84results about "Moving-iron instruments" patented technology

An electric power meter includes an embedded decomposition module that is configured to decompose a power meter signal into constituent loads to segregate and identify energy consumption associated with each individual energy consumption device within a plurality of energy consumption devices coupled to the power meter.

A system, device, and method of detecting an overload condition of a distribution transformer that supplies power to one or more customer premises via a low voltage subnet is provided. In one embodiment, the method comprises determining the power output of the transformer; storing in a memory a threshold power value for the transformer; determining whether the power output exceeds the threshold power value; and, if the output power exceeds the threshold power value, providing a notification. Providing the notification may include wirelessly transmitting the notification and / or transmitting the notification over a medium voltage power line. The low voltage subnet may comprise a low voltage feeder that supplies power to a plurality of low voltage supply lines that extend to the customer premises in which case determining the output power may comprise measuring a voltage of the low voltage feeder and measuring a current traversing the low voltage feeder. The method may also comprise storing in the memory a plurality of threshold power values associated with a plurality of transformers, such as different models of transformers; receiving data of the power output of a multitude of transformers; and determining whether the power output of each of the multitude of transformers exceeds the threshold value associated with the transformer, which steps may be performed at a central computer system such as a power line server.

Disclosed herein are signal identification methods and systems. In some examples, the method and / or system allows appliances to be associated with their electrical usage. In one example, a method for determining whether a load is in a steady state or in transition includes analyzing a time series of electric power or current measurements on at least one circuit, at least one load coupled to the at least one circuit; and determining whether the load is in a steady state or a transition. Also disclosed is an appliance identification method. Further disclosed is a method of mapping unlabeled appliances which utilizes a STEC Table which summarizes linkages between transitions and steady state clusters.

The present invention relates to current measurement apparatus 100. The current measurement apparatus 100 comprises a measurement arrangement 110, 114 which is configured to be disposed in relation to a load 108 which draws a current signal, the measurement arrangement being operative when so disposed to measure the load drawn current signal. The current measurement apparatus 100 also comprises a signal source 112 which is operative to apply a reference input signal to the measurement arrangement 110, 114 whereby an output signal from the measurement arrangement comprises a load output signal corresponding to the load drawn current signal and a reference output signal corresponding to the reference input signal. The current measurement apparatus 100 further comprises processing apparatus 116 which is operative to receive the output signal and to make a determination in dependence on the reference output signal and the load output signal, the determination being in respect of at least one of the load drawn current signal and electrical power consumed by the load.

In a digital branch circuit monitor, compensation for the phase error is accomplished by selecting a voltage sampled at a time temporally offset from the sampling time of the current by an interval quantifying the phase shift of the secondary current relative to the primary current that is characteristic of a current transformer.

A device for measuring alternating voltage in a conductor under test comprises a first set of capacitive voltage sensors 32a-f mounted on an electrically insulating support member. The sensors are disposed on the support member at spaced intervals along a first notional circle and are connected in parallel between an inner signal conductor 33 and a zero voltage reference conductor 37. A second set of capacitive voltage sensors 34a-f are mounted on the support member at spaced intervals along a second notional circle and are connected in parallel between an outer signal conductor 35 and the reference conductor 37. The support member is configured to allow a conductor under test 38 to be introduced into the interior of the device so that the sensors surround the axis of the conductor. Each sensor has a signal electrode 48 connected to the signal conductor and a reference electrode 50 connected to the reference conductor and is orientated with the signal electrode facing the conductor under test. The voltage in the conductor under test is derived as a function of the voltage across the signal conductor and the reference conductor.

A method and system for protecting an electrical power transmission network comprising the steps of: measuring a voltage and a current at a first location in the network other than at a generator in the network; determining positive and negative sequence voltages and currents based on the measured voltage and measured current; determining a negative sequence Thévenin impedance based on the negative sequence measured voltage and negative sequence measured current; defining a positive sequence Thévenin impedance as equal to the negative sequence Thévenin impedance; determining a Thévenin voltage based on the positive sequence measured voltage, positive sequence measured current and the positive sequence Thévenin impedance; determining a load impedance based on the positive sequence measured voltage and positive sequence measured current; and determining the stability of the network using the load impedance and one or more of the Thévenin voltage and positive sequence Thévenin impedance.

A power measuring system, a measuring apparatus, a load terminal, and a device control system are provided, which need no special installation work to be made by any skillful professionals such as persons qualified for electrical work. A voltage sensor detects a voltage waveform of a power line in a noncontact manner, and a current sensor acquires a current waveform of the power line in a noncontact manner. A measuring portion of a load terminal operates a contact means to connect the power line and a voltage measuring terminal to measure a current flowing from the power line to a load and to calculate a voltage value from the measured current value and the load. The measuring portion of the load terminal transmits, in response to a request from a measuring apparatus, the measured current value and the calculated voltage value to the measuring apparatus via a communication means. A control portion of the measuring apparatus receives the current value and the voltage value from the load terminal via a communication means. The control portion calculates a power value based on the received current value and voltage value, as well as on the voltage waveform acquired from the voltage sensor and the current waveform acquired from the current sensor.

