Why do street lights flicker in snowy weather?
Eddie
A radio phone-in got a lot of people talking about flickering street
lights.
Is there a real connection between bad weather and flickering street
lights. If so then how does it work?
Sam Wormley
Can you be precise? Frequency of flickering? Snow required? humidity?
Cold? Exceptions?
Adrian C
>> Is there a real connection between bad weather and flickering street
>> lights. If so then how does it work?
>>
>
> Can you be precise? Frequency of flickering? Snow required? humidity?
> Cold? Exceptions?
>
Tea.
--
Adrian C
Androcles
"Eddie" <du...@invalid.com> wrote in message
news:Xns9CE63B9...@feeder.eternal-september.org...
were power cuts also. Do you live near any rail system? The shoe
on the third rail makes some pretty impressive lightning which lights
up the clouds - especially in a fog or snow storm.
Archimedes' Lever
wrote:
Light reflecting off the snow causes the opto-sense switch to trip?
I have seen light flicker in good weather, so your claim of cause and
effect are likely flawed.
IOW, it isn't the weather or the temperature. It is observer error.
Eddie
The flicker I saw a few days ago was about 2 or 3 times a second.
The radio callers weren't specific about their local conditions but
just said "my street light is flickering here too".
In my case in South East England a cold snap was just starting and
there was about 2 inches of snow and temperatures were a few degrees
below freezing. The winds were unusally high for the area (perhaps
VERY roughly 30 mph).
It could just be coincidence but the radio callers got me thinking
that maybe there's an electrical explanation. Any observations or
ideas?
johnwright
I wouldn't have thought there was anything electrical about it, unless
it was variation in the supply. Most street lights are low pressure
sodium lights and run internally at about 100C in order to vapourise the
sodium - all internally generated by the initial argon/neon discharge -
one reason they take several minutes to warm up as do most light
sources other than incandescent or LED light sources being notable
exceptions.
This in itself makes them insensitive to ambient conditions.
There would be a variation in warm up time depending on the ambient
temperature - the colder it is the longer it takes. (You can see this
with CFL lights especially ones used outside. The ones I have in my yard
take several minutes to produce full output especially when its really
cold outside). Even the HP sodium lights you often see take time to warm
up as well. They are like LP sodium lights except the two well known
sodium lines are pressure broadened to give better colour rendering.
--
I'm not apathetic... I just don't give a sh** anymore
?John Wright
Steve Firth
> It could just be coincidence but the radio callers got me thinking
> that maybe there's an electrical explanation. Any observations or
> ideas?
Yes, it's quite simple. Callers to local radio stations are drawn from
the lower 5% of human ability. Anything they say can be safely ignored
because it's bound to be vacuous crap. HTH.
What local radio needs is another James Stannage to tell the dimwits
phoning in that they are indeed dimwits who are a waste of oxygen that
could be used more productively on keeping slugs alive.
Mike Barnes
>What local radio needs is another James Stannage to tell the dimwits
>phoning in that they are indeed dimwits who are a waste of oxygen that
>could be used more productively on keeping slugs alive.
Sadly, I don't think there will never be another James Stannage. Thanks
for reminding me of him. You and he have a lot in common. :-)
--
Mike Barnes
Steve Firth
>
> Sadly, I don't think there will never be another James Stannage. Thanks
> for reminding me of him. You and he have a lot in common. :-)
Such kind words, and I do actually mean that. I had a deal of respect
for the bloke ever since I accidentaly tunesd into Piccadilly Radio when
I was a student. Listening to him baiting the drunks who phoned in late
on Friday night was a pleasure.
Tzortzakakis Dimitrios
� "Eddie" <du...@invalid.com> ������ ��� ������
news:Xns9CE63B9...@feeder.eternal-september.org...
blown bulbs with fresh ones?
--
Tzortzakakis Dimitrios
major in electrical engineering
mechanized infantry reservist
hordad AT otenet DOT gr
Mike P
Heh. I remember him. Alan Beswick was another local radio hero...
Mike P
jmfbahciv
<snip> that wasn't helpful at all.
/BAH
jmfbahciv
during lightning storms. Most of that occurred when demand was almost
equal to capacity.
Can you describe the flickering? Were the lights really flickering
or was the snow so bad that snow blown sideways blotted out the light
momentarily?
/BAH
Sam Wormley
So it could be a street light on its "last legs" and the "feedback"
internal to the gasses and current may have some temperature
sensitivity. If that is the case, the "flickering" will only get
worse.
Andrew Gabriel
Eddie <du...@invalid.com> writes:
> On 00:27 19 Dec 2009, Sam Wormley wrote:
>
>> On 12/18/09 6:21 PM, Eddie wrote:
>>> In the UK we currently have cold winds and snow.
>>>
>>> A radio phone-in got a lot of people talking about flickering
>>> street lights.
>>>
>>> Is there a real connection between bad weather and flickering
>>> street lights. If so then how does it work?
>>>
>>
>> Can you be precise? Frequency of flickering? Snow required?
>> humidity? Cold? Exceptions?
>
> The flicker I saw a few days ago was about 2 or 3 times a second.
I've seen this with SOX (low pressure sodium) lamps as one of
the end-of-life failure modes, although it's not the most common
SOX failure mode. With the 35W SOX used on smaller roads, it could
be the starter repeatedly restarting a lamp which isn't sustaining
an arc anymore.
> The radio callers weren't specific about their local conditions but
> just said "my street light is flickering here too".
Description too devoid of information to even guess on the
cause. They could each be describing something completely
different.
> In my case in South East England a cold snap was just starting and
> there was about 2 inches of snow and temperatures were a few degrees
> below freezing. The winds were unusally high for the area (perhaps
> VERY roughly 30 mph).
If the streetlamps have their own didicated overhead
supply (now very rare in the UK), then maybe that's
arcing somewhere in the wind.
> It could just be coincidence but the radio callers got me thinking
> that maybe there's an electrical explanation. Any observations or
> ideas?
--
Andrew Gabriel
[email address is not usable -- followup in the newsgroup]
Huang
>
> - Show quoted text -
Probably a disturbance in the power distribution grid. Somewhere on
the grid a transformer probably blew out, or a power line failed.
I saw a transformer fail last week and it was very, very bright. Lots
of arcing and it lasted quite a while. I think that it was arcing for
about 5 or 10 minutes, looked like a welding light. That can cause
fluctuations in the power distribution grid which will cause lights to
flicker - for sure.
The same thing happens when they electrocute an innocent person in
Texas - all of the lights flicker and the face of Jesus emerges from
the white noise on their TV sets.
Sam Wormley
>
> Probably a disturbance in the power distribution grid. Somewhere on
> the grid a transformer probably blew out, or a power line failed.
>
> I saw a transformer fail last week and it was very, very bright. Lots
> of arcing and it lasted quite a while. I think that it was arcing for
> about 5 or 10 minutes, looked like a welding light. That can cause
> fluctuations in the power distribution grid which will cause lights to
> flicker - for sure.
>
> The same thing happens when they electrocute an innocent person in
> Texas - all of the lights flicker and the face of Jesus emerges from
> the white noise on their TV sets.
>
I had no idea!
James Sweet
Cold temperature raises the strike voltage of discharge lamps. HID lamps
have small arc tubes which warm up quickly and are less prone to this,
but low pressure sodium lamps common in Europe (the saturated orange
ones that are pink when they first come on) have long discharge tubes
with a lot of surface area and are electrically more similar to
fluorescent lamps may have more trouble in cold weather. If the strike
voltage is higher than the peak voltage the ballast can deliver, the arc
will extinguish. If the voltage is just barely sufficient, the lamp can
flicker.
BrianW
He was awesome. I remember listening to his late night show on Red
Rose Radio in the mid 90s. He had a particular ability at handling
pissed up scousers who called in to heckle him.
Mike P
TKM
"James Sweet" <james...@gmail.com> wrote in message
news:hgj75t$jbj$1...@news.eternal-september.org...
This explanation confirms what I see with such lamps in cold weather. The
older the lamp, the higher the strike voltage and so the more likely it is
to flicker. Eventually, the energy from the flickering arc should warm the
lamp enough to sustain it without flickering (unless the lamp is at
end-of-life) so it would be interesting to hear from anyone who has watched
a flickering lamp for a while to see if that indeed does happen.
Someone mentioned that the cause of the flicker might be due to the
luminaire's photocell getting mixed signals due to reflection from the snow.
Photocells usually have a delay circuit built in; otherwise, they would
react to lightning flashes or headlight beams sweeping by.
TKM
Andrew Gabriel
"TKM" <nom...@no.net> writes:
>
> "James Sweet" <james...@gmail.com> wrote in message
> news:hgj75t$jbj$1...@news.eternal-september.org...
>> Eddie wrote:
>>> In the UK we currently have cold winds and snow. A radio phone-in got a
>>> lot of people talking about flickering street lights.
>>>
>>> Is there a real connection between bad weather and flickering street
>>> lights. If so then how does it work?
