Science Journal of Circuits, Systems and Signal Processing

Submit a Manuscript

Publishing with us to make your research visible to the widest possible audience.

Propose a Special Issue

Building a community of authors and readers to discuss the latest research and develop new ideas.

Analysis of Design Parameters on Substation Earth Grid Safety Limits

In power systems, earthing is one of the most fundamental aspects that play a key role in ensuring the safety of personnel and equipment in a substation as well as reliable operation of the power system. Various elements within the earthing system scope play a vital role in ensuring compliance with relevant specifications, and these include design parameters such as soil resistivity, system fault level, conductor size, and the safety limits of touch voltage, step voltage, and the ground potential rise (GPR). In this paper, the influence of design parameters such as earth grid surface materials and asymmetrical fault currents on the design and performance of earthing systems are modeled, simulated, and analyzed. The Wenner four-pin method was used to conduct soil surveys and the collected data was used to design an earth grid according to the IEEE Std 80-2013 guidelines. The Electrical Transient Analyzer Program (ETAP) and MATLAB/Simulation engineering tools were used to model and analyze the design parameters. ETAP was used to assess the impact of different surface materials and MATLAB/Simulink was used to assess the influence of asymmetrical fault currents on the earth grid. From the analysis of the surface materials, it was observed that the crusher run granite is the most effective surface material for earth grids compared to the other surface materials studied. Furthermore, the impact of the surface material depth was studied using the crushed rocks, and results show that the depth of the surface material has an impact on the tolerable safety limits. Analyses were conducted in MATLAB/Simulink to assess the impact of asymmetrical faults (Line to Ground and Double Line to Ground) on touch voltage, step voltage, and ground potential rise. From the simulations, it was observed that the type of fault determines the magnitude of touch voltage, step voltage, and ground potential rise. From the analyses, it is concluded that the crusher run granite stones are the most effective surface material and should be used for earth grid designs, also, that the surface material should be buried as close to the surface as possible. Lastly, it is concluded that the type of system fault determines the magnitude of touch voltage, step voltage, and ground potential rise.

Substation Earth Grid, Touch Voltage, Step Voltage, Ground Potential Rise, ETAP, MATLAB/Simulink

APA Style

Vuyani Michael Nicholas Dladla, Agha Francis Nnachi, Rembuluwani Philip Tshubwana. (2022). Analysis of Design Parameters on Substation Earth Grid Safety Limits. Science Journal of Circuits, Systems and Signal Processing, 10(2), 61-72. https://doi.org/10.11648/j.cssp.20211002.14

ACS Style

Vuyani Michael Nicholas Dladla; Agha Francis Nnachi; Rembuluwani Philip Tshubwana. Analysis of Design Parameters on Substation Earth Grid Safety Limits. Sci. J. Circuits Syst. Signal Process. 2022, 10(2), 61-72. doi: 10.11648/j.cssp.20211002.14

AMA Style

Vuyani Michael Nicholas Dladla, Agha Francis Nnachi, Rembuluwani Philip Tshubwana. Analysis of Design Parameters on Substation Earth Grid Safety Limits. Sci J Circuits Syst Signal Process. 2022;10(2):61-72. doi: 10.11648/j.cssp.20211002.14

Copyright © 2021 Authors retain the copyright of this article.
This article is an open access article distributed under the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/) which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

