I’ve installed (together with an electriction…) 3 MP II 5000 combined on a set of pytes batteries as a 3-phase system. Grid is on AC in and the whole house + some inversters is on AC out…
As grid meter, I’ve installed a VM-3P75CT. Actually everythings working, but I’ve realized that apparently I’ve messed up the phase mapping on the MPs as when checking the values, I realized that L1 on the Grid Meter shows L2 consumption on the MPs and vice versa. I’m sure the Grid meter is mapped correctly to my 3 phases, so it must be the mapping in the MPs.
This actually leads to incorrect consumption values and is a bit annoying. Also the grid setpoint of 0 is basically missed slightly (in both directions) more or less all the time and I see that I’m consuming from and delivering to the grid unnecessary energy. (We’re talking about 1 kWh a day or so…)
Now I’m wondering how to fix this in the easiest way (without taking down the whole system) and would appreciate your help.
The first thing I’m confused is how (and if) the MPs in a 3-phase system determine the grid rotation. Actually the rotation from Grid side is correct and so it is on the grid meter, but as L1 and L2 are switched on the MPs, I wonder why there is no rotation error appearing.
Do the MPs actively measure the roation and throw that alarm in case it’s incorrect or do they only recognize a reversal of the rotation?
The 2nd questio is: How would you fix that rotation issue? As I don’t mind in reporting what’s L1 or L2 I could either:
Switch L1 and L2 on the grid meter (easy and no outage → Wife Acceptance Factor high)
Reconfigure the MPs and assign them the other way around (outage → WAF low & I’m not sure about rotation error)
Using a phase rotation meter establish the rotation is correct at meter.
If this is correct then the AC in on your MPs will also be correct (very important in Multi’s configuration this to be matched. Verify this using the Flashing LEDs function)
If there are PV inverters on AC out, make sure the phase sequence is also correct, else you will have all sort of weird issues.
In theory you should be able to correct this at smartmeter input.
What I’m confused about is the fact that I’m pretty sure that the rotation is incorrect on the MPs.
So they are configured to be 123, but are 213. I’m wondering what kind of effect this has and why there’s no rotation error so far.
I cannot check the wiring easily as it goes bundled through a wall and I can’t measure it either.
The grid rotation is correct (checked with another smart meter in my installation) and in line with what the VM-3P75CT meter, PV and the actual smart meter from the electricity company tells me…
Do the MPs follow the grid as long as it’s there and then switch the rotation once the grid is lost? Because then I’d definitely have to re-assign them correctly, if this is not the case I would just switch it on the grid meter (VM-3P75CT).
No, they follow the way they are setup at the beginning. Get a cheap phase rotation meter and measure at every point. It will also tell you which wires are crossed on the path. Or with a simple continuity tester you could also achieve same. I’d say correct this first and take it step by step.
So i’ve really ordered a pahse rotation meter and measured the rotation and it turns out, the grid is connected counter clock wise to my installation and by messing up the assignment of the MPs, they were connected and defined accidently clock wise. This explains why they new threw a rotation error…
So i’ve switched the grid meter assignment and just ignore the electricity companies smart meter from now on.