Yokogawa - Power meters certified for testing standby power to new IEC 62301 standard

In tests carried out by Kema Quality, a global, independent accredited calibration laboratory and a leading authority in energy consulting, testing and certification, both instruments were shown to comply with all requirements for test equipment specified in the IEC 62301 standard.



IEC 62301 has been introduced in response to the growing awareness of limited energy resources and the resulting urgent need for power savings in household electrical appliances. This need is emphasised by the EU directive 2005/32/EC on standby power losses for both office and household electrical equipment, which comes into effect in all 27 EU member states on the 1st January 2010.



Standby power refers to the electrical power consumed by appliances or equipment when they are switched off or in a standby mode. Typical examples might be a DVD recorder set to record in timer mode or a dishwasher timed to make use of offpeak electricity tariffs.



Measurements of standby power are generally regarded as challenging because general-purpose power meters do not usually have the accuracy to measure low power values (typically less than one watt) accurately. In addition, average measurements over a period of time may be required to compensate for the effects of surges on the AC power lines.



The IEC 62301 standard describes the test methods and requirements for both the mains supply and the test equipment. The EU directive prescribes limits for standby power values and the timetable for their compliance.



The main requirements are for a digital power meter with fundamental active power accuracy of 0.5% or better, measurements down to 0.01 W or lower and the capability of including components up to the 49th harmonic (2.5 kHz).



Key parameters whose limits are specified in IEC 62301, all of which are met or exceeded by the Yokogawa power meters, are total harmonic distortion (THD), crest factor, accuracy, resolution and stability at different power levels, and the ability to record true average power over a period of more than five minutes.



The two Yokogawa instruments which meet these requirements are the WT3000-2A, which is ideally suited to R&D and laboratory testing and evaluation, and the WT210, which is designed for use in the production environment.