Hello,
while testing ADE7868 on a custom board we are experiencing linearity issues on the current channels.
We have 2500:1 CTs connected to the current channels, these are the values obtained for various points of operation (ADE uncalibrated).
P.1 I=0.28A
I1 3632 I2 3738 I3 3475 V1 3014804 V2 3011450 V3 3014501
I1r 0.007709251 I2r 0.007490637 I3r 0.008057554
P.2 I=1.62A
I1 19807 I2 19786 I3 19506 V1 3002985 V2 2999628 V3 3002679
I1r 0.008178927 I2r 0.008187607 I3r 0.008305137
P.3 I=2.91A
I1 35405 I2 35204 I3 35195 V1 3014990 V2 3011596 V3 3014684
I1r 0.008219178 I2r 0.008266106 I3r 0.00826822
P.4 I=3.34A
I1 40660 I2 40387 I3 40288 V1 3011103 V2 3007706 V3 3010741
I1r 0.008214461 I2r 0.008269988 I3r 0.00829031
I1=AIRMS I2=BIRMS I3=CIRMS
I1x=Amps/LSB ratio
As you can see, the response is not linear, and phase current 3 behaves strangely.
We already verified the CTs and their are linear, the behaviour is the same even swapping CTs.
Attenuation networks and burdens are the same on all the 3 lines.
What can we do?
Thank you.
