Abstract: An automatic power factor correction system, for an electrical power installation drawing varying levels of reactive power, measures an electrical parameter of the power drawn by a load of a power installation using a power measurement integrated circuit, the parameter being capable of indicating a level of reactive power drawn by the load, and couples a combination of capacitors to the power line to compensate for the level of reactive power indicated by the electrical parameter measured. In a first embodiment of the invention, the combination of power factor compensating capacitors is calculated from a signed value of reactive power drawn by the load. In a second embodiment, the compensating capacitor combination is calculated from a value of power factor for the load which is calculated from a ratio of an active power value to an apparent power value.

Abstract: The present invention relates to a method for operating a wind turbine with an electrical generator, drivable by a rotor, for supplying electrical power to an electric grid, in particular to the loads connected thereto. The object of the present invention is to define a method for operating a wind turbine and to provide a wind turbine and/or a wind farm that is capable, even when the output of non-reactive power fluctuates, of reducing or at least of insignificantly increasing the unwanted fluctuation in voltage at a predefined point in the grid compared to the situation with no wind turbine(s). Method for operating a wind turbine with an electrical generator, drivable by a rotor, for supplying electrical power to an electric grid, in particular to the loads connected thereto, characterized in that the phase angle ? is changed in response to at least one voltage measured in the grid.

Abstract: One embodiment of the present invention is a method to control input to an alternating current (AC) induction motor from a power supply that includes steps of: (a) determining a measure of reactive power (VAR) in two input lines to the motor during a time period; and (b) maintaining an SSR (solid state relay) connected in series between the power supply and the motor in a non-conducting state for a subsequent time period, the length of which subsequent time period is determined by analyzing the measure of VAR.

Abstract: A method with which the load current and thus the load moment of an asynchronous motor that is controlled via a phase-controlled two-phase thyristor power controller, can be easily influenced so as to allow a smooth starting operation. According to a first embodiment, the ignition point is determined in the controlled phase in order to adapt the flow angles of the subsequent current half waves. According to a second embodiment, the ignition point of the subsequent current half waves is brought forward in both controlled phases.

Abstract: A switching power supply controller coupled to a first switching power supply circuit and a second switching power supply circuit, the controller sensing voltages provided to the first switching power supply circuit and the second switching power supply circuit. Based on voltages sensed, the switching power supply controller provides signals to operate the second switching power supply in either a first or a second mode of operation. In one of the modes of operation, the second switching power supply includes a transistor which is coupled between a first source of electrical potential and an input terminal of the first switching power supply. If switching power supply controller determines that the magnitude of the first source of electric potential is sufficient to operate the first switching power supply, the switching power supply controller provides a control signal to turn on the transistor continuously.

Abstract: A power converter output voltage regulation method in which sensed output voltages and sensed currents are stored in a memory during a plurality of time intervals. In each time interval the sensed output voltage and the sensed current is compared with the sensed output voltage and sensed currents in time intervals previously stored in the memory. If preceding data are found to match the most recent data, an open loop response is applied. If the most recent data and stored previous data do not match, a closed loop response is applied.

Abstract: A system and method are disclosed for performing energy usage management within a network. The system may include an energy management system, such as a thermostat device, that may be associated with an energy consuming entity, such as a residence. A server may be remotely located from the energy consuming entity and may perform one or more energy curtailment management operations within the network. The server may be in communication with the energy management system over the network. One or more software applications may be stored thereon for remotely controlling the energy management system in accordance with a particular energy curtailment management operation. Additionally, a database may be associated with the server for storing curtailment event information relating to the network. A signal may be transmitted by the server to the thermostat device to alter an offset temperature setting of the thermostat device thereby remotely controlling the operation of the thermostat device.

Abstract: A regulator circuit capable of reducing an increase in an output voltage during a sudden drop in a load current without increasing the power consumption during a steady state. When a current in load IL1 changes suddenly from a large current to a minute current during a steady state, electric charges are charged in capacitor CL1 due to a response delay of the negative feedback control, and an output voltage becomes higher than a target voltage. Then, voltage of node N34 drops, diode 31 gets turned off, and a voltage is held in capacitor 32. As a result, output of comparator 42 changes from a low level to a high level, and n-type MOS transistor 82 gets turned on. In addition, when the voltage between the gate and the source of n-type MOS transistor 50 becomes lower than the voltage of voltage source 71 due to a drop in the voltage of node N34, comparator 72 is also reverted to the high level.

