Open Access Open Access  Restricted Access Subscription or Fee Access

Analysis of the Design Calculations for Electrical Earthing Systems


(*) Corresponding author


Authors' affiliations


DOI: https://doi.org/10.15866/iree.v16i2.16839

Abstract


Earthing systems play an essential role in electrical systems in terms of safety for people in the vicinity against the hazard of electric shocks as well as protection and proper operation of equipment during the incidence of faults. Both are achieved by providing a low-impedance path that can dissipate fault currents to the conductive mass of Earth. One of the first steps in the design of an earthing system is estimating the total resistance to earth and determining the proper size and basic layout of the earth electrode required. Engineers must design adequate earthing systems that comply with international standards and national regulations, which in fact incorporate a variety of earthing methods and various formulae to obtain the design parameters, especially the earthing resistance. The effects of using the varied formulae for each earthing technique are ambiguous and entail considerable risks, and thus require comprehensive compilations and critical examinations. This paper reviews many of the earthing design formulae available in widely used international standards and published scientific papers for a comparative analysis of their differences. The results of a rigorous survey for each earthing type, based on respective electrical resistances’ calculations evaluated for a specified range of resistivities, are presented in line graphs to show precise trends. A recommended list of the most conservative formulae from a safety perspective, based on the results obtained, is outlined as a basis for computing the earthing resistance for designing effective earthing systems. This provides a beneficial compact reference to facilitate the revision and provision of international earthing standards agreement.
Copyright © 2021 The Authors - Published by Praise Worthy Prize under the CC BY-NC-ND license.

Keywords


Earthing System; Electrical Safety Standards; Resistance Calculations; Soil Resistivity

Full Text:

PDF


References


Institute of Electrical and Electronics Engineers, IEEE Std-142 (Green Book): IEEE Recommended Practice for Grounding of Industrial and Commercial Power Systems (New York: IEEE, 2007).
https://doi.org/10.1109/ieeestd.1982.119223

British Standards Institution, BS7430: Code of practice for protective earthing of electrical installations (Milton Keynes: BSI, 2011).

B. Scaddan, Electrical Installation Work (Woburn:Newnes, 2002).

Schneider Electric, Available Online. Retrieved on 27th July 2018 from: http://theguide.schneider-electric.com

Institute of Electrical and Electronics Engineers. IEEE 80: 2000. Guide for Safety in AC Substation Grounding (New York: IEEE, 2000).

Lim, S.C., Gomes, C. and Ab Kadir, M.Z.A., Electrical earthing in troubled environment, International Journal of Electrical Power & Energy Systems, May 2013: 47(1), pp. 117 – 128, ISSN 0142-015.
https://doi.org/10.1016/j.ijepes.2012.10.058

Lim, S.C., Choun, L.W., Gomes, C. and Kadir, M.Z.A.A., Environmental effects on the performance of electrical grounding systems, IEEE International Power Engineering and Optimisation Conference, June 2013, pp. 330 – 333.
https://doi.org/10.1109/peoco.2013.6564567

Lim, S.C., Gomes, C. and Ab Kadir, M.Z.A. Significance of localized soil resistivity in designing a grounding system. IEEE International Power Engineering and Optimisation Conference, March 2014, pp. 324 – 329.
https://doi.org/10.1109/peoco.2014.6814448

Nahman, J and Svenda, G., Power and earthing system modelling in natural coordinates, International Journal of Electrical Power & Energy Systems, August 2001:24 (7): 541 – 549, ISSN 0142-0615.
https://doi.org/10.1016/s0142-0615(01)00062-x

Laurent, P., The general bases of the technique of earthing in electrical installations. The bulletin of the French Society of Electricians, 1967 (Translated from the original French in IEEE guide for safety in AC substation grounding, IEEE-Standard-80, (ANSI/IEEE, 1986).

Niemann, J., Conversion of high-voltage earthing systems to operation with a rigidly earthed stem point. Electrotechnische Zeitschrift. May 1952, pp. 333 – 337.

Tagg,G.F., Earth Resistance (England: George Newnes ltd, 1964).

Sunde, E.D., Earth conduction effects in transmission line systems (Dover Publications Inc., 1968).

Energy Network Association, ENA ER/S.34. A guide for assessing the rise of earth potential at substation site, 1986.

Sullivan, J.A., Alternative earthing calculations for grids and rods, IEEE Proc. Gener. Transm. Distrib, May 1998.
https://doi.org/10.1049/ip-gtd:19981696

Gomez, J., Design and Calculation of an earth electrode (CERN-ST-2000-053, February 2000).

Dwight, H.B., Calculation of resistance to ground, Electrical Engineering, December 1936, pp. 1319 – 1328.

