engleski

Stochastic assessment of external LPS of structures

This paper presents a stochastic algorithm for the efficiency assessment of external LPS (Lightning Protection System) of structures. Lightning strikes are simulated by means of the Monte Carlo method, with the application of electrogeometric model. Peak values of the lightning current have been subdivided into classes. In the stochastic model, LPS and structure can be approximated by a number of straight segments, triangles and plane quadrangles. Origin of the lightning strikes is located on the imaginary plane above the structure. Each lightning strike starts its descend on this plane and follows a stochastic path toward the protected structure or earth surface. Minimal distance from the lightning stroke stepped leader head to elements of LPS, structure and earth surface is computed after the each jump. If this distance is smaller then the striking distance, lightning will strike its nearest point belonging to the LPS, structure or the earth surface. Efficiency of the LPS is seen as quotient between the total number of lightning strikes ending up on LPS itself and the total number of lightning strikes ending up on LPS and structure. Lightning strikes hitting the earth surface are not counted. Total number of lightning strike simulations equals several hundred thousands for real world examples. A concrete example of stochastic efficiency assessment of external LPS of structure will be presented as well. Here presented algorithm could be equally successfully applied for the stochastic efficiency assessment of lightning protection systems of high voltage switchyards.

stochastic assesment; LPS; efficiency; Monte Carlo method

Zbornik s punim tekstom rada izdan je samo kao CD ROM. Prošireni sažeci radova objavljeni su u tiskanom zborniku Programme & Book of Extended Abstracts of the 29th International Conference on Lightning Protection ICLP 2008 ; str. 178