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Showing papers on "Voltage regulation published in 1968"


Journal ArticleDOI
TL;DR: In this paper, the influence of generator voltage regulators on powerline stability is closely scrutinized by analog techniques and it is shown that high-speed control of excitation to maintain constant terminal voltage actually hampers rather than aids damping and power line stability.
Abstract: The influence of generator voltage regulators upon powerline stability is closely scrutinized by analog techniques. Contrary to common concepts, it is shown that high-speed control of excitation to maintain constant terminal voltage actually hampers rather than aids damping and powerline stability. It is further shown that damping and stability are greatly improved by supplementing excitation control with a specially derived function of frequency deviation. Results of the studies are verified in actual performance obtained in field tests.

92 citations


Journal ArticleDOI
01 Apr 1968
TL;DR: In this paper, the effects of the injection of reactive power by static capacitors are discussed, together with the effect of the induction-motor content of the loads, and Graphs summarising critical load voltages and corresponding short-circuit levels for various transformer tap ratios are given and are general in application.
Abstract: The general phenomenon of voltage collapse or instability at the load end of transmission links is introduced with reference to previous work, and the induction motor is seen to be the critical constituent of system loads. The power/voltage and reactive-power/voltage characteristics of power-system loads are predicted and accurately represented by polynomial expressions which are used in the analysis of radial transmission links fed from infinite busbars. Graphs summarising the critical load voltages and the corresponding short-circuit levels for various transformer tap ratios are given and are general in application; these are based on the dV/dZ criterion for voltage stability. It is shown that, although tap changing to raise the load voltage increases the critical length of the link, it also reduces the margin between normal operating voltage and the voltage at the onset of instability. The effects of the injection of reactive power by static capacitors are discussed, together with the effect of the induction-motor content of the loads. The use of the dEs/dVr criterion as advocated in the Russian literature is discussed.

81 citations


Journal ArticleDOI

71 citations


Patent
11 Apr 1968
TL;DR: In this article, the phase detector is connected to the voltage wave source and the current zero crossing pulse source and converts the signals to a DC analog output of the phase relationship between the voltage and current wave and this current is used to control by means of a voltage level operated switch, and an external circuit.
Abstract: A circuit is provided for connection to an AC line and a reactive load which extracts a voltage wave form from the line, the phase of which is adjustable. A pickup to the load extracts a current wave form from the load on the line to the load and converts the current wave form to pulses which are synchronized with the zero crossing or points where the current goes to zero. A phase detector is connected to the voltage wave source and the current zero crossing pulse source and converts the signals to a DC analog output of the phase relationship between the voltage and current wave and this current is used to control by means of a voltage level operated switch, and an external circuit.

37 citations


Journal ArticleDOI
01 Jun 1968
TL;DR: In this paper, the authors examined the theory of the 2-stage voltage transformer and showed that it not only provides a very accurate primary/secondary voltage ratio but also increases the effective input impedance of one of its primary windings to a very high value.
Abstract: The paper examines the theory of the 2-stage voltage transformer and shows that it not only provides a very accurate primary/secondary voltage ratio but also increases the effective input impedance of one of its primary windings to a very high value. It is shown theoretically and experimentally that these characteristics enable inductive voltage dividers to be made which have extremely small errors of voltage division within individual decades and in which the errors due to interconnecting the decades are virtually eliminated. Single-decade dividers having in-phase errors of less than 5 parts in 109 of the input over the frequency band 40–400 Hz have been constructed.

