The invention provides a shaft-seal steam supply
system for a secondary reheat unit. The shaft-seal steam supply
system comprises a shaft-seal main
pipe, an auxiliary steam supply
station, an overflowcontrol
station, a temperature reduction control
station and an
electric heating control station; the shaft-seal main
pipe is provided with a plurality of first
branch pipes which are respectively connected with an ultrahigh pressure cylinder rear shaft seal, an ultrahigh pressure cylinder front shaft seal, a
high pressure cylinder front shaft seal, a
high pressure cylinder rear shaft seal, a middle pressure cylinder front shaft seal and a middle pressure cylinder rear shaft seal, and the pipeline between the shaft-seal main
pipe and the ultrahigh pressure cylinder front shaft seal is provided with the
electric heating control station; the shaft-seal main pipe is also provided with a plurality of second
branch pipes which are respectively connected with the auxiliary steam supply station,the overflow control station and the temperature reduction control station; and the
tail end of the shaft-seal main pipe is also connected with a steam supply port of the low pressure cylinder shaftseal by virtue of the temperature reduction control station. The invention also provides a control method of the shaft-seal steam supply
system for the secondary reheat unit. By adopting the shaft-seal steam supply system, the steam supply temperature of each shaft-end shaft seal can be accurately controlled, the power and size of an electric heater can be reduced, and the operation economical performance of the unit can be improved.