I have enabled ESS a few days ago and I have noticed that the reaction time (roughly 20ms) seems longer now during grid failure.
I also noticed that when I selected a grid code, the UPS function is gray (no selective option).
So my question, is there something else that I should look out for?
Which grid code are you using, out of curiosity?
It will be because when a grid code is enabled the voltage tolerances are wider. And possibly the frequ
So you are experiencing brownout then blackout. Where as the ups function makes it way more sensitive to the grid changes. Not as sensitive as a certified UPS but still keeps most PCs running.
It does depend on the grid code used.
Thanks for the quick response.
The brown-out makes sense.
This install is in RSA, so I might not be familiar with the grid code "variables".
Is there a work around i.e. Other or tightening up the lower voltage?
The grid code is not editable. So that is out.
Maybe there is an option in node red but not something I have looked into seriously.
The reason I am asking is that I am also in South Africa, and have experienced exactly the same. Before, when I was still running with only batteries (no panels), I had no ESS and UPS function selected. I could barely see when the power failed, and no devices were unhappy.
Now, with ESS (because I now have solar panels) and the South African grid code selected - power failures are *painfully* obvious, with a big blink and often some routers etc. will restart.
I don't know if there is a solution.
Indeed, the client is complaining of a very similar situation as yours. As mentioned above, the client was on "Battery" supply during outages, until the installation of Solar panels was introduced with ESS.
From memory (could be wrong), I suspect the LOM (phase shift) could have a dead spot (layman's terms) but as mentioned I am not to familiar with NRS grid code.
One other item also got flagged, but this will be a new questions later (T&C of website) (SOC).
So I am not sure what would work best now i.e. "Gen start" but it is actually the grid or Node red as to read when will the grid failure happen i.e. trigger outage before it happens.
But in a nutshell, the client wants to use as much possible solar that is generated while the grid is on but without the "long" delay compared to normal UPS function.
@Albert de Jongh , what is your set-point currently?
My setpoint is zero watt at the moment.
Depending where you are and what your system is comprised of, can affect your experience.
There are places in SA where the grid does brownout more than others.
Often it isn't purely the grid.
What inverter(s) and batteries do you have?
When voltage dips, it can put a transient load on the batteries under ESS which can be responsible for the power dip.
This is most commonly seen when there is a low battery to inverter ratio, and more likely on systems that use the Pace BMS (BSL, e-tower, hubble etc).
In this scenario, more battery tends to solve the dip.
Some people have resorted to dropping grid prior to loadshedding to work around this issue.
If you want to adjust voltage limits you will need to change the grid code to other or none (prohibits feeding back).
Thanks for the input.
This install is small, 5kva Multi2, 5.12kW Lifepo and 7 kW Solar.
Indeed, I am also not a big fan of the Pace bms, so I normally go for a "aftermarket" 200A bms with build in balancing. Obviously the bms is just my preference and from my experience, it has served me well with all the other installations. Yes, one "loses" the connection, but if you feel inclined to have BMS communication, you can use rs485 with some coding to pull the data through.
Yes more battery could solve the issue, I am just a little irritated that the system works perfectly with normal UPS, but seems to drop a little (when grid fails) with this grid code. So if I can alter some areas (hardware or software), it would be the best option for the client.
Client does not export nor will ever want to, so that solves that.
To make full use of the solar during grid availability and outage, could one use OTHER and make some limits similar to NRS grid code (T&C apply obviously) or a hint would be nice.
Alternatively, No grid code can be used, but I cannot see how to utilize the solar power while the grid is available (if you have a hint on this, it would be highly appreciated).
@Groningen Use other by all means, this is the default anyway for systems that don't have NRS compliance and the SA grid code.
OK, I will try the Other and report back.
However, I am still not satisfied with the solar usage. It would appear that when the grid is available, it does use some solar but not "fully". When the grid fails, more solar is being generated (i.e. consumption is roughly 3 kW with the solar generating 1 kW and the grid is available. After failure of grid, the solar JUMPS to (let say) 2.6kW and the remaining is being supplied by the battery.)
Do you perhaps have a hint or suggestion?
If I find a solution (assuming it is not the bms), I will post it on here. I have also picked up that this happens when the mppt is "feeding" in, so I am not sure if it is something between the transition from solar and grid to solar and battery (or a combination of all three depending on the situation).
I have made the minimum SOC 100% and it would appear that this have solved some of the delay. However, if SOC is 100%, the MPPT is throttling and not supplying all of the potential sun power.
Please post on here if you have found anything.