34 citations


Patent
Kazuo Oishi1, Tokuhiro Kurebayashi1
03 Dec 1968
TL;DR: In this article, an OSCILLATOR TRANSFORMER is connected with the STORAGE BATTERY through a switching mechanism, and when the VOLTAGE of the BATTERIY is lower than a predefined value, it is switched to an INTERMEDIATE TAP thereby to prevent the drop of the output VOLUME 7, 2019 VOLUME 6, 2019 output VOLUME 5, 2019 outpour.
Abstract: A CAPACITOR DISCHARGE TYPE IGNITION DEVICE, WHEREIN AN INTERMEDIATE TAP IS PROVIDED ON A PRIMARY WINDING OF AN OSCILLATOR TRANSFORMER INCORPORATED IN A DC-DC CONVERTER ADAPTED FOR BOOSTING THE VOLTAGE OF A STORAGE BATTERY, SAID INTERMEDIATE TAP AND THAT ONE OF THE TERMINALS OF SAID PRIMARY WINDING WHICH IS ON THE POWER SOURCE SIDE ARE CONNECTED WITH THE STORAGE BATTERY THROUGH A SWITCHING MEANS WHICH ARE UNDER THE CONTROL OF A VOLTAGE CONTROL ELEMENT ADAPTED TO DETECT THE TERMINAL VOLTAGE OF SAID STORAGE BATTERY, AND WHEN THE VOLTAGE OF THE STORAGE BATTERY IS LOWER THAN A PREDETERMINED VALUE, THE BATTERY IS SWITCHED TO SAID INTERMEDIATE TAP THEREBY TO PREVENT THE DROP OF THE OUTPUT VOLTAGE FROM SAID TRANSFORMER, WHILE A REVERSE CURRENT FROM SAID PRIMARY WINDING TO THE STORAGE BATTERY BEING STOPPED BY A DIODE.

18 citations


Journal ArticleDOI
TL;DR: In this article, a tap-changing circuit with a tapped inductor carrying a controlled direct current is proposed to prevent tap-to-tap short circuits and provide an additional output voltage level.
Abstract: The control of thyristors used in alternating-voltage regulators employing synchronous tap changing is normally complicated when there are wide variations in load power factor. The modified form of tap changing circuit described here simplifies these control problems and because of the different operating mode produces less distortion in the output waveform. The essential feature of this circuit is that a tapped inductor carrying a controlled direct current is connected in the output circuit of the regulator. This inductor prevents tap-to-tap short circuits and effectively provides an additional output voltage level.

18 citations


Patent
27 Dec 1968
TL;DR: In this paper, the RECTIFIER STACKs are used to connect a power source to the transformer in a high-voltage tank, and the transformer is connected to a LOAD, a CHOKE COIL, and a rectifier stack.
Abstract: A POWER SUPPLY FOR CONVERTING HIGH VOLTAGE ALTERNATING CURRENT INTO HIGH VOLTAGE DIRECT CURRENT COMPRISING A TANK HAVING A TRANSFORMER THEREIN. BUSHINGS EXTENDING THROUGH THE TANK FOR CONNECTING A POWER SOURCE TO THE TRANSFORMER. HIGH VOLTAGE BUSHINGS EXTENDING THROUGH THE TANK FOR CONNECTING A DIRECT CURRENT LOAD TO THE POWER SUPPLY. EACH OF THE HIGH VOLTAGE BUSHINGS HAS ATTACHED THERETO A TERMINAL FOR CONNECTING TO A LOAD, A CHOKE COIL, AND A RECTIFIER STACK. THE RECTIFIER STACKS EXTEND INTO THE TANK AND ALTERNATING CURRENT CONNECTIONS FROM THE TRANSFORMER AND DIRECT CURRENT CONNECTIONS TO THE LOWER END OF THE RECTIFIER STACKS ARE AUTOMATICALLY MADE WHEN THE RECTIFIER STACKS ARE INSERTED INTO THE TANK.

18 citations


Patent
18 Dec 1968
Abstract: A voltage-regulated power supply with standby power capability particularly adapted for use in data-processing equipment and the like is shown to comprise a sealed, rechargeable battery to be connected across a load for determining load voltage and for cooperating in meeting current demands of the load, a direct current energy source arranged to provide charging current to the battery and to cooperate in meeting the current demands of the load, and control means regulating the charge state of the battery for maintaining load voltage within selected limits

14 citations


01 Dec 1968
TL;DR: In this paper, a bibliography of 498 abstracts of literature on high voltage dc power transmission is presented, and an author index is included, based on the LCL (Long Short Term Memory).
Abstract: A bibliography of 498 abstracts of literature on high voltage dc power transmission is presented. An author index is included. (LCL)

