Europe, 3 phase, 3x inverter balancing question

[no112358]

Hello

This is my first post here. I would like to state that I'm from Europe, just so there's no confusion since there's differences in electrical stuff.

I'm thinking of building a 3 phase system with 3x inverters, batteries and solar.

My house has three apartments in it and each apartment has single phase electrical loads spread over the three phases, example:

apartment 1:
electric stove L1,
water heater L2,
dryer L3,

apartment 2:
water heater L1,
dryer L2,
electric stove L3

apartment 3:
dryer L1,
electric stove L2,
water heater L3

The loads on the grid can get very unbalanced.

I know using one 3 phase inverter could create balancing problems, some allow up to 50% power difference, but does using 3 separate inverters solve the unbalanced load problem?

I tried to explain it as best as I could.

 

[Shimmy]

Either say you need to size the inverter for the worst-case imbalance, or rely on the utility to cover it.

 

[no112358]

Either say you need to size the inverter for the worst-case imbalance, or rely on the utility to cover it.

I understand that, I was wondering if the 3x inverters would even work in a case like this, because I know the one big 3 phase inverter would have balance problems and error out.

 

[timselectric]

Without knowing which products you are trying to compare. The only answer is, maybe.
If the 3 phase inverter is a high frequency unit. It's just 3 inverters in one case. So, there is no difference.

 

[Shimmy]

Do you have nameplate data for the major equipment? A US dryer uses a lot more power than most European ones as an example.

Are you trying to be off-grid or just save on the electric bill?

 

[no112358]

Do you have nameplate data for the major equipment? A US dryer uses a lot more power than most European ones as an example.

Are you trying to be off-grid or just save on the electric bill?

not gonna go offgrid, I don't have enough space for solar.

I don't know exactly how much power the devices use. 2KW for water heater, 2-5KW for stove top, dryer is 1.5KW I think.

 

[Shimmy]

So if you are staying on grid just use a grid-tied inverter (or string inverter without battery capability) and you are fine. If power goes out it will shut off, but still saves you money.

 

[no112358]

So if you are staying on grid just use a grid-tied inverter (or string inverter without battery capability) and you are fine. If power goes out it will shut off, but still saves you money.

I am trying to create battery backup also.

 

[timselectric]

And the grid takes care of balancing.

 

[Shimmy]

I am trying to create battery backup also.

The economical way to do that with your configuration is to have critical loads panel and a house panel. Give each apartment a circuit or two from the critical loads panel.

Otherwise you are looking at needing a 30kW 3-phase inverter or (3) 10-12kW single phase inverters. US price for that is around $18-20k, plus likely $10k minimum for batteries (plus installation if applicable). The critical loads panel approach could be done for $3-5k all-in with something around a 6-9kW inverter.

 

[shavermcspud]

The Solis RHI 3PH can be used in a 100% unbalanced 3PH situation, we have used those quite a few times in the UK.