Abstract: A low noise synchronous motor including a permanent-magnet rotor and a stator with at least two pairs of stator poles and corresponding winding further includes an electronic power supply comprising a capacitor that is serially connected to one winding of only one pair of poles to act as a 90° phase shifter. A static switch that is driven by an output of the electronic power device is connected to drive another winding of said two pairs. The static switch is controlled by a sensor detecting the position at the rotor.

Abstract: An automatic power factor correction system, for an electrical power installation drawing varying levels of reactive power, measures an electrical parameter of the power drawn by a load of a power installation using a power measurement integrated circuit, the parameter being capable of indicating a level of reactive power drawn by the load, and couples a combination of capacitors to the power line to compensate for the level of reactive power indicated by the electrical parameter measured. In a first embodiment of the invention, the combination of power factor compensating capacitors is calculated from a signed value of reactive power drawn by the load. In a second embodiment, the compensating capacitor combination is calculated from a value of power factor for the load which is calculated from a ratio of an active power value to an apparent power value.

Abstract: Arrangement for supplying electrical power to a load by means of a transmission path which has been split into two parts

Abstract: Method/apparatus for controlling input to an AC induction motor from a power supply that determines a measure of reactive power in two input lines to the motor from the power supply, and uses that measure of reactive power to control an SSR in series between the power supply and the motor. In one arrangement, a voltage difference between the two input lines and a current in one of the lines is used to determine the measure of reactive power.

Abstract: In a power supply apparatus for discharge surface treatment which uses a green compact electrode as a discharge electrode, allows a pulse-type discharge to take place between said discharge electrode and a workpiece, and forms a film, which is made of an electrode material or a material obtained when the electrode material reacts to a discharge energy, on a surface of the workpiece following three measures are taken. (1) When a discharge voltage detected by the voltage detection means is less than or equal to discharge detection voltage set value which is slightly lower than a power supply voltage, the electric current cut-off means forcibly cuts off an output of the oscillator so that long-time pulse is prevented. (2) A capacitor is connected in parallel with an oscillation circuit of the oscillator, and the long-time pulse is prevented by capacitor discharge. (3) Time that the discharge takes place once is controlled by a timer so that the long-time pulse is prevented.

Abstract: An automatic power factor correction system, for an electrical power installation drawing varying levels of reactive power, measures an electrical parameter of the power drawn by a load of a power installation which is capable of indicating a level of reactive power drawn by the load and couples a combination of capacitors to the power line to compensate for the level of reactive power indicated by the electrical parameter measured. In particular, the system measures the phase angle of the power drawn and calculates a combination of capacitors to connect to the power line to compensate for a measured level of reactive power.

Abstract: An apparatus and method for protecting synchronous generators against off-nominal frequency deviation and alternating forces excitation is provided. Particular application can be found with generators within a power generator plant integrated into a power transmission grid system. A electrical relay system is in operative association with an electrical signal representative of an actual frequency at which the generator is operating and to an electrical signal representative of an actual forcing amount at which the generator is operating. The relay system is adapted to respond to the actual frequency signal and the actual forcing signal such that the relay system compares the actual frequency signal with a predetermined desired frequency range and compares the actual forcing signal with at least one predetermined forcing amount, and selectively alarms the unit operator or trips the generator to an off-line mode depending upon the comparisons.

Abstract: The system includes an enable signal applied to an output AND element. A comparator compares the voltage ratio of selected measured and calculated phase-to-phase or single phase voltages against a threshold value. An AND gate is responsive to a high signal from the comparator and indications of a three pole open condition, a single pole open condition for selected poles, and a loss of potential condition. A high output from the AND gate is applied to a timer, which produces a high output for a short period of time, which controls the output element. The output element provides a blocking signal for the protective elements under particular conditions and a permissive signal under other conditions.