12 citations



Journal ArticleDOI
TL;DR: In this article, an ac voltage-regulation method based on the principle of both forced ignition and extinction of thyristors acting as switches was described. This method was found more efficient than the conventional one, assuring a higher power factor for inductive loads.
Abstract: An ac voltage-regulation method is described, based on the principle of both forced ignition and extinction of thyristors acting as switches This method was found more efficient than the conventional one, assuring a higher power factor for inductive loads

Journal ArticleDOI
01 Feb 1968
TL;DR: In this article, a 3-term prime-mover governor was used to improve the dynamic performance of a turbo-alternator, which can be achieved by combining the Integral-of-speed and derivative of speed signals with the conventional velocity signal.
Abstract: Improved dynamic performance of a turboalternator may be achieved by the use of a 3-term prime-mover governor. Integral-of-speed and derivative-of-speed signals can be generated and combined with the conventional velocity signal, which then controls the input power. Transfer functions for the synchronous machine, turbine and governor mechanism are obtained from linear theory, and the frequency responses of the system operating with different prime-mover controller configurations are given on Bode diagrams. Interaction between the prime-mover steam-flow controller and the terminal-voltage exciter-field regulator is ascertained for a range of system operating conditions.

Journal ArticleDOI
TL;DR: In this paper, a number of abnormal system operating conditions should be considered in evaluating generator excitation system performance, including extended periods of operation at other than normal frequency, or voltage, or both, simultaneously.
Abstract: Modem generator excitation systems provide good voltage regulation at normal system frequency and assist in maintaining transient stability during disturbances. However, a number of abnormal system operating conditions should be considered in evaluating excitation system performance. Some of these conditions are extended periods of operation at other than normal frequency, or voltage, or both, simultaneously. These system conditions can cause excessive output from the generator excitation system and impose overloads on the generator and step-up transformer.

Patent
11 Jun 1968
TL;DR: In this article, a power supply for use with a high voltage device, such as an image amplifier tube, is disclosed wherein the frequency of a tunable oscillator is adjusted so that there is optimum power translation through the transformer of the power supply to a voltage multiplier network, which may include a plurality of voltage doublers connected in series.
Abstract: A power supply for use with a high voltage device, such as an image amplifier tube, is disclosed wherein the frequency of a tunable oscillator is adjusted so that there is optimum power translation through the transformer of the power supply to a voltage multiplier network, which may include a plurality of voltage doublers connected in series. The multiplied voltage is used for supplying the high voltage electrode of the device utilized such as the anode screen element of an image amplifier tube. A voltage divider network is provided to receive a portion of the multiplied voltage and includes a plurality of potentiometers for selecting various operating voltages which may be applied to various electrodes of a high voltage device, such as electronic lens elements of an image amplifier tube. A plurality of low voltage switches are utilized with the voltage divider network for changing the operating levels of the device such as the magnification of an image amplifier tube.

Journal ArticleDOI
TL;DR: In this paper, several techniques for achieving high-accuracy current regulation with tap changer controlled silicon rectifier dc power supplies are described, including partial range saturable reactors to providevernier control between tap changing transformers and a fast response feedback amplifier-driver to give essentially continuous highaccuracy (0.1 to 0.5 percent) current regulation.
Abstract: Typical large silicon rectifier dc power supplies for electrochemical lines have ratings of 20 000 to over 300 000 amperes, at voltages of 50 to 1000 volts. The operating efficiency of such installations is of major economic importance, and experience has shown that the use of high-accuracy current regulation can substantially improve efficiency. Regulation is required to compensate for ac supply fluctuations and electrochemical cell or potline characteristics variations. Underload tap changing transformers provide an economical and highly efficient means of varying the rectifier dc output voltage. Control resolution, however, is relatively limited due to the finite voltage steps between taps, and precautions must generally be taken to avoid unnecessary tap changer operations in order to achieve reasonable operating periods without contact maintenance. Several techniques for achieving high-accuracy current regulation with tap changer controlled silicon rectifier power supplies are described. One approach utilizes partial range saturable reactors to provide vernier control between tap changer steps and a fast response feedback amplifier-driver to give essentially continuous high-accuracy (0.1 to 0.5 percent) current regulation. Another method controls the tap changer by means of an error integrating or reset amplifier technique which ignores minor short-tenn current fluctuations but maintains the average value over several hours of operation to within a fraction of a percent of the preset value.




