I’m not sure I understand how this works unless you split off loads into a subpanel that is fed by a UPS which is fed by solar panels, and also isolated from your utility connected electrical service.

As far as I understand it, you can’t have power generated by solar panels feeding loads in your grid-connected panel without backfeeding the grid, same deal as a generator backfeeding a grid-connected panel. You have to kill the MCB or service disconnect to prevent backfeeding.

If you have links with info on how this work (one-line diagram would be extremely useful) I’d be curious. I sell and run commercial electrical work, FWIW. I’ve done zero solar jobs so my understanding could definitely be wrong!