Steam turbine system

A steam turbine system comprising:

• a steam turbine including a plurality of rotor blades that are configured to rotate around a rotating shaft with steam within a casing and are arranged at intervals in a central axis direction of the rotating shaft so as to form a plurality of stages;
• a first mixed steam supply pipe that is configured to supply the steam, which is supplied from a steam supply source allowing supply of the steam with fluctuating pressure, to an upstream stage within the casing;
• a second mixed steam supply pipe that is provided to branch from the first mixed steam supply pipe and is configured to supply the steam to a downstream stage located on a downstream side with respect to the upstream stage within the casing;
• an adjusting unit that is configured to adjust a flow rate of the steam supplied from the first mixed steam supply pipe to the upstream stage and a flow rate of the steam supplied from the second mixed steam supply pipe to the downstream stage;
• a detection unit that is configured to detect a differential pressure between a pressure of the steam supplied from the steam supply source and a pressure in the upstream stage;
• and
• a control unit that is configured to control the adjusting unit on the basis of the differential pressure detected by the detection unit, wherein
• the control unit is configured to control the adjusting unit so as to increase the flow rate of the steam supplied from the second mixed steam supply pipe to the downstream stage in a case where the differential pressure is smaller than a predetermined reference value, and
• the reference value is determined on the basis of correlation data that is preset on the basis of a relationship between a flow rate of the steam supplied from the steam supply source and a differential pressure required to supply the steam of the flow rate into the casing.