baltoche

Thanks to Enthalpy for his reply, I do appreciate. For easiness reasons, I consider that my sol is uniform. I've issued and attached a document inn which I tried to clarify my concerns? All your contributions will be welcome. Kind ReSciences forum.pdfgards.

Gents, Thanks for your contributions. @Daniel : you're right, instead of voltage, I meant the resistance... @Studiot : you're also right, the hemisphere correspond to an earth resistance located at the surface of the ground. Having said that, suppose two points both buried in the ground and separated by a distance d. Is it posible to define the resistance between them if the medium in which they are buried is homogeneous and has got a resistivity Rho ? Thanks and good evening To Studiot... I went to the websites you kindly provided me with. Near the firsty one you quoted, I found an intersting site : http://gpg.geosci.xyz/en/latest/content/electromagnetics/principles_of_em_induction.html If you go to this site, you canfind an interesting sketch : http://gpg.geosci.xyz/en/latest/_images/Tx_Rx_schematic.jpg where part of the signal sent to a transmitter to a receiver flows in the ground instead of using a nominal path at the surface of the ground. This is exactly what I'm trying to do in dc ! I have several dc potentials (with respect to far earth) distributed at the top surface of the soil. Such potentials behave as current sources. For each of these dc currents sources, part of the current uses a nominal path to reach othe potentials on the surface, but another part uses the ground, including the far earth as a "secondary path". My goal is to modelise the soil between each of these ppoints as well as the far earth. Maybe I can try to draw something for you. Meanwhile, thanks again for your support. Good night !

Dear All, First, please apologise my bad English (I'm not from the UK...). If my wording is not clear enough, please don't hesitate to ask me. I'm interested in dc current distribution into the ground for modelling purposes. I could read on a technical paper that the voltage between two points in a homogeneous ground (constant resistivity) could be calculated by V=Rho/(2xPixd) where: - Rho is the ground resistivity (in Ohm.m) - V is the voltage between the two considered points (in V) - d is the distance separating the two points. The formula is extracted from the resistance of half a sphere and whose center is point A, whilst point B is on the surface of the half-sphere, the redus of such a sphere being d. First there is a doubt on whether to consider half a sphere or a full sphere, but beyond the model itself, I, I find the formula to much simple... What do you think ? Thanks and Regards.