I'd assume that the power grid is much more vulnerable than that at least some of the time in some regions. What if due to natural load variations the network

I'd assume that the power grid is much more vulnerable than that at least some of the time in some regions. What if due to natural load variations the network already is close to the capacity reserve (which could be measured by tracking AC phase) when somebody mounts an overload attack? What happens if the attacker generated a (e.g. periodic) pattern of load changes that excites control mechanisms at their resonant frequency? Maybe the book "Blackout" [1] (which I haven't read myself) has more (fictional) details about what can go wrong. [1] https://en.wikipedia.org/wiki/Blackout_(Elsberg_novel) https://en.wikipedia.org/wiki/Blackout_(Elsberg_novel)