{"id":758,"date":"2023-12-19T20:49:46","date_gmt":"2023-12-19T12:49:46","guid":{"rendered":"https:\/\/www.britecelectric.com\/?post_type=blog&p=758"},"modified":"2024-09-05T16:35:18","modified_gmt":"2024-09-05T08:35:18","slug":"low-voltage-power-supply-systems","status":"publish","type":"blog","link":"https:\/\/www.britecelectric.com\/pt\/blog\/low-voltage-power-supply-systems\/","title":{"rendered":"Sistemas de alimenta\u00e7\u00e3o de baixa tens\u00e3o"},"content":{"rendered":"Terminologia IEC<\/strong>\r\n\r\nInternational standard IEC 60364 distinguishes three families of earthing arrangements, using the two-letter codes TN, TT, and IT.\r\n\r\nThe first letter indicates the connection between earth and the power-supply equipment (generator or transformer):\r\n\r\n\u201cT\u201d \u2014 Direct connection of a point with earth\r\n\r\n\u201cI\u201d \u2014 No point is connected with earth, except perhaps via high impedance.\r\n\r\nThe second letter indicates the connection between earth or network and the electrical device being supplied:\r\n\r\n\u201cT\u201d \u2014 Earth connection is by a local direct connection to earth, usually via a ground rod.\r\n\r\n\u201cN\u201d \u2014 the earth connection is supplied by the electricity supply network, either separately to the neutral conductor (TN-S), combined with the neutral conductor (TN-C), or both (TN-C-S). These are discussed below.\r\n\r\nTipos de redes TN<\/strong>\r\n\r\nIn a TN earthing system, one of the points in the generator or transformer is connected with earth, usually the star point in a three-phase system. The body of the electrical device is connected with earth via this earth connection at the transformer. This arrangement is a current standard for residential and industrial electric systems particularly in Europe.\r\n\r\nThe conductor that connects the exposed metallic parts of the consumer\u2019s electrical installation is called protective earth (PE; see also: Ground). The conductor that connects to the star point in a three-phase system, or that carries the return current in a single-phase system, is called neutral (N). Three variants of TN systems are distinguished:\r\n\r\nTN-S<\/strong>\r\n\r\nPE e N s\u00e3o condutores separados que s\u00e3o conectados juntos apenas perto da fonte de alimenta\u00e7\u00e3o.\r\n\r\n\"\"\r\n\r\nTN-C<\/strong>\r\n\r\nUm condutor PEN combinado cumpre as fun\u00e7\u00f5es de um condutor PE e de um condutor N. (Em sistemas 230\/400 V normalmente usados \u200b\u200bapenas para redes de distribui\u00e7\u00e3o)\r\n\r\n\"\"\r\n\r\nTN-C-S<\/strong>\r\n\r\nParte do sistema usa um condutor PEN combinado, que em algum ponto \u00e9 dividido em linhas PE e N separadas. O condutor PEN combinado normalmente ocorre entre a subesta\u00e7\u00e3o e o ponto de entrada no edif\u00edcio, e o terra e o neutro s\u00e3o separados na cabe\u00e7a de servi\u00e7o. No Reino Unido, este sistema tamb\u00e9m \u00e9 conhecido como aterramento m\u00faltiplo de prote\u00e7\u00e3o (PME), devido \u00e0 pr\u00e1tica de conectar o condutor combinado neutro e terra atrav\u00e9s da rota mais curta poss\u00edvel \u00e0s hastes de aterramento locais na fonte.e em intervalos ao longo das redes de distribui\u00e7\u00e3o para cada local, para fornecer tanto o aterramento do sistema quanto o aterramento do equipamento em cada um desses locais. Sistemas semelhantes na Austr\u00e1lia e na Nova Zel\u00e2ndia s\u00e3o designados como neutro aterrado m\u00faltiplo (MEN) e, na Am\u00e9rica do Norte, como neutro multiaterrado (MGN).\r\n\r\n\"\"\r\n\r\nRede TT<\/strong>\r\n\r\nEm um sistema de aterramento TT, a conex\u00e3o de aterramento de prote\u00e7\u00e3o para o consumidor \u00e9 fornecida por um eletrodo de aterramento local, e h\u00e1 outro instalado de forma independente no gerador. N\u00e3o h\u00e1 \u2018fio terra\u2019 entre os dois. A imped\u00e2ncia do circuito de falha \u00e9 maior e, a menos que a imped\u00e2ncia do eletrodo seja realmente muito baixa, uma instala\u00e7\u00e3o TT deve sempre ter um RCD (GFCI) como seu primeiro isolador.\r\n\r\n\"\"\r\n\r\nRede de TI<\/strong>\r\n\r\nNuma rede inform\u00e1tica, o sistema de distribui\u00e7\u00e3o el\u00e9ctrica n\u00e3o tem qualquer liga\u00e7\u00e3o \u00e0 terra ou tem apenas uma liga\u00e7\u00e3o de alta imped\u00e2ncia.