Hi

Back in the 1960’s what you describe is pretty much “how it was done”. We figured out that the local power company “lined things up” between 4 and 5PM each day. Tune into WWV and you could watch them bring your wall clock (hooked to AC power) into line with WWV. Indeed seconds / ten’s of seconds sort of corrections occurred. We suspected there must be a reason. One of the gang went on a tour of the power plant and asked them why? The answer turned out to be that they connected back up to the grid at 5 PM. Mid day, they generated the power locally. Just like us, they had a radio that listened to WWV.

These days, if you are hooked to one of the grids, drifting seconds is pretty unusual. Everybody needs to stay “in phase” and that (since the  late 1980’s) usually goes back to GPS (at least in the US and Canada). If you are “off grid” then I suspect you are right back to the 1960’s approach, at least in some cases.

Do the corrections get logged? I suspect they do indeed get documented in some way. It could easily be a paper form sitting in an office somewhere. Find out the phone number for that office and you probably could get the after the fact info. There also does need to be a “how many microseconds of phase shift” sort of number. It would be specific to this or that source feeding the grid. Without that, you would have a very hard time controlling things. No idea how to get at that number or if it actually would be of any use.

Bob

See this web page:

https://www.nationalgrideso.com/data-portal/system-frequency-data

for 1s resolution stats for the UK.  As much data as you could possibly want!  Here's another site that also tracks Europe - lots of cross-border power links.

https://gridradar.net/en/mains-frequency

Grid locking is another thing that could be disrupted by GNSS outage.

-----Original Message-----
From: Bob Camp via time-nuts time-nuts@lists.febo.com
Sent: Friday, March 22, 2024 5:05 PM
To: Discussion of precise time and frequency measurement time-nuts@lists.febo.com
Cc: Bob Camp kb8tq@n1k.org
Subject: [time-nuts] Re: Power line timing -- setting a clock

Hi

Back in the 1960’s what you describe is pretty much “how it was done”. We figured out that the local power company “lined things up” between 4 and 5PM each day. Tune into WWV and you could watch them bring your wall clock (hooked to AC power) into line with WWV. Indeed seconds / ten’s of seconds sort of corrections occurred. We suspected there must be a reason. One of the gang went on a tour of the power plant and asked them why? The answer turned out to be that they connected back up to the grid at 5 PM. Mid day, they generated the power locally. Just like us, they had a radio that listened to WWV.

These days, if you are hooked to one of the grids, drifting seconds is pretty unusual. Everybody needs to stay “in phase” and that (since the  late 1980’s) usually goes back to GPS (at least in the US and Canada). If you are “off grid” then I suspect you are right back to the 1960’s approach, at least in some cases.

Do the corrections get logged? I suspect they do indeed get documented in some way. It could easily be a paper form sitting in an office somewhere. Find out the phone number for that office and you probably could get the after the fact info. There also does need to be a “how many microseconds of phase shift” sort of number. It would be specific to this or that source feeding the grid. Without that, you would have a very hard time controlling things. No idea how to get at that number or if it actually would be of any use.

Bob

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Back in the 1970's I installed Westinghouse power plants
in the US and around the world.   On the control panel
there was a sort of clock that showed the difference between
the AC produced by the plant and some reference, could be
WWV or a crystal, I don't remember.

The "clock" had only one pointer and would advance clockwise if
the plant was running fast and it would move counter-clockwise
if the plant was running slow.   If the pointer went around more
than one turn then you did not really know where you were.

In the US the clocks were not used because the frequency was
determined by the regional dispatcher.

Overseas the clocks were ignored by the operators because no
one used AC driven clocks.   People were just happy to have
power and did not care about the frequency.   If the voltage
was reasonably close the the frequency was more or less correct
that was much better than the alternative, no power.

On 3/21/2024 6:13 AM, Hal Murray via time-nuts wrote:

People were happy to have power. Though as was stated before, very out-of-sync- will destroy a generator. There are many ways to successfully carry out the operation.
To add insult to injury, phase, voltage & freq must be very close. Otherwise bang. Generally when the operator closes the breaker, fire erupts. Otherwise the whole thing tears itself apart. Maybe another down the line.

Ciao baby, catch you on the flip side
73 de W3AB/GEOAFA9GB

WA2LSI, KE6RJW, W6B, W7B, AAR9AG
http://www.w3ab.org

Summers fly by,winters always walk.

On Friday, March 22, 2024 at 04:56:32 PM PDT, Peter Reilley via time-nuts <time-nuts@lists.febo.com> wrote:  

Back in the 1970's I installed Westinghouse power plants
in the US and around the world.   On the control panel
there was a sort of clock that showed the difference between
the AC produced by the plant and some reference, could be
WWV or a crystal, I don't remember.

The "clock" had only one pointer and would advance clockwise if
the plant was running fast and it would move counter-clockwise
if the plant was running slow.   If the pointer went around more
than one turn then you did not really know where you were.

In the US the clocks were not used because the frequency was
determined by the regional dispatcher.

Overseas the clocks were ignored by the operators because no
one used AC driven clocks.   People were just happy to have
power and did not care about the frequency.   If the voltage
was reasonably close the the frequency was more or less correct
that was much better than the alternative, no power.

On 3/21/2024 6:13 AM, Hal Murray via time-nuts wrote:

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To unsubscribe send an email to time-nuts-leave@lists.febo.com

Hi Bob,

There are some 3 letter agencies that use power frequency variations to
help determine when video or audio is recorded. Tom Scott did a Youtube
video about it here https://youtu.be/e0elNU0iOMY ..

There are a few frequency disturbance recorders out there; one is called
GridEye. IEEE has a paper or two on FNET. The Federal Power Act in 2009
required automatic time error correction (ATEC) so people with older alarm
clocks without an oscillator can wake up on-time.

It's fun stuff. I'm glad someone brought it up so I can geek out for a
minute :)

-Clive

On Fri, Mar 22, 2024 at 2:47 PM Bob Camp via time-nuts <
time-nuts@lists.febo.com> wrote:

In the plants that I installed they had a synchroscope and two light bulbs.
The both performed the same function.
You normally used the synchroscope because it was more accurate.
The light bulbs there sort of an anachronistic backup.   In the real
old days they used the light bulbs the synchronize the generator.
There were two bulbs connected in series because the voltage
sensing transformers output 120 volts.   When the system and
the generator were in phase the bulbs would go out.   When they
were out of phase the result was 240 volts at the bulbs thus you
needed two in series.   Yes there are 240 bulbs but 120 volt
bulbs are cheap and available.

On 3/22/2024 6:46 PM, GEO Badger via time-nuts wrote: