The invention discloses a
power station unit multi-steam-source shaft seal steam /
gas supply system and a control method thereof. The
power station unit multi-steam-source shaft seal steam /
gas supply system comprises a high-pressure cylinder, a medium-pressure cylinder, a low-pressure cylinder, a shaft seal cooler, a hydrophobic air
heat exchanger, a desuperheater (A), a desuperheater (B) and a rotor connected with a cylinder body accessory; the steam inlet side of the high-pressure cylinder and the steam inlet side of the medium-pressure cylinder share a first
branch shaft seal to supply steam, and residual steam enters a shaft seal steam return main
pipe through a steam return pipeline manual valve after a shaft seal cavity is sealed; the steam exhaust sides of the high-pressure cylinder and the medium-pressure cylinder share a second
branch shaft seal to supply steam, the desuperheater is arranged on a second
branch steam supply pipeline, and a measuring point for measuring the temperature of the steam is arranged behind the desuperheater and in front of a shaft seal body; and all shaft seal return steam of the high-pressure cylinder, the medium-pressure cylinder and the low-pressure cylinder is gathered and then enters the shaft seal cooler. The
system has the advantages of multi-source steam supply, parameter matching, flexible
control mode, reliable protection logic and automatic tracking under accident conditions.