Patent
01 Aug 1968
TL;DR: In this paper, a power responsive overload sensing and protective circuit for the protection of an active electrical device developing an output to a load with resistive means between two electrodes of the active device, a resistor between an electrode of the device and the load and with the resistor, the load connected in series between a voltage power supply and ground.
Abstract: A power responsive overload sensing and protective circuit for the protection of an active electrical device developing an output to a load with resistive means between two electrodes of the active device, a resistor between an electrode of the device and the load and with the resistive means, the resistor, and the load connected in series between a voltage power supply and ground. The circuit includes a voltage value threshold level sensing detector having two inputs connected across a section of the resistive means and the resistor, and an output connected to a clamp device in turn connected between a signal input path to the active device and ground. The resistive values of the resistive means and the resistor are value selected to insure the development of predetermined voltage ratios between the voltage supplied and the voltage across the load. In one embodiment resistor values of the resistive means are so chosen that the voltage developed across one of them is quantitatively substantially equal to the voltage developed across the resistor connected to the load when the voltage developed across the load is approximately equal to one-half the voltage supplied.

Patent
03 Sep 1968



Patent
18 Nov 1968
TL;DR: A voltage regulator serving a DC power supply controls the peak voltage of an input AC waveform by momentarily opening a switch connected in series with the AC source during periods when the input voltage exceeds a desired reference voltage related to the output voltage of the supply as discussed by the authors.
Abstract: A voltage regulator serving a DC power supply controls the peak voltage of an input AC waveform by momentarily opening a switch connected in series with the AC source during periods when the input voltage exceeds a desired reference voltage related to the output voltage of the supply. The action of the switch creates notches centered in each half cycle of the AC waveform whose width is inversely related to the magnitude of the peak voltage applied to the DC supply and to the output voltage applied to the load. Control of the average or RMS voltage, as well as random peak voltages, may also be accomplished using a similar technique.

Journal ArticleDOI
TL;DR: In this paper, the authors discuss methods of extending and improving the MIL-STD-220A technique for measuring the insertion loss of filters for frequencies as low as 14 kHz and under loads as high as 200 amperes.
Abstract: The most important requirement of a power-line filter is its insertion loss under load. This paper discusses methods of extending and improving the technique of measuring insertion loss as specified in MIL-STD-220A. It discusses present equipment limitations in MIL-STD-220A that restricts full-load tests to frequencies above 100 kHz and limits maximum current to 100 amperes. However, it is realized that MIL-STD-220A is the only available specification at present. Therefore, the paper discusses methods of extending the MIL-STD-220A technique for measuring the insertion loss of filters for frequencies as low as 14 kHz and under loads as high as 200 amperes. A new buffer network that allows such measurements is described. In addition, a method is discussed for improving voltage regulation and reducing distortion of the power-line waveshape caused by power filters. These are two parameters which have been totally ignored when specifying power filters and which have been found to cause considerable electrical problems after installation.

Patent
17 Dec 1968




Patent
03 Apr 1968
TL;DR: In this paper, a transformer having on-load tap changing on its primary winding for coarse voltage control has a resistor R8 variably shunted by a pair of reverse parallel thyristors for fine voltage adjustment.
Abstract: 1,108,089. Tap changing transformers. J. H. CALVIOU, R. G. CLITHEROE and D. D. SILVESTER. 3 Nov., 1966 [17 Sept., 1965], No. 39790/65. Heading H2H. A transformer having on-load tap changing on its primary winding for coarse voltage control has a resistor R8 variably shunted by a pair of reverse parallel thyristors for fine voltage adjustment. Inter tap circulating current is limited by a resistor Z. Controls for the fine and coarse voltage variations may be ganged to provide a smooth transistor. The thyristors are fired by pulses having a high frequency relative to that of the supply e.g. 3 kc./s. with a mark space ratio of 1 : 15.