RB (runback) control method based on forced draft fan system state monitoring for forced draft fan

The invention relates to an RB (runback) control method based on the forced draft fan system state monitoring for a forced draft fan. The RB control method comprises the following steps: judging whether the abnormal working condition that the forced draft fan does not trip but cannot output power occurs or not in the running process according to changes in the total air volume of a power generator set, the outlet pressure of the forced draft fan, and the motor current parameters of the forced draft fan; and when the abnormal working condition is detected, triggering the abnormity RB operation on a forced draft fan system in time, and taking a series of protecting actions. Compared with the prior art, the RB control method provided by the invention has the advantages that the abnormal working condition that the forced draft fan cannot output power can be judged in time although the forced draft fan does not trip, the loads of the power generator set can be rapidly reduced, and the safe and stable running of the power generator set can be maintained.