Abstract: The control circuit employs a controller having an I-member and a servo-motor whose rate of adjustment is limited and which is associated with a follow-up. The follow-up enables the operative movement of the servo-motor to act on a comparator in the control circuit between the output of the controller and the input of the servo-motor. The output of the comparator is also connected to attenuating means which are operative in the entry path of the I-member. The attenuating means includes a functions pick-off and a multiplier element. The functions pick-off delivers an output signal which is lower for a high absolute value of its input signal than for a low absolute value. This output signal acts via the multiplier element on the entry path of the I-member.

Abstract: A system and method for operating a turbine power plant, wherein a demand signal based upon load or total turbine steam flow required for a predetermined level of operation controls the value of individual signals representative of valve position for respective steam inlet valves in the single and sequential mode of operation, is disclosed. Each individual valve position signal, which is representative of a selected portion of the total demand signal, is dynamically calculated to reflect the effect of the pressure drop across the nozzles, and to correct for the number of inlet nozzles, associated with each valve. The total demand signal is modified in accordance with actual throttle pressure over a period of time that is dependent on the amount of throttle pressure change.

Abstract: A load control for a system comprised of a plurality of energy converters wherein the energy output of all converters is adjusted in parallel to maintain the total rate of energy output from the system equal to demand and wherein during steady-state conditions the rate of energy conversion for that converter having the lowest incremental cost is increased and simultaneously the rate of energy conversion for that converter having the highest incremental cost is decreased a like amount.

Abstract: An auxiliary power unit for an aircraft drives an electrical generator and an air compressor. The auxiliary power unit is primarily intended for operation with the aircraft on the ground when other aircraft power systems are shut down. The auxiliary power unit may, however, be used in an emergency to supplement the main aircraft generating system, with the aircraft airborne. When the auxiliary power unit generator is used in conjunction with the aircraft generating system, inlet air to the compressor is controlled to vary the compressor load on the power unit to minimize power unit speed changes and electrical frequency transients.

Abstract: Apparatus and method for the partial load operation of a combined gas turbine and steam turbine plant, including a shaft being connected to the gas turbine and drivable at a given nominal speed of rotation, a first generator being connected to the shaft and electrically connectible to an electric network, a compressor being connected to the shaft and connected upstream of the gas turbine in gas flow direction, a heat exchanger having an output and a variable heat supply and being connected upstream of the gas turbine in gas flow direction, a steam generator for the steam turbine being connected downstream of the gas turbine in gas flow direction for receiving exhaust gases therefrom, a second generator being connected to the steam turbine and electrically connectible to the electric network for supplying given nominal power thereto along with the first generator, means for giving to the electric network and taking away from the network at least part of the nominal power if the shaft rotates at less than the n

Abstract: In a power plant which includes a steam turbine with main control valves for admitting steam into the steam turbine and a steam bypass with bypass control valves for diverting steam around the steam turbine directly into a condenser, it is necessary to coordinate the operation of the respective valves so that the steam turbine can be started, brought up to speed, synchronized with a generator and then loaded as smoothly and efficiently as possible. The present invention provides for such operation and, in addition, allows for the transfer of power plant operation from the so-called turbine following mode to the boiler following mode through the use of the sliding pressure concept. The invention described is particularly applicable to combined cycle power plants.

Abstract: A speed regulator or governor for an engine. The governor utilizes the approximate digital equivalent of a lead and a lag feedback network in combination with a stored, digital, nonlinear look-up table, or other nonlinear means, to control engine speed. The governor controls the engine at different fixed engine speeds in response to demand, or at continuously variable engine speeds in response to demand.

Abstract: An optimized high load blocking limit is independently computer calculated for each gas turbine-generator unit as a dynamic function of combustor shell pressure and exhaust temperature every second. A low load blocking limit can be calculated as a function of the high blocking limit. The high and low dynamic limits then define a band of megawatts instantaneously available to the system. At the dispatch computer, load-frequency control is executed and the calculated load demands are dispatched to the various gas turbine-generator units which respond without exceeding the respective high and low load blocking limits. A turbine control unit load reference is modified by the dispatched load change and each unit load control operates its turbine fuel control valves to satisfy the load demand.

