Based on the matrix analysis method used for thermodynamic system of steam turbine unit

the thermal economic efficiency of one ultra-supercritical 1 000 MW steam turbine unit has been analysed

the influence of desuperheating water for boiler's superheater and reheater upon thermal economic efficiency of unit being calculated respectively.Calculation show that the influence of water-spraying desuperheat upon the thermal economic efficiency is comparatively large

under operating condition of THA

the flow rate of desuperheating water is 80 t/h

the desuperheating water for reheater is taken from the intermediate joint head of feed-water pump

the coal consumption rate for electricity generation will increase 1.6 g/kWh

the feed-water taken from outlet of high-pressure heater no.3 will also increase 1.2 g/kWh.