A New Measurement Method of the Ground Resistance Using a Low-pass Filter in Energized Substations

지역필터를 이용한 수변전실 접지저항의 새로운 측정방법

  • Published : 2001.08.01

Abstract

This paper describes an advanced measuring method and precise evaluation of the ground resistance for the grounding system of energized substations and power equipments. A grounding system of substations consists of all interconnected grounding connections of grounded conductors, neutral ground wires, underground conductors of distribution lines, cable shields, grounding terminals of equipments, and etc. It is very difficult to measure the accurate ground resistance of the grounding terminals of equipments, and etc. It is very difficult to measure the accurate ground resistance of the grounding system of high voltage energized substations because of harmonic components caused by switched power supplies or overloads. The conventional fall-of-potential method may be subject to big error if stray ground currents and potentials are present. In this work, to improve the precision in measurements of the ground resistance by eliminating the effects of harmonic components and stray currents and potentials, the investigations of the ground resistance measurement by using a low pass filter in a model energized grounding system were conducted. The accuracy of ground resistance mesurements was evaluated as a function of the ratio of the test signal to noise (S/N). The errors due to the proposed ground resistance measurement method were decreased with increasing S/N and were less than 5[%] as S/N is 10. The proposed ground resistance measurement method appears to be considerably more accurate than the conventional fall-of -potential method. It is allows cancellation of the parasitic resistance of energized grounding systems, to employ the measurement method that allows cancellation of the parasitic effects due to other circulating ground currents and ground potential rises in practical situations.

Keywords

References

  1. 이복희, 이승칠, 접지의 핵심 기초 기술, 도서출판 義?, p.40, pp.64-69, 1999
  2. R. J. Gustafson, R. Pursley and V. D. Albertson, 'Seasonal Grounding Resistance Variations on Distribution Systems', IEEE Trans., Vol. PD-5, No. 2, pp.1013-1018, April 1990 https://doi.org/10.1109/61.53115
  3. V. Amoruso, M. Savino and M. Sylos Labini, 'Analysis of Large Grounding Systems for Earth-resistance Measurements in Two-layer soils', IEE Proceedings, Vol. 136, No. 3, pp.182-194, May 1989
  4. L. Maotang and L. Jing, 'A New Type of Grounding Resistance Measurement Method', IEEE Trans., Vol. IM-48, No. 5, pp.899-902, Oct. 1999 https://doi.org/10.1109/19.799643
  5. J. Ma and F. P. Dawalibi, 'Effects of Inductive Coupling between Leads in Ground Impedance Measurements using the Fall-of-potential Method', 1999 IEEE Transmission and Distribution Conference, Vol. 1, pp.266-271, 1999 https://doi.org/10.1109/TDC.1999.755359
  6. P. R. Pillai and E. P. Dick, 'A review on Testing and Evaluating Substation Grounding Systems', IEEE Trans., Vol.PD-7, No. 1, pp.53-61, Jan. 1992 https://doi.org/10.1109/61.108889
  7. H. R. Seedher, J. K. Arora and S. K. Soni, 'A Practical Approach for Computation of Grid Current', IEEE Trans., Vol. PD-14, No. 3, pp.897-902, July 1999 https://doi.org/10.1109/61.772331
  8. IEEE Std 81.2-1991, IEEE Guide for Measurement of Impedance and Safety Characteristics of Large, Extended or Interconnected Grounding System, IEEE Inc, pp.20-40
  9. IEEE Std 81-1983, IEEE Guide for Measuring Earth Resistivity, Ground Impedance and Earth Surface Potentials of a Ground System, IEEE Inc, pp.20-40, 1983
  10. W. C. Boaventura, P. S. A. Rocha and F. C. Dart, 'Testing and Evaluating Grounding Systems of High Voltage Energized Substations : Alternative Approaches', IEEE Trans., Vol. PD-14, No. 3, pp.923-927, July 1999 https://doi.org/10.1109/61.772335
  11. IEEE Std 80-2000, IEEE Guide for Safety in AC Substation Grounding, IEEE Inc., pp.113-115, 2000
  12. J. C. Balda, A. R. Oliva, D. W. McNabb and R. D. Richardson, 'Measurements of Neutral Currents and Voltages on a Distribution Feeder', IEEE Trans., Vol. PD-12, No. 4, Oct. 1997 https://doi.org/10.1109/61.634208
  13. A. B. Williams and F. J. Taylor, 'Electronic Filter Design Handbook', McGraw-Hill, Inc., pp.3.1-3.47, 1995