Feasibity Analysis And Research On Control Methods For Fast Cut Back Of Thermal Power Units

Due to the structure of power grid,snow disasters,earthquakes,typhoons,otherharsh natural environment,human error and other factors,power blackouts befallfrequently.The technology of fast cut back can restore power quickly after powerblackouts, guarantee the safe operation of the units,at the same time, provide startuppower for other thermal power units, reduce the losses greatly caused by theaccident,however,thermal power units in China rarely have this feature,so thetechnology is a problem to be solved.At present,the research of this direction is theuse of the experimental method,field test will lead to energy loss,equipmentdamage,test failure risks,conclusions limitations and other issues. With thedevelopment of domestic and international thermal system simulation technology, theuse of modelling and simulation methods can solve these problems.The research ofsimulation technology for thermal power units is focused on conventionalconditions,there is no research on FCB by modelling and simulation.In this paper, the use of modelling and simulation technology, according to thespecific purpose of simulation modelling,the paper created the models of mainoperating parameters of boiler based on mechanism,and carried out simulation testsfor FCB,obtained the dynamic characteristics of pressure of main steam,temperatureand drum level during the initial stage of FCB,studied the influence of characteristicsof related equipment on the dynamic characteristic,put forward control measures ofmain steam pressure,analyzed the feasibility of FCB of thermal power units withdifferent bypass;created the model of the temperature of boiler furnace by layeredmodelling,put forward evaluation of temperature change during stopping mills,putforward the measure of stopping mills during FCB based the evaluation;establishedthe model of feed water pump turbine regulating system,researched the process ofswitching of feed water pump turbine steam source based on the model,put forwardthe measures of feedwater control during FCB.