Gas turbine controller and a method for controlling a gas turbine
View Patent ↗Exemplary embodiments relate to a method and system for transient operating of a gas turbine. Operation of the gas turbine the controller determines command values for an inlet air mass flow, fuel mass flow, and for a water or steam mass flow. In order to allow fast transient operation with a stable premix flame at least one command value is dynamically compensated to compensate for the different system dynamics of the supply systems to synchronize the resulting changes in fuel, water, steam, and/or combustion air mass flows, which reach the combustor, so that the fuel to air ratio stays within the combustible limit.
1. A control system for controlling a gas turbine having
a compressor with variable inlet guide vanes,
a combustor,
a turbine,
a controller, measurement devices, actuators, inlet air supply channels, and supply channels for fuel supply, and water, or steam supply,
wherein each supply channel is associated with a respective supply system, and
wherein the controller determines command values for an inlet air mass flow, fuel mass flow, and water or steam mass flow,
the control system comprising:
a dynamic compensator for the fuel supply, a dynamic compensator for the water or steam supply, and a dynamic compensator for an air supply to the combustor; and
a processor configured to
correct at least one command signal during transient operation to compensate for differences in dynamics of the respective supply system to synchronize resulting changes in the fuel mass flow, the water or steam mass flow, and the inlet air mass flow, which enter the combustor, so that a fuel to air ratio stays within combustible limit,
wherein no dynamic compensation is provided for the command signal for one of the inlet air mass flow, the fuel mass flow, and the water or steam mass flow with a slowest speed of transient change, and
wherein a dynamic compensation is provided for at least one of the inlet air mass flow, the fuel mass flow, and the water or steam mass flow with a faster speed of transient change.
2. The control system according to claim 1 , wherein at least one of the dynamic compensator for the fuel supply, the dynamic compensator for the water or steam supply, and the dynamic compensator for the air supply, comprises an accelerator to moderate slow dynamics of at least one of the inlet air mass flow, the fuel mass flow, and the water or steam mass flow before or after a value is dynamically compensated in order to allow faster transient changes in operation.
3. The control system according to claim 1 in combination with the gas turbine, wherein at least one of the dynamic compensator for the fuel supply, the dynamic compensator for the water or steam supply, and the dynamic compensator for the air supply, comprises a transfer function, which describes dynamics of at least one of the inlet air mass flow, the fuel mass flow, and the water or steam mass flow.
4. The control system according claim 1 , wherein the fuel supply have no dynamic compensator compensation and the air supply includes a dynamic compensation.
5. The control system according to claim 2 , wherein at least one of the dynamic compensator for the fuel supply, the dynamic compensator for the water or steam supply, and the dynamic compensator for the air supply, comprises a transfer function, which describes dynamics of at least one of the the inlet air mass flow, the fuel mass flow, and the water or steam mass flow.
6. The control system according to claim 3 , wherein no dynamic compensation is provided for the fuel supply gas and a dynamic compensation for the air supply is provided.
7. A gas turbine comprising a control system according to claim 1 .