Abstract: A multimeter instrument for measuring variables, such as electrical current, voltage, or resistance includes touch-sensitive zones for selection of the variable to be measured. The measurement circuit associated with the variable selected with the aid of touch-sensitive selection zones is activated by the zone selected.

Abstract: An electric power meter measures the value of an electrical power parameter, e.g., Universal Apparent Power or Universal Power Factor, of an electrical power signal in the time domain by: calculating a first instantaneous power component as the product of an instantaneous voltage signal and an instantaneous current signal of the electrical power signal, carrying out a relative phase shift between the instantaneous voltage signal and the instantaneous current signal; and calculating a second instantaneous power component as the product of the relatively phase-shifted instantaneous voltage and instantaneous current signals. The first and second instantaneous power components are then RMS averaged to determine their respective magnitudes. Both of the calculated magnitudes are then used to determine the value of the electrical power parameter. The method can alternatively be implemented in the frequency domain to produce equivalent measurement values.

Abstract: A power transfer arrangement is provided for supplying power from a generator to the electrical system of a building in the event of a utility power interruption. The power transfer arrangement has a power transfer switching mechanism adapted for interconnection with the building electrical system and includes a cabinet having panel structure provided with various electrical components for transferring power to various load circuits. The power transfer arrangement is improved by a generator status information display mounted on the cabinet for separately measuring and simultaneously displaying actual wattage and voltage supplied by the generator to the load circuits.

Abstract: The present invention is a voltage detector that is capable of measuring AC voltages, especially the high voltages encountered by electric utility linemen, with improved accuracy. To obtain these improvements in accuracy the present invention includes a novel circuit, which can be incorporated into a standard digital voltage detector. This circuit is able to accurately determine the magnitude of external capacitive reactance, which allows the voltage detector to compensate for variances in the external capacitive reactance that, if uncompensated, could adversely affect the voltage measurement; consequently, this invention provides the user with an AC voltage detector having improved accuracy characteristics.

Abstract: Disclosed is a method for detecting saturation of a current transformer. The method determines whether or not a change of a secondary current generated in a current transformer is due to the saturation of the current transformer.

Abstract: An exemplary embodiment of the invention is a method for evaluating jitter of a phase locked loop circuit generating a phase locked loop output signal. The method includes generating a test initiate signal and generating a trigger signal in response to the test initiate signal. The trigger signal is synchronized with the phase locked loop output signal. A disturbance signal is generated to induce jitter in the phase locked loop output signal. The jitter in the phase locked loop output signal is then evaluated.

Abstract: The invention relates to an electricity meter with signal channels that are passed to a digital signal processing device and each of which has a multiplexer with downstream analog/digital converter. Voltage signals of an electrical consumer can be connected to a first input of the analog/digital converter of the first signal channel, and current signals of the electrical consumer can be connected to a first input of the analog/digital converter of the second signal channel. In order to allow the meter to be used without any circuit variation both as a four-conductor meter and as a three-conductor meter, one of the voltage signals can be connected to a second input of the analog/digital converter of the first signal channel.

Abstract: An apparatus for metering electrical energy over a predetermined range of voltages within a single meter. The meter includes a divider network for dividing the voltage to generate a divided voltage. The divided voltage is substantially linear with minimal phase shift over the wide dynamic range. A processing unit processes the divided voltage and a current component to determine metered electrical power. A power supply receives the voltage component and generates a supply voltage from the voltage component over the predetermined range to power the processing unit. The power supply may include a transformer having first, second and third windings, so that the voltage component is provided to the first winding and the second winding defines the output of the power supply. A switching member is connected to the first winding for permitting and preventing the flow of current through the first winding.

Abstract: A device for measuring power, or other circuit parameters, of an alternating current load. The device has an ammeter and voltmeter for measuring voltage across the device and current through the device. The device also has a known impedance element that is switchably connected across the load. The ammeter is used to provide a second current measurement with the impedance so connected. These measurements, together with the known impedance value, are use to calculate power, the power factor, impedance, or some other parameter associated with the load.

