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 gas turbine power plant is provided with an industrial gas turbine which drives a rotating brushless exciter generator coupled to a power system through a breaker. One or more of the turbine-generator plants are operated by a hybrid digital computer control system during sequenced startup, synchronizing, load, and shutdown operations. The program system for the computer and external analog circuitry operate in a multiple gas turbine control loop arrangement. Logic macro instructions are employed in programming the computer for logic operations of the control system.

Abstract: An arrangement is provided for resetting the fuel inlet pressure to the throttle valve in response to sensed changes in nozzle fuel pressure to compensate for variations in the fuel viscosity resulting from changes in fuel temperature. The fuel nozzle pressure is automatically maintained at a fixed value during the ignition sequence to assure reliable ignition without overfueling throughout the range of site ambient temperature variation.

Abstract: A fuel control schedules fuel to a gas turbine to produce a scheduled speed profile during startup. The scheduled speed profile is continuously compared to actual turbine speed during startup, and the difference is compared to an alarm setpoint and a trip setpoint. Normally, temperature and surge limit controls prevent the turbine from accelerating too fast; and, if the turbine is accelerating too slowly, an alarm output is generated when the actual/desired speed difference reaches the alarm setpoint and the turbine is tripped when the actual/desired speed difference reaches the trip setpoint.

Abstract: A signal representative of liquid fuel flow or gaseous fuel pressure is compared to a limit value throughout the startup and load operation of a combustion turbine. Under predetermined fuel supply conditions the turbine is either alarmed or tripped. The fuel limit value is a function of combustor shell pressure and altitude.

Abstract: A digital computer system provides automatic control for a steam turbine and two gas turbines in a combined cycle electric power plant during startup and load modes of operation. The gas turbine automatic control system provides speed, load and blade path temperature control functions in developing an output fuel control signal for application to each gas turbine fuel valve control. An analog control for each gas turbine selectively provides startup and temperature and load control functions as a backup for the automatic gas turbine control, and further provides gas turbine overspeed, surge and other limit controls continuously. An operator panel functions with the analog and digital controls to provide an operator interface with the plant, and an interface circuit ties the digital and analog controls together for bumpless transfer between manual and automatic modes of operation.

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 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 speed and load. A synchronizer system includes a sequencer which is largely embodied in the digital computer as an element of the automatic control and it further includes a synchronizer which is external to the automatic control. The 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. Turbine speed changes are initiated by the speed/load control under synchronizer control.

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 functions with temperature and other detectors to provide temperature limit control for the gas turbines through the fuel valve position controls provided therefor. A blade path temperature reference is generated as a function of combustor shell pressure during the startup and load modes of operation, and during the load mode of operation the blade path temperature reference is further generated with dependence on the actual turbine exhaust temperature. In particular, the turbine blade path temperature is allowed to rise under loading operation until it reaches a limit value defined by a predetermined combustor shell pressure characteristic curve.