Arny Krueger said:
Been there, seen that, from a few blocks away. The boom was audible and
the fire was visible from that distance.
The old transformer in my back yard smoked for several hours, but neither
exploded nor emitted flames. The replacements were appreciably larger!
Yes, most pole transformers are filled with some kind of insulating,
heat-transferring oily liquid. It may contain nifty stuff like PCBs,
though hopefully those have all been removed.
There's a reason why they don't put these things in people's houses!
In fact oil-filled transformers are commonly put in dedicated rooms in
commercial buildings, but they have appropriate design and safety
features.
We had a transformer blow in a local substation, and had rotating
blackouts for about a week. It was about the size of a small house, and
the replacement had to be trucked in from out of state.
Many years ago, I was hanging out of the bedroom window at 2am, watching a
spectacular thunderstorm that had been raging, and circling round my
location, for an hour or so. About 200yds up the road, where it ran out to a
dirt track, and no houses were yet built, was a pole, with a tranny on it
that I would guess to have been perhaps 3ft x 2ft x 2ft. It fed just the
farm in the field behind my house.
I was looking straight up the road, when the pole took what looked like a
direct hit. It probably actually wasn't direct, as I guess that would have
just vapourised the whole thing, but close enough anyway, that there was no
discernible delay between the stroke flash, and the bang, which was so loud
that I thought the vibration was going to bring the house down around me.
Anyway, as I continued to watch, half blinded, an orange glow like a plasma
ball started to grow around the top of the pole. It expanded out until it
looked the size of a small weather balloon, then just hung there for several
seconds. Then, without warning, the top of the pole - presumably the
transformer - just exploded with a huge bang, a sheet of flame, and a shower
of sparks. The orange ball was immediately dissipated. When I was able to
look again, the top of the pole was on fire. The whole street was without
power for 3 days.
When I went to look at the pole the next morning, there was just a charred
stump at the top. What was left of the tranny was on the ground, and of
course, the lines were down, but oddly intact, as they hung on the next pole
out across the field. The tranny was three phase 11kv to 240v I think. Three
lines plus one across the top, anyway. I don't know how much of this
pyrotechnic display was as a result of the 11kv, or of megavolts getting in
there from the lightning strike, but whichever, it was one of the most
spectacular things that I've ever seen.
I now live in a house further up the same road, and the pole and tranny were
moved from the roadside to the bottom of my neighbour's garden. A couple of
years back, the electricity company put in a new underground feed to the
farm, and came and took the overhead down. My neighbour asked them to leave
the pole, as he has a rather nice Russian Ivy growing up it, that is like a
huge bush, or tree even. Curiously, when the tranny was in place, the ivy
never grew closer than a foot or so to the platform where it was mounted.
Since it's gone, the ivy now grows right to the top, so obviously, plants
can sense the field around the high voltage components, and don't like it.
Makes you wonder whether there's anything in these claims that high voltage
overheads cause cancer in kids ...
Arfa
.