Lightning strike on overhead telephone line: A case study of tanzania telecommunication company limited (TTCL)

Recently there have been a growing concern over the lightning caused damages, and disturbances on the consumer operated equipments utilizing a telephone line. This concern has been attributed by the fact that most of today's consumers' equipments comprise of electronic devices or microprocessor controls that operate at low voltages, which can be superceded by even distant lightning strike. Lightning strike can be either direct or indirect, which causes induced voltage along the telephone lines when it strikes on to the line or at a distance from the line. In this paper the induced voltages on a conductor of 7 m height above the ground are calculated as a function of distance from the strike point using Finite Difference Time Domain (FDTD) method, as it could be a necessary data for deciding the possible future protection scheme. It has been shown that finitely conducting ground (lossy case) has pronounced effects for lightning surge propagation and induced amplitude overvoltages along the telephone line above the ground and can not be neglected in the calculations of the induced overvoltages along the line due to lightning strike compared to an infinitely conducting ground (lossless case).

[1]  M. Uman,et al.  Magnetic field of lightning return stroke , 1969 .

[2]  Farhad Rachidi,et al.  On the contribution of the electromagnetic field components in field-to-transmission line interaction , 1995 .

[3]  Ashok K. Agrawal,et al.  Transient Response of Multiconductor Transmission Lines Excited by a Nonuniform Electromagnetic Field , 1980 .

[4]  M. Ianoz,et al.  Transient analysis of multiconductor lines above a lossy ground , 1999 .

[5]  M. Ianoz,et al.  Lightning-induced voltages on overhead lines , 1993 .

[6]  Farhad Rachidi,et al.  Formulation of the field-to-transmission line coupling equations in terms of magnetic excitation field , 1993 .

[7]  C. Taylor,et al.  The response of a terminated two-wire transmission line excited by a nonuniform electromagnetic field , 1965 .

[8]  M. Darveniza,et al.  Lightning Performance of Unshielded Transmission Lines , 1982, IEEE Transactions on Power Apparatus and Systems.

[9]  M. Uman,et al.  Lightning return stroke current models with specified channel‐base current: A review and comparison , 1990 .

[10]  Clayton R. Paul,et al.  Analysis of Multiconductor Transmission Lines , 1994 .

[11]  M. Ianoz,et al.  Response of multiconductor power lines to nearby lightning return stroke electromagnetic fields , 1996 .

[12]  P. Degauque,et al.  Current and Voltage Induced on Telecommunication Cables by a Lightning Stroke , 1987 .

[13]  J. R. Carson Wave propagation in overhead wires with ground return , 1926 .

[14]  Lightning protection of Medium Voltage networks , 2005 .

[15]  Adam Semlyen,et al.  Ground Return Parameters of Transmission Lines an Asymptotic Analysis for Very High Frequencies , 1981, IEEE Transactions on Power Apparatus and Systems.

[16]  K. C. Chen,et al.  Accuracy of approximate transmission line formulas for overhead wires , 1989 .

[17]  D. Orzan,et al.  Time-domain low frequency approximation for the off-diagonal terms of the ground impedance matrix , 1997 .

[18]  M. Ianoz,et al.  On lightning return stroke models for LEMP calculations , 1988 .

[19]  M. Ianoz,et al.  Influence of a lossy ground on lightning-induced voltages on overhead lines , 1996 .

[20]  Wasyl Janischewskyj,et al.  IEEE working group report. Estimating lightning performance of transmission lines. II: Updates to analytical models , 1993 .

[21]  A. Eriksson,et al.  Lightning-Induced Overvoltages on Overhead Distribution Lines , 1982 .

[22]  Nelson Theethayi Electromagnetic Interference in Distributed Outdoor Electrical Systems, with an Emphasis on Lightning Interaction with Electrified Railway Network , 2005 .

[23]  R. H. Golde,et al.  The lightning discharge , 1941 .

[24]  A. Deri,et al.  The Complex Ground Return Plane a Simplified Model for Homogeneous and Multi-Layer Earth Return , 1981, IEEE Transactions on Power Apparatus and Systems.

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

[26]  Salvatore Celozzi,et al.  Direct time-domain analysis of transmission lines above a lossy ground , 2001 .

[27]  Farhad Rachidi,et al.  On the Master, Uman, Lin, Standler and the Modified Transmission Line Lightning return stroke current models , 1990 .