[time-nuts] A Research Proposal

[Andy Backus]

Historically, and even today, the steady frequency of AC power has been used for timekeeping.  So there may be interest here in the following research proposal:

Within a given power distribution grid, several observers as widely separated geographically as possible, time stamp the first two zero crossings of the power line after each UTC second – over the course of 24 hours (86,400 pairs of data).

Popularly conceived, all the components of a power distribution grid are phase locked – though, of course, power is taken in and out by varying degrees of lead or lag.  Frequency is maintained by a constant balancing act between load and generation.

Typical power distribution grids, however, are sized on a scale of thousands of miles.  “Locking phase,” then, is problematic simply on the basis of the limits of information transmission rate.  Even at c, every 1000 miles takes 5 ms, which represents a third to a quarter of the period of the AC power waveform.

Many interesting phenomena might result from that reality, which suggests a certain constrained flexibility over large distances – almost as if the system is like a large lake of viscous liquid.  When there are local disturbances such as rapid load changes or sudden generation adjustments, for example, it is quite possible harmonic ripples could be propagated through the system.

Such effects could be observed by comparing phase data across significant distances within a distribution grid.

Andy Backus
Bellingham, WA
USA

________________________________
From: time-nuts <time-nuts-bounces at lists.febo.com> on behalf of Thomas D. Erb <tde at electrictime.com>
Sent: Thursday, July 4, 2019 5:23 AM
To: time-nuts at lists.febo.com
Subject: Re: [time-nuts] 60 Hz frequency and phase measurement

We have used line frequency counting for time keeping in the past  it works very well in the USA - EXCEPT in locations with lots of dimmers - theaters in particular chop the AC waveform creating lots of noise and can make the internal timer run fast.  I think at one location we had 5 volts of noise on the mains. TXO chips just always work - so we use them now, or GPS.

I had a recent tour of a power station - the operators had no idea the output was synchronized to a time standard - they just synchronize with the local grid.

For a history of line frequency time keeping, Wikipedia has a good entry.
https://en.wikipedia.org/wiki/Telechron

Though Tesla I believe demonstrated this at the Chicago World's fair.

I have a master in my small museum.
https://electricclock.omeka.net/items/show/12





Thomas D. Erb
p:        508-359-4396
f:        508-359-4482
a:        97 West Street, Medfield, MA 02052 USA
e:         tde at electrictime.com
w:        www.electrictime.com<http://www.electrictime.com>
Tower & Street Clocks Since 1928

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