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theeldar avatar image
theeldar asked

Grid Meter Position in ESS Configuration

Hello Community,

I have a problem with the position of the grid meters in my ESS configuration.

I am not allowed to install another meter near my provider's grid meter.

My Multi Plus 2 can only be installed parallel to my Carlo Gavazzi EM24 eth and the feed-in of the Multi would not be recorded on the EM24 meter. However, I could connect the Multi behind a Carlo Gavazzi ET112, but it would not be able to measure the rest of the consumption. Can I configure an ESS system with zero feed-in with this setup?

Regarding
TheEldar

Multiplus-IIESSEnergy Meterem24
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sharpener avatar image
sharpener answered ·

Yes, I had not got the "position" option to work with the AC Load either but then the Remote Console crashed before I had finished experimenting. Fortunately it seems to have come back to life when the router was re-booted early this morning.

This user here seems to have a separate display for AC loads on AC In and Critical loads on AC Out.

Another idea...

I do not know if the Victron current transformers (CTs) have an internal load resistor (burden resistor). If so the output will be in the form of a voltage. You could then have one CT on the feed to the loads and the other on the feed to the Multi, connect them in series to add or subtract the voltages and set the Multi to use external sensor. If you put them the correct way round on the cables it will then use the difference signal as the true measure of the net export current, so as to achieve zero grid feed-in.

WARNING If the Victron CTs do not have internal burden resistors then this will not work and may give rise to dangerous voltages.

Hopefully someone else will know and add a comment.

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sharpener avatar image
sharpener answered ·

You do not need an external meter to achieve zero feed-in under ESS. If there are no loads on the AC In side of the Multi its internal current sensor will do the job. If there are such loads you can use a remote current sensor between them and the supply. There are topics here which state this results in a faster control loop and more accurate zero feed-in than using an ET112, as the digital signals from this have to be processed in the GX device.

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theeldar avatar image theeldar commented ·

Hello,

first of all, sorry for the very late reply.

I have drawn a schematic diagram for clarification.
gridcabeling.jpgUnfortunately, I am not allowed to adjust all the wiring. Therefore, the EM24 and the MultiPlus2 must be spatially separated from each other and I can not feed with the MultiPlus2 behind the EM24 but only in front of it. Due to the distances and structural conditions I can also not use RS232, but must use Ethernet.


I can currently feed, constant or surplus from solar but I have not found a configuration with which I get the feed correctly displayed. The calculation is of the opinion to show Grid and MultiPlus2 power as AC load and not as feed.

Is there a way to configure this correctly or does another meter help, fass the MulitPlus can not do that?

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sharpener avatar image
sharpener answered ·

The "New Meter?" in that position will not measure anything different from the internal sensor in the Multi.

Maybe you can connect the EM24 in addition, and program it as an external AC load as in the screenshot below. There is also a "Position" screen which allows selection of AC 1 In, AC 2 In and AC Out. In your case it would seem that AC 1 In might give what you want, the Multi will not know the connection is through the payment meter.

I have not however been able to test this, as the experiment has killed my Remote Console, hopefully it will recover. Fortunately the Multi itself seems to be working as shown on the VRM Dashboard.

HTH


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1660231390811.png (37.1 KiB)
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theeldar avatar image theeldar commented ·

Hello sharpener,

I have now set the EM24 to AC loads. After that I had the same problem as you. Restarting the Cerbo has helped.

However, then the feed-in only works when I set the MultiPlus2 as a grid meter in the ESS menu.

Now I see the feed-in from the Multi but I still don't see the AC loads correctly. I can see the graphs under Advanced and the values though.


The function for the position I have not found so.


It seems as AC-Load only the Critical-Loads at the AC-Out are measured.

Strange.

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gazza avatar image
gazza answered ·

Just to be clear.. Normally your electricity(payment) meter comes complete with tails that feed your consumer unit, which is "your property", I am not sure what regulation does not allow you to include your own energy meter in that consumer unit, or even between the payment meter and your consumer unit where it would be allowed to have an isolator switch?
Also you talk of AC IN-1... there is only one AC IN, which can be used bi-directionally as per the image attached. On your diagram your Loads are shown connected after your EM24,is there no way that your Multiplus 2 could get an AC IN feed from that same point?


screen-shot-2022-08-12-at-173051.png


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theeldar avatar image theeldar commented ·

Relatively simple. I live in a multi-apartment house. A structural change of the electricity connection with the payment meters would force a modernization to the current technical standard. Since the technology is so old, a simple addition is not possible. However, the owners of the building do not agree to an update of the system and I cannot cover the costs of about 20,000 euros for the update on my own.

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