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.

Abstract: A steam turbine control system includes an operator panel and a digital computer which operates the turbine valves through an electrohydraulic control. Turbine speed and load signals and valve position signals are coupled to the computer for use by the computer control loops in developing valve control signals. Two separate displays are provided on the operator panel, one for the speed or load reference and the other for the speed or load demand. Dedicated pushbuttons on the panel enable certain other parameters such as acceleration or load rate or valve position limit to be displayed in the reference display, while other pushbuttons can be used to address and display in the reference or demand display general control system parameters. A mechanism is provided for entering changes into the computer for the various parameters and for displaying such changes in one of the displays.