Abstract: A combined cycle electric power plant includes in interconnected relationship a steam turbine, two gas turbines, three electric generators, two heat recovery steam generators, a hybrid computer control system, a plant protection system and various items of auxiliary equipment. A computerized simulator is interfaced with the control system at the factory site to test the controls and the control system is then modularly disassembled in various structures and shipped to the field site for reassembly without need for extensive field testing. The control system includes a digital control computer, a digital monitor computer and modular analog controls for the turbines. Various levels of automated control can be employed including coordinated plant control which involves supervisory operation of the analog controls by the control computer. In analog control, complete plant operation is produced by operation of the analog controls without the control computer.

Abstract: A combined cycle electric power plant includes gas and steam turbines and a steam generator for recovering the heat in the exhaust gases exited from the gas turbine and for using the recovered heat to produce and supply steam to the steam turbine. The steam generator includes a superheater tube through which a fluid, e.g. water, is directed to be additionally heated into superheated steam by the exhaust gas turbine gases. An afterburner further heats the exhaust gas turbine gases passed to the superheater tube. The temperature of the gas turbine exhaust gases is sensed for varying the fuel flow to the afterburner by a fuel valve, whereby the temperatures of the gas turbine exhaust gases and therefore of the superheated steam, are controlled. The afterburner fuel flow is controlled through a feedforward setpoint signal derived as a predetermined function of sensed gas turbine exhaust temperature.

Abstract: Steam flow and pressure conditions needed in a turbine to satisfy the speed and load demand of an electric power generating system are controlled by a programmed digital computer system during start-up, synchronization and load operation. Manual backup control is provided for the computer control. Throttle valve tests are provided under digital control and transfers are made to manual backup control if predetermined task errors occur.

Abstract: Steam flow and pressure conditions needed in a turbine to satisfy the speed and load demand of an electric power generating system are controlled by a programmed digital computer system during start-up, synchronization and operation. Manual backup control is provided for the computer control. An operator interface is provided with the computer through a panel and various communication devices.

Abstract: A combined cycle electric power plant includes gas and steam turbines and a steam generator for recovering the heat in the exhaust gases exited from the gas turbine and for using the recovered heat to produce and supply steam to the steam turbine. Afterburners further heat the exhaust gases from each gas turbine prior to their passage to respective heat recovery sections of the steam generator. The power plant control system provides coordinated plant control or coordinated control of selected turbines and afterburners in both startup and load operations, with load distribution optimized according to the turbines under coordinated control. Transfer between coordinated control and alternate modes of plant control may be done by operator selection or automatically upon sensed conditions.

Abstract: A control system for a steam turbine includes an operator's panel and a programmed digital computer which generates valve position signals for the turbine throttle and governor valves. Mode select signals are generated at the panel and the computer includes a mode selector which provides for structuring the control system to implement external synchronizer, load runback, automatic turbine startup, operator automatic, manual and other mode selections.

Abstract: A combined cycle electric power plant includes two gas turbines, a steam turbine, and a digital control system with an operator analog or manual backup. Each of the gas turbines has an exhaust heat recovery steam generator connected to a common header from which the steam is supplied by one or both of the steam generators for operating the steam turbine. The control system is of the sliding pressure type and maintains a predetermined steam pressure as a function of steam flow according to a predetermined characterization depending on the number of steam generators in service to limit the maximum steam velocity through the steam generators, and reduce the probability of water carryover into the steam turbine. Such control is always maintained by the bypass valve. The turbine control valve responds to the speed/load demand only, except when the bypass valve is closed and the rate of steam generation is insufficient to maintain a predetermined pressure flow relationship.

Abstract: A combined cycle electric power plant includes gas and steam turbines and a steam generator for recovering the heat in the exhaust gases exited from the gas turbine and for using the recovered heat to produce and supply steam to the steam turbine. The steam generator includes a superheater tube through which a fluid, e.g. water, is directed to be additionally heated into superheated steam by the exhaust gas turbine gases. An afterburner further heats the exhaust gas turbine gases passed to the superheater tube. The temperature of the gas turbine exhaust gases is sensed for varying the fuel flow to the afterburner by a fuel valve, whereby the temperatures of the gas turbine exhaust gases and therefore of the superheated steam, are controlled. A plant load demand error signal is utilized for correcting a coordinated gas turbine load reference and for trimming a feedforward afterburner control signal derived from the sensed gas turbine exhaust temperatures.

Abstract: A combined cycle electric power plant includes gas and steam turbines and a steam generator for recovering the heat in the exhaust gases exited from the gas turbine and for using the recovered heat to produce and supply steam to the steam turbine. The steam generator includes a superheater tube through which a fluid, e.g. water, is directed to be additionally heated into superheated steam by the exhaust gas turbine gases. An afterburner further heats the exhaust gas turbine gases passed to the superheater tube. The temperature of the gas turbine exhaust gases is sensed for varying the fuel flow to the afterburner by a fuel valve, whereby the temperatures of the gas turbine exhaust gases and therefore of the superheated steam, are controlled. Loading and unloading of the steam turbine is accomplished automatically in coordinated plant control as a function of steam throttle pressure.

Abstract: A combined cycle electric power plant includes gas and steam turbines and steam generators and a digital/analog control system. In the control system, an automatic digital computer control generates position setpoints for the gas turbine fuel valves and the steam turbine inlet valves to control turbine speed and load. A synchronizer system includes an automatic synchronizer subsystem and a manual synchronizer subsystem. The automatic synchronizer subsystem includes a sequencer which is largely embodied in the digital computer and it further includes a synchronizer which is external to the automatic control. The automatic sequencer connects the synchronizer to synchronize the three generators in a sequence which depends on the startup and loading operation of the turbines, the synchronization operation of the synchronizer and the operation of the breakers. The manual synchronizer subsystem responds to operator inputs to generate a speed reference for the synchronization of each turbine.

Abstract: A combined cycle electric power plant includes two gas turbines, a steam turbine, and a digital control system with an analog or manual backup. Each of the gas turbines has an exhaust heat recovery steam generator connected to a common header from which the steam is supplied by one or both of the steam generators for operating the steam turbine. Both the digital and the analog systems provide a digital input to an interface for controlling the steam turbine valves. The analog system is controlled to operate a respective valve by an input to its interface which determines valve position in accordance with its duration. The digital system is controlled to operate a respective valve by an input to the interface in accordance with the repetitive duration of the signal. The analog system input and digital system input is applied to an interface for each valve.

Abstract: A combined cycle electric power plant includes gas and steam turbines and steam generators and a digital/analog control system. An automatic digital portion of the control system includes a speed control which generates a speed error from the actual turbine speed and a turbine speed reference, and a proportional plus integral controller acts on the speed error to generate a fuel reference for the gas turbine fuel valve position controls after ignition and during wide range speed control. A speed reference generator includes a stored representation of speed as a function of time with zero time made equal to the point in time at which the flame goes on. The speed versus time characterization is made up of three linear parts having different slopes.

Abstract: The throttle and governor valves of a steam turbine are operated by a digital computer control system to provide speed and load control for the turbine. The computer includes a speed and load control which periodically generates control outputs and a separate logic control which responds to panel and contact inputs to generate logicals which structure the speed and load control. An analog scan periodically enters feedback parameters into the computer for use by the controls. An input contacts scan enters feedback logicals into the computer on demand, or under certain conditions periodically. A monitor operates with an auxiliary synchronizer to control the execution of the scans and the controls. The speed and load controls are bid for execution once each second to generate the control outputs which are applied to an external electrohydraulic control for the valves.