At 10:00 AM 8/22/2005, you wrote:

Try Siemens or ABB then, Ferranti has been taken over if I recall.

You do? Are you sure?

That is certainly the case of older meters and in many states. But is most
definitely not true of newer meters in many jurisdictions. Many regulators
in the US have been very slow on a world basis, to accept newer metering
technology, the New York DPS only registering a wide range of fully solid
state units in 2003.

Quite true, hence the reason that many electricity sellers are pushing for
the introduction of solid-state meters much quicker than many regulators
are able to handle.

And herein lies a serious problem for electricity suppliers. With the
problems of inadequate generating capacity and ever increasing demand,
particularly in North America, regulators are directing distributors on
occasions to drop nominal voltages to 100V in controlled brown-outs.
Induction meters then, apparently, tend to read even lower, thus depriving
the distributors of yet more income.

In that case the US will be playing catch up with parts of Canada, Europe,
most of Asia and Oceania where solid state meters, often with remote
reading are the norm rather than the exception - and synchronised mains
frequency has become a fond memory.

John Day

Hi Alberto,

The US is replacing meters too, but they are still "Ferraris" electromechanical
meters with electronic readouts.  The power grid will still need to be kept
to a reasonable accuracy for the meters to read with a reasonable accuracy.

The Ferraris type meter (G. Ferraris died 3 years before anyone patented
an electric power meter...)  has been refined to a point where its ultimate
accuracy is 0.01%, but that requires the frequency to be held to a similar
degree of precision.

We have probably allowed this discussion to stray a little far from
"precise time...measurement"  I think I'll rein in my end of things...

-Chuck Harris

Alberto di Bene wrote:

John Day wrote:

The term is actually Ferraris, after Galileo Ferraris, the inventer of
the AC induction motor.  As far as I can tell, he had nothing to do with
watt-hour meters, as they weren't invented until 3 years after his death.

Pretty sure. we have at least 1 per household,  and a whole pile for
commercial establishments, and they are salted all over the place on
traffic lights, billboards, street signs, ...  Surely no place else in the
world could be as stupid about such things as we are!

During a brownout, the power company is providing substandard power,
and should be paid accordingly!  100V brownouts blow induction motors
right and left.  An induction motor will draw whatever current is necessary
to meet its load requirements, regardless (to a point) of its supply
voltage.

There are plenty of remote reading meters in the US, but they all seem to be
of the Ferraris type in their measurement transducers.

-Chuck Harris

Poul-Henning Kamp wrote, quoting me,

">Power companies bill on time-integrated power - watt-hour

Uhm, sorry, that is just plain wrong.  The Ferrantis (sp?) power
meter which is the most widely used meter in the world is not
frequency sensitive within a band of +/- 10% or more."

You are correct, and I sit corrected. I was looking for a
simple example of why frequency mattered. I did not feel good
abut it as I wrote, but I didn't look it up. I knew that
crossed-coil wattmeters were not sensitive to frequency as
long as the coil inductance didn't matter.

">1. It is unlikely that any power network just lets itself go,

Does not follow."

Well, it doesn't follow from the watt-hour meter, but look at
the larger network picture. The most certain way to tell that
the network supplies and loads are not balanced is to measure
the frequency. The frequency reflects the speed of the generators.
Generator speed is determined by the balance between steam power
to the turbine and load on the generator. Steam power determines
fuel cost.

If the frequency is used to determine power balance then it
follows that all users of the network must agree on a nominal
frequency. Given a nominal frequency and the ability to detect
overload by dropping frequency then it is possible to protect
the network before the generators come to a stop. This is not
linear because the load goes up as frequency drops and transformer
iron saturates.

As an example of the relationship between steam power and frequency,
there was a paper mill with three generators driven by co-generation
turbines. That is, the local boilerhouse steam pressure had to be
let down anyway, so turbines were used to drop 400 PSI steam to 30
PSI steam for low pressure equipment. It happened that an oil leak
froze the governor for one of the turbines. The operator wanted to
shut the turbine down, but forgot his training. Instead of closing
the manual steam valve, he tripped the generator's circuit breaker.
This left the generator and turbine with no load and full steam.
The turbine and generator rapidly accelerated beyond their rated
speeds. The generator disintegrated and threw cubic foot chunks of
metal through the roof. No one was killed, somehow, but the operator
was badly burned by escaping steam.

Bottom line, it is within reason that some networks do not synchronize
clocks with something standard. It is not reasonable that the network
dispatchers do not care about frequency and do not work to regulate it.
It's not regulated with any accuracy that we'd spend much time discussing
on this list but it is regulated.

When I toured the Pennsylvania, New Jersey and Delaware dispatch center
some years ago, I thought they had talked about keeping a daily cycle
count. The count had economic importance, in that a high count meant
that sources gave power away and a low count meant that users paid too
much. I can't justify that in terms of the fact that power is VxI on
the real axis. It has no frequency component. (Plain old VxI measured
with separate meters is volt-amps and VxI on the imaginary axis is
volt-amps reactive or VARS.)

Too bad that there's no one that understands power dispatching that
also has an interest in precision time.

How many of you have collected a radio clock that was meant to compare
time on a local power network with WWV or something more recent? Are
they still being made?

Regards,
Bill Hawkins

In message 003c01c5a74d$b95c9520$0500a8c0@darius.domain.actdsltmp, "Bill Hawkins" writes
:

I didn't say it was not true, I only said it didn't follow from
your argument about the power-meter :-)

The specs for the Nordpool area sets some specific frequency bands,
voltage bands and time constants for which regulation regime applies.

The result is that the frequency is generally a tad on the low side,
but well inside the tolerance, because nobody sees it as their job
(and expense) to keep the average at 50Hz.

--
Poul-Henning Kamp      | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG        | TCP/IP since RFC 956
FreeBSD committer      | BSD since 4.3-tahoe
Never attribute to malice what can adequately be explained by incompetence.

"In July, film director David Lynch announced that he had
formed a foundation to raise $7 billion to fund 8000
Transcendental Meditation practitioners to bring world
peace by creating a "unified field" of stress-free brain
waves over the Earth, which TMers accomplish, as they
describe it, by detaching their minds from the 'thinking
process.'"

He goes on to say that the cost of training has gone up
since John Hagelin needed only $4.2 million in 1993 to
take 4000 TMers to Washington, D.C., to reduce crime for
eight weeks.

Is there any tie-in? We don't know. You are free to speculate.

Personally, I think the only way to world peace is to eliminate
the human predators, leaving only the sheep. Good leadership
might be hard to find, though.

Regards,
Bill Hawkins