Abstract: An electronic energy meter register which, in one aspect, is configured to perform load profile recording in a manner which eliminates a need for a back-up battery is described. In other aspects, the present invention is a routine of operating a meter register for providing a cost savings and/or productivity gain when a utility customer relocates and for ensuring that load control commands are effectively executed. The register, in one embodiment, is configured to be coupled to a meter including an eddy current disk and shaft which rotate in response to the rate of energy consumption by a load being metered. The register, in the one embodiment, includes a microprocessor, a non-volatile memory, and a disk sensing optics assembly.

Abstract: Disclosed is a method and arrangement for use in an electrical utility meter, the electrical utility meter operable to be connected to a plurality of electrical service types. The arrangement is operable to identify a present service type, the present service type being one of the plurality of electrical service types to which the electrical utility meter is connected. The arrangement comprises: conversion circuit for obtaining measured voltage magnitude and phase angle data for a plurality of phases in a polyphase electrical system; a memory; and a processor connected to said memory and said conversion circuit. The processor is operable to execute programming steps stored in the memory to receive the measured voltage magnitude and phase angle data from the conversion circuit and identify the present electrical service type based on the measured voltage magnitude and phase angle data.

Abstract: Current and voltage space vectors of the positive sequence system are formed from phase current and phase voltage sampling values of an electric power supply system, and power quantities of the positive sequence system are derived from them. System frequency components are eliminated from these power quantities by a least squares estimate, thus forming a measured active power quantity of the positive sequence system and a measured reactive power quantity of the positive sequence system. By forming quotients with a measured current quantity of the positive sequence system, also obtained using the least squares estimate, impedance values of the positive sequence system are also obtained. These are tested for monotony and abrupt changes and a suspected oscillation signal is formed, if applicable.

Abstract: A three-phase clamp-type power meter comprises a main body suitable to be held by hand during operation, a clamp assembly to clamp around an external power line to measure the current flowing in the power line, two test terminals on the main body for connecting two external power lines to measure a voltage across them, an operating unit for generating a result from the current and the voltage measured through the clamp assembly and the two test terminals with a memory unit for storing the result, and a display unit for displaying at least one of the current, the voltage and the result.

Abstract: An electricity meter contains analog/digital converters to transform input analog voltages and currents into sampled digital values. A first high speed processor derives auxiliary magnitudes from the sampled digital values without intermediate storage. The auxiliary magnitudes, which do not have any direct physical significance, are provided to a lower speed second processor, which utilizes the auxiliary magnitudes to determine various desired parameters and functions of the input voltages and currents.

Abstract: An electrical energy meter is provided with snap fit interlocking parts that eliminate the need for screws or fasteners. The current sensor, located within the meter, has a plurality of current conductors and a notched blade attached to each current conductor that functions as an interlocking component to the meter base without the need for additional fasteners. A circuit board used by the meter is attached to a plurality of integral posts projecting from the base and the periphery of the circuit board has a pair of spaced notches for connection to the ends of a radial communications antenna without the requirement for additional hardware.

Abstract: First and second 1-bit A/D converters convert respective input voltages being in direct proportion to voltage and current of a measurement system into respective 1 bit codes. First and second up-down counters whose up/down count in respective clock terminals are controlled in accordance with respective 1 bit codes which are output from the first and second 1-bit A/D converters, and output A/D converted values of the respective input voltages. A latch holds data one clock prior to currently input data and outputs the data. An adder-subtractor adds and subtracts respective output data of the first and second up-down counters and a numerical value 1 to and from output data of the latch under control of respective output data of the first and second 1-bit A/D converters and an exclusive OR value of the respective output data and outputs arithmetic data which being in proportion to a product of the respective input voltages to the latch. An adder integrates the output data of the latch.

