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 autoregressive 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.