[time-nuts] Line Frequeny Stablity
kb8tq at n1k.org
Wed Apr 5 21:35:39 EDT 2017
Well ok, the rest of the story ….
The process of watching the line voltage slip lead me to buy my first “frequency counter”.
It was a 1950’s vintage tube based Beckman “EPUT Meter”. I doubt it cost me over $40 at
the time. It was well used but still functional It clocked away on a massive MHz time base
(that’s singular not plural) and turned out to be plenty good enough to show jitter
on a 60 Hz sine wave. That got me into questions about why and stability and …. here I am
> On Apr 5, 2017, at 7:57 PM, Jeremy Nichols <jn6wfo at gmail.com> wrote:
> A fun way to monitor the state of the grid is to watch the web site of
> the Power
> Information Technology Laboratory <http://powerit.utk.edu> at the University
> of Tennessee <http://www.utk.edu>, Their site lists in both tabular and
> graphical (map) form the frequency of the grid. Most of it is USA-based but
> there are a few other countries also monitored.
> I have one of the monitors (in the table display page <
> http://fnetpublic.utk.edu/tabledisplay.html> my monitor is #853 in the
> Western Interconnection—I'm in California).
> The monitors, about the size of a thick hardback book, plug into a
> convenient AC line outlet, connect to your Internet router, and have a
> small puck-style GPS antenna so that it knows the time and where it is. The
> unit has an LCD display of date, time, line voltage, and line frequency.
> The voltage is shown to 3 decimal digits of resolution and the frequency to
> four digits.
> I got my monitor from the U of T after I sent them a report on my home-made
> monitor's results. It's interesting to watch the frequency wander up and
> down but always average very close to 60.000 Hz. They saw I had an interest
> and offered me one of their toys. The only thing it doesn't do is connect
> to my PC so I can monitor it long-term. I suppose if I were clever with
> network stuff there'd be a way to tap into its data stream.
> Jeremy, N6WFO
> On Wed, Apr 5, 2017 at 2:12 PM, Bob kb8tq <kb8tq at n1k.org> wrote:
>> Back in high school, one of the radio club members figured out that the
>> “clock adjustment” took place
>> locally between 4:30 and 5:00 PM. Needless to say, pretty much everybody
>> spent the next week listening
>> to WWV and watching the clock’s second hand go out of sync with the beeps.
>> This was back in the late 1960’s
>> and the idea of a grid was a bit looser than it is today. Indeed it was
>> post 1964 so there *were* grids big
>> enough to take out the whole north east section of the US. Since we were
>> very much in that area the
>> topic of grid sync came up. Nobody ever really had a good answer to that
>> question. That included the
>> guys who ran the local power company.
>>> On Apr 5, 2017, at 3:05 PM, Hal Murray <hmurray at megapathdsl.net> wrote:
>>> preilley_454 at comcast.net said:
>>>> When I installed power plants in the 1970's they has a special "clock"
>>>> showed the cumulative error in terms of clock time.
>>> How big were the grids back then?
>>> What was the typical range of error over a day or month?
>>>> If the generator ran a little too fast the clock would move forward.
>>>> the operator observed the clock moving away from zero he would reduce
>>>> plant's power and the clock would move backward toward zero. ...
>>> Does that operator control a single generator or a whole grid?
>>> Does having a human in the loop help the control loop stability?
>>> These are my opinions. I hate spam.
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