jim wrote:
Please, can someone kindly elucidate how a domestic 240V house system maintains a stable voltage when connected to an FIT inverter fed from a pv panel?

One moment it's feeding amps into the local supply, the next it may be extracting them. To get a reversible current flow, there must be a pd (potential difference) between the 2 situations. How does it do this trick? (and avoid flickering lights etc).

Are mirrors involved?

It's all low impedance connections, so you need quite a large current
change to make a noticeable difference in the suply voltage. Anything
other than incandescent light bulbs or very old, non-stabilised power
supplies for TV sets won't really notice less than about a 10% change in
voltage anyway, which should need a current change of 100 amps or moreif
all is in order. As most domestic PV panel sets can't generate more than
about 16A, it's not a problem.

--
Tciao for Now!

John.