Current transducers are widely used in current measuring systems. They provide good isolation between the supply voltage and the measurement equipment. However they can introduce small phase errors which can become significant sources of error if the current to a load is out of phase with the supply voltage for the load. This disclosure discusses a robust measurement apparatus and method that can be used in situ to monitor for and correct phase errors.

A measurement system for an electrical installation includes at least one voltage measurement module and at least one current measurement module , which are coupled to the electrical installation, each measurement module including a sensor, a processor, a memory and a clock. A method for determining an electrical quantity in the installation allows the current measurement module to determine, for each synchronization signal received from the voltage measurement module, successive delay correction values on the basis of a main timestamp datum received from the voltage measurement module and a locally calculated timestamp datum. The successive current measurements taken by the current measurement module are timestamped by the module using the clock thereof, taking into account the delay correction values thus determined.

The invention relates to a method and a system for measuring imbalances in an electrical grid. The method comprises the steps of obtaining effective values and arguments of the phase voltages and currents at the fundamental frequency; calculating the effective value and the argument of the positive sequence voltages and the effective values of the negative sequence voltages; determining the active and reactive powers of each of the phases at the fundamental frequency; and calculating the value of the imbalance power vector according to the following equation:

[00001]${\stackrel{\_}{S}}_u=V_{+}.Math.\sqrt{2+2.Math..Math.{\delta }_u^2+2.Math..Math.{\delta }_A^2}.Math.(.Math.\begin{array}{c}\begin{array}{c}\frac{P_{A.Math..Math.1}}{V_{A.Math..Math.1}}.Math.\cos .Math..Math.\left({\alpha }_{+}-{\alpha }_{A.Math..Math.1}\right)+j.Math.\frac{{\stackrel{\_}{Q}}_{A.Math..Math.1}}{V_{A.Math..Math.1}}.Math.\sin .Math..Math.\left({\alpha }_{+}-{\alpha }_1\right)+\end{array}\end{array}$

The invention relates to a method and a system for measuring imbalances in an electrical grid. The method comprises the steps of obtaining effective values and arguments of the phase voltages and currents at the fundamental frequency; calculating the effective value and the argument of the positive sequence voltages and the effective values of the negative sequence voltages; determining the active and reactive powers of each of the phases at the fundamental frequency; and calculating the value of the imbalance power vector according to the following equation:

[00001]${\stackrel{\_}{S}}_u=V_{+}.Math.\sqrt{2+2.Math..Math.{\delta }_u^2+2.Math..Math.{\delta }_A^2}.Math.(.Math.\begin{array}{c}\begin{array}{c}\frac{P_{A.Math..Math.1}}{V_{A.Math..Math.1}}.Math.\cos .Math..Math.\left({\alpha }_{+}-{\alpha }_{A.Math..Math.1}\right)+j.Math.\frac{{\stackrel{\_}{Q}}_{A.Math..Math.1}}{V_{A.Math..Math.1}}.Math.\sin .Math..Math.\left({\alpha }_{+}-{\alpha }_1\right)+\end{array}\end{array}$

A power meter includes a plurality of first terminals for receiving a measure of current and a plurality of second terminals for receiving a measure of voltage of each of one or more phases of power that is delivered to the load. A controller is configured to determine a number of power monitor parameters based on the measure of current of each of one or more phases of power that is delivered to the load and/or the measure of voltage of each of one or more phases of power that is delivered to the load. The power meter includes an I/O interface for communicating one or more of the power monitor parameters over a network using a configurable mapping that maps the power monitor parameters with corresponding addressable locations.

A power meter includes a plurality of first terminals for receiving a measure of current and a plurality of second terminals for receiving a measure of voltage of each of one or more phases of power that is delivered to the load. A controller is configured to determine a number of power monitor parameters based on the measure of current of each of one or more phases of power that is delivered to the load and/or the measure of voltage of each of one or more phases of power that is delivered to the load. The power meter includes an I/O interface for communicating one or more of the power monitor parameters over a network using a configurable mapping that maps the power monitor parameters with corresponding addressable locations.

Systems and methods provide power quality devices that have a dual use connector that will couple to a device being protected, such as a telephone handset, and will also provide a communication interface that a technician can access to establish communications with the power quality device.

A system for managing electrical loads includes a plurality of branch circuits, a sensor system, and control circuitry. The sensor system is configured to measure one or more electrical parameters corresponding to the plurality of branch circuits, and transmit one or more signals to the control circuitry. The control circuitry is configured to determine respective electrical load information in each branch circuit based on the sensor system, and control the electrical load in each branch circuit using controllable elements based on the respective electrical load information. The control circuitry transmits usage information, generates displays indicative of usage information, accesses stored or referencing information to forecast electrical load, and manages electrical load in response to identified events. The control circuitry can associate each branch circuit with reference load information, and disaggregate loads on each branch circuit based on the reference load information and on the electrical load in the branch circuit.

A system for managing electrical loads includes a plurality of branch circuits, a sensor system, and control circuitry. The sensor system is configured to measure one or more electrical parameters corresponding to the plurality of branch circuits, and transmit one or more signals to the control circuitry. The control circuitry is configured to determine respective electrical load information in each branch circuit based on the sensor system, and control the electrical load in each branch circuit using controllable elements based on the respective electrical load information. The control circuitry transmits usage information, generates displays indicative of usage information, accesses stored or referencing information to forecast electrical load, and manages electrical load in response to identified events. The control circuitry can associate each branch circuit with reference load information, and disaggregate loads on each branch circuit based on the reference load information and on the electrical load in the branch circuit.

This application discloses an alternating-current energy detection apparatus, in which a voltage detection unit forms a coupling capacitance together with a tested cable, obtains a first voltage based on an actual voltage and the coupling capacitance, and outputs the first voltage to a data processing unit; a current detection unit detects a tested-cable current, and outputs the tested-cable current to the data processing unit; and the data processing unit receives the first voltage and the tested-cable current, and determines a first voltage value and a tested-cable current value; calculates a product of the first voltage value and a quantity of amplification times of a tested-cable voltage, and determines a tested-cable voltage value; and calculates, based on the tested-cable voltage value and the tested-cable current value, electric energy transmitted by the tested cable.