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?
Tea.
Last night we had lightning, not flickering street lights -- and there 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.
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?
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.
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.
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.
Because of utility privatisation they don't service the lights, exchanging blown bulbs with fresh ones?
Heh. I remember him. Alan Beswick was another local radio hero...
Mike P
that wasn't helpful at all.
/BAH
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.
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
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.
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.
Description too devoid of information to even guess on the cause. They could each be describing something completely different.
If the streetlamps have their own didicated overhead supply (now very rare in the UK), then maybe that's arcing somewhere in the wind.
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!
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.
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.
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
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