I've been wondering about this. What happens when a neighborhood with a lot of grid-connected solar systems gets isolated from the grid by some line fault? it's going to happen sooner or later.
I imagine the solar systems are designed to stop outputting and 'stay dead' if the line voltage goes below a certain value, so they won't continuously try to energize a shorted-out grid.
But what if there's enough solar capacity in an area to completely maintain the local load, and that section of the grid is disconnected from the main system?
Sounds like an interesting problem in chaotic systems control. Will the solar systems all try to 'track' each other? What happens to the line voltage and frequency?
Another aspect of this problem, is what happens when someone reconnects the breakers isolating a solar-driven section of grid to the main grid. The two are going to be out of phase - this can't be a good scenario.
I think the solar system inverters would be the likely losers of that particular conflict.
I have friends in the government regulatory body who deal with this specifically - plus we sponsor scholarships in power engineering,
and have "looked after" PhD students also working on the problems. In a nutshell - it's an absolute MESS !! :-)
1/ Grid connect devices are supposed to be smart enough to drop-off when they detect an outage, and it mostly works.
They now "short" the cables they are working on.
2/ So person A connects his solar panels to the grid - he HAS to go in at say 0.5V GREATER than the supply to "source" energy.
neighbour B now connects - HIS system has to go 1.0V GREATER to become a "source". Person A is now screwed. ETC ETC
The Inverters now keep hopping up / down to try and "win". They are legally allowed to go to 155VAC in Aussie, but Inspections have
found tampered units that go to 275VAC (the max you can modify the Inverter). The system is a mess - and idiots did not think it through.
3/ Most Inverters do manage to "lock" on to system phase OK. It's a design criteria. Apparently, they DON'T need to LOCK on to the
power factor though, but I can't understand why not? I have had it explained, but it got pretty deep :-)
4/ I haven't even started on ALL the problems the switch-mode NOISE is creating !! And how it starts all new skin-effect issues !!
The "ideal" system, as used in Europe etc, is for Solar farms with their own motor-generator / sub-station arrangement.
What we have now is an idiotic knee-jerk "solution" that's ONLY going to get worse ! AND it has bugger all benefit to the problem.
When I get time, I'll post the - base load / peak load / boost stats. Don't get me started :-)