Abstract: A universal electronic energy meter for measuring electrical energy usage of a circuit having a 4-wire service is disclosed. The universal meter is operable with both 4-wire wye and 4-wire delta services without modification to the meter's hardware or software. The universal meter is further operable over a wide range of standard service voltages that are supplied in connection with 4-wire services. The universal meter includes a voltage divider network that senses the line voltages from the circuit and scales the line voltages to a voltage suitable for processing by the meter. The scaled voltage has a maximum peak-to-peak voltage irrespective of the particular standard service supplying the electrical energy to the circuit, and therefore, the voltage divider network is not reconfigured to accommodate a wide range of service voltages. The voltage divider network includes resistive dividers that scale the line voltage to provide a linear voltage with minimal phase shift.

Abstract: A method and apparatus for receiving, monitoring and characterizing network power information in real time through the use of a specialized display system. A processor receives three phase current and voltage information from a network power relay, converts and scales that data into a two-dimensional vector having coordinates that are represented by, and displayed as, a single pixel on a display screen. The repeated monitoring provides a Feature Map (FM) of the network system that can be easily read and understood by operating personnel.

Abstract: In a method of calculating an electric power by digitalizing a voltage signal and a current signal of an electronic watt-hour meter and multiplying digitalized signals, precision of an electric power calculation is improved by a circuit arrangement suitable for use in an IC mainly composed of a digital circuit with a small analog scale. A voltage signal and a current signal are inputted into analog to digital conversion means composed of a sigma-delta modulation circuit and the like, respectively, and a moving average of outputs from the analog to digital conversion means is determined by moving average processing means as a low-pass filter and then voltages are multiplied by currents. An analog scale for sigma-delta modification is small. Additionally, the circuit arrangement is reduced by the employment of the low-pass filter due to the use of the moving average. Further, an electric power can be calculated with a high precision.

Abstract: A process for measuring electricity consumption, especially suitable for small consumers, comprises the steps of continuously measuring consumer current, integrating the current with time to obtain a value (A.h) relating to consumption; adjusting the integration in function of the voltage of the network to obtain an adjusted value (A.sub.v.h) proportional to a preestablished unit of electricity consumption; and computing the number of preestablished units obtained to provide a value proportional to chargeable electricity consumption. The adjustment to the integration is carried out in accordance with four bands of network voltage, in the form of a nominal band on either side of the nominal network voltage, an overvoltage band, an extended voltage band below the nominal band, and an undervoltage band.

Abstract: Line voltage and line current signals are sensed on a power line having at least one conducting path. The sensed line voltages and line currents are converted into a digital signal. A phase-to-neutral voltage signal and phase current signal are computed from the digital signal to thereby define a phase of the power line. An interval of orthogonality is determined from the sensed voltage and current signals, coinciding with passage of an integral number of cycles of a fundamental frequency reference signal which is computed from the computed phase-to-neutral voltage signal. A vector metering quantity is computed for the determined interval of orthogonality from the computed phase-to-neutral voltage signal and the computed phase current signal. The vector metering quantities to be computed may be identified and computed based upon an associated detent. The vector metering quantity is also computed based on an identified circuit topology.

Abstract: In the precision source disclosed herein, a reference waveform and a correction waveform are combined and fed to an output amplifier which supplies an output waveform to a load, e.g., a wattmeter under test. The reference and correction waveforms are generated by digital-to-analog conversion of values stored in respective data tables. The output waveform is then combined with the reference waveform to obtain an error signal which is then digitized and utilized to update the data table from which the correction waveform is generated.

Abstract: An electricity meter and method for measuring VA power consumption. The electricity meter comprises a transducer circuit receiving line current and line voltage and producing a first signal corresponding to active power on the line, and a level shifting circuit responsive to the first signal for producing a second signal corresponding to apparent power.

Abstract: The current invention is directed to a method of measuring an electric power and in particular to a precise power measurement by measuring a current and a voltage of high-frequency distortion waves. The current power measuring method is based upon a summation of the power values measured for every frequency component of the distortion wave. After being frequency converted in a mixer 5, a voltage is inputted from an input terminal 1 through a voltage amplifier 3 to a vector voltmeter 7. A current is supplied into an input terminal 2, and converted into a voltage signal by a current-to-voltage converter 4. Then, the voltage signal is frequency-converted in a mixer 6, and thereafter inputted into a vector voltmeter 8. The input signals to the mixers 5 and 6 are separated into frequency components by sweeping of a local signal generator 10, which are measured by the vector voltmeters.

