[AMPS] HV Pole Pigs ++ (OT)
wb8jkr@juno.com
wb8jkr@juno.com
Thu, 20 Dec 2001 19:28:06 -0500
That's completely goofy. The neutral wire is
the support wire that the low side cables wrapped
around. The pole grounds are for lightening, not
60 Hz return. In the U.S. the top three wires are
each a phase of a three phase system, the common
is on the pole 48" down.
Mark WB8JKR
On Thu, 20 Dec 2001 19:07:28 -0500 Jerry Flanders <jflanders2@home.com>
writes:
>
> Talk of canadian pole pigs reminds me of something strange I saw in
> Canada
> a few years ago and verified again last summer: Some places in
> central
> Canada (I think it was MB or perhaps the contiguous province west of
> it)
> have soil conductivity so high that the local power company uses
> earth as
> the return conductor for AC power distribution!
>
> I was driving down the highway (probably hwy 16) there in 1998 and
> noticed
> only _one_ wire for a HV power distribution system (BIG insulators).
> I
> asked at the next stop about that weirdness and the guy I was
> talking with
> first assured me that it must have been telephone wire because power
>
> systems always use 2 or more llines, but it just so happened that
> his
> friend worked for the power company so he would just call to verify.
> Well,
> his friend confirmed that indeed it was their power distribution
> system,
> and they only needed one conductor because of the extremely high
> conductivity of the earth in that area.
>
> We drove through this same area last summer and they are still using
> only
> one conductor. I don't remember the exact area off-hand, but could
> locate
> it on the map if I had to.
>
> I can't help but wonder how efficient that system was.
>
> Jerry W4UK
>
> At 05:53 PM 12/20/2001 -0500, Phil (VA3UX) wrote:
>
> >Not a bad point Jack. Ultimately most of the pigs are removed from
> the
> >can when used for amateur service. I don't know about the standards
> in the
> >US but here in Canada, these pole transformers had to have enough
> sheet
> >insulation between winding layers to meet the electrical
> requirements
> >*before* they were put in oil. The oil then just added a huge
> additional
> >insulation factor as well as providing the required cooling. This
> came
> >from a conversation I had with a design engineer at
> Ferranti-Packard (at
> >one time, one of the largest makers of pole transformers in
> Canada). So at
> >least in Canada, these things can be safely run dry. However the
> sheet
> >insulation is still subject to the same time/temperature/aging
> effects as
> >any other transformer so eventual failure is expected.
> >
> >Phil
>
>
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