[time-nuts] Mains as time-reference

Mark Spencer mspencer12345 at yahoo.ca
Thu Dec 30 02:49:21 UTC 2010


Page 2 of this document gives some insight as to the changes of the mains frequency that may be seen in the USA.


http://www.nerc.com/docs/docs/oc/oc_16-17Mar05_highlights.pdf

This presentation also contains some related info.

http://www.nerc.com/fileUploads/File/Training/Webinar-Generator-Frequency-Response.050509.pdf



--- On Wed, 12/29/10, Javier Herrero <jherrero at hvsistemas.es> wrote:

> From: Javier Herrero <jherrero at hvsistemas.es>
> Subject: Re: [time-nuts] Mains as time-reference
> To: time-nuts at febo.com
> Received: Wednesday, December 29, 2010, 8:17 PM
> One of your references links to a
> nice real time graph for UK :)
> 
> http://www.nationalgrid.com/uk/Electricity/Data/Realtime/Frequency/Freq60.htm
> 
> I've looked to see if Red Eléctrica de España, the
> equivalent organisation here, provides same data... but
> nothing interesting to time-nuts, only electrical production
> and demand graphs (and a very politically correct graph of
> corresponding estimates of CO2 emissions).
> 
> Regards,
> 
> Javier
> 
> El 29/12/2010 20:01, Tom Van Baak escribió:
> > Magnus,
> > 
> > See fellow mains measurement men:
> > 
> > http://www.xs4all.nl/~rjoris/gridfrequency.html
> > http://www.vf.utwente.nl/~ptdeboer/misc/mains.html
> > http://www.leapsecond.com/pages/mains/
> > 
> > /tvb
> > 
> > ----- Original Message ----- From: "Magnus Danielson"
> <magnus at rubidium.dyndns.org>
> > To: "Discussion of precise time and frequency
> measurement" <time-nuts at febo.com>
> > Sent: Wednesday, December 29, 2010 10:45 AM
> > Subject: [time-nuts] Mains as time-reference
> > 
> > 
> >> Fellow time-nuts,
> >> 
> >> Just for fun I have been looking at the mains as a
> time-reference.
> >> 
> >> I've used an OSA 8600 as reference and divided
> down to PPS by a TADD-2. While not absolute time reference,
> it is way quieter than the mains so I think it is good
> enough to have some fun at least. Just to illustrate the
> issue.
> >> 
> >> I use a HP5335A to measure the time from PPS to
> rising edge of 50 Hz as being accessible through a
> transformer.
> >> 
> >> The ADEV has a peak at 30 s measuring 2,3E-4 and
> another at 6000 s measuring 4,3E-4.
> >> 
> >> The phase changes over -0.11923 to +10,979 so a
> time difference peak-to-peak of 11,098 seconds.
> >> 
> >> While I could refine my measurements to ensure
> trigger jitter is not causing any major issues, the ADEV
> slope from 1 s is rising rather than lowering, so it rather
> seems like source behaviour dominates.
> >> 
> >> While this attempt is a hack, I hope it inspires
> people to fiddle around a little. :)
> >> 
> >> Cheers,
> >> Magnus
> > 
> > 
> > 
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> > 
> 
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