Abstract: An electronic wattmeter monitors the current and voltage of power lines and generates unitized voltage pulses at a frequency that is proportional to the average power carried by the lines. The wattmeter includes a current transducer that is inductively coupled to the monitored power lines. The transducer generates an induced current that is representative of the current that flows in the lines. The current transducer includes a magnetically permeable frame which has two magnetically permeable, spaced parallel leg members and a magnetically permeable cross-member that is detachably affixed between the leg members. The monitored power lines pass through an aperture defined by the leg members and cross-member of the frame and the frame additively applies the magnetic fields of the conductors to a coil that is inductively coupled to the frame. The coil generates an induced current corresponding to the current of the conductors.

Abstract: In a metal-clad, compressed gas-insulated high-voltage switching installation, installation parts can be cut off by a circuitbreaker and connected to the grounded casing by means of a grounding switch, insulated measuring electrodes connectable to the testing terminal of a capacitive voltage divider and to a display device being provided in the casing adjacent to the grounding switch, for observation of the conductor voltage.To obtain a simple test setup in a three-phase clad installation, two pin-type measuring electrodes are arranged respectively centrally between pairs of the three conductors in such a way that their rounded end protrudes into the interior of the casing.

Abstract: An electric energy meter includes a mutual inductance current transducer formed by primary winding means for direct connection to the current component of an electric energy quantity to be measured. Secondary winding means is inductively coupled to the primary winding means to produce an analog signal that is proportional to the time derivative of the current component. The current responsive analog signal and a voltage responsive analog signal are both applied to an electronic watthour measuring circuit.

Abstract: A device for measuring a quantity such as the electric power in a polyphase alternating current network including at least two phase conductors and a reference conductor, of the type comprising two measuring devices which are associated respectively with the two phases and the outputs from which are connected to a summation device.A supply circuit connected to one of the phases is associated with the corresponding measuring device, and a device connected to the other phase ensures the supply to the other measuring device and to the summation device, the supply circuit and the supply device being connected through a high-impedance tie circuit, the summation device being supplied if at least one of the phases is under voltage with respect to the reference conductor.

Abstract: A fault detector for an electrical transmission system and a remote current sensor for use therein. The remote current sensor includes a Hall effect transducer for measuring the magnetic field surrounding a conductor of the transmission system to thereby monitor the current flowing through the conductor. The transducer is positioned between a pair of tapered pole pieces for concentrating low density magnetic flux in the air into a high density magnetic flux focused onto the transducer. The pole pieces enable the sensor to be positioned a distance from the conductor which is greater than the electrical arcing distance so as to allow use of the air gap between the conductor and sensor as insulation. For a triangular configuration of conductors, two remote current sensors having orthogonal sensitive axes are positioned at a location equidistant from all three conductors.

Abstract: An electronic multiphase watt-hour metering system containing time-division multiplying circuitry. A duty cycle modulator and a switching device are provided for each phase of interest, the output signals of which are combined and conducted to a current-to-frequency converter. The output frequency of the current-to-frequency converter is responsive to the rate of electrical power consumption from a multiphase transmission system. In one embodiment, the current-to-frequency converter is coupled at its output to an accumulating counting system for recording the total energy supplied to a load. There may further be provided an indicator responsive to the frequency of the current-to-frequency converter for providing a visual indication of the instantaneous rate of power usage.

Abstract: A monitor for a polyphase power line continuously compares the voltage on each phase of the power line with reference voltages that are selected percentages above and below the average of the power line voltages to detect voltage unbalance and with fixed voltages to detect high or low voltage conditions. The monitor is also responsive to phase sequence.

Abstract: An electronic watthour meter comprising: a pulse width modulation circuit for subjecting a voltage signal, proportional to the load voltage of a power supply line, to pulse width modulation to obtain a pulse width duty cycle signal; a multiplication circuit in which a plurality of analog switches are selectively operated, with the aid of the pulse width duty cycle signal, so that positive and negative DC voltages equal in absolute value are obtained from the product of a voltage signal, proportional to the consumption current of the power supply line, and the pulse width duty cycle signal attributing to the voltage signal proportional to the load voltage; and a dual-slope type frequency conversion circuit for converting the positive and negative DC voltages into a frequency signal.

Abstract: A technique for detecting high impedance faults on solidly grounded, wye connected distribution circuits is disclosed herein. This technique bases its detection on the status of the third harmonic current component in each three-phase line current of the distribution circuit and specifically by the change in the phase of any one of the components during a period when the phases of the other third harmonic components remain unchanged. AT the same time, the technique disclosed herein discriminates between high impedance faults and many of the normal system disturbances such as capacitor switching, line switching, fuse blowing and others.

Abstract: In a polyphase electric energy meter, voltages of the phases of a polyphase alternating power to be measured are utilized to subject an input pulse signal to be applied to a pulse distributor to pulse width modulation to form polyphase control pulses, which cyclically operate switches provided respectively for the phases so that an operation circuit cyclically receives the voltages and currents of the phases and produces a current output proportional to the sum of the electric powers of the phases.

Abstract: In apparatus for indirectly measuring the output DC current of a rectifier device on the input side of a polyphase rectifier transformer, a polyphase auxiliary current transformer is provided and the polyphase primary or secondary windings thereof are combined such that the area of the decreasing secondary current waveform is made equal to the area of the increasing secondary current waveform during commutation thereby releaving the secondary current from the adverse effect of the overlap angle.

Abstract: Disclosed is an apparatus and method for determining effective power and apparent power by multiplying voltage and current samples and algebraically summing the sample products to obtain effective power and level shifting the product signals to the level of the lower peaks of the envelope curve of the product signals which are proportional to the return power and algebraically summing the sample products to obtain apparent power.

Abstract: A current measuring apparatus for polyphase current wherein reverse poled parallel diodes in each of the polyphase lines provide separate direct current paths for the alternate half cycles of the polyphase current. Alternate half cycles having like polarity of each phase are summed using the magnetic field created by the current components and a Hall-effect device.

Abstract: A dc measuring circuit for power rectifiers is described wherein primary line current is utilized to measure direct current output. In the measuring circuit, line current transformers are connected to a multiphase instrument rectifier through a phase shifting current transformer which is adjustable to compensate for differences between the primary and secondary line current phase shift characteristics of the power transformer and any phase shift in the line current transformer. By such compensation, the average value of rectified primary line current in the measuring circuit is maintained independent of the commutating angle of the rectified power current. The dc measuring circuit includes means for providing unity current transformation through the phase shifting current transformer. The dc measuring circuit also includes means for handling the presence of zero sequence current without causing measurement error or circuit damage.

Abstract: In an alternating current electric power system of the type subject to rapid load voltage regulation as a result of variations in reactive load current, reactive load current compensation is provided by fixed capacitors and inductors in parallel with the load, the inductors being in series with static switches which are phase controlled to continuously maintain the net reactive compensating current substantially equal and opposite to the reactive component of load current. Compensation control determines firing time of static switches in accordance with the magnitude of reactive load current. The compensation control includes means rapidly responsive to rapid current disturbances. In one embodiment, the compensation control includes devices for continuously sensing the phase and magnitude of the reactive load current. In another embodiment, the compensation control includes devices for sensing the phase and magnitude of the reactive load current 12 times per cycle of source frequency.

Abstract: An in-line voltage balancing circuit sums a trim voltage with each phase voltage of a polyphase generating system to assure that the voltage between each phase and neutral is equal to the average voltage of all the phases. An individual error signal representative of the difference between each phase voltage and the average voltage is provided to individual phase modulator circuits. The phase modulator circuits develop pulse width modulated signals wherein the pulse width is proportional to the amplitude of the error signal. The outputs of the phase modulator circuits are connected to switching amplifiers which provide trim voltages proportional to the phase modulated signals. Summing transformers are employed to sum the individual trim voltage with appropriate phase voltage so that the voltage for each phase equals the average voltage.

