{"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\/pl\/blog\/low-voltage-power-supply-systems\/","title":{"rendered":"Systemy zasilania niskiego napi\u0119cia"},"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\nRodzaje sieci 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 i N to oddzielne przewodniki, kt\u00f3re s\u0105 po\u0142\u0105czone ze sob\u0105 tylko w pobli\u017cu \u017ar\u00f3d\u0142a zasilania.\r\n\r\n\"\"\r\n\r\nTN-C<\/strong>\r\n\r\n\u0141\u0105czony przew\u00f3d PEN spe\u0142nia funkcje zar\u00f3wno przewodu PE, jak i przewodu N. (W systemach 230\/400 V zwykle u\u017cywanych tylko w sieciach dystrybucyjnych)\r\n\r\n\"\"\r\n\r\nTN-C-S<\/strong>\r\n\r\nCz\u0119\u015b\u0107 systemu wykorzystuje po\u0142\u0105czony przew\u00f3d PEN, kt\u00f3ry w pewnym momencie jest podzielony na osobne linie PE i N. Po\u0142\u0105czony przew\u00f3d PEN zwykle wyst\u0119puje pomi\u0119dzy podstacj\u0105 a punktem wej\u015bcia do budynku, a uziemienie i przew\u00f3d neutralny s\u0105 oddzielone w g\u0142owicy serwisowej. W Wielkiej Brytanii system ten jest r\u00f3wnie\u017c znany jako ochronne uziemienie wielokrotne (PME) ze wzgl\u0119du na praktyk\u0119 \u0142\u0105czenia po\u0142\u0105czonego przewodu neutralnego i uziemiaj\u0105cego najkr\u00f3tsz\u0105 mo\u017cliw\u0105 drog\u0105 z lokalnymi pr\u0119tami uziemiaj\u0105cymi u \u017ar\u00f3d\u0142aoraz w pewnych odst\u0119pach wzd\u0142u\u017c sieci dystrybucyjnej do ka\u017cdego obiektu, aby zapewni\u0107 uziemienie zar\u00f3wno systemu, jak i sprz\u0119tu w ka\u017cdym z tych miejsc. Podobne systemy w Australii i Nowej Zelandii s\u0105 oznaczone jako wielokrotnie uziemiony punkt neutralny (MEN), a w Ameryce P\u00f3\u0142nocnej jako wielouziemiony punkt neutralny (MGN).\r\n\r\n\"\"\r\n\r\nSie\u0107 TT<\/strong>\r\n\r\nW systemie uziemiaj\u0105cym TT uziemienie ochronne dla odbiorcy zapewnia lokalny uziom, a drugi jest niezale\u017cnie zainstalowany przy generatorze. Pomi\u0119dzy nimi nie ma \u2018przewodu uziemiaj\u0105cego\u2019. Impedancja p\u0119tli zwarcia jest wy\u017csza i je\u015bli impedancja elektrody nie jest rzeczywi\u015bcie bardzo niska, instalacja TT powinna zawsze mie\u0107 RCD (GFCI) jako pierwszy izolator.\r\n\r\n\"\"\r\n\r\nSie\u0107 informatyczna<\/strong>\r\n\r\nW sieci IT system dystrybucji energii elektrycznej nie ma \u017cadnego po\u0142\u0105czenia z ziemi\u0105 lub ma jedynie po\u0142\u0105czenie o wysokiej impedancji.\r\n\r\n\"\"","protected":false},"featured_media":780,"parent":0,"menu_order":147,"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\/pl\/wp-json\/wp\/v2\/blog\/758","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.britecelectric.com\/pl\/wp-json\/wp\/v2\/blog"}],"about":[{"href":"https:\/\/www.britecelectric.com\/pl\/wp-json\/wp\/v2\/types\/blog"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.britecelectric.com\/pl\/wp-json\/wp\/v2\/media\/780"}],"wp:attachment":[{"href":"https:\/\/www.britecelectric.com\/pl\/wp-json\/wp\/v2\/media?parent=758"}],"wp:term":[{"taxonomy":"blog_category","embeddable":true,"href":"https:\/\/www.britecelectric.com\/pl\/wp-json\/wp\/v2\/blog_category?post=758"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}