Disclosed are apparatus and methodology for coupling plural, spaced-apart printed circuit boards together within a utility meter. An individual, rigid connector is provided that, in concert with conductive edge traces on selected printed circuit boards, provides power and signal coupling alternatives for various printed circuit boards. The connector also provides added physical support for the printed circuit boards.

Current measurement apparatus comprises a measurement arrangement and a signal source. The measurement arrangement is configured to measure a current signal drawn by a load. The signal source is operative to apply a reference input signal to the measurement arrangement whereby an output signal from the measurement arrangement comprises a load output signal corresponding to the load drawn current signal and a reference output signal corresponding to the reference input signal. The signal source comprises a current multiplier which defines first and second current paths and is configured such that: the first path carries a multiplier input current signal; the second path carries a multiplier output current signal which determines the reference input signal and which corresponds to the multiplier input current signal multiplied by a multiplier value determined by the current multiplier; and the multiplier input current signal and the multiplier output current signal are carried on their respective paths in a same direction relative to a power supply voltage. Power drawn through the second path as divided by the multiplier value is less than the power drawn through the first path.

A system and device for measuring voltage in a conductor having a voltage provides a first electrode surrounding and spaced from the conductor, and a second electrode surrounding and spaced from both the conductor and the first electrode such that there is no contact between the conductor and the electrodes or between the first and second electrodes. The first electrode is connected to a first input of a differential amplifier circuit and the second electrode is connected to the other input of the differential amplifier circuit. The output of the differential amplifier circuit provides a voltage signal in proportion to the voltage of the conductor, thus providing a non-contact means for measuring the voltage of a conductor without requiring a connection to ground while simultaneously providing a high level of rejection of external interference.

A device for sensing electrical current or voltage in an electrical distribution system using an actively compensated current ratio transformer that includes a first magnetic core having a first permeability and a second magnetic core having a second permeability higher than the first permeability. A primary winding having P turns is coupled with the first and second magnetic cores, a measurement winding having M turns is coupled with the first and second magnetic cores so that current in the primary winding induces current in the measurement winding, and a sense winding having S turns is coupled with the second magnetic core. An amplifier coupled to the sense winding receives a voltage developed across the sense winding and produces a compensation current in response to the received voltage. The amplifier has an output coupled to the sense winding to feed the compensation current through the sense winding to reduce the voltage developed across the sense winding voltage to substantially zero. A burden resistor is coupled to the measurement winding and the sense winding for receiving the sum of the current induced in the measurement winding and the compensation current.

A current sensor includes coupled inductors that generate an output current responsive to a detected current. The coupled inductor is implemented in an integrated circuited. An integrator circuit generates a sensed voltage responsive to the output current.

A power monitoring system.

Disclosed are apparatus and methodologies for providing improved functionality of a meter in a 2-way communications arrangement, such as an Advanced Metering System (AMS) or Infrastructure (AMI). More particularly, the present technology relates to methodologies and apparatus for providing load side voltage sensing for utility meters which preferably are operable with remote disconnect features in an Advanced Metering Infrastructure (AMI) open operational framework. The present subject matter provides enhanced capabilities resulting in improved functionality, increased safety, and greater economy vis-à-vis fraud detection for individual metrology components in an open operational framework. Meters per the present subject matter utilize a detection circuit, which is situated generally downstream of a remote disconnect functionality. Such detection circuit is able to sense whether voltage exists or doesn't exist at such relatively downstream, or load side location. Providing such functionality allows for: (a) verification that a remote disconnect switch did open subsequent to an instruction or command to do so, (b) identification of possible user fraud, as would possibly be reflected by the presence of voltage at a time when the remote disconnect switch is open, (c) verification that the remote disconnect switch did re-close after having been given an instruction or command to close, and (d) verification of lack of voltage present before re-closing such remote disconnect switch, which serves an important safety feature.

