I know you said you wanted to do this as a project, but…
Have you considered using an iotawatt
It has a Vref input and 14 phono jack inputs for current transformers. However you can also use 2 of those inputs for extra Vref for other phases
Three Phase Capability
IoTaWatt can handle three-phase power in several ways. The easy way uses just one voltage/phase reference transformer plugged into any of the three-phases. Power measurements on the two other phases are made using a “derived” three-phase reference signal.
For utmost accuracy, two additional transformers can be connected to inputs for “direct” voltage and phase reference of all phases.
If you do that, you’ll have 3 voltage references, and 12 current inputs which is what your design has.
If you still want to go ahead with your project, iotawatt is open software/hardware and there’s some good technical info on the site.
I’m busy redesigning my design with a external ADC. I came across the IoTaWatt, it is a very nice product and I’m looking at it for inspiration because I wanted to use the same ADC in combination with a ESP8266.
Bud despite that I’m planning on continuing to make my own design. First because I want zo practise in designing PCB’s and I think it is a bit tedious to use those separated AC to AC adapter, I’m trying to make it one unit with only voltage clamps as external part.
And also, the IoTaWatt is 169,- for only the base bundle. You will have to add 2 reference transformer and the CT clamps wat will make it about 279 with discount. I think that this is a bit steep for the original purpose.
I will add that I think that is reasonable priced for the precision you get.
That’s is also a good idea. Before starting this project I was looking into something like this to keep track of the solar panels. Bud then I started this PCB design and dropped it because I also could use this project for this.
Further, looking around it cost about €140,- for only 3 fase, to get the same inputs as my design or the IoTaWatt box you will need 5 of those. I don’t have that match space also, being a intrusive way of measuring, I could have used a ACS712 power meter or something.
These considerations combined I don’t think it is a real option for this project.
If the project fails I probably go back to something like the Eastron to measure the solar panels.
I’m sorry if I sound a bit un unappreciated, I’m really glad that you guys think with me on this. For example, without you guys I never discovered that the internal ADC is to bad to use in this project.