I am looking at putting in a number of Iotawatt units on my property. In part of this I have a 3 Phase supply servicing multiple buildings. On three of these buildings I have individual solar single phase solar systems each feeding into one phase. So in the end, on the one three phase supply, there is a Solar input on each phase, but each of these input occurs in a different building.
To try and spell this out some:
Building 1 is three phase, it has a single phase 6.6kW solar system on Phase A,
Building 2 in three phase, it has a single phase 6.6.kW solar system on Phase B,
Building 3 is single phase, it has a single phase 6.6kW solar system on Phase C,
Building 4 is three phase (on same supply) with no solar system.
Building 5 is single phase (on same supply) with no solar system.
My main question in scoping the iotawatt configuration is whether to go with a single VT for reference (in the three phase buildings) or should I use three (one per phase). Since in a building the Solar feeds into one phase, and the other two phases don’t have solar (in that building), but do have solar from other buildings coming together at the main distribution board. Is this likely to cause accuracy issues in measurement if I only have one VT for reference in each building? If so what is the likely magnitude of the inaccuracy?
I know this is all a bit confusing when spelled out in words, so I can put together a schematic diagram if it helps to understand the situation.
Overall, I am keen to know detailed usage by circuit in each of the buildings, and be able to separate this from the solar generation data appropriately. Each Solar has SolarEdge Inverter, with its own CTs for all phases, plus the main distribution board has a SolarEdge gateway for feed in / grid use, but this only gives me part of the energy consumption picture.
I think what I need is an iotawatt in each building with CTs for building supply, Solar input, and then for each appropriate circuit I want to measure. I am basically planning on only the single VT and a power supply, but not sure on the accuracy impact of this.
Then, somehow I then need to bring all this together (which I undestand can be done a few ways), and blend this with the other solar and usage data from my main house and use all of this to optimise energy use, via Home Assistant, and maximise solar feed-in and where it is viable.