Turbine Model Improvement for a Heavy-Duty Gas Turbine Plant Simulation

The interest of the world electricity market in the gas turbine and the gas-steam combined cycles has given a significant stimulus to the development of numerical simulations, useful in the detailed analyses of dynamic behaviour and off-design performance of the gas plant. This paper describes the latest improvements of a physical simulator built to predict the off-design and dynamic behaviour of single shaft, heavy-duty gas turbine plants. The analysis has been applied to the V94.2 and V64.3 models of the Ansaldo Energia production, that feature a compressor equipped with variable inlet guide vanes and an air bleed system cooled turbine. The mathematical model is non linear, based on the lumped parameter approach and described by a set of differential and algebraic equations. In particular, the next version presents a turbine model entirely rebuilt, based on a simplified, one-dimensional row by row calculation method. The equations system and the structure of the new code are here described, and the steady-state results of the dynamic model are compared with the results of an Ansaldo static code with a good correspond in the performance prediction. The model has been developed in the Matlab-Simulink^® environment using some FORTRAN subroutines.