Flicker and wild voltage and frequency variation of Quattro output when operating with generator

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Chris asked Jan 22, '19

Flicker and wild voltage and frequency variation of Quattro output when operating with generator

Hi

We are experiencing this same issue on multiple sites. Both with AC connected PV and sites with charge controllers.

Quattro 5kw off grid system. 50hz 230v

When the backup generator is operating, the output from the Quattro varies wildly and also it appears so does the load placed on the generator - to charge the batteries (from the VRM portal data)

This is backed up up by the display on the generator (Hyundai DHY6000) which shows frequency.

Frequency output from the quattro is so unstable it cases the Fronius PV inverter to cut out and also the washine machine on site to go into fault. Also voltage is all over the place, and all this causes lighting flicker too.

UPS function setting is off

I have tried lowering the shore power setting.

I have tried lowering the output voltage slightly on the Quattro. (output on the genny when unloaded is 230v)

Dynamic current limiter on or off makes no difference.

Accept wide frequency range is on.

I am assuming that the quattros inverter attempts to track the AC input frequency and doesnt do a great job of it.

If powerassist was disabled - would this prevent the inverter output from trying to track whats happening with the AC input ?

Any ideas?

Thanks

Chris

MultiPlus Quattro Inverter Charger Generator offgrid frequency

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wkirby ♦♦ commented · Jan 22, 2019 at 09:23 PM

How much PV power do you have? It is on AC-OUT of Quattro?
If it PV is on Quattro output, how is it working without generator?

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Answer 1 · 2019-02-03T06:48:38Z

Paul B answered · Feb 03, 2019 at 06:48 AM

These are some ideas and I am no expert in this area AT ALL

Once the generator is running and the inverter is in bypass mode then its got nothing to do with frequency control, this is all done by the generator or the Grid Tie inverter (depending on settings)

have you got export power turned on as the generator would not like this ay all, so disable this in the inverter.

as you are running a grid Tie inverter then the battery bank SIZE must be equal to or greater then the PV panel array and frequency control would need to be configured so that the PV inverter can be told to turnoff when the loads and charging are less than whats needed. this I believe is all controlled in the ESS assistance's thats usually setup in the Quattro by the installer

does it all work well if all the solar is turned off ie at night

you can also run through all the suggested steps in the MultiPlus generator FAQ.

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Answer 2 · 2021-06-21T04:10:24Z

malbal answered · Jun 21, 2021 at 04:10 AM

I have also got the same issue. Off grid house. 7.5kW solar array. 20kWh 48Vdc BAE VRLA battery bank. 6kVA Kubota low boy diesel generator. MPPT and Quattro, with BMV and colour control GX.

When the diesel generator is running, either at night or at day, the voltage and frequency fluctuates so much that the lights flicker. The generator load also is ranging from AC current input rating to half of that, even unloading completely for short periods.

I have tried changing the Quattro settings up and down, for AC1 input, inverter output voltage, dynamic current limiter but nothing seems to help.

I will try powerassist off and UPS off and see what happens.

Does Victron have an answer to this yet or should I keep experimenting?

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ryan-coetzee commented · Jun 21, 2021 at 11:06 AM

I am having the same issue. 3 x 8KVA quattros setup for 3 phase with 40kWh Revov battery. 10KW Fronius inverter and generator is cummins 100KVA (highly oversized but it was what was there already). Fronius is turned off when generator is running.

Batteries start charging fine at 140A with no flickering but after about 10 minutes the inverters start making a pulsing humming sound and the lights flicker until the inverters throttle their charge current. Manually throttling charge current down via DVCC helps a little but the large fluctuations in voltage and freq still occur.

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JohnC ♦ commented · Jun 21, 2021 at 11:51 AM

Hi @malbal

I suffer this too with a Multiplus, and have always blamed the generator. But I don't really know why it happens..

Ticking 'Weak AC' smoothes it right down for me, and you could try that too. Not really a great solution, but I'm interested in how you go in your efforts to help pinpoint whatever the cause is.

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Answer 3 · 2021-09-06T23:26:17Z

Chris answered · Sep 06, 2021 at 11:26 PM

Ive really wanted to put an ociliscope on the AC output to see the quality of the waveform. I strongly suspect it is down to a mishapen AC waveform.

Tried all sorts of options, and little helps. Also what doesnt help either is most generators operate at a higher AC frequency when off load, so then when they are loaded up, the frequency drops.

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