"Mr. Man-wai Chang" writes:

A small town's sudden power surge fried tech gear in hundreds of homes

Full story:
http://www.foxnews.com/tech/2017/01/...eds-homes.html


Residents in the small Pennsylvania town of Brookville must've wondered
what on earth was going on earlier this month when a sudden power surge
caused electrical appliances and gizmos in up to 1,000 homes to fry,
explode, or simply conk out.

What may have momentarily seemed like some kind of weird supernatural
happening was actually an electrical surge caused by a failed power line
component, according to an AP report. Local media said that "damage
ranged from residents losing a refrigerator to losing all appliances in
the kitchen or losing everything in the house."

Interesting how a failed insulator could have caused this. How often are
distribution circuits of different voltages connected together but
separated by only a single insulator?

Up the street from me, they upgraded a MV distribution circuit from a lower
voltage to a higher one (13,800V I believe). But a portion of it they
decided to leave at the lower voltage, probably because there are a bunch
of pad-mounted transformers feeding businesses there they didn't want to
replace. They decided to feed that section from the far end through a
bank of transformers, but where that section was once connected to the
now upgraded section, they put in multiple breaks so that a single failed
insulator or a lineman doing the wrong thing won't connect the two
circuits. An underground feeder had its fuses removed, wires connecting
the fuse holders were removed and the line from the pole with the
underground feeder to the next pole had insulators spliced in the middle.
At least 3 breaks.

I've also seen the results of that type of surge. The top of a pole broke
in a storm and the 4800V MV distribution wires made contact with the
120V/240V feed to houses. Two of them burned to the ground.