Abstract: Taking the variable frequency reformation of induced draft fans of units No.1 and No.3 in Guizhou Dafang Power Generation Company Limited as examples, the optimization of the thermal control logic for variable frequency reformation of induced draft fan was introduced. For the switchover onto 50Hz power supply from converter fault, a set of automatic bypass control logic was designed. The hot state test and the operation effect show that the designed control logic can control the furnace pressure well during state switchover process.

Key words: induced draft fan, variable frequency reformation, control logic, automatic bypass, optimization