At present

the actual flow capacity of mainstream turbines universally deviates from the design value.Analysis on this and the flow characteristic tests were conducted.The results showed that

the flow capacity of 300 MW steam turbine with improved flow sections was about 2%-8% larger than the design value

so the cylinder efficiency deviated from the design value.The efficiency of high pressure cylinder under rated load condition was about 13.2%-1.86% lower than that under three valves full opening condition.The parameters of each extraction section deviated from the design value.The steam distribution was unreasonable.The flow capacity of the 600 MW steam turbine was obviously higher than that of the 300 MW steam turbine.That of the imported turbine agreed well with the design value

for the deviation was only about 0%-3%.