Abstract: The structure and operation features of shaft seal system of 600MW turbine made by siemens were introduced. Aiming at the problems occurred in operation, the relevant solving methods were put forward. The safety and economical of the shaft seal system were analyzed and the result can be used as reference for commission and operation of similar units.

Key words: shaft gland seal, average temperature of high-voltage rotor, steam temperature for steam seal, self-sealing, prohibit to supply steam for seal