Patent ID: 6429785
Filing Date: 2002-08-06
Classification: G01R

Abstract:
An electrical energy meter comprising:a voltage digitizing circuit operable to obtain analog line voltage information and generate digital line voltage information therefrom; a current digitizing circuit operable to obtain analog line current information and generate digital line current information therefrom; a metering circuit operable to receive the digital line voltage information and the digital line current information and generate metering information therefrom; a clock circuit operable to generate calendar/clock information, said clock circuit having a calibration input for receiving precision time calibration information; a source of externally-generated time standard information operably coupled to provide the precision time calibration information to the calibration input of the clock circuit; and a power quality circuit operable to receive the digital line voltage information and obtain magnitude information therefrom, the magnitude information representative of the magnitude of the line voltage, detect a variation in magnitude of the line voltage relative to an acceptable voltage level, wherein the variation exceeds a first variation threshold, obtain calendar/clock information from the clock circuit, the calendar/clock information corresponding to a time at which the variation in the magnitude of the line voltage is detected, capture a first waveform in the form of a first set of digital line voltage information corresponding to the time when said variation is detected, and generate an event record including the calendar/clock information and the captured first waveform.