Should the OHLE be arcing in light drizzle?

[PaxVobiscum]

..or even at all?

Waiting for a train last night at a certain Glasgow Station, passengers were entertained by a small but noticeable son et lumière from a vertical insulator at the end of the platform. Intermittent fizzing and yellow/orange flashes (is pigeon poo rich in sodium?) Is it worth reporting, or does this sort of thing happen all the time?
I tried to take a picture on my phone but was somehow reluctant to get near enough to get a good shot.

 

[DarloRich]

it might be nothing but I would call it in anyway of you are concerned.

 

[AM9]

..or even at all?

Waiting for a train last night at a certain Glasgow Station, passengers were entertained by a small but noticeable son et lumière from a vertical insulator at the end of the platform. Intermittent fizzing and yellow/orange flashes (is pigeon poo rich in sodium?) Is it worth reporting, or does this sort of thing happen all the time?
I tried to take a picture on my phone but was somehow reluctant to get near enough to get a good shot.

Its not uncommon for insulators on all high voltage lines to buzz, fizzle and sometimes have small flashovers. If it gets large enough to see sparks of glowing metal come to ground then there may be a problem. Are they as big as when a pantograph flashes in frost?

 

[carriageline]

I have never seen OHL have a flashover, and there's plenty of it out my window! It does fizz and buzz in the rain which is eerie!

If i saw it at work, I would report it.


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[Bald Rick]

If it is arcing across the insulator, it is unusual and a likely future insulator failure. So report it. It may well have been bird related.

Just buzzing is not an issue.

If it is arcing between contact wire and the pantograph when a train passes underneath the insulator, this is nothing to worry about.

 

[edwin_m]

If you report it, it would be worth quoting the letters/numbers on the plate on the nearest pole if you know them. That will give them a definite confirmation of where any problem might be.

 

[carriageline]

Or, the better thing, would be to inform a member of station staff who SHOULD be 'in the know' of who to contact.


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[table38]

If it's doing this, then report it

[youtube]FivDcIHfguU[/youtube]

 

[Muzer]

I've seen a dull blue glow during night-time drizzle on the south end of the ECML, but nothing more than that.

 

[mattyoung905]

Yesterday I saw an arcing over of an insulator to a support at a local station: Orange sparks flashing over a few times a minute - got a little bit of flame at one point too. Mentioned it to a member of platform staff who agreed it didn't look too bad but was out of ordinary so he'd get it reported.

 

[PaxVobiscum]

While waiting at Bellgrove today I was aware of a number of birds flying about the entrance to the tunnel under the old abbatoir, and had just stopped looking in that direction when there was a very loud explosion, a sudden cloud of smoke and feathers and no more pigeons. Nothing tripped and the trains carried on.

Not so much RIP as I squared R

 

[NSEFAN]

Not so much RIP as I squared R

Very good!

 

[AM9]

Very good!

Watts that about?

 

[edwin_m]

Resistance is futile!

The power may have been tripped by the pigeon demisal event, but standard practice is to try once to re-close the breaker if there is no other indication of a problem. So the power may have been off but only for a few seconds.

 

[DaveHarries]

Can we put an end to these "shocking" puns please? If not then I will pylon the pressure.

Dave

 

[PaxVobiscum]

We have a mast a fine collection now - a step up from the usual. We could conduct ourselves with dignity and stop now without losing phase.
We really auto tranform this in to a serious discussion again before the thread gets isolated.

 

[edwin_m]

Did someone dropper clanger? It didn't register with me, but I suppose we will all copper penalty from the moderators if the current situation continues. We should agan try to be reasonable.

 

[SpacePhoenix]

What's the current news? @edwin, amping about?

 

[edwin_m]

What's the current news? @edwin, amping about?

No, just re-volting.

 

[Elecman]

I'm sure an Uncommanded OLE trip requires a wait of 2 mins by the ECR Controller before trying to reclose the breaker to give time for any phone calls re persons in contact with the OLE

 

[edwin_m]

I'm sure an Uncommanded OLE trip requires a wait of 2 mins by the ECR Controller before trying to reclose the breaker to give time for any phone calls re persons in contact with the OLE

This report, which admittedly is from HS1, says that the breakers will automatically attempt to re-close after a few seconds. I'm not sure if they all do this, but it would explain why the controller shouldn't re-close them manually without seeking further information, as one re-closure attempt has already failed.

http://www.raib.gov.uk/publications/investigation_reports/reports_2010/report122010.cfm

 

[carriageline]

On 3rd rail at least, they will try to close it nearly straight away. If that fails they will wait a minute or 2. The idea being to get it reenergised within a few minutes, thus stops distracting phone calls from signallers! They can try up to 3 times (2 times on a single end fed section)

 

[DelayRepay]

Resistance is futile!

Ohm y goodness.

 

[Ian1000]

Some small sparks / orange glows on insulators is not something to be worried about. Insulators are designed in the knowledge that pollution will be deposited on their surface. By the coast this could be salty, clearly there could be diesel particulate and other sources such as bird droppings! When this pollution gets wet - light rain / fog are particularly bad, it becomes conductive. Something called dry band arcing then occurs, the conductive layer heating up with liquid evaporating. When the liquid evaporates, you get localised arcs such as those described. Generally nothing to worry about and if the insulators are ceramic they will do no long term damage.

 

[cjmillsnun]

Some small sparks / orange glows on insulators is not something to be worried about. Insulators are designed in the knowledge that pollution will be deposited on their surface. By the coast this could be salty, clearly there could be diesel particulate and other sources such as bird droppings! When this pollution gets wet - light rain / fog are particularly bad, it becomes conductive. Something called dry band arcing then occurs, the conductive layer heating up with liquid evaporating. When the liquid evaporates, you get localised arcs such as those described. Generally nothing to worry about and if the insulators are ceramic they will do no long term damage.

Hmmmm

Dry band arcing is a result of pollution, but on composite insulators, it is definitely not a good thing, as it can degrade the insulator which could eventually cause flashover.

 

[Ian1000]

Exactly why I said no issue for ceramics. Dry band arcing is unavoidable for composites as well, there is nothing you can do to avoid it completely. Yes, it will cause damage over a long period and the benefits of the extra hydrophobicity that the composites have / the lower weight has to be set against probable increased ageing.

 

[iantommo]

I'll bet this put the willies up the footplate crew
https://www.youtube.com/watch?v=vQTinmPjS_o