STUDY OF THE SPEED CONTROL SYSTEM OF A HEAVY-DUTY GAS TURBINE

Gas turbine plays an important role in both the power generation and the frequency regulation of the power grid. In this paper, we have designed a speed control system for the heavy-duty gas turbine. Specifically, the speed control can be organized into four phases, including startup frequency converter (SFC), run-up ramp controller; speed/load controller and grid control center. Firstly, SFC determines the speed during the initial start-up period as the gas turbine and SFC are coaxial. Secondly, after SFC stops, the run-up ramp controller, takes over the speed control until near the rated speed. Then, the speed/load controller is selected by a minimum selector to control the speed of the gas turbine. Finally, after synchronization with the power grid, the speed of the gas turbine depends on the frequency of the grid. In order to study the dynamic characteristics of the speed control system, a model of the gas turbine with its control system has been designed in SIMULINK based on the modular modeling method. The simulation results showed that the transient responses had good performances. So it seems that the speed control system that we designed could regulate the gas turbine during a variable condition.