[time-nuts] Re: measuring the mains frequency

[Jeremy Nichols]

If you go to that web site, look at the Table Display, scroll down to
Western Interconnection, and look for number 853. That particular Frequency
Disturbance Recorder is in my home in Santa Rosa, California.

Jeremy



On Wed, Mar 1, 2023 at 5:51 PM Sanjeev Gupta via time-nuts <
time-nuts at lists.febo.com> wrote:

> Alex, you may be looking for https://fnetpublic.utk.edu/index.html
>
> --
> Sanjeev Gupta
> +65 98551208     http://www.linkedin.com/in/ghane
>
>
> On Thu, 2 Mar 2023 at 02:11, Alex Pummer via time-nuts <
> time-nuts at lists.febo.com> wrote:
>
> > Hi Andy, there was a website, which showed the nine freq. error around
> > the whole world in real time, did you see it ?and if yes where it is
> > 73
> > KJ6UNH
> > Alex
> >
> > On 2/28/2023 12:03 AM, Andy Talbot via time-nuts wrote:
> > > I use the CCP module in a 16F628 PIC microcontroller.   Measuring the
> > time
> > > for four cycles of the mains and then calculating its frequency.  My
> > > version gives a resolution of about 0.002Hz, but by changing the number
> > of
> > > cycles, clock frequency etc. this can be tweaked for even higher
> > resolution
> > >
> > > In the UK the frequency variation is allowed to be an absolute maximum
> > of
> > > +/-0.5Hz, beyond which automatic load shedding kicks-in.  This happened
> > on
> > > 9 August 2019 when two near-simultaneous failures occurred on the
> > National
> > > Grid.
> > >
> >
> https://www.ofgem.gov.uk/sites/default/files/docs/2019/09/eso_technical_report_-_final.pdf
> > >
> > >
> > > Andy
> > > www.g4jnt.com
> > >
> > >
> > >
> > > On Tue, 28 Feb 2023 at 05:14, Demetrios Matsakis via time-nuts <
> > > time-nuts at lists.febo.com> wrote:
> > >
> > >> A few years ago I talked with Prof. Liu at Univ of Tennessee.  She and
> > her
> > >> students had measurements all over the USA. Here is an interesting
> > recent
> > >> paper of hers: https://par.nsf.gov/servlets/purl/10234030, which has
> > >> references to still other papers.  Her bio at the end tells a little
> > more
> > >> about her activities.
> > >>
> > >>> On Feb 27, 2023, at 2:23 PM, folkert via time-nuts <
> > >> time-nuts at lists.febo.com> wrote:
> > >>> Hi,
> > >>>
> > >>> Has anyone experimented with measuring the net frequency? (50Hz in
> > >>> Europe, 60Hz in the USA)
> > >>>
> > >>> Me and a friend are trying to do this as accurate and precise as
> > >>> possible. His solution can do that with only a 0.0006Hz error, mine
> > >>> sofar does +/- 2Hz.
> > >>> Deviations of max. 0.150Hz are allowed (according to
> > >>> https://www.mainsfrequency.com/ ) so 2Hz is useless.
> > >>>
> > >>> I tried the following:
> > >>>
> > >>> - use the hardware comparator of an AVR328 (Arduino Nano) together
> with
> > >>>   a 10kHz clock-source and then count the number of external
> > clock-ticks
> > >>>   between 2 falling edges.
> > >>>
> > >>> - I used something like
> > >>>
> > >>
> >
> https://www.botnroll.com/en/outros/4301-230vac-voltage-sensor-for-arduino.html
> > >>>   to make the 230V into a 5V (DC) sine wave and connected that to D6
> of
> > >>>   the Arduino. D7 is connected to a voltage divider to get a 2.5V
> > >>>   voltage reference (should be the zero-crossing voltage of the 230V
> > >>>   input).
> > >>>
> > >>> - connected a PicDiv from Tom (a PD03) to an OXCO and the other end
> to
> > >>>   pin D2 (ext interrupt) of the Arduino.
> > >>>
> > >>> +/- 2Hz (that's 80PPk right?) is way too much. So i'm curious if
> > someone
> > >>> has a suggestion on how to improve this?
> > >>>
> > >>>
> > >>>
> > >>> Regards,
> > >>>
> > >>>
> > >>> Folkert van Heusden.
> > >>>
> > >>> p.s. the source code is at https://vanheusden.com/permshare/50hz.ino
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-- 
Jeremy Nichols
Sent from my iPad 6.