The additionally supplying steam at overload in large scale steam turbines was presented.Taking a 600MW unit as the example

the effect of additionally supplying steam structure on the unit performance was quantitatively analyzed.The results show that:after the supplying steam valve was applied

the unit's power efficiency increased by 38.949 MW

about 6.40%growth;but the unit heat consumption rate increased by 59.2kJ/(kW·h)

the economic efficiency reduced by 0.78%;the high pressure cylinder efficiency dropped by 1.96%.Therefore

in summer or other days with high electricity load

using the additionally supplying steam technology is safe and feasible

though it will cause a little decrease in unit economy.