>>>
>>
>>
>> Cold temperature raises the strike voltage of discharge lamps. HID lamps
>> have small arc tubes which warm up quickly and are less prone to this, but
>> low pressure sodium lamps common in Europe (the saturated orange ones that
>> are pink when they first come on) have long discharge tubes with a lot of
>> surface area and are electrically more similar to fluorescent lamps may
>> have more trouble in cold weather. If the strike voltage is higher than
>> the peak voltage the ballast can deliver, the arc will extinguish. If the
>> voltage is just barely sufficient, the lamp can flicker.
>
> This explanation confirms what I see with such lamps in cold weather. The
> older the lamp, the higher the strike voltage and so the more likely it is
> to flicker. Eventually, the energy from the flickering arc should warm the
> lamp enough to sustain it without flickering (unless the lamp is at
> end-of-life) so it would be interesting to hear from anyone who has watched
> a flickering lamp for a while to see if that indeed does happen.
With the SOX I've seen doing this, the flicker is happening when fully
run-up. I haven't watched one of these during run-up, so I don't know
if it happens during run-up. Temperature wasn't low when this happened,
and I suspect that's not relevant.
I don't have a sample dead one with this failure mode (which isn't
common), so I can't inspect the lamp to see what visible failure
indication there might be. As a pure guess, I might speculate that
the emission material is sputted off the electrodes, and it can't
sustain an arc in thermionic emission mode. The 35W SOX has an
ignitor/starter which is probably repeatedly trying to start it.
The larger ones use a leakage reactance transformer to provide both
the starting voltage and current limiting, because the arc voltage
is too high for a simple series ballast on 240V, and so don't need
an ignitor/starter. I don't think I've seen the larger ones flashing;
when the emission coating wears out, they seem to fail to light up
at all (or with only a very dim glow around the electrodes which
you can't see from the ground).
IME more common failure mode of SOX is the arc tube develops a leak
and the sodium is ejected into the outer vacuum tube, where it often
forms an opaque mirror coating on the inside of the bulb facing
the ejection point, so the light no longer escapes through part of
the bulb (can block out most of it eventually). The arc tube seems
to be able to lose a lot of sodium in this way, yet still work, but
eventually it turns into a dim red neon light which never runs-up
(nicknamed a "red burner"), as there's no longer enough sodium left
in the arc tube, just the neon starting gas.
johnwright
> � "Eddie" <du...@invalid.com> ������ ��� ������
> news:Xns9CE63B9...@feeder.eternal-september.org...
>> In the UK we currently have cold winds and snow.
>>
>> A radio phone-in got a lot of people talking about flickering street
>> lights.
>>
>> Is there a real connection between bad weather and flickering street
>> lights. If so then how does it work?
>>
> Because of utility privatisation they don't service the lights, exchanging
> blown bulbs with fresh ones?
I don't think they ever did. They did a planned maintenance thing which
was replacing all the bulbs whether working or not. I saw a private
contractor doing that the other day.
James Sweet
>
> Someone mentioned that the cause of the flicker might be due to the
> luminaire's photocell getting mixed signals due to reflection from the snow.
> Photocells usually have a delay circuit built in; otherwise, they would
> react to lightning flashes or headlight beams sweeping by.
>
> TKM
>
>
Many photocells, particularly older ones, are thermal. The CdS cell
controls current flowing through a piece of resistance wire wound around
a bimetal strip. When sufficient light falls on the cell, the strip is
heated, it bends and opens the contacts. This inherently creates a
delay. Electronic photocells are designed with hysteresis for the same
reason, normally the delay is around a minute.
James Sweet
>
> With the SOX I've seen doing this, the flicker is happening when fully
> run-up. I haven't watched one of these during run-up, so I don't know
> if it happens during run-up. Temperature wasn't low when this happened,
> and I suspect that's not relevant.
>
>
Another characteristic of SOX is that the lamp voltage (and power
consumption) rise rather significantly over the life of the lamp. This
causes the same issue, eventually the voltage is higher than the ballast
can supply and the arc will become unstable and flicker. These things
usually fail due to either sodium depletion or the electrode seals fail
from the corrosive action of the heated sodium, but an older lamp
coupled with colder weather, especially if the ballast is a choke rather
than a leak autotransformer, they can do this instead. HPS lamps will
not restrike hot, so when they reach end of life they normally will
cycle, but SOX will usually restrike even hot, so they can flicker.
MadManMoon
wrote:
What most often happens is that the lamp shuts off completely, and then
restarts, which takes it just as long to pump up as before because the
run temp is far higher than the shut off idle temp, even if after only a
couple minutes.
I used to make a joke and said that I shut them off 'with my aura' all
the time because we often saw them shutting off as we approached while
out getting a buzz, back in 'the day'.
Proteus IIV
wrote:
> On Fri, 18 Dec 2009 18:27:31 -0600, Sam Wormley <sworml...@gmail.com>
YOU ARE AN IDIOT
GO FLICKER YOUR SHAPESHIFTING ANUS TO YOUR USUAL GAYTARD NEWSGROUP
I AM PROTEUS
BrianW
Marvellous. Typo in my post - it was mid 80s, not 90s. Admittedly,
outwitting pissed up retards isn't hard, but it's fun. I guess that
usenet could be said to be a spiritual successor to Mr Beswick's show.
Are you from the Lancs area originally, btw?
Jeremy Parker
"Sam Wormley" <swor...@gmail.com> wrote
[snip]
>> The same thing happens when they electrocute an innocent person in
>> Texas - all of the lights flicker and the face of Jesus emerges
>> from
>> the white noise on their TV sets.
>>
>
>
> I had no idea!
Well, if they are all guilty, you wouldn't see it very often
Jeremy Parker
Tzortzakakis Dimitrios
? "jmfbahciv" <jmfbahciv@aol> ?????? ??? ??????
news:hgioc...@news3.newsguy.com...
> Eddie wrote:
>> In the UK we currently have cold winds and snow. A radio phone-in got a
>> lot of people talking about flickering street lights.
>>
>> Is there a real connection between bad weather and flickering street
>> lights. If so then how does it work?
>>
> When I lived in Massachusetts, the only times my lights flickered was
> during lightning storms. Most of that occurred when demand was almost
> equal to capacity.
>
a waste, if less there would be serious stability issues. That's the problem
with wind turbines, you just don't know when the wind blows, and you have to
cover each MW of wt with at least of 700 kW conventional reserve, because
when the wind stalls what? Stop everything?
> Can you describe the flickering? Were the lights really flickering
> or was the snow so bad that snow blown sideways blotted out the light
> momentarily?
>
--
James Sweet
Yeah that's what I was saying with HPS (metal halide and mercury behave
similarly). The higher pressure in a hot arc tube raises the strike
voltage beyond what is available from the ballast. It has to cool until
the pressure reduces to a point that the arc will strike.
SOX lamps are much lower pressure to begin with and will usually
restrike hot.
dh...@shawcross.ca
"Tzortzakakis Dimitrios" <no...@nospam.com> wrote in message
news:hglue7$dol$1...@mouse.otenet.gr...
>
> Demand is always almost equal to capacity. If it would be more, it would
> be a waste, if less there would be serious stability issues.
-----------------------------
Please check the definitions of demand and capacity - as the above is
nonsense.
Ideally the capacity should exceed the demand by some optimal margin but as
adding and dropping on line capacity is in blocks corresponding to the
capacity or rating of individual generators, and demand is up to the
customers (predictable but not controllable) the capacity will normally
exceed the demand by a fairly large margin at times- there is no "stability"
problem. As for waste by having extra on-line generation- economic dispatch
optimization is a common procedure.
If demand exceeds capacity, then problems can occur- not necessarily
stability problems.
As for the wind turbine reserve, you are being a bit over optimistic. You
are assuming 30% availability of wind capacity. In practice, from recent
data it appears that 10-15% is a better figure and this is a statistic based
on an annual average, which means nothing if wind fails. In other words.
reserve capacity must be available for the worst case situation- 100%
failure of any generation source, concentrated as in a 500MVA fossil plant
or distributed as in 500-1MVA wind units in a region where wind diversity is
small.
--
-----
Don Kelly
cross out to reply
Mike P
Yes, I'm from the Rossendale Valley. My brother and some family still
live up there. I grew up in Waterfoot, but my dad worked in Hong Kong at
the time, so we split our time between a small lancashire village and
Hong Kong. Talk about different ends of the scale...! My mates and I
always used to listen to Alan Beswick on Red Rose and talk about it at
school the day after.
Mike P
Andrew Gabriel
<dh...@shawcross.ca> writes:
>
>
> "Tzortzakakis Dimitrios" <no...@nospam.com> wrote in message
> news:hglue7$dol$1...@mouse.otenet.gr...
>>
>> Demand is always almost equal to capacity. If it would be more, it would
>> be a waste, if less there would be serious stability issues.
> -----------------------------
> Please check the definitions of demand and capacity - as the above is
> nonsense.
>
> Ideally the capacity should exceed the demand by some optimal margin but as
> adding and dropping on line capacity is in blocks corresponding to the
> capacity or rating of individual generators, and demand is up to the
Most of the generators have variable power output, not simply on
or off.
