Jeremy wrote:
I'm surprised Vlad is seeing as much as six seconds differential but maybe I don't understand the experiment. I've done measurements of the line frequency here in California and never seen much variation.
When was the earliest time (year) you started looking seriously at the offset/frequency of your grid? (California is part of the [North American] Western Interconnection.)
I have only closely observed the line frequency and offset when I have been living within the Eastern Interconnection. For years and years between the 1960s and the 1980s, it was not unusual to observe offsets of +/- 30 seconds, and +/- 60 seconds was not unheard of. I believe the policy has always been to provide 5.184e6 cycles per 24-hour day, so the + and - offsets had to cancel over a specific 24 hour period.
I then didn't pay any attention to the mains frequency until the late aughties, and I found that things have changed. Now, I rarely see offsets greater than +/- 4 to 6 seconds (very rarely, +/- 15 seconds) -- but it does not follow a gaussian distribution, to my (totally anecdotal) observation. It appears to me (again, completely anecdotally) that it is more often within the lowest 25% or the highest 25% [combined] than it is the middle 50%, indicating a process that is being controlled with a marginally stable loop. (Of course, it *is* being controlled -- with a massively distributed feedback system. So no surprise there.)
Best regards, Charles _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
