Abstract: In a system and method for automatically starting, synchronizing and operating a steam turbine, turbine control including valve position limiting and means for generating a reference control signal representative of desired turbine operation, the reference control signal being limited corresponding to the valve position limit. The reference signal is limited by calculated valve position limits, such that the reference signal is not permitted to rise above such limits. Desired system changes result in reference signal changes which are more quickly reflected in valve position changes, thereby enabling improved system response.

Abstract: In a system and method for automatically starting, synchronizing and operating a steam turbine, control means for valve position limiting wherein such limit can be changed non-linearly. Means are provided whereby the system operator has the ability to manually select a minimum incremental change of the valve position limit as a keyboard-entered constant. If the operator enables a continuing change in the limit it is introduced arithmetically, permitting large swings in a reasonably short period of time.

Abstract: A steam turbine is provided with an automatic digital computer controller and a backup analog controller which are interfaced with an electrohydraulic position control for the turbine throttles and governor valves. Valve position signals are generated by transducers and applied to the valve position control along with position setpoint signals from the computer or the backup controller for the purpose of generating valve control signals which drive the valves until the position setpoints are satisfied. The position signals are also applied to the computer where they are compared to the computer valve position setpoints. The automatic controller and the analog backup controller each have a speed/load control which generates the valve position setpoints in accordance with a speed or load reference, and the backup control tracks the computer setpoints during automatic control.

Abstract: In a system and method for automatically starting, synchronizing and operating a steam turbine, proportional plus integral feedbck control utilizing digital computer systems is adapted to correspond to physical valve operation by applying integration limits. Useful for both speed and load control modes of operation, the demand signal is compared with prior values thereof, and the differential is both multiplied by a proportional gain factor, and integrated in the computer utilizing numerical integration techniques. The integrated total is kept within a desired range by applying upper and lower limits, and the limited integral is combined with the proportional factor, further limited, as desired, and appropriately scaled for use as a process variable.