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The most danderous job on Earth.......


Tony
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Tony i work for national grid in 400,000, 275,000 and 132,000 volt substations, live line maintenance was being looked at for us but then they decided it wasn't practical. Luckily i avoid working on the pylons and the highest i go is probably 60-70ft in a cherry picker. 

 

Its hard to get your head round it but that guy is perfectly safe up there as-long as he doesn't touch any of the phases or somehow short the phase to earth. Not for the faint hearted thou thats for sure. Im also not convinced that being charged up to that sort of voltage will do you any long term good. Sometimes at work i will be doing maintenance on a piece of equipment next to a live circuit and you can feel your body pulsing from the induced voltages and your hair standing up all over your body. We have a few substations around near you, Radlet, Bushey and Watford. 

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I have been doing it 8 years and on maintenance work its good but now its more about monitoring the equipment. It is very rewarding work when you go from an empty circuit bay with worn out equipment to brand new equipment all tested and ready in a couple of weeks. I get to work on equipment built during Britain heyday of engineering in the 60's and 70's. Amazing bits of equipment and very impressive in its operation. Refurbishing these bits of equipment to extend its life for another 15 or so year is good fun as well. 

 

Working in a substation is pretty safe, im still scared of the equipment which always means im very cautious which is exactly the right attitude to have. No one wants to go home in a box at the end of the day and all the staff look after eachother. The safety culture is ingrained in everything we have to do.

 

This is the sort of stuff we maintain (TURN SPEAKERS DOWN!)

 

http://www.youtube.com/watch?v=moN8HZOa5FA

 

http://www.youtube.com/watch?v=SxVa1gpdfg8

 

http://www.youtube.com/watch?v=Egs8ZGZb4NM

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 Do you wear a Fairiday suit < crap spelling sorry.

 

'the mind boggles. I have never thought of Michael Faraday as a "fairy".  He had four kids and started his working life as a blacksmith - but then he did say â€œWithin the laws of Nature, nothing is too wonderful to be true.†

 

:)  :)  :)  :)  :) 

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Nah we don't have to wear any special type of suit. Unlike the guys in the video you posted we only work on stuff when its dead and even then we apply earths to remove any induced voltages on the equipment. The equipment has to be designed to be safe but we do have failures every now and then. We had one recently at elstree where a piece of equipment manufactured in the 1950's exploded into lots of pieces. Luckily no one was nearby and we repaired it and put it back in service. Its the same type of circuit breaker as in the first video i posted. Amazing really when you think about it being left outside for 60 years for the elements to eat away at it but when called upon to operate they still works. Goes to show how well we used to build stuff back in the day!.

 

The new stuff is cheap and flimsy, hate working on it as everything is built to be "just good enough".

 

One thing that still makes me nervous is taking oil samples out of a transformer when its onload, its humming away with 400,000 volts running through it and your standing a foot away from it. The thing is thou these transformers last 50 years and the monitoring we do ensures that any problems with it internally show up years before it could fail in service.

 

I love the job, the banter is great.... it beats working at Tesco!

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For a short time in the 1970's (while she was still a sixth former) my daughter worked in the high voltage laboratory at the English Electric Company at Stafford where they made this kind of equipment. She claimed that it was pretty exciting stuff - please excuse the pun.

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For a short time in the 1970's (while she was still a sixth former) my daughter worked in the high voltage laboratory at the English Electric Company at Stafford where they made this kind of equipment. She claimed that it was pretty exciting stuff - please excuse the pun.

 

It's a shame all of that sort of in house research is long gone... Germany is the solution for every countries HV needs nowdays :o( . I have been to Stafford (Alstrom. Areva) and seen them constructing HV transformers. It is quite a sight to see especially when a new one costs £4 million quid. Some of them now weigh 300 odd tonnes at their transport weight. 

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Very true Tony. Got a phonecall of Friday about a fault on one of our circuits.

 

Overhead line had come down whilst people were on site. One of lads saw the circuit breaker operate and a huge flash, 10 seconds later the circuit breaker closed and then tripped open again. Next thing they know members of public have reported that a line has come down and the tree is on fire. It probably only short circuit for 100ms but 1000 amps at 275000 doesn't take long to fry something. Big investigation to find out why it happened now. 

 

For the last two weeks ive been doing surveys on our transformers to check for anything strange or abnormal on them

 

IMAG0156_zpsdshraj0r.jpg

 

IR_2013-12-04_0246_zpsfe5bc33d.jpg

 

We use a thermal camera to check the conductors for what we call hot joints where two pieces of conductor join, this is a perfect example of a fault. Corrosion gets into the joint and causes a high resistance. With that resistance it builds up more heat. It will have to be stripped down at some point and reassembled and then it should go back to normal temperature.

 

I have to admit i was tempted to take the camera to Snetterton yesterday and get a cool picture of glowing brake discs! At 40K a camera thou i would be in the s**t if anything happened!

