Hello,

According to IEC-61000-4-30, for class A energy meters :

The measurement shall be the r.m.s. value of the voltage magnitude over a 10-cycle time

interval for 50 Hz power systems or 12-cycle time interval for 60 Hz power system. Every

10/12-cycle interval shall be contiguous, and not overlapping with adjacent 10/12-cycle

intervals...

The 10/12-cycle values are then aggregated over 3 additional intervals:

– 150/180-cycle interval (150 cycles for 50 Hz nominal or 180 cycles for 60 Hz nominal),

– 10 min interval,

– 2 h interval.

As we know, the first method ADE7880 uses to calculate rms voltage and current is to low-pass filter the square of the input signal (LPF) and take the square root of the result and this calculation takes place continuously (although the update rate of rms registers is 8 kHz) without any specific time interval for restart the calculation.

How can we use ADE7880 rms results for satisfying the standard? Is it enough only to read rms registers every 10-cycle (for 50 Hz system) and use them as a base for aggregation (over 3 s, 10 min or 2h time intervals according to the standard)?

Thanks.

Hi,

You cannot use the ADE7880 RMS Register for that. You have to use the ADE7880 Waveform sampling here and perform the RMS. Because there is a certain procedure for IEC-61000-4-30.

There is a sync required to perform this standard.

And you also have to take note of how is the rms being defined there.

Hope this helps,

Aaron