> wrote in message
oups.com...
> I am PhD student and I doing some work on grounding resistance and I
> would like to develop a formula for CALCULATION OF EARTH RESISTANCE IN
> MULTI-LAYER EARTH STRUCTURE. and compare it with some field
> measuremnts...What do you think? Is it possible to develop such this
> formula?
> Just want to remind you again that my case of study (calculation of
> Earth resistance for the driven rod in a horizontally stratified
> multi-layer earth at non-homogeneous earth).
> If any body have any papers to help or any advice please do
> I would like to thank you in advance
> your Ram
I don't know if you could develop a formula like that. There are way too
many variables depending on the make-up of the strata <ae?>, etc... Do
remember, though, I'm no mathematician, but I am an electrician and know a
substantial amount about grounding.
That said, you could probably put something together for each kind of soil
(clay, caliche, rock, etc..) that you would be penetrating, get the answer
for each type, then plug all those answers into yet another formula to
arrive at some kind of average resistance. Actually, though, it would be
mostly moot because the current would seek the least resistive of all the
strats and dissipate (through your driven electrode) into that one without
even hardly looking at the other layers. Sure, there would be some amount of
drain into the more resistive strata, but it would be small compared to the
drain by the least resistive ones.
Take the case of a lightning strike in sand. Silica is an excellent
insulator, and when lightning strikes in the sand, it only fuses a small
"tubule" of glass as it seeks a solid ground source (i.e. the bulk of the
current doesn't dissipate into that strata, but punches on through to find a
less resistive one).
Folks, Pszemol wonders what this topic has to do with reefs, but I'll tell
ya'...everyone of us should know about, at the very least, the BASICS of
grounding. When I see someone putting together a MH system, and they have to
ask "where do I connect the green wire at the bulb?", I shudder.
We should also take the time to learn a little about surge protection,
because we all use computers to communicate with other reefers. And I'd bet
at least 20% (possibly many, many more) of the people who read this post
have something in their house plugged into one. I don't mean the plugstrip
"surge protectors", those don't do squat for a real surge. Rather, I mean
true surge suppression where excess voltage is shunted to earth.
Anyway, I'm rambling now....
Ram, If I were in your shoes, I'd have a look at grounding installations for
Cell Towers, TV stations, radio stations, and the like. There is EXTENSIVE
work already done on just the subject you seek. No need to reinvent the
wheel, at least not from scratch.
HTH and sorry to ramble,
Kev