I use ADE7880 to measure AC power energy by using line cycle accumulation mode, and get the good accuracy of xWATTHR in measuring resistance load (PF=1) and motor (PF=0.26).
While I give the standard 110 AC source with 3-order harmonic voltage of 50% THD on the resistance load, the voltage wave is distorted to two-peak wave and I get almost
20% error on the xWATTHR compare with Fluke 434 meter. Because the resistance load only, the PF is still 1 even the giving distortion voltage.
I have no idea about what is going on in my measurement and how to explain the situation. May I have any suggestion for this issue? Thank you very much
Can you provide more information:
what is voltage divider values used for voltage channel.
Are you writing xVgain register?
Do you get this on all channels?
There is a good possibility you are railing the modulator. If at 110v the input signal is somewhere near full scale of the ADC then you add on 50% thd you might be railing the input. If you can't do waveform sampling try Vpeak register to capture your peak value.