Abstract: Apparatus for determining the frequency of an ac power signal, includes sensing circuitry to sense the ac signal. In a digital implementation of the invention, a double average of the samples is generated by a processor as the sum of the most recent sample, twice the next most recent sample plus the third most recent sample. The least mean square of a running window of the most recent double average signals is generated to avoid discontinuities at the zero crossings and to reduce the effects of noise. The frequency is determined from this least mean square value of the window of double average signals. As implemented in a protective relay, a trip signal is generated if the frequency is out of limits.

Abstract: An automatic power factor correction system, for an electrical power installation drawing varying levels of reactive power, measures an electrical parameter of the power drawn by a load of a power installation which is capable of indicating a level of reactive power drawn by the load and couples a combination of capacitors to the power line to compensate for the level of reactive power indicated by the electrical parameter measured. In particular, the system measures the phase angle of the power drawn and calculates a combination of capacitors to connect to the power line to compensate for a measured level of reactive power.

Abstract: An automatic power factor correction system, for an electrical power installation drawing varying levels of reactive power, measures an electrical parameter of the power drawn by a load of a power installation which is capable of indicating a level of reactive power drawn by the load and couples a combination of capacitors to the power line to compensate for the level of reactive power indicated by the electrical parameter measured. A first embodiment of the system is based on a measured level of current and the effect on the measured level of current of adding compensating capacitors of selected capacitances to the power line. A second embodiment of the system is based on a measurement of phase angle of the power drawn and the addition of a calculated combination of capacitors to the power line to compensate for a measured level of reactive power.

Abstract: A limited-angle power flow transformer implements power flow control in a transmission line of an n-phase power transmission system, where each phase of the power transmission system has a transmission voltage. The transformer has n primary windings, where each primary winding is on a core and receives the transmission voltage of a respective one of the phases of the power transmission system. The transformer also has m secondary windings on the core of each primary winding for a total of m*n secondary windings, where m is less than n. Each secondary winding has a voltage induced thereon by the corresponding primary winding. For each phase, m secondary windings are assigned to the phase. Each assigned secondary winding for the phase is from a different core. For all phases, the secondary windings are assigned from the cores in a balanced manner. For each phase, the secondary windings assigned to the phase are coupled in series for summing the induced voltages formed thereon.

Abstract: A shunt compensating power flow transformer implements power flow control in a transmission line of an n-phase power transmission system, where each phase of the power transmission system has a transmission voltage. The transformer has n primary windings, where each primary winding is on a core and receives the transmission voltage of a respective one of the phases of the power transmission system. The transformer also has n secondary windings on the core of each primary winding for a total of n2 secondary windings, where each secondary winding has a voltage induced thereon by the corresponding primary winding. One secondary winding from each core is assigned to each phase. For each phase, the secondary windings assigned to the phase are coupled in series for summing the induced voltages formed thereon.

Abstract: A computer-implemented protection system is used in a multi-phase electrical distribution network. The system includes a sensor operable to measure an impedance of a device connected to a phase of the distribution network. The device improves coupling of electrical potential from a source to a load. The system also includes a processor connected to the sensor and programmed to receive an impedance measurement from the sensor. The processor automatically calculates a variation in impedance of the device, the variation being based on a ratio of the impedance measurement and a previous impedance measurement. The processor automatically performs a protection analysis of the device based on the impedance variation.

Abstract: A voltage sag generator for alternating current power systems intentionally creates power quality disturbances. The sag generator has a switch-mode impedance between its input and its output. Varying the duty-cycle of the switch-mode impedance causes voltage sags.

Abstract: Apparatus and methods for AC power regulation primarily intended for inductive loads (e.g., fluorescent lights, motors, etc.) which provide substantial reduction in power consumption while also providing a leading power factor, reduced harmonic distortion, reduced crest factor and reduced noise. The system is self-adjusting for a wide range of loads and can reduce power consumption by 25 percent in lighting loads while producing minimal reduction in light output. The system utilizes a Triac and parallel capacitor bank in series with the load. The Triac is turned on in response to a near-zero differential voltage measured across the Triac and is turned off near the peak of each AC half cycle by shunting current around the Triac. The capacitor absorbs the inductive turn-off voltage spike caused by the collapsing magnetic field in the ballast at the instant of Triac turn-off. This energy, in turn, provides longer on-period for the lamp, thereby permitting more light and increased operating efficiency.

