After ultra-low emission transformation

the combustion characteristics of No.2 boiler of Huanggang Dabieshan Power Generation Company Ltd changed. The original automatic control logic and parameters can't meet the requirements of the power grid. Moreover

the outlet wall temperature of platen superheater of unit 2 was over temperature in the low and medium load section. Meanwhile

the main steam pressure

main steam temperature

reheat steam temperature and other main parameters of the unit fluctuated greatly in the process of load change

resulting in low load change rate of the unit

which was only 3.5 MW/min

which could not meet the relevant provisions of the power grid. In this regard

on the premise of no locomotive renovation

multi variable cooperative control was used to optimize the sliding pressure curve

modify the primary air pressure setting curve

oxygen setting curve

intermediate point temperature setting curve and air coal ratio setting function

redesign the automatic control strategy

and dynamically control the fuel volume

water supply flow and total air volume entering the furnace. After optimization

the actual load change rate of unit 2 under AGC mode reaches 9 MW/min

and the main parameters change smoothly

which solves the problem of wall temperature over temperature at the outlet of platen superheater.