Design of main steam temperature control system of sub-critical 600MW power unit and its application

This paper presents a control system design scheme which combined the State Feedback based on the Increment Function Observer with PID, this design scheme has been successfully applied to a 600 MW boiler super-heater steam temperature control system. The control system could be in automation mode continually while the unit quickly changed its load up to 375 MW in succession, and it was taking an excellent control result which the biggest errors of two side main steam temperatures were less than 8degC and 10degC respectively. This case shows the theory of Increment Function Observer can be applied successfully in the thermal control engineering field, it provides an example for solving the control issue of the great inertia and the larger time lag controlled object such as boiler super-heater steam temperature control.