Abstract: A turbine control system for changing over a throttle governing operation of a steam turbine to a nozzle governing operation thereof and vice versa by controlling control valves on the basis of a main control flow-rate request signal comprises function generators grouped according to the two governing operations and operating to produce function outputs in response to the opening degrees of the control valves. The function outputs are biased according to the two governing operaton and applied to respective high-value gates, the output signals of which are compared with the main control flow-rate request signal to control the opening degrees of the control valves in such a manner that the flow rate of steam introduced through the control valves into the steam turbine are maintained constant during the speed governing operation changing period.

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: 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: Unnecessary fast valving action for load loss protection in a steam turbine generator system induced by partial transducer failure is minimized by the disclosedmethods and apparatus. Upon the occurrence of a mismatch between reheat pressure and electrical output, the interceptor valve is closed momentarily to interrupt the flow of steam to the low-pressure turbine and prevent overspeed. The valve cannot be closed again for a predetermined interval. If the mismatch is not corrected by the one fast valving action, a transducer has failed and further closing of the interceptor valve, except for a full load loss, is precluded until corrective action is taken. The faulty transducer is singled-out by comparing one of the transducer signals with the impulse pressure which is also an indication of the actual operating level of the turbine.

Abstract: The regulator having a P-member and an I-member uses a timing means to delay the desired value signal prior to subtraction of the delayed signal from the received actual value signal. The resultant signal is then delivered to the I-member. A further P-member is also used to receive the desired value signal and to deliver the signal for addition to the superimposed signals from the first-named P-member and I-member in order to produce a load-control signal.

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. The digital/analog system includes a steam throttle pressure limiting control, which maintains a minimum steam throttle pressure as a function of steam flow to limit the maximum steam velocity through the steam generators, and reduce the probability of water carryover into the steam turbine. In response to a reduction in the number of steam generators in service, the pressure flow relationship is transferred from one characterization to another, and during such transfer, the analog system operates the steam turbine control valves to limit the rate of steam pressure decay as a function of steam flow.

Abstract: Apparatus for the control of steam-heating power plants to optimize the use of energy in producing the required steam and electrical power comprising means for sensing steam and electricity demands, means for comparing these sensed demands with the electricity and steam output of turbine means in the plant, and means for adjusting operating set points of the turbines and steam generator for coordinated control of power plant energy consumption and production.

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 digital computer control system for operating a steam turbine in an electric power plant is disclosed. Under automatic control, the digital computer calculates a steam flow demand signal for positioning the steam inlet valves. A speed feedback loop is used to modify the steam flow demand signal as required to maintain the desired speed. The speed loop selects a first or second of three independently generated speed signals depending on the difference between the three speed signals. The first speed signal is a digital signal; and the second is an analog signal, which is converted to a digital signal. The digital signal consists of a fine and a coarse speed signal which is selected in accordance with turbine speed to constitute the first generated speed signal.

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: 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 digital computer system for automatically controlling a turbine power plant without operator intervention is disclosed. The system controls the turbine from rolling off turning gear, through heat soak, wide range speed control, and the megawatt loading of the generator in accordance with the on-line condition of the turbine and/or generator. The rate of change of magawatt loading as well as the rate of speed under wide range speed control is automatically controlled toward an operator entered target. The I.P. rotor thermal characteristics are determined both in axial and radial directions. The on-line generator capability is determined in load control.

Abstract: The 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: Inplant sensors in the boiler and turbine units sense present values of a number of physical parameters designated process variables, and of certain control variables. Set points are developed, and deviations therefrom of the control and process variables are calculated. Utilizing a mathematical model, state variable deviations are estimated and translated into corresponding physical parameter estimates, which are used to evaluate model inaccuracy. State variable and model error estimates are translated into desired control deviations, which in turn are combined with fed forward values of the control variable set points. The combined control terms actuate controllers in the boiler and turbine units.

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.

