Analysis of Current Density in Soil for Resistivity Measurements and Electrical Grounding Designs
Journal of Electrical and Electronic Engineering
Volume 5, Issue 5, October 2017, Pages: 198-208
Received: Dec. 5, 2017;
Published: Dec. 6, 2017
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Jie Liu, Department of Research and Development, Safe Engineering Services & Technologies ltd., Laval, Canada
Farid Paul Dawalibi, Department of Research and Development, Safe Engineering Services & Technologies ltd., Laval, Canada
Sharon Tee, Department of Research and Development, Safe Engineering Services & Technologies ltd., Laval, Canada
The design of electrical grounding systems is crucial to ensure people's safety and equipment integrity. The performance of the grounding system is critically dependent on the characteristics of the local soil surrounding the grounding system. Some wrong concepts and assumptions on soil electrical properties are still prevalent among professionals regarding soil resistivity measurements and grounding designs. The objective of this paper is to examine the current density in the earth surrounding measurement electrodes and electrical grounding systems and discuss the effects of soil structures on measurements and grounding related studies. The analyses described here are based on electromagnetic field theory. First, this paper examines soil resistivity measurements using the Wenner method in three typical, but different soil structure models, by exploring the distribution of earth current density in the soil surrounding the current injection electrodes. The computed results are illustrated using appropriate plots to understand better the influence of soil structure and characteristics on the current penetration across the soil layers. Furthermore, a detailed study on the influence of nearby buried grounding systems on soil resistivity measurements was also carried out. Finally, the performance of grounding systems in the three soil structure models has been studied in order to gain an intuitive understanding of the effects of soil structures on grounding. The results clarify and invalidate some misleading arguments used by a few practicians. All computed results are summarized in appropriate tables and figures which should provide helpful visual clues and useful information when planning soil resistivity measurements and designing electrical grounding systems.
Farid Paul Dawalibi,
Analysis of Current Density in Soil for Resistivity Measurements and Electrical Grounding Designs, Journal of Electrical and Electronic Engineering.
Vol. 5, No. 5,
2017, pp. 198-208.
F. P. Dawalibi and D. Mukhedkar, "Parametric Analysis of Grounding Grids," IEEE Transactions on PAS Vol. 98, No. 5, Sept.-Oct. 1979, pp. 1659-1668.
F. P. Dawalibi, D. Mukhedkar and D. Bensted, "Measured and Computed Current Densities in Buried Ground Conductors," IEEE PES 1981 Winter Meeting, Paper # 81 WM 128-8 PWRD.
F. P. Dawalibi and N. Barbeito, "Measurements and Computations of the Performance of Grounding Systems Buried in Multilayer Soils," IEEE Transactions on PWRD, Vol. 6, No. 4, October 1991, pp. 1483-1490.
F. P. Dawalibi, J. Ma, and R. D. Southey, "Behaviour of Grounding Systems in Multilayer Soils: a Parametric Analysis," IEEE Transactions on Power Delivery, Vol. 9, No. 1, January 1994, pp. 334-342.
H. Lee et al., “Efficient Grounding Designs in Layered Soils,” IEEE Trans. Power Del., vol. 13, No. 3, pp. 745–751, Jul. 1998.
J. Ma and F. P. Dawalibi, "Study of Influence of buried Metallic Structures on Soil Resistivity Measurements," IEEE Transactions on Power Delivery, Vol. 13, No. 2, April 1998, pp. 356-363.
R. D. Southey and F. P. Dawalibi, “Improving the Reliability of Power Systems with More Accurate Grounding System Resistance Estimates,” in Proc. Int. Conf. Power Syst. Technol., Oct. 2002, vol. 1, pp. 98–105.
H. Zhao, S. Fortin and F. P. Dawalibi, “Analysis of Grounding Systems Including Freely Oriented Plates of Arbitrary Shape in Multilayer Soils,” IEEE Transactions on Industry Applications, Vol. 51, No. 6, November/December 2015, pp. 5189-5197.
S. Fortin, N. Mitskevitch and F. P. Dawalibi, “Analysis of Grounding Systems in Horizontal Multilayer Soils Containing Finite Heterogeneities,” IEEE Transactions on Industry Applications, Vol. 51, No. 6, November/December 2015, pp. 5095-5100.
J. Liu, F. P. Dawalibi and B. F. Majerowicz, “Gas Insulated Substation Grounding System Design Using the Electromagnetic Field Method,” The 5th China International Conference on Electricity Distribution (CICED), Shanghai China, September 5-6, 2012.
X. Wu, V. Simha, and R. J. Wellman, “Strategies for designing a large EHV station ground grid with drastically different soil structures,” Transmission and Distribution Conference and Exposition (T&D), 2016 IEEE/PES. Dallas, TX, USA, 3-5 May 2016.
A. Ackerman, P. K. Sen, and C. Oertli, “Designing Safe and Reliable Grounding in AC Substations with Poor Soil Resistivity: An Interpretation of IEEE Std. 80,” IEEE Transactions on Industry Applications, Vol. 49, Issue. 4, July-Aug. 2013, pp. 1883-1889.
M. Nassereddine, J. Rizk, M. Nagrial, and A. Hellany, “Substation and Transmission Lines Earthing System Design under Substation Fault,” Electric Power Components and Systems, Volume 43, 2015 - Issue 18, September 2015, pp. 2010-2018.
F. P. Dawalibi and F. Donoso, "Integrated Analysis Software for Grounding, EMF, and EMI," IEEE Computer Applications in Power, Vol. 6, No. 2, April 1993, pp. 19-24.
R. S. Baishiki, C. K. Osterberg, and F. P. Dawalibi, "Earth Resistivity Measurements Using Cylindrical Electrodes at Short Spacings," IEEE Transactions on Power Delivery, Vol. 2, No. 1, January 1987, pp. 64-71.
A. Selby and F. P. Dawalibi, "Determination of Current Distribution in Energized Conductors for the Computation of Electromagnetic Fields," IEEE Transactions on Power Delivery, Vol. 9, No. 2, April 1994, pp. 1069-1078.