BS EN 62053-24:2015+A1:2017

This part of IEC 62053 applies only to newly manufactured transformer operated static var- hour meters of accuracy classes 0,5 S, and 1 S as well as direct connected static var-hour meters of accuracy class 1, for the measurement of alternating current electrical reactive energy in 50 Hz or 60 Hz networks and it applies to their type tests only.

This standard uses a conventional definition of reactive energy where the reactive power and energy is calculated from the fundamental frequency components of the currents and voltages only. See Clause 3.

NOTE 1 This differs from the approach of IEC 62053-23, where reactive power and energy is defined only for sinusoidal signals. In this standard reactive power and energy is defined for all periodic signals. Reactive power and energy is defined in this way to achieve proper reproducibility of measurements with meters of different designs. With this definition, reactive power and energy reflects the generally unnecessary current possible to compensate with capacitors rather than the total unnecessary current.

It applies only to static var-hour meters for indoor and outdoor application consisting of a measuring element and register(s) enclosed together in a meter case. It also applies to operation indicator(s) and test output(s). If the meter has a measuring element for more than one type of energy (multi-energy meters), or when other functional elements, like maximum demand indicators, electronic tariff registers, time switches, ripple control receivers, data communication interfaces, etc., are enclosed in the meter case, then the relevant standards for these elements also apply.

NOTE 2 IEC 61869-2:2012 describes transformers having a measuring range of 0,05 In to Imax for accuracy classes 0,2, 0,5, 1 and 2, and transformers having a measuring range of 0,01 In to Imax for accuracy classes 0,2 S and 0,5 S. As the measuring range of a meter and its associated transformers have to be matched and as only transformers of classes 0,2 S / 0,5 S have the current error and phase displacement characteristics suitable to operate a class 0,5 S / 1 S meter respectively as specified in this standard, the measuring range of the transformer operated meters will be 0,01 In to Imax. Reactive meters intended to be used together with non-S transformers are, therefore, not covered by this standard.

It does not apply to:

• var-hour meters where the voltage across the connection terminals exceeds 600 V (line- to-line voltage for meters for polyphase systems);

• portable meters;

• data interfaces to the register of the meter;

• reference meters.

The dependability aspect is covered by the standards of the IEC 62059 series.

The safety aspect is covered by IEC 62052-31:2015.