06.08.14 , , , ,
A representative of the design institute appealed out company with the question of ensuring lightning protection of a football stadium in Moscow.
The stadium has a standard form, there are light posts with spotlights at the corners. It is planned to install lightning rods on these posts. The initial calculation of lightning protection was carried out according to IEC 62305-1: 2010 * "Lightning protection. Part 1. General Principles". According to the calculation results, the stadium field and, consequently, the players were not protected from lightning. In this regard, the idea to use active lightning rods came up. A request to ZANDZ experts was to check the solutions of installation of active lightning rods.
(The scale is not kept)
гостиница с выходом на поле – hotel with an exit to the field
трибуны – bleachers
прожекторы – spotlights
молниеприемники - lightning rods
зона защиты по СО – protection zone according to the industry standard
зона защиты по МЭК – protection zone according to EIC
ZANDZ experts gave the following conclusion: IEC 62305-1:2010*standard, which is used for the calculation of lightning protection zones in this project, doesn't take into account the mutual influence of lightning rods. When using national standards that are based on a statistical method for calculating the number of breakthroughs, protection of the stadium field is already carried out by lightning rods, installed on lighting towers at the four corners of the stadium.
Taking the density of lightning strikes into the ground - 6.0 strikes / sq km per year (standard value for the city of Moscow 4.0 strikes / sq km per year), we get the following calculated values: The total number of strikes into the system - 0.33 (once in 3 years) .
The total number of breakthroughs (strikes directly into the stadium field passing lightning rods) - 0.00033 (once in 3030 years).
Protection reliability - 0.999.
Based on these calculations, it is obvious that installation of active lightning rods will be unfeasible.
The calculations were performed using the software developed by "Krzhizhanovsky Power Engineering Institute" (JSC "ENIN") LLC. This software allows to calculate the expected number of lightning breaks to the object during a predetermined period of operation and determine protection reliability by means of an arbitrary system of lightning rods of various shapes and heights. The calculation is carried out on a statistical method based on the process of channel orientation and selection of a lightning strike point.
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