjustment parameters are updated based on at least one of atmospheric conditions, start-up conditions, power-plant operating conditions, and power-plant operational states, in the nozzle switching period, and the updated adjustment parameters are registered as the adjustment parameters to be used next.

10. A gas turbine power generating apparatus that includes a combustor and a plurality of nozzle groups grouped into a first main nozzle group and a second main nozzle group so as to be arranged on the circumference of a pilot nozzle, and the each of the first main nozzle group and the second main nozzle group having different numbers of main nozzles and supplying fuel gas to the combustor and that switches the first main nozzle group and the second main nozzle group used for fuel supply according to an operating condition, comprising:

a parameter setting section that receives the operating condition from the gas turbine and calculates at least a first, second and third adjustment parameters from the operating condition; said parameter setting section adjusts at least the first adjustment parameter selected from a fuel-supply sharing ratio of the first main nozzle group with respect to a fuel supply command value, at least the second adjustment parameter from a fuel-supply sharing ratio of the second main nozzle group with respect to the fuel supply command value, and at least the third adjustment parameter selected so as to adjust at least one of the fuel-supply sharing ratio of the first main nozzle group and the fuel-supply sharing ratio of the second main nozzle group in a main nozzle group switching period during which a first main nozzle group that has been used is switched to a second main nozzle group that is going to be used;

a determining section for determining a fuel supply command value of the first main nozzle group and a fuel supply command value of the second main nozzle group during the main nozzle group switching period using the fuel-supply sharing ratio of the first main nozzle group, the fuel-supply sharing ratio of the second main nozzle group, and at least the first, second and third adjustment parameters; and

an adjustment parameter update registration section that updates at least the first, second and third adjustment parameters according to the operating condition of the gas turbine in which a fuel control based on the determined fuel supply command value of the first main nozzle group and the fuel supply command value of the second main nozzle group are reflected, and that registers the updated adjustment parameters in the parameter setting section as adjustment parameters to be used next,

wherein the gas turbine power generating apparatus allows a fluctuation in output of the gas turbine to be reduced.