Abstract: There is provided a high voltage power supply utilizing a high leakage reactance transformer connected to a voltage doubler which has a capability of reversing its output voltage. The power supply is of a type which may be used at several different input frequencies. There is provided an inexpensive low voltage switch connected to the secondary winding of the transformer and to ground. The low voltage switch is used to switch from one number of turns to another number of turns on the secondary winding depending on the frequency of the input signal.

Abstract: A method and apparatus for disconnecting a load from a power source when the voltage from the power source falls below a first predetermined level and for reconnecting the load to the power source when the voltage rises above a second predetermined level. The voltage of the power source is constantly sensed and when the voltage falls below a first predetermined level a switch means, which is connected between the power source and the load, is opened, thereby disconnecting the load from the power source. An auxiliary coil is placed in series with the load so that, when a load drawing an initially large current is connected to the power source, the increased current through the auxiliary coil produces a magnetic force to hold the switch means closed even though a voltage below the first predetermined level is sensed. In this manner, false disconnection of the load from the power source is prevented.

Abstract: The utilization of EHV networks and underground cables in today's modern power system has created a reactive power control problem. In particular, system generators are being forced to absorb large quantities of reactive power to maintain system voltage.

Abstract: In a monitor for determining the real electrical power being delivered by a 3-phase source to a load, each phase voltage and a voltage which is proportional to and in phase with the corresponding line current are coupled to separate balanced detectors Each detector provides a DC voltage which is proportional to the real power being delivered by its corresponding phase The DC voltages from the balanced detectors are connected in series and the resulting sum voltage is coupled to a plurality of voltage comparators Each voltage comparator provides a signal when the sum voltage exceeds a predetermined magnitude and each of the voltage comparators is set to respond to a different sum voltage magnitude Since the sum voltage is proportional to the real power being delivered by the source, within the range of voltage magnitudes set, the output signals of the voltage comparators provide a measure of the power being delivered by the 3-phase source A binary output means, such as a relay, is controlled by each comparator

Abstract: Reactive-power installations at suitable points become necessary in most modern high-voltage networks, to prevent excessive voltage drops at load busbars. In the paper, the minimisation of the total required reactive-power installation is formulated as a nonlinear-programming problem. Based on certain specific features of this problem, a new solution technique, which results in a considerable reduction of computational effort, as compared with general optimisation techniques, is developed. An additional feature of this technique is that it can be used in conjunction with any standard a.c. load-flow program. The technique is applied to a typical network to bring out the advantages of this approach. An extension of this technique for cases where the voltage restrictions have to be satisfied for two or more loading conditions is also presented.

Abstract: A circuit for lighting a plurality of lamps requiring a temporary starting voltage and an operating voltage of a different value than the starting voltage. The starting voltage source is switched completely out of the line during operation. An impedance device is provided in series with the lamps which is preferably a capacitor. Since the starting voltage is turned on for only a short period of time, the starting voltage source may be of a small power output requirement compared with the main power source.

Abstract: Established means for measuring or detecting reactive power, power or power factor have an inherent time delay, mainly because of the need for output filtering. This letter describes an arrangement employing sampling techniques, which, since no filtering is necessary, offers substantial advantages for control and monitoring applications.

Abstract: A TTL (transistor-transistor-logic) compatible voltage controllable crystal digital clock having a relatively wide linear frequency control range with relatively small control voltage range. A quartz crystal in series with a voltage variable reactance is coupled in a regenerative loop of an oscillator circuit. A control voltage varies the capacitance of the voltage variable reactance resulting in a phase shift around the regenerative loop and changing the frequency of oscillation of the circuit.

Abstract: Installation of reactive-power sources in the form of static capacitor banks is usually resorted to in distribution systems to reduce the energy loss and to achieve any required voltage correction. In this paper, the minimisation of the annual cost of energy loss and the annual cost of capacitor installation is first formulated as a time-dependent optimisation problem. The specific characteristics of distribution systems and the cyclic nature of the load variations permit the reformulation of the problem as a static quadratic programming problem.