\r\n\r\n\"\"","protected":false},"featured_media":780,"parent":0,"menu_order":183,"template":"","meta":{"_acf_changed":false},"blog_category":[8],"class_list":["post-758","blog","type-blog","status-publish","has-post-thumbnail","hentry","blog_category-company-news"],"acf":{"des":"International standard IEC 60364 distinguishes three families of earthing arrangements, using the two-letter codes TN, TT, and IT.","txt":"IEC terminology<\/strong>\r\n\r\nInternational standard IEC 60364 distinguishes three families of earthing arrangements, using the two-letter codes TN, TT, and IT.\r\n\r\nThe first letter indicates the connection between earth and the power-supply equipment (generator or transformer):\r\n\r\n\u201cT\u201d \u2014 Direct connection of a point with earth\r\n\r\n\u201cI\u201d \u2014 No point is connected with earth, except perhaps via high impedance.\r\n\r\nThe second letter indicates the connection between earth or network and the electrical device being supplied:\r\n\r\n\u201cT\u201d \u2014 Earth connection is by a local direct connection to earth, usually via a ground rod.\r\n\r\n\u201cN\u201d \u2014 the earth connection is supplied by the electricity supply network, either separately to the neutral conductor (TN-S), combined with the neutral conductor (TN-C), or both (TN-C-S). These are discussed below.\r\n\r\nTypes of TN networks<\/strong>\r\n\r\nIn a TN earthing system, one of the points in the generator or transformer is connected with earth, usually the star point in a three-phase system. The body of the electrical device is connected with earth via this earth connection at the transformer. This arrangement is a current standard for residential and industrial electric systems particularly in Europe.\r\n\r\nThe conductor that connects the exposed metallic parts of the consumer\u2019s electrical installation is called protective earth (PE; see also: Ground). The conductor that connects to the star point in a three-phase system, or that carries the return current in a single-phase system, is called neutral (N). Three variants of TN systems are distinguished:\r\n\r\nTN\u2212S<\/strong>\r\n\r\nPE and N are separate conductors that are connected together only near the power source.\r\n\r\n\"\"\r\n\r\nTN\u2212C<\/strong>\r\n\r\nA combined PEN conductor fulfills the functions of both a PE and an N conductor. (On 230\/400 V systems normally only used for distribution networks)\r\n\r\n\"\"\r\n\r\nTN\u2212C\u2212S<\/strong>\r\n\r\nPart of the system uses a combined PEN conductor, which is at some point split up into separate PE and N lines. The combined PEN conductor typically occurs between the substation and the entry point into the building, and earth and neutral are separated in the service head. In the UK, this system is also known as protective multiple earthing (PME), because of the practice of connecting the combined neutral-and-earth conductor via the shortest practicable route to local earth rods at the source and at intervals along the distribution networks to each premises, to provide both system earthing and equipment earthing at each of these locations. Similar systems in Australia and New Zealand are designated as multiple earthed neutral (MEN) and, in North America, as multi-grounded neutral (MGN).\r\n\r\n\"\"\r\n\r\nTT network<\/strong>\r\n\r\nIn a TT earthing system, the protective earth connection for the consumer is provided by a local earth electrode, and there is another independently installed at the generator. There is no \u2018earth wire\u2019 between the two. The fault loop impedance is higher, and unless the electrode impedance is very low indeed, a TT installation should always have an RCD (GFCI) as its first isolator.\r\n\r\n\"\"\r\n\r\nIT network<\/strong>\r\n\r\nIn an IT network, the electrical distribution system has no connection to earth at all, or it has only a high-impedance connection.\r\n\r\n\"\""},"_links":{"self":[{"href":"https:\/\/www.britecelectric.com\/pt\/wp-json\/wp\/v2\/blog\/758","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.britecelectric.com\/pt\/wp-json\/wp\/v2\/blog"}],"about":[{"href":"https:\/\/www.britecelectric.com\/pt\/wp-json\/wp\/v2\/types\/blog"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.britecelectric.com\/pt\/wp-json\/wp\/v2\/media\/780"}],"wp:attachment":[{"href":"https:\/\/www.britecelectric.com\/pt\/wp-json\/wp\/v2\/media?parent=758"}],"wp:term":[{"taxonomy":"blog_category","embeddable":true,"href":"https:\/\/www.britecelectric.com\/pt\/wp-json\/wp\/v2\/blog_category?post=758"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}