Patent ID: 7707814

Claim:
A fuel-flow-rate control device for controlling a fuel flow rate supplied to a combustor of a gas turbine including a compressor configured to compress and emit air, the combustor configured to burn a fuel supplied via a fuel pipe together with the compressed air supplied from the compressor and to emit a combustion gas, a turbine to be driven by the combustion gas supplied from the combustor, and a power generator configured to be driven by the turbine, said fuel-flow-rate control device comprising: a computing portion configured to obtain a state quantity corresponding to operating conditions and temperature conditions of the gas turbine as an input signal, and to compute a fuel-flow-rate command for controlling the fuel flow rate supplied to the combustor; and a regulating portion configured to set the fuel-flow-rate command obtained by said computing portion to be no greater than a fuel-flow-rate upper limit, the fuel-flow-rate upper limit being set to a fuel flow rate at which an inlet temperature of the turbine is set to be not more than a predetermined upper temperature limit; wherein said computing portion includes: a load controller configured to calculate a load control signal for controlling the fuel flow rate so that an output of the power generator coincides with a target value; an exhaust-gas-temperature controller configured to calculate an exhaust-gas-temperature control signal for controlling the fuel flow rate so that an exhaust gas temperature of the turbine does not exceed an exhaust-gas-temperature upper limit; a blade-path-temperature controller configured to calculate a blade-path-temperature control signal for controlling the fuel flow rate so that a blade path temperature of the turbine does not exceed a blade-path-temperature upper limit; and a selection circuit configured to select a control signal having the lowest value as the fuel-flow-rate command among the load control signal, the exhaust-gas-temperature control signal, and the blade-path-temperature control signal.