Soft measuring method for main steam flow of unit system utility boiler

The invention discloses a soft measuring method for main steam flow of a unit system utility boiler. The soft measuring method comprises the following steps of: detecting a pressure and a temperature of steam at a boiler outlet, and the pressure and the temperature of the steam at a steam turbine inlet in real time, and utilizing a formula to calculate flow mass qms (kg/s) of the steam, wherein K denotes an area flow coefficient (m ); rho denotes density of the steam in the pipeline (Kg/m ); pB denotes the pressure of the steam of the boiler outlet (Pa); pT denotes the pressure of the steam of the steam turbine inlet (Pa); H denotes a height difference (m) between a steam pressure measuring point at the boiler outlet and a steam pressure measuring point at the steam turbine inlet; and g denotes an acceleration of gravity (m/s ). The soft measuring method disclosed by the invention has a simple calculation process, has high static accuracy, has a rapid dynamic response speed, achieves a reliable calculation result, does not increase throttling loss, and is applicable to measuring of the main steam flow of various unit system utility boilers.