Calculating the Zones Protected by Complex Lightning Rods

Russian regulatory documents establish protection zones for a limited number of simple lightning rods, which are not enough for optimal lightning protection design of complex facilities. The article presents a numerical method for calculating the zones protected by complex lightning rods. The proposed method is based on replacing the lightning wire with a system of vertical rods. An analytical expression for the zone protected by a combined (wire–rod) lightning protection system is obtained. The zones protected by inclined wires, combined systems, and arbitrary wires are calculated. Using the example of a closed wire, the advantages of the developed technique in comparison with the regulatory documents currently in force are shown, namely, a more accurate solution (better smoothness of the protected zone outlines) by taking into account the mutual influence of all lightning rod system elements. V.M. Kuprienko’s proposal on choosing the maximum distance of a double rod system based on the rods active part is investigated, including the results of its application for calculating the protection zones of the Konda oil storage facility (before the accident in 2010).