Abstract: The working principle of control subsystems of unit No.4 in a certain power plant were introduced, the problems existed in the subsystems were analyzed, and some reasonable, feasible optimizing measures were proposed. After perfecting of control plan and optimization of control parameters, the better adjustment quality of control subsystems was achieved, and the requests of the normal operation, the load variation and the RB test can be satisfied.

Key words: forced draft control, induce draft control, superheated steam temperature, RB test, system optimization