【正文】 otential such as being auxiliary in the distribution , wait for the wiring end son of the electric potential generally in the case cupboard. Must notice , should wire the end son and can expose 。t connect with PE line either.　In highpressure system , adopt neutral some person who connects place can make earth relay protection accurate movement and dispel singlephase electric arc earth overvoltage. Can prevent the skew of voltage of zero preface , keep the threephase voltage in a basic balance in some neutral earth, this is very meaningful to lowvoltage system, can be convenient to use the singlephase power. protection is grounded: Safe protection earth metal part and earth body with electricity make good metal join electric equipment. Namely power consuming equipment and some metal ponents near the equipment of building, join with PE thread, but forbid connecting PE line with N line. Indoor shielding should a lot of some is joined with PE thread reliably. It is very important too to defend static interference. In clean, dry room, walking , mobile device of people, is it can produce a large amount of static to grit each. For example 1020% environmental walking of middleman can gather volt of static voltages , have good earth in relative humidity, will not merely produce the interference to the electronic equipment , even will break the equipment chip . Bring static object or may produce object (insulator ) of static through lead static body and earth form electric earth of return circuit is it defend static earth to call. Defend static earth require of clean quiet dry environment, all equipment outer cover and getting indoor facility must with line many to join reliably a bit PE have.　Earth device of intelligent building little and kind earth resistance have, independent dyke thunder protect earth resistance in conformity with ≤ 10Ω。 Defend static earth resistance demand ≤ 100Ω the same.　Intelligent power supply earth system of building should adopt TNS system , should adopt according to norm one a total one mon to ground the device , namely unify the earth body. It is a earth electric potential datum point to unify the earth body , therefore draw various kinds of function earth lead wire separately, the way of the electric potential of utilize electric potential such as being total and auxiliarying etc. makes up an intact unified earth system. Generally, unify earth system usable pile reinforcing bar of building, and zincplated flatrolled steel link an organic whole it with 40* 4 (mm), as the natural earth body. According to norm, should systematic defending thunder earth share systematically , in conformity with ≤ 1Ωearth resistance its. If can not reach the requirement , must increase artificial earth body or adopt chemistry lower law of hindering , make ≤ 1Ω of earth resistance . In turn into distribution is it wait for electric potential copper arrange always to set up , copper this arrange one end through construct post or reinforcing bar of baseplate connect with unified earth body, another end join with exchanges neutral line , earth of system separately through different connection end son, with is it make safe protection earth every equipment join , with defend thunder39。