Showing papers on "Voltage regulation published in 1974"

Optimal Load Flow with Steady-State Security

Abstract: The Dommel-Tinney approach to the calculation of optimal power-system load flows has proved to be very powerful and general. This paper extends the problem formulation and solution scheme by incorporating exact outage-contingency constraints into the method, to give an optimal steady-state-secure system operating point. The controllable system quantities in the base-case problem (e.g. generated MW, controlled voltage magnitudes, transformer taps) are optimised within their limits according to some defined objective, so that no limit-violations on other quantities (e. g. generator MVAR and current loadings, transmission-circuit loadings, load-bus voltage magnitudes, angular displacements) occur in either the base-case or contingency-case system operating conditions.

Transient Oscillations in Multiwinding Transformers

Abstract: A method of calculating voltage oscillations in transformer windings during impulse test is presented.

Voltage regulating system

Abstract: In a voltage regulating system, a transistor switching circuit is connected to a voltage sensing circuit which detects a battery voltage and to a lamp. And at least when the voltage sensing circuit becomes disconnected from the battery, the transistor switching circuit is switched on to energize the lamp to inform a driver of the disconnection.

Digital power control

Abstract: A digital power control utilizing zero voltage switching of silicon controlled rectifiers and achieving full isolation of the load from the control circuitry. A thermistor is employed to determine the temperature of the load and a voltage step generator is utilized in conjunction with the thermistor to effect a control of the number of cycles of power to apply to the load.

Calculating Electrostatic Effects of Overhead Transmission Lines

Abstract: This paper presents an approach to predict ground-level electrostatic effects from overhead power transmission lines using the voltage gradient at ground level Objects like vehicles and animals are represented by Norton equivalent networks The advantages in using this method are 1) accuracy in predicting induced short-circuit current, ?sc, open-circuit voltage, ?oc, and capacitance of object to ground, Cog, and 2) simplicity in needing only simple slide-rule computations that are practical in the field

DC to DC Voltage converter

Abstract: A DC voltage source of amplitude below the DC voltage requirement of a load to be energized drives a pair of complementary transistors which are alternately turned on and off to apply supply voltage alternately to each of two capacitors connected in series. The sum voltage of the two capacitors is applied, in one embodiment, directly to a voltage regulator and filtered and, in another embodiment, is added to the DC source voltage prior to being regulated and filtered. The converter output is capacitively coupled to the DC supply voltage, thus furnishing a common AC connection.

AC-DC voltage regulator

Abstract: AC-DC voltage regulation is achieved utilizing, among other components, a series pass control element which is serially connected to a detector and filter output stage and between circuit input terminals and an output load. A rectified input voltage is applied to the series pass control element which controls the required amount of current flowing into a load every 1/2 cycle of the input signal. This current is, in turn, detected and filtered to provide the regulated DC output voltage. A voltage sensor is connected to the output of the series pass control element and in parallel with the detector and filter stage; this sensor breaks down at a predetermined level of series pass voltage to, in turn, generate a feedback control voltage. This control voltage is fed back to a current controlled switch which is connected in shunt with the series pass control element. This current controlled switch responds to the feedback voltage to accordingly limit the current conduction in the series pass control element to precisely the amount required by a varying load connected to the circuit output terminal. Thus, voltage regulation is achieved with a maximum AC-DC conversion efficiency and a minimum power dissipation.

Electric motor transient voltage suppressing circuit

Abstract: An electric power distribution system or an electric device, such as a motor, having a relatively low voltage class of insulation on the conductors or windings thereof is provided with a transient voltage suppressing circuit that is operable to prevent undesirable voltage peaks from being applied to the insulation. Due to the voltage distributing and stabilizing effect of the suppressing circuit, the heat dissipating characteristics of motor windings, combined with the circuit, may be improved and the long-term insulation life of the motor is thereby made more reliable.

