Hi all; we're using ADE7880 in our project and CT phase error is +4 degrees , ADE7880 datasheet says it can fix -3 ~ +1 degree phase error. Is there anything that I can do?
The phase calibration register can actually correct between -6.732deg to +1.107deg for a 50Hz system as can be seen on Page 37 of the data sheet.
This means that your CT's phase error of +4 degrees can be corrected for by setting the xPHCAL register to -4 degrees.
When I set negative values on xPHCAL register , Phase error is increasing.. I can decrease phase error via setting xPHCAL registers positive value(max 1 degree of course)
That result is surprising because from a CT physics point of view, with a line voltage and current that are exactly in phase, the CT will cause the current to lead the voltage and that is what is trying to be corrected. This is the reason for the phase compensation being more heavily weighted in the negative direction.
Could you please confirm this by either connecting an oscilloscope to the IAP-IAN and VAP-VN inputs or use the waveform sampling feature of the ADE7880 to get both the IA and VA channel waveforms without any phase compensation applied. This will help better understand what is going on.
Do your inputs have any extra circuitry beside the anti-aliasing filters shown in the Test Circuit below?
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