Hi all, Im trying to design quite specific system with Quattros which would be able to use two grid inputs (really both would be grid, no generator). In case it would be connected to input 1, I would need the grid metering in ESS to be done by grid meter which actually is on input 1 and similarly, if the Quattros were connected to input 2, I would need the grid metering in ESS to be done by grid meter which actually is on input 2. This means there would have to be two meters with the role “Grid meter“ connected to cerbo and in default, both would be showing some measurements in cerbo since even though the Quattro is connected only to one grid at a time, both grids are active and therefore both grid meters have a power supply and show data. Has anyone crossed this issue? Im still in the planning phase, so I havent really tried how the system behaves when two grid meters are connected to it…How does it chose the “right“ grid meter? One thing that comes to my mind is that i would just interrupt supply voltage for the grid meter I dont want to use and it would just get lost from cerbo and therefore cerbo would see only the correct grid meter, but that seems kind of brutal and Im still not sure how would it work…Also in my specific case, I dont really need both grids to be measured by grid meter, one grid could be measured by “Inverter” and second one by “grid meter” and this settings I could change in node red, so…this will probably work ok, but Im just curious how to do it if I really needed both inputs to be measured by grid meter. Thank you for your answers!
One possible solution with a “grid meter” that has CT’s for current sensing:
Meter Voltage connections are taken from inverter AC out.
Meter phase CT’s: Each of the 3 CT’s has the phase wire from source 1 and source 2 running through it.
If an AC source is present, the inverter will detect, and select that input, so under this condition, the AC voltage out of the inverter is the same as the input, hence the meter will automatically have the correct voltage.
Likewise, current will only flow through one of the 2 source connections, so the meter will automatically read the input current from that source.
However, the total energy recorded by the meter will be the sum of that taken from both sources.