{"id":844,"date":"2023-12-18T15:08:31","date_gmt":"2023-12-18T07:08:31","guid":{"rendered":"https:\/\/www.britecelectric.com\/?post_type=blog&#038;p=844"},"modified":"2024-09-05T16:32:04","modified_gmt":"2024-09-05T08:32:04","slug":"lightning-protection-of-low-voltage-power-distribution-system-in-buildings","status":"publish","type":"blog","link":"https:\/\/www.britecelectric.com\/it\/blog\/lightning-protection-of-low-voltage-power-distribution-system-in-buildings\/","title":{"rendered":"Protezione contro i fulmini del sistema di distribuzione dell'energia a bassa tensione negli edifici"},"content":{"rendered":"I disastri dovuti ai fulmini comprendono principalmente fulmini diretti, induzione elettrostatica dei fulmini e impulsi elettromagnetici dei fulmini.\r\n\r\n<strong>Fulmine diretto<\/strong>\r\n\r\nLa fulminazione diretta si riferisce al fenomeno fisico per cui la nube temporalesca scarica direttamente al suolo. Se il terreno viene colpito direttamente da un fulmine, nel punto in cui si \u00e8 verificato il fulmine verr\u00e0 generata una grande corrente istantanea. Se la corrente del fulmine non pu\u00f2 essere rilasciata in tempo, l'oggetto colpito dal fulmine generer\u00e0 molto calore istantaneamente, causando l'espansione, la fusione, la combustione, l'esplosione e altri danni dell'oggetto. In genere, gli edifici devono considerare i rischi difulmini diretti.\r\n\r\n<strong>Induzione elettrostatica del fulmine<\/strong>\r\n\r\nL'induzione del fulmine significa che quando una nube temporalesca carica appare nel cielo, linee metalliche, oggetti metallici, ecc. sotto la nube temporalesca assumono una carica elettrica opposta a quella di una nube temporalesca mediante induzione elettrostatica. Quando si verifica un fulmine, la carica della nube temporalesca scompare rapidamente a causa del fulmine. La carica indotta sulla linea metallica si propaga lungo la linea, provocando una sovratensione transitoria sulla porta di linea del dispositivo. Se la carica indotta sull'oggetto metalliconon pu\u00f2 scomparire in tempo, si verificher\u00e0 un fenomeno di scarica esterna, che former\u00e0 una scintilla.\r\n\r\n<strong>Impulso elettromagnetico del fulmine<\/strong>\r\n\r\nLightning electromagnetic pulse refers to the instantaneous formation of a lightning electromagnetic field in the area where the lightning strike occurs due to the extremely large peak value and speed of the lightning current. Under the action of the changing lightning electromagnetic field, metal lines in the area induce instantaneous lightning current. If the lightning current penetrates into the power supply line and communication line, transient overvoltage may occur on the device\u2019s line port.\r\n\r\nLightning protection of low-voltage power distribution system is to prevent the low-voltage power distribution system from introducing lightning current from lines outside the building.\r\n\r\n<strong>Misure fondamentali di protezione contro i fulmini<\/strong>\r\n\r\nPer i sistemi di distribuzione dell'energia a bassa tensione, i modelli e i parametri di scaricatori comunemente utilizzati sono i seguenti:\r\n\r\n<strong>SPD di potenza trifase di classe I (per sistema TN-S)<\/strong>\r\n\r\nModel: BR-25GR 4P\r\n\r\nMax. continuous operating voltage: 275V~\r\n\r\nLightning impulse current: 25kA (10\/350\u03bcs)\r\n\r\nNominal discharge current: 25kA (8\/20\u03bcs)\r\n\r\nMax. discharge current: 100kA (8\/20\u03bcs)\r\n\r\nMain function: installed in the main power distribution cabinet, as the first-level lightning protection of the power line.\r\n\r\n<strong>SPD di potenza trifase di classe I (per sistema TN-C)<\/strong>\r\n\r\nModel: BR-25GR 3P\r\n\r\nMax. continuous operating voltage: 275V~\r\n\r\nLightning impulse current: 25kA (10\/350\u03bcs)\r\n\r\nNominal discharge current: 25kA (8\/20\u03bcs)\r\n\r\nMax. discharge current: 100kA (8\/20\u03bcs)\r\n\r\nMain function: installed in the main power distribution cabinet, as the first-level lightning protection of the power line.