> customers (predictable but not controllable) the capacity will normally
> exceed the demand by a fairly large margin at times- there is no "stability"
> problem. As for waste by having extra on-line generation- economic dispatch
> optimization is a common procedure.
> If demand exceeds capacity, then problems can occur- not necessarily
> stability problems.
Frequency drops below nominal, and conversely when supply exceeds
demand, frequency increases above normal. There's a requirement in
the UK for frequency to average out correctly long-term (so things
like synchronous clocks don't drift long-term), consequently,
supply has to exactly match demand long-term. However, since the
demand and supply can't exactly track each other short term due to
inherent lags, there are periods of both demand exceeding supply,
and supply exceeding demand. These are both inevitable due to the
supply lag with different types of plant and unexpected plant
failures on some occasions, and deliberately forced to correct for
earlier drifts on other occasions.
There is contingency reserve in addition to the supply - additional
plant spinning sychronous online ready when needed due to either an
increase in demand or an unexpected loss of supply, and yet more
plant offline ready to run up and cut in with a bit more notice.
A longer article I wrote on this some years back, with some examples
of how it was applied in the UK to some specific historic events,
and how it went wrong on one occasion...
http://groups.google.co.uk/group/sci.engr.lighting/msg/99b03c9711a4f753?hl=en
> As for the wind turbine reserve, you are being a bit over optimistic. You
> are assuming 30% availability of wind capacity. In practice, from recent
> data it appears that 10-15% is a better figure and this is a statistic based
> on an annual average, which means nothing if wind fails. In other words.
> reserve capacity must be available for the worst case situation- 100%
> failure of any generation source, concentrated as in a 500MVA fossil plant
> or distributed as in 500-1MVA wind units in a region where wind diversity is
> small.
The BBC did a programme about the wind power in Denmark, one of
the highest users of wind power. In spite of installing lots of
turbines and being able to point to all the power they get from them,
they haven't been able to spin down any conventional generating
station, because they need them when the wind stops. When the wind
blows, they have an excess of conventional electricity which they
sell, but for their neighbours, it's effectively as unreliable as
the wind, since its export stops as soon as the wind stops, so it
only commands a low price as an unreliable source. This combined
with a failure of a transmission circuit, plunged much of central
Europe into darkness a couple of years ago when supply suddenly
fell well short of demand, and emergency load shedding was initiated.
BrianW
Indeed!
I lived near Chorley, went to school in Leyland. Our headmaster lived
up in Rossendale, IIRC.
> My mates and I
> always used to listen to Alan Beswick on Red Rose and talk about it at
> school the day after.
Same here. I had forgotten all about Alan Beswick until this thread.
I remember one of my favourite calls. Some hapless guy phoned in
saying he fancied becoming a radio DJ and asking how to apply. Alan
helpfully explained that he should make a demo tape and send it to Red
Rose, and gave him the relevant address. The guy then asked "What do
I put on the demo tape?". Alan said "So you want to be a DJ and you
don't know what to put on your demo tape?". "Yes". "Well you
haven't got a bloody chance then". <click>
I also remember the ongoing battles with scousers. At least once,
following a stream of abusive Liverpudlians, he declared "no more
scousers tonight" and simply cut them off after the first "allright
Alan".
johnwright
> On 20 Dec, 23:36, Mike P <n...@here.com> wrote:
>> On Sun, 20 Dec 2009 02:54:24 -0800, BrianW wrote:
>>> Are you from the Lancs area originally, btw?
>> Yes, I'm from the Rossendale Valley. My brother and some family still
>> live up there. I grew up in Waterfoot, but my dad worked in Hong Kong at
>> the time, so we split our time between a small lancashire village and
>> Hong Kong. Talk about different ends of the scale...!
>
> Indeed!
>
> I lived near Chorley, went to school in Leyland. Our headmaster lived
> up in Rossendale, IIRC.
I originally came from Southport and went to the Grammar School there.
God knows where the headmaster lived, I think he kept it a secret to
stop kids from going round and shooting him ;-)
He never liked me for some reason and took it out in the end on my
brother who never did anything to offend - with the result I think he
would have had at the very least two assassins! I had teachers who stood
up in my support against the headmaster. One was a guy called "Danny"
Parsons who came from Wigan. Being ancient (me that is) another of our
teachers we nicknamed "George" had a stiff leg from being shot up in his
days flying Lancasters.
jmfbahciv
> ? "jmfbahciv" <jmfbahciv@aol> ?????? ??? ??????
> news:hgioc...@news3.newsguy.com...
>> Eddie wrote:
>>> In the UK we currently have cold winds and snow. A radio phone-in got a
>>> lot of people talking about flickering street lights.
>>>
>>> Is there a real connection between bad weather and flickering street
>>> lights. If so then how does it work?
>>>
>> When I lived in Massachusetts, the only times my lights flickered was
>> during lightning storms. Most of that occurred when demand was almost
>> equal to capacity.
>>
> Demand is always almost equal to capacity. If it would be more, it would be
> a waste, if less there would be serious stability issues. That's the problem
> with wind turbines, you just don't know when the wind blows, and you have to
> cover each MW of wt with at least of 700 kW conventional reserve, because
> when the wind stalls what? Stop everything?
>> Can you describe the flickering? Were the lights really flickering
>> or was the snow so bad that snow blown sideways blotted out the light
>> momentarily?
Shit. I knew I wrote that badly. I'm talking about physical capacity.
/BAH
phil-new...@ipal.net
| In the UK we currently have cold winds and snow.
|
| A radio phone-in got a lot of people talking about flickering street
| lights.
|
| Is there a real connection between bad weather and flickering street
| lights. If so then how does it work?
http://www.youtube.com/watch?v=eYUmdqQ94Ao
--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------
tadchem
> In the UK we currently have cold winds and snow.
>
> A radio phone-in got a lot of people talking about flickering street
> lights.
>
> Is there a real connection between bad weather and flickering street
> lights. If so then how does it work?
What kind of lammps do you have, carbon arc, sodium vapor, mercury
vapor, incandescent, LEDs?
It makes a difference.
Vapor lamps are sensitive to the cold, as they require a narrow range
of pressure internally to function. Cold reduces the presssure,
making operation less reliable.
Cold can also shorten wires. If you have a break internally in an
insulated wire, cold could shrink the metal, weakening the connection
at the break and raising resistance, which heats the wire which
expands again, which drops the resistance, which lets the wire cool
down again, ad nauseum. That is the mechanism for flashers in
Christmas lights and automotive turn signals.
Tom Davidson
Richmond, VA
dh...@shawcross.ca
"Andrew Gabriel" <and...@cucumber.demon.co.uk> wrote in message
news:hgjc21$uh3$1...@news.eternal-september.org...
----------------
I have seen many such lamps flicker but have never associated this with
temperature. I have not seen any more excessive flickering in cold
conditions than in warm conditions
By cold conditions, I mean central Alberta, Canada, -30 to -40C is not all
that uncommon and windchill down to -50C equivalent.
However, there could be differences in design that affect this. As an
example we don't run exterior water or sewer pipes:)
TKM
"tadchem" <tad...@comcast.net> wrote in message
news:a19dcd11-4445-454c...@k4g2000yqb.googlegroups.com...
It makes a difference.
Tom Davidson
Richmond, VA
From a practical standpoint, these days the only lamps that are sensitive to
cold temperatures down to ambient temperatures of about 0 F. (-18 C) are
fluorescent lamps. Even so, special fluorescent lamps are used routinely
at -20F (-29 C) in commercial freezers, outdoor signs and exterior building
lighting. High pressure sodium, high pressure mercury, metal halide, LED,
cold-cathode ("neon") and, of course, incandescent all work just fine. Low
pressure sodium lamps have a "thermos bottle" construction so they may just
take a little longer to warm up. Discharge lamps do require somewhat
higher voltages to initiate the arc at low temperatures, so in applications
where cold temperatures are expected, so-called "minus 20" ballasts are
specified.
The only discharge lamps that I've ever seen flicker in cold temperatures
are CFLs and unprotected or reduced-wattage ("watt miser") fluorescent types
which have been mis-applied. Rarely, a high pressure mercury lamp will
flicker due to a faulty arc tube and there's an odd type of high pressure
sodium lamp designed to work on mercury ballasts that sometimes flickers
near end-of-life. I've heard that high pressure sodium lamps operated on
old series (constant-current) streetlighting systems will flicker; but, if
so, all of the lamps on the circuit will flicker, not just one. I've never
seen that phenomenon, however.
Terry McGowan
Androcles
"TKM" <non...@no.net> wrote in message
news:hgs2pb$k18$1...@news.eternal-september.org...
>
> "tadchem" <tad...@comcast.net> wrote in message
> news:a19dcd11-4445-454c...@k4g2000yqb.googlegroups.com...
> On Dec 18, 7:21 pm, Eddie <du...@invalid.com> wrote:
>> In the UK we currently have cold winds and snow.
>>
>> A radio phone-in got a lot of people talking about flickering street
>> lights.
>>
>> Is there a real connection between bad weather and flickering street
>> lights. If so then how does it work?
