Heathrow power outage 2

[Hoxton123]

Heathrow Airport closed all day after nearby fire causes power outage - live updates

Flights are cancelled and diverted mid-air as Europe's busiest airport closes until midnight over a "significant power outage".

www.bbc.co.uk

i do now know what the substation voltages are, but one of the two transformers is completely burnt, and i guess they isolated the substation in order to fight the fire

 

[Alistair_Heaton]

Scottish political aviation humour...

 

[oldrunner]

Maybe some of the sparkies here can help, but it loks to me,from what I've been able to clean, is that these two TX are the A and B 275kV. The third on the right looks like an add on for local power distribution.

For street view it looks very much to me like there are no fire walls between these two. Is that normal? Bearing in mind this substation might be 50 years old.

Any other comments on spacing or design?

View attachment 6947

The latest ASCE 113 Substation Design Practice Manual has a chapter on different kinds of protection walls for collateral damage from explosions. Also most current transformers are designed for the cover to explode upward before the side wall panels.

 

[davidbeach]

And with decent protection you detect the fault and clear the transformer long before it gets to the interesting stage.

 

[electricuwe]

Fully agree to thermionic1. Askarel/PCB was by far more a curse than a benefit in regard to safety. But there are other fluids where at least no sever health or environmental risks are known although they are in use for several decades. I have worked on units of several 10 MVA using silicone oil thirty years ago.

 

[waross]

Fully agree to thermionic1. Askarel/PCB was by far more a curse than a benefit in regard to safety.

Public hysteria.
Years ago, during the initial concerns about DDT, the public became aware of "Bio-degradability".
Almost every month the "Bio-degradability" of another potential contaminant was reported.
PCBs were/are very stable and do not degrade for centuries. The key is "Very stable". When PCBs were released, they found the lowest level and just sat there.
PCBs were heavier that water and so would just pool in the low spots of water bodies and then do basically nothing.

Then it was announced that PCBs were SLIGHTLY carcinogenic.
Wow. Carcinogenic and it's forever.
I was working at a plant that had about two millions of gallons of used oil that was contaminated with PCBs.
I was concerned.
A friend of mine was a chemistry PhD and head of NMR services at a large university.
All research departments sent samples to his department for analysis.
He was responsible for knowing the relative hazards and safe handling procedures for any substance submitted to his department.
He often interacted with the cancer researchers.
He was warned that some samples were so active that one drop on unprotected skin posed a 100% chance of skin cancer.
His advice:
The cancer hazard from PCBs is so slight that if you smoke, you have nothing to worry about from PCBs.
But beware of heavy oils.
Heavy oils are extremely carcinogenic.
The real cancer hazard was the two millions. gallons of used oil, not the 100 PPM of PCBs.

[Ironic Anecdote Alert]
A truck was transporting an old transformer on an Ontario highway.
The transformer was leaking PCB coolant.
A family was following in their car and over the miles their car was sprinkled with PCB coolant.
The family was given a replacement car. I don't know how the contaminated car was disposed of.
Miles of highway was repaved. I don't know how the contaminated asphalt was disposed.
Public Hysteria and misunderstanding versus science.
Public Hysteria wins every time.
Conventional transformer oil is slightly carcinogenic. Probably more so than the PCB coolants that it replaced.
Perception, misunderstanding and hysteria.

[Ironic Anecdote Alert2]
A number of a rancher's heifers gave birth to deformed calves.
Someone remembered that a capacitor station 10 or 20 miles away, had buried some PCB insulated capacitors some years before.
The burial sites were excavated and it was found that the capacitor cases were intact and there had been no leaks.
The investigation continued.
It was discovered that there had been an accident at a logging site the winter before.
A valve was knocked off of a diesel fuel storage tank and about 1000 gallons of fuel was spilled.
The ground was frozen and the fuel flowed on the surface until it found a small creek.
The creek was the source of drinking water for the ranchers cattle.
Diesel fuel is a strong mutagen.
The moral?
There are lots of things in regular use and to which many persons are regularly exposed that are far worse than Poly-Chlorinated-Biphenols.

I suggest that the repaving created several thousand times the cancer hazard that was posed by the original sprinkles of PCB.