On Mar 29, 9:55*pm, David Nebenzahl wrote:
The other night our power went out here in Oakland. Was watching teevee
when the lights went out all of a sudden. Then they came back on. Then
they flickered a bit and went out again. Came on again, there was a
muffled "BOOM!", whereupon they went out, this time for good.

It was the first power outage we'd had here in a long time. And I
noticed some really strange things.

First of all, the "BOOM!" turned out to be a transformer which exploded
rather spectacularly right outside the building I'm in. Some neighbors
down the street said they actually saw the thing go, sparks and all.

Turns out there were several other transformers all over town that blew
at (about) the same time. Power was out to 4,500 customers at the peak
of the outage, in an area covering many square miles. But walking
around, I'd see blocks on end without power and with no streetlights.
Then there'd be a block with power. And some of the blacked-out areas
had working streetlights. The local power grid must be a crazy quilt of
wiring.

Regarding the cause of the outage, when I got ahold of PG&E (Pure Greed
and Extortion), the guy said it was due to "equipment failure". Talking
with my neighbor, though, he said he though it was human error: someone
threw the wrong switch or something.

And really, how else could a transformer fail spectacularly, other than
an overload, except by there being some kind of massive overvoltage
surge (what people incorrectly call a "power surge")?

OK, so for the rest of the evening we were without lights. Sort of.

Sort of? I though power outages were pretty much black and white: either
the power is on or it's off.

Not so, grasshopper. I stuck my VOM into an outlet and monitored the
line voltage. The reason I did this was that after the power had been
off for a good long time, I heard my microwave squealing a high-pitched
whine. And there was noise coming from the fridge motor. At that point,
I could see that there was about 60 volts on the line, enough so that
when I turned the lights on, they came on, sorta dimly.

After that, the line voltage fluctuated wildly, going from a low of
about 45 volts all the way above 80. My guess is that they (the power
co.) were switching things in and out, and that was causing the ups and
downs. Another unusual thing I noticed was that my neighbor's diesel
generator kicked in when the power went out (they have a small server
farm they like to keep alive). But every time the voltage went above 80
volts, the thing would turn itself off--which meant that they were
running on low voltage for at least part of the time.

I found out that my TV (old analog) and DTV converter work fine on about
75 volts. I didn't want to find out about my computah, so I turned it
off. Also turned off the fridge because I didn't like the sounds I heard
coming from the compressor.

--
Made From Pears: Pretty good chance that the product is at least
mostly pears.
Made With Pears: Pretty good chance that pears will be detectable in
the product.
Contains Pears: *One pear seed per multiple tons of product.

(with apologies to Dorothy L. Sayers)

When I lived in Ga there was a small substation, a subsub station if
you will behind the place I worked. This substation fed an industrial
park and quite a large residential area.When lightning hit one of the
transformers there it blew and so did one of the transformers that fed
where I worked, we had three for three phase power. Power was out in a
patchwork all over the residential area and 3 or four other
transformers also blew up scattered around the subdivision. On one
road in particular you could tell that every third street off the road
was without power.




Jimmie