Isn’t it possible to run ESS with the Multiplus-II on IT grid? I can’t find a way to turn off the Ground relay?
You can set that in ve config software under inverter settings
I can do it on my old Multiplus. But not on the Multiplus-II. It’s greyed out. If I change grid code, to one that allows to turn off the Ground relay. I get an error saying that I can’t use ESS assistant.
Then its the grid code force enabling it. Which grid code are you trying to use?
Like I said it’s not like this on my old Multiplus.
The Multiplus is connected to a Cerbo, and the Multiplus-II is using it’s built in GX. Maybe that’s the reason for the difference?
No, that makes no difference, you could check the old one settings to see what grid is set to
It was at Europe a few weeks ago, before I moved the Cerbo to my Multi RS. If you know any grid code that is ok for IT grid, that let you untick Ground relay then I can use that.
The reason it works with the old MP is because there is only a single mains relay in the MP1, and if you are using it in an ESS configuration you most likely need to use an external grid and plant safety relay inline with the ACin. For example a Ziehl UFR1001. If you are using the MP1 as an ESS without an external protection relay you are likely violating grid safety, but that also depends on your local laws. Im sure theres a warning somewhere when setting this up that informs you about the need for an external safety relay.
The newer MP2 has two mains relays wired in series, and can do the same grid and plant protection internally without the need for an external relay. This then makes it mandatory to set a gridcode in order to use ESS.
EN 50549-1:2019 does not inherently exclude IT grids, but the requirements to meet this code make it necessary that the Neutral is grounded.
You cant just select a gridcode that works best for you (yes technically you can, but you may violate local laws), your mains supplier or the national electrical board approve which code you can use. Where are you planning to use the MP2, wich country is this IT grid located in? Belgium perhaps? Theres been a few discussions about using Victron equipment in 3x230V no-Neutral belgian grid, so you could ask those persons which code they needed to use.
In Norway the 230V IT 1 phase doesn’t have neutral. So it’s not possible to use ground relay. In the old Multiplus it’s possible to untick the ground relay.