Abstract: Disclosed is combination surge voltage protective and test apparatus for an AC supply system, the apparatus including a plurality of surge voltage protectors switchably connected with the supply lines and an interconnected test network operable to test the status of the supply voltages when the switch is closed and to test the status of the surge voltage protectors when the switch is open. The apparatus is disposed with an enclosure having a door which, when closed, closes the switch and prevents application of power to the test network, while otherwise allowing access to operation of the test network.

Abstract: In an alternating current electric power system of the type subject to rapid load voltage regulation as a result of variations in reactive load current, reactive load current compensation is provided by fixed capacitors and inductors in parallel with the load, the inductors being in series with static switches which are phase controlled to continuously maintain the net reactive compensating current substantially equal and opposite to the reactive component of load current. Compensation control determines firing time of the static switches in accordance with the magnitude of reactive load current. Regulating means additionally controls firing time to maintain line current and line to neutral voltage at a selected line location substantially in phase coincidence. The regulating means is provided with means for enhancing the stability of the system under no load or light load conditions.

Abstract: An electronic three-phase four-wire system watt-hour meter equipped with a single operational circuit which multiplies the voltage and the current of each phase of a three-phase alternating current power source of which electric energy is to be measured. Electronic switches are provided which work on voltage and electronic switches are provided which work on current in each phase. Said electronic switches are cyclically opened and closed by three-phase pulse signals provided for control. The operational circuit produces, in the form of a current, an output corresponding to the sum of the electric power of each phase of said three-phase alternating current source.

Abstract: Three-phase power equipment while still connected to the three-phase line has the insulation qualities of its various phases tested. All ground connections of said equipment except one are disconnected and that one is reconnected through ground current sensing means. Coupling units which may be capacitors are respectively connected between each of the three phases of the power line to which the power equipment is connected and ground. Each coupler unit is a reference phase current sensing means. Adjustable phase and magnitude adjustor means are used to couple the respective phase current sensing means to a summing means so that they are adding. The ground current sensing means is similarly coupled to the same summing means but opposed to phase current effects. A null detector coupled to the summing unit detects when balance occurs.

Abstract: For measuring and indicating phase voltage, phase sequence and other electrical values in a three-phase power system, and electrical values in single-phase and DC systems, a unitary instrument or apparatus includes a meter movement and three phase-resistors of equal value which are connected to a common juncture defining a neutral point, with a first phase-resistor connected in series with the meter. The three phases of the external circuit to be tested are connected respectively to the three phase-resistors through a three-pole three-position selector switch for selecting the three different phase to "phase-resistor" relationships. A switch connected between a third phase-resistor and the common juncture performs the alternative functions of opening or closing this circuit.

Abstract: In an alternating current electric power system subject to rapid load voltage regulation as a result of variations in reactive load current, reactive load current compensation is provided by fixed capacitors and inductors in parallel with the load, the inductors being in series with static switches which are phase controlled to continuously maintain the net reactive compensating current substantially equal and opposite to the reactive component of load current. Compensation control determines firing time of the static switches in accordance with the magnitude of reactive load current and regulating means additionally controls firing time to maintain line current and voltage at a selected line location substantially in phase coincidence.

Abstract: In the exemplary embodiment, a double-pole double-throw-C-MOS analog switch provides output signals alternately 180.degree. and 0.degree. with respect to the output of a single secondary winding on a current transformer, which single secondary winding is resistance terminated. The switch control signal is pulse-width modulated in proportion to the line voltage thus making the D.C. component of the net output from the analog switch proportional to the instantaneous product of line voltage and line current or power consumption. This power consumption signal is then conventionally processed to provide data indicating the total accumulated energy consumption in the monitored circuit.

Abstract: A DC measuring circuit for power rectifiers is described wherein primary line current is utilized to measure direct current output. In the measuring circuit line current transformers are connected to a multiphase instrument rectifier through a phase shifting current transformer which is adjustable to compensate for difference between the primary to secondary line current phase shift characteristic of the power transformer and any phase shift in the line current transformers. By such compensation the average value of rectified primary line current in the measuring circuit is maintained independent of the commutating angle of the rectified power current.