After a period of water shortage, Brazil invested in new sources of electricity generation. Natural gas is an example of these new energy sources. Among these plants, some operate with gas turbines. Many studies about gas turbine modeling, performance´s simulation, diagnosis and control have started due the importance of these power plants. Thus, it is necessary that these plants work safely and reliably. To ensure this stability, it is necessary to develop a control system capable of performing this operation for generating electricity in a satisfactory manner. Then, the control system used by this equipment becomes the objective of this study. In this work, a computational model of a gas turbine was used with two main features: a developed computational model of control system based on a new methodology of gas turbine control and an existing thermodynamic model of a gas turbine connected to the Brazilian grid. The control system uses the turbine exhaust temperature (TET) as a corrective factor to adjust the turbine inlet temperature (TIT). TIT was used as a setpoint to control the fuel flow injected inside the combustor. The model also controls the IGV (Inlet Guide Vanes) by a control curve used in control of a specific gas turbine. There is a simplified calculation of the molar composition of the exhaust gas. This feature could be used in combination with a model of a heat recovery steam generator (HRSG) to simulate a condition with duct burners where the main objective is increase the cycle power. The results of simulation were compared to the operational data from the Brazilian power plant.