Images of rods in two layer soil

[strongone]

i am having a little difficulty tracking images in two layer soil, when the field point is above the earths surface and the source segment is either in the top or lower layer of the two layer soil model.

i am trying to calcuate the potential on the earth's surface due to a rod(horizontal or vertical) in the lower or upper layer of the soil. I know where the images are when the field segment is either in the upper or lower layer of the soil.

any kind of help will be greatly appreciated ziax@tstt.net.tt
its a simple problem

 

[jbartos]

Question: Which media do you use between the upper soil layer and a field point above the upper soil level? Do you use a software that would accept the third (soil) layer?

 

[strongone]

no i am not using any software, i just need to know the location of the images, when the field point is above the earth's surface. for exapmle if a horizontal rod is buried at a depth D, and the surface layer thickness is H. Where are the location of the images of the rod segment when it is in the bottom and top layer soil layers, wrt the field segment which is above the earth's surface.
[1] and [3] both give the locations of the images but the, seem to be contradictory, at least from my point of view

[1] Heppe R.J., 1979, Computation of potential at surface above an energized grid or other electrode, allowing for non-uniform current distribution", IEEE Trans. on Power App. and Sys., 98, 1978-88.

[2] Chow, Elsherbiny, Salama, "Surface voltages and resistance of grounding systems of grid and rods in two-layer earth by rapid Galerkin's moment method", IEEE Trans. on Power Delivery, Vol. 12, No. 1, January 1997, pages 179-185

 

[jbartos]

Comment: [1] gives a sample of Fortran programming of Rij for i=3,4 and j=3,4
Is programming of mathematical relationships being used or how results are obtained?
Appendix includes the statement:
"..if we derive a general formula for the voltage produced by line source, and always remember to apply it twice, once with the z coordinate of the source and once with the z coordinate of the image. ...."

 

[strongone]

i am quite familiar with the method in [1], i have even implemented it, not for two-layer though.

my problem is the theory , the appendix of [1] gives the location of the images when the field segment/point is in the soil. I understand that situation.

ok this is the question
Is the system of images the same whether or not the field segment/point lies in the soil or air???