Rudenberg, R., Basic Considerations Concerning Systems. Electrotechnische Zeitschrift. 1926: (11&12) (Translated from the original German in IEEE guide for safety in AC substation grounding, (ANSI/IEEE Standard-80,1986).

Liew, A.C. and Darveniza, M., Dynamic model of impulse characteristics of concentrated earth. Pmc. IEE, February 1974.

Zhang, X., A simplified method for calculating the impulse resistance of vertical grounding rods, Proceedings of IEEE TENCON, October 2002, pp: 1881 – 1884. ISBN: 0-7803-7490-8.

Shukri, A., Arief, Z., and Sidik, M., A systematic approach to safe and effective earthing system design for high voltage substation, Applied Mechanics and Materials, Trans Tech Publications, January 2016, pp. 146 – 150.
https://doi.org/10.4028/www.scientific.net/amm.818.146

Heppe, R.J., Step potentials and body currents near grounds in two-layer earth, IEEE Transaction on Power Apparatus and System Voltages, January/February 1979, pp. 45 – 59.
https://doi.org/10.1109/tpas.1979.319512

Yasuda, Y., and Fujii, T., Equivalent equation of earth resistance for ring electrode of wind turbine, 30th International Conference on Lightning Protection – ICLP, September 2010, Cagliari, Italy, pp. 1 – 4.
https://doi.org/10.1109/iclp.2010.7845823

Schwarz, S. J., S34 - A guide for assessing the rise of earth potential at substation sites Electricity Council Engineering Recommendation, Analytical expressions for the resistance of grounding systems, AIEE Transaction, 1954.

Energy Networks Association, Technical Specification 41-24-1992 EA (Engineering and safety publications: 1992).

Güemes-Alonso, J.A., Hernando-Fernández, F.E., Rodríguez-Bona, F. and Ruiz-Moll, J.M., A practical approach for determining the ground resistance of grounding grids, IEEE Transactions on Power Delivery, July 2006, pp. 1261 – 1266.
https://doi.org/10.1109/tpwrd.2006.874121

Sverak, J.G., Optimised grounding grid design using variable spacing technique, IEEE Transactions on Power Apparatus and Systems, January/February 1976, PAS-95(1): pp. 362 – 374.
https://doi.org/10.1109/t-pas.1976.32113

Schwarz, S.J., Analytical expressions for the resistance of grounding system. (Translated from the original French in IEEE guide for safety in AC substation grounding, IEEE-Standard-80 (ANSI/IEEE,1986). July 1951, pp. 368 – 402.
https://doi.org/10.1109/ieeestd.1986.81070

Kercel, S.W., Design of switchyard grounding systems using multiple grids, IEEE Transactions on Power Apparatus and Systems, March 1981, PAS-100(3): 3411350.
https://doi.org/10.1109/tpas.1981.316607

Wiener, P., A comparison of concrete-encased grounding electrodes to driven ground rods, IEEE Trans. Industry and General Applications, May/June 1970: IGA-6: 282287.
https://doi.org/10.1109/tiga.1970.4181179

Fagan, E.J. and Lee, R.H., The use of concrete-enclosed reinforcing rods as grounding electrodes, IEEE Transactions on Industry and General Applications, July/August 1970. IGA-6(4).
https://doi.org/10.1109/tiga.1970.4181193

Lim, S.C., Gomes, C. and Ab. Kadir, M.Z.A., Behaviour of a new material that improves ufer grounding practice, Journal of Electrical Systems, May 2016: 12(2): pp. 291 – 300.

Lim, S.C., Gomes, C., Aziz, N. and Ab. Kadir, M.Z.A., Steady state performance of improvised ufer grounding practice, International Conference on Lightning Protection, December 2014, pp. 572 – 580.
https://doi.org/10.1109/iclp.2014.6973190

Lim, S.C., Gomes, C., Buba, S.D. and Ab. Kadir, M.Z.A., Preliminary results of the performance of grounding electrodes encased in bentonite-mixed concrete, International Conference on Lightning Protection, November 2012, pp. 572 – 580.
https://doi.org/10.1109/iclp.2012.6344296

Lim, S.C., Al-Shawesh, Y., A Systematic Method for the Design of Earthing System for Low-voltage Installations, Journal of Recent Technology and Engineering (IJRTE), vol.8, October 2019, pp. 12 – 15. ISSN: 2277-3878.
https://doi.org/10.35940/ijrte.c1003.1083s19

Yousef Al-Shawesh, Earthing System Design Tool for Low-voltage Installations, Electrical Engineering Portal, April 2020. Available Online:
https://electrical-engineering-portal.com/download-center/electrical-ms-excel-spreadsheets/design-earthing-system


Refbacks




Please send any question about this web site to info@praiseworthyprize.com
Copyright © 2005-2024 Praise Worthy Prize