Improved TL inductivity formula for analysis of grounding conductors

Electromagnetic Models (EM) for analysis of grounding systems are based on least possible approximations in the solution of Maxwell's equations. The complexity of the EM calculations motivated the creation of more engineer-oriented and less time consuming methods for analysis of grounding systems. One of the most commonly used methods is the transmission line (TL) model. In this paper a new, improved formula for the inductivity parameter of the TL model is proposed. The new formula is implemented to calculate the grounding impedance of vertical and horizontal grounding conductors, as well as the transient potential at feed point when a subsequent lightning stroke is injected. Comparison of the obtained results to the classical TL model shows a significant improvement in precision with reference to rigorous EM calculations.

[1]  N. Nagaoka,et al.  Application of the Partial Element Equivalent Circuit Method to Analysis of Transient Potential Rises in Grounding Systems , 2011, IEEE Transactions on Electromagnetic Compatibility.

[2]  Reinhold Rüdenberg.  Electrical Shock Waves in Power Systems: Traveling Waves in Lumped and Distributed Circuit Elements , 1968 .

[3]  D. Mukhedkar,et al.  Fundamental Considerations and Impluse Impedance of Grounding Grids , 1981, IEEE Transactions on Power Apparatus and Systems.

[4]  L. Grcev.  Dynamic behavior of grounding grids , 2003 .

[5]  E. Sunde.  Earth conduction effects in transmission systems , 1949 .

[6]  A. F. Otero,et al.  Frequency-dependent grounding system calculation by means of a conventional nodal analysis technique , 1999 .

[7]  Leonid Grcev,et al.  EMTP-based model for grounding system analysis , 1994 .

[8]  A. P. Meliopoulos,et al.  Frequency Dependent Characteristics of Grounding Systems , 1987, IEEE Power Engineering Review.

[9]  Leonid Grcev,et al.  An electromagnetic model for transients in grounding systems , 1990 .

[10]  S. Bourg,et al.  Deep earth electrodes in highly resistive ground: frequency behaviour , 1995, Proceedings of International Symposium on Electromagnetic Compatibility.

[11]  A. Zeddam,et al.  Harmonic Input Impedance of Earth Connections , 1984, 1984 International Symposium on Electromagnetic Compatibility.

[12]  Leonid Grcev,et al.  Computer analysis of transient voltages in large grounding systems , 1996 .

[13]  A. Liew,et al.  Dynamic model of impulse characteristics of concentrated earths , 1974 .

[14]  Farhad Rachidi,et al.  Current and electromagnetic field associated with lightning-return strokes to tall towers , 2001 .