Abstract: The main steam pressure is an important parameter which characterizes the energy supply and demand of supercritical boiler and steam turbine, which is affected largely by the mount of fuel. At present, most fuel coal of thermal power plant is complex, calorific value fluctuates, resulting in the frequent fluctuation of the main steam pressure, seriously affecting the safe operation of the unit. A fuel — main steam pressure ADRC closed loop feedback control loop was designed in the fuel control system, the spontaneous disturbance of coal-fired thermal value was estimated by ESO, which was then real time compensated in the dynamic process, the accuracy of the amount of coal into the furnace was improved, which kept the main steam pressure from fluctuating affected by coal-fired calorific value fluctuations. The design data of a 660 MW ultra—supercritical unit was used to model, compute and simulate, and the results of simulation show that, compared with traditional PID control, ADRC has stronger anti—interference ability and better control quality for main steam pressure.

Key words: main steam pressure, calorific value fluctuation, ADRC, ESO