A revenue accuracy meter and a method are provided for measuring the amount and quality of power received by a power customer across electrical power lines. The revenue accuracy meter preferably has a variation determiner for determining undesired variations in an electrical signal representative of power received by the power customer during a plurality of predetermined time periods. A power usage measurer is coupled in electrical communication with the variation determiner for measuring the power usage of a customer responsive to an electrical signal representative of a customer load. The meter further has a communications interface coupled in electrical communication with the variation determiner and the power usage measurer for communication signals representative of the power variations and the power usage. An energy management controller also preferably is connected to the communications interface for controlling power usage responsive to predetermined electrical command signals received from the power customer through the communications interface.

Electrical energy meters having real-time power quality measurement and reporting capability

A method and apparatus for rapidly and continuously sampling AC voltage and current signals in a plurality of power distribution circuits. The sampled signals are then analyzed in a sine board computer to derive the number of fundamental electrical variables. These variables include frequency, RMS volts, RMS amps and a phase angular relationship between the voltage and currents in the system. The computer also performs calibration and compensation functions. From these fundamental variables, other useful parameters can be calculated such as watts, watt-hours, VARS, and power factor.

High speed power analyzer

An apparatus for electronically communicating metered electrical power is disclosed. A first processor receives voltage and current signals and determines electrical power. The first processor generates an power signal representative of the electrical power determination. A second processor, connected to said first processor, receives the power signal and generates an output signal representative of electrical power information. A output device is connected to receive the output signal to output the electrical power information. The first processor determines units of electrical power from the voltage and current signals and to generates an power signal representative of the determination of such units and the rate at which the units are determined. The output devices may be one of a display, optical port and an option connector. When the output device is a display, the second processor may generate a disk signal representative of a rate of disk rotation in relation to the rate at which the units are determined, wherein the output signal to the display is representative of the units, the rate at which said units are determined, and the rate of disk rotation. The first processor, while concurrently determining units of electrical power, further may determine watt units, apparent reactive power units and the rate at which such units are determined, wherein the watt units, the apparent reactive power units and the rate at which such units are determined are displayed. The first processor may also meter multiple types of electrical power and generates power signals. The second processor, when connected to the optical port, generates an output signal in response to the power signals, wherein the generation of the output signal includes the multiplexing of the power signals into the output signal.

Apparatus for metering electrical power and electronically communicating electrical power information

A digital solid state electric power usage meter for determining power usage by a load attached to an electric power network. The meter has a current sensor coupled to each phase of the electric power network for sensing current in each phase, a voltage divider coupled to each phase of the power network for detecting the voltage level on each phase, an analog to digital (A/D) converter coupled to the current sensors and voltage dividers receiving signals from the current sensors related to the current in each phase and signals from the voltage dividers related to the voltage on each phase. The A/D converter samples the current and voltage related signals at predetermined times at a rate which insures that samples of the current and voltage related signals do not repeat for a large number of cycles of the network frequency or never repeat and which rate is at least twice as fast as the rate of change of the current and voltage related signals and converts the samples to digital signals representing the voltage levels and current at the predetermined times. A processor calculates instantaneous values of power at the predetermined times from the digital signals and a memory accumulates the instantaneous values so as to form a value representative of electric power usage by the load attached to the network.

Solid state electric power usage meter and method for determining power usage

A meter device for measuring electrical energy is provided. The meter device includes circuitry for measuring at least one parameter of electrical energy provided to the meter device. A storage device is provided for storing at least one calibration factor for compensating for errors associated with at least one of at least one external current transformer (CT) and at least one external potential transformer (PT) that operates on the electrical energy provided to the meter device. At least one processor is provided for processing the at least one calibration factor for adjusting the measuring for compensating for the errors when measuring the at least one parameter of electrical energy.

System and method for compensating for potential and current transformers in energy meters

Power measuring apparatus including a first multiplexor having its inputs responsive to the polyphase voltage and current inputs being measured. The multiplexor reads these inputs in sequence based on address signals provided by a program controlled microprocessor. The output of the multiplexor is coupled to an RMS to DC converter, the output of which is coupled to a second multiplexor. The voltage inputs are coupled to a voltage averaging device, the output thereof being coupled to additional inputs of the second multiplexor, the output of the second multiplexor being coupled to the microprocessor via an analog to digital converter. The microprocessor reads and compares the voltage output from the averaging circuit and the corresponding voltage at the output of the converter and generates a correction factor and responds thereto. The microprocessor to periodically adjusts the digital value of the voltage from the averaging circuit in response to the correction factor, the adjusted signal being coupled to display means for visual readout. A third multiplexor is provided to detect polyphase voltages and currents. The outputs of the third multiplexor are coupled under the control of the microprocessor to an analog multiplier in a time shared manner via voltage and currents scaling devices such that each phase voltage and corresponding current is simultaneously coupled to the multiplier. The output of the multiplier is coupled to a low pass filter, the output of which corresponds to the kilowatt power consumed for that phase. The microprocessor is capable of calculating a system power factor.

Robert D. Catiller

Papers

Apparatus for providing cost efficient power measurement