Abstract: Control of the throttle pressure in a drum boiler-turbine system is accomplished by controlling the rate of fuel feed with a cascade control system. When fuel feed cannot be directly measured, but is computed from boiler output, the controllers in the system are decoupled to prevent their interaction. The primary control responds to throttle pressure deviation to produce a heat release demand signal which is compared to the calculated heat release. A signal produced by summing components of the heat release calculation, namely steam flow and rate of change of drum pressure, is used to cancel out any contribution to the input to the primary controller by changes in throttle pressure resulting from disturbances in the fuel feed, which disturbances will be corrected by the secondary or fuel feed controller.