Combining two SMA SB1200TL inverters in a system design?

[Blueflash]

My boss who designs all our systems has had me construct AC work consisting of two SMA 1200TL inverters combined. Meaning, own circuit until the finally meet at the 3 phase meter terminals.
I personally thought this was incorrect and they should be totally independant of each other until the bus bar. This system has developed a grid fault (one inverter down) that I must look at on Monday, but feel the design is to blame and there may be damage to one or both inverters?
Does one inverter "see" the other as the Grid, thus create over voltage for exporting power?

Your thoughts please.

 

[Gavin A]

3 phase - I presume you're talking about the tripower 12000TL's then?

shouldn't be any problem with combining them providing the cable is suitably sized to prevent the voltage going too high with the 2 inverters pushing power down it. You'd need to up the cable rating vs the recommendation for just the single inverter though.

The circuit for each inverter would need it's own MCB and isolator at the point the circuit splits though.

I suspect if you've got a grid fault issue developed that the cable has been undersized for carrying the 2 inverters output.