{"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\/fi\/blog\/lightning-protection-of-low-voltage-power-distribution-system-in-buildings\/","title":{"rendered":"Rakennusten pienj\u00e4nnites\u00e4hk\u00f6njakeluj\u00e4rjestelm\u00e4n ukkossuojaus"},"content":{"rendered":"Salamakatastrofit sis\u00e4lt\u00e4v\u00e4t p\u00e4\u00e4asiassa suoria salamaniskuja, salaman s\u00e4hk\u00f6staattista induktiota ja salaman s\u00e4hk\u00f6magneettisia pulsseja.\r\n\r\n<strong>Suora salamanisku<\/strong>\r\n\r\nSuoralla salamaniskulla tarkoitetaan fyysist\u00e4 ilmi\u00f6t\u00e4, jonka ukkospilvi purkautuu suoraan maahan. Jos salama iskee suoraan maahan, syntyy suuri hetkellinen virta salamaniskupaikassa. Jos salamavirtaa ei voida vapauttaa ajoissa, salaman osuma esine tuottaa v\u00e4litt\u00f6m\u00e4sti paljon l\u00e4mp\u00f6\u00e4, mik\u00e4 saa kohteen laajenemaan, sulamaan, palamaan, r\u00e4j\u00e4ht\u00e4m\u00e4\u00e4n ja muita vaurioita. Yleens\u00e4 rakennuksissa on otettava huomioon vaaratsuorat salamaniskut.\r\n\r\n<strong>Salaman s\u00e4hk\u00f6staattinen induktio<\/strong>\r\n\r\nSalaman induktio tarkoittaa, ett\u00e4 kun varautunut ukkospilvi ilmaantuu taivaalle, metalliviivat, metalliesineet jne. ukkospilven alla ottavat s\u00e4hk\u00f6staattisen induktion avulla s\u00e4hk\u00f6varauksen, joka on p\u00e4invastainen kuin ukkospilven. Kun salama iskee, ukkospilven varaus katoaa nopeasti salamaniskun kautta. Metallijohdon indusoitunut varaus etenee linjaa pitkin aiheuttaen ohimenev\u00e4n ylij\u00e4nnitteen laitteen linjaportissa. Jos indusoitunut varaus metalliesineeseenei voi kadota ajoissa, syntyy ulkoinen purkausilmi\u00f6, joka muodostaa kipin\u00e4n.\r\n\r\n<strong>Salaman s\u00e4hk\u00f6magneettinen pulssi<\/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>Perus ukkossuojaustoimenpiteet<\/strong>\r\n\r\nPienj\u00e4nnitteisiss\u00e4 tehonjakeluj\u00e4rjestelmiss\u00e4 yleisesti k\u00e4ytetyt pys\u00e4ytinmallit ja parametrit ovat seuraavat:\r\n\r\n<strong>Luokan I kolmivaiheinen teho SPD (TN-S-j\u00e4rjestelm\u00e4lle)<\/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>Luokan I kolmivaiheinen teho SPD (TN-C-j\u00e4rjestelm\u00e4lle)<\/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>Luokan I kolmivaiheinen teho SPD (TT-j\u00e4rjestelm\u00e4lle)<\/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>Luokan II kolmivaiheinen teho SPD (TN-S- tai TN-C-S-j\u00e4rjestelmille)<\/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>Luokan II kolmivaiheinen teho SPD (TT-j\u00e4rjestelm\u00e4lle)<\/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>Pienj\u00e4nniteverkon ukkossuojaus on seuraava:<\/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\/fi\/wp-json\/wp\/v2\/blog\/844","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.britecelectric.com\/fi\/wp-json\/wp\/v2\/blog"}],"about":[{"href":"https:\/\/www.britecelectric.com\/fi\/wp-json\/wp\/v2\/types\/blog"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.britecelectric.com\/fi\/wp-json\/wp\/v2\/media\/845"}],"wp:attachment":[{"href":"https:\/\/www.britecelectric.com\/fi\/wp-json\/wp\/v2\/media?parent=844"}],"wp:term":[{"taxonomy":"blog_category","embeddable":true,"href":"https:\/\/www.britecelectric.com\/fi\/wp-json\/wp\/v2\/blog_category?post=844"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}