Abstract: A thermal collector of solar energy includes an elemental semiconductor material to absorb a substantial portion of the energy of solar radiation that is incident upon the material. At longer wavelengths, such material reradiates absorbed energy at a substantially reduced rate, whereby the efficiency of energy collection at high temperatures is improved. In a solar electric power plant collected heat is transferred from such collectors to a motive fluid, which drives a turbine-generator. The high operating temperature of the energy-absorbing material permits efficient conversion of the collected energy to electrical energy, while a required number of solar collectors is correspondingly reduced by the improved collection efficiency.

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: An analog control system and a digital system are provided with an integrated interface for the input/output signals used in monitoring and controlling an electric power plant. Plant analog and digital inputs are processed through circuitry which provides input signals compatible for use in both the analog and the digital systems. Analog and digital outputs are similarly processed through circuitry which provides compatible signals. Output signals are directly applied from the analog control to the digital system or vice versa without need for buffering.

Abstract: A once-through boiler is provided with integral separators with which drain valves are associated. Boiler inlet and outlet flows are balanced throughout startup first by drain valve control in response to separator level and then by drain valve control in response to throttle pressure.

Abstract: A boiler control regulates the input fuel and air to satisfy load demand. Simultaneously, the air flow is adjusted by an air flow control to correct for changes in fuel heating value by means of a circuit which operates in response to outlet steam flow and input mass fuel flow to determine the difference in presumed heat input and actual heat output and, by inference from the heat imbalance or error, a change in fuel heating value. The heat error is used to adjust the air flow demand to the air flow control. In another embodiment, boiler heat pickup is derived to remove from the heat imbalance any heat input changes other than fuel heating value changes.

Abstract: A boiler control regulates the input fuel and air to satisfy load demand. Simultaneously, fuel flow is adjusted by fuel flow control to correct for changes in fuel heating value. A computer circuit which generates a heat balance ratio of outlet steam flow and input mass fuel flow as a representation of imbalance between presumed heat input and actual heat output and by inference from the imbalance or change in fuel heating value. The heat balance ratio is multiplied against an actual fuel feedback signal and the ratio corrected signal is applied to the fuel flow control.

Abstract: Apparatus for detecting and recording status changes of two-state devices in a power network substation, a pipeline substation, or the like. At a substation a remote terminal unit records status changes in its digital memory. When a sequence of status changes occurs, each change is recorded, together with its time of occurrence as measured from the time of occurrence of the first change, thereby reducing the size of memory for recording sequence data. Upon request, data related to a sequence of changes is transmitted to a master station in chronological order of the changes, to simplify processing of such data at the master station. Provision is made to permit the master station to convert elapsed time to real time, and to reduce the time required of the master station to retrieve sequence data from a remote terminal.

Abstract: An electric power plant including a steam generator and a steam turbine is operated by a control system including two redundant digital computers. Switching circuitry is provided for coupling one of the computers through interface equipment to the steam generator and the turbine and a generator according to programmed computer control. A data link is established between the computers to transfer manual/automatic status and other needed data from the control computer to the standby computer. A system is provided for detecting when certain hardware and software malfunctions have occurred and for responsively transferring control to the standby computer. The standby computer is tracked to the control computer so that control computer transfer can be made reliably without disturbing the electric power generation process. The turbine control includes a speed control loop which is implemented with computer operations.

Abstract: An electric power plant including a steam generator and a steam turbine is operated by a control system including two redundant digital computers. Switching circuitry is provided for coupling one of the computers through interface equipment to the steam generator and the turbine and a generator according to programmed computer control. A data link is established between the computers to transfer manual/automatic status and other needed data from the control computer to the standby computer. A system is provided for detecting when certain hardware and software malfunctions have occurred and for responsively transferring control to the standby computer. The standby computer is tracked to the control computer so that control computer transfer can be made reliably without disturbing the electric power generation process.