>
> What kind of lammps do you have, carbon arc, sodium vapor, mercury
> vapor, incandescent, LEDs?
>
Oh sure, carbon arc street lights... with gilded hand-carved
capitals, chromium plated motors and a Rolls-Royce gearbox.
http://upload.wikimedia.org/wikipedia/commons/6/6c/Staite-Petrie_Lamp_1847.png
http://en.wikipedia.org/wiki/File:Arc_lamp-ignition_%CE%940035.JPG
We use 'em in our refrigerators too, striking an arc when the door opens;
it saves having a little man inside to operate a switch.
Benj
> "tadchem" <tadc...@comcast.net> wrote in message
> What kind of lammps do you have, carbon arc, sodium vapor, mercury
> vapor, incandescent, LEDs?
>
> It makes a difference.
Street lamps are usually sodium vapor some old installations may be
mercury vapor. It's simple economics.
> Vapor lamps are sensitive to the cold, as they require a narrow range
> of pressure internally to function. Cold reduces the presssure,
> making operation less reliable.
Absolutely. Tadchem wins the poster who actually has a brain prize!
When cold high pressure sodium or mercury vapor lamps will flicker or
repeatedly restart if they have lots of hours on them. As someone
noted they are usually just replaced en mass at a certain age so by
that time it's common for many to be at the flicker to not work at all
stage.
> Cold can also shorten wires. If you have a break internally in an
> insulated wire, cold could shrink the metal, weakening the connection
> at the break and raising resistance, which heats the wire which
> expands again, which drops the resistance, which lets the wire cool
> down again, ad nauseum. That is the mechanism for flashers in
> Christmas lights and automotive turn signals.
Possible, but not very likely. More likely is that because of snow
being white and reflective (as opposed to black pavement) people just
tend to NOTICE the flickering more which was really there all the
time.
> Tom Davidson
> Richmond, VA
>
> From a practical standpoint, these days the only lamps that are sensitive to
> cold temperatures down to ambient temperatures of about 0 F. (-18 C) are
> fluorescent lamps. Even so, special fluorescent lamps are used routinely
> at -20F (-29 C) in commercial freezers, outdoor signs and exterior building
> lighting. High pressure sodium, high pressure mercury, metal halide, LED,
> cold-cathode ("neon") and, of course, incandescent all work just fine. Low
> pressure sodium lamps have a "thermos bottle" construction so they may just
> take a little longer to warm up. Discharge lamps do require somewhat
> higher voltages to initiate the arc at low temperatures, so in applications
> where cold temperatures are expected, so-called "minus 20" ballasts are
> specified.
What is this verbal diarrhea? You are just babbling on about nothing
at all. NONE of it is from a "practical standpoint". Moron.
> The only discharge lamps that I've ever seen flicker in cold temperatures
> are CFLs and unprotected or reduced-wattage ("watt miser") fluorescent types
> which have been mis-applied. Rarely, a high pressure mercury lamp will
> flicker due to a faulty arc tube and there's an odd type of high pressure
> sodium lamp designed to work on mercury ballasts that sometimes flickers
> near end-of-life. I've heard that high pressure sodium lamps operated on
> old series (constant-current) streetlighting systems will flicker; but, if
> so, all of the lamps on the circuit will flicker, not just one. I've never
> seen that phenomenon, however.
Great bunch of information all leading to the totally WRONG
conclusion. Never met a mercury vapor or sodium vapor lamp in person
did you? Hey, I've got one that lights my parking lot. And when it
gets cold and when it has lots of hours on it, the damn thing
flickers, Buster! I take it you came here to pontificate and show
everyone how much you know and all you did was show the world how
little practical knowledge you actually have.
It's simple. Streetlights these days are sodium vapor for economic
reasons. The one I've got produces an AMAZING amount of light for
consuming 35 watts. Street lights are somewhat though not extremely
larger. As they age the arc gets harder and harder to strike. Also as
it heats up the arc may not sustain leading to restarting. In this mix
there is also flickering as the gas pressure begins to creep out of
the stable arc range as the bulb ages. These conditions are much
exacerbated by low temperatures. Hence a lamp that was working fine in
warmer weather will suddenly turn cantankerous if the temperature
suddenly drops. And finally snow reflects the light making the
flickering much more obvious. And THAT kiddies is the real story about
flickering street lights. (Even if Terry has never seen it. Judging
from his bluster I take it he probably works for the government
designing street lights that flicker)
Proteus IIV
YOU SOUND VERY VERSED ON THE MATTER
DO YOU EVEN HAVE A LIFE OUTSIDE OF THIS GROUP ?
MY CONCLUSION AFTER SCANNING THE KNOWN SPECTRUM OF STREET LIGHTS IS
THAT HIS LOCALE HAS VERY CHEAP KNOCKOFF STREET LIGHTS AND HE SHOULD BE
CONTACTING HIS COMMUNITY LEADERS TO BRING THE LAME ASS CONTRACTOR THAT
INSTALLED THEM TO JUSTICE
OTHER THAN THAT STICK TO MOVIES AND SUCH BENJI
I AM PROTEUS
tadchem
You are lame.
Find the key just above the "Shift" key on the left side of your
keyboard.
It is usually labelled "Caps Lock".
Press it once.
Shut down your PC/laptop and then remove the key.
Do not restart your computer.
Tom Davidson
Richmond, VA
Jeff Waymouth
but one possibility has not been fully explored (although a previous
poster did come near to it). European power systems normally provide 50
Hz, instead of the US 60Hz, and, therefore, the roadway lighting systems
operate with that since electronic ballasts haven't penetrated that
market very much.
In my 20's and 30's, I could definitely see 50Hz flicker from HID
lighting (We had occasion to test European systems and used 50Hz power
to drive them) A previous poster noted that the snow on the ground
is a good reflective body and I think that characteristic could make the
50 Hz flicker more noticable.
Jeff Waymouth
lurch
<prote...@gmail.com> wrote:
>MY CONCLUSION AFTER SCANNING THE KNOWN SPECTRUM OF STREET LIGHTS IS
>THAT HIS LOCALE HAS VERY CHEAP KNOCKOFF STREET LIGHTS AND HE SHOULD BE
>CONTACTING HIS COMMUNITY LEADERS TO BRING THE LAME ASS CONTRACTOR THAT
>INSTALLED THEM TO JUSTICE
Where is that list of "knock off" makers at?
You're the idiot. That is about a silly claim.
"knock off" makers are not even in this channel. They are concerned
with bigger demographics. That is aside from the fact that you do not
even know how city planners go about choosing their street lights, much
less how they buy and install them.
Again, you're an idiot.
Steve Firth
> In my 20's and 30's, I could definitely see 50Hz flicker
<Cough>obblers.
bud--
> On Dec 22, 10:00 pm, "TKM" <non...@no.net> wrote:
>
> > From a practical standpoint, these days the only lamps that are sensitive to
> > cold temperatures down to ambient temperatures of about 0 F. (-18 C) are
> > fluorescent lamps. Even so, special fluorescent lamps are used routinely
> > at -20F (-29 C) in commercial freezers, outdoor signs and exterior building
> > lighting. High pressure sodium, high pressure mercury, metal halide, LED,
> > cold-cathode ("neon") and, of course, incandescent all work just fine. Low
> > pressure sodium lamps have a "thermos bottle" construction so they may just
> > take a little longer to warm up. Discharge lamps do require somewhat
> > higher voltages to initiate the arc at low temperatures, so in applications
> > where cold temperatures are expected, so-called "minus 20" ballasts are
> > specified.
>
> What is this verbal diarrhea? You are just babbling on about nothing
> at all. NONE of it is from a "practical standpoint". Moron.
>
TKM comes from sci.engr.lighting. He worked in the lighting industry.
His answer is typical of the long, technical answers from the very
sharp people on sci.engr.lighting. His "babbling" is all from a
"practical standpoint".
Victor Roberts
<tad...@comcast.net> wrote:
>On Dec 18, 7:21�pm, Eddie <du...@invalid.com> wrote:
>> In the UK we currently have cold winds and snow.
>>
>> A radio phone-in got a lot of people talking about flickering street
>> lights.
>>
>> Is there a real connection between bad weather and flickering street
>> lights. If so then how does it work?
>
>What kind of lammps do you have, carbon arc, sodium vapor, mercury
>vapor, incandescent, LEDs?
>
>It makes a difference.
>
>Vapor lamps are sensitive to the cold, as they require a narrow range
>of pressure internally to function. Cold reduces the presssure,
>making operation less reliable.
[snip]
As Terry said, cold ambient temperatures effect only
fluorescent lamps.
Fluorescent lamps operate at wall temperatures of 40C or
about 313K in a 25C ambient; and the mercury pressure is a
strong function of wall temperature. (The mercury pressure,
in turn, has a strong impact on the lamp's electrical
characteristics.)
Metal halide lamps operate at wall temperatures of about
1000C or about 1275K in a 25C ambient, while HPS lamps
operate at wall temperatures of about 1225C or 1500K. A
reduction of 40C in ambient temperature has a much greater
relative effect on the relatively low wall temperature of
fluorescent lamps than on the much higher wall temperature
of metal halide lamps or HPS lamps.
