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PIG failure modes



Original poster: "Gerry  Reynolds" <gerrytesla@xxxxxxx>

Hi Dr R.

I'm trying to get a feel for PIG failure modes and I'm guessing that the one you are refering to below is overvoltage due to length dependent resonances that can result when shielded coax is used to route power from the PIG to the TC and the system is underdamped. DO you or ANYONE else know if a PIG will be damaged by voltages less than the BIL rating. I have a 5KVA pig that has the following ratings (but no BIL rating):

LV: 120/240
HV: 14400/24940

Im presuming the 24940V refers to an application where the pig is connected across two phases of a Y three phase distribution system where each leg of the Y is 14400V and sees 24940 volts across its HV bushings. If this is true, this would suggest to me that operating the pig in a TC SRSG system at 25000V would be no problem for the pig (assuming the temp rise spec of 65 degrees C is honored and the KVA rating isn't violated too excessively). If someone could elaborate more on PIG failure modes, I would be grateful.

Gerry R

BTW: I got a new email address dedicated to this tesla group (gerrytesla@xxxxxxx)

Original poster: "Dr. Resonance" <resonance@xxxxxxxxxx>


Don't do this --- you could blow your pig with a cap at the other end!!!

Dr. Resonance

>
>  > Original poster: Esondrmn@xxxxxxx
>  >
>  > Drew,
>  >
>  > Not sure about the HV cables hissing.  Do you have them laying on
>  > the
>  > cement?  What kind of wire are you using?  How close together are
>  > they?  I
>  > use RG213 with the outer jacket and ground sheath removed and the
>  > cables
>  > are sitting on 2 x 4s on the cement.
>
> Not sure that this is recomended but I use x-ray HV cables
> with the grounding sheaths intact and gronded at the mains
> ground at the pole transformer. They certainly don't hiss
> in this setup although this may be a NO-NO from an RF kick
> back stand-point?? I've heard that this type of setup also
> causes a "Blumline effect" which causes voltage levels to
> reach much higher than the output voltage of the transformer
> itself, but I have not had any pole pig transformers to even
> hiccup from running like this. One reason I do it this way
> is to stop the hissing and to make it safer if the lines are
> touched while energized. I know the electrical utility com-
> panies must use this method on all of their underground power
> lines. Any observation/comments from others on this matter
> are welcome....
>
>
> David Rieben
>
>
>