Abstract: Abstract:Aiming at the problems of larger steam leakage and lower reliability of the steam seal of a 300MW domestic unit, according to analysis on the structure characteristics of current steam seal and the existed problems before the seal reformation, the turbine seal reformation scheme and the reformation measures were put forward. After the seal had been reformed, the steam leakage of the high and middle pressure cylinder, the steam leakage in the end of the turbine and the interstage steam leakage were reduced; the physical work capacity of the steam and the relative inner efficiency were increased. The thermal economic efficiency of the unit was improved.

Key words: Key words:steam turbine, Brandon steam seal, honeycomb steam seal, reformation, heat consumption rate