[time-nuts] 60 Hz frequency and phase measurement

[Andy Backus]

For anyone interested, here are the data from the Western Interconnection for June, 2019.  These are essentially the integral of frequency deviations (from 60.00000 Hz) wrt time.  That's the TE, for those in the business.  It is a zipped file.  When uncrunched (WinZip works) it will give a file suitable for Excel (you might have to rename the extension) -- that is 4 MB.

Col A
year in two digits (UTC)

Col B
day of the year (UTC)

Col C
hour (UTC)

Col D
minute (UTC)

Col E
second (UTC)

Col F
Time Error in cycles (wrt industry zero)

Col G
delta phase in % of a cycle from the UTC second (higher = grid upward zero crossing sooner before second)

Col H
TE calculated with whole cycles only

Col I
time in hours since row one (00:00:00 on June 1, 2019 UTC)

Col J
TE calculated including partial cycle

Graph = TE vs hours

Andy Backus
Bellingham, WA

BTW -- I have comparable data for every UTC minute over the last the two years
Also -- tnx to Tom vb for crunching my Excel file

________________________________
From: time-nuts <time-nuts-bounces at lists.febo.com> on behalf of Paul Theodoropoulos via time-nuts <time-nuts at lists.febo.com>
Sent: Wednesday, July 3, 2019 11:06 AM
To: Discussion of precise time and frequency measurement
Cc: Paul Theodoropoulos
Subject: Re: [time-nuts] 60 Hz frequency and phase measurement

This stuff is fascinating to a time-nut-level:Novice such as myself.
While falling down the rabbit-hole searching on all the various bits of
the info below, I ran across this - not sure if you're aware of it, or
if it's old news, but it seems at least peripherally interesting:

http://fnetpublic.utk.edu


On 7/3/19 08:56, Tom Van Baak wrote:
> Bob,
>
> Several of us do long-term measurement of mains frequency. We tend to
> time-stamp cycles and then compute period or frequency, rather than
> measuring frequency or period directly. Traditional counters in gated
> frequency or time interval mode have dead time and this will skew
> results.
>
> In my case I just run a 5 VAC wall-wart through a 10k resistor
> directly to the input pin of a PIC. No scaling, no filtering, no opto,
> no ZCD, no nothing. If I measure every cycle I get 155 million samples
> per month. If I extract one cycle each second (decimate by 60) it's
> only 2.5 million samples a month. Many months there is not a single
> glitch in the data in spite of all the FUD about power line noise.
> Once in a while a month contains an extra or missing sample but the
> beauty of timestamp data is that this can be detected and repaired as
> part of data processing with no loss of phase.
>
> Here's a page where Kevin (in New Mexico) and I (in Seattle) both used
> picPET's to measure mains for a few days and then we compared the
> results. Although thousands of miles apart, we're both on the same
> grid so the agreement was astonishing. It was milliseconds in time and
> ADEV down to e-8 over a day:
>
> http://leapsecond.com/pages/mains-cv/
>
> See also: http://leapsecond.com/pic/mains-adev-mdev-gnuplot-g4.png
>
> /tvb
>
>
> On 7/2/2019 10:09 PM, Bob Albert via time-nuts wrote:
>>   I have tried to measure the power line frequency with spotty
>> success.  My best results came from a period measurement, as many
>> periods as the counter can accumulate.  Due to noise, one is never
>> sure at quite what point the source is measured.  Perhaps a brick
>> wall filter would clean it up for a more reliable measurement.
>> Of course, at 60 Hz the period is 16-2/3 milliseconds.  So the
>> counter should properly show a 1 followed by a row of 6s, with the
>> last digit bouncing between 6 and 7 most of the time.
>> If there is a filter used, it will not only remove noise but also
>> short term variations.  But generatlly speaking you don't want to
>> measure those, unless you are trying to evaluate a rotary generator.
>> Getting this reading can be a challenge.
>>      On Tuesday, July 2, 2019, 10:01:03 PM PDT, jimlux
>> <jimlux at earthlink.net> wrote:
>>     On 7/2/19 4:09 PM, Dana Whitlow wrote:
>>> I've always noted that casual attempts to pick up 60 Hz with small
>>> antennas
>>> etc see more harmonics and other trash than actual line frequency.
>>> But if
>>> you're in an office environment, why not plug something in? It's
>>> quite easy
>>> to build a simple passive diode clipper/filter that will plug into a
>>> wall
>>> outlet and
>>> which will provide a sort of soft (but clean) squarewave at a
>>> voltage level
>>> convenient for lab instruments and with good protection against big
>>> spikes
>>> and
>>> other trash riding on the line.
>>
>> Safety approvals are one obstacle (of course one could use a AC wall
>> wart).
>>
>> Actually, it's because someone asked me about a science experiment where
>> you'd place them in a neighborhood outdoors.
>>
>>
>>
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>
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--
Paul Theodoropoulos
www.anastrophe.com<http://www.anastrophe.com>

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