I have read several posts here and on the old forum on the above subject but I’m even more confused. I’m designing an ESS system (with absolutely no grid feed-in) comprising a Cerbo GX, a Quattro 10k, 2 MPTTs and 600Ah of CAN managed batteries. I wanted to use ESS to control grid-charging but now I’m not very sure.
My question: Can I use ESS without grid feed-in but with a grid connected Quattro 10k so that I can prioritize PV and battery consumption and only use the grid for emergency charging without installing an additional anti-islanding device?
This is largely a question of what the Quattro 10k can and can’t do. There are no local regulations. I follow UK regulations as a guide. The ESS manual states ''ESS always requires anti-islanding”. The manual further states that the “MultiPlus” is allowed to run ESS using the built-in anti-islanding system. The Quattro is not mentioned. Even more confusing, some threads say only the MultiPlus-II has such a system. Some people say they have to fit an external anti-islanding device to the Quattro to make it compliant to UK regulations while others say that such a device is not required.
Of course, all these questions can be avoided by buying a MultiPlus (or MultiPlus-II) but this is not Ideal; I already have a Quattro laying around. An anti-islanding device is not available locally either (I know Victron sells such a device); I would have to import it at considerable cost.
There is no such thing as absolutely no grid feed-in when an inverter runs in parallel to the grid. Even with an external grid meter and CTs. There will always be unintentional power export to the grid when large loads shut off. If the input relay is connected to the grid, it can export power, even if you tell it not to.
It is possible to tell the Quattro to Ignore AC input in software, which will open the input relay to the grid. There are UK grid codes for ESS that should be sufficient for you to operate the Quattro when the input relay is closed.
However, I don’t know UK regulations on anti-islanding, so I cannot answer about the legality of it. Hopefully a UK person will provide clarity.
My impression is that only Germany required a separate anti-islanding device. Could be wrong though.
Point taken. I should have said no deliberate feed-in. Any unintended feed-in is ok.
Does the Quattro hardware run ESS with the proper software settings without an external anti-islanding device? This is what I plan to do as I look in the legality of the system.
If you have no loads between the Quattro and the grid, the Quattro and a Cerbo GX (or other GX device) will do the job.
If you do have loads on the input of the Quattro, you can get a Grid Meter like the VM-3P75CT to measure the grid power where it enters. This will largely prevent export to grid by using Current Transformers (CTs).
The normal ESS software uses PV and battery power for loads first, if above the minimum State of Charge.
If the loads exceed what is available, it will pull from the grid. The Grid Setpoint determines how much of the grid is normally used. I keep mine at 100 W.
You can manually set the Quattro in the console or VRM to use the inverter only, which will disconnect the grid input relay. If you want to disconnect the grid in software, you can use NodeRED to do this programmatically by Ignoring AC Input.
You must select a UK grid code like G99 to properly handle islanding and Loss-Of-Mains (LOM). I recommend you figure out what your local jurisdiction requires before connecting to the grid in parallel.