Abstract: A speed governor for a hydroelectric unit includes an error sensing means, an integrator and a gate opening control means connected to the output of the integrator for controlling the degree of opening of the turbine gate apparatus. The governor further comprises a limiter connected between the output of the error sensing means and the input of the integrator for limiting the maximum value of the integrator input signal to a limit value equal to the minimum integrator input signal value which insures the maximum permissible rate of change of the degree of opening of the gate apparatus.

Abstract: When the rate of increase of the load on a gas turbine with time is higher than a reference value, the amount of fuel supplied to the turbine is temporarily increased whereas, when the rate of decrease of the load with time is higher than a certain predetermined value, the amount of fuel supplied to the turbine is temporarily decreased. However, for a certain predetermined time interval after this decreasing of the fuel amount has ended, an increase in the amount of fuel supplied to the turbine is suppressed to a minimum even if the load on the gas turbine increases.

Abstract: The power and speed control device for a turbo-generator set of the invention has a generator, a turbine, and a governing valve with a positioning control input, for regulating steam fed to the turbine. The device includes a turbine speed controller, a turbine power controller, a maximum selection circuit, a minimum selection circuit, a summing stage, and a device for supplying a constant reference value to the input of the summing stage. The controllers are connected to the maximum selection circuit and the speed controller is additionally connected to the summing stage. The summing stage is connected to the minimum selection circuit, the maximum selection circuit is connected to the minimum selection circuit, and the minimum selection circuit is fed to the positioning control input of the governing valve.

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 and control and turbine system failure detection means. More specifically, open, shorted, grounded and reversed thermocouples are detected and alarmed. Problems of any one combustor in a multiple combustor arrangement are similarly detected and alarmed. Additionally, automatic correction of previously computed temperature related control inputs is provided in response to detected variations from a predetermined temperature reasonability criterion. Novel placement and orientation of system thermocouples facilitates achieving improved monitoring, detection and control.

Abstract: A dedicated supervisory control system for a steam turbine-generator comprising a hierarchy of microcomputer subsystems interactive with a conventional analog electrohydraulic control system to provide control and monitoring capabilities during all operating phases of the turbine-generator. The separate microcomputer subsystems are programmed for coordinated interaction and communication through shared, dual-port read/write memory units and each microcomputer subsystem is programmed and configured to handle a separate group of control responsibilities in a distributed control system.

Abstract: A control system is provided for turbines in the utility part of an industrial plant using cogeneration so that control is maintained over the relative quantities of steam supplied to a common steam header from both the back pressure and the extraction turbines where the header supplies process steam at a predetermined pressure. The steam flow from a stage of the extraction turbine is controlled to maintain the header pressure at its desired value. The steam flow thus controlled is measured and a control means is provided to control the steam flow from a back pressure turbine supplying the same header so as to maintain a predetermined relationship between the two steam flows while maintaining electrical generation from the generators driven by the turbine at a maximum consistent with maintenance of an adequate control range for the header pressure control.

Abstract: A system and method of operating a turbine power plant utilizing a digital computer to transfer automatically between a single valve mode and sequential valve mode of operation and vice versa without disturbing the load or steam flow demand to the turbine, is disclosed. Selecting the other mode of valve operation when operating automatically in one valve mode results in the generation of physical representations corresponding to the desired flow through each of the valve means in such other mode at the operating load or flow level. The flow in the one mode and the desired flow in the other mode is used to generate a representation based on flow change for each valve means. A number of increments of valve flow change for each valve means is determined in accordance with the largest valve flow change and a predetermined limit. The size of each incremental change is determined in accordance with the respective valve flow change.

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: In a system and method for automatically starting, synchronizing and operating a steam turbine, turbine control including valve position limiting and means for generating a reference control signal representative of desired turbine operation, the reference control signal being limited corresponding to the valve position limit. The reference signal is limited by calculated valve position limits, such that the reference signal is not permitted to rise above such limits. Desired system changes result in reference signal changes which are more quickly reflected in valve position changes, thereby enabling improved system response.

