Based on the thermodynamic and hydraulic analysis of once-through steam generators and the certain volume of once-through steam generators

the law of conservation of energy and the law of conservation of mass

this paper established pressure control model for once-through steam generators.Moreover

through setting up the pressure once-through steam generator control simulation system using PID controller

this paper verified the model.The results show that

the effects of feed water flow and steam flow in secondary loop on the pressure inside the once-through steam generator were greater than that of the heat transfer of the primary loop.Regardless of non-disturbance or disturbing condition

the control system could make the pressure inside the once-through steam generator reach and stabilize at the set value within400 s

and the maximum overshoot was less than 5%.The pressure dynamic mathematical model of the once-through steam generator could reflect the relationship between the primary coolant temperature

feed water flow

steam flow and the pressure.The pressure cascade control system of the once-through steam generator has fast response speed

small overshoot

strong robustness and anti-interference ability.