In metal halide lamps the mercury dose is fully vaporized
when the lamps are at operating temperature. Therefore,
even a moderate decrease in wall temperature can change the
lamp color, by reducing the metal halide pressure, but will
not significantly reduce the mercury pressure, so the
electrical characteristics will remain substantially
unchanged.
In HPS lamps the mercury and sodium are typically not fully
vaporized. A lower than normal wall temperature will
reduce the mercury and sodium pressures, and can impact the
electrical characteristics. However, the very high
temperature of arc tube makes even HPS lamps relatively
immune to changes in ambient temperature.
--
Vic Roberts
http://www.RobertsResearchInc.com
http://www.cflfacts.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.
This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission.
Michael A. Terrell
The first electricity in Middletown, Ohio was generated for one large
Carbon Arc light mounted on a tower. According to the town's history,
people cold read a newspaper over a mile from the tower. From there,
electricity was provided to the downtown area, then the suburbs. Later,
the system was sold to CG&E.
--
Offworld checks no longer accepted!
Martin
news:5be4j5t4579lr5d2i...@4ax.com...
> On Mon, 21 Dec 2009 17:58:39 -0800 (PST), tadchem
> <tad...@comcast.net> wrote:
>
>>On Dec 18, 7:21 pm, Eddie <du...@invalid.com> wrote:
>>> In the UK we currently have cold winds and snow.
>>>
>>> A radio phone-in got a lot of people talking about flickering street
>>> lights.
>>>
>>> Is there a real connection between bad weather and flickering street
>>> lights. If so then how does it work?
>>
>>What kind of lammps do you have, carbon arc, sodium vapor, mercury
>>vapor, incandescent, LEDs?
>>
>>It makes a difference.
>>
>>Vapor lamps are sensitive to the cold, as they require a narrow range
>>of pressure internally to function. Cold reduces the presssure,
>>making operation less reliable.
>
> [snip]
>
> As Terry said, cold ambient temperatures effect only
> fluorescent lamps.
>
> Fluorescent lamps operate at wall temperatures of 40C or
> about 313K in a 25C ambient; and the mercury pressure is a
> strong function of wall temperature. (The mercury pressure,
> in turn, has a strong impact on the lamp's electrical
> characteristics.)
I presume "wall temperature" is the temperature at the inside of the glass
tube right next to the glass.
> Metal halide lamps operate at wall temperatures of about
> 1000C or about 1275K in a 25C ambient, while HPS lamps
> operate at wall temperatures of about 1225C or 1500K.
I'd no idea that these lights operated at such high temperatures - even
hotter that an indcandescent light. I tend to think of discharge bulbs as
being "cold" compared with incandescent, but evidently this is not always
the case!
Andrew Gabriel
"Martin" <m...@privacy.net> writes:
> I'd no idea that these lights operated at such high temperatures - even
> hotter that an indcandescent light. I tend to think of discharge bulbs as
> being "cold" compared with incandescent, but evidently this is not always
> the case!
Incandescent lamp filament is about 2700K, which is quite a bit hotter
than these arc tubes.
When you switch off a HID lamp (mercury, sodium, ...) the electrodes
and arc tube are glowing bright red hot until they cool down.
Martin
> In article <m5-dnYGnD7e6wq_W...@brightview.co.uk>,
> "Martin" <m...@privacy.net> writes:
>> I'd no idea that these lights operated at such high temperatures - even
>> being "cold" compared with incandescent, but evidently this is not always
>> the case!
>
> Incandescent lamp filament is about 2700K, which is quite a bit hotter
> than these arc tubes.
Yes but the wall temperature (well, the outside wall, anyway!) isn't that
hot.
> When you switch off a HID lamp (mercury, sodium, ...) the electrodes
> and arc tube are glowing bright red hot until they cool down.
Are they? Didn't know that. How hot are the electrode tips for an arc light?
lurch
wrote:
>Jeff Waymouth <jfway...@comcast.net> wrote:
>
>> In my 20's and 30's, I could definitely see 50Hz flicker
>
><Cough>obblers.
On the Toad again...
lurch
(Andrew Gabriel) wrote:
>Incandescent lamp filament is about 2700K, which is quite a bit hotter
>than these arc tubes.
The color temperature of the light emitted, and the operating
temperature of the bulb are two entirely different and unrelated things.
Light bulb nomenclature, when referring to a temperature measured in
Kelvins, is referring to the light color temp, not the operating temp of
the bulb or filament.
Don Klipstein
With tungsten incandescent lamps, the filament temperature and the color
temperature of the emitted light are about the same. Color temperature
refers to the temperature of an ideal incandescent radiator (namely, a
"blackbody") producing light of the color temperature in question. The
color of light from incandescent tungsten is not much different from the
color of light from a blackbody at the same temperature.
- Don Klipstein (d...@misty.com)
Victor Roberts
The temperatures quoted are for the wall temperature of the
arc tube. The arc tube is contained in an outer bulb that
operates at much lower temperature.
lurch
I used to make a black body source that used a foot long calibrated
filament.
I used to make another that used coils of 'coiled' heater wire wrapped
around the ceramic 'wool' wrap and silica 'plaster of paris', then we
wrapped around the outside of that. The base form inside all of it was a
basketball. After the form set, we bake it in a kiln and after that,
with the actual excitation coils. Put a foot long ceramic feeder tube
onto that, and one "looks" into a perfect black body cavity.
Those were fun to slather together, and quite profitable too.
Archimedes' Lever
<lu...@yourangcousinitslibrary.org> wrote:
>On Thu, 24 Dec 2009 01:53:43 +0000 (UTC), d...@manx.misty.com (Don
>Klipstein) wrote:
>
>>In article <2he5j5htc221t98dm...@4ax.com>, lurch wrote:
>>>On Wed, 23 Dec 2009 20:01:42 +0000 (UTC), and...@cucumber.demon.co.uk
>>>(Andrew Gabriel) wrote:
>>>
>>>>Incandescent lamp filament is about 2700K, which is quite a bit hotter
>>>>than these arc tubes.
>>>
>>> The color temperature of the light emitted, and the operating
>>>temperature of the bulb are two entirely different and unrelated things.
>>>Light bulb nomenclature, when referring to a temperature measured in
>>>Kelvins, is referring to the light color temp, not the operating temp of
>>>the bulb or filament.
>>
>> With tungsten incandescent lamps, the filament temperature and the color
>>temperature of the emitted light are about the same. Color temperature
>>refers to the temperature of an ideal incandescent radiator (namely, a
>>"blackbody") producing light of the color temperature in question. The
>>color of light from incandescent tungsten is not much different from the
>>color of light from a blackbody at the same temperature.
>>
>> - Don Klipstein (d...@misty.com)
>
>
> I used to make a black body source that used a foot long calibrated
>filament.
The bulb the filament was in, not the actual filament. It was
vertical, and the excitation area was about an inch long and about 3mm
wide.
Nightjar
...
> In my case in South East England a cold snap was just starting and
> there was about 2 inches of snow and temperatures were a few degrees
> below freezing. The winds were unusally high for the area (perhaps
> VERY roughly 30 mph).
>
> It could just be coincidence but the radio callers got me thinking
> that maybe there's an electrical explanation. Any observations or
> ideas?
At the start of the cold period, my house lights and those of a friend,
both also in SE England, flickered a few times. I assumed the weather
was affecting overhead power lines somewhere, which resulted in
automatic switches having to transfer load.
Colin Bignell
Proteus IIV
<OneBigLe...@InfiniteSeries.Org> wrote:
> On Wed, 23 Dec 2009 19:42:06 -0800, lurch
>
>
>
>
>
> <lu...@yourangcousinitslibrary.org> wrote:
> >On Thu, 24 Dec 2009 01:53:43 +0000 (UTC), d...@manx.misty.com (Don
> >Klipstein) wrote:
>
> >>>On Wed, 23 Dec 2009 20:01:42 +0000 (UTC), and...@cucumber.demon.co.uk
> >>>(Andrew Gabriel) wrote:
>
> >>>>Incandescent lamp filament is about 2700K, which is quite a bit hotter
> >>>>than these arc tubes.
>
> >>> The color temperature of the light emitted, and the operating
> >>>temperature of the bulb are two entirely different and unrelated things.
> >>>Light bulb nomenclature, when referring to a temperature measured in
> >>>Kelvins, is referring to the light color temp, not the operating temp of
> >>>the bulb or filament.
>
> >> With tungsten incandescent lamps, the filament temperature and the color
> >>temperature of the emitted light are about the same. Color temperature
> >>refers to the temperature of an ideal incandescent radiator (namely, a
> >>"blackbody") producing light of the color temperature in question. The
> >>color of light from incandescent tungsten is not much different from the
> >>color of light from a blackbody at the same temperature.
>
> >> - Don Klipstein (d...@misty.com)
>
> > I used to make a black body source that used a foot long calibrated
> >filament.
