Lightning protection guide by OBO

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Last revision 2020

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

Strana 183 z 288

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Sources include e.g.1. TBS Blitzschutz-Leitfaden 2018 / en / 2020/01/10 14:42:40 14:42:40 (LLExport_02613) / 2020/01/10 14:42:54 14:42:54 183 Chapter The internal lightning protection system .2. The voltage exceeds the maximum permissible nominal voltage, electronic devices are damaged and installed surge protection devices cannot protect against these long-lasting mains frequencies.2.1 Transient surges voltages Transient surges are short-lived surge voltages lasting for matter microseconds.3 Planning methods Part the lightning protection standard IEC 62305 describes how protect electrical and electronic sys- tems. 3. 3. Equipotential bonding necessary here avoid this charge separation.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 Example split Earth System: 50%–50% i kA; Ohm U 50,000 Ohm 50,000 V U Surge voltage i Lightning surge current R Earthing resistance The voltage resistance the components ex- ceeded and uncontrolled arcing occurs.2. 3. These surge voltages simulate surge currents (8/20 μs).1. motors, ballasts and industri- al loads.2. Lightning and switching operations generate large transient surges that can be prevented with surge protection devices.2 Static discharges (ESD: Electrostatic discharge) Electrostatic discharges are caused friction.2. 3.2. However, it can interfere with and destroy electronic compon- ents.2 Temporary and permanent surge voltages Temporary, transient, surge voltages occur due to faults the mains power supply. Only surge arrestors can safely arrest these dangerous voltages. When a person walks carpet, charge separation occurs – this instance, harmless humans. Mains frequency faults this kind can last for between sev- eral seconds and several hours. U1 Between phase (L1) and neutral conductor (N) U2 Between phase (L2) and neutral conductor (N) U3 Between phase (L3) and neutral conductor (N) U12 Between phase (L1) and phase (L2) U23 Between phase (L2) and phase (L3) U31 Between phase (L3) and phase (L1) Effect break neutral wire: neutral point displace- ment case asymmetry 3.2. 3. For example, a break neutral cable can generate impermiss- ible increase voltage the three-phase power sys- tem.2 Types surge voltages Transient, temporary and permanent surge voltages represent the three primary types surge voltages. They are the most common cause surge voltages.2.1 Switching operations (SEMP: Switching electromagnetic pulse) Switching operations occur due the switching of large inductive and capacitive loads, short circuits and interruptions the power system. The safety and installation standards IEC 60364 additionally stipulate that surge voltage protection measures are required important protective measure low-voltage systems