3ph 240V 3W Inverter to replace a Solectria PVI 75kW

[solarken]

Has anyone dealt with replacing an old failed 3ph Solectria PVI 75kW Inverter with a 600V array, DC combiners, etc and 240V 3-Wire delta output wiring? I'm trying to think of an option besides reconfiguring the array, adding a transformer, and redoing a lot of wiring. There doesn't seem to be a lot of 240V delta inverters out there. Would appreciate any ideas.

 

[electrofelon]

I'm not up on 240 delta inverter availability, but is using 3 single phase an option? Doesn't someone make a 25kw 240 single phase inverter . How many strings y'got?

 

[Zee]

Have spent hours researching this. Every time it comes down to triplets of single phase 240VAC resi inverters. SMA in particular.
Maybe Fronius for some larger sizes. 12, 15, 20 kW i think.
(Although now SMA only has battery ready inverters for residentail.......for more $$$. )

INV #1 on AB
INV #2 on BC
INV #3 on AC
repeat as needed

 

[Zee]

The INV AC output Amps don't add up simply, as you likely know. Something about sq root of 3...... embarrassed to have forgotten.
The total is less than a noob would expect.

 

[Zee]

As of 2 years ago, every inverter over residential size was 480 VAC ..........or at least defintely NOT 240 VAC (1 or 3 ph).

 

[Zee]

I got a Q in return: must I balance three inverters across teh three phases, or can I use 2 or 4 or 5 inverters? (not 3 not 6)

 

[electrofelon]

I got a Q in return: must I balance three inverters across teh three phases, or can I use 2 or 4 or 5 inverters? (not 3 not 6)

Nothing prohibiting uneven balancing/ non multiples of 3 in the NEC, POCO may dictate tho.

 

[Zee]

Great, will be doing similar with Enphase soon. New system though.

 

[solarken]

It looks like Solis makes a 30kW 3ph inverter that can be programmed to be compatible with 240V delta high leg. Anyone have any experience with it? I believe it is model S6.

 

[solarken]

I'm not up on 240 delta inverter availability, but is using 3 single phase an option? Doesn't someone make a 25kw 240 single phase inverter . How many strings y'got?

24 strings of 255W modules. I don't have experience with individual single phase inverters for 3phase except Schneider XW Pro Hybrid inverter which has the capability to stack in 3-phase arrangement. Most utilities on our area require all solar inverters connect to grid to cease operation on loss of phase, so I am hesitant to use single phase inverters unless they have built in ability to communicate together on loss of phase?