Abstract: A means of assessing the relative merits of single-ended and push-pull switching converter or inverter stages is presented. The dependency of those merits upon the range of input voltage and output current is set forth. For a single-ended high-frequency converter stage, the relationships among output power, switch current and voltage ratings, input voltage range, and reset voltage reveal the criticality of transformer design. Transformer stored energy considerations for optimum output power dictate absolute control of leakage reactance as well as the shape of the magnetization curve.

Abstract: The demands of transmitter users for equipment with increased power-to-weight ratios can be met by eliminating mains transformers and condensers and replacing them with inverters incorporating mains-voltage semiconductor devices. The relative merits of silicon thyristors and power transistors for this and similar applications are considered Breakdown voltages of ≥800 volts and operating frequencies exceeding 20 kHz, rising in future to 100 kHz or more, are required, together with maximum possible power ratings Thyristors meet the voltage and power requirements, but the ultimate frequency-limiting factor is the minority-carrier lifetime in the wide base. Methods of reducing this with minimum sacrifice or blocking voltage and forward voltage drop requirements are discussed. Diminishing returns limit the practical maximum frequency In power transistors the collector must accommodate depletion-layer spread, since the base-width must be held down to meet frequency requirements. High blocking voltages ...

Abstract: In testing circuit breakers quick determination of the test circuit power factor and its adjustment are necessary to ensure proper test conditions. A fast power factor measuring device using sampling techniques is described in this paper. This device provides an output voltage linearly proportional to the power factor.

Abstract: Power reduction techniques are described for both LSI memory components and systems. These techniques have been verified experimentally for both read-only and random access read/write components using power switching circuits external to the chips. A number of ways to apply on-chip power switching are described. The power switching concept is also described for memory cards and systems that can be organized into blocks.

Abstract: On the basis of simplifying assumptions, equations are derived defining the ripple voltage and operating frequency of the self-oscillating switching regulator in terms of the supply and output voltages, hysteresis voltage, filterchoke inductance, filter capacitance, and a resistance deliberately introduced in series with the filter capacitor. The validity of the equations is checked by testing their predictions against the fundamental differential equations. Design optimisation and limitations are discussed, and an example is given.

Abstract: A brief description is presented of why the power utilities need communication during faults. Wire communication channels can supply this need when suitably protected. The maximum groundpotential rise is needed to select protective equipment. How this transient voltage is generated with its wave shape and duration is explained for a single phase-to-ground fault on a power system. The peak occurs at about one-half cycle time at power frequency following a fault at the critical moment, with a magnitude determined by the X to R ratio. A possibility exists that an even higher voltage results when a phase-to-ground fault changes to a two-phase-to-ground fault after about \frac{1}{3} cycle delay.

Abstract: Primary power source dropouts can cause voltage transients or loss of conditioned power to critical or essential electric power-using equipment. Some of the power loads require controlled transient power, that is , conditioned power which at all times is contained within specified voltage regulation limits. Critical loads which can tolerate a temporary loss of power can be satisfied by the availability of a standby power source. Essential loads which require controlled transient power supply voltage must include in the system configuration of the uninterrupted power supply, an active energy storage element. There are three basic ways in which the controlled transient uninterrupted DC power supply can be configured. The special features of the three systems are compared and the most suitable application for each system is indicated. To illustrate the reduction to practice of one of the controlled transient uninterrupted power supply configurations, a 3KW uninterrupted DC power supply developed for the U. S. Army ECOM by TRW Systems is described indetail.

Abstract: The low power factor of phase-controlled converters when the output voltage is less than the maximum is of-concern in high-power equipment. In a converter consisting of two commutating groups in cascade, the usually low power factor can be improved by firing or gating the thyristors in the two groups asymmetrically. One of the groups is fully advanced (or retarded) to minimize its reactive power, while the other group is controlled to give the desired dc Output. The technique is not recommended for single three-phase bridge converters because of third-hannonic output ripple, second-harmonic line current distortion, and danger of commutation failure. These objections are overcome by combining pairs of three-phase bridges. When regeneration is not required, half of the thyristors can be replaced by diodes, reducing the cost. The method should offer substantial improvement in the power factor of cycloconverter ac motor drives as well as dc motor drives.