A Digital System for Calibrating Active/Reactive Power and Energy Meters

Abstract

A new digital calibration system for ac power and energy met was developed at Japan Eledlic Meters Inspection Corp. (JEMIC) and its performance has been evaluated at National Reseath Council of Canada (NRC). The results at power frequency were betterthan 20pW/W ofapparent power at any power factor settings. IntrdudnGenerally, most of high precision power/eneigy standards are established based on cment comparator [1], thermocouple, etc. On the other hand, recent digital techniques can provide simple approaches forpower/energy meem ent with high accuracy. The digital calibration system described in this paper uses digital techniques to achieve high prwision power measurement Voltage, cuntnt, and phase angle applied to power/energy meter under test are meared individuaRy, and then active/mwative power is determined by calculating results ofthese measurements.

Visualization system for electrical power consumption and its evaluation

“…Figure 4 shows the traceability of the calibration system within the visualization system. The primary power standard [2] consists of the AC voltage, AC current, and phase standards. These systems are calibrated based on national standards such as DC voltage standards [3], as realized by Josephson effects; AC resistance and DC resistance standards [4], as realized by the quantum Hall effect; and the AC–DC transfer [5] and frequency standards, as realized using the atomic fountain.…”

Changes in AC Power Standard in Japan

“…An electric power and energy calibration system (calibration system) [4] was developed at JEMIC in 2004, and it was designated as the national electric power and energy standards in Japan in 2005 to replace the aging AC/DC watt comparator.…”

“…The voltage, current, and phase angle are measured at the same time for one measuring interval (about 30 s). The electric power is calculated from the measured voltage, current, and phase angle using (4). The value of the calculated electric power is compared to the mean of reading of the wattmeter.…”