The present invention is to provide a method of voltage measurement and an apparatus for the same having an improved accuracy and low cost. The apparatus for voltage measurement of a voltage supply includes: a charging unit for charging a capacitor for a prescribed period of time of charging; a measuring unit for measuring a charge of the capacitor charged during a prescribed period of time of charge measurement; and a microcomputer for calculating a voltage of the voltage supply from a measurement value of the charge, the microcomputer including: a correction value calculating program for applying a voltage of a correction measurement voltage supply to the measuring unit, measuring the voltage of the correction measurement voltage supply during the prescribed period of time of charging, and calculating a correction value from a difference between a measurement value and a theoretical value of the voltage of the correction measurement voltage supply, and a voltage measurement program for subtracting the correction value calculated at the correction value calculating program from the measurement value of the charge during the prescribed period of time of charge measurement and for calculating the voltage of the voltage supply.

The present invention provides an improved motor current sensor and methods thereof. A first embodiment of the present invention provides a circuit having a signal transfer unit for receiving first and second input signals from opposing terminals of a shunt resistor and a signal conditioner unit for conditioning output signals from the signal transfer unit for a low power control unit. A second embodiment of the present invention provides a circuit having a signal conditioner unit for receiving first and second input signals from opposing terminals of a shunt resistor and delivering output signals to a signal transfer unit and finally to a level shifter for providing first and second voltage signals to a control unit.

A cell voltage measurer of a fuel cell stack and a fuel cell system using the same, the cell voltage measurer including a plurality of terminals electrically connected to a plurality of separators of the stack, respectively; and a plurality of wiring lines coupled to at least one of a plurality of fastening mechanisms and electrically connected to the plurality of terminals, respectively. With this configuration, at least one of the wiring lines is blocked or prevented from being short-circuited by heat generated in the fuel cell stack, and has a sample structure to ease an wiring operation. Since the cell voltage of the fuel cell stack is stably measured to thereby measure (or check) the deterioration of a certain cell (or cell unit), the fuel cell stack is blocked or prevented from being suddenly stopped due to excess deterioration of the certain cell (or cell unit).

An output waveform of a device under test with high output impedance and low load driving capability is faithfully observed. A waveform input circuit 10 comprises a high input impedance terminating resistance which receives an input signal from a transmission line 11, selection means (relay) 12 which selects any one of this terminating resistance and other terminating resistances, and an input buffer 13 which is connected when the high input impedance terminating resistance is selected in the selection means 12, wherein switch means 16 is provided to switch the reference potential of the transmission line 11 to at least two kinds of reference potentials, and one reference potential which is switched by the switch means 16 is “a potential controlled to be in phase with the input signal by an output voltage of the input buffer 13 which is connected when the high input impedance terminating resistance is selected in the selection means 12”.

Provided is a power supply control apparatus including an overcurrent detection circuit with enhanced overcurrent detection accuracy. A power supply control apparatus according to the present invention includes: an output transistor Q1 that controls a current to be supplied to a load; a voltage control circuit that applies a control voltage to a control terminal of the output transistor Q1; and an overcurrent detection circuit. The overcurrent detection circuit includes: a detection MOS transistor Q2 that generates a detection current according to a current flowing through the output MOS transistor Q1; a transistor 9 that generates a current Iref1 based on a bias signal BS1; a transistor 10 that generates a current Iref2 based on a bias signal BS2 that is different from the bias signal BS1, the transistor 10 having a size that is the same as that of transistor 9; and a current mirror circuit that outputs an overcurrent detection signal based on the current Iref1, the current Iref2 and the detection current. Highly-accurate overcurrent detection can be performed by cancelling the effects of the characteristics variations of the transistors in their manufacturing processes and the characteristic variations of the transistors caused by their surrounding temperature conditions.

A power generation system includes a support unit configured to support a power transmission line disposed on a transmission line tower, and a power generation unit. The support unit includes a support line having an end part connected to the power transmission line and a rotary body configured to rotate in a manner cooperating with the support line. The power generation unit is configured to generate electric power in response to rotation of the rotary body caused by movement of the support line resulting from tension of the power transmission line.

A test equipment to test power over Ethernet (PoE) function of an Ethernet device comprises a first connector, a second connector, a data signal transmission circuit, a first polarity determination circuit, a second polarity determination circuit and a notification circuit. The first connector receives and transmits data signals and power signals transmitted by the Ethernet device. The data signal transmission circuit transmits the data signals to the second connector and outputs the power signals. The first and second polarity determination circuits receive and output the power signals to the notification circuit. The notification circuit receives the power signals and consequently generates a notice to indicate the PoE function of the Ethernet device is normal.

An embodiment method of diagnosing a power source arrangement includes a plurality of n power sources connected in series between output terminals, wherein n≧2. At least two different groups of power sources are selected from the power source arrangement. A voltage of each of the at least two different groups is measured between the output terminals. During the measurement of the voltage of one group, the power sources of the power source arrangement that do not belong to the one group are bypassed. The at least two measured voltages obtained through measuring the voltage of each of the at least two different groups or at least two voltages that are dependent on these at least two measured voltages are compared.