On Mon, 26 Aug 2019 20:29:00 +0100, The Natural Philosopher wrote:

This also begs the question, if the frequency dropped below
48.whatever, shouldn't thousands of domestic PV systems say,
ooops, don't like this, and shut down too?.

They did. 1/2GW dropped off the grid.

Isn't that an guesstimated 1/2 GW? As it's embedded in the
distribution and not monitored/metered, all they see is a (slight)
reduction in demand from their forecast. Probably well within the
error bars of that forecast.

I don't think the loss of this embedded capacity is included in the
offical figures for how much power the grid lost on that Friday.

--
Cheers
Dave.