Abstract: In a method for predicting harmonic-distortion values for the application of a desired step change of capacitance to an AC system, an initial step change is applied and, from this change, a value of harmonic impedance of the system for each of a number of harmonics is determined. From these harmonic-impedance values corresponding values of damping resistance are, in turn, determined and, using the determined harmonic-impedance and damping-resistance values, corresponding values of an electrical load parameter, preferably load voltage, are determined for the desired step capacitance change. The method is conveniently extended to cover a method and apparatus for applying power-factor correction capacitance, in which the load-voltage values for the various harmonics are evaluated to see if they represent a potential resonance condition and, if so, a step change other than the desired change is applied. Where no resonance is indicated, the originally intended step change is applied.

Abstract: A method and apparatus are provided directed to a synchronous and adaptive capacitor switch controller for minimizing transients in the power factor correction of an electric power distribution system or transmission line. In particular, a capacitor, operatively associated with an electrical bus for distributing electric power, is provided for varying a capacitance on the electrical bus to perform power factor correction. A mechanical switch having a variable switch delay is provided for electrically connecting and disconnecting the capacitor to the electrical bus. A disturbance detector for measuring a voltage disturbance on the electrical bus upon connection and disconnection of the capacitor is further included.

Abstract: A lighting apparatus includes a full-wave rectifier circuit for rectifying an AC voltage from a commercial power source, a smoothing condenser connected is series with an inductor and a diode between output terminals of the full-wave rectifier circuit, a light source unit containing a series circuit of light emitting diodes and connected in parallel with the smoothing condenser, a MOSFET connected in series with the inductor between the output terminals of the full-wave rectifier circuit, and a control circuit for performing switching control of the MOSFET. In particular, the control circuit is constituted such that a voltage across the smoothing condenser is set higher than a peak of an input voltage input to the smoothing condenser through the diode and equal to a total sum of forward voltage drops of the light emitting diodes at a time of igniting the light source, under the switching control.

Abstract: Apparatus and methods for AC power regulation primarily intended for inductive loads (e.g., fluorescent lights, motors, etc.) which provide substantial reduction in power consumption while also providing a leading power factor, reduced harmonic distortion, reduced crest factor and reduced noise. The system is self-adjusting for a wide range of loads and can reduce power consumption by 25 percent in lighting loads while producing minimal reduction in light output. The system utilizes a Triac and parallel capacitor bank in series with the load. The Triac is turned on in response to a near-zero differential voltage measured across the Triac and is turned off near the peak of each AC half cycle by shunting current around the Triac. The capacitor absorbs the inductive turn-off voltage spike caused by the collapsing magnetic field in the ballast at the instant of Triac turn-off. This energy, in turn, provides longer on-period for the lamp, thereby permitting more light and increased operating efficiency.

Abstract: An active digital voltage regulator circuit is a two terminal device that is connected in shunt to first and second power supply input lines. The active digital voltage regulator circuit stores energy during times when the local power supply voltage is greater than a predefined voltage, e.g., during times when the parasitic inductances supplement the local power supply voltage. The active digital voltage regulator circuit uses the stored energy to supplement the local power supply voltage during times when the local power supply voltage starts to collapse, e.g., during periods when inductive losses are preventing the power supply from maintaining the local power supply voltage. Consequently, digital active voltage regulator circuit smooths the local power supply voltage by greatly ameliorating the ripple voltages associated with parasitic inductances and resistances. A control circuit within the regulator circuit is a combination of two self-biasing and off-set nulling power supply monitor circuits.

Abstract: The present invention relates to an electronic switch system for controlling AC power to a load. The switch has ON, OFF and RAMP down modes that can be selected by means of momentary touch switches. When put into the RAMP down mode, the power to the load decreases slowly at a gradual continuous uninterrupted predetermined rate. This switch system has particular utility in brightness control of lamps. It has been found that the use of a lamp controlled by an electronic switch of the present invention often will induce sleep for people that have difficulty going to sleep, particularly young children and older persons. Thus the electronic switch system and devices embodying this system are particularly useful in a method to induce sleep.

