Lightning protection guide by OBO

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Last revision 2020

Vydal: OBO BETTERMANN s. r. o. Autor: OBO BETTERMANN

Strana 21 z 288

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The area under the current-time curve for surge cur- rents indicates the amount charge. Surge arresters type and type are impacted with this test impulse.TBS Blitzschutz-Leitfaden 2018 / en / 2020/01/10 14:42:40 14:42:40 (LLExport_02613) / 2020/01/10 14:42:54 14:42:54 Pulse shape Direct lightning strike, 10/350 simu- lated lightning pulse Pulse shape Remote lightning strike switching op- eration, 8/20 simulated current pulse (surge voltage) Types pulse and their characteristics 1. The charge of the lightning test current waveform 10/350 roughly corresponds times the charge surge current of waveform 8/20 with the same amplitude. Remote lightning strikes switching operations: Pulse shape 2 The surges created remote lightning strikes and switching operations are imitated with test impulse 8/20 μs. building with external lightning protection receives direct hit, voltage drop occurs the earthing resistance the lightning protection equipo- tential bonding system, which represents surge voltage against the distant environment.4 Test currents and simulated surge voltages High lightning currents can flow the ground during a storm. The energy content this impulse signific- antly lower than the lightning test current surge cur- rent wave 10/350 μs. Example: • Lightning current (i): 100 kA • Earthing resistance (R): Ω • Voltage drop (u): R 100 100,000 V Conclusion: The voltage between the earthing resistance and the remotely earthed network increases 100 kV. Direct lightning strike: Pulse shape 1 Lightning currents that can occur during direct light- ning strike can imitated with the surge current of waveform 10/350 μs. The lightning test current imit- ates both the fast rise and the high energy content of natural lightning. Suitable test currents for testing different lightning and surge protectors have been defined in national and international standards. This rise potential poses threat the electrical systems (e.g. voltage supply, telephone systems, cable TV, control cables, etc. TBS Blitzschutz-Leitfaden 2018 / en / 2020/01/10 14:42:40 14:42:40 (LLExport_02613) / 2020/01/10 14:42:54 14:42:54 21 Chapter General introduction . Type lightning current arresters and external lightning protection components are tested using this pulse.) that are routed into the building