Exploding Transformers

The first video is a downed power distribution line arcing to ground. The clip is mislabeled, since there is no transformer exploding. A downed power line often creates a molten mixture of soil and rock, called a clinker, that can be tens or hundreds of feet long before the power company finally kills power.

For information on the second video, see our site at:

There are other "interesting" events on that page as well... :^)

Bert

Simple traffic accident dropped a phase off the pole that was centered in the video. The downed power line is clearly visible, and the commentary from the 'kid' indicates that a traffic accident where the pole across the street was struck caused the fault.

Nothing unusual, IMHO, and the power level of the arcing was probably about the normal demand, hence the failure of the fuses/circuit breakers to open the circuit is not unexpected.

I doubt they posted this, it appears to be totally amature video. But a reasonably good video of a big oil fire. Personally, I'd have been getting my butt out of Dodge instead of making that video!

Then again, about 2 zillion people will disagree with me!

I witnessed a similar one, where a trailer-type dump truck pulled forward while its bed was still raised and caught a 6KV overhead line. Some amazing "lightning" displays. A neighbor got out his garden hose and was spraying down burning weeds in the easement... fortunately I was able to get him to stop; and run ;-)

...Jim Thompson

Been in similar situations in Florida after storms... People who think they can grab a tree branch that blew down and push a sizzling conductor off their driveway...

"You do know that green wood conducts rather well, don't you? "

"Mind your own business..."

"OK, bye..." (and watching from a distance. He thought for a while, tossed the stick, and walked away.)

In 1962 I rented a house that had radiant heat (resistive wire buried in the ceiling plaster).

Nice, except the sub-panel for this stuff was hard-wired direct to the entrance drop, rather than through the main breaker.

A neighbor's sub-panel shorted out and caught fire, blowing copper, etc, into his back yard, so he started spraying it with a garden hose.

I also managed to stop him before he killed himself.

...Jim Thompson

Time to send in a technician with a bucket of water:-)

Not to mention the wet bark. ;-)

Cheers! Rich

I live in the city, things are very close together.

A few years ago I saw lightning hit a pole pig and blow it clear off the pole. You could see the feeders arcing away until there was a long enough current draw to cause the breakers to trip.

They found the blackened transformer about a half mile away.

That's a pretty good analysis of the fault. Typically, the protection coordination is designed such that through faults (faults downstream of the transformer where the transformer conducts the fault current) are cleared before the transformer is damaged. However, in this case, the protection failed (passively) some time before this event. So the fault was not cleared.

This illustrates a problem I've seen at a number of utilities (and industrial facilities). The systems have too many passive failure modes in their designs. The philosophy tends to be "save money on the initial design, we'll catch the problems in the maintenance cycle". Then, they cut the maintenance budget.