Abstract: The operation of air preheater automatic airleakage control system of the 2×670MW unit in Huadian Weifang Power Generation Corporation Limited project phase II was introduced. Aiming at the problems exposed since it has been put into operation, the automatic airleakage control system had been improved; the air damper compulsively lifting function under the condition of exceed air preheater current was added; the protection signals of maximum distortion and complete reset were doubled redundantly. The reliability of the automatic airleakage control system was enhanced; the air leakage rate was reduced; and the better economical benefit was obtained.

Key words: air preheater, automatic air-leakage control system (LCS), complete reset, maximum distortion, air leakage rate, fault tolerance