Regulation and optimization of control strategies for 300 MW CFB boilers

In the operation of some 300 MW CFB boiler, the trip of one ID fan resulted in the rapid change in furnace pressure. Based on the analysis of trip accident, main factors contributing to the fault were analyzed as: over long interlock time of auxiliary machines, irrational instruction limit of gross air flow and failure to trip ID fan etc. Based on the problems reflected by the typical trip, combined with the practical conditions of power units, the control strategies were regulated and optimized, including main protection logic, auxiliary interlock logic, automatic control logic and control methods. The improvements are useful for the safe, stable and economic operation of power units.