Turbine Control System Based on Prediction of Rotor Thermal Stress

A turbine automatic control system, designated HITASS (Hitachi Turbine Automatic Startup System), has been developed, which is capable of predicting thermal stress in the turbine rotors. HITASS uses an auto- regressive dynamics model to predict the boiler outlet steam conditions which are used as the basis for calculating thermal stress. It then carries out on-line optimization of acceleration rate and load variation rate in accordance with the predicted thermal stress. By using simulation techniques, it has been proved that HITASS makes possible a 25% reduction in startup time and a 30% improvement in load following performance as compared with the conventional off-line schedule control system. HITASS uses a HIDIC-08 microcomputer. The system has already been applied to a number of power plants with good operational results.