Digital meters test standby power to IEC 62301

The Yokogawa WT3000-2A and WT210 digital power meters are now certified to carry out the standby power tests specified in the IEC 62301 standard.

The new standard defines the standby mode as the lowest consumption of an appliance not performing its main function, when connected to the mains.

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 1 January 2010.

Standby power refers to the electrical power consumed by appliances or equipment when they are switched off or in standby mode.

Typical examples might be a DVD recorder set to record in timer mode or a dishwasher timed to make use of off-peak 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 1W) 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 per cent or better, measurements down to 0.01W or lower and the capability of including components up to the 49th harmonic (2.5kHz).

Key parameters with specified limits 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, plus the ability to record true average power over a period of more than five minutes.

The WT3000-2A is ideally suited to research and development and laboratory testing and evaluation, and the WT210 is designed for use in the production environment.

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