1. B. Z. Nongena, A. F. Nnachi, R. P. Tshubwana, and C. G. Richards, “Substation Earth Grid modeling and simulation for Transient Performance Analysis,” IEEE 62nd International Midwest Symposium on Circuits and Systems (MWSCAS), 2019, pp. 517-520.
2. V. M. N. Dladla, A. F. Nnachi and R. P. Tshubwana, "Analysis of Varying Soil Resistivity on Substation Earthing Design and Performance Using ETAP," 2022 30th Southern African Universities Power Engineering Conference (SAUPEC), 2022, pp. 1-6.
3. V. M. N. Dladla, A. F. Nnachi and R. P. Tshubwana, "The Impact of Different Fault Types on Touch Voltage, Step Voltage, and Ground Potential Rise," 2022 30th Southern African Universities Power Engineering Conference (SAUPEC), 2022, pp. 1-6.
4. N. Jose, “Design of Earth Grid for a 33/11kV GIS Substation at a High Soil Resistivity Site using CYMGRD Software”, International Journal of Engineering Research & Technology (IJERT), Vol 3 (10) October 2014, pp. 1151-1155.
5. D. B. Desai, “Design and analysis of ground grid system for substation using E-TAP software and FDM code in MATLAB,” International Journal of Engineering Research & Technology (IJERT), Vol. 7 (10), October 2018, pp. 51-53.
6. D. Jacob, and K. Nithiyananthan, “Effective methods for lower systems grounding”. WSEAS Transactions on business and economics. Vol. 5 (5) May 2008, pp. 151-160.
7. V. P. Androvitsaneas, K. D. Damianaki, C. A. Christodoulou, and I. F. Gonos, I. F. “Effect of Soil Resistivity Measurement on the Safe Design of Grounding Systems”. Energies 2020, 13, 3170. 2020.
8. N. Permal, M. Osman, A. M. Ariffin, A. B. Abidin and M. Z. Kadir, “Effect of Non-Homogeneous Soil Characteristics on Substation Grounding-Grid Performances: A Review”. Appl. Sci. 2021, 11, 7468, 2020.
9. IEEE. “IEEE Std 80-2013: IEEE Guide for Safety in AC Substation Grounding,” The Institute of Electrical and Electronics Engineers, Inc. New York, January 2000A. Salam and Q. M. Rahman, “‘Soil Resistivity’, in Power Systems Grounding,” Singapore: Springer Science + Business Media Singapore. 2016.
10. IEEE, “IEEE Std 81-2012: IEEE Guide for Measuring Earth Resistivity, Ground Impedance, and Earth Surface Potentials of a Grounding System”. The Institute of Electrical and Electronics Engineers, Inc. New York, December 2012.
11. L. L, Win, K. T, Soe, “Design Consideration of Electrical Earthing System for High-rise Building,” American Scientific Research Journal for Engineering, Technology, and Sciences (ASRJETS). Vol 26 (2) 2016, pp. 270-282.
12. H. N. Amadi, “Soil Resistivity Investigations for Substation Grounding Systems In Wetland Regions – A Case Study Of Lagos State, Nigeria,” Asian Journal of Natural & Applied Sciences. Vol 6 (4), December 2017, pp. 94-95.
13. O. E. Gouda O. E, G. M. Amer and T. M. El-Saied, “Factors affecting the apparent soil resistivity of multi-layer Soil,” Proceedings of 14th International Symposium on High Voltage Engineering (ISH 2005), Beijing, China, August 25-29, 2005.
14. A. Salam and Q. M. Rahman, “‘Soil Resistivity’, in Power Systems Grounding,” Singapore: Springer Science + Business Media Singapore. 2016.
15. A. Patil, “Substation Earthing Design,” IOSR Journal of Electrical and Electronics Engineering (IOSR-JEEE), Vol. 12 (1) Ver. II, January 2017, pp. 12-17.
16. D. Sweeting, “Applying IEC 60909, Fault Current Calculations,” IEEE Trans. Industry App., vol. 48, no. 2, March/April 2012., pp. 575-580.
17. K. S. Ratnadeep, Y. N. Bhosale, S. Kulkarni, “Fault Level Analysis of Power Distribution System,” 2013 International Conference on Energy Efficient Technologies for Sustainability – Nagercoil. April 2013.
18. A. Salam and Q. M. Rahman, “‘Ground Resistance Measurement’, in Power Systems Grounding,” Singapore: Springer Science + Business Media Singapore. 2016.
19. Fluke Corporation, “Earth Grounding Resistance – Principles, Testing Methods and Applications,” Everett: Fluke Corporation, 2013, pp 3-5.
20. V. M. N. Dladla, A. F. Nnachi and R. P. Tshubwana, "The Impact of System Fault Level on the Design of a Substation Earthing Grid Simulation Using ETAP," 2022 30th Southern African Universities Power Engineering Conference (SAUPEC), 2022, pp. 1-6.
21. A. G. Swanson, M. Brown, K. Moodley and A. Singh, "Resistivity of Surface Materials for Substation Earthing," 2020 IEEE PES/IAS Power Africa, 2020, pp. 1-5.