Re: An Electrolytic ground plane

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>

Hi,

At 02:43 PM 7/11/2004, you wrote:
>Tesla list wrote:
> >
> > Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>
> >
> > Hi John,
> >
> > Just like in high voltage transmission lines, the voltage is very high but
> > the current is low.  Thus, a bunch of resistance in your ground plane is
>
><snip>
>
>Cheers,
>
>          Terry
>
>Terry,
>
>Let's see, the ampacity of a typical 138 KV transmission line is 880
>amps.
>
>Typical 345 KV = 2640 amps
>
>Typical 765 KV = 3890 amps
>
>This is low current!?


"Relatively speaking" yes!  The source impedance of the above are 156, 131, 
and 197 ohms.  In the last case, the power is 3 gigawatts.  So we have 
three gigawatts with almost 200 ohms of source resistance ;-))   If that 
were at say 120VAC the current would be 25 megamps and the resistance would 
be 0.000005 ohms.  So by pumping the voltage sky high, we reduce the 
sensitivity to resistance by a factor of 40 million!!!

Now for a streamer, where the voltage is say 500000 volts and the current 
is 10 amps, we get 50000 ohms.  So 20 extra ohms in the ground plane just 
is not a factor to worry about.  However, if you power arc to ground (much 
higher currents) , then the path should be sort of conductive like a 
metal.  But don't worry about it being foil instead of solid silver ;-)))

Cheers,

         Terry



>Ed Wingate RATCB