Abstract: In an apparatus for control of controller equipment for damping power oscillations in a power line, the controller equipment is serially connected between a first connection point and a second connection point in the power line in an electric network for alternating current. The controller equipment is adapted to serially generate in the power line, dependent on a control order, a damping voltage for damping power oscillations in the power line. Controlling equipment receives sensed quantities of the power network and forms a phase deviation dependent on these quantities. The phase deviation is the difference between a phase angle of a first voltage at the first connection point and a phase angle of a second voltage at the second connection point. The controlling equipment forms the control order dependent on the time rate of change of a function of the phase deviation.

Abstract: Control equipment (CE) for a series capacitor (1) connected into an electric power line (2) has a semiconductor valve (3), which is controllable in both directions, for connection in parallel with the capacitor. An inductor (4) is adapted to form, together with the capacitor, an oscillation circuit in which the semiconductor valve is included. The equipment has control members (PLL, TC) for firing the semiconductor valve for reversal of the capacitor charge and for control of the times (t.sub.p) for the zero crossings of the capacitor voltage (u.sub.C) such that these become substantially equidistant also in the presence of subsynchronous components in the power line current.

Abstract: A microprocessor (42) is coupled to sense the current and voltage in an AC line (11) at a high sampling rate and to determine the power factor. In one embodiment the primary (83) of a transformer (84) is coupled across the power lines, and at least two capacitors (86, 88), forming separate switching paths, are coupled to the secondary (85) of the transformer. High speed switching circuitry under the control of the microprocessor alternately charges and discharges the capacitors (86, 88) at varying frequencies, to alternately store energy from the power lines (11) when the variable load (32) is returning energy to the power lines, and to supply the stored energy back to the power lines when the variable load (32) is absorbing energy from the power lines (11). This corrects the power factor since the frequency of the high speed switching circuitry is varied with the varying reactance of the load.

Abstract: A three-phase rectifier circuit for a capacitive load wherein only small current harmonics occur has, at the rectifier input, an inductance and a capacitor arrangement that compensates the reactive power of the inductance. The capacitors can be individually switchable, for the regulation of the rectifier output voltage.

Abstract: The invention relates to a method and a device for reducing imbalances (.DELTA.V.sub.12, .DELTA.V.sub.23, .DELTA.V.sub.31) in a three-phase network (42) by means of a static compensator. According to the invention, a correction signal (.DELTA.B.sub.12, .DELTA.B.sub.23, .DELTA.B.sub.31) is in each case superimposed on a mean susceptance value (B.sub.SVC), which is produced, of the static compensator, which correction signals (.DELTA.B.sub.12, .DELTA.B.sub.23, .DELTA.B.sub.31) are in each case proportional to an imbalance (.DELTA.V.sub.12, .DELTA.V.sub.23, .DELTA.V.sub.31), which imbalances are determined from measured line to earth voltages (V.sub.01, V.sub.02, V.sub.03) by comparisons, in pairs, of the determined line to line voltages (V.sub.12, V.sub.23, V.sub.31). Imbalances (.DELTA.V.sub.12, .DELTA.V.sub.23, .DELTA.V.sub.31) in the three-phase network (42) can thus be reduced in a simple manner.

Abstract: A power capacitor controller that adaptively and/or automatically determines a variety of operational parameters, including adaptively and automatically establishing the line phase angle correction value; adaptively and automatically establishing the appropriate electrical levels determining connection and disconnection of the capacitor bank relative to the line; adaptively and automatically establishing appropriate guard voltage levels determining connection and disconnection of the capacitor bank relative to the line; automatically determining when the capacitor bank is inoperative; automatically determining when a reverse power line condition and a reverse current line condition exists; automatically determining when a capacitor bank switching operation is a result of multiple capacitor banks on the line, and automatically determining when the operational set points of the controller are reversed.

