Abstract: The faults of lower efficiency of HP casing and larger steam leakage were often occurred in domestic 300MW unit manufactured using introduced technique, and the economical efficiency of unit operation had been influenced. A reformation scheme of flow path of 300MW unit was introduced, in which the combinations of Brandon steam gland and honeycomb gland was adopted. The performance data of the unit before and after reformation were compared each other, and the conclusion obtained is that using newstyle gland rationally can improve the unit performance.

Key words: Key words:efficiency of HP casing, data of flow path, heat rate, steam leakage of shaft gland, 300MW steam turbine