\r\n\r\n<strong>SPD di potenza trifase classe I (per sistema TT)<\/strong>\r\n\r\nModel: BR-25GR 3P+NPE\r\n\r\nMax. Continuous operating voltage: 275V~\r\n\r\nLightning impulse current: 25Ka\/50kA (10\/350\u03bcs)\r\n\r\nNominal discharge current: 25kA\/50kA (8\/20\u03bcs)\r\n\r\nMax. discharge current: 100kA (8\/20\u03bcs)\r\n\r\nMain function: installed in the main power distribution cabinet, as the first-level lightning protection of the power line.\r\n\r\n<strong>SPD di potenza trifase di classe II (per sistemi TN-S o TN-C-S)<\/strong>\r\n\r\nModel: BR-40 4P\r\n\r\nMax. continuous operating voltage: 275V~\r\n\r\nNominal discharge current: 20kA (8\/20\u03bcs)\r\n\r\nMax. discharge current: 40kA (8\/20\u03bcs)\r\n\r\nMain function: installed in the sub-power distribution box, as the second-level lightning protection of the power line.\r\n\r\n<strong>SPD di potenza trifase di classe II (per sistema TT)<\/strong>\r\n\r\nModel: BR-40 3P+NPE\r\n\r\nMax. continuous operating voltage: 275V~\r\n\r\nNominal discharge current: 20kA (8\/20\u03bcs)\r\n\r\nMax. discharge current: 40kA (8\/20\u03bcs)\r\n\r\nMain function: installed in the sub-power distribution box, as the second-level lightning protection of the power line.\r\n\r\n<strong>La protezione contro i fulmini del sistema di distribuzione dell'energia a bassa tensione \u00e8 la seguente:<\/strong>\r\n\r\nThe main power distribution cabinet of the building is installed with a Class I power SPD as the first-level lightning protection of the power line.\r\n\r\nThe secondary power distribution cabinet (box) of the building is installed with a Class II power SPD as the second-level lightning protection of the power line.\r\n\r\nThe tertiary power distribution cabinet (box) of the building is installed with a Class II power SPD as the third-level lightning protection of the power line.\r\n\r\nFor important equipment ports, install Class III power SPD as terminal-level lightning protection for power lines.","protected":false},"featured_media":845,"parent":0,"menu_order":155,"template":"","meta":{"_acf_changed":false},"blog_category":[8],"class_list":["post-844","blog","type-blog","status-publish","has-post-thumbnail","hentry","blog_category-company-news"],"acf":{"des":"Lightning disasters mainly include direct lightning strikes, lightning electrostatic induction, and lightning electromagnetic pulses.","txt":"Lightning disasters mainly include direct lightning strikes, lightning electrostatic induction, and lightning electromagnetic pulses.\r\n\r\n<strong>Direct lightning strike<\/strong>\r\n\r\nDirect lightning strike refers to the physical phenomenon that the thundercloud discharges directly to the ground. If the ground is directly struck by lightning, a large instantaneous current will be generated at the location of the lightning strike. If the lightning current cannot be released in time, the object struck by the lightning will generate a lot of heat instantly, causing the object to expand, melt, burn, explode and other damage. Typically, buildings must consider the hazards of direct lightning strikes.\r\n\r\n<strong>Lightning electrostatic induction<\/strong>\r\n\r\nLightning induction means that when a charged thundercloud appears in the sky, metal lines, metal objects, etc. under the thundercloud to take on an electric charge opposite to that of a thundercloud by electrostatic induction. When a lightning strike occurs, the thundercloud charge quickly disappears through the lightning strike. The induced charge on the metal line propagates along the line, causing transient overvoltage at the line port of the device. If the induced charge on the metal object cannot disappear in time, there will be an external discharge phenomenon, which will form a spark.\r\n\r\n<strong>Lightning electromagnetic pulse<\/strong>\r\n\r\nLightning electromagnetic pulse refers to the instantaneous formation of a lightning electromagnetic field in the area where the lightning strike occurs due to the extremely large peak value and speed of the lightning current. Under the action of the changing lightning electromagnetic field, metal lines in the area induce instantaneous lightning current. If the lightning current penetrates into the power supply line and communication line, transient overvoltage may occur on the device\u2019s line port.