In order to investigate the dynamic characteristics of main steam pressure at the beginning of fast cut back(FCB)

the model of the steam water system for a 300 MW unit was established.Moreover

on the basis of this model

FCB simulation test under 100%load condition was conducted.The results show that:the pressure control effect of small capacity high pressure bypass equipped with pressure control valve(PCV)was better than that of the large capacity bypass;reducing the early high pressure bypass valve open time was effective for main steam pressure control during initial FCB;the unit with total pressure relief volume from high pressure bypass and PCV less than 65%BMCR was not suitable for carrying out FCB.