Turbine start-up algorithm based on prediction of rotor thermal stress

This paper presents a control algorithm for a time-optimal control of a thermal power plant based on predictive control. In a thermal power plant the temperature between the hot steam and the cold rotor causes the thermal stress. The excess thermal stresses shorten the life span of the steam turbine rotor and restrict the start up time of the plant. The control algorithm designed by a model predictive control method calculates the optimal future profile of the steam flow rate at every control interval. The actual steam flow rate is controlled to the optimal profile which enables start up of the turbine in the shortest period keeping the thermal stress under the allowable value. Numerical examples show the effectiveness of the algorithm.