[time-nuts] Re: Power line timing -- setting a clock

[Andy Talbot]

Here in the UK we have a grid that is not synchronised to Europe which for
many years has kept to within +/- 20 seconds or so of UTC according to
my casual monitoring.  However, in the last decade, I've noticed the timing
excursions getting larger, perhaps to as much as -50s before it corrects
over the next few days. I almost certainly do not have the zero reference
correct, but I've definitely seen as much as one minute deviation overall
in a space of a few days to a week.

I have a continuous real time display of frequency and time discrepancy,
but it doesn't have logging - something I always intend to do but never get
a round tuit.   It's bit of an empirical observation, but I've noticed the
wider swings in timing are when the weather is windy, and even more so,
windy and sunny in summer when power generation (as reported by
https://www.gridwatch.templar.co.uk/ )  has more than 50% coming from wind
and solar.

This makes sense as those two sources have no ability to control frequency
- they just generate at whatever frequency the Grid happens to be at. In
cold, windless dark conditions gas and nuclear provide the bulk of energy
and those are the ones National Grid have complete control over, so can
maintain timing more closely.

I can't help wondering if solar and wind inverters could be designed to
push energy into the grid with leading or lagging power factor.  The
ability to set PF from Nat-Grid central control would give them the same
advantage as being able to speed up or slow down the gas / nuclear
generation.  There is a huge base of wind generation already on place, and
this is being extended so it may be too late to ask for retrofitting, but
the inability to control frequency can lead to catastrophic instability and
cascade of minor faults - as witnessed in August 2019 when 10% of the UK
supplies automatically shut down to maintain a rapidly dropping frequency
caused by two simultaneous failures.   It was short lived before N-Grid
could correct things within tens of minutes, but still a "major failure".
https://assets.publishing.service.gov.uk/media/5d96100340f0b61743bd4cc3/20191003_E3C_Interim_Report_into_GB_Power_Disruption.pdf

There are manuy other reports on it worth a read.
It was August with  solar and wind generation up.  It was certainly windy
over that period as I was at a festival where tents were wildly flapping
and getting blown away. I suspect over 60% of the generation at the time
was wind.  The festival was all powered by local generators, so I would
never have noticed any grid power outage other than total internet failure
for a while that afternoon.

Andy
www.g4jnt.com



On Tue, 26 Mar 2024 at 08:13, Larry McDavid via time-nuts <
time-nuts at lists.febo.com> wrote:

> Thank you, Walt, for reporting the time-inaccuracy of mains-synched
> clocks that I see. I'm glad you are far distant from me, and so you have
> data from a new location and generation utility.
>
> I last set all my appliance and mains-synched clocks late on March 9, to
> advance the time for DST. I just checked and all the mains-synched
> clocks roll the minute digit simultaneously and all are now about 24
> seconds fast of GPS time after about two weeks. Historically here, the
> mains clocks being fast is unusual; it is more common for them to run
> slow. But, a 24 second error is not unusual.
>
> I'm in Southern California and Walt is in Washington, also on the west
> coast but not near me. So, this mains frequency effect on old clocks is
> not local to my independent-utility city.
>
> Please folks, stop quoting specs that may or may not still be valid and
> may or may not be complied with by electric generation utilities.
> Instead, let's get data!
>
> I have long set all my appliance clocks to the second, even though they
> don't display seconds. The final button-push in the time-setting command
> will start the clock time at the zero second. Try it! Use a
> known-accurate (e.g. GPS) clock and set your appliance clocks, then
> check them again in a few days or more against your accurate clock.
> Report the results and your location. That's data!
>
> I bought one of the new-Heathkit LED clock kits a few years ago; this
> new design is a mains-synched clock. I have never built that kit but I
> was disappointed to hear user complaints that it did not keep accurate
> time. In fact, though, those that were assembled may just have been
> showing the same mains-frequency issue we are discussing.
>
> There are some cell phone apps that will read the phone's GPS and show
> time to the second. I use "Sol Et Umbra" (it's a sundial application)
> and "Atomic Time," which shows a sweeping second hand; both are free and
> Android apps.
>
> I recommend the Geppetto GPS Clock offered on Tindie; its red LED
> display (including tenth seconds) closely resembles that of the old
> Heathkit GC-1000 clock; the latest versions access multi-GNSS signals.
>
> Best wishes,
>
> Larry McDavid W6FUB
> Anaheim, California (SE of Los Angeles, near Disneyland)
>
>
> On 3/25/2024 1:59 PM, Walt wrote:
> > You are not alone.  I was intrigued by this thread, so I plugged in my
> Heathkit GC-1005 mains-powered digital clock and set the time against my
> PST-1030 WWV Time Clock.
> >
> > I went outside to do some chores, and when I came back in 3 1/2 hours
> later, I'll be darned if the clock was not 3.5 seconds ahead already!  Now
> it's been almost 4 hours and the Heath is almost 4 seconds ahead.
>
> ...
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