Optimum battery reconnect for a field controlled electric vehicle

Abstract: An electric vehicle having a field controlled direct current drive motor powered by batteries which are connectable in a high voltage and a low voltage configuration to change the speed range of the drive motor. Switching of the batteries between the high and low voltage connection is accomplished to provide a relatively smooth transition in both directions and to provide for optimum performance and efficiency. Logic is provided to determine the minimum speed at which high voltage operation is feasible and for initiating switching to the high voltage connection at the determined minimum speed. The minimum speed for operation at the high battery voltage connection is determined as a function of battery open circuit voltage, battery resistance, armature resistance, armature current and field flux. When for the known parameters operation at the high voltage connection is possible, the batteries are switched to the high voltage level. A throttle is provided for controlling the speed of the electric vehicle. At certain lower throttle settings, when the batteries are switched from the low voltage connection to the high voltage connection, the field current is varied to match the new torque at the high voltage connection with the torque previously obtained at the low voltage connection. At certain higher throttle settings, it is not practical to match torque before and after switching when high performance is desired. At these higher throttle settings, torques are not matched and batteries are switched to the high voltage connection at the minimum speed allowing for adequate vehicle control. The torque in the new high voltage connection is then greater than the torque in the prior low voltage connection giving high performance and rapid acceleration.

Method of making a reference voltage source with a desired temperature coefficient

Abstract: A temperature stability of a high order is obtained by voltage divider trimming in a circuit in which a common current supply feeds a first branch containing one or more Zener diodes and a second branch containing a voltage divider composed of ohmic resistances, from the tap of which the output voltage is taken, by provision of a circuit configuration meeting one design criterion and trimming an output voltage divider to meet, at a single reference temperature, another design criterion and thus to set both the designed output voltage and the designed temperature coefficient, independently of the scatter of the characteristics of the diodes in the circuit.

Regulated power supply utilizing a halfwave switch

Abstract: A regulated power supply for a xenon flash tube utilizing a triac as a voltage regulating device and output capacitors as energy storage devices is disclosed. The triac is controlled by a zero voltage crossover AC trigger which is connected to the gate of the triac. The zero voltage crossover AC trigger senses the voltage across the triac and fires the triac at or near zero voltage crossover for preselected half cycles. The triac comes on at the beginning of a half cycle and stays on until it commutates off at the end of the half cycle. This firing of the triac allows the output capacitors to charge to a desired energy level. Flashing, and thus discharge of the capacitor through the tube, will occur only after application of a starting pulse from a starting circuit which is connected to the tube. An output circuit comprising the output storage capacitors and an output voltage sensing means is also provided. A step-up transformer is connected between the triac and the output circuit. A power factor improvement capacitor is connected across the primary winding of the transformer and an extension winding. A voltage comparator is connected between the output voltage sensing means and the zero voltage crossover AC trigger. The comparator compares the output voltage to a reference voltage, and when the output voltage falls below the reference voltage, a signal is passed to the zero voltage crossover AC trigger which in turn fires the triac.

Arrangement for feeding a DC load circuit from single phase or polyphase AC voltage mains with economizing of idle power consumption of load alternating current

Abstract: The arrangement includes a mains transformer having a primary winding and a secondary winding, with the secondary winding being connected to a load circuit including a full wave rectifier, smoothing devices, and at least one positively quenchable, or positive cut-off, controlled semi-conductor rectifier associated with a respective control device. The smoothing devices consist of at least one condenser, at least one choke and at least one filter tuned to double the frequency of the AC voltage mains. The magnitude of the alternating or direct current, available on the secondary side of the mains transformer in the form of current or voltage, is controlled by one or more positively quenchable controlled semi-conductor rectifiers, and the control device controls the controlled rectifier or rectifiers by pulse width modulation thereof to maintain the time slope of the power in the load circuit substantially in phase with the slope of the power, fluctuating with twice the mains frequency about the constantper-unit-of-time mean load power, of the load alternating current which is in phase with the mains AC voltage. In one embodiment, the current flowing from the AC voltage mains through a full wave rectifier into the DC load circuit is maintained constant and an AC voltage, of twice the mains frequency, is superposed on the DC voltage. In another embodiment, the DC voltage of the DC load is maintained constant and alternating current of twice the mains frequency is superposed on the direct current.

Semiconductor controlled ignition systems for internal combustion engines

Abstract: To improve the operation of semiconductor control ignition systems under widely varying supply voltage conditions, a voltage divider having a division tap point is connected in parallel to the main switching part of the switching transistor of the ignition system, and a voltage breakdown element, typically a Zener diode is connected from the tap point to the control electrodes of the semiconductor switch to provide an additional control voltage thereto if the voltage at the tap point exceeds a value leading to breakdown of the breakdown device (Zener diode); the main control circuit for the main ignition transistor may be conventional.

