Venus OS 3.31 - ESS settings of AC current limits do not show (ESS Assistant 018C is active)

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hominidae asked Apr 27, '24

Venus OS 3.31 - ESS settings of AC current limits do not show (ESS Assistant 018C is active)

...according to changelog of Venus OS v3.30-10 and this https://www.victronenergy.com/live/drafts:dynamic_ess#qwhy_does_the_system_exceed_the_configured_power ...the settings should show up in my GX.

I have an EM540 as grid meter, GX is running v3.31 and a 3ph-MP2 setup is running v510 and ESS assistant 018C.

So what's the deal here?

@Dirk-Jan Faber (Victron Energy) ...there is a new law introduced in germany, for all grid connected battery systems, that are capable of drawing above 4.2kW from the grid. The system needs to be enabled to be externally triggered by the DSO to reduce input power to 4.2kW.

See here: https://www.bundesnetzagentur.de/DE/Fachthemen/ElektrizitaetundGas/Aktuelles_enwg/14a/start.html

This is true for all new installations starting from Jan 1st 2024.
The Operator/Owner is required to enable the external control by the DSO

Luckily the DSO currently has no means of sending the trigger (yet), but will be soon as smart meter rollout will increase.

Most likely it will be implemented by a control box and a NO/NC potential free switch/relay...but for some installations another method, probably via IEC61850 and scheduled charging could be chosen, too.

Something to take into account for (D)ESS systems in Germany....

ESS Venus OS dess external control germany

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Dirk-Jan Faber (Victron Energy) ♦ commented · Apr 28 at 02:40 PM

What is the vrm id of your system?

Regarding the regulations is my first hunch that it is part of the the grid code and therefor implemented on the inverter/charger level instead of something that Dynamic ESS has to deal with. But I will check with some of my colleagues that know more about that.

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hominidae Dirk-Jan Faber (Victron Energy) ♦ commented · Apr 28 at 06:03 PM

@Dirk-Jan Faber (Victron Energy)

My VRM id is 48e7dadf2705 - I am not using DESS, as I do have two tariffs where only one of the two is dynamic and the installation iss a cascading setup, meter wise.

The new regulation is according to §14a EnWG in Germany.

And yes, there might be two options to satusfy these..one could be from the inverter side, externally controlled by the grid operator or the second option could be via ESS.

Actually the owner/operator of the system is the one to decide.

Since the controls are basically there in (D)ESS, I'd gather that the option with employing the ESS comes naturally.

The "problem" is, that is is required for new installations as of Jan. 1st 2024 and the owner/operators only option in order to obey the law/being able to switch the system on, is to request the "smart meter and controllable function" from the DSO.

Since my system is operating since 2022, I am not affected, but other are and will be.

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hominidae answered · Apr 30 at 03:29 PM

OK, here's the solution/answer...thanks to @Dirk-Jan Faber (Victron Energy) for the remote support :

The setting is not related/dependent on DESS (whether it is enabled or not)

In the ESS settings, under "peak shaving", you'll have to enable "always" instead of "unless minSoC is reached". Only then, the settings for import/export current limits will appear.

...this wasn't clear to me, based on the release notes or the documentation given.

However I still don't see why the limits won't be needed to be applied if peak shaving would be limited for situations where SOC is above minSOC value.

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Answer 1 · 2024-04-28T05:32:47Z

nickdb answered · Apr 28 at 05:32 AM

Do you mean 3.31? 3.11 is an old version and would not support DESS at all.

Those were features introduced for DESS, not ESS, and would only be on systems using DESS, with the current versions of Venus OS. It is not part of the assistant.

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hominidae commented · Apr 28 at 10:48 AM

...yes, sorry, it's fw 3.31 on my GX...I added a screenshot and corrected the typo.

So this would only show up in my GX under the ESS settings, when DESS is enabled in VRM, you say? DESS is not usable for me, as I have a caskading setup with two tariffs, where only one of them is dynamic.

However, with the new legislation in Germany, new systems will need that kind of setting (and switchable externally by the DSO), with or without DESS regardless.

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nickdb ♦♦ hominidae commented · Apr 28 at 04:26 PM

DJF has replied to you. I am sure he can answer your questions since he is intimately acquainted with this project.

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Answer 2 · 2024-04-28T18:18:40Z

Matthias Lange - DE answered · Apr 28 at 06:18 PM

The easiest way to implement the new regulation is to use the assistant for input current limit and a AUX input.

If the signal comes from the DSO it closes the AUX input and you limit the AC input current to 6A per phase, done.

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