question

Vangelis Beligiannis avatar image
Vangelis Beligiannis asked

ESS shuts down the ac coupled inverter if one phase is lost in AC in

In three phase ESS systems, when L2 or L3 phases are lost (and L1 is still present) the AC coupled Fronius inverter on AC out will not operate and an error 105 is dispalyed. If L1 phase is lost and the others are present the problem does not appear.

This means that the ESS system will not charge the batteries in a power failure of the grid so the system is useless....

I have contacted Victron support since 2022 but nothing has been done. Another member of the community verified the problem and said that Victron replied that it is not their priority to fix the problem. Fronius support on the other hand has reported immediately that this has to be handled by VIctron.

Please give some attention to the matter. There are many of my clients that complain an say that they paid for a system that is not working when necessary...

ESS
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3 Answers
Alexandra avatar image
Alexandra answered ·

@Vangelis Beligiannis

And I know several three phase systems that don't have the issue but similar circumstances.

Loss of one or two phases... micro grid kicks in and everything is fine.

Does the 105 clear of the the fronius is switched off then switched on again?

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Daniël Boekel (Victron Energy Staff) avatar image
Daniël Boekel (Victron Energy Staff) answered ·

Hi all,


what happens is that as long as L1 is (partly) present, the Multi's will try to be ready to connect to grid as soon as it's within the margins.

To be ready, the PV inverter(s) are switched off by raising the frequency every couple of seconds (because synchronizing to normal grid frequency will cause the PV to run un-throttled, possibly causing AC and DC overvoltage)

One of the ways to go around this:

-use a grid quality relay to completely switch off grid when not all phases are good

-(not 100% sure this works) use assistants to ignore grid (possibly triggered by an external grid quality relay)

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Vangelis Beligiannis avatar image
Vangelis Beligiannis answered ·

No it does not recover with a restart. The issues has to do with something regarding the L1 phase .

Why does it happen when L1 is present and why does it not happen when L1 is not present?

Normally the inverter will open the AC in relay as soon as any phase i lost. But this is probably not the case. L1 is the primary phase and probably a mechanism or filter still uses it and mixes up the Fronius inverter. I have installed 6 systems and it happens in all 6!!!!

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