Abstract: There is disclosed a heat-engine/battery-electric hybrid power system for use in a low-pollution, low-fuel consumption vehicle. The engine shaft is coupled by a fixed mechanical ratio to the shaft of a dynamotor, the field current of the dynamotor being controlled by the accelerator pedal for drawing power from a battery to aid the engine in the turning of the driveshaft or for drawing power from the driveshaft to recharge the battery. A feedback loop is employed for continuously adjusting the throttle so that the manifold vacuum remains constant. In this manner, the ratio of the engine exhaust to the driveshaft speed remains substantially constant. The engine exhaust is directed to a thermal reactor, secondary air for which is derived from an air pump driven by the engine shaft. The ratio of the exhaust gas to the secondary air is thus substantially constant independent of the shaft speed so that the thermal reactor is maximally effective at all vehicle speeds.

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: As an improved way of effecting fast valving of turbines of power system steam-electric installations of types that incorporate by-pass systems for by-passing steam from a point ahead of the high pressure turbine either directly to the condenser or to the cold reheat line, and in the latter case also from the hot reheat line to the condenser, and where the purpose of employment of fast valving is to improve the stability of power transmission over transmission circuits to which the generators of the installations in question make connection, when stability is threatened by line faults and certain other stability endangering events, the approach of rapidly closing intercept valves at fastest available closing speed in response to a fast valving signal, is supplemented by bringing into effect preprogrammed processes of control valve repositioning, plus intercept valve reopening, so effected as to cause turbine driving power subsequent to generator rotor first forward swing to hold below a preset value that is l

Abstract: A turbine control system for changing two speed governing operations of a steam turbine from a throttle governing operation to a nozzle governing operation and vise versa by controlling steam control valves comprises function generators grouped according to the two speed governing operations and operated by a main control flow-rate request signal to produce function outputs which are applied to respective low-value gate circuits, means for comparing the sum of the outputs of the gate circuits and the main control flowrate request signal, and means for varying the main control flowrate request signal with the aid of the difference between the signals thus compared in such a manner that while one of the outputs of the gate circuits decreases, the other output increases to supplement the decrease, whereby the steam control valves are gradually operated with the output of the turbine being kept unchanged during the operating mode changing operation.

Abstract: A combined cycle power plant includes gas and steam turbines and steam generators and a digital/analog control system. A megawatt load control system varies a fuel control signal to govern a detected power output according to a reference value. The fuel control signal determines the flow rate of fuel to the combustor of a gas turbine-generator that is adapted to use gas and liquid fuels. A flow divider comprises a plurality of gear pumps connected to rotate with a common shaft, and distributes liquid fuel equally to a plurality of nozzles of the combustor, the total liquid fuel flow to the nozzles being related to the shaft speed. The shaft speed is detected and a signal representative of the total liquid fuel flow is generated in response to the detected speed.

Abstract: A method of switching a hydro-electric unit from the group power control into the individual power control duty is disclosed wherein control system, preferentially featuring an electrohydraulic controller, of the hydro-electric unit being switched into the individual control duty is not fed with the output voltage available from the common power pre-setter of all the hydro-electric units under group control, but with the output voltage available from the individual power pre-setter of the hydro-electric unit being switched into the individual power control duty.

Abstract: A steam turbine operates with a control system having a programmed digital computer for automatically controlling steam flow to satisfy turbine speed or load demand during turbine startup, synchronization and load operation. Steam flow is controlled throughout the entire startup sequence by means of speed control signals determined by the computer as a function of monitored turbine operating conditions. While under load operation the turbine is under digital computer load control, and operational parameters are monitored by the digital computer.

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.

Abstract: An intermediate intercept valve controlling method and system for use in a heat power plant wherein the occurrence of a fault in a transmission system is detected by an abrupt decrease in generator output, and the intercept valve is closed to a certain opening depending upon the magnitude of an output variation and is then opened when a rotor angle between the internal voltage and terminal voltage of the generator reaches the first peak value.

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: There is provided a vehicle engine-driven alternator wherein an internal combustion engine is coarsely adjusted to a preset speed by an engine governor, the turning driving force of the engine is transmitted to an alternator through a magnetic slip coupling, and the excitation current to the magnetic slip coupling is controlled by an excitation control circuit which compares the number of revolutions of the alternator with a preset value to generate an output depending on the result of the comparison, thereby providing a source of alternating current having an extremely accurate preset frequency.