Abstract: A throttle valve test system for a large steam turbine functions in a turbine control system to provide throttle and governor valve test operations. The control system operates with a valve management capability to provide for pre-test governor valve mode transfer when desired, and it automatically generates feedforward valve position demand signals during and after valve tests to satisfy test and load control requirements and to provide smooth transition from valve test status to normal single or sequential governor valve operation. A digital computer is included in the control system to provide control and test functions in the generation of the valve position demand signals.

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: The specification discloses a solar power plant which utilizes a sun-tracking parabolic collector and a plurality of energy storage and conversion devices, all of which are operated under the control of a novel energy management system. Allocation of energy to a particular storage component or to useful output is dependent upon the state of the system as well as the nature of the demand. Outputted energy may also be recaptured and reallocated to minimize losses. Efficiency at the component level is enhanced by the utilization of novel heat exchangers which effectuate complete conversion of the operating liquid to superheated gas.

Abstract: The present stress in the turbine rotor is estimated at each control period, from the steam temperature and pressure at the turbine inlet. In addition, the future turbine inlet steam temperature or pressure is preestimated once every n.sub.T control cycles, for a given speed or load changing rate, making use of data concerning the changing rate of the turbine steam inlet temperature or pressure in relation with the change of the speed or load, which has been obtained by a learning of the past turbine operating condition. This future steam temperature or pressure at the turbine inlet is used as a factor for preestimating the future stress expected to be caused in the turbine rotor. The preestimation of the rotor stress is performed for a plurality of assumed speed or load changing rates. The turbine is controlled at the maximum speed increase-rate or load changing rate which would not cause the future stress preestimated over a given preestimation time to exceed a limit stress.

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 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: Apparatus and method for setting, controlling, and maintaining a given turbine inlet temperature in a gas-driven turbine and AC generator driven thereby having the generator output connected to a fixed frequency AC infinite bus. The method comprises providing electric signals proportional to generator rotational speed, turbine inlet temperature, and generator output power respectively. These three signals are processed and combined with two independent reference electric signals, representing preset desired values of rotational speed and turbine inlet temperature, to provide an output which, when applied to an electrically actuated fuel flow control means, will maintain a constant given turbine inlet temperature.

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: In a system and method for automatically starting, synchronizing and operating a steam turbine, control means for valve position limiting wherein such limit can be changed non-linearly. Means are provided whereby the system operator has the ability to manually select a minimum incremental change of the valve position limit as a keyboard-entered constant. If the operator enables a continuing change in the limit it is introduced arithmetically, permitting large swings in a reasonably short period of time.

Abstract: An automatic electrical load matching device for applying loads to wind den generators. The device switches five different loads to the output of a wind driven generator. Each load corresponds to a range of speeds of the wind driven generator's rotor.

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 steam generators and a digital/analog control system. A gas turbine megawatt load control system is included in the control and it includes a feedforward load control which generates a fuel reference equal to the sum of a megawatt load demand and an idle speed fuel demand. The megawatt load control also includes a feedback load trimmer which provides minor corrective action on the operation of the feedforward load control. Gas turbine and combined cycle plant operation results in the generation of megawatts equal to an input demand value.

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: Present speed and present steam temperature are utilized in accordance with a mathematical model to evaluate present steam to turbine heat transfer and turbine heat propagation quantities, and present turbine rotor and casing surface and volume average temperatures. The model is corrected for inaccuracy based on comparison of calculated rotor to casing differential expansion with measured values, and is exercised once more with anticipated speed and steam temperature quantities to develop anticipated rotor to casing differential expansion and anticipated rotor stress. These quantities are compared with various predetermined limits to determine whether the present and anticipated speed and acceleration are within allowable limits.

Abstract: A system for intelligently governing the selection of one of a boiler follow or turbine follow mode of control of a steam turbine power plant is disclosed. Boiler and turbine master controllers are concurrently operative in one of the boiler follow and turbine follow modes for controlling the firing rate of the plant boiler or positioning the steam admission valves of the steam turbine, respectively. Each of the boiler and turbine master controllers are operative to respectively generate a first and second plurality of signals which are representative of plant control status. A selecting means is disposed as an integral part of the plant controls for switching between the turbine follow and boiler follow control modes.

