Hľadanie: Triumphs and Turbulence EN
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Vnější a vnitřní ochrana před bleskem (3. aktualizované vydání)
Třetí vydání této velmi žádané příručky vychází z druhé edice souboru ČSN EN 62305 a je aktualizováno podle norem platných k 1. 1. 2020.
Autor toto téma podává logicky a srozumitelně a velký důraz klade při návrhu jak vnější, tak i vnitřní ochrany před bleskem a přepětím na využití výpočetní techniky. V současné době totiž existuje celá řada programů, které elektrotechnikům podstatně usnadňují práci např. při výpočtu rizik.
Norma pro realizaci každé části systému ochrany nabízí několik variant. Žádná z nich není univerzálně platná pro každou situaci. Tato příručka je průvodcem při návrhu hromosvodu a přepěťových ochran. Povede vás za ruku přes jednotlivé křižovatky a ukáže vám výhody a nevýhody jednotlivých cest směrů. Poté, co se rozhodnete, kterým směrem pokračovat, nabídne vám konkrétní, praktické informace, které tak nemusíte držet v paměti.
Pro úspěšný návrh hromosvodu a ochran před přepětím je důležité pochopit logiku celého systému. Nelze vymyslet žádný univerzální postup, podle kterého by se dal celý systém navrhnout. Systém ochrany nebude nikdy navrhovat počítač, kde bychom vložili odpovědi na spoustu otázek. Každý dobrý systém bude navržen člověkem, který ví, co je jeho cílem, ví, jak věci fungují, a dokáže si představit, co se při úderu blesku děje.
Příručka je rozdělena na dvě části.
První část pojednává o blesku a dějích na jeho cestě do země. Dále také o výpočtu rizika, ale hlavně o vnějším LPS neboli o jímačích, svodech, uzemnění a pospojování. Vše z norem ČSN EN 62305-1 až 3 ed. 2.
Druhá část se zabývá ČSN EN 62305-4 ed. 2 a doplňuje mnoho praktických informací souvisejících s instalací vnitřního systému, hlavně svodičů přepětí.
Příručka předpokládá, že čtenář má základní znalosti jak teoretické elektrotechniky, tak i příslušných norem. Jejím účelem totiž není opisovat text norem, ale podat vysvětlení jejich ustanovení a doplnit je dalšími informacemi, které autor pokládá za důležité. Je ale doplněna řadou názorných obrázků a tabulek.
V závěru příručky jsou 4 přílohy:
- příklad zprávy o revizi vnější ochrany před bleskem (hromosvodu),
- příklad zprávy o revizi vnitřního systému ochrany proti přepětí,
- praktická pomůcka Ochrana před bleskem podle souboru ČSN EN 62305,
- praktická pomůcka Přibližné hodnoty odporu zemničů podle jejich rozměrů a charakteru půdy.
Kniha je určena projektantům, montérům i provozovatelům (včetně revizních techniků) vnějších i vnitřních ochran před bleskem. Je též vhodná jako základní literatura pro vzdělávání elektrotechniků na odborných středních i vysokých školách i pro přípravu elektrotechniků ke zkouškám a přezkoušení jejich odborné způsobilosti.
Obsah:
ČÁST PRVNÍ: VNĚJŠÍ SYSTÉM OCHRANY PŘED BLESKEM - HROMOSVOD
1. NÁZVOSLOVÍ
2. PROTI ČEMU SE CHRÁNÍME STAVBOU HROMOSVODU
2.1 Jiskření
2.2 Proud
2.3 Elektromagnetické pole
2.4 Napětí
2.5 Dynamické účinky
3. VÝPOČET RIZIKA A STANOVENÍ TŘÍDY LPS
3.1 Výsledky vypočteného rizika
3.2 Rozměry objektu sběrná plocha
3.3 Přítomnost osob
3.4 Podlaha
3.5 Riziko požáru
3.6 Služby veřejnosti
3.7 Stínění při LPZ 0/1
3.8 Stínění při LPZ 1/2 a 2/3
3.9 Provedení vedení (kabely stíněné, nestíněné, s a bez vyloučení indukčních smyček) 18
3.10 Transformátor na přívodním vedení
3.11 Rozměry objektu, ze kterého přívodní vedení nn přichází
4. VNĚJŠÍ LPS
4.1 Typ hromosvodu
4.1.1 Izolovaný (oddálený) hromosvod
4.1.2 Hromosvod upevněný na stavbě
4.2 Jímací soustava
4.2.1 Metoda valící se koule
4.2.2 Metoda ochranného úhlu
4.2.3 Metoda mřížové sítě
4.2.4 Další požadavky
4.2.5 Náhodné jímače
4.2.6 Ochrana střešních nadstaveb
4.3 Svody
4.4 Uzemnění
5. MATERIÁLY
5.1 (Ne)snášenlivost materiálů
6. VNITŘNÍ SYSTÉM OCHRANY PŘED BLESKEM (VNITŘNÍ LPS)
6.1 Ekvipotenciální pospojování proti blesku (EB)
6.2 Elektrická izolace vnějšího LPS
7. ÚDRŽBA A REVIZE
8. LPS V PŘÍPADECH STAVEB S PROSTORY S NEBEZPEČÍM VÝBUCHU
8.1 Názvosloví
8.2 Zásady
8.2.1 Základní požadavky
8.2.2 Stavby, kde se vyskytují tuhé výbušniny
8.2.3 Stavby s nebezpečnými prostory
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