Sustainable development of energy and high quality development of national economy have made deep peak shaving an indispensable part of thermal power generation technology. The characteristics of large furnace and low mass flow rate of supercritical lignite boiler are disadvantageous to ensure sufficient cooling of water wall and stable flow at low load. In order to ensure safe and stable operation of the furnace during deep peak load and improve the economy of unit peak shaving operation of a supercritical 660 MW lignite boiler

the method of equating the water wall flow network system to three types of components(flow loop

pressure node and connecting pipe) is adopted. According to the conservation law followed by nodes and loops

the accuracy of the model is verified by comparing the calculated results with the measured data of the actual furnace at 648 MW

and the hydrodynamic safety parameters of the water wall at 198 MW(30% BMCR) in the furnace depth peak shaving are analyzed. The calculation results show that

at 198 MW

the maximum mass flow deviation of the furnace under the water wall is 3.03%

that of the upper furnace is 13.66%

the maximum deviation of steam temperature of the upper and lower furnaces is 9.6 ℃ and 9.7 ℃

and the highest outer wall temperature is 473.8 ℃. Both the temperature deviation and the highest outer wall temperature are within a reasonable range

so the safety of hydrodynamic operation under 30% BMCR deep peak load regulation is realized

and the flow stability characteristics are good. It is of great significance to lignite boilers for further breaking through the limit of the lowest start-up load during deep peak regulation.