Abstract: An electrohydraulic control system and method are disclosed for operating valves controlling the admission of steam to a steam turbine. The system includes a mode transfer unit for effecting a transfer between a full arc mode of valve operation to a partial arc mode of operation such that the temperature of the steam turbine varies in a controlled manner, thus permitting control of turbine stresses. Apparatus is described for generating mode flow signals, combining the signals using time ratio switching such that during a mode transfer the signals vary linearly with an admission reference factor characteristic of each mode, and generating valve lift signals from a combined flow signal using multi-slope, piecewise linear approximations to the flow-lift characteristics of the full arc mode of valve operation. The system permits mode transfers wherein total steam flow is held substantially constant and first stage turbine temperature is caused to vary linearly with admission reference factor.

Abstract: An overspeed protection controller (OPC) which is incorporated as part of a turbine speed/load control system for the purposes of controlling the monitored speed of a steam turbine at a first predetermined speed valve subsequent to an OPC activation is disclosed. The governor and interceptor valves of the steam turbine are positioned controlled by a set of electrohydraulically operated valve position servo systems. The OPC provides for rapid hydraulic closure of each valve when activated by either a detection of an interruption of generated electrical power flow to a power system load when the generated electrical power is greater than a predetermined value or the detection of the monitored turbine speed being greater than a second predetermined speed value. The rapid closure of the valves results in an interruption of steam flow to the high and lower pressure turbine sections of the turbine system which causes steam energy to be trapped in the reheater which is disposed between the turbine sections.

Abstract: A control device for turbines with speed and load control, in which the load control includes an integrator with or without an output value limiter. The speed control and the load control are functionally independent of each other over the entire working range. The speed control likewise includes an integrator, and the outputs of the two controls are conveyed to a MIN-member as input signals while the smaller input becomes the output signal of the MIN-member and takes over the positioning of the turbine inlet valve.

Abstract: A combined cycle electric power generating system which drives two electric power generators at a constant speed. It employs a gas turbine to drive one of the generators and a steam turbine to drive the other. There is a combustor that supplies the gas to drive the gas turbine and there is an air compressor that feeds input air to mix with fuel into the combustor. The compressor is driven by the gas turbine. The exhaust from the gas turbine delivers heat to make steam for the steam turbine. And, there is means for throttling the inlet air to the compressor so that the whole system may be run at greatly reduced load without creating inefficient operation.

Abstract: A control system for generating a control signal at a first station, transmitting the control signal to a second station, and processing the control signal at the second station to provide a controlled output. At least some of the processing equipment at the second station draws electrical power, and power for such purposes is generated by a generator located at the second station.

Abstract: A regulation system for a steam turbine installation comprising a steam generator and a multi-stage turbine installation incorporating a high-pressure stage. The regulation system comprises a regulation valve arranged between the steam generator and the high-pressure stage of the turbine installation and a by-pass valve connected in parallel with said high-pressure stage, as well as control devices with associated control circuits for said valves. The control device for the by-pass valve is influenced by the signal from the control circuit of the regulation valve such that when the opening of the regulation valve exceeds a predetermined magnitude the control device for the by-pass valve opens such by-pass valve to a predetermined magnitude. Further, the control circuit of the by-pass valve is connected in parallel with a differentiation element which influences the degree of opening of the by-pass valve as a function of variations in the signal received from the control circuit of the regulation valve.

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 system for protecting a turbine-generator power plant governed by signals representative of turbine mechanical power and generator electrical power to reduce at times the turbine mechanical power, with an electronic filter included therein for the purposes of filtering a periodic time varying component of the electrical power signal having a response time within adequate protective limits, is disclosed. More specifically, the electronic filter generates a train of fixed time durations wherein during each fixed time duration the maximum and minimum amplitudes of the electrical power signal are selected. A signal is sampled at the end of each fixed time duration and held constant for each next fixed time duration, said signal being representative of the average of the maximum and minimum amplitudes selected during each fixed time duration.

