ESS Quattro 8k drops load for 30 seconds on generator AC-IN2 during absorption

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hennie-mouton asked Apr 22, '22

ESS Quattro 8k drops load for 30 seconds on generator AC-IN2 during absorption

On-grid (50 Hz, 230V single phase) ESS System MPPT and batteries on DC, with CCGX and Quattro 8k feeding load, with mains/utility power on AC-IN1 and generator (49-52 Hz controlled) on AC-IN2.
I have been previously advised to put gen on AC-IN1, but as mentioned by other posts, I need the mains input to always have priority. I have LOM to B on mains and no LOM on gen, and enabled wide voltage and frequency and UPS function in the ESS assistant.

The power would go off, and the gen starts by independant control. The ESS system does not use the gen power right away but first inverts power from batteries and MPPT until batteries reach 96%, at which time the AC-IN2 (which have already had Gen power for a while) is engaged. The system drops the load for about 30 seconds when engaging gen power, despite no wide frequency or voltage swings taking place. Very irritatiing, but not the worst, as this usually happens not too often. Current limiting keeps the system from using too much gen amps, so the load is fully carried, and a few spare amps is used to charge batteries together with MPPT power.

But then, at random intervals, it seems the amps, (but not V, like in a disconnect) are dropped from the Quattro input AC2 through to the output. The input voltage stays normal or go up a few Volts as a 4kW load is dropped for a few seconds. No warnings or any frequency or load changes are evident. It might be a 30 second problem that does not show up at 1 minute recording intervals in detail.

See below zoomed images of the recorded parameters at the time of one of the drops. It happens every 20 to 60 minutes when on generator power. The 4kW load on ESS is critical, so an independant UPS after the ESS is tripped to battery when the ESS load drops, and these UPS batteries are only strong enough for about 70 seconds, so after 2 such drops I have to manually bypass the whole ESS and power the load directly from generator, so no sun power nor longer term battery backup for when the gen perhaps fails.

1) Is there no way to enable a "debug" function or similar in the Quattro or CCGX to see the exact decision being made that leads to the load drop?
2) What can I try to make this stop? I can send my .rvsc file, and the settings on my CCGX, if somebody could perhaps study it and point out flaws in the setup, or give somebody access to the live system if required.

Graph set 1

Graph set 2

Any help would be appreciated.

quattro 10kva

essdropgraphs1-20220423-1353.png (166.1 KiB)

essdropgraphs2-20220423-1353.png (129.3 KiB)

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shaneyake commented · Apr 22, 2022 at 10:06 PM

What country code are you using?
Check the UPS check box.
Seems like UPS function is turned off. It should only take 20ms to transfer.

What firmware version is the Quattro on?

Can you explain why you want the grid to have priority and not the generator?

Can you post a screenshot of VE.Bus Warnings and Alarms during this time?

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Paul B shaneyake commented · Apr 23, 2022 at 02:35 AM

I would suspect that he would want the grid priority as on a grid failure the gen will take over but if the grid returns then it should switch back and take grid power - then the generator is stopped. the gen is a backup generator

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hennie-mouton shaneyake commented · Apr 23, 2022 at 07:36 AM

AC1 priority: Gen is separately controlled as backup for a wider area. If grid returns, and gen keeps running, my ESS should draw from grid.

I am in South Africa with - Country code "other", LOM on AC1 = B, LOM on AC2 = disabled.

UPS function is on.

VE Bus warnings and alarms shown in VRM screenshots above - no warnings or alarms whatsoever after the initial grid fail alarm.

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ve-grid.png (22.7 KiB)

Modifications Space

Node Red Space

Answer 1 · 2022-04-23T02:43:31Z

Paul B answered · Apr 23, 2022 at 02:43 AM

Try turning week AC on and see if that stops the gen from dropping in and out.

also try turning the country code to none as a test ( the ess will have to be removed) once you have it stable then turn things back on one at a time

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Answer 2 · 2022-04-23T08:33:38Z

hennie-mouton answered · Apr 23, 2022 at 08:33 AM

It's not a repeated gen dropping in and out - I had that problem some time ago (with various grid codes tried) and got it fixed with the Other grid code.

It's one 30 second dropout on initial gen engagement, and then smooth running, followed by random dropouts of perhaps 30 seconds in duration after running on gen for 20 minutes or 2 hours.

When I manually bypass the ESS, and power my 20 A load directly from 20 kVA generator, there are no dropouts, ever.

