OPERATION CONTROL SYSTEM FOR STEAM TURBINE

PURPOSE:To minimize the excess accompanying steam quantity under a partial load in particular and reduce the accompanying steam loss by guiding a moisture extracting pipe to a steam separator newly provided outside turbine stages, and controlling the accompanying steam quantity in response to the magnitude of the turbine load. CONSTITUTION:The final stage of the low-pressure turbine 3 of a steam turbine plant is constituted of multiple stator blades with slits, the moisture in the steam stuck on stator blade faces is sucked into hollow sections in the blades, and the moisture in the steam is separated and removed. The moisture is discharged by moisture discharge pipes 14a, 14b, a merged moisture discharge pipe 15 is connected to a steam separator 16, and the accompanying steam phase 17 and the moisture drain phase 18 are completely separated. The accompanying steam phase 17 is guided to a condenser 13 by an accompanying steam quantity control valve 26 through an accompanying steam discharge pipe 62 via an accompanying steam flow meter 28 and condensed. The opening quantity of the accompanying steam quantity control valve 26 is controlled by the magnitude of the turbine load, i.e., the magnitude of the output signal 59 of a generator output detector 58.