Designed a system with 3x 15kVA Quattros in 3-phase config. Largest I have done so far (prev 3x 5kVA Quattros where this was not an issue).
System works perfectly, but I always do black-start tests in the event DC runs completely flat, and each time I attempt to start up via the AC side, the inverters detect AC1, open the AC1 relay, and then presumably the inrush is so large on this system it trips the 3phase Type C 80A MCB protecting the system, and the Quattros obviously then have no power.
The issue I guess is that the inrush is so massive and seems like a dead short that the MCB trips - since all 3 inverters are starting up at the same time (unlike DC when they are switched on one-by-one).
(3x BYD LVL's on this system, but that won't matter if they are all discharged).
Any ideas on how to overcome it?
- I feel like alternate-curve (i.e. Type D) MCB's are not going to be a solution but maybe worth a try
- Adding an alternate push button connected to 3x power resistors for startup, in parallel to the MCB, might be a good idea... push the button, charge the caps, and then flip the MCB for example...
- Add an alternate DC power source, but can't be panels due to location - so MPPT is out
Clearly this is not a likely scenario, but being without a solution creates a significant risk
Thoughts much appreciated, thank you!