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We only tend to use 3 metals.

 

-Copper was used in the past and seems to normally be problem free but since the price has gone up so massively new installations don't use it

-Aluminium is now what everything is made out of and its what the joint in the photo is made of. It is a pain to clean it up to get a good connection hence why this one is hot. The busbars are larger with aluminium as its not as good a conductor as copper . Benefits are cheap and its lightweight

- Brass. We only really use brass when making a joint between copper and aluminium, its just there to stop a reaction between the two metals.

 

The transformer in the photo supplies network rail, it has a cable that runs from Elstree to Bushey Arches where it then feeds the railway. In terms of the amount of electricity flowing through it its minimal compared to some of the equipment we have. 

 

Interesting website which shows the breakdown of generation and it shows how wind generates hardly any electricity compared to coal, nuclear etc.

 

http://www.gridwatch.templar.co.uk/

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Copper and aluminium are pretty much all that i have seen used, good conductor of electricity and also strong enough to not sag or bend over quite long lengths. The busbars are also hollow, there is something called the skin effect which means electricity flows around the outside of the conductor so making them solid is a waste of time and money. Good job as well because copper weighs a ton and trying to work with solid ones would make my job alot harder.

 

The only issue we sometimes have with copper is that when you make a connection you have to "tin" the end of the bar which is basically a material we paint onto the bar and then heat up using oxy acetylene. It gets to a certain temperature and you wipe it off and it leaves a nice shiny silver type finish. This is ideal for making joints as it wont turn green like copper does when left in the elements.

 

http://www.youtube.com/watch?v=bdMOWEUgWQY

 

This video shows someone from our company (i don't know who) Working on a piece of dead equipment that is picking up voltage from nearby circuits. This person is a plonker because the earth he is using drawing the arc shouldn't be applied by hand it should be done using insulated tools. I did msg him through youtube but he hasn't learnt his lesson it seems! He even shocks himself in the video! Im glad no one in the team i work with is like that!

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  • 1 month later...

Thought you might be interested in this Tony, one of our super grid transformers on load in north london. The only part of the job that un nerves me is standing next to a tank full of 100,000 litres of transformer oil with 275kv inside it.

 

 

And what one looks like when it goes bang!

 

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Its a refined mineral oil, once it has been used on transformers it gets reused in cosmetic products believe it or not! Alot of the older oil contains PCB's which were added to prevent fires but is very bad for humans. The PCB's get in your skin and once its got in your system your body cant get rid of it. Over the years the levels will build up and up if you don't use the correct protection. 

 

Luckily most equipment has had the PCB's removed from the oil making it alot safer. 

 

Transformers are efficient but only to a certain extent. Say a transformer was 99% efficient then most of the 1% loss would be through heat which is why most transformers have some sort of cooling on them. Sound would be one of the energy losses through the transformer. The forces on the two sets of winding causes a vibration of the internal components which is why you get the humming. In my experience the harder the transformer is working the worse the humming gets. I can often remember as a kid going into lee valley park just down the road from me and hearing the supergrid transformers at waltham cross substation humming away. The substation was over a mile away but you couldn't mistake the humming. Never thought i would end up working there thou! Those transformers were replaced in the late 90's because during there 30 year life they had taken an absolute battering trying to supply london. The newer transformers were uprated and the noise massively reduced.

 

As for the water as the means of fire fighting, if you see the video i posted there is red pipe work everywhere, that is the fire deluge system which is designed to prevent a major transformer fire. It uses 1000's of litres of water but is sprayed as a fine mist which suffocates the fire rather than making it worse. The video of the transformer on fire, well that could be anyones guess because i doubt the equipment was even isolated which just adds the danger. You would assume they knew what they were doing but i wouldn't be that close to the fire.

 

 

This is one of ours that expired last year

 

http://www.hulldailymail.co.uk/Huge-electricity-substation-Cottingham-Beverley/story-18814388-detail/story.html

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No problem Tony, i thought it was a crazy idea when i first saw it. Like putting water on a chip pan fire!. We have had the fire equipment go off by accident before but it is designed in such a way that it shouldn't cause the transformer any problems whilst it is going off. Was an impressive sight thou!

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Systems of this kind have been in use for a long time. When I worked at Mather and Platt around 1950 we produced a system known as Mulsifyer which had been around since the 1930s. We had a demonstration rig in the factory yard and it would put out a fiercely blazing oil fire in seconds.  There is some historical information here

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Systems of this kind have been in use for a long time. When I worked at Mather and Platt around 1950 we produced a system known as Mulsifyer which had been around since the 1930s. We had a demonstration rig in the factory yard and it would put out a fiercely blazing oil fire in seconds.  There is some historical information here

 

Cheers for that, didn't realise it had been about so long. Would be interesting to see a video of it actually trying to deal with a transformer fire.

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