volume | PIER Journals

Abstract

The paper presents a method of determination of ground fault current distribution when HV (high voltage) substations are located in urban or suburban areas, or where many relevant data necessary for determination of this distribution are uncertain or completely unknown. The problem appears as a consequence of the fact that many of urban metal installations are situated under the surface of the ground and cannot be visually determined or verified. On the basis of on-the-site measurements, the developed method enables compensating all deficiencies of the relevant data about metal installations involved with the fluctuating magnet field appearing around and along a feeding power line during an unbalanced fault. The presented analytical procedure is based on the fact that two measurable quantities, currents in one phase conductor and in one neutral line conductor, cumulatively involve the inductive effects of all, known and unknown surrounding metal installations. Once, this quantity has been determined, the problem of determination of different parts of a ground fault current becomes solvable by using a relatively simple calculation procedure. The presented quantitative analysis indicates at the benefits that can be obtained by taking into account the presence of surrounding metal installations.

1. "IEEE guide for safety in AC substation groundin,", IEEE Std. 80, 2000.
doi:10.1002/j.1538-7305.1926.tb00122.x Google Scholar

2. "Short-circuits currents in three-phase A.C. system --- Part 3: Currents during two separate simultaneous line-to-earth short circuit and partial short-circuit °owing trough earth,", IEC Int. Std. 60909-3, Ed. II, 2003. Google Scholar

3. Carson, J. R., "Wave propagation in overhead wires with ground return," Bell Syst. Tech. J., Vol. 5, No. 4, 539-554, 1926. Google Scholar

4. Pollaczek, F., "Ueber das Feld einer unendlich langen wechselstrom-durchflossenen Einfachleitung," Electrische Nachrichtentechnik, Vol. 3, No. 4, 339-359, 1926.
doi:10.1109/TPAS.1984.318744 Google Scholar

5. Endreny, J., "Analysis of transmission tower potentials during ground faults," IEEE Trans. Power App. Syst., Vol. 86, No. 10, 1274-1283, Oct. 1967.
doi:10.1109/61.660868 Google Scholar

6. Dawalibi, F. and G. Niles, "Measurements and computations of fault current distribution on overhead transmission lines," IEEE Trans. Power App. Syst., Vol. 103, No. 3, 553-560, Mar. 1984.
doi:10.1109/61.193956 Google Scholar

7. Lj, M. P., "Practical method for evaluating ground fault current distribution in station, towers and ground wire," IEEE Transactions on Power Delivery, Vol. 13, No. 1, 123-129, Jan. 1998.
doi:10.1109/TPWRD.2007.915895 Google Scholar

8. Sobral, S. T., J. O. Barbosa, and V. S. Costa, "Grounding potential rise characteristics of urban step-down substations fed by power cables --- A practical example," IEEE Trans. Power Del., Vol. 3, No. 2, 1564-1572, Apr. 1988. Google Scholar

9. Mangione, S., "A simple method for evaluating ground-fault current transfer at the transient station of a combined overhead cable line," IEEE Trans. Power Del., Vol. 23, No. 3, 1413-1418, Jul. 2008.
doi:10.1109/61.852984 Google Scholar

10. Waes, J., M. Riet, F. Proroost, and . Goben, "Measurements of the current distribution neara substation during a single phase to ground fault," Proc. CIRED 17th Int. Conf. on Electrical Distribution, Barcelona, Spain, May 2003. Google Scholar

11. Lj, M. P., "Efficient reduction of fault current through the grounding grid of substation supplied by cable line," IEEE Trans. Power Del., Vol. 15, No. 2, 556-561, Apr. 2000.
doi:10.1002/etep.172 Google Scholar

12. Campuccia, A. and G. Zizzo, "A study of the use bare buried conductors in an extended interconnected earthing systems inside a MV network," 18th International Conference on Electricity Distribution, 1-5, CIRED, Turin, Jun. 6-9, 2005. Google Scholar

13. Lj, M. P., "Improved analytical expressions for the determination of the reduction factor of the feeding line consisting of tree single-core cables," European Transactions on Electrical Power, Vol. 18, 190-203, 2008.
doi:10.1049/iet-gtd.2009.0665 Google Scholar

14. Lj, M. P., "In°uence of the metal installations surrounding the feeding cable line on the ground fault current distribution in supplied substations," IEEE Trans. Power Del., Vol. 23, No. 4, 2583-2590, Oct. 2008. Google Scholar

15. Lj, M. P., "Testing and evaluating grounding systems for substations located in urban areas," IET Gener. Trans. and Distr., Vol. 5, No. 2, 231-238, Feb. 2011. Google Scholar

16. Lj, M. P., "Transfer characteristics of electric-power lines passing through urban and suburban areas," International journal of Electrical Power & Energy Systems, Vol. 56, 151-158, Mar. 2014.
doi:10.1109/TPWRD.2005.848737 Google Scholar

17. "Guide concerning in°uence of HV AC power systems on metallic pipelines,", CIGRE Working Group 36.02, Canada, 1995.
doi:10.1109/TPWRD.2006.881465 Google Scholar

18. Tsiamitros, D. A., G. K. Papagiannis, D. P. Labridis, and P. S. Dokopoulos, "Earth return path impedances of underground cables for the two-layers earth case," IEEE Trans. Power Del., Vol. 20, No. 3, 2174-2181, Jul. 2005.
doi:10.1016/j.epsr.2010.10.001 Google Scholar

19. Tsiamitros, D. A., G. K. Papagiannis, and P. S. Dokopoulos, "Homogenous earth approximation of two-layer earth structures: An Equivalent resistivity approach," IEEE Trans. Power Del., Vol. 22, No. 1, 658-666, Jan. 2007. Google Scholar

20. Lj, M. P., "Comparative analysis of grounding systems formed by MV cable lines with either uninsulated or insulated metal sheath(s)," Electric Power System Research, Vol. 81, No. 2, 393-399, Feb. 2011. Google Scholar

Dr. Ljubivoje M. Popovic