Abstract: A steam turbine system, including a plurality of blade stages arranged axially along a first shaft, an impulse stage configured upstream of the plurality of blade stages, the impulse stage having an impulse wheel and a casing, the casing including a plurality of inlet sections with each of the plurality of inlet sections having a corresponding nozzle group and operatively connected to a corresponding control valve controlling a first steam flow through the corresponding nozzle group, a first inlet configured to provide the first steam flow through the impulse stage and the plurality of blade stages, and, a second inlet configured to provide a second steam flow to the plurality of blade stages and bypassing the impulse stage.