關(guān)鍵詞:單點(diǎn)接地而且，隨著建筑物的要求不同，各類設(shè)備的功能不同，接地系統(tǒng)也相應(yīng)不同。　　TN－C系統(tǒng)被稱之為三相四線系統(tǒng)，該系統(tǒng)中性線N與保護(hù)接地PE合二為一，通稱PEN線。因此TN－C接地系統(tǒng)不能作為智能化建筑的接地系統(tǒng)。TN－S系統(tǒng)的特點(diǎn)是：中性線N與保護(hù)接地線PE在進(jìn)戶時(shí)共同接地后，不能再有任何電氣連接?！　N－S是一個(gè)三相四線加PE線的接地系統(tǒng)。該接地系統(tǒng)完全具備安全和可靠的基準(zhǔn)電位。　　通常稱TT系統(tǒng)為三相四線接地系統(tǒng)。只有單相接地故障時(shí)，由于保護(hù)接地靈敏度低，故障不能及時(shí)切斷，設(shè)備外殼才可能帶電。因此它是不適用于擁有大量單相設(shè)備的智能化大樓的。前面已經(jīng)分析過，在智能化大樓內(nèi)，單相用電設(shè)備較多，單相負(fù)荷比重較大，三相負(fù)荷通常是不平衡的，因此在中性線N中帶有隨機(jī)電流。：為把雷電流迅速導(dǎo)入大地，以防止雷害為目的的接地叫作防雷接地。不管是直擊，串擊，反擊都會(huì)使電子設(shè)備受到不同程度的損壞或嚴(yán)重干擾。這樣不僅可以有效防止雷擊損壞樓內(nèi)設(shè)備，而且還能防止外來(lái)的電磁干擾。工作接地主要指的是變壓器中性點(diǎn)或中性線（N線）接地。　　在高壓系統(tǒng)里，采用中性點(diǎn)接地方式可使接地繼電保護(hù)準(zhǔn)確動(dòng)作并消除單相電弧接地過電壓。在智能化樓宇內(nèi)，要求安全保護(hù)接地的設(shè)備非常多，有強(qiáng)電設(shè)備，弱電設(shè)備，以及一些非帶電導(dǎo)電設(shè)備與構(gòu)件，均必須采取安全保護(hù)接地措施。 　　如果裝有接地裝置的電氣設(shè)備的絕緣損壞使外殼帶電時(shí)，接地短路電流將同時(shí)沿著接地體和人體兩條通路流過，I=IL＋I(xiàn)P，我們知道：在一個(gè)并聯(lián)電路中，通過每條支路的電流值與電阻的大小成反比。即I≈IL。：在一幢智能化樓宇內(nèi)，包含有大量的計(jì)算機(jī)，通訊設(shè)備和帶有電腦的大樓自動(dòng)化設(shè)備。該引線不宜與PE線連接，嚴(yán)禁與N線連接。這些現(xiàn)象會(huì)對(duì)設(shè)計(jì)用來(lái)發(fā)送或接收很高傳輸頻率的設(shè)備產(chǎn)生很大的干擾。防靜電干擾也很重要。防靜電接地要求在潔靜干燥環(huán)境中，所有設(shè)備外殼及室內(nèi)（包括地坪）設(shè)施必須均與PE線多點(diǎn)可靠連接。通常情況下，統(tǒng)一接地系統(tǒng)可利用大樓的樁基鋼筋，并用404（mm）鍍鋅扁鋼將其連成一體，作為自然接地體。在智能大廈中，因?yàn)橄到y(tǒng)采用計(jì)算機(jī)參與管理或使用計(jì)算機(jī)作為工作工具，所以其接地系統(tǒng)宜采用單點(diǎn)接地并宜采取等電位措施。實(shí)際上這是混合接地，這種接法既不安全又會(huì)產(chǎn)生干擾，現(xiàn)在的規(guī)范是不允許的?？蓮臋C(jī)柜引出三個(gè)相互絕緣的接地端子，再由引線引到總等電位銅排上共同接地。若達(dá)不到要求，必須增加人工接地體或采用化學(xué)降阻法，使接地電阻≤1Ω。智能化樓宇的供電接地系統(tǒng)宜采用TN－S系統(tǒng)，按規(guī)范宜采用一個(gè)總的共同接地裝置，即統(tǒng)一接地體。例如在相對(duì)濕度10～20%、如果沒有良好的接地，不僅僅會(huì)產(chǎn)生對(duì)電子設(shè)備的干擾，甚至?xí)⒃O(shè)備芯片擊壞。屏蔽及其正確接地是防止電磁干擾的最佳保護(hù)方法。這些干擾的產(chǎn)生或者是因?yàn)閷?dǎo)線之間的耦合現(xiàn)象，或者是因?yàn)殡娙菪?yīng)或電感效應(yīng)。因此為了使其準(zhǔn)確性高，穩(wěn)定性好，除了需有一個(gè)穩(wěn)定的供電電源外，還必須具備一個(gè)穩(wěn)定的基準(zhǔn)電位。人站在大地上去碰觸設(shè)備的外殼時(shí)，人體所承受的電壓很低，不會(huì)有危險(xiǎn)。　IP—流經(jīng)人體的電流由上式可以看出，接地電阻越小，流經(jīng)人體的電流越小，通常人體電阻要比接地電阻大數(shù)百倍經(jīng)過人體的電流也比流過接地體的電流小數(shù)百倍。如果人體觸及此電氣設(shè)備的外殼就可能被電擊傷或造成生命危險(xiǎn)。：安全保護(hù)接地就是將電氣設(shè)備不帶電的金屬部分與接地體之間作良好的金屬連接。在配電中存在輔助等電位接線端子，等電位接線端子一般均在箱柜內(nèi)。防雷裝置如與電氣設(shè)備的工作接地合用一個(gè)總的接地網(wǎng)時(shí)，接地電阻應(yīng)符合其最小值要求。智能化樓宇的所有功能接地，必須以防雷接地系統(tǒng)為基礎(chǔ)，并建立嚴(yán)密，完整的防雷結(jié)構(gòu)。從已建成的大樓看，大樓的各層頂板，底板，側(cè)墻，吊頂內(nèi)幾乎被各種布線布滿。因此智能建筑應(yīng)設(shè)置電子設(shè)備的直流接地，交流工作接地，安全保護(hù)接地，及普通建筑也應(yīng)具備的防雷保護(hù)接地。如果采用TN－C系統(tǒng)，將TN－C系統(tǒng)中的N線同時(shí)用做接地線；或者在TN－S系統(tǒng)中將N線與PE線接在一起，再連接到底板上去；再或不設(shè)置電子設(shè)備的直流接地引線，而將直流接地直接接到PE線上；有的干脆把N線、PE線、直流接地線混接在一起。該系統(tǒng)的優(yōu)點(diǎn)是當(dāng)一相接地時(shí)，不會(huì)使外殼帶有較大的故障電流，系統(tǒng)可以照常運(yùn)行。隨著大容量的漏電保護(hù)器的出現(xiàn)，該系統(tǒng)也會(huì)越來(lái)越作為智能型建筑物的接地系統(tǒng)。TT系統(tǒng)的特點(diǎn)是中性線N與保護(hù)接地線PE無(wú)一點(diǎn)電氣連接，即中性點(diǎn)接地與PE線接地是分開的。如果計(jì)算機(jī)等電子設(shè)備沒有特殊的要求時(shí)，一般都采用這種接地系統(tǒng)。TN－S系統(tǒng)的特點(diǎn)是，中性線N與保護(hù)接地線PE除在變壓器中性點(diǎn)共同接地外，兩線不再有任何的電氣連接。PE線連接的設(shè)備外殼及金屬構(gòu)件在系統(tǒng)正常運(yùn)行時(shí),－,各自都從接地體一點(diǎn)引出,及選擇正確的接地電阻值使電子設(shè)備共同獲得一個(gè)等電位基準(zhǔn)點(diǎn)等