Abstract: A control circuit for an electrical appliance having an inductive load includes a signal conditioning element, a control element, a power conditioning element, a power adjustment element, and a switching element. The control circuit is sensitive to input received from a sensor which in turn is sensitive to a touch on an outside of a conductive casing of the appliance or a sharp sound. A separate touch pad is used if the appliance has a non-conductive casing. The load is typically a motor for driving a fan unit. The fan unit may be used either independently or as part of an appliance such as a humidifier, dehumidifier, heater, or air purifier.

Abstract: Using a switching circuit (2) for a reactive power compensation device (1), he compensation capacitors of the reactive power compensation device (1) can be switched on with voltage measuring devices (30, 31) which are switched between two phase conductors (3, 4) if the the voltage is the same on both sides of an open phase conductor switch (24). In a preferred embodiment, closing the second phase conductor switch (25) occurs triggered by a delay device (36) following a fixed delay time. In another preferred embodiment, switching on occurs when the voltage is the same between the phase conductors (4,5) on both sides of the second phase conductor switch (25), whereas this condition can be checked with two other voltage measuring devices switched between the phase conductors (4, 5) as well as with another equivalence comparator.

Abstract: Apparatus and methods for AC power regulation primarily intended for inductive loads (e.g., fluorescent lights, motors, etc.) which provide substantial reduction in power consumption while also providing a leading power factor, reduced harmonic distortion, reduced crest factor and reduced noise. The system is self-adjusting for a wide range of loads and can reduce power consumption by 25 percent in lighting loads while producing minimal reduction in light output. The system utilizes a Triac (32) and parallel capacitor bank (58) with the load (22). The Triac (32) is turned on in response to a near-zero differential voltage measured across the Triac (32) and is turned off near the peak of each AC half cycle by shunting current around the Triac (32). The capacitor (60) absorbs the inductive turn-off voltage spike caused by the collapsing magnetic field in the ballast at the instant of Triac turn-off.

Abstract: A power system relay combining the functions of tapchanger control, capacitor control, substation data monitoring and communications.

Abstract: A continuous current type power factor correction circuit in a power device having rectifying means for rectifying an alternating current, a booster converter having an inductor, a diode and a capacitor series connected to an output terminal of the rectifying means, a control switch connected in parallel with the series connection of the diode and capacitor, and a load connected across the capacitor for outputting a boosted direct current to the load according to switching operation of the control switch, and a power factor correction circuit controlling the switching operation of the control switch, the power factor correction circuit, comprising; an off-time controller comparing a first voltage signal with a second voltage signal and generating an off signal in response to the comparison, an on-time controller generating an on signal in accordance with a charge time period of the capacitor, the charge time period being determined from a point in time wherein the off-time controller generates the off signal,

Abstract: When operating, DC arc furnaces generate undesired reactive load fluctuations which are compensated without special compensation reactance by a reactive power controller. As compensation reactance, use is made of inductors, which are always present and via which the arc furnace is fed by rectifiers. A current controller is connected to the rectifiers via a first summer. On the input side, the first summer is further operationally connected to the output of the reactive power controller and, as the case may be, to an AC--AC converter which supplies a signal proportional to the power supply voltage (U.sub.xN). In addition, it is possible to provide an inverter which is connected in parallel with the arc furnace on the DC side and which is operationally connected on the AC side to a feeding AC power supply network (N) via a stabilization transformer or via auxiliary windings of a furnace transformer, and to the output of the reactive power controller on the control side.

Abstract: Apparatus and methods for AC power regulation primarily intended for inductive loads (e.g., fluorescent lights, motors, etc.) which provides substantial reduction in power consumption while also providing a leading power factor, reduced harmonic distortion, reduced crest factor and reduced noise. The system is self-adjusting for a wide range of loads and can reduce power consumption by 25% in lighting loads while producing minimal reduction in light output. The system utilizes a triac and parallel capacitor bank in series with the load. The triac is turned-on in response to a near-zero differential voltage measured across the Triac and is turned-off near the peak of each AC half cycle by shunting current around the Triac. The capacitor absorbs the inductive turn-off voltage spike caused by the collapsing magnetic field in the ballast at the instant of triac turn-off. This energy in turn provides longer on period for the lamp, thereby permitting more light and increased operating efficiency.