Circuit for soft-starting electric load comprising temperature sensitive diac

Abstract: A circuit for triggering a bidirectional thyristor having a capacitor charged from an ac source includes a semiconductor thermally sensitive switch having a break-over voltage dependent upon a temperature and applied with a voltage across the capacitor. Upon the closure of an ON-OFF switch, the capacitor voltage reaches the break-over voltage to break the semiconductor switch over to turn the thyristor on at a large firing angle resulting in a current flowing through a load. Then the semiconductor switch is heated by a heating resistor connected across the load to decrease in the break-over voltage to decrease the firing angle of the thyristor until a steady-state current flows through the load.

Adapter for automatically adapting dc equipment for energization by a first or second ac voltage of different amplitudes

Abstract: DC equipment requiring a determined operating voltage is adapted for energization by a first AC voltage, or a second AC voltage having twice the amplitude of the first AC voltage. Rectifiers rectify the AC voltage and charge an output capacitor connected across the terminals furnishing the operating voltage. A voltage doubler capacitor is provided as is a thyristor which is responsive to a second rectified voltage and connects the voltage doubler capacitor to the rectifier-output capacitor circuit for voltage doubling purposes when the AC voltage is the first AC voltage. A number of full-wave and half-wave arrangements are shown.

Cable television substation regulated power supply with ripple suppression

Abstract: A voltage regulating circuit in which the suppression of the ripple component of the output voltage is maintained at input voltage levels insufficient to support the regulation of the steady output voltage component. The ripple suppression is achieved at low input voltage levels without additional active devices. Through incorporation of a resistor in a circuit location not normally including a resistor, and by appropriate selection of component values, the ripple suppression at low input voltage levels is achieved without appreciable deterioration of the output voltage regulation under normal operating conditions.

Remote voltage sensor for power system regulation

Abstract: In an alternating current electric power system subject to rapid load voltage regulation as a result of variations in reactive load current, reactive load current compensation is provided by fixed capacitors and inductors in parallel with the load, the inductors being in series with static switches which are phase controlled to continuously maintain the net reactive compensating current substantially equal and opposite to the reactive component of load current. Compensation control determines firing time of the static switches in accordance with the magnitude of reactive load current and regulating means additionally controls firing time to maintain line current and voltage at a selected line location substantially in phase coincidence. A reactive load current sensor and a current angle sensor each utilize a signal voltage representative in phase and magnitude of line-to-neutral voltage at a high voltage "critical bus" location but derived from line-to-line voltage and line current at a remote low voltage system location.

Low cost switching high voltage supply

Abstract: A switching high voltage supply of the type which includes the secondary of a high voltage step-up transformer in series with a DC high voltage power supply, such as for providing different high voltages to a cathode ray tube, includes a capacitor in series with the primary to establish DC voltages that result from random duty cycles and variable DC input levels, the capacitor voltage being fed to the regulation or control input of the DC high voltage supply, whereby DC voltages are coupled by the capacitor to the high voltage supply and AC voltages are coupled through the high voltage transformer. In a second embodiment, the transformer has two secondaries each in series with a high voltage supply controlled by the DC voltage of the capacitor, to provide related, switched high voltages, such as for the anode and the focus of a beam penetration cathode ray tube.

D.C. voltage transformation in high tension systems

Abstract: A transmission substation for transforming a high D.C. voltage over an intermediate three phase A.C. network into a lower D.C. voltage. The substation includes an arrangement of inverters and rectifiers for effecting the transformation with reduced losses. Also encompassed is a similar reversed arrangement for stepping up from a lower D.C. voltage to a higher D.C. voltage.

Circuit for converting alternating current voltages to a constant magnitude direct current voltage

Abstract: An AC-DC regulator circuit is disclosed that is suitable for providing a constant magnitude, minimal ripple DC supply voltage in response to AC line voltages having varying peak amplitudes. The magnitude of the output voltage of the regulator is detected and restricted from exceeding a predetermined value by a feedback circuit employing a regenerative mode of operation. The resulting regulation provides a minimal ripple, constant magnitude supply voltage that may be applied to loads that are sensitive to voltage magnitude variations.

Device for compensating AC power source voltage

Abstract: The power source voltage is detected beforehand through a filter and phase shifter. When the detected voltage reaches the reference voltage through comparison of the detected voltage and the reference voltage, the conduction phase is controlled by turning a phase-controlled rectifier connected in series with the power source circuit, and the amount of the power source current is controlled with respect to time to compensate the effective primary terminal voltage of the power source transformer. When the power source voltage is high, current flows for a short. And when it is low, current flows for a longer period of time.

