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The precise measurement of electric power will increase in importance because of the growth of power consumption and the deregulation of electric utilities. An electric power and energy calibration system was developed at the Japan Electric Meters Inspection Corporation (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 methods of establishing the electric power standard at foreign National Metrology Institutes (NMIs) can be classified roughly into a method by a sampling wattmeter, a method by the principle of the current comparator, and a method based on dual‐heater multijunction thermal converters. This article describes the transition of the electric power and energy standards in Japan and in foreign countries. Copyright © 2008 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc.

No abstract

A magnetic laboratory test facility must usually be shielded because external magnetic fields, such as the earth's magnetic field and magnetic noise, influence measurements. In a laboratory without magnetic shielding by ferromagnetic materials, a compensation system for the external magnetic field is necessary so that a magnetic field of less than 10 6 nT can be measured with high accuracy. In this paper, a compensation system for the external magnetic field is proposed, which is able to automatically remove only the components of the external magnetic field by the generation of a constant magnetic field. It is shown that a stable magnetic field without any influence of external magnetic fields can be generated by using a magnetic field generator with compensation for the external magnetic field.