[time-nuts] Line Frequeny Stablity

[Andy]

Several years ago (c. 1980) I remember an occasion when the local utility
slipped about 20-25 minutes of effective 'time' over the course of one
night.

I didn't know much about power grids then, except that they existed, and
contributed to certain power blackouts.  But what happened was that the
local utility had gotten disconnected from the rest of the northeast USA
grid, and free-ran overnight at a significantly offset frequency.  I think
it would have been running at around 57 Hz or lower.

Andy