Correction and apology:
I said: ( if one machine is
0.01Hz fast or slow, then instability can occur in less than a second. )

That is wrong. 3.6 degrees/second implies about 25 seconds to steady state
instability. This is , of course, too simplistic as such a sustained
frequency difference will not occur - either the errant machine is pulled
back into synchronism or has been tripped out -hopefully without bringing
the whole system down.

This also applies to incoming machines- either they get in line or get
kicked out-now!.
--

Don Kelly @shawcross.ca
remove the X to answer
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