without using a commercial program iam planning to develop a FORTRAN program to plot the GPR around the grid, please suggest some IEEE paper relevant to develop the flowchart and program
I hope to be fine. You can take a help from my paper under the title"Control the Cost, Touch and Step Voltages of the Grounding Grids Design". it contains a description for calculating earth surface potential for a grounding grids.
I recommend you to consult the document in attached file "IEEE standard for measurement of impedance and safety characteristics of Large extended of interconnection grounding system".