Superheated steam is used to increase cycle efficiency. This superheated steam is produced by the superheater which is oversized to allow boiler turndown and changes in fuel. The desuperheater is used to maintian a consistent superheated steam temp.
DSH Pump Starts and stops the desuperheater pump.
Round Gauge Shows if DSH pump is on
Desuperheater Regulates the temperature of the boiler steam used in the turbine