Weak AC is to help weak generators as I understand, but my generator is not weak and does not need gradual current rampup: the gen can supply 80 A, and the ESS uses max 25 A from gen (current limited), while 40+ A is always used by directly generator powered equipment at the same time. None of these directly gen powered equipment experience noticeable power drops when the gen is engaged to the ESS system. The gen Voltage normally drops/increases between 229 and 235 V when en|disenaging the ESS, while the gen's current draw jumps by 20 A or more.

The major dropout is at random after the generator has been engaged for some time, with no drastic load, frequency, solar, etc. changes - see VRM graphs above (click on picture names to enlarge and see the detail), that shows warning, frequency, voltage, etc. at the time of one of these dropouts

Site: https://vrm.victronenergy.com/installation/42154/share/1713e1eb

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Paul B commented · Apr 23, 2022 at 09:02 AM

Weak AC Is for generators with a bad sign wave it does not mean the gen is weak.

so try with it on and see if it stops the issue also try with UPS off - and weak power not ticked and then try both.

in preferance its best to avoid using weak power in my option as it reduces the charging performance of the Quattro (I think)

try turning power assist off as well.

only do one at a time untill you resolve the issue

YES I KNOW you have a 25 amp limit set BUT - Note a large load ie a motor may exceed the internal 100 amp transfer limit for mili seconds - . this will also turn the ac2 off so maybe look for something restarting at the point of disconnection - ie a large freezer motor

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shaneyake commented · Apr 23, 2022 at 12:46 PM

What do you mean by "Bypass ESS"? Bypass the inverter completely or set ESS to external and let it stop.

There is the possibly a load somewhere in the system that is causing a fast change in voltage or frequency. VRM shows an average valve for 1-15mins depending on how you set it up. It won't display any trasiants.

The inverter should go into passthrough mode when an upset like that happens and not a total shutdown.
You can tighten your voltage control to like 200V to 250V instead of 180 to 270.
This helps the inverter disconnect faster and helps prevent a shutdown.
Have you updated the firmware to the latest to see if that solves it?

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Answer 3 · 2022-04-25T16:31:06Z

Paul/Shane, thanks for the suggestions. The Quattro firmware is v496.
@Paul B
Save for the Weak AC, I have tried all your other suggestions before without success. I will try the Weak AC, depite the power factor warnings, but let me explain this:

1) My ESS supplies a critical sub-load of 4.3 kW. This can be perhaps go to 5 kW or more if the batteries are very flat, which I do not allow, as my gen (already running for some time) is engaged when the batteries reach 96% SOC. So the current limiting is on the amps used to charge the batteries, not on the amps powering the load, as the load does not change. The load drop happens even when the batteries are on absorption, i.e. request lowish charge amps.

2) When the Quattro drops the load, the monitoring shows that the Amps fall away and the gen voltage seen by the Quattro INcreases slightly, and then goes back to what it was before the load drop on re-engagement of the load. This is not consistent with a sudden load increase or other electrical change triggering the drop.

3) The rest of my electrical consumption system is the "grid" as the ESS sees it, but are still my loads, and carried by the same gen, and can reach maybe 65 A at most, but usually draws around 40 A. It is a laboratory, so furnaces and aircons (most are inverter types soft that starts|stops) start and stop, but there are several so this starting and stopping is usually staggered, so they change the load by perhaps 3 kW over a few minutes. But this happens all the time, and the load drop does not coincide with any specific load increase|decrease that I could find.

Regarding how I BYPASS THE ESS:

I have a manual (generator type isolator) swith by which I can electrically isolate the whole ESS system from the load and all AC. So then all my loads run as if the ESS, etc. does not exist. The solar panels and MPPTs work in isolation to charge the batteries, but cannot draw nor provide current through the Quattro as it's disconnected. So gen or utility power flows directly into the sub-load. The current draw on the gen is still similar to what it would it be if the ESS was engaged, save for a few amps used for battery charging. Now all loads draw perhaps 60 A and all run fine, but my critical load is now exposed to generator failure, etc. if that should happen.

The point of mentioning the isolation is to show that it is not the generator dropping the load or doing funny power things, as even a sensitive double conversion electronic UPS, downstream from the ESS, does not go into bypass or do funny things when running straight from gen, and syncs fine with the incoming AC.

@shaneyake
I do not want the Quattro to drop out at all. It could go into passthru for all I care, which would be fine as the load is not dropped; but it does not do that, it just drops all amps going in and out of the Quattro, and there are no errors logged. Surely if the Quattro experienced a shutdown or some other fault it would log an error or warning.

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