question

wesley-corbet avatar image
wesley-corbet asked

Redundancy in a 3 Phase Parallel system

Hi

I have been asked by a customer to provide an off-grid system using 6 x Quattro 15000/48 inverters, parallel, 3 phase, connected to a common battery, common AC output and a common gen-set connected to the AC input. He would like redundancy so if one inverter were to fail it only takes out a group of 3 and not all 6. That way he still has 1/2 power to get by with in the event of a single inverter failure. With the typical configuration, this is not possible, however I ask the community, does anyone have any ideas if this can be achieved?

Thanks

Wes Corbet

MultiPlus Quattro Inverter Chargerbattery charging3 phase
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4 Answers
Matthias Lange - DE avatar image
Matthias Lange - DE answered ·

Theoretically that is possible practically you have to reconfigure the system to remove the defective unit.
With the VE.Bus System Configurator you can also just remove one unit. For example 2 on L1, 2 on L2 and only 1 on L3.

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ewalderasmus avatar image
ewalderasmus answered ·

Hi @Wesley Corbet

I am shooting from the hip so if there is a fundamental issue with what I'm saying then please ignore.

Is it not possible to wire the two 3 phase systems in series? Where the second set uses the first set as an AC input? and you use Power Assist to manage the full load?

So if there is a failure on the first 3 phase set, the customer wont notice it (as Set 2 will see it as a mains failure event). You might need a bypass contactor (possibily a normally closed, driven by Set 2) so if set 2 fails mains can be restored while the fault is fixed.

I did a hand drawing but the only pen I had near me was red so it looks shocking, hence why I didn't upload it.

Just an idea. Let me know.

Regards Ewald


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tnt369 answered ·
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wesley-corbet avatar image
wesley-corbet answered ·

Hi All,

Thank you for the answers, all very helpful.

I am leaning towards Matthias's suggestion because of the standard configuration and I was not aware the system could continue to operate with 5 out of 6 inverters with a re-configure.This would not be too bad, considering the low inverter failure rate.

Putting the Quattro's in series is also a solution, just a bit more complex. Thinking at this stage keeping it as simple as it can be. Thanks again for taking the time to post a reply.

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