>
> The bulb the filament was in, not the actual filament. It was
> vertical, and the excitation area was about an inch long and about 3mm
>
> - Show quoted text -
JUST LIKE YOU TROLL
USING INCHES MILLIMETERS AND EXCITATION IN THE SAME SENTENCE
YOU EROTIC HOMOPHOBIC FUCKTARD
I MAY NOT BE HUMAN BUT YOU ARE NOT A MAN
GET A LIFE AND HAVE A HAPPY HOLIDAY IF YOU CAN FREAK
OR BETTER FOR YOUR NEW YEAR RESOLUTION SHUIT UP AND DELETE YOURSELF
I AM PROTEUS
dh...@shawcross.ca
"Andrew Gabriel" <and...@cucumber.demon.co.uk> wrote in message
news:hgjc21$uh3$1...@news.eternal-september.org...
> In article <hgj98s$ija$1...@news.eternal-september.org>,
> "TKM" <nom...@no.net> writes:
>>
>> "James Sweet" <james...@gmail.com> wrote in message
>> news:hgj75t$jbj$1...@news.eternal-september.org...
>>> Eddie wrote:
>>>> In the UK we currently have cold winds and snow. A radio phone-in got a
>>>> lot of people talking about flickering street lights.
>>>>
>>>> Is there a real connection between bad weather and flickering street
>>>> lights. If so then how does it work?
>>>>
>>>
>>>
> --
> Andrew Gabriel
> [email address is not usable -- followup in the newsgroup]
dh...@shawcross.ca
"Andrew Gabriel" <and...@cucumber.demon.co.uk> wrote in message
news:hgmerr$rbn$1...@news.eternal-september.org...
> In article <6dxXm.99441$rE5....@newsfe08.iad>,
> <dh...@shawcross.ca> writes:
>>
>>
>> "Tzortzakakis Dimitrios" <no...@nospam.com> wrote in message
>> news:hglue7$dol$1...@mouse.otenet.gr...
>>>
>>> Demand is always almost equal to capacity. If it would be more, it would
>>> be a waste, if less there would be serious stability issues.
>> -----------------------------
>> Please check the definitions of demand and capacity - as the above is
>> nonsense.
>>
>> Ideally the capacity should exceed the demand by some optimal margin but
>> as
>> adding and dropping on line capacity is in blocks corresponding to the
>> capacity or rating of individual generators, and demand is up to the
>
> Most of the generators have variable power output, not simply on
> or off.
--------
In no way did I imply otherwise. However a generator is either on line or
off line as a unit so that the system "capacity" changes in blocks depending
on the rating of the machine added or removed from the system. The system
"demand" depends on the load and this demand is split between the units on
line- generally through some economic dispatch scheme.
>
>> customers (predictable but not controllable) the capacity will normally
>> exceed the demand by a fairly large margin at times- there is no
>> "stability"
>> problem. As for waste by having extra on-line generation- economic
>> dispatch
>> optimization is a common procedure.
>> If demand exceeds capacity, then problems can occur- not necessarily
>> stability problems.
>
> Frequency drops below nominal, and conversely when supply exceeds
> demand, frequency increases above normal. There's a requirement in
> the UK for frequency to average out correctly long-term (so things
> like synchronous clocks don't drift long-term), consequently,
> supply has to exactly match demand long-term. However, since the
> demand and supply can't exactly track each other short term due to
> inherent lags, there are periods of both demand exceeding supply,
> and supply exceeding demand. These are both inevitable due to the
> supply lag with different types of plant and unexpected plant
> failures on some occasions, and deliberately forced to correct for
> earlier drifts on other occasions.
--------------------
I am quite familiar with the concepts and practice involved.
-----------------
> There is contingency reserve in addition to the supply - additional
> plant spinning sychronous online ready when needed due to either an
> increase in demand or an unexpected loss of supply, and yet more
> plant offline ready to run up and cut in with a bit more notice.
------------------
Again I have no problem with this- this is normal . Possibly there are
some word usage problems
I take capacity as the total available generation on line That is,
(ignoring power factor as it affects unit capability), if there are 2- 100MW
units and a 50MW unit on line the capacity is 250MW . The load and losses
(again ignoring pf) may be 200MW leaving 50MW on-line reserve.
I take demand in this case as the load +losses 200MW which has to be
delivered to the system. Except for transient periods when loads change the
supply and demand are the same. Only during acceleration or deceleration
will they be unbalanced. Typically generator droops, essential to proper
load sharing between units, will result in speed changes. These lead to
frequency errors and the need to correct the long term average frequency.
-----------------------------------------
>
> A longer article I wrote on this some years back, with some examples
> of how it was applied in the UK to some specific historic events,
> and how it went wrong on one occasion...
> http://groups.google.co.uk/group/sci.engr.lighting/msg/99b03c9711a4f753?hl=en
>
>> As for the wind turbine reserve, you are being a bit over optimistic.
>> You
>> are assuming 30% availability of wind capacity. In practice, from recent
>> data it appears that 10-15% is a better figure and this is a statistic
>> based
>> on an annual average, which means nothing if wind fails. In other words.
>> reserve capacity must be available for the worst case situation- 100%
>> failure of any generation source, concentrated as in a 500MVA fossil
>> plant
>> or distributed as in 500-1MVA wind units in a region where wind diversity
>> is
>> small.
>
> The BBC did a programme about the wind power in Denmark, one of
> the highest users of wind power. In spite of installing lots of
> turbines and being able to point to all the power they get from them,
> they haven't been able to spin down any conventional generating
> station, because they need them when the wind stops. When the wind
> blows, they have an excess of conventional electricity which they
> sell, but for their neighbours, it's effectively as unreliable as
> the wind, since its export stops as soon as the wind stops, so it
> only commands a low price as an unreliable source. This combined
> with a failure of a transmission circuit, plunged much of central
> Europe into darkness a couple of years ago when supply suddenly
> fell well short of demand, and emergency load shedding was initiated.
> --
> Andrew Gabriel
> [email address is not usable -- followup in the newsgroup]
--------------------------
In my opinion, wind is to be used when available- reducing the load on other
sources at that time- but it doesn't replace the other sources for the good
reasons that you have given. The fact that wind energy is available on
nature's timetable, not man's, is one that many wind advocates appear to
ignore.
Derek Geldard
<"insertmysurnamehere> wrote:
>
>At the start of the cold period, my house lights and those of a friend,
>both also in SE England, flickered a few times. I assumed the weather
>was affecting overhead power lines somewhere, which resulted in
>automatic switches having to transfer load.
>
Doesn't that sort of thing happen when intermittent shorting or arcing
trips a breaker somewhere and the breaker makes automatic re-tries ?
Derek.
lurch
I would describe such events as a bit more than a flickering.
Tzortzakakis Dimitrios
? <dh...@shawcross.ca> ?????? ??? ??????
news:6dxXm.99441$rE5....@newsfe08.iad...
>
>
> "Tzortzakakis Dimitrios" <no...@nospam.com> wrote in message
> news:hglue7$dol$1...@mouse.otenet.gr...
>>
>> Demand is always almost equal to capacity. If it would be more, it would
>> be a waste, if less there would be serious stability issues.
> -----------------------------
> Please check the definitions of demand and capacity - as the above is
> nonsense.
>
> Ideally the capacity should exceed the demand by some optimal margin but
> as adding and dropping on line capacity is in blocks corresponding to the
> capacity or rating of individual generators, and demand is up to the
> exceed the demand by a fairly large margin at times- there is no
> "stability" problem. As for waste by having extra on-line generation-
> economic dispatch optimization is a common procedure.
> If demand exceeds capacity, then problems can occur- not necessarily
> stability problems.
> You are assuming 30% availability of wind capacity. In practice, from
> recent data it appears that 10-15% is a better figure and this is a
> statistic based on an annual average, which means nothing if wind fails.
> In other words. reserve capacity must be available for the worst case
> situation- 100% failure of any generation source, concentrated as in a
> 500MVA fossil plant or distributed as in 500-1MVA wind units in a region
> where wind diversity is small.
> -----
*plonk*
Steve Firth
> *plonk*
Excellent eco-weeny response there. Stick your fingers in your ears and
refuse to listen to hard fact.
Androcles
"Steve Firth" <%steve%@malloc.co.uk> wrote in message
news:1jbjo31.m7wc6b1nhllibN%%steve%@malloc.co.uk...
What would you expect from someone original enough
to give his name and address as noone@nospam?
Steve Firth
The refutation of his, and any windmill enthusiast's claim that windmill
are going to reduce CO2 emissions is to look at countries which have an
aggressive policy of installing windmills. Say Germany.
Compare Germany (lot so windmills) to France (very few windmills, lots
of nuclear power). Germany emits about 10 tonnes of CO2 per person per
year. France about 6.5 tonnes per person per year.
Similar levels of industrialisation, similar climates, similar
everything. What the Germans have found (surprise, surprise) is that
wind power is unreliable and must be supplemented by conventional
generating capacity.
The UK could meet all its Kyoto obligations by going nuclear to the same
extent as France. Politicians in the UK are too wet to go for it.
