[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: steam power



Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-uswest-dot-net>" <jimlux-at-earthlink-dot-net>




> Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<evp-at-pacbell-dot-net>
>
> > >>*It's a safety issue and people are using this technique with
coils... -
> > Terry<<
>
> Don't know about the fire fighters, who have enough safety problems
> without worrying about electrocution, but Southern California Edison
> (and presumably all other utilities) routinely wash off the insulators
> on HV transmission lines; I've often seen it done and have been told
> (electric power transmission class in grad school) it's done with the
> line hot.  Nozzle and nozzle holder are on top of a cherry picker
> mounted on a truck. and brought up to perhaps from the insulators.  In
> at least once case the insulators being washed were on the 220 kV HV
> line which, as far as I know, was the only source of power for the area
> I was in, which would tend to verify that the lines were not disabled.
> Someone here must have better knowledge as to what is really done.

An interesting device called an "interrupter" which pulses the water stream.
As long as the stream is not continuous, there's no problem.  Occasionally,
the interrupter fails, and spectacular(!) results ensue.

Even at 200 kV, the sparkover distance is on the order of 3 or 4 inches, say
a foot in a nonuniform field.  As long as the cumulative air gap between the
droplets is an order of magnitude greater, there isn't any problem.  A 50
foot stream of water (with gaps and droplets) is likely to have at least
that much gap.

A TC is sort of a different can of worms, because a) the voltage is much
higher (on the order of 500 kV to 1 MV) and b) the field is already pretty
nonuniform.