Implementation of Optimal Control at a Supercritical Variable-Pressure Thermal Power Plant

Abstract Optimal steam-temperature control of a supercritical variable-pressure type thermal power plant is presented with emphasis on the actual procedure of controller design. A control system based on Linear Quadratic Regulator Theory is employed. After an introduction on the special features of variable-pressure boiler control, the concept of control system and some results of the preliminary study on a digital simulation model are described. Then, the LQ regulator implemented at a 500MW plant is introduced with some field test results which confirm the advantages of the optimal controller over the conventional PID controller. The results of this investigation revealed that the optimal control system, which has been successfully in routine operation at the constant-pressure plants is also effective for improving variable-pressure boiler control.