Abstract: A change-over type of loading device assembly includes a low-voltage small-capacity type of capacity-variable type loading element in which the capacity is incrementally variable by a capacity change-over element, a transformer connected to said capacity-variable type loading element, a connecting terminal mounted on said capacity-variable type loading element or said transformer, and a plurality of fixed loading elements having the respective connecting terminals and connected in parallel with each other together with said capacity-variable type loading element. These fixed loading elements include a circuit formed by connectively combining a plurality of resistors with each other and comprising element bodies, each receiving the output power from a power generator, and change-over devices for changing one of said resistors in said circuit to another depending upon operation so as to allow the withstand voltage of said circuit to correspond to the output power from said power generator.

Abstract: The problem for distributing load equally between multiple generators (34) in multi-channel generating systems is resolved using a voltage regulator (60) including a reactive load division loop (84) and real load division loop (86). The voltage regulator (60) controls generator excitation responsive to sensed voltage. The reactive load division loop and real load division loop modify the voltage regulator output to divide loading equally between each generator.

Abstract: A method of selectively isolating faulty channels in a parallel electric power system having at least two controllable AC power sources includes the steps of producing a DC content signal representative of the magnitude of DC voltage in an AC output of one of the power sources and producing a differential current signal representative of differential DC current flowing in connected phases of the power sources. The DC content and differential current signals are combined to produce an error signal which is used to control the operation of the first power source, thereby reducing the magnitude of DC voltage in its output. When the error signal exceeds a predetermined threshold level, a trip signal can be produced and used to selectively isolate a failed channel in the power system. Following isolation of the channels, the differential current signal is disabled such that the error signal is only representative of the DC content signal for split channel operation.

Abstract: A system for effecting parallel operation of a pair of AC power sources includes a monitoring circuit for monitoring the difference voltage occurring between output voltages on corresponding phases of the power sources. A capacitor is connected to a charging circuit and to an output of the monitoring circuit. When the difference voltage occurring between the output voltages on corresponding phases of the power sources exceeds a predetermined threshold level, the capacitor is shorted. Paralleling of the power sources is inhibited when the capacitor voltage is below a second predetermined threshold level.

Abstract: Power sources of a parallel AC electrical power system are synchronized by producing a voltage difference signal representative of the difference in output voltages of the power sources and demodulating that signal to produce a frequency control signal and a voltage magnitude control signal. The output frequency and voltage magnitude of at least one of the power sources is varied in response to the frequency control signal and voltage magnitude control signals, respectively, to minimize the difference in output voltages between the power sources.

Abstract: An induction generator system is disclosed for utilization with an oil producing well having casing gas available at the wellhead and an existing electrical power system. An electric motor is coupled to the existing electrical power system and is utilized as a generator to drive a submersible pump or other electrical load. A gas engine which is powered by the casing gas is mechanically coupled to the electric motor by means of a drive belt and is utilized to drive the electric motor at a speed greater than the synchronous speed of the motor. While the electric motor is driven at a speed greater than its synchronous speed it will generate electrical energy which can be utilized to carry the electrical load. A novel control system is utilized to control the operation of the engine/motor generator system in response to variations in motor speeds, engine operating parameters and load/voltage conditions.

Abstract: A demodulator circuit utilizes a switching demodulation technique to detect the real and reactive components of load current unbalance in a parallel source alternating current power system. A signal representing load current unbalance is selectively switched to a pair of output terminals in response to a series of pulse wave control signals which bear a phase relationship with the Thevenin equivalent voltage of one of the power sources such that the signal appearing at one of the output terminals represents the real load current component while the signal at the other output terminal represents the reactive load current component. The signals at these terminals are fed back to control the frequency and voltage magnitude of one of the power system sources to eliminate load current unbalance.

Abstract: A load control for a system comprised of a plurality of energy converters wherein a System Control Signal proportional to system load is developed and utilized to simultaneously adjust the rate of energy conversion of each of the converters in parallel in accordance with changes in system load. The rate of energy conversion for each converter, while operating under stead-state conditions for a predetermined period of time, is readjusted until its actual incremental cost of production is equal to a desired incremental cost.

