One-machine-to-multiple-network pressurized water reactor nuclear power unit large-scale steam extraction heat supply system

The invention discloses a one-machine-to-multiple-network pressurized water reactor nuclear power unit large-scale steam extraction heat supply system which comprises a steam turbine high-pressure cylinder, two heat supply steam extraction pipelines are connected to an exhaust pipeline, each heat supply steam extraction pipeline is divided into two branch pipes, and each branch pipe corresponds to a column of heat supply network heaters; the first heat supply network is connected with one heat supply steam extraction pipeline through two rows of heat supply network heaters, and the two rows of heat supply network heaters comprise a heat supply network heater A, a drain cooler A, a heat supply network heater B and a drain cooler B; the second heat supply network is connected with the other heat supply steam extraction pipeline through two rows of heat supply network heaters, and the two rows of heat supply network heaters comprise a heat supply network heater C, a drain cooler C, a heat supply network heater D