Abstract: A power calculating device including a control signal generating unit for generating a control signal. The control signal determines a power calculating period and an imbalance compensation period. The device also includes an input voltage changeover unit for changing over between a first voltage corresponding to a voltage of a system under measurement and a constant voltage under the control of the control signal to generate a second voltage, which is the first voltage during the power calculating period and the constant voltage during the imbalance compensation period. The device further includes a Hall element member for generating a third voltage corresponding to a product of the second voltage and a magnetic density generated by a magnetic field applied to the Hall element member. The device also includes an imbalance detecting unit for generating an offset compensation signal based on the third voltage, and a variable resistor connected to the Hall element member.

Abstract: A first Hall element is supplied with a current proportional to a load voltage and applied with a magnetic field proportional to a load current and produces a voltage proportional to a load power given by the load voltage and the load current. A second Hall element has the same characteristic as that of the first Hall element and supplied with the current proportional to the load voltage and no magnetic field. The output voltages of the first and the second Hall elements are combined by combining means to compensate and remove an offset voltage component contained in the output voltage of the first Hall element.

Abstract: A method for generating a product of signals proportional to the voltage of an electrical supply and the current flowing through a load connected thereto, comprises the steps of deriving a first signal proportional to the said supply voltage, deriving a second signal proportional to the load current, frequency modulating two constant frequency carrier signals by the said first and second signals to produce third and fourth signals respectively, normalizing the third and fourth signals with reference to frequencies corresponding to zero voltage and zero current, and multiplying the two normalized third and fourth signals to form a product signal which is proportional to the power being absorbed by the load connected to the electrical supply. The third and fourth signals comprise pulse trains whose instantaneous pulse repetition rate is proportional to the voltage and current. Apparatus is described for performing this method. A 555 timer device is employed for voltage to frequency conversation.

Abstract: A circuit has two multiplier modules. Each multiplier module has at least one controllable potentiometer for adjusting the amplitude ratio between an output signal and an input signal of the module. The potentiometers have substantially identical characteristics and they are controlled in the same manner such that the amplitude ratios of the multiplier modules are substantially equal. One of the modules receives as its input signal the first signal to be multiplied and delivers an output signal that is proportional to the product of the two operands, while the other module receives as its input signal a reference voltage and as its output signal it delivers a feedback signal which is servo-controlled to a value that is approximately equal to the value of the second signal to be multiplied. The circuit is applicable to meters for electrical energy.

Abstract: An electric power detector for a three-phase AC voltage supply which measures the current of one phase and the voltage between the one phase and another phase and computes the phase difference between the voltage and the current, decides the phase rotation direction by comparing the phase difference with a specified angle, and obtains a power factor angle by adding or subtracting 30.degree. to or from the phase difference corresponding to the result of the decision to produce a power factor angle for computing three-phase power.

Abstract: The monitoring and control system of the present invention provides a distributed intelligence, data acquisition and control system which collects and analyzes large amounts of data representing power usage from a power distribution substation. Using a Discrete Fourier Transform, the system provides accurate tracking of the primary frequency of the voltage and current waveforms in the power equipment, and determines the relative phase between the voltage and current waveforms. The system provides real time monitoring of power usage and real time control of various functions in the substation.

Abstract: An apparatus and method for measuring electrical energy and quadergy and for performing line frequency compensation includes a compensation integrated circuit for adjusting the determined reactive load quadergy, based on variations between the actual line frequency and the rated line frequency of the meter. Reactive load quadergy is determined by phase-shifting the line voltage by a fixed time interval, based on the rated line frequency of the meter. The determined reactive load quadergy is adjusted to compensate for variations in line frequency. Because the determined reactive load quadergy is output by an electric meter as a continuous pulse train, adjustment to the determined reactive load quadergy is performed by adding or subtracting state changes from the pulse train and then registering the adjusted reactive load quadergy.