Abstract: A combined cycle power plant includes gas and steam turbines, gas turbine afterburners, steam generators, and a digital/analog control system. A megawatt load control system varies a fuel control signal to govern a detected power output according to a reference value, the fuel control signal determining the flow rate of fuel to a gas turbine. An afterburner is connected to heat the exhaust gas from the gas turbine. Both the gas turbine and the afterburner are adapted to use gas and liquid fuels. During gas turbine fuel transfer, the gas and liquid fuel flows are controlled in response to the fuel control signal to compensate power output disturbances that typically result from various nonlinearities of fuel system elements. Afterburner fuel transfer is initiated upon completion of gas turbine transfer.

Abstract: Instead of supplying all electrical current for residences or similar buildings from a single central station by way of distribution power lines, each building is also provided with its own engine-driven electrical generator the output terminals of which are connected to the power lines. The heat from the engine in each building is used in satisfying the thermal load for that building, for example to heat the building and the domestic hot water, and/or to supply heat for heat-input forms of air conditioners or refrigerators. Thermostatic control is used to turn the engine on and off as needed to perform its heating function. The electrical current generated while the engine is running is used to supply part or all of the electrical load in the building, and any excess is supplied to the distribution power lines. A two-way watt-hour meter registers the net electrical power flow in or out of the building to enable securing of credit for the current delivered to the power lines from each building.

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 combined cycle electric power plant includes gas and steam turbines and steam generators and a digital/analog control system. The control system includes an automatic control and a backup control which are interfaced to operate the gas turbine throttle valve for speed and load control purposes and to provide for manual/auto transfers. The backup control includes a startup control which functions on the basis of a feedforward fuel schedule ramp function. Between ignition speed and 78% synchronous speed, the ramp function is a linear function of fuel demand versus speed with a predetermined slope. From 78% of synchronous speed to idle speed, the ramp function is a linear function with a lesser slope.

Abstract: An electric power plant including a steam generator and a steam turbine is operated by a control system including a turbine control, a boiler control and a plant unit master; each of the aforementioned controls includes integrating or adaptive controllers responsive to error signals to effect a desired control and ramp generators to provide an output against which a control process may be tracked. The integrating controllers include an integrating circuit for integrating an input error signal and a proportional circuit responsive to the error signal for providing an output signal to be summed with the output of the integrating circuit. The constant of the proportional circuit and the time constant of the integrating circuit are changed as a function of an index. In a control for an electric power plant, the index is the load reference provided by the plant unit master. A ramp generator is suggested that is capable of generating linear ramps at a fixed rate toward a known value, e.g.

Abstract: A digital computer control system is provided for operating a steam turbine in an electric power plant. The computer develops steam valve position signals to control turbine speed and load. Various turbine temperature, pressure and other process parameter signals are coupled to the computer which stores the parameter values along with other parameters such as control loop setpoints in its memory. Another computer at the plant level or at the system dispatch level is coupled to the turbine computer through a data link which includes data link programs in each computer and data transmitter and receiver circuitry connected to the two computers. The higher level computer is the controlling computer on the data link. Control words are used to identify data transmission modes and validity checks are made on transmitted words. Turbine computer core data is accessible and transmittable to either higher level computer.

Abstract: An electrohydraulic emergency trip system which automatically shuts off the steam supply to a turbine power plant upon the detection of specific operational contingencies is disclosed. The hydraulic portion of the system includes two pair of combined electrical and hydraulically operated pilot trip valves that are so arranged that the opening of any one valve of each pair decreases the hydraulic trip pressure to close rapidly the steam inlet valves to the turbine; that an open or closed failure of a single trip valve does not prevent a valid trip or cause an unwarranted trip; and finally that an open failure of one pair of the valves does not result in an unwarranted trip. Each pair of valves is electrically operated from an independent voltage source such that the electrical failure of one source does not cause or prevent an unwarranted turbine trip.