• control
• identification
• inverse bilinear interpolation
• metering valve
• modeling

The fuel injection system in a gas turbine plant features three branches for injecting fuel into the combustion chamber, each regulated by a metering valve. The three valves work in coordination to ensure that the sum of the flows through each valve always equals 100\%. However, changes in the distribution of flow between the valves, while keeping the total constant, can cause an undesirable increase in turbine speed due to the interaction between the valves and the instantaneous splitting.

This thesis aims to mitigate such fuel overshoot by implementing valve decoupling techniques and bumpless transfer methods. Initially, the dynamics of the valves were identified, analyzing both the relationship between fuel demand and output pressure and the dynamics of the valve actuators. Subsequently, a Simulink model was developed to accurately represent the control system at the turbine inlet, considering the identified valve characteristics, the mathematics for flow calculation, and Woodward maps to determine the effective area.

Once the model was validated, a control system incorporating static and dynamic decouples was implemented. The results demonstrate that these techniques can effectively reduce fuel overshoot, improving the operational stability of the system.

The conclusions of this work provide important insights for optimizing the control of metering valves in twin-shaft turbines, with significant implications for the efficiency and stability of gas turbine systems.