Lightning striking distance of complex structures

Traditionally, the location of lightning strike points has been determined by using the rolling sphere method, but recently the collection volume method (CVM) has also been proposed for the placement of air terminals on complex structures. Both these methods are empirical in nature and a more advanced model based on physics of discharges is needed to improve the state of affairs. This model is used to evaluate the striking distance from corners and air terminals on actual buildings and the results are qualitatively compared with the predictions of the rolling sphere method and the CVM. The results show that the striking distance not only depends upon the prospective return stroke current and the geometry of the building, but also on the lateral position of the downward leader with respect to the strike point. A further analysis is performed to qualitatively compare the lightning attraction zones obtained with the CVM and the leader inception zones obtained for a building with and without air terminals. The obtained results suggest that the collection volume concept overestimates the protection areas of air terminals placed on complex structures, bringing serious doubts on the validity of this method.

[1]  V. Cooray,et al.  A simplified physical model to determine the lightning upward connecting leader inception , 2006, IEEE Transactions on Power Delivery.

[2]  N. I. Petrov,et al.  Assessment of protection system positioning and models using observations of lightning strikes to structures , 2002, Proceedings of the Royal Society of London. Series A: Mathematical, Physical and Engineering Sciences.

[3]  A. M. Mousa.  Proposed research on the collection volume method/field intensification method for the placement of air terminals on structures , 2003, 2003 IEEE Power Engineering Society General Meeting (IEEE Cat. No.03CH37491).

[4]  V. Rakov,et al.  The lightning striking distance—Revisited , 2007 .

[5]  G. Carrara,et al.  Switching surge strength of large air gaps: A physical approach , 1976, IEEE Transactions on Power Apparatus and Systems.

[6]  E. R. Whitehead,et al.  Field and Analytical Studies of Transmission Line Shielding: Part , 1968 .

[7]  William H. Press,et al.  Numerical recipes in C. The art of scientific computing , 1987 .

[8]  Vernon Cooray,et al.  Identification of lightning vulnerability points on complex grounded structures , 2007 .

[9]  Vernon Cooray,et al.  Time dependent evaluation of the lightning upward connecting leader inception , 2006 .

[10]  A. J. Eriksson,et al.  An Improved Electrogeometric Model for Transmission Line Shielding Analysis , 1987, IEEE Transactions on Power Delivery.

[11]  Ronald B. Standler,et al.  Effects of coronae on electric fields beneath thunderstorms , 1979 .

[12]  R. T. Waters,et al.  Determination of the striking distance of lightning to earthed structures , 1995, Proceedings of the Royal Society of London. Series A: Mathematical and Physical Sciences.

[13]  E. Garbagnati,et al.  Lightning stroke simulation by means of the leader progression model. I. Description of the model and evaluation of exposure of free-standing structures , 1990 .

[14]  Franco D'Alessandro,et al.  A “Collection Volume Method” for the placement of air terminals for the protection of structures against lightning , 2001 .

[15]  N Szedenik.  Rolling sphere – method or theory? , 2001 .

[16]  F. D'alessandro,et al.  Field study on the interception efficiency of lightning protection systems and comparison with models , 2006, Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences.

[17]  Vernon Cooray,et al.  Effect of the space charge layer created by corona at ground level on the inception of upward lightning leaders from tall towers , 2007 .

[18]  Tamás Horváth.  Standardization of lightning protection based on the physics or on the tradition , 2004 .