Under the background of the new power system

in the process of deep peak regulation and rapid load change of coal-fired units

the combustion stability of the boiler decreases

the hydrodynamic power is insufficient

and the radiation/convection heat transfer characteristics are migrated

resulting in the uneven spatial and temporal distribution of heat in the furnace. Based on the in-depth analysis of the operation characteristics of the steam-water system

the variational mode decomposition method is used to extract the operating characteristics of the steam temperature at all levels

and the optimal fixed values of the steam temperature at all levels are obtained through the calculation of forward and reverse cruise values. On this basis

a multi-stage linkage control system of main steam temperature grounded on constant cruise control is designed. The simulation results show that

compared with the manual adjustment of the traditional operator

the system has a reasonable cruising time and correct cruising direction

and can intelligently adjust the steam temperature instead of the operator. The practical application of the 1 000 MW ultra- supercritical unit shows that the system can adapt to the complex and changeable operating environment on site

and in the process of deep peak regulation and rapid load change of the unit

it can realize the automatic cruise of steam temperature and the operation personnel without intervention throughout the whole process

effectively reduce the labor intensity

and possess a good engineering application prospect.