Research on Once-Through Steam Generator Steam Pressure Control Strategy

Base on the once-through steam generator model established by the system analysis program, the response characteristics of feedwater flow rate, feedwater temperature and primary side flowrate disturbances are analyzed. The results show that the variation of feedwater flowrate has significant influence on steam pressure and steam temperature, and the variation of primary side flowrate has significant influence on steam temperature. Based on which, the pressure control strategy of once-through steam generator is proposed. The transients such as pressure setpoint step, load step, load ramp and load rejection are simulated to verified the control strategy. In the transients of the fast load ramp and the load rejection, the steam temperature fluctuates greatly. Therefore, a control strategy of correcting steam temperature through primary side flowrate is proposed. The results show that the proposed steam pressure control strategy of once-through steam generator control the steam pressure at the secondary side outlet effectively. At the same time, the steam temperature is within an acceptable operating range by the adjusted primary side flowrate.