{"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\/da\/blog\/lightning-protection-of-low-voltage-power-distribution-system-in-buildings\/","title":{"rendered":"Lynbeskyttelse af lavsp\u00e6ndingsstr\u00f8mfordelingssystem i bygninger"},"content":{"rendered":"Lynkatastrofer omfatter hovedsageligt direkte lynnedslag, elektrostatisk lyninduktion og elektromagnetiske lynimpulser.\r\n\r\n<strong>Direkte lynnedslag<\/strong>\r\n\r\nDirekte lynnedslag refererer til det fysiske f\u00e6nomen, at tordenskyen udleder direkte til jorden. Hvis jorden bliver direkte ramt af lynet, vil der blive genereret en stor \u00f8jeblikkelig str\u00f8m p\u00e5 stedet for lynnedslaget. Hvis lynstr\u00f8mmen ikke kan udl\u00f8ses i tide, vil den genstand, der rammes af lynet, generere meget varme \u00f8jeblikkeligt, hvilket f\u00e5r objektet til at udvide sig, smelte, br\u00e6nde, eksplodere og andre skader. Typisk skal bygninger tage hensyn til farerne veddirekte lynnedslag.\r\n\r\n<strong>Lynelektrostatisk induktion<\/strong>\r\n\r\nLyninduktion betyder, at n\u00e5r en ladet tordensky dukker op p\u00e5 himlen, vil metallinjer, metalgenstande osv. under tordenskyen p\u00e5tage sig en elektrisk ladning modsat en tordensky ved elektrostatisk induktion. N\u00e5r et lyn opst\u00e5r, forsvinder tordenskyladningen hurtigt gennem lynnedslaget. Den inducerede ladning p\u00e5 metalledningen forplanter sig langs linjen og for\u00e5rsager forbig\u00e5ende oversp\u00e6nding ved enhedens linjeport. Hvis den inducerede ladning p\u00e5 metalgenstandenikke kan forsvinde med tiden, vil der v\u00e6re et eksternt udladningsf\u00e6nomen, som vil danne en gnist.\r\n\r\n<strong>Elektromagnetisk lynimpuls<\/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>Grundl\u00e6ggende lynbeskyttelsesforanstaltninger<\/strong>\r\n\r\nFor lavsp\u00e6ndingsstr\u00f8mfordelingssystemer er de almindeligt anvendte afledermodeller og parametre som f\u00f8lger:\r\n\r\n<strong>Klasse I trefaset str\u00f8m SPD (til 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>Klasse I trefaset str\u00f8m SPD (til 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>Klasse I trefaset str\u00f8m SPD (til 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>Klasse II trefaset str\u00f8m SPD (til TN-S eller TN-C-S systemer)<\/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>Klasse II trefaset str\u00f8m SPD (til 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>Lynbeskyttelsen af \u200b\u200blavsp\u00e6ndingsstr\u00f8mdistributionssystemet er som f\u00f8lger:<\/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\/da\/wp-json\/wp\/v2\/blog\/844","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.britecelectric.com\/da\/wp-json\/wp\/v2\/blog"}],"about":[{"href":"https:\/\/www.britecelectric.com\/da\/wp-json\/wp\/v2\/types\/blog"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.britecelectric.com\/da\/wp-json\/wp\/v2\/media\/845"}],"wp:attachment":[{"href":"https:\/\/www.britecelectric.com\/da\/wp-json\/wp\/v2\/media?parent=844"}],"wp:term":[{"taxonomy":"blog_category","embeddable":true,"href":"https:\/\/www.britecelectric.com\/da\/wp-json\/wp\/v2\/blog_category?post=844"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}