Abstract: A circuit is disclosed for measuring reactive energy or reactive power. The circuit comprises a main multiplier, a signal/frequency converter, and a frequency divider all connected in series to form a cascade circuit having an output connected to a display. A 90.degree. phase shifter has an input for receiving a first signal component (e.g., alternating voltage) of the reactive energy or power. A second signal component (e.g., alternating current) is connected to a second input of the main multiplier. The phase shifter has a frequency dependent transfer function K[f]. In order to eliminate the effect of this transfer function on the measurement of reactive power or reactive energy, the arrangement includes a frequency measurement circuit for measuring the frequency of the first signal component and a frequency/signal converter for generating an output signal dependent on K[f].

Abstract: A method of operating a meter to perform the steps of generating a measure of real energy consumed, generating a measure of reactive energy consumed, and generating, from the real energy and reactive energy measures, a measure of apparent energy consumed. In one embodiment, the real energy and reactive energy measures are provided as integer quantity inputs. Particularly, assume S=kVAh, P=kWh, Q=kVARh, and R=Residue. Respective registers store values of P, [2P+1], Q, [2Q+1], and the sum [P.sup.2 +Q.sup.2 ]. Initially, the P, Q, and [P.sup.2 +Q.sup.2 ] registers are set to zero, while the [2P+1] and [2Q+1] registers are initialized to 1. At the arrival of a P pulse, the value in the [2P +1] register is added to the [P.sup.2 +Q.sup.2 ] register, then the P register is incremented by 1 and the [2P+1] register is incremented by 2. Exactly the same steps are carried out subsequent to receipt of a Q pulse.

Abstract: An electric power measuring system wherein power factor measurements are adjusted to reflect the adverse economic effects of harmonic currents and voltages. Well-known techniques are used to acquire frequency spectra that represent the voltages and currents present at the measuring point. These spectra are weighted in such a way that non-fundamental currents are increased and non-fundamental voltages are decreased. The weighted spectra are used to calculate a harmonic-adjusted volt-ampere measurement, which is then accumulated to form a harmonic-adjusted volt-ampere-hour measurement. The weighting functions for voltage and current are selected to approximate the economic impact on the AC power generating, transmission, and distribution system of non-fundamental currents and voltages. The resulting harmonic-adjusted volt-ampere-hour measurement is used to calculate a harmonic-adjusted power factor measurement.

Abstract: In a reactive volt-ampere-hour meter, either of a pair of electric signals representative of, respectively, an AC voltage and an AC current fed to a load has the phase thereof shifted by 90 degrees to produce a signal representation of a product of the two signals. A cumulative adder cumulates the resulting product signals. A first carry pulse and a borrow pulse are generated in the event of, respectively, an overflow and an underflow during cumulation and are fed to a first and a second up-down counter, respectively. The first up-down counter up-counts the first carry pulses and down-counts the borrow pulses and generates a second carry pulse when an overflow occurs. The second up-down counter up-counts the borrow pulses and down-counts the first carry pulses and generates a third carry pulse in the event of an overflow. An up-counter up-counts the second and third carry pulses from the first and second up-down counters, respectively.

Abstract: Separate pulse inputs from respective metering circuits, representing the reactive R and in-phase W power components, are converted to a pulse output V representing the vector sum of those components. The two inputs are applied to increment respective registers, the output V is held in a third register, and a fourth register is provided to store the REMAINDER value (W.sup.2 +R.sup.2)-(V+1).sup.2. The meter includes a processor for incrementing the REMAINDER value by 2W+1 for each increment of W and 2R+1 for each increment of R and for incrementing V whenever the REMAINDER value is zero or positive and at the same time reducing the REMAINDER value by 2V.sub.1 +1, where V.sub.1 is the incremented value of V. The FRACTIONAL error in the value of V is determined by means of a look-up table.

