Modeling and Simulation of MGT-70 Gas Turbine start-up procedure

In this paper, the transient behavior of heavy duty gas turbines in the starting regime is analyzed and its characteristics are evaluated. Starting a gas turbine is quasi-transient process. So, the integral form of unsteady conservation equations and the ideal gas state equation are used in order to model the system. A new method is proposed to analyze the compressor performance of gas turbine during start-up condition. Compressor stages are grouped into three categories (front, middle, rear), which each of them have a different performance curve in low-speed. Also, the effects of the inter-stage bleed valves modulation are investigated. Finally, the dynamic behavior of a 160 MW MAPNA gas turbine is simulated during start-up condition. The simulation results are compared with the field data and a good agreement is between them. This research has shown the important rule of an exact estimation of start-up procedure (fuel, blow off valves, power of starter motor) for stable operation of compressor and, eventually, of the gas turbine.