Abstract: The majority of a number of relays is held in a quiescent state, without power, in a local maintenance controller preparatory to assumption of control of a gas turbine power plant. Control transfer may be manually requested or may occur automatically in response to failure of the plant's primary control system. Regardless of the cause of transfer, a time delay relay is utilized to allow the quiescent relays sufficient latching time. The time delay period is chosen to reflect the maximum period of time for which a lack of trip availability can be safely tolerated.The relay sequencing arrangement is adapted so that when the quiescent relays are energized, alarm circuitry for predetermined plant parameters is automatically reset for on-line transfers, thereby allowing more rapid and efficient transfer and minimizing the need for operator intervention. Alternative means for manually resetting the alarm circuitry is also provided.

Abstract: A black start generating system for a steam plant comprises a gas turbine-generator and a control system which operates the turbine in a modified dead load mode to accept successive load steps in accordance with a black plant startup sequence. In the dead load mode, certain limits are placed on control operations to protect the turbine while permitting load stepping during plant startup.

Abstract: An electrohydraulic system for rapidly reducing the steam flow through the high pressure and lower pressure stages of a turbine power plant in response to a partial loss of electrical load, is disclosed. In response to the detection of a partial loss of load, the system provides for controlling a portion of the governor valves and all of the interceptor valves to close rapidly and independently of the turbine control system; also to operate the turbine control system to cause the remaining governor valves to operate to a predetermined partially closed condition independent of the normal governor valve reference demand signal by applying a signal for changing the open limit position of the governor valves; and to eliminate the affect of the impulse pressure loop from the turbine control system. The upper valve position limit signal and the slower rate of change reference demand signal is matched to the applied signal.

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: A system for indicating optimum positioning of steam inlet valves to minimize steam throttling losses during operation of a turbine power plant in the sequential valve mode is disclosed.

Abstract: A power plant arrangement having a gas turbine, a heat recovery steam generator, a steam turbine and means for controlling steam flow from the heat recovery steam generator to the steam turbine so that steam conditions are maintained generally constant and variations in power plant loading are carried by the steam turbine while operating the gas turbine at a generally constant fuel flow.

Abstract: An electric power generator incorporating an automobile alternator operable in a high voltage mode suitable for providing power for hand power tools and in a low voltage mode suitable for maintaining the charge of a battery which provides a field current for the alternator. A switching circuit, manually or automatically actuable to place the generator in the high voltage mode of operation, interposes a voltage regulator in the field current circuit and connects the output of the alternator to the battery to charge the battery when the generator is operated in the low voltage mode and interposes a variable resistor in the field current circuit and disconnects the battery from the output of the alternator to permit adjustment of the output voltage of the alternator when the generator is operated in the high voltage mode.

Abstract: Apparatus for generating minimally delayed closing instructions for turbine valves of turbo-generator sets in the event of power system short circuits wherein major faults resulting in a drop in the system voltage are detected and act upon the valve means controlling the fluid flow to the turbine in such manner that a rapid closure of the valve means prevents the turbo-generator from falling out of step in the case of a sustained fault condition. A provisional valve-closing signal is produced upon a predetermined drop in the system voltage but this is cancelled in the event that the ensuing acceleration of the turbo-generator set does not increase to a predetermined level within two revolutions of the set.

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: As an improved way of effecting fast valving of turbines of power system steam-electric generating units for the purpose of improving the stability of power transmission over transmission circuits to which their generators make connection .Iadd., .Iaddend.when stability is threatened by line faults and certain other stability endangering events, and in which intercept valves are rapidly closed on a momentary basis, the procedure of intercept valve closure is supplemented by simultaneously initiating turbine and steam supply source control programs, which (a) .[.being.]. .Iadd.bring .Iaddend.into effect a sustained reduction in turbine driving power via employment of measures which may include full closing of some or all control valves and/or employment of preprogrammed control valve repositioning, with provision to automatically divert high pressure steam to the condenser or to atmosphere as a way to prevent discharge of steam through high pressure safety valves.