Abstract: A method and apparatus for measuring AC power, in which a measured digital value of an AC voltage is decomposed into two components with a phase difference of 90.degree. therebetween, while a measured digital value of an AC current is decomposed into two components with a phase difference of 90.degree. therebetween, and a scalar product of a first vector consisting of the two components of the AC voltage and a second vector consisting of the two components of the AC current is calculated. The scalar product thus calculated represents active power carried by the AC current at the AC voltage. Separately, absolute value of vector product of the first vector and the second vector may be calculated, which absolute value of the vector product represents reactive power carried by the AC current at the AC voltage.

Abstract: A phase detector includes a pulse amplitude modulator and an integrator. The pulse amplitude modulator comprises a change-over switch the control input of which is fed by pulses which are subjected to mark/space modulation by means of a phase-shifted signal while the amplitude input of the pulse amplitude modulator is fed by a non-phase-shifted signal. The integrator includes an integrating amplifier, the output of which is connected by means of a capacitor to an inverting input of the integrating amplifier while the non-inverting input of the integrating amplifier is connected to ground by way of a further capacitor. The inverting and non-inverting inputs of the integrating amplifier are connected by way of respective resistors to two inputs of the integrator which in turn are connected to ground by way of respective resistors on the one hand and which on the other hand are connected by way of respective switch contacts of the change-over switch to the amplitude input of the pulse amplitude modulator.

Abstract: An electronic watthour meter is digitally configurable to operate as several different types of watthour meters for metering electrical energy from a variety of different electric utility services. Automatic scaling of line input currents is provided to scale the voltage input to an analog to digital converter over selected ranges such that low level and high level input signals are measured in an optimum range. A digital signal processor is employed to calculate values for metered electrical energy and output pulses, each proportional to a quantum of energy flowing in the circuit being metered. The processor calculates the value of DC offset errors inherent in the various analog circuits of the meter and uses that value in the calculation of metered electrical energy to compensate for such offset errors. The meter employs automatic and manually initiated test functions for testing the operation of the processor and other critical circuits in the meter.

Abstract: The invention relates to an input circuit for an electrical energy meter, which circuit has a current path and a voltage path, the current path being associated with a mutual conductance transformer. In order to compensate for the differentiating function of the transformer, but without introduicng interference signals, the current path includes an active filter connected as an integrator and provided with a coupling capacitance suitable for blocking low frequency signals.

Abstract: An electronic watthour meter for metering the consumption of electrical energy on power lines includes phase compensation means for compensating for leading and lagging phase differences between line current and voltage, whereby sampling times of the current and voltage are shifted to compensate for phase errors between the current and voltage by controlling timing signals provided to current and voltage analog to digital converters. Digital output signals from the analog to digital converters proportional to current and voltage are multiplied to provide an accurate representation of energy consumption as a result of the compensation.

Abstract: An electric power measuring system wherein the current and voltage components are converted to respective digital signals which are multiplied and integrated to obtain a measurement of total power consumed. The current signal is developed by an A-to-D converter of the successive-approximation type, but differing from conventional such converters in employing two (or more) DACs in the feedback path where the analog feedback signal is developed for comparison with the analog current measurement signal. The two DACs are interconnected in such a way that the feedback signal is proportional to the square of the digital signal produced by the successive-approximation register (SAR). The final digital signal is developed by squaring the digital output of the SAR. The result is increased resolution at the low-level end of the scale, making it possible (in the particular embodiment) to achieve 1% accuracy at 1% of full scale, as well as 1% accuracy at 100% of full scale.

Abstract: An instrument to determine, under actual field conditions, which type of VA demand meters are most appropriate for a particular consumer. The type of electrical load that the consumer places on an electrical supply system can introduce harmonics and phase distortion in the system resulting in VA meters producing incorrect readings. These VA meters are intended to measure the true apparent power S which is defined as S=V.sub.rms XI.sub.rms but, are generally designed to operate according to one of the following approximate formula:(1) S'=V.sub.rect XI.sub.rect X(1.11).sup.2 and(2) S"=.sqroot.P.sup.2 +Q.sup.2 where P is the active power and Q the reactive power.The instrument contains circuit to measure the rms values of the voltage and current waveforms from which the true apparent power S can be obtained as well as circuits to determine the value S' and S" according to the two approximate formula from which error signals e.sub.1 and e.sub.