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 gas turbine power plant is provided with an industrial gas turbine which drives a generator coupled to a power system through a breaker. The turbine-generator plant is operated by a hybrid control system having digital function capability during sequenced startup, synchronizing, load buildup and steady state load, and shutdown operations. The control system also contains monitoring and protective subsystems which function through all stages of operation, with redundancy and permissive features which maximize turbine availability.

Abstract: A hybrid digital computer gas turbine power plant control system which may operate in a multiple-control loop arrangement is provided with selected process variable monitoring means. Control system inputs representative of current values of such variables are continuously available to provide positive highly responsive control over a broad range of gas turbine operating conditions. Predictable process sensor errors are effectively eliminated by means of programmed computer operations to thereby insure highly accurate control variable derivation essential to maintaining gas turbine operation at or near design limits.

Abstract: In a combined cycle plant, a process flow demand signal is applied to multiple sequentially operated boiler feedwater valves through a single manual/automatic (M/A) station. Each valve is positioned in accordance with its position/flow characterization so that the total feedwater flow to the boiler satisfies the flow demand. To provide for bumpless manual to automatic transfer, valve position signals are characterized with the inverse of the respective valve characterizations in the flow region not covered by a lower order valve. The characterized outputs are set to zero in flow regions covered by a lower order valve. A high selection of the characterized outputs is performed and the selected signal corresponds to the process flow demand value which will enable a manual to automatic transfer without causing an upset in steam generator process flow or electric power generation.

Abstract: An electric power plant including a steam generator and a steam turbine is operated by a control system including two redundant digital computers. Switching circuitry is provided for coupling one of the computers through interface equipment to the steam generator and the turbine and a generator according to programmed computer control. A data link is established between the computers to transfer manual/automatic status and other needed data from the control computer to the standby computer. A system is provided for detecting when certain hardware and software malfunctions have occurred and for responsively transferring control to the standby computer. The standby computer is tracked to the control computer so that control computer transfer can be made reliably without disturbing the electric power generation process. The turbine control includes a load control loop which is implemented with computer operations.

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 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. Further, override signals are generated to prevent the temperature of the superheated steam from falling below a predetermined minimum level and for preventing the temperature and pressure of the superheated steam from exceeding maximum levels.

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. Automatic synchronization is achieved with a hybrid subsystem which includes the programmed computer and external phase detection circuitry. An automatic synchronization program for the computer is divided into rough speed and voltage matching, fine speed matching and breaker closure subprograms.

Abstract: An electric power plant including a steam generator and a steam turbine is operated by a control system including two redundant digital computers. Switching circuitry is provided for coupling one of the computers through interface equipment to the steam generator and the turbine and a generator according to programmed computer control. A data link is established between the computers to transfer manual/automatic status and other needed data from the control computer to the standby computer. A system is provided for detecting when certain hardware and software malfunctions have occurred and for responsively transferring control to the standby computer. The standby computer is tracked to the control computer so that control computer transfer can be made reliably without disturbing the electric power generation process. Tracking is produced by a system which includes the data link as well as tracking controls in the noncontrolling computer.

Abstract: A steam turbine is provided with inlet throttle and governor valves which are positioned by an electrohydraulic control. A digital computer includes a speed control and a load control which respond to turbine speed and load signals and an electrical load signal to generate position control setpoints for the valves. A load reference is generated from an input load demand, and the reference is modified by a speed correction and selectively acted upon by a megawatt control and an impulse pressure control in the generation of the valve position setpoints. On the insertion of the megawatt control or the impulse pressure control into service, or on its removal from service, the computer instantly resets control parameters as required to provide for bumpless control loop switching.

Abstract: A combined cycle electric power generating plant includes gas and steam turbines and a heat recovery steam generator 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 gas turbine includes a plurality of variably set guide vanes whose position may be set to determine the inlet flow to the gas turbine. Guide vane control apparatus is provided to limit the inlet guide vane position as a function of gas turbine compressor inlet temperature in accordance with a desired gas turbine exhaust flow, and to match the gas turbine exhaust flow to the steam requirements of the steam generator as in turn determined by the load placed upon its steam turbine. In addition, an afterburner is provided to supplementally heat the exhaust gas turbine gases before they are directed to the steam generator.