Voltage condition monitor

Abstract: A device for monitoring a variable voltage supply level is disclosed. The monitoring device functions to supply a signal which may be used to shut-down that equipment being supplied and/or drive an indicating device when the voltage level is below a trip voltage and, when the voltage level exceeds the trip voltage to provide a signal which may be used to reconnect the equipment circuit. The monitoring device includes a pair of low power generators each of which produce a digital signal. The digital signal of one generator varies more than the digital signal of the other generator with changes in applied voltage. The two digital signals are compared by a low power circuit and voltage level information is determined.

Dynamic reference voltage generator

Abstract: A reference voltage generator for generating reference voltages for use in charge-coupled devices includes a means for generating a charge whose magnitude lies between a first charge representing a number in an n-dimensional logic system and a second charge representing another number in an n-dimensional logic system, comparison means electrically coupled to the means for generating a charge, the comparison means generating a voltage representative of the charge and comparing the voltage with an instantaneous reference voltage to provide an indication of the relative magnitudes of the voltage and the instantaneous reference voltage, and feedback means electrically coupled to the comparison means for producing an instantaneous reference voltage and including a means for providing an incremental adjustment to the instantaneous reference voltage in response to the indication of relative magnitude, the incremental adjustment serving to bring the value of the instantaneous reference voltage closer to the value for the voltage.

Controllable high voltage source having fast settling time

Abstract: A high voltage dc stepping power supply for sampling a utilization device such as an electrostatic analyzer has a relatively fast settling time for voltage steps The supply includes a waveform generator for deriving a low voltage staircase waveform that feeds a relatively long response time power supply deriving a high output voltage generally equal to a predetermined multiple of the input voltage In the power supply, an ac voltage modulated by the staircase waveform is applied to a step-up transformer and thence to a voltage multiplier stack to form a high voltage, relatively poor replica of the input waveform at an intermediate output terminal A constant dc source, applied to the input of the power supply, biases the voltage at the intermediate output terminal to be in excess of the predetermined multiple of the input voltage A fast shunt regulator responsive to the input signal provides an output which is a faithful high voltage reproduction of the staircase waveform The shunt regulator includes a solid state shunt device connected to the intermediate output terminal via a dropping resistor The supply output is taken from the junction of the resistor and the shunt device

A New Decoupled Load Flow Method

Abstract: A quick, reliable and new method for solivng the load flow problem in electrical power systems is presented. It is called the decoupled voltage vectors and Newton's method. The method has advantages over Newton' s method in terms of computer storage, speed and reliable convergence. It also has advantages over all other known methods in terms of computer storage, and is as reliable convergent and accurate as the voltage vectors method.

Fail-safe high voltage protection circuit

Abstract: A fail-safe high voltage protection circuit for a television receiver includes means for rectifying pulses developed in the high voltage transformer for developing a direct current voltage proportional thereto for providing an additional bias voltage for the automatic frequency control (AFC) transistor. If the developed high voltage pulse becomes excessive, the corresponding increased bias supplied to the AFC transistor causes an increase in the horizontal oscillator frequency resulting in an unviewable raster.

Line voltage monitor

Abstract: A line voltage monitor for monitoring the voltage applied to electrical equipment and for providing an indication or protective disablement of the equipment in the event excessive variations occur in the line voltage. The line voltage monitor includes a steady state voltage sensing means and a transient voltage sensing means for detecting both types of voltage variations.

Voltage regulator control circuit

Abstract: A voltage regulation control circuit for a magnetically-coupled inductive discharge switching regulator suitable for use in an automotive electrical system provides a regulated output voltage isolated from an unregulated input potential source and controls the rate of energy transfer from an inductor to a capacitor in accordance with the unregulated potential source and the regulated output voltage.

Frequency reduction and power control circuit for thyristor line controllers

Abstract: A circuit for a thyristor line controller interconnecting an alternating current voltage generating power source to a load that controls the amount of power delivered to the load and reduces the fundamental frequency component to f/n, where f is the frequency of generated voltage, and n is an integral number.

Power factor correcting means

Abstract: A power factor correcting means for connection to an AC voltage network includes a transformer with high voltage terminals for connection to the network and low voltage terminals. A capacitor battery is provided for connection to the network, and a controllable inductive element is connected to the low voltage terminal of the transformer. The capacitor battery includes a first part connected to the high voltage terminal of the transformer, and a second part connected to the low voltage terminal of the transformer. The total rated power of the capacitor battery is substantially as great as the maximum reactive power of the inductive element, and the rated power of the second portion of the capacitor battery is between 0.3 and 0.7 times as the maximum reactive power of the inductive element.