What is the Fault current and overload capacity of Victron inverters?

Hi, All

We are designing some off grid system using quattro 10 kVa. However, client need to know

1. Rated Maximum Expected Fault Current (Duration XX Sec) Contribution per Line per Inverter (A)

2. Overload capacity with period. like 150% overload during (xx min) etc

I donot know where I can find them in datasheet and manual

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Johannes Boonstra (Victron Energy Staff) answered ·

Hello, Fault current is the current to a defective device to ground i assume?, for the inverter that's not different then the normal (overload) power. So the rating is equal there.

If you mean short circuit power, that's limited by the DC circuitry as a low level battery can't supply as much energy as a full one, but its maximal 2 x Inom for 0,5s.

as far as overload, that's also limited as the peak power is and beside this software controlled.

at 20C deg its

2 x Inom - 0,5Sec ( when the load is so high the inverter isn't able to maintain AC voltage as in short circuit situations)

2 x Inom - 2 min when the Ac voltage is as it should be

1,3 x Inom - 30min

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Hi Johannes,

All OK with this answer but what is missing from the specification sheet is the Inom. In the spec sheets, the power output is the same for differing system voltages. For example the 10kVA Quattro spec sheet nominated max power as 20,000W for both system voltages. For the 230 Volt system is Inom = 43.47A? and for the 120Volt system is Inom = 83.33A?.

This is important to understand in relation to protection co ordination. For example a 16A MCCB type C breaker will need about 160A to trip.

So in fault conditions when system voltage is not so relevant is the current from the 10kVA Quattro 166A or 87A?

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Thanks Klim:

However, this is only half of answer. Client wants to know fault current contributed from inverter, for example like 100A or sth, because they want to set their protection breaker to trip 400ms at fault 100A.

This is such a frustrating situation. There are a large number of unit sales pending the answer to this question.

The closest information we can find is on the last page of the G59/3-1 Certificate here:

And yet it is extremely unclear with minimal information.

I'm guessing the only way we're really going to get the information is to prove it our selves by potentially blowing a couple of units up?

Is there anyone who can help please?

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I'm struggling with a very similar question. How does a MultiPlus/Quattro behave into a hard short, and hence how long will it take a breaker to trip? If I use a Curve C or D breaker, will I toast the inverter before the breaker trips? As long as the grid is connected, I know I have a kiloamp or more to make the breaker trip quickly, but what is the situation in island mode? (Like @stretcho, I'm reluctant to experiment, in case I blow up my installation.)

To be confident that my installation will survive a sudden hard short in island mode, should I install a special kind of breaker?

Hi @Evonet, The inverter itself has built in output short circuit protection - so while not recommended to test it yourself, it has been designed into the unit by Victron, then tested and approved by a 3rd party. A short circuit on output will be detected, and the unit will shut itself down before damage to the inverter.

You can see it listed in the protection section of the product data sheets.

Breakers are of course also recommended to protect all circuits on the output, but not for the protection of the inverter itself.

Guy Stewart (Victron Community Manager) ♦♦

Thank you, Guy. If I want to make sure that a short on a branch circuit disconnects that branch only, and leaves the inverter operating for the rest of the installation, what kind of breakers should I be using?

Really really hard to say, short circuits are pretty intense, and I would want to test that once I had done my best to size the various circuits and loaded the system to a 'normal' level.

It would depend on the size of the inverter and the size of the load on the other circuits as to whether it overloaded the inverter (which would then restart automatically in 30 seconds), or just trip the breaker. Sorry to say there is no way to be sure. Size your breakers as close as possible to the load (and of course using wire well in excess of the rated capacity).

Many smaller breakers, on smaller circuits, with smaller loads will deal with it better than a few large breakers on a few large circuits and a few large loads.

Guy Stewart (Victron Community Manager) ♦♦

Thank you, Guy. Clearly, it isn't straightforward - but it's good to know the inverter will protect itself in this situation.

It does rather undermine the idea that a system with a Victron inverter will provide a guarantee against supply interruption.

I'm aware there are various kinds of electronic circuit breaker specifically for inverter systems (eg Type Z), but they're hard to find and expensive, and it sounds as though the benefit of using them would be marginal.