Abstract: Abstract:The parameters reflecting the condenser operation conditions were introduced. The influencing factors, which cause the condenser vacuum degree to lower, were analyzed, and the diagnosis basis of the factors was explained. The diagnosis method of vacuum degree lowering in normal unit operation was illustrated by practical example, and the concepts of extreme vacuum degree and optimal vacuum degree were put forward. The results in this paper can be used as reference for economical operation of steam turbine unit.

Key words: Keywords:condenser, vacuum degree, exhaust temperature, temperature rising of circulating water, terminal difference, optimal vacuum degree, extreme vacuum degree