Abstract: Apparatus for monitoring and displaying energy consumption which comprises at least one communications channel, at least one group of remote stations each comprising a plurality of information channels and connected to a respective communication channel, and a central station connected to the communication channels and capable of addressing the information channels at the remote stations. The central station addresses an energy consumption sensor connected to an information channel at a remote station, and receives energy consumption data from the sensor, computes an energy consumption, and sends a signal representative of the computed energy consumption to a display device connected to an information channel of a remote station to display the same.

Abstract: A multiplier having pulse width modulators for modulating input signals into pulse signals whose pulse widths are corresponding to the levels of the input signals and which are asynchronous to each other; an oscillator for outputting a pulse signal at a frequency higher than any one of those of the pulse signals from the pulse width modulators; a logical gate portion which receives the pulse signals from the pulse width modulators as well as the pulse signal from the oscillator to executes predetermined logical operation on the pulse signals; and a subtracter which calculates, according to the pulse widths of the pulse signals from the pulse width modulators, the number of pulses outputted within a predetermined interval from the oscillator to provide a signal proportional to the product of levels of the input signals.

Abstract: Method and apparatus for metering polyphase power sources in which cycles for each phase are sampled at each degree and converted to a binary representation of amplitude. Sampling commences with a zero cross-over and a first digital conversion provides range data for developing scaling factors which are retained in memory and for providing a selective gain for amplifying. The scaling factor and the range data then are multipled to develop a digital representation of the sample amplitude which may have as many as 21 significant bits plus a sign bit. These expanded data valuations for current and voltage then are selectively multiplied for each degree sampled to develop data available for generation of 12 electrical parameter outputs. Generally, six of these outputs will be elected by the user. Volt amperes are computed with respect to the zero cross-over events for both voltage and current samples, while quantities such as Q and var are developed by selective delayed multiplication of the unit degree samples.

Abstract: The measuring circuit comprises an integrator to which a signal representative of the current flowing through the primary winding of the output transformer of an inverter is applied. The integrator output signal is reset at the beginning of each period of the A.C. component of said current and is applied to a sample and hold stage whose output signal represents the integrator output signal just before it is reset. An intermediate stage is arranged between the integrator and the sample and hold stage to reduce the influence of load impacts by limiting the maximum possible variation of the output signal during the sampling period.

Abstract: A method and circuit arrangement for measuring in-phase current and quadrature current in an electrical alternating current power supply is disclosed. The invention uses a microprocessor whereby four integral values A.sub.1 through A.sub.4 are combined in such as to allow determination of the in-phase current and the quadrature current. The invention is useful in recording in-phase and quadrature components of current from an alternating current power supply.

Abstract: The method and apparatus disclosed relates to the electronic measurement of the electricity used by a load. The apparatus generates a rectified voltage signal proportional to the load voltage. A frequency modulated pulse train is generated in response to the load voltage signal, with the frequency of the pulses being proportional to the instantaneous amplitude of the rectified load voltage. A load current signal is generated that is proportional to the load current. A logic circuit gates the load current signal during each pulse of the frequency modulated pulse train to generate a signal representing the product of the instantaneous load voltage and the instantaneous load current. This signal from the logic means may be integrated over time to generate a signal representing the amount of electric energy used by the load. A method for practicing this invention is also disclosed.

Abstract: An electricity metering transducer is disclosed which samples voltages and currents at an innerconnection terminal of an electrical energy distribution system, converts those samples to digital form and computes selected electricity metering quantities. In a multiphase system current and voltage signals are multiplexed to a pair of codecs, one for current signals and one for voltage signals. The period of the signals being sampled is detected and used to generate a substantially nonsynchronous sampling signal so that a sample migration system is created which provides a large number of samples of a composite wave form. The steps of a digitally generated stepwise approximation of a sawtooth waveform are summed with the sequential analog samples and then removed from the digital value of each sample by software operation in order to increase the resolution of the digital to analog conversion.