question

Paul B avatar image
Paul B asked

Generator Sync Issue

Has anyone noticed that the generator does not sync or keeps loosing sync if.

AC low Disconnect is too close to the generator running AC voltage especially during the day with Grid Tie solar connected.

Currently the Generator is running at 227 Volts AC 49hz and seems stable at that setting

Now it seems that If I move the AC low disconnect up to 215 or 220 volts then I find that I seem to be getting no gen sync at startup or Generator sync drop outs when the generator is running. yet the voltages dont show any issues in the VRM

I am wanting to move these as close a I can to the running voltage is 215 or 220 so that I dont get a drop in the AC grid connected solar when the Generator turns off.


NOW if I turn week AC on then I do not seem to get no sync issue, however my charger output drops by 1/3rd so I dont want the week AC on


am using the Assistant PV Inverter support for control the Hz cut off and that works well


I am still investigating this, so if anyone has seen it please advise and add your comments

3 x Multiplus 48/5000 Fw 481 operating in Parrallel 15Kw battery bank is 28Kw Lifep04

CCGX FW 2.65


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MultiPlus Quattro Inverter Charger
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2 Answers
Alexandra avatar image
Alexandra answered ·

@Paul B

We have seen even on decent brand generators a harmonic from it that causes an issue with synchronization. So maybe check the AVR is ok?

The clue to the issue is when you enabled weak ac and have the wide frequency range checked.

A work around is speeding up the generator motor a bit running with a higher Hz, or loading up the generator before connecting to the Victron helps with this.

Second clue may be that there is an interaction with the AC PV (also frequency related- is your ac pv a frequency shifted one?) There may be a bit of feedback through the multi to the generator so its messing with the output of the AVR. Running at a higher Hz from the generator may also help with that by throttling the PV a bit.

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Paul B avatar image Paul B commented ·

Interesting thoughts THANKS,

I have also notice that if I have Hi PV say 12 KV max charge occuring 10KV (200amps) and the gen is then started

I see the charging drop to zero and I also see a -4000 AC export. for a few seconds. then it corrects itsself.


I have grid selected as NONE so a export should really never occur.

Ill try increasing the Generators hz a little bit and see what happens




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Rob Duthie avatar image Rob Duthie commented ·
Hi

Turn off UPS function, this does help.

Regards

Rob D

NZ

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Paul B avatar image Paul B Rob Duthie commented ·

Thanks for the feed back

I ended up turning powerassist off - as I was not using it on this site and that made a big difference to the system dropping sync for no reason and its never dropped since ,

in my case ups on or off made no difference


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Rob Duthie avatar image
Rob Duthie answered ·

Hi

Very Odd, as per Victrons manuals they say to turn off, i don't think have got a handle on these genset issues as there are lots out with gensets dropping out all the time and totally random etc.

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