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danepb avatar image
danepb asked

Overload warnings on grid connection with Victron ESS regardless of load

Good day All,

I have a Client running a Victron MP2 5kVAwith an AC coupled ABB 5kW unit what shows a daily overload warning. The thing is that there is no power outage at all, or a load to justify the warning in case of the overload. The base load is around 350W.

Yesterday the system turned off due to overload, but the inverter was drawing 50W from the grid and 300W from the batteries respectively.

I have several installs running this configuration with no indication of these warnings. The firmware on all the units are up to date with no high current draw warning from the pylon battery bank either.

I thought it maybe something to do with the grid inverter, however I have seen two warnings at night when the inverter is off.

Has anyone else see or experienced this or have advise on this matter?

Thanks

MultiPlus Quattro Inverter Charger
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nickdb avatar image nickdb ♦♦ commented ·

I have the same issue on a 3kVA multiplus.

It generates an L1 exceedance even though L1 is nowhere near 32A with moderate AC1 loads.

The alarm clears almost immediately but I have not got to the bottom of the issue.

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Guy Stewart (Victron Community Manager) avatar image
Guy Stewart (Victron Community Manager) answered ·

Hi,

Specific to ESS systems, there are some causes of overload conditions related to the grid - please read the FAQs in the ESS manual here - https://www.victronenergy.com/live/ess:design-installation-manual#faq


Generally speaking in on and off grid systems, there is also training on diagnosing inverter overload here:

https://www.youtube.com/watch?v=4SXtGIx0x5w


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nickdb avatar image nickdb ♦♦ commented ·

Unfortunately alarms don't contain any debug info to assist with what happened at the time.

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nickdb avatar image nickdb ♦♦ commented ·

I think I am getting a picture of what might be happening here.

The inverter is choosing to first pull power from batteries instead of the grid, it then feeds in grid over a few seconds reducing the battery load, and when the load disappears it returns some charge to the batteries.

Unfortunately it seems happy to hit the inverter limit when doing so.

It should not be doing this when grid is available and it seems consistent behaviour in my environment when on a sched charge and there is insufficient PV.

I can't fault anything with the grid at this point, so why it is continually pulling battery power makes so sense and particularly in that amount, exceeding set ESS limits.

When changing modes to "keep battery charged" it does not do this but then I lose the ability to use my stored charge at night.

I have logged a case with support and the local distie to assist as currently it makes my solar install somewhat unusable.

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dean-d avatar image
dean-d answered ·

We have a similar thing happening on two ESS installations. The grid in our area is a bit unreliable(power cuts), therefore customers want a backup system for emergency circuits.

If there is a power cut the system operates as it should. But if the grid gets weak due to high load on the network, then the Multiplus can go into overload and turn off.

The result is that there are more power cuts than there would be without the backup system installed.

We have tested the impedance of mains and subcircuits, which when tested are low. Under 0.5Ω

Although I'm not sure if this impedance jumps up during high load on the network and we are not there to test.

Would love a solution to this problem.

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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ commented ·

Hi @Dean_D,

There is a procedure here to confirm if the Loss of Mains detection is the cause of the issue, and some solution for what you can do to correct or workaround the problem for a reliable system :

https://www.victronenergy.com/live/ve.bus:grid-codes-and-loss-of-mains-detection

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dean-d avatar image dean-d Guy Stewart (Victron Community Manager) ♦♦ commented ·

Thanks, @Guy Stewart (Victron Community Manager), Currently relying on the anti-islanding in the Multi. The issue is intermittent, so we would need to disable LOM for a week or two. Without external anti-islanding, I don't think we can do this.

Do you have any recommendations on an anti island device for New Zealand? if we do this test.

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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ dean-d commented ·

Victron stocks part number REL100100000 the Ziehl Anti-islanding relay UFR1001E

But the only way forward would be to talk to your grid supplier/distributor and find out what they are willing to approve.

A once weekly intermittent issue sounds frustrating indeed, most other cases I have seen have this occurring more frequently.

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nickdb avatar image nickdb ♦♦ Guy Stewart (Victron Community Manager) ♦♦ commented ·

That Ziehl relay is seriously expensive, at least here it is.

For smaller installs it would be cost prohibitive being about 50% of the cost of a smaller multi.

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Guy Stewart (Victron Community Manager) avatar image Guy Stewart (Victron Community Manager) ♦♦ nickdb ♦♦ commented ·

As it is independent of the Victron equipment, the best thing to do would be contact the local distributors and see which products are available (and competitive) and approved for use locally.

It is inherent at edge of grid (where this is usually the problem) to be more costly for everyone when it comes to reliable power supplies.

Another option is to not use an ESS system programming at all, and instead use a backup, or 'ignore AC' system where the grid interactivity is less demanding, and grid code compliance standards are less restrictive.

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dean-d avatar image dean-d Guy Stewart (Victron Community Manager) ♦♦ commented ·

Thanks, @Guy Stewart (Victron Community Manager) ill talk to the distributor about the options. Both of our locations are close to the furthest points on the network in our town. I'm sure this has something to do with it.

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