\r\n\r\nLightning protection of low-voltage power distribution system is to prevent the low-voltage power distribution system from introducing lightning current from lines outside the building.\r\n\r\n<strong>Basic lightning protection measures<\/strong>\r\n\r\nFor low-voltage power distribution systems, the commonly used arrester models and parameters are as follows:\r\n\r\n<strong>Class I three-phase power SPD (for TN-S system)<\/strong>\r\n\r\nModel: BR-25GR 4P\r\n\r\nMax. continuous operating voltage: 275V~\r\n\r\nLightning impulse current: 25kA (10\/350\u03bcs)\r\n\r\nNominal discharge current: 25kA (8\/20\u03bcs)\r\n\r\nMax. discharge current: 100kA (8\/20\u03bcs)\r\n\r\nMain function: installed in the main power distribution cabinet, as the first-level lightning protection of the power line.\r\n\r\n<strong>Class I three-phase power SPD (for TN-C system)<\/strong>\r\n\r\nModel: BR-25GR 3P\r\n\r\nMax. continuous operating voltage: 275V~\r\n\r\nLightning impulse current: 25kA (10\/350\u03bcs)\r\n\r\nNominal discharge current: 25kA (8\/20\u03bcs)\r\n\r\nMax. discharge current: 100kA (8\/20\u03bcs)\r\n\r\nMain function: installed in the main power distribution cabinet, as the first-level lightning protection of the power line.\r\n\r\n<strong>Class I three-phase power SPD (for TT system)<\/strong>\r\n\r\nModel: BR-25GR 3P+NPE\r\n\r\nMax. Continuous operating voltage: 275V~\r\n\r\nLightning impulse current: 25Ka\/50kA (10\/350\u03bcs)\r\n\r\nNominal discharge current: 25kA\/50kA (8\/20\u03bcs)\r\n\r\nMax. discharge current: 100kA (8\/20\u03bcs)\r\n\r\nMain function: installed in the main power distribution cabinet, as the first-level lightning protection of the power line.\r\n\r\n<strong>Class II three-phase power SPD (for TN-S or TN-C-S systems)<\/strong>\r\n\r\nModel: BR-40 4P\r\n\r\nMax. continuous operating voltage: 275V~\r\n\r\nNominal discharge current: 20kA (8\/20\u03bcs)\r\n\r\nMax. discharge current: 40kA (8\/20\u03bcs)\r\n\r\nMain function: installed in the sub-power distribution box, as the second-level lightning protection of the power line.\r\n\r\n<strong>Class II three-phase power SPD (for TT system)<\/strong>\r\n\r\nModel: BR-40 3P+NPE\r\n\r\nMax. continuous operating voltage: 275V~\r\n\r\nNominal discharge current: 20kA (8\/20\u03bcs)\r\n\r\nMax. discharge current: 40kA (8\/20\u03bcs)\r\n\r\nMain function: installed in the sub-power distribution box, as the second-level lightning protection of the power line.\r\n\r\n<strong>The lightning protection of the low-voltage power distribution system is as follows:<\/strong>\r\n\r\nThe main power distribution cabinet of the building is installed with a Class I power SPD as the first-level lightning protection of the power line.\r\n\r\nThe secondary power distribution cabinet (box) of the building is installed with a Class II power SPD as the second-level lightning protection of the power line.\r\n\r\nThe tertiary power distribution cabinet (box) of the building is installed with a Class II power SPD as the third-level lightning protection of the power line.\r\n\r\nFor important equipment ports, install Class III power SPD as terminal-level lightning protection for power lines."},"_links":{"self":[{"href":"https:\/\/www.britecelectric.com\/it\/wp-json\/wp\/v2\/blog\/844","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.britecelectric.com\/it\/wp-json\/wp\/v2\/blog"}],"about":[{"href":"https:\/\/www.britecelectric.com\/it\/wp-json\/wp\/v2\/types\/blog"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.britecelectric.com\/it\/wp-json\/wp\/v2\/media\/845"}],"wp:attachment":[{"href":"https:\/\/www.britecelectric.com\/it\/wp-json\/wp\/v2\/media?parent=844"}],"wp:term":[{"taxonomy":"blog_category","embeddable":true,"href":"https:\/\/www.britecelectric.com\/it\/wp-json\/wp\/v2\/blog_category?post=844"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}