Abstract: An active power conditioner for mitigating zero-sequence currents in electrical distribution by items wherein a multi-phase, neutral-forming structure employs a controllable voltage source, which source is controlled by a current-responsive voltage controller, to cancel an equivalent impedance of the multi-phase, neutral-forming structure so that zero-sequence currents are shunted to ground, thereby effectively nullifying the zero-sequence current respective to the source. The multi-phase neutral-forming structure may include multi-phase, neutral-forming autotransformers, zig-zag autotransformers, grounded-wye/unloaded-delta transformers and the like. While zero-sequence fundamental harmonic currents may be selectively shunted to ground, positive- and negative-sequence currents may remain essentially unaffected. The compensating action employed herein may be purely reactive in nature and thus consume little real power.

Abstract: In a method for monitoring and/or control of a plant component (4A, 4B, 4C, 4D) connected to an electric power network (N1, N2), for example a tunable filter for harmonic filtering or a capacitor bank for generating reactive power in a converter plant for high-voltage direct current, products of, respectively, a voltage (U.sub.A, U.sub.B, U.sub.C, U.sub.D) occurring in the plant component and of a current (I.sub.A, I.sub.B, I.sub.C, I.sub.D, I.sub.AC) flowing therethrough are formed, and sine and cosine signals, the frequencies of which are equal to the product of the ordinal number of a selected tone and a fundamental frequency associated with the power network, the products are integrated and the phase difference (.phi..sub.un -.phi..sub.In) and/or the amplitude value (SUn, SIn, respectively) between/for the components of the voltage and the current of the selected tone are formed by quotient generation, multiplication, and summation of the integrated products.

Abstract: This invention provides various methods and techniques for adaptive control of pole-top capacitors to compensate for inductive customer loads along distribution lines together with control of Var flow into supply lines to a distribution substation by a load tapchanging transformer control using measures of said Var flow as a voltage control bias.

Abstract: A circuit for reducing the effects of unpredictable changes in power supply and variations in loading on sensitive equipment, e.g. CT scanning system, to reduce inaccurate readings and protect equipment. The circuit utilizes a network of variable reactances controlled either by manual switches or by a microprocessor receiving inputs from a plurality of monitoring locations within the network.

Abstract: A multilevel convertor having a set of series-connected capacitors and a set of associated series-connected switching elements employs a main control loop which controls some aspect of an AC system, e.g. busbar voltage, by controlling the switching times of the switching elements. The convertor also comprises one or more subsidiary control loops for establishing a desired relationship between mean DC voltage levels on the capacitors. The subsidiary control loops combine first signals proportional to DC voltage levels on the capacitors and second signals proportional to tap currents associated with the capacitor nodes to provide signals which modulate the timing of the switching of switching elements connected to those capacitors which are out of balance, while leaving alone the timing of the switching of switching elements associated with those capacitors which have the required voltage across them.

Abstract: A microprocessor is coupled to sense the current and voltage in a power phase at a high sampling rate such as two hundred fifty-five (255) times per cycle, and to determine the power factor. The primary of a transformer is coupled across the power lines, and at least two capacitors, forming separate switching paths, are coupled to the secondary of the transformer. High speed switching circuitry under the control of the microprocessor alternately charges and discharges the capacitors, at varying frequencies, to alternately store energy from the power lines when the variable load is returning energy to the power lines, and to supply the stored energy back to the power lines when the variable load is absorbing energy from the power lines. This corrects the power factor since the frequency of the high speed switching circuitry is varied with the varying reactance of the load.

Abstract: In one form of the invention, a method for improving power factor in a multiple phase power distribution system coupled to a load is disclosed, comprising the steps of (a) sensing an actual voltage of each of the multiple phases, (b) sensing an actual current being sourced by each of the multiple phases, (c) calculating an ideal current value for each of the multiple phases such that each the ideal current is in phase with a respective one of the actual voltages, (d) coupling at least one energy storage device for sinking current from at least one of the multiple phases wherein the actual current is less than the ideal current and (e) coupling the energy storage device for sourcing current to at least one of the multiple phases wherein the actual current is greater than the ideal current. Other systems, devices and methods are disclosed.