Androcles
British citizens nowadays carry drugs into China to get themselves
executed; they have good ol' Gaelic, Cymru or Anglo-Saxon
names like "Akmal Shaikh". I'm surprised Gordon Brown isn't
wearing a turban to get himself re-elected.
Steve Firth
> British citizens nowadays carry drugs into China
I know this is going to be hard for you to understand. But the use of
the plural in that phrase was inappropriate, and the use of "citizen" is
dubious. I think the term you were looking for was "subject", singular.
> to get themselves executed;
I think you will find his aim was to make lots of money, not to get
executed.
> they have good ol' Gaelic, Cymru or Anglo-Saxon
> names like "Akmal Shaikh".
As opposed to good old American names like "Nidal Malik Hasan",
"Mohammed Ali", "Barak Obama" or "Androcles" you mean?
> I'm surprised Gordon Brown isn't wearing a turban to get himself
> re-elected.
Turbans are worn by a very small proportion of the UK population,
notably Sikhs who are not Moslems and who are not even the majority in
the immigrant population. Your own coutnry appears to have an immigrant
population of about 250 million. So if you're one of those tossers who
bases their entire politics on the status of someone as "an immigrant"
then I suspect you'll have to start by hating yourself.
Oh look. You already do.
Steve Firth
> "Steve Firth" <%steve%@malloc.co.uk> wrote in message
> news:1jbjts3.11nbiav1h35ca4N%%steve%@malloc.co.uk...
> > Androcles <Headm...@Hogwarts.physics_q> wrote:
> >
> >> British citizens nowadays carry drugs into China
> >
> > I know this is going to be hard for you to understand. But the use of
> > the plural in that phrase was inappropriate, and the use of "citizen" is
> > dubious. I think the term you were looking for was "subject", singular.
> >
> I know this is going to be hard for you to understand, but Britain has
> citizens that are not subjects.
Mr Shaikh was a subject. Perhaps you should try to remember what you are
talking about?
I see you dodged away from the fact that he was an individual, not a
group. Is coping with the difference between singular and plural
something that confuses you?
daestrom
Sigh... too bad.
Don's quite right on the matter. 'Capacity' is not the current
production, but the current maximum possible by on-line equipment. So
it is always kept greater than demand. 'Production' is matched to
demand by a variety of techniques. Most notably, manual operation of
base load settings and governors of regulating units.
'Spinning reserve' is kept on line to respond to sudden losses in
capacity by a unit trip. Most system operators are required to maintain
enough spinning reserve available for the tripping/loss of the largest
generating unit. So if the system has a very large unit on line (say,
1000 MW), they must have at least that much spinning reserve. So you
could say the system has a 'capacity' that is kept 1000 MW higher than
demand.
daestrom
Steve Firth
> Oh look. You already have.
Shouldn't you be busy cutting holes in your bedsheet now?
BTW, only fuckwits piss about with follow-ups.
Archimedes' Lever
You are both fucking retarded.
UltimatePatriot
wrote:
> appears to have an immigrant
>population of about 250 million.
You're an idiot.
UltimatePatriot
wrote:
>Androcles <Headm...@Hogwarts.physics_q> wrote:
And only total retards piss and moan about the construction of a post
instead of the message posted.
You are one such total retard. In fact, you take the fucking cake,
retard boy.
Archimedes' Lever
wrote:
This is absolutely correct.
Androcles
"Archimedes' Lever" <OneBi...@InfiniteSeries.Org> wrote in message
news:oqinj597ppmoe9933...@4ax.com...
Sticks and stone may break my bones
but whips and chains excite me.
Proteus IIV
wrote:
> On Wed, 30 Dec 2009 15:56:01 -0500, daestrom <daest...@twcny.rr.com>
> wrote:
>
>
>
>
>
> >Tzortzakakis Dimitrios wrote:
> >> ? <d...@shawcross.ca> ?????? ??? ??????
>
> - Show quoted text -
YOU ARE AN IIDIOT
I AM PROTEUS
Nightjar
That would be the start of the sequence and, if the fault was transient,
it would result in the line being reconnected. However, if, say, a
line had been brought down, then the load would be shifted to minimise,
as far as possible, the area affected.
> I would describe such events as a bit more than a flickering.
They needn't be, unless you haappen to be within an area that ends up
disconnected as a result of the power switching. However, I do recall
one incident around 35 years ago, when a fault at a time of high demand
resulted in cascading overloads that blacked out much of SE England.
Colin Bignell
Tzortzakakis Dimitrios
� "Steve Firth" <%steve%@malloc.co.uk> ������ ��� ������
news:1jbjo31.m7wc6b1nhllibN%%steve%@malloc.co.uk...
>Please check the definitions of demand and capacity - as the above is
> nonsense.
>
me to read plain insults.
--
Tzortzakakis Dimitrios
major in electrical engineering
mechanized infantry reservist
hordad AT otenet DOT gr
Tzortzakakis Dimitrios
� "Androcles" <Headm...@Hogwarts.physics_q> ������ ��� ������
news:S6L_m.23186$pg4....@newsfe02.ams2...
almost nobody from any newsgroups have sent me a direct email (except a
couple of people), and I've been posting since 1999.
Tzortzakakis Dimitrios
? "daestrom" <daes...@twcny.rr.com> ?????? ??? ??????
news:hhgfr...@news6.newsguy.com...
I think it's installed power. I might be wrong, of course (since many people
seem to forget) I am greek and have gotten my degree in Greece. My English
is acceptable, but only God is always right.OTOH, we mere mortals...
> So it is always kept greater than demand. 'Production' is matched to
> demand by a variety of techniques. Most notably, manual operation of base
> load settings and governors of regulating units.
>
operate 24/7 at full load. When they need to reduce output at night, they
might eg reduce coal supply
> 'Spinning reserve' is kept on line to respond to sudden losses in capacity
> by a unit trip. Most system operators are required to maintain enough
> spinning reserve available for the tripping/loss of the largest generating
> unit. So if the system has a very large unit on line (say, 1000 MW), they
> must have at least that much spinning reserve. So you could say the
> system has a 'capacity' that is kept 1000 MW higher than demand.
>
mins. Even the (small) steam units, 3-4 hours and the 2-stroke diesels 1/2
an hour. I think hydro can synchronise in quite fast, too.
Steve Firth
> > Please check the definitions of demand and capacity - as the above is
> > nonsense.
> >
> This is an attack ad hominem.
No it's not. You don't appear to understand the term "ad hominem".
> I should check the definitions?
Yes. If you're going to pontificate about something which can be
measured objectively then you would do well to check your sources before
you start to talk about the subject. Otherwise you could end up looking
like someone who doesn't know what he's talking about. You were being
given good advice which you respond to like a child throwing a rattle
out of a pram.
> Nobody forces me to read plain insults.
No one posted an insult, plain or flowery. No one can force you to read
anything. You chose to read the post, you chose to flounce.
Archimedes' Lever
wrote:
>Tzortzakakis Dimitrios <no...@nospam.com> wrote:
"eco-weeny" and "nonsense". The first IS an ad hominem insult, and the
second is not, but is, however a mild insult.
Anyone anywhere in the entire world that uses the Thompson retard's
"weeny" moniker for anything, is himself a maturity "weeny", or an
immaturity champion, take your pick, asswipe.
daestrom
I thought this might be the root of the issue. You are normally quite
knowledgeable about such matters. I wondered why you went for 'plonk'
so quickly on Don's post.
>> So it is always kept greater than demand. 'Production' is matched to
>> demand by a variety of techniques. Most notably, manual operation of base
>> load settings and governors of regulating units.
>>
> As long as base units are synchronised, their most efficient use is to
> operate 24/7 at full load. When they need to reduce output at night, they
> might eg reduce coal supply
Although it might be the most economic operating point for a single
plant, demand of course does not change in such increments. So some
units operate as 'regulating units' and must 'throttle' their output to
match demand.
As Don pointed out, in a traditional system a technique called 'economic
dispatch' is used to decide which plants to control in this way.
Typically this works out to those with the highest fuel costs. Plants
with the lowest marginal cost are kept on line as long as possible as
demand drops, and those with higher marginal costs are the first to cut
back or be taken off completely.
Of course the choice to leave a plant on line at very low power or shut
it down completely is another issue. Cost / time to re-start, expected
schedule for re-start and fixed operating costs to name a considerations.
In an unregulated system, the choice is made simply on the bid price of
each generator (not counting long-term purchase agreements).
>> 'Spinning reserve' is kept on line to respond to sudden losses in capacity
>> by a unit trip. Most system operators are required to maintain enough
>> spinning reserve available for the tripping/loss of the largest generating
>> unit. So if the system has a very large unit on line (say, 1000 MW), they
>> must have at least that much spinning reserve. So you could say the
>> system has a 'capacity' that is kept 1000 MW higher than demand.
>>
> Here, in Crete, we have fast units (gas turbines) that synchronise in 11-12
> mins. Even the (small) steam units, 3-4 hours and the 2-stroke diesels 1/2
> an hour. I think hydro can synchronise in quite fast, too.
Yes, we have 'peaking plants' that can be remotely started and
auto-synch and load in a matter of minutes (gas turbine or diesel). And
some plants schedule up/down based on predictions of demand.
