Design And Realization Of Superheated Steam Temperature Internal Mode Control For 600MW Thermal Power Unit

Superheated steam temperature is an important indicator of safe and economic performance in thermal power unit, a series of safety problems may be caused by too high or too low superheated steam temperature. Since the superheated steam temperature with nonlinear, time varying, multiple disturbance factors, affected by coal and other characteristics, the current superheated steam temperature control is still the difficulty of thermal process control, the superheated steam temperature deviates from the set value is often too big during a wide process change of unit load. Therefore it is necessary to propose a superheated steam temperature optimal control strategy, to meet different load and large disturbances conditions, which can improve the level of superheated steam temperature control in coal-fired units.Aiming at the superheated steam temperature system of 600MW power unit in Jinglong Power Plant, models of three typical operating points are formulated through the experimental data in the corresponding typical operating points. Considering the dynamic characteristics of superheated steam temperature with large delay and model parameters varying following the unit load, a compound control strategy which includes internal model control, multi-model control and feedforward compensate control is proposed. This control strategy is successfully applied to NO.1 Unit in Jinglong Power Plant. The run results show that the proposed control strategy can ensure the superheated steam temperature running within a satisfactory range under the conditions of either load stable process or load varying process.