Abstract: A method for modifying an area control error signal for controlling the generation in each area of a multiple-area interconnected electric power system using net-interchange tie-line bias control where the area control error is calculated in accordance with the equationACE=.DELTA.P.sub.t1 -10B.times..DELTA.fwhere .DELTA.P.sub.t1 is the deviation of the measured net interchange from its scheduled value, .DELTA.f is the deviation of a system frequency from its set value, and B is the frequency bias of the area. The modification involves the integration of .DELTA.P.sub.t1 to produce a signal representing a measured value of the inadvertent interchange II'.sub.t1, and integration of .DELTA.f to produce a signal representing the time deviation TD'. The time deviation is multiplied by the value 10Bf.sub.o /3600 times 1/T where B is the area frequency bias and 1/T is the control weighting factor. The product of the multiplication is subtracted from the signal II'.sub.

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: A load, such as a logic network of the TTL type, is connected in parallel across a plurality of direct-current sources designed to maintain a substantially constant operating voltage. Each source includes a control unit which compares the load voltage with a reference level in order to stabilize the output voltage of an associated current generator at that level. If the generator current drops below a certain minimum value, however, a threshold sensor in the control unit raises the reference level up to an amount equaling about twice the maximum divergence possible between the reference levels of different control units, thereby ensuring that all sources contribute simultaneously to the load current.

Abstract: A voltage regulation circuit includes an active integrator circuit which generates an output signal representing the time integral of the error between the voltage across a load and a reference voltage. The integrator circuit output is connected to a series of voltage comparators (each having hysteresis) each of which controls one of a series of separate switch elements each controlling a proportion of the total current flow from a source to the load.

Abstract: This invention introduces the concept that on an interconnected electric power system, the area-caused components of memory parameters system time deviation and the total inadvertent interchange of each constitutent control area are separable and measurable. Methods and means are disclosed for separating each of the components and determining its magnitude, utilizing known or measurable parameters, thereby providing new long-desired area memory parameters which are precise measures of the control performance of each area. The portion of system time deviation and the portion, designated primary inadvertent, of total area inadvertent interchange caused by an area's own regulating deficiencies, and the portion, designated secondary inadvertent, of total area inadvertent interchange caused by regulating deficiencies of each remote area, are identified.

Abstract: Control systems for controlling load division among plural power sources coupled in parallel and providing power to a common load using feedback techniques. Control systems for various types of plural power sources are disclosed, including DC generators, hydraulic variable displacement pumps and AC generators driven by a constant speed drive. The outputs of the individual power sources are responsive and proportional to individual input control signals. The magnitude of a power component common to all the power sources or frequency, if the power sources are AC generators driven by constant speed drives, is compared to a reference to provide an error signal. Individual sensors sense the magnitude of a variable power component from each power source and provide a signal proportional thereto. Individual signals representing the variable power component are combined with the error signal to provide the individual control signals for each power source.

Abstract: An isolated electrical power generation system is described with multiple isochronous, load-sharing engine-generator units. The system includes load sensing means for generating a signal representing the individual power output of each engine-generator unit, means for generating a signal representing the total power output of all the engine-generator units in the system, and load-sharing means responsive to deviations between each individual power output signal and the total power output signal for controlling the fuel inputs to the respective engines in the various units. A load simulating means responds to the occurrence of a preselected condition, such as an excessive temperature, in an individual unit for adding a simulated power output signal to the individual power output signal for that particular unit.

Abstract: A demand limiting system is provided for a large electrical energy customer with at least one modulating load. A master control unit continually compares the actual power usage to the desired rate of power usage. When the desired power consumption rate is exceeded by a first amount, the master provides a hold signal to an associated slave control unit, which prevents further loading of the modulating load. When the desired rate of power consumption is exceeded by a second amount, the master provides a reduce signal to the slave unit, which begins to reduce the load. While the hold signal is calling for a reduced load, only a fraction of the time is utilized to reduce the load, and the remainder of the time the modulating load is in the hold condition, allowing the system to stabilize and prevent hunting. The reduce signal also regulates load shedding equipment, to disconnect non-critical loads.

Abstract: A device for the voltage regulation of a solar-type generator by the additive or subtractive connection of generator units to a common bus bar. A logic circuit controls the number of unregulated generator units being connected to the bus bar at any one time depending on the load. A single generator is permanently coupled to the bus bar which generator is regulated to provide improved overall regulation. This single, permanently connected generator is regulated by a series regulator having high feedback loop gain for substantially reducing the output impedance of the single regulated generator in comparison to the unregulated generators. An embodiment incorporating d.c.-a.c. choppers for supplying an a.c. load is also disclosed. In this embodiment, the choppers are directly controlled to effect coupling between a generator and the common bus bar.