On 11/27/15 3:06 PM, Eero Aro wrote:
> I have no idea how stable the mains frequency is today.
Several decades ago I spent some time designing power monitoring
equipment. Here's what I learned about the US electric grid:
Usual error is less than 0.02 Hz.
Occasional error 0.03 Hz.
If error is greater than 0.05 Hz the electric grid is in trouble -- time
to start your backup generator.
These numbers are confirmed by Figure 2.4 on page 7 of this document:
-- John Chester