Taking ultra-supercritical 1 000 MW units in Huaneng Yuhuan Power Plant and Guodian Beijing Power Plant as examples

on the basis of analysing problems occurred in the run back(RB) test

such as large fluctuation of negative pressure in the furnace

and of pressure in the primary air manifold

as well as large fluctuation of steam temperature resulting from serious misadjustment of the water/coal ratio

etc.

an optimization of control strategy for the furnace pressure

the pressure in primary air manifold

and the steam temperature during run back of the units have been carried out.Practical application shows that the effectiveness of RB control for units after optimization has been remarkably enhanced.