But if you've lost a large plant's output due to a trip, even 10 minutes
is too slow. Every moment that demand exceeds actual production means
frequency is dropping. So the combination of the on-line spinning
reserve units and the excess capacity in regulating units (sometimes
counted in the 'spinning reserve' summary) has to respond within seconds.
Here in the US the FERC (Federal Energy Regulatory Commission), along
with NERC, has specific guidelines / requirements to maintain a certain
level of reliability in the transmission system. This
daestrom
Androcles
>
> � "Androcles" <Headm...@Hogwarts.physics_q> ������ ��� ������
> news:S6L_m.23186$pg4....@newsfe02.ams2...
>>
>> "Steve Firth" <%steve%@malloc.co.uk> wrote in message
>> news:1jbjo31.m7wc6b1nhllibN%%steve%@malloc.co.uk...
>>> Tzortzakakis Dimitrios <no...@nospam.com> wrote:
>>>
>>>> *plonk*
>>>
>>> Excellent eco-weeny response there. Stick your fingers in your ears and
>>> refuse to listen to hard fact.
>>
>> What would you expect from someone original enough
>> to give his name and address as noone@nospam?
>>
> If you read my signature, at the bottom is my real email address. So far,
> almost nobody from any newsgroups have sent me a direct email (except a
> couple of people), and I've been posting since 1999.
>
Seems to me everyone and his dog uses sci.physics as
the default flaming and shit dumping ground.
Androcles
*plonk*
Do not reply to this generic message, it was automatically generated;
you have been kill-filed, either for being boringly stupid, repetitive,
unfunny, ineducable, repeatedly posting politics, religion or off-topic
subjects to a sci. newsgroup, attempting cheapskate free advertising
for profit, because you are a troll, because you responded to George
Hammond the complete fruit cake, simply insane or any combination
or permutation of the aforementioned reasons; any reply will go unread.
Boringly stupid is the most common cause of kill-filing, but because
this message is generic the other reasons have been included. You are
left to decide which is most applicable to you.
There is no appeal, I have despotic power over whom I will electronically
admit into my home and you do not qualify as a reasonable person I would
wish to converse with or even poke fun at. Some weirdoes are not kill-
filed, they amuse me and I retain them for their entertainment value
as I would any chicken with two heads, either one of which enables the
dumb bird to scratch dirt, step back, look down, step forward to the
same spot and repeat the process eternally.
This should not trouble you, many of those plonked find it a blessing
that they are not required to think and can persist in their bigotry
or crackpot theories without challenge.
You have the right to free speech, I have the right not to listen. The
kill-file will be cleared annually with spring cleaning or whenever I
purchase a new computer or hard drive.
Update: the last clearance was 25/12/09. Some individuals have been
restored to the list.
I'm fully aware that you may be so stupid as to reply, but the purpose
of this message is to encourage others to kill-file fuckwits like you.
I hope you find this explanation is satisfactory but even if you don't,
damnly my frank, I don't give a dear. Have a nice day and fuck off.
dh...@shawcross.ca
And how do you define demand and capacity? Please tell me.
I know the usual definitions of these as applied to a power system and these
don't coincide with your usage of the terms. Hence my statement which was
not intended to be personal.
I did not mean to insult you but it is true that I couldn't make sense out
of your statements- possibly it is a language usage problem.
--
-----
Don Kelly
cross out to reply
dh...@shawcross.ca
"Tzortzakakis Dimitrios" <no...@nospam.com> wrote in message
news:hhli2e$r4t$1...@mouse.otenet.gr...
------------------
That is rarely the most efficient situation. In Crete, it may be the best
approach because you may have some large fossil units and, apparently some
hydro and the rest is high fuel cost gas turbines and diesels so that it
is sensible. Since the 1930's the process of economic dispatch at any load
is to load all generators on line (where possible) to the point of equal
incremental cost per Kw modified for losses. This was first done
intuitively by operators and later proved to be the optimum loading
distribution. A further and more complex addition is to optimize unit
commitment considering the costs of shutdown and restart of units.
>> 'Spinning reserve' is kept on line to respond to sudden losses in
>> capacity by a unit trip. Most system operators are required to maintain
>> enough spinning reserve available for the tripping/loss of the largest
>> generating unit. So if the system has a very large unit on line (say,
>> 1000 MW), they must have at least that much spinning reserve. So you
>> could say the system has a 'capacity' that is kept 1000 MW higher than
>> demand.
>>
> Here, in Crete, we have fast units (gas turbines) that synchronise in
> 11-12 mins. Even the (small) steam units, 3-4 hours and the 2-stroke
> diesels 1/2 an hour. I think hydro can synchronise in quite fast, too.
-------------
That's right but if you lose a major generation, do you simply drop loads
and wait for more generation to come on line or do you have enough reserve
capacity in on-line units to pick up the load if, for example, the largest
unit on the system fails?
I would suggest that capacity is not installed power but the available
power that can be generated by the units which are on-line. If you bring up
and synchronize a100MW machine, you have then increased on-line capacity by
100MW.
Don Klipstein
I have known how you (via many nyms) like to resort to 5th-grade
name-calling in sci.electronics.design. As in calling people "retarded"
or "retards", and calling ideas "retarded".
And now you bring that sort of rubbish into the more genteel group
sci.engr.lighting?
Here, the harshest most-impolite phrase that I sense to play fairly well
in describing the $#!++iest piece of $#!+ is "stool specimen".
Heck, I have read about 98-99% of postings in sci.engr.lighting since
spring 1995, and I think yours is the first here since back then calling
people "fucking retarded". (Copied-pasted - I refuse to be the first
"regular" here to type such.)
Have a good day,
- Don Klipstein (d...@misty.com)
Archimedes' Lever
Klipstein) wrote:
> And now you bring that sort of rubbish into the more genteel group
>sci.engr.lighting?
Wrong, asswipe. I replied to a post. I do not trim groups, idiot.
Victor Roberts
As a regular, like Don, in sci.engr.lighting, I have read
many of the adolescent messages in this thread with disgust.
This news group has been a place for people to discuss
lighting technology in a civilized manner, without the kind
of demeaning references and trash talk you and others in
this thread have introduced.
I have not responded before, since I felt that ignoring you
would be the best way to make you disappear. I can solve my
personal problem with these messages by adding you and the
others to the Kill filter on my news reader, but that still
leaves sci.engr.lighting infected with your dribble when
others come here to ask a question.
If I knew which of the listed news groups you posted from, I
would have done the responsible thing and trimmed the groups
down to that single one for this reply. However, it is
clear you don't understand the concept.
Perhaps we should reconsider a Moderated group.
--
Vic Roberts
http://www.RobertsResearchInc.com
http://www.cflfacts.com
To reply via e-mail:
replace xxx with vdr in the Reply to: address
or use e-mail address listed at the Web site.
This information is provided for educational purposes only.
It may not be used in any publication or posted on any Web
site without written permission.
bud--
>
> As a regular, like Don, in sci.engr.lighting, I have read
> many of the adolescent messages in this thread with disgust.
> This news group has been a place for people to discuss
> lighting technology in a civilized manner, without the kind
> of demeaning references and trash talk you and others in
> this thread have introduced.
>
> I have not responded before, since I felt that ignoring you
> would be the best way to make you disappear. I can solve my
> personal problem with these messages by adding you and the
> others to the Kill filter on my news reader, but that still
> leaves sci.engr.lighting infected with your dribble when
> others come here to ask a question.
>
> If I knew which of the listed news groups you posted from, I
> would have done the responsible thing and trimmed the groups
> down to that single one for this reply. However, it is
> clear you don't understand the concept.
>
> Perhaps we should reconsider a Moderated group.
>
Archimedes' Lever probably comes to you courtesy of
alt.engineering.electrical - at least he infects that group (amongst
others). He has used at least 70 nyms (Ultimate Patriot is another)
and has earned the names of alwayswrong and dimbulb. His science-talk
is as useful as his trash-talk.
I have lurked at sci.engr.lightning and found it very enjoyable What
is remarkable is that you, and the relatively small group of regulars,
post at such a high level. The best discussions at
alt.engineering.electrical are routine discussions at
sci.engr.lignting. I personally would rather you just ignored
Archimedes.
This thread has also managed to dis Don Kelly. But that reflects on
Tzortzkakis, not Don. Don is as competent as anyone at
alt.engineering.electrical, and has contributed a lot of very
interesting information.
I hope you don't filter google-groups - my regular news source doesn't
permit some crossposting.
But with threads like this, I wonder if crossposting is ever useful.
--
bud--
Archimedes' Lever
<x...@lighting-research.com> wrote:
>As a regular, like Don, in sci.engr.lighting, I have read
>many of the adolescent messages in this thread with disgust.
>This news group has been a place for people to discuss
>lighting technology in a civilized manner, without the kind
>of demeaning references and trash talk you and others in
>this thread have introduced.
Then FIND the OP (original Poster) and chastise THAT TOTAL RETARD for
cross-posting it into a group read by immature assholes, and assholes
like me that point out their immaturity.