The invention belongs to the technical field of thermoelectricity, and relates to an extraction condensing
heat supply system additionally provided with a non-reheat medium-pressure
steam turbine. A part of steam is separated from a steam exhaust port of a high-pressure cylinder of a main
steam turbine to enter the added non-reheat medium-pressure
steam turbine, and the rest of steam enters a reheater of a boiler and a No.II high-pressure heater; the steam entering the medium-pressure steam
turbine does not need to be reheated, an independent generator II is driven, four-stage extraction steam of the medium-pressure steam
turbine serves as a heat source for a No.III high-pressure heater, a No.V low-pressure heater, a No.VI low-pressure heater and a
deaerator to replace a part of regenerative extraction steam of the main steam
turbine, and the extraction steam of the medium-pressure steam turbine is discharged into a heater for heating network to heat heating network water. An effect of additionally installing the medium-pressure steam turbine in the extraction condensing
heat supply system disclosed by the invention is to reduce heat exchange
exergy loss by reducing heat exchange
temperature difference of a part of regenerative heaters and the
deaerator; work capability of
heat supply steam flow is increased, and therefore heat loss of a high-capacity heat supply unit is caused by a high extraction steam parameter is reduced; and the extraction condensing heat supply
system disclosed by the invention is suitable for heat supply and
energy conservation transformation on 300 MW (megawatt), 600 MW and above steam turbine units.