[time-nuts] Re: measuring the mains frequency

[Sanjeev Gupta]

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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