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RE: power line insulators



On Fri, 13 Jun 1997, Brad Shue wrote:
Question: Someone stated that high voltage passed through water more
easily. I'm not familiar with this. I have always been told that the
conductivity depended on the purity of the water, regardless of the
voltage applied. Remember that this is AC, not DC from a Van de Graff
generator. Remember, water does have an impedance when AC is applied
instead of being polarized by a DC voltage. Any thoughts?

Actually I was just talking about Ohm's law; that for higher voltages, any
given resistance SEEMS smaller. To a 1.5v flashlight battery, 1000 ohms
of water is "insulating", and only draws a couple of milliwatts. The same
1000 ohms if placed across a typical 17,000 power line will eat up 300,000
watts! As in: BANG! My suspicion is that rainstorms cause buzzing and
steaming of insulators, but that any wet pathway is instantly vaporized,
so the average leakage current is low.

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