An Optimum Start up Algorithm for Combined Cycle

In combined cycle start up operation, the faster start up while maintaining steam tubine thermal stress under the limitation is requested. This paper presents an optimum start up algorithm for combined cycle, using model predictive control algorithm. The steam temperature inside steam turbine is estimated by using developed simulator, and modeled by ARX method. The Rotor temperature and thermal stress are predicted using the steam temperature ARX model. The gas turbine loading rate is determined by predicting the thermal stress sequentially. The result shows the thermal stress is precisely restrained under the thermal stress limitation while reducing the start up time about an hour from the conventional method.