See:
Melipoulos, A.P.S.; Xia, F.; Joy, E.B.; Cokkinides, G.J.
"An advanced computer model for grounding system analysis"
IEEE Transactions on Power Delivery, Jan. 1993, Volume: 8 , Issue: 1, pp 13 - 23
Abstract
An advanced methodology and a computer model for analysis of practical grounding systems based on the method of moments are presented. The practical methodology is applicable to both simple and complex grounding systems. The grounding system may consist of cylindrical conductors as well as rectangular earth conductors or metallic surfaces buried in earth or located on the surface of the earth. The method consists of computing an equivalent circuit model of the earth embedded electrodes and conductive soil. Uniform or two-layer soil can he accommodated. The problem of computational efficiency is addressed. Several innovations have been introduced to minimize execution time, including adaptive segmentation of grounding structures and adaptive computation of self and mutual impedances. The procedure enables accurate computation of touch and step voltages, body currents, grounding system impedance, voltage profile, etc. The method and computer program have been validated with actual system measurements
F. P. Dawalibi and D. Mukhedkar,
"Optimum Design of Substation Grounding in Two-Layer Earth Structure - Part II, Comparison Between Theoretical and Experimental Results,"
IEEE Transactions on Power Apparatus and Systems,Vol.PAS-94, No. 2, March/April 1975, pp. 262-266.
Ma, J. and Dawalibi, F.P.
"Modern computational methods for the design and analysis of power system grounding"
1998 International Conference on Power System Technology, 1998. Proceedings. POWERCON '98,18-21 Aug. 1998, Volume: 1
pp 122 - 126
Abstract
This paper examines a few methods used in power system grounding analysis and illustrates the advantages, limitations and the applicability of these methods. Computation results using these methods are presented and compared the various cases modeled in this paper include grounding networks of different sizes, grounding networks with buried metallic structures, such as steel pipes, and high frequency cases. The discussions and conclusions given in this paper can be used as a reference when deciding which method should be used to carry out an accurate and efficient grounding analysis
