I am running into a very similar problem as the one described in this older thread
One phase has a higher load than the other two, leading the MP2 set up with total phase regulation to feed back to the grid almost constantly, even if I’m only pulling 400 or 500w.
In my case, the loads are on the AC Out and there’s a 20kW Huawei inverter that supplies power to both AC loads and Multiplus’ batteries. In the peak hours that the system has energy surplus, the AC voltages increase close to 250V on two phases eventually triggering the Huawei to restart.
@schollex Do you think it would be possible you could share your NodeRed code that disables the feed in? By the way, can you control the feed in per phase? How does that affect the multis total phase regulation algorithm?
First of all, thanks so much for the time you put into making and sharing this!! I’ll try to implement it in the following days.
I’m still trying to figure out how the multiphase control works in the MP2. Below is screenshot from earlier today. If the AC loads are 3.5kW and the battery is supplying 3.8kW, why the heck are the MP2 pulling 13.3A AND exporting 6.6 on the other 2 phases? Can’t just the inverter hooked to L1 invert whatever the loads are pulling and that’s it? Why do they have to mess with the grid?
@owenb79 I have a follow up question about your code. If the PV inverter connected to the AC-out has surplus energy, the batteries are charged and loads are supplied, what’s going to happen if the MP2 disables feed-in for a second?
I don’t know, I only run a single phase feed with 2 phases. I am pretty sure to get perfection is to set a multi to each phase with its own battery and cerbo. I adapted the code from this flow I use to cut feeding when I lose communication from the energy meter. I have been running disable feeding for about 24 months now. Full empty I don’t know just works. I have alarms for over power on one phase and have not had one since. If it needs tweaking the code is simple or if you need help ask.
Edit, I will add will probably work like PWM with the code I have will disable and check 1sec later then adjust. I find 1sec inputs to the cerbo are fine real time data will overload it.
There are 2 MPs in my setup. Continuously, a 3 min average of AC-difference L1 vs. L2 is calculated. Every 10 min is evaluated, whether this difference exceeds a threshold. If so, feedin is disabled and 3 sec. later enabled again.
In a previous version, I used a VEbus-reset for rebalacing, but this is much more “hardcore” than the disable-feedin-way.
The homeassistant-node is not relavant. flows.json.txt (17,0 KB)
After observing some grid instabilities we’ll just deem these issue as grid problems. The rest of the town has also reported problems with grid overvoltages.
However in the meantime the shop owner kinda changed his mind about the interaction between the batteries and loads. These are his ideas in a pseudo ptyhonesque code:
every 5 sec:
if weekday and between 6am and 6pm:
if soc < 95:
if ac_out < 0:
grid setpoint = ac_out*(-1)
limit inverter power disabled
else:
grid setpoint = 50
limit inverter power disabled
else:
grid setpoint = 50
limit inverter power to 0W
else:
grid setpoint = 50
limit inverter power disabled
to sum up, the idea is to always charge the batteries with surplus pv but not allowing the batteries to discharge in weekdays during working hours (except in grid loss obviously). Only outside working hours and weekends should the batteries be allowed to discharge, here ESS would work in the default mode.
Is that something that could be achieved in an easier way or it should be implemented in NodeRED? The thing is, I’m not taking the easier route of setting ESS to keep batteries charged because then it would recharge them from the grid in lack of excess PV production, and that’s not the idea.
Additionally